From patchwork Mon Jan 28 21:35:21 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Axboe X-Patchwork-Id: 10784855 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id D4811139A for ; Mon, 28 Jan 2019 21:35:50 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C29B52B363 for ; Mon, 28 Jan 2019 21:35:50 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id B67D42B52C; Mon, 28 Jan 2019 21:35:50 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 006B82B363 for ; Mon, 28 Jan 2019 21:35:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728026AbfA1Vft (ORCPT ); Mon, 28 Jan 2019 16:35:49 -0500 Received: from mail-it1-f193.google.com ([209.85.166.193]:38299 "EHLO mail-it1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726661AbfA1Vft (ORCPT ); Mon, 28 Jan 2019 16:35:49 -0500 Received: by mail-it1-f193.google.com with SMTP id z20so864146itc.3 for ; Mon, 28 Jan 2019 13:35:48 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=FY7i8A/t+ar+CVDsIpMVwrTPPHLhDb6dZzvnPNdG5Kc=; b=tD+izKTf/RvtHGxxpIPO06GijzUttam+cbly+QTFYVvyOYuUz+PE+B0TJlRrU4CUfb QBts6mHpfcCM0s6YQ1MaqQHg0eO+eki8OmoQLAaWMcPI8VG9YUKF4mt/t6stj4ceD+bz iS021fSmfx7jVYezMQQsUmj1lRWWhJNBorhLQ0sjKqVoshY5XpXIr4Wehfx6bi7xqrbn LBzuevZqSnyaEiWXyOXs6Rl9WRRg+beBWzJmBQ7MAyWWbJDdzy+ki1JGQyebk0sgDGZM Qlu9BCAH0QKR936oL22BjJL9vD4ydf8wm7p9ocjJSKs5hFtcifauRIaGuucLhLApN3oG i1tA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=FY7i8A/t+ar+CVDsIpMVwrTPPHLhDb6dZzvnPNdG5Kc=; b=AxsvGHla5qCjN6BN/jnDzvSlve0aMhIqoHHlUjSP8ss7zmNKyAd/Cpbtsi54IepPkJ oOv9ecn98gUgQi1lAF483yBzwrlPle2ffwkLhilAJ3r96p+F7SV2xSJ9RHO103f/0Lpp E/FTvIFueZWVm3XMko/fTWRhd4Mc/D5ytE21IVzm/29xHz3fo+ynYI3UsHmsafG+3dIN 7IWVKAhteX1VJIMfogbFFVi67re4WyGdw2ZwIG6cykbp4Qg9Uu0JRXozGOWOs5HFDZyC 8RU67zCPLOUboIz5PDzNx744yNFrmTwEmYRT5PvKoRvax5Z2C40ZobZj36hIaxEp4dRS 6KjQ== X-Gm-Message-State: AJcUukfewXncvnMN6fIm3pOLSdGalxhy0XA6LYoiBnbjBLkcyja0TogM h+iZequgWE9FsQkGVTN6cOvQQQ== X-Google-Smtp-Source: ALg8bN4R2/yKdZbaozBi6ZQUeEUR+1SeVmRFQZ9ErIHe0Bbfr6subtqEmVl5TlKf8TeetFUwS2Uqmw== X-Received: by 2002:a24:88:: with SMTP id 130mr4401012ita.92.1548711346749; Mon, 28 Jan 2019 13:35:46 -0800 (PST) Received: from localhost.localdomain ([216.160.245.98]) by smtp.gmail.com with ESMTPSA id u25sm13782077iob.23.2019.01.28.13.35.45 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 28 Jan 2019 13:35:45 -0800 (PST) From: Jens Axboe To: linux-aio@kvack.org, linux-block@vger.kernel.org, linux-man@vger.kernel.org, linux-api@vger.kernel.org Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, Jens Axboe Subject: [PATCH 01/18] fs: add an iopoll method to struct file_operations Date: Mon, 28 Jan 2019 14:35:21 -0700 Message-Id: <20190128213538.13486-2-axboe@kernel.dk> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190128213538.13486-1-axboe@kernel.dk> References: <20190128213538.13486-1-axboe@kernel.dk> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Christoph Hellwig This new methods is used to explicitly poll for I/O completion for an iocb. It must be called for any iocb submitted asynchronously (that is with a non-null ki_complete) which has the IOCB_HIPRI flag set. The method is assisted by a new ki_cookie field in struct iocb to store the polling cookie. Reviewed-by: Johannes Thumshirn Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe --- Documentation/filesystems/vfs.txt | 3 +++ include/linux/fs.h | 2 ++ 2 files changed, 5 insertions(+) diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt index 8dc8e9c2913f..761c6fd24a53 100644 --- a/Documentation/filesystems/vfs.txt +++ b/Documentation/filesystems/vfs.txt @@ -857,6 +857,7 @@ struct file_operations { ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *); ssize_t (*read_iter) (struct kiocb *, struct iov_iter *); ssize_t (*write_iter) (struct kiocb *, struct iov_iter *); + int (*iopoll)(struct kiocb *kiocb, bool spin); int (*iterate) (struct file *, struct dir_context *); int (*iterate_shared) (struct file *, struct dir_context *); __poll_t (*poll) (struct file *, struct poll_table_struct *); @@ -902,6 +903,8 @@ otherwise noted. write_iter: possibly asynchronous write with iov_iter as source + iopoll: called when aio wants to poll for completions on HIPRI iocbs + iterate: called when the VFS needs to read the directory contents iterate_shared: called when the VFS needs to read the directory contents diff --git a/include/linux/fs.h b/include/linux/fs.h index 811c77743dad..ccb0b7a63aa5 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -310,6 +310,7 @@ struct kiocb { int ki_flags; u16 ki_hint; u16 ki_ioprio; /* See linux/ioprio.h */ + unsigned int ki_cookie; /* for ->iopoll */ } __randomize_layout; static inline bool is_sync_kiocb(struct kiocb *kiocb) @@ -1786,6 +1787,7 @@ struct file_operations { ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *); ssize_t (*read_iter) (struct kiocb *, struct iov_iter *); ssize_t (*write_iter) (struct kiocb *, struct iov_iter *); + int (*iopoll)(struct kiocb *kiocb, bool spin); int (*iterate) (struct file *, struct dir_context *); int (*iterate_shared) (struct file *, struct dir_context *); __poll_t (*poll) (struct file *, struct poll_table_struct *); From patchwork Mon Jan 28 21:35:22 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Axboe X-Patchwork-Id: 10784857 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 609071390 for ; 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Mon, 28 Jan 2019 13:35:48 -0800 (PST) Received: from localhost.localdomain ([216.160.245.98]) by smtp.gmail.com with ESMTPSA id u25sm13782077iob.23.2019.01.28.13.35.46 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 28 Jan 2019 13:35:47 -0800 (PST) From: Jens Axboe To: linux-aio@kvack.org, linux-block@vger.kernel.org, linux-man@vger.kernel.org, linux-api@vger.kernel.org Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, Jens Axboe Subject: [PATCH 02/18] block: wire up block device iopoll method Date: Mon, 28 Jan 2019 14:35:22 -0700 Message-Id: <20190128213538.13486-3-axboe@kernel.dk> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190128213538.13486-1-axboe@kernel.dk> References: <20190128213538.13486-1-axboe@kernel.dk> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Christoph Hellwig Just call blk_poll on the iocb cookie, we can derive the block device from the inode trivially. Reviewed-by: Johannes Thumshirn Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe --- fs/block_dev.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/fs/block_dev.c b/fs/block_dev.c index 58a4c1217fa8..f18d076a2596 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -293,6 +293,14 @@ struct blkdev_dio { static struct bio_set blkdev_dio_pool; +static int blkdev_iopoll(struct kiocb *kiocb, bool wait) +{ + struct block_device *bdev = I_BDEV(kiocb->ki_filp->f_mapping->host); + struct request_queue *q = bdev_get_queue(bdev); + + return blk_poll(q, READ_ONCE(kiocb->ki_cookie), wait); +} + static void blkdev_bio_end_io(struct bio *bio) { struct blkdev_dio *dio = bio->bi_private; @@ -410,6 +418,7 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, int nr_pages) bio->bi_opf |= REQ_HIPRI; qc = submit_bio(bio); + WRITE_ONCE(iocb->ki_cookie, qc); break; } @@ -2076,6 +2085,7 @@ const struct file_operations def_blk_fops = { .llseek = block_llseek, .read_iter = blkdev_read_iter, .write_iter = blkdev_write_iter, + .iopoll = blkdev_iopoll, .mmap = generic_file_mmap, .fsync = blkdev_fsync, .unlocked_ioctl = block_ioctl, From patchwork Mon Jan 28 21:35:23 2019 Content-Type: text/plain; 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Mon, 28 Jan 2019 13:35:49 -0800 (PST) From: Jens Axboe To: linux-aio@kvack.org, linux-block@vger.kernel.org, linux-man@vger.kernel.org, linux-api@vger.kernel.org Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, Jens Axboe Subject: [PATCH 03/18] block: add bio_set_polled() helper Date: Mon, 28 Jan 2019 14:35:23 -0700 Message-Id: <20190128213538.13486-4-axboe@kernel.dk> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190128213538.13486-1-axboe@kernel.dk> References: <20190128213538.13486-1-axboe@kernel.dk> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP For the upcoming async polled IO, we can't sleep allocating requests. If we do, then we introduce a deadlock where the submitter already has async polled IO in-flight, but can't wait for them to complete since polled requests must be active found and reaped. Utilize the helper in the blockdev DIRECT_IO code. Reviewed-by: Christoph Hellwig Signed-off-by: Jens Axboe --- fs/block_dev.c | 4 ++-- include/linux/bio.h | 14 ++++++++++++++ 2 files changed, 16 insertions(+), 2 deletions(-) diff --git a/fs/block_dev.c b/fs/block_dev.c index f18d076a2596..392e2bfb636f 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -247,7 +247,7 @@ __blkdev_direct_IO_simple(struct kiocb *iocb, struct iov_iter *iter, task_io_account_write(ret); } if (iocb->ki_flags & IOCB_HIPRI) - bio.bi_opf |= REQ_HIPRI; + bio_set_polled(&bio, iocb); qc = submit_bio(&bio); for (;;) { @@ -415,7 +415,7 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, int nr_pages) nr_pages = iov_iter_npages(iter, BIO_MAX_PAGES); if (!nr_pages) { if (iocb->ki_flags & IOCB_HIPRI) - bio->bi_opf |= REQ_HIPRI; + bio_set_polled(bio, iocb); qc = submit_bio(bio); WRITE_ONCE(iocb->ki_cookie, qc); diff --git a/include/linux/bio.h b/include/linux/bio.h index 7380b094dcca..f6f0a2b3cbc8 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -823,5 +823,19 @@ static inline int bio_integrity_add_page(struct bio *bio, struct page *page, #endif /* CONFIG_BLK_DEV_INTEGRITY */ +/* + * Mark a bio as polled. Note that for async polled IO, the caller must + * expect -EWOULDBLOCK if we cannot allocate a request (or other resources). + * We cannot block waiting for requests on polled IO, as those completions + * must be found by the caller. This is different than IRQ driven IO, where + * it's safe to wait for IO to complete. + */ +static inline void bio_set_polled(struct bio *bio, struct kiocb *kiocb) +{ + bio->bi_opf |= REQ_HIPRI; + if (!is_sync_kiocb(kiocb)) + bio->bi_opf |= REQ_NOWAIT; +} + #endif /* CONFIG_BLOCK */ #endif /* __LINUX_BIO_H */ From patchwork Mon Jan 28 21:35:24 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Axboe X-Patchwork-Id: 10784861 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id D7F181390 for ; Mon, 28 Jan 2019 21:35:55 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C545B2B363 for ; Mon, 28 Jan 2019 21:35:55 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id B9D992B52C; Mon, 28 Jan 2019 21:35:55 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 9824D2B363 for ; Mon, 28 Jan 2019 21:35:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726774AbfA1Vfx (ORCPT ); Mon, 28 Jan 2019 16:35:53 -0500 Received: from mail-io1-f68.google.com ([209.85.166.68]:41509 "EHLO mail-io1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728035AbfA1Vfw (ORCPT ); Mon, 28 Jan 2019 16:35:52 -0500 Received: by mail-io1-f68.google.com with SMTP id s22so14829816ioc.8 for ; Mon, 28 Jan 2019 13:35:52 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=tkb1muQx9x9KnElGaaM03AUkKIKh+AW+Xsb0ZQn8sQk=; b=f1DV71bzsRWIM6U+an2ASgWTL9psTjokJLLCT/Ld/LTn9vYNa7r4r2LpH5W2lSa2Xu JDx1YvG4tmbJ+CAcvVQukpRRpJpjhAKzWXUu3VUB790zhW0D8NIAS5z38GTlLkxGjpxx 1qtbGQXvCAAJAbnffDEkvAM9lBzflPSyJ4pN+B/WxVFJcI/uOL5MVEZ3MCGtM8lqO02N IPq0+s6IrbH9jrNn423QvOv6/ZzL4Mr3Be/4qUboJXT01uQhXKu8Dp+ZIShO0pat4QSw e1++diGsUz+rbrPCQJCtOWA6uO8B6nyWN8l1Hzxpr6R28rV7rfqtfwDoMkCtp3TBzTwJ 6SDw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=tkb1muQx9x9KnElGaaM03AUkKIKh+AW+Xsb0ZQn8sQk=; b=XbMD7cJfykHsO3wLUNXpLKvQz1NC4UmU+yL89fRQEgqsYElSod5DMTh4L2Wt0KCZx8 cXA9EM27gNHTHkcjnzES+dN51RXoaZsiKoR1DfJ9bSegQp57Gk1MT68OZ1N89rg5kdhm 5u/PaqDTwB1veszEPoFpELEJSF4wbazo+hc+E1vm/vhee7tEGtJFvPwFJmjRtjO6r3EP X1DDO80Cm/Uh+mG4aLsfnrT2JPnGqSGLpk1UzYqKwN5ssXNmWwutb8i5OtUdfR2ujCz7 ud9UilhGXkKEIOBNGS0gBJ60E9P5UZqBLNV9SiXhiHxPvd/jOseq0rxHWT3VN5MgHKbh KMQg== X-Gm-Message-State: AHQUAuY008Deuff2PqcefTMldLfftUMv1FjzBAbBUDb/67iaovi7R9Zy xafUpmJXrixA5aHehp+fs39LIA== X-Google-Smtp-Source: AHgI3IYFG1ib5RZ07a0cL2Am0rkrrAb11onU0WFEEsmoyj2WhEGmQqznbOEW4fVXFgmdbufDiHIqMg== X-Received: by 2002:a5d:9812:: with SMTP id a18mr11383520iol.236.1548711351700; Mon, 28 Jan 2019 13:35:51 -0800 (PST) Received: from localhost.localdomain ([216.160.245.98]) by smtp.gmail.com with ESMTPSA id u25sm13782077iob.23.2019.01.28.13.35.50 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 28 Jan 2019 13:35:50 -0800 (PST) From: Jens Axboe To: linux-aio@kvack.org, linux-block@vger.kernel.org, linux-man@vger.kernel.org, linux-api@vger.kernel.org Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, Jens Axboe Subject: [PATCH 04/18] iomap: wire up the iopoll method Date: Mon, 28 Jan 2019 14:35:24 -0700 Message-Id: <20190128213538.13486-5-axboe@kernel.dk> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190128213538.13486-1-axboe@kernel.dk> References: <20190128213538.13486-1-axboe@kernel.dk> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Christoph Hellwig Store the request queue the last bio was submitted to in the iocb private data in addition to the cookie so that we find the right block device. Also refactor the common direct I/O bio submission code into a nice little helper. Signed-off-by: Christoph Hellwig Modified to use bio_set_polled(). Signed-off-by: Jens Axboe --- fs/gfs2/file.c | 2 ++ fs/iomap.c | 43 ++++++++++++++++++++++++++++--------------- fs/xfs/xfs_file.c | 1 + include/linux/iomap.h | 1 + 4 files changed, 32 insertions(+), 15 deletions(-) diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c index a2dea5bc0427..58a768e59712 100644 --- a/fs/gfs2/file.c +++ b/fs/gfs2/file.c @@ -1280,6 +1280,7 @@ const struct file_operations gfs2_file_fops = { .llseek = gfs2_llseek, .read_iter = gfs2_file_read_iter, .write_iter = gfs2_file_write_iter, + .iopoll = iomap_dio_iopoll, .unlocked_ioctl = gfs2_ioctl, .mmap = gfs2_mmap, .open = gfs2_open, @@ -1310,6 +1311,7 @@ const struct file_operations gfs2_file_fops_nolock = { .llseek = gfs2_llseek, .read_iter = gfs2_file_read_iter, .write_iter = gfs2_file_write_iter, + .iopoll = iomap_dio_iopoll, .unlocked_ioctl = gfs2_ioctl, .mmap = gfs2_mmap, .open = gfs2_open, diff --git a/fs/iomap.c b/fs/iomap.c index a3088fae567b..4ee50b76b4a1 100644 --- a/fs/iomap.c +++ b/fs/iomap.c @@ -1454,6 +1454,28 @@ struct iomap_dio { }; }; +int iomap_dio_iopoll(struct kiocb *kiocb, bool spin) +{ + struct request_queue *q = READ_ONCE(kiocb->private); + + if (!q) + return 0; + return blk_poll(q, READ_ONCE(kiocb->ki_cookie), spin); +} +EXPORT_SYMBOL_GPL(iomap_dio_iopoll); + +static void iomap_dio_submit_bio(struct iomap_dio *dio, struct iomap *iomap, + struct bio *bio) +{ + atomic_inc(&dio->ref); + + if (dio->iocb->ki_flags & IOCB_HIPRI) + bio_set_polled(bio, dio->iocb); + + dio->submit.last_queue = bdev_get_queue(iomap->bdev); + dio->submit.cookie = submit_bio(bio); +} + static ssize_t iomap_dio_complete(struct iomap_dio *dio) { struct kiocb *iocb = dio->iocb; @@ -1566,7 +1588,7 @@ static void iomap_dio_bio_end_io(struct bio *bio) } } -static blk_qc_t +static void iomap_dio_zero(struct iomap_dio *dio, struct iomap *iomap, loff_t pos, unsigned len) { @@ -1580,15 +1602,10 @@ iomap_dio_zero(struct iomap_dio *dio, struct iomap *iomap, loff_t pos, bio->bi_private = dio; bio->bi_end_io = iomap_dio_bio_end_io; - if (dio->iocb->ki_flags & IOCB_HIPRI) - flags |= REQ_HIPRI; - get_page(page); __bio_add_page(bio, page, len, 0); bio_set_op_attrs(bio, REQ_OP_WRITE, flags); - - atomic_inc(&dio->ref); - return submit_bio(bio); + iomap_dio_submit_bio(dio, iomap, bio); } static loff_t @@ -1691,9 +1708,6 @@ iomap_dio_bio_actor(struct inode *inode, loff_t pos, loff_t length, bio_set_pages_dirty(bio); } - if (dio->iocb->ki_flags & IOCB_HIPRI) - bio->bi_opf |= REQ_HIPRI; - iov_iter_advance(dio->submit.iter, n); dio->size += n; @@ -1701,11 +1715,7 @@ iomap_dio_bio_actor(struct inode *inode, loff_t pos, loff_t length, copied += n; nr_pages = iov_iter_npages(&iter, BIO_MAX_PAGES); - - atomic_inc(&dio->ref); - - dio->submit.last_queue = bdev_get_queue(iomap->bdev); - dio->submit.cookie = submit_bio(bio); + iomap_dio_submit_bio(dio, iomap, bio); } while (nr_pages); /* @@ -1916,6 +1926,9 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, if (dio->flags & IOMAP_DIO_WRITE_FUA) dio->flags &= ~IOMAP_DIO_NEED_SYNC; + WRITE_ONCE(iocb->ki_cookie, dio->submit.cookie); + WRITE_ONCE(iocb->private, dio->submit.last_queue); + if (!atomic_dec_and_test(&dio->ref)) { if (!dio->wait_for_completion) return -EIOCBQUEUED; diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index e47425071e65..60c2da41f0fc 100644 --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -1203,6 +1203,7 @@ const struct file_operations xfs_file_operations = { .write_iter = xfs_file_write_iter, .splice_read = generic_file_splice_read, .splice_write = iter_file_splice_write, + .iopoll = iomap_dio_iopoll, .unlocked_ioctl = xfs_file_ioctl, #ifdef CONFIG_COMPAT .compat_ioctl = xfs_file_compat_ioctl, diff --git a/include/linux/iomap.h b/include/linux/iomap.h index 9a4258154b25..0fefb5455bda 100644 --- a/include/linux/iomap.h +++ b/include/linux/iomap.h @@ -162,6 +162,7 @@ typedef int (iomap_dio_end_io_t)(struct kiocb *iocb, ssize_t ret, unsigned flags); ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, const struct iomap_ops *ops, iomap_dio_end_io_t end_io); +int iomap_dio_iopoll(struct kiocb *kiocb, bool spin); #ifdef CONFIG_SWAP struct file; 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Mon, 28 Jan 2019 13:35:52 -0800 (PST) From: Jens Axboe To: linux-aio@kvack.org, linux-block@vger.kernel.org, linux-man@vger.kernel.org, linux-api@vger.kernel.org Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, Jens Axboe Subject: [PATCH 05/18] Add io_uring IO interface Date: Mon, 28 Jan 2019 14:35:25 -0700 Message-Id: <20190128213538.13486-6-axboe@kernel.dk> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190128213538.13486-1-axboe@kernel.dk> References: <20190128213538.13486-1-axboe@kernel.dk> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The submission queue (SQ) and completion queue (CQ) rings are shared between the application and the kernel. This eliminates the need to copy data back and forth to submit and complete IO. IO submissions use the io_uring_sqe data structure, and completions are generated in the form of io_uring_sqe data structures. The SQ ring is an index into the io_uring_sqe array, which makes it possible to submit a batch of IOs without them being contiguous in the ring. The CQ ring is always contiguous, as completion events are inherently unordered, and hence any io_uring_cqe entry can point back to an arbitrary submission. Two new system calls are added for this: io_uring_setup(entries, params) Sets up a context for doing async IO. On success, returns a file descriptor that the application can mmap to gain access to the SQ ring, CQ ring, and io_uring_sqes. io_uring_enter(fd, to_submit, min_complete, flags, sigset, sigsetsize) Initiates IO against the rings mapped to this fd, or waits for them to complete, or both. The behavior is controlled by the parameters passed in. If 'to_submit' is non-zero, then we'll try and submit new IO. If IORING_ENTER_GETEVENTS is set, the kernel will wait for 'min_complete' events, if they aren't already available. It's valid to set IORING_ENTER_GETEVENTS and 'min_complete' == 0 at the same time, this allows the kernel to return already completed events without waiting for them. This is useful only for polling, as for IRQ driven IO, the application can just check the CQ ring without entering the kernel. With this setup, it's possible to do async IO with a single system call. Future developments will enable polled IO with this interface, and polled submission as well. The latter will enable an application to do IO without doing ANY system calls at all. For IRQ driven IO, an application only needs to enter the kernel for completions if it wants to wait for them to occur. Each io_uring is backed by a workqueue, to support buffered async IO as well. We will only punt to an async context if the command would need to wait for IO on the device side. Any data that can be accessed directly in the page cache is done inline. This avoids the slowness issue of usual threadpools, since cached data is accessed as quickly as a sync interface. Sample application: http://git.kernel.dk/cgit/fio/plain/t/io_uring.c Signed-off-by: Jens Axboe --- arch/x86/entry/syscalls/syscall_32.tbl | 2 + arch/x86/entry/syscalls/syscall_64.tbl | 2 + fs/Makefile | 1 + fs/io_uring.c | 1090 ++++++++++++++++++++++++ include/linux/syscalls.h | 6 + include/uapi/asm-generic/unistd.h | 6 +- include/uapi/linux/io_uring.h | 96 +++ init/Kconfig | 9 + kernel/sys_ni.c | 2 + 9 files changed, 1213 insertions(+), 1 deletion(-) create mode 100644 fs/io_uring.c create mode 100644 include/uapi/linux/io_uring.h diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl index 3cf7b533b3d1..481c126259e9 100644 --- a/arch/x86/entry/syscalls/syscall_32.tbl +++ b/arch/x86/entry/syscalls/syscall_32.tbl @@ -398,3 +398,5 @@ 384 i386 arch_prctl sys_arch_prctl __ia32_compat_sys_arch_prctl 385 i386 io_pgetevents sys_io_pgetevents __ia32_compat_sys_io_pgetevents 386 i386 rseq sys_rseq __ia32_sys_rseq +425 i386 io_uring_setup sys_io_uring_setup __ia32_sys_io_uring_setup +426 i386 io_uring_enter sys_io_uring_enter __ia32_sys_io_uring_enter diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl index f0b1709a5ffb..6a32a430c8e0 100644 --- a/arch/x86/entry/syscalls/syscall_64.tbl +++ b/arch/x86/entry/syscalls/syscall_64.tbl @@ -343,6 +343,8 @@ 332 common statx __x64_sys_statx 333 common io_pgetevents __x64_sys_io_pgetevents 334 common rseq __x64_sys_rseq +425 common io_uring_setup __x64_sys_io_uring_setup +426 common io_uring_enter __x64_sys_io_uring_enter # # x32-specific system call numbers start at 512 to avoid cache impact diff --git a/fs/Makefile b/fs/Makefile index 293733f61594..8e15d6fc4340 100644 --- a/fs/Makefile +++ b/fs/Makefile @@ -30,6 +30,7 @@ obj-$(CONFIG_TIMERFD) += timerfd.o obj-$(CONFIG_EVENTFD) += eventfd.o obj-$(CONFIG_USERFAULTFD) += userfaultfd.o obj-$(CONFIG_AIO) += aio.o +obj-$(CONFIG_IO_URING) += io_uring.o obj-$(CONFIG_FS_DAX) += dax.o obj-$(CONFIG_FS_ENCRYPTION) += crypto/ obj-$(CONFIG_FILE_LOCKING) += locks.o diff --git a/fs/io_uring.c b/fs/io_uring.c new file mode 100644 index 000000000000..309eed3629d2 --- /dev/null +++ b/fs/io_uring.c @@ -0,0 +1,1090 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Shared application/kernel submission and completion ring pairs, for + * supporting fast/efficient IO. + * + * Copyright (C) 2018-2019 Jens Axboe + */ +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include + +#include + +#include "internal.h" + +struct io_uring { + u32 head ____cacheline_aligned_in_smp; + u32 tail ____cacheline_aligned_in_smp; +}; + +struct io_sq_ring { + struct io_uring r; + u32 ring_mask; + u32 ring_entries; + u32 dropped; + u32 flags; + u32 array[]; +}; + +struct io_cq_ring { + struct io_uring r; + u32 ring_mask; + u32 ring_entries; + u32 overflow; + struct io_uring_cqe cqes[]; +}; + +struct io_ring_ctx { + struct { + struct percpu_ref refs; + } ____cacheline_aligned_in_smp; + + struct { + unsigned int flags; + + /* SQ ring */ + struct io_sq_ring *sq_ring; + unsigned cached_sq_head; + unsigned sq_entries; + unsigned sq_mask; + unsigned sq_thread_cpu; + struct io_uring_sqe *sq_sqes; + } ____cacheline_aligned_in_smp; + + /* IO offload */ + struct workqueue_struct *sqo_wq; + struct mm_struct *sqo_mm; + struct files_struct *sqo_files; + + struct { + /* CQ ring */ + struct io_cq_ring *cq_ring; + unsigned cached_cq_tail; + unsigned cq_entries; + unsigned cq_mask; + struct wait_queue_head cq_wait; + struct fasync_struct *cq_fasync; + } ____cacheline_aligned_in_smp; + + struct user_struct *user; + + struct completion ctx_done; + + struct { + struct mutex uring_lock; + wait_queue_head_t wait; + } ____cacheline_aligned_in_smp; + + struct { + spinlock_t completion_lock; + } ____cacheline_aligned_in_smp; +}; + +struct sqe_submit { + const struct io_uring_sqe *sqe; + unsigned index; +}; + +struct io_kiocb { + union { + struct kiocb rw; + struct sqe_submit submit; + }; + + struct io_ring_ctx *ctx; + struct list_head list; + unsigned int flags; +#define REQ_F_FORCE_NONBLOCK 1 /* inline submission attempt */ + u64 user_data; + + struct work_struct work; +}; + +#define IO_PLUG_THRESHOLD 2 + +static struct kmem_cache *req_cachep; + +static const struct file_operations io_uring_fops; + +static void io_ring_ctx_ref_free(struct percpu_ref *ref) +{ + struct io_ring_ctx *ctx = container_of(ref, struct io_ring_ctx, refs); + + complete(&ctx->ctx_done); +} + +static struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p) +{ + struct io_ring_ctx *ctx; + + ctx = kzalloc(sizeof(*ctx), GFP_KERNEL); + if (!ctx) + return NULL; + + if (percpu_ref_init(&ctx->refs, io_ring_ctx_ref_free, 0, GFP_KERNEL)) { + kfree(ctx); + return NULL; + } + + ctx->flags = p->flags; + init_waitqueue_head(&ctx->cq_wait); + init_completion(&ctx->ctx_done); + mutex_init(&ctx->uring_lock); + init_waitqueue_head(&ctx->wait); + spin_lock_init(&ctx->completion_lock); + return ctx; +} + +static void io_commit_cqring(struct io_ring_ctx *ctx) +{ + struct io_cq_ring *ring = ctx->cq_ring; + + if (ctx->cached_cq_tail != ring->r.tail) { + /* order cqe stores with ring update */ + smp_wmb(); + ring->r.tail = ctx->cached_cq_tail; + /* write side barrier of tail update, app has read side */ + smp_wmb(); + + if (wq_has_sleeper(&ctx->cq_wait)) { + wake_up_interruptible(&ctx->cq_wait); + kill_fasync(&ctx->cq_fasync, SIGIO, POLL_IN); + } + } +} + +static struct io_uring_cqe *io_get_cqring(struct io_ring_ctx *ctx) +{ + struct io_cq_ring *ring = ctx->cq_ring; + unsigned tail; + + tail = ctx->cached_cq_tail; + smp_rmb(); + if (tail + 1 == READ_ONCE(ring->r.head)) + return NULL; + + ctx->cached_cq_tail++; + return &ring->cqes[tail & ctx->cq_mask]; +} + +static void __io_cqring_add_event(struct io_ring_ctx *ctx, u64 ki_user_data, + long res, unsigned ev_flags) +{ + struct io_uring_cqe *cqe; + + /* + * If we can't get a cq entry, userspace overflowed the + * submission (by quite a lot). Increment the overflow count in + * the ring. + */ + cqe = io_get_cqring(ctx); + if (cqe) { + cqe->user_data = ki_user_data; + cqe->res = res; + cqe->flags = ev_flags; + io_commit_cqring(ctx); + } else + ctx->cq_ring->overflow++; + + if (waitqueue_active(&ctx->wait)) + wake_up(&ctx->wait); +} + +static void io_cqring_add_event(struct io_ring_ctx *ctx, u64 ki_user_data, + long res, unsigned ev_flags) +{ + unsigned long flags; + + spin_lock_irqsave(&ctx->completion_lock, flags); + __io_cqring_add_event(ctx, ki_user_data, res, ev_flags); + spin_unlock_irqrestore(&ctx->completion_lock, flags); +} + +static void io_ring_drop_ctx_refs(struct io_ring_ctx *ctx, unsigned refs) +{ + percpu_ref_put_many(&ctx->refs, refs); + + if (waitqueue_active(&ctx->wait)) + wake_up(&ctx->wait); +} + +static struct io_kiocb *io_get_req(struct io_ring_ctx *ctx) +{ + struct io_kiocb *req; + + /* safe to use the non tryget, as we're inside ring ref already */ + percpu_ref_get(&ctx->refs); + + req = kmem_cache_alloc(req_cachep, GFP_ATOMIC | __GFP_NOWARN); + if (req) { + req->ctx = ctx; + req->flags = 0; + return req; + } + + io_ring_drop_ctx_refs(ctx, 1); + return NULL; +} + +static void io_free_req(struct io_kiocb *req) +{ + io_ring_drop_ctx_refs(req->ctx, 1); + kmem_cache_free(req_cachep, req); +} + +static void kiocb_end_write(struct kiocb *kiocb) +{ + if (kiocb->ki_flags & IOCB_WRITE) { + struct inode *inode = file_inode(kiocb->ki_filp); + + /* + * Tell lockdep we inherited freeze protection from submission + * thread. + */ + if (S_ISREG(inode->i_mode)) + __sb_writers_acquired(inode->i_sb, SB_FREEZE_WRITE); + file_end_write(kiocb->ki_filp); + } +} + +static void io_complete_rw(struct kiocb *kiocb, long res, long res2) +{ + struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw); + + kiocb_end_write(kiocb); + + fput(kiocb->ki_filp); + io_cqring_add_event(req->ctx, req->user_data, res, 0); + io_free_req(req); +} + +static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe, + bool force_nonblock) +{ + struct kiocb *kiocb = &req->rw; + int ret; + + kiocb->ki_filp = fget(sqe->fd); + if (unlikely(!kiocb->ki_filp)) + return -EBADF; + kiocb->ki_pos = sqe->off; + kiocb->ki_flags = iocb_flags(kiocb->ki_filp); + kiocb->ki_hint = ki_hint_validate(file_write_hint(kiocb->ki_filp)); + if (sqe->ioprio) { + ret = ioprio_check_cap(sqe->ioprio); + if (ret) + goto out_fput; + + kiocb->ki_ioprio = sqe->ioprio; + } else + kiocb->ki_ioprio = get_current_ioprio(); + + ret = kiocb_set_rw_flags(kiocb, sqe->rw_flags); + if (unlikely(ret)) + goto out_fput; + if (force_nonblock) { + kiocb->ki_flags |= IOCB_NOWAIT; + req->flags |= REQ_F_FORCE_NONBLOCK; + } + if (kiocb->ki_flags & IOCB_HIPRI) { + ret = -EINVAL; + goto out_fput; + } + + kiocb->ki_complete = io_complete_rw; + return 0; +out_fput: + fput(kiocb->ki_filp); + return ret; +} + +static inline void io_rw_done(struct kiocb *kiocb, ssize_t ret) +{ + switch (ret) { + case -EIOCBQUEUED: + break; + case -ERESTARTSYS: + case -ERESTARTNOINTR: + case -ERESTARTNOHAND: + case -ERESTART_RESTARTBLOCK: + /* + * We can't just restart the syscall, since previously + * submitted sqes may already be in progress. Just fail this + * IO with EINTR. + */ + ret = -EINTR; + /* fall through */ + default: + kiocb->ki_complete(kiocb, ret, 0); + } +} + +static int io_import_iovec(struct io_ring_ctx *ctx, int rw, + const struct io_uring_sqe *sqe, + struct iovec **iovec, struct iov_iter *iter) +{ + void __user *buf = u64_to_user_ptr(sqe->addr); + +#ifdef CONFIG_COMPAT + if (in_compat_syscall()) + return compat_import_iovec(rw, buf, sqe->len, UIO_FASTIOV, + iovec, iter); +#endif + + return import_iovec(rw, buf, sqe->len, UIO_FASTIOV, iovec, iter); +} + +static ssize_t io_read(struct io_kiocb *req, const struct io_uring_sqe *sqe, + bool force_nonblock) +{ + struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs; + struct kiocb *kiocb = &req->rw; + struct iov_iter iter; + struct file *file; + ssize_t ret; + + ret = io_prep_rw(req, sqe, force_nonblock); + if (ret) + return ret; + file = kiocb->ki_filp; + + ret = -EBADF; + if (unlikely(!(file->f_mode & FMODE_READ))) + goto out_fput; + ret = -EINVAL; + if (unlikely(!file->f_op->read_iter)) + goto out_fput; + + ret = io_import_iovec(req->ctx, READ, sqe, &iovec, &iter); + if (ret) + goto out_fput; + + ret = rw_verify_area(READ, file, &kiocb->ki_pos, iov_iter_count(&iter)); + if (!ret) { + ssize_t ret2; + + /* Catch -EAGAIN return for forced non-blocking submission */ + ret2 = call_read_iter(file, kiocb, &iter); + if (!force_nonblock || ret2 != -EAGAIN) + io_rw_done(kiocb, ret2); + else + ret = -EAGAIN; + } + kfree(iovec); +out_fput: + if (unlikely(ret)) + fput(file); + return ret; +} + +static ssize_t io_write(struct io_kiocb *req, const struct io_uring_sqe *sqe, + bool force_nonblock) +{ + struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs; + struct kiocb *kiocb = &req->rw; + struct iov_iter iter; + struct file *file; + ssize_t ret; + + ret = io_prep_rw(req, sqe, force_nonblock); + if (ret) + return ret; + file = kiocb->ki_filp; + + ret = -EAGAIN; + if (force_nonblock && !(kiocb->ki_flags & IOCB_DIRECT)) + goto out_fput; + + ret = -EBADF; + if (unlikely(!(file->f_mode & FMODE_WRITE))) + goto out_fput; + ret = -EINVAL; + if (unlikely(!file->f_op->write_iter)) + goto out_fput; + + ret = io_import_iovec(req->ctx, WRITE, sqe, &iovec, &iter); + if (ret) + goto out_fput; + + ret = rw_verify_area(WRITE, file, &kiocb->ki_pos, + iov_iter_count(&iter)); + if (!ret) { + /* + * Open-code file_start_write here to grab freeze protection, + * which will be released by another thread in + * io_complete_rw(). Fool lockdep by telling it the lock got + * released so that it doesn't complain about the held lock when + * we return to userspace. + */ + if (S_ISREG(file_inode(file)->i_mode)) { + __sb_start_write(file_inode(file)->i_sb, + SB_FREEZE_WRITE, true); + __sb_writers_release(file_inode(file)->i_sb, + SB_FREEZE_WRITE); + } + kiocb->ki_flags |= IOCB_WRITE; + io_rw_done(kiocb, call_write_iter(file, kiocb, &iter)); + } + kfree(iovec); +out_fput: + if (unlikely(ret)) + fput(file); + return ret; +} + +/* + * IORING_OP_NOP just posts a completion event, nothing else. + */ +static int io_nop(struct io_kiocb *req, const struct io_uring_sqe *sqe) +{ + struct io_ring_ctx *ctx = req->ctx; + + io_cqring_add_event(ctx, sqe->user_data, 0, 0); + io_free_req(req); + return 0; +} + +static int __io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req, + struct sqe_submit *s, bool force_nonblock) +{ + const struct io_uring_sqe *sqe = s->sqe; + ssize_t ret; + + if (unlikely(s->index >= ctx->sq_entries)) + return -EINVAL; + req->user_data = sqe->user_data; + + ret = -EINVAL; + switch (sqe->opcode) { + case IORING_OP_NOP: + ret = io_nop(req, sqe); + break; + case IORING_OP_READV: + ret = io_read(req, sqe, force_nonblock); + break; + case IORING_OP_WRITEV: + ret = io_write(req, sqe, force_nonblock); + break; + default: + ret = -EINVAL; + break; + } + + return ret; +} + +static void io_sq_wq_submit_work(struct work_struct *work) +{ + struct io_kiocb *req = container_of(work, struct io_kiocb, work); + struct sqe_submit *s = &req->submit; + u64 user_data = s->sqe->user_data; + struct io_ring_ctx *ctx = req->ctx; + mm_segment_t old_fs = get_fs(); + struct files_struct *old_files; + int ret; + + /* Ensure we clear previously set forced non-block flag */ + req->flags &= ~REQ_F_FORCE_NONBLOCK; + + old_files = current->files; + current->files = ctx->sqo_files; + + if (!mmget_not_zero(ctx->sqo_mm)) { + ret = -EFAULT; + goto err; + } + + use_mm(ctx->sqo_mm); + set_fs(USER_DS); + + ret = __io_submit_sqe(ctx, req, s, false); + + set_fs(old_fs); + unuse_mm(ctx->sqo_mm); + mmput(ctx->sqo_mm); +err: + if (ret) { + io_cqring_add_event(ctx, user_data, ret, 0); + io_free_req(req); + } + current->files = old_files; +} + +static int io_submit_sqe(struct io_ring_ctx *ctx, struct sqe_submit *s) +{ + struct io_kiocb *req; + ssize_t ret; + + /* enforce forwards compatibility on users */ + if (unlikely(s->sqe->flags)) + return -EINVAL; + + req = io_get_req(ctx); + if (unlikely(!req)) + return -EAGAIN; + + ret = __io_submit_sqe(ctx, req, s, true); + if (ret == -EAGAIN) { + memcpy(&req->submit, s, sizeof(*s)); + INIT_WORK(&req->work, io_sq_wq_submit_work); + queue_work(ctx->sqo_wq, &req->work); + ret = 0; + } + if (ret) + io_free_req(req); + + return ret; +} + +static void io_commit_sqring(struct io_ring_ctx *ctx) +{ + struct io_sq_ring *ring = ctx->sq_ring; + + if (ctx->cached_sq_head != ring->r.head) { + ring->r.head = ctx->cached_sq_head; + /* write side barrier of head update, app has read side */ + smp_wmb(); + } +} + +/* + * Undo last io_get_sqring() + */ +static void io_drop_sqring(struct io_ring_ctx *ctx) +{ + ctx->cached_sq_head--; +} + +static bool io_get_sqring(struct io_ring_ctx *ctx, struct sqe_submit *s) +{ + struct io_sq_ring *ring = ctx->sq_ring; + unsigned head; + + /* + * The cached sq head (or cq tail) serves two purposes: + * + * 1) allows us to batch the cost of updating the user visible + * head updates. + * 2) allows the kernel side to track the head on its own, even + * though the application is the one updating it. + */ + head = ctx->cached_sq_head; + smp_rmb(); + if (head == READ_ONCE(ring->r.tail)) + return false; + + head = ring->array[head & ctx->sq_mask]; + if (head < ctx->sq_entries) { + s->index = head; + s->sqe = &ctx->sq_sqes[head]; + ctx->cached_sq_head++; + return true; + } + + /* drop invalid entries */ + ctx->cached_sq_head++; + ring->dropped++; + smp_wmb(); + return false; +} + +static int io_ring_submit(struct io_ring_ctx *ctx, unsigned int to_submit) +{ + int i, ret = 0, submit = 0; + struct blk_plug plug; + + if (to_submit > IO_PLUG_THRESHOLD) + blk_start_plug(&plug); + + for (i = 0; i < to_submit; i++) { + struct sqe_submit s; + + if (!io_get_sqring(ctx, &s)) + break; + + ret = io_submit_sqe(ctx, &s); + if (ret) { + io_drop_sqring(ctx); + break; + } + + submit++; + } + io_commit_sqring(ctx); + + if (to_submit > IO_PLUG_THRESHOLD) + blk_finish_plug(&plug); + + return submit ? submit : ret; +} + +/* + * Wait until events become available, if we don't already have some. The + * application must reap them itself, as they reside on the shared cq ring. + */ +static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events, + const sigset_t __user *sig, size_t sigsz) +{ + struct io_cq_ring *ring = ctx->cq_ring; + sigset_t ksigmask, sigsaved; + DEFINE_WAIT(wait); + int ret = 0; + + smp_rmb(); + if (ring->r.head != ring->r.tail) + return 0; + if (!min_events) + return 0; + + if (sig) { + ret = set_user_sigmask(sig, &ksigmask, &sigsaved, sigsz); + if (ret) + return ret; + } + + do { + prepare_to_wait(&ctx->wait, &wait, TASK_INTERRUPTIBLE); + + ret = 0; + smp_rmb(); + if (ring->r.head != ring->r.tail) + break; + + schedule(); + + ret = -EINTR; + if (signal_pending(current)) + break; + } while (1); + + finish_wait(&ctx->wait, &wait); + + if (sig) + restore_user_sigmask(sig, &sigsaved); + + return ring->r.head == ring->r.tail ? ret : 0; +} + +static int __io_uring_enter(struct io_ring_ctx *ctx, unsigned to_submit, + unsigned min_complete, unsigned flags, + const sigset_t __user *sig, size_t sigsz) +{ + int submitted, ret; + + submitted = ret = 0; + if (to_submit) { + submitted = io_ring_submit(ctx, to_submit); + if (submitted < 0) + return submitted; + } + if (flags & IORING_ENTER_GETEVENTS) { + /* + * The application could have included the 'to_submit' count + * in how many events it wanted to wait for. If we failed to + * submit the desired count, we may need to adjust the number + * of events to poll/wait for. + */ + if (submitted < to_submit) + min_complete = min_t(unsigned, submitted, min_complete); + + ret = io_cqring_wait(ctx, min_complete, sig, sigsz); + } + + return submitted ? submitted : ret; +} + +static int io_sq_offload_start(struct io_ring_ctx *ctx) +{ + int ret; + + ctx->sqo_mm = current->mm; + + /* + * This is safe since 'current' has the fd installed, and if that gets + * closed on exit, then fops->release() is invoked which waits for the + * async contexts to flush and exit before exiting. + */ + ret = -EBADF; + ctx->sqo_files = current->files; + if (!ctx->sqo_files) + goto err; + + /* Do QD, or 2 * CPUS, whatever is smallest */ + ctx->sqo_wq = alloc_workqueue("io_ring-wq", WQ_UNBOUND | WQ_FREEZABLE, + min(ctx->sq_entries - 1, 2 * num_online_cpus())); + if (!ctx->sqo_wq) { + ret = -ENOMEM; + goto err; + } + + return 0; +err: + if (ctx->sqo_files) + ctx->sqo_files = NULL; + ctx->sqo_mm = NULL; + return ret; +} + +static void __io_unaccount_mem(struct user_struct *user, unsigned long nr_pages) +{ + atomic_long_sub(nr_pages, &user->locked_vm); +} + +static void io_unaccount_mem(struct io_ring_ctx *ctx, unsigned long nr_pages) +{ + if (ctx->user) + __io_unaccount_mem(ctx->user, nr_pages); +} + +static int __io_account_mem(struct user_struct *user, unsigned long nr_pages) +{ + unsigned long page_limit, cur_pages, new_pages; + + /* Don't allow more pages than we can safely lock */ + page_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; + + do { + cur_pages = atomic_long_read(&user->locked_vm); + new_pages = cur_pages + nr_pages; + if (new_pages > page_limit) + return -ENOMEM; + } while (atomic_long_cmpxchg(&user->locked_vm, cur_pages, + new_pages) != cur_pages); + + return 0; +} + +static void io_mem_free(void *ptr) +{ + struct page *page = virt_to_head_page(ptr); + + if (put_page_testzero(page)) + free_compound_page(page); +} + +static void *io_mem_alloc(size_t size) +{ + gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN | __GFP_COMP | + __GFP_NORETRY; + + return (void *) __get_free_pages(gfp_flags, get_order(size)); +} + +static unsigned long ring_pages(unsigned sq_entries, unsigned cq_entries) +{ + struct io_sq_ring *sq_ring; + struct io_cq_ring *cq_ring; + size_t bytes; + + bytes = struct_size(sq_ring, array, sq_entries); + bytes += array_size(sizeof(struct io_uring_sqe), sq_entries); + bytes += struct_size(cq_ring, cqes, cq_entries); + + return (bytes + PAGE_SIZE - 1) / PAGE_SIZE; +} + +static void io_ring_ctx_free(struct io_ring_ctx *ctx) +{ + destroy_workqueue(ctx->sqo_wq); + + io_mem_free(ctx->sq_ring); + io_mem_free(ctx->sq_sqes); + io_mem_free(ctx->cq_ring); + + percpu_ref_exit(&ctx->refs); + io_unaccount_mem(ctx, ring_pages(ctx->sq_entries, ctx->cq_entries)); + kfree(ctx); +} + +static __poll_t io_uring_poll(struct file *file, poll_table *wait) +{ + struct io_ring_ctx *ctx = file->private_data; + __poll_t mask = 0; + + poll_wait(file, &ctx->cq_wait, wait); + smp_rmb(); + if (ctx->sq_ring->r.tail + 1 != ctx->cached_sq_head) + mask |= EPOLLOUT | EPOLLWRNORM; + if (ctx->cq_ring->r.head != ctx->cached_cq_tail) + mask |= EPOLLIN | EPOLLRDNORM; + + return mask; +} + +static int io_uring_fasync(int fd, struct file *file, int on) +{ + struct io_ring_ctx *ctx = file->private_data; + + return fasync_helper(fd, file, on, &ctx->cq_fasync); +} + +static void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx) +{ + mutex_lock(&ctx->uring_lock); + percpu_ref_kill(&ctx->refs); + mutex_unlock(&ctx->uring_lock); + + wait_for_completion(&ctx->ctx_done); + io_ring_ctx_free(ctx); +} + +static int io_uring_release(struct inode *inode, struct file *file) +{ + struct io_ring_ctx *ctx = file->private_data; + + file->private_data = NULL; + io_ring_ctx_wait_and_kill(ctx); + return 0; +} + +static int io_uring_mmap(struct file *file, struct vm_area_struct *vma) +{ + loff_t offset = (loff_t) vma->vm_pgoff << PAGE_SHIFT; + unsigned long sz = vma->vm_end - vma->vm_start; + struct io_ring_ctx *ctx = file->private_data; + unsigned long pfn; + struct page *page; + void *ptr; + + switch (offset) { + case IORING_OFF_SQ_RING: + ptr = ctx->sq_ring; + break; + case IORING_OFF_SQES: + ptr = ctx->sq_sqes; + break; + case IORING_OFF_CQ_RING: + ptr = ctx->cq_ring; + break; + default: + return -EINVAL; + } + + page = virt_to_head_page(ptr); + if (sz > (PAGE_SIZE << compound_order(page))) + return -EINVAL; + + pfn = virt_to_phys(ptr) >> PAGE_SHIFT; + return remap_pfn_range(vma, vma->vm_start, pfn, sz, vma->vm_page_prot); +} + +SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit, + u32, min_complete, u32, flags, const sigset_t __user *, sig, + size_t, sigsz) +{ + struct io_ring_ctx *ctx; + long ret = -EBADF; + struct fd f; + + f = fdget(fd); + if (!f.file) + return -EBADF; + + ret = -EOPNOTSUPP; + if (f.file->f_op != &io_uring_fops) + goto out_fput; + + ret = -ENXIO; + ctx = f.file->private_data; + if (!percpu_ref_tryget(&ctx->refs)) + goto out_fput; + + ret = -EBUSY; + if (!mutex_trylock(&ctx->uring_lock)) + goto out_ctx; + + ret = __io_uring_enter(ctx, to_submit, min_complete, flags, sig, sigsz); + mutex_unlock(&ctx->uring_lock); +out_ctx: + io_ring_drop_ctx_refs(ctx, 1); +out_fput: + fdput(f); + return ret; +} + +static const struct file_operations io_uring_fops = { + .release = io_uring_release, + .mmap = io_uring_mmap, + .poll = io_uring_poll, + .fasync = io_uring_fasync, +}; + +static int io_allocate_scq_urings(struct io_ring_ctx *ctx, + struct io_uring_params *p) +{ + struct io_sq_ring *sq_ring; + struct io_cq_ring *cq_ring; + size_t size; + + sq_ring = io_mem_alloc(struct_size(sq_ring, array, p->sq_entries)); + if (!sq_ring) + return -ENOMEM; + + ctx->sq_ring = sq_ring; + sq_ring->ring_mask = p->sq_entries - 1; + sq_ring->ring_entries = p->sq_entries; + ctx->sq_mask = sq_ring->ring_mask; + ctx->sq_entries = sq_ring->ring_entries; + + size = array_size(sizeof(struct io_uring_sqe), p->sq_entries); + if (size == SIZE_MAX) + return -EOVERFLOW; + + ctx->sq_sqes = io_mem_alloc(size); + if (!ctx->sq_sqes) { + io_mem_free(ctx->sq_ring); + return -ENOMEM; + } + + cq_ring = io_mem_alloc(struct_size(cq_ring, cqes, p->cq_entries)); + if (!cq_ring) { + io_mem_free(ctx->sq_ring); + io_mem_free(ctx->sq_sqes); + return -ENOMEM; + } + + ctx->cq_ring = cq_ring; + cq_ring->ring_mask = p->cq_entries - 1; + cq_ring->ring_entries = p->cq_entries; + ctx->cq_mask = cq_ring->ring_mask; + ctx->cq_entries = cq_ring->ring_entries; + return 0; +} + +static int io_uring_create(unsigned entries, struct io_uring_params *p) +{ + struct user_struct *user = NULL; + struct io_ring_ctx *ctx; + int ret; + + if (!entries || entries > IORING_MAX_ENTRIES) + return -EINVAL; + + /* + * Use twice as many entries for the CQ ring. It's possible for the + * application to drive a higher depth than the size of the SQ ring, + * since the sqes are only used at submission time. This allows for + * some flexibility in overcommitting a bit. + */ + p->sq_entries = roundup_pow_of_two(entries); + p->cq_entries = 2 * p->sq_entries; + + if (!capable(CAP_IPC_LOCK)) { + user = get_uid(current_user()); + ret = __io_account_mem(user, ring_pages(p->sq_entries, + p->cq_entries)); + if (ret) { + free_uid(user); + return ret; + } + } + + ctx = io_ring_ctx_alloc(p); + if (!ctx) { + __io_unaccount_mem(user, ring_pages(p->sq_entries, + p->cq_entries)); + free_uid(user); + return -ENOMEM; + } + ctx->user = user; + + ret = io_allocate_scq_urings(ctx, p); + if (ret) + goto err; + + ret = io_sq_offload_start(ctx); + if (ret) + goto err; + + ret = anon_inode_getfd("[io_uring]", &io_uring_fops, ctx, + O_RDWR | O_CLOEXEC); + if (ret < 0) + goto err; + + memset(&p->sq_off, 0, sizeof(p->sq_off)); + p->sq_off.head = offsetof(struct io_sq_ring, r.head); + p->sq_off.tail = offsetof(struct io_sq_ring, r.tail); + p->sq_off.ring_mask = offsetof(struct io_sq_ring, ring_mask); + p->sq_off.ring_entries = offsetof(struct io_sq_ring, ring_entries); + p->sq_off.flags = offsetof(struct io_sq_ring, flags); + p->sq_off.dropped = offsetof(struct io_sq_ring, dropped); + p->sq_off.array = offsetof(struct io_sq_ring, array); + + memset(&p->cq_off, 0, sizeof(p->cq_off)); + p->cq_off.head = offsetof(struct io_cq_ring, r.head); + p->cq_off.tail = offsetof(struct io_cq_ring, r.tail); + p->cq_off.ring_mask = offsetof(struct io_cq_ring, ring_mask); + p->cq_off.ring_entries = offsetof(struct io_cq_ring, ring_entries); + p->cq_off.overflow = offsetof(struct io_cq_ring, overflow); + p->cq_off.cqes = offsetof(struct io_cq_ring, cqes); + return ret; +err: + io_ring_ctx_wait_and_kill(ctx); + return ret; +} + +/* + * Sets up an aio uring context, and returns the fd. Applications asks for a + * ring size, we return the actual sq/cq ring sizes (among other things) in the + * params structure passed in. + */ +static long io_uring_setup(u32 entries, struct io_uring_params __user *params) +{ + struct io_uring_params p; + long ret; + int i; + + if (copy_from_user(&p, params, sizeof(p))) + return -EFAULT; + for (i = 0; i < ARRAY_SIZE(p.resv); i++) { + if (p.resv[i]) + return -EINVAL; + } + + if (p.flags) + return -EINVAL; + + ret = io_uring_create(entries, &p); + if (ret < 0) + return ret; + + if (copy_to_user(params, &p, sizeof(p))) + return -EFAULT; + + return ret; +} + +SYSCALL_DEFINE2(io_uring_setup, u32, entries, + struct io_uring_params __user *, params) +{ + return io_uring_setup(entries, params); +} + +static int __init io_uring_init(void) +{ + req_cachep = KMEM_CACHE(io_kiocb, SLAB_HWCACHE_ALIGN | SLAB_PANIC); + return 0; +}; +__initcall(io_uring_init); diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index 257cccba3062..3072dbaa7869 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -69,6 +69,7 @@ struct file_handle; struct sigaltstack; struct rseq; union bpf_attr; +struct io_uring_params; #include #include @@ -309,6 +310,11 @@ asmlinkage long sys_io_pgetevents_time32(aio_context_t ctx_id, struct io_event __user *events, struct old_timespec32 __user *timeout, const struct __aio_sigset *sig); +asmlinkage long sys_io_uring_setup(u32 entries, + struct io_uring_params __user *p); +asmlinkage long sys_io_uring_enter(unsigned int fd, u32 to_submit, + u32 min_complete, u32 flags, + const sigset_t __user *sig, size_t sigsz); /* fs/xattr.c */ asmlinkage long sys_setxattr(const char __user *path, const char __user *name, diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h index d90127298f12..87871e7b7ea7 100644 --- a/include/uapi/asm-generic/unistd.h +++ b/include/uapi/asm-generic/unistd.h @@ -740,9 +740,13 @@ __SC_COMP(__NR_io_pgetevents, sys_io_pgetevents, compat_sys_io_pgetevents) __SYSCALL(__NR_rseq, sys_rseq) #define __NR_kexec_file_load 294 __SYSCALL(__NR_kexec_file_load, sys_kexec_file_load) +#define __NR_io_uring_setup 425 +__SYSCALL(__NR_io_uring_setup, sys_io_uring_setup) +#define __NR_io_uring_enter 426 +__SYSCALL(__NR_io_uring_enter, sys_io_uring_enter) #undef __NR_syscalls -#define __NR_syscalls 295 +#define __NR_syscalls 427 /* * 32 bit systems traditionally used different diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h new file mode 100644 index 000000000000..ce65db9269a8 --- /dev/null +++ b/include/uapi/linux/io_uring.h @@ -0,0 +1,96 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +/* + * Header file for the io_uring interface. + * + * Copyright (C) 2019 Jens Axboe + * Copyright (C) 2019 Christoph Hellwig + */ +#ifndef LINUX_IO_URING_H +#define LINUX_IO_URING_H + +#include +#include + +#define IORING_MAX_ENTRIES 4096 + +/* + * IO submission data structure (Submission Queue Entry) + */ +struct io_uring_sqe { + __u8 opcode; /* type of operation for this sqe */ + __u8 flags; /* as of now unused */ + __u16 ioprio; /* ioprio for the request */ + __s32 fd; /* file descriptor to do IO on */ + __u64 off; /* offset into file */ + __u64 addr; /* pointer to buffer or iovecs */ + __u32 len; /* buffer size or number of iovecs */ + union { + __kernel_rwf_t rw_flags; + __u32 __resv; + }; + __u64 user_data; /* data to be passed back at completion time */ + __u64 __pad2[3]; +}; + +#define IORING_OP_NOP 0 +#define IORING_OP_READV 1 +#define IORING_OP_WRITEV 2 + +/* + * IO completion data structure (Completion Queue Entry) + */ +struct io_uring_cqe { + __u64 user_data; /* sqe->data submission passed back */ + __s32 res; /* result code for this event */ + __u32 flags; +}; + +/* + * Magic offsets for the application to mmap the data it needs + */ +#define IORING_OFF_SQ_RING 0ULL +#define IORING_OFF_CQ_RING 0x8000000ULL +#define IORING_OFF_SQES 0x10000000ULL + +/* + * Filled with the offset for mmap(2) + */ +struct io_sqring_offsets { + __u32 head; + __u32 tail; + __u32 ring_mask; + __u32 ring_entries; + __u32 flags; + __u32 dropped; + __u32 array; + __u32 resv[3]; +}; + +struct io_cqring_offsets { + __u32 head; + __u32 tail; + __u32 ring_mask; + __u32 ring_entries; + __u32 overflow; + __u32 cqes; + __u32 resv[4]; +}; + +/* + * io_uring_enter(2) flags + */ +#define IORING_ENTER_GETEVENTS (1 << 0) + +/* + * Passed in for io_uring_setup(2). Copied back with updated info on success + */ +struct io_uring_params { + __u32 sq_entries; + __u32 cq_entries; + __u32 flags; + __u16 resv[10]; + struct io_sqring_offsets sq_off; + struct io_cqring_offsets cq_off; +}; + +#endif diff --git a/init/Kconfig b/init/Kconfig index 513fa544a134..0cf723867e69 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1403,6 +1403,15 @@ config AIO by some high performance threaded applications. Disabling this option saves about 7k. +config IO_URING + bool "Enable IO uring support" if EXPERT + select ANON_INODES + default y + help + This option enables support for the io_uring interface, enabling + applications to submit and completion IO through submission and + completion rings that are shared between the kernel and application. + config ADVISE_SYSCALLS bool "Enable madvise/fadvise syscalls" if EXPERT default y diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c index ab9d0e3c6d50..ee5e523564bb 100644 --- a/kernel/sys_ni.c +++ b/kernel/sys_ni.c @@ -46,6 +46,8 @@ COND_SYSCALL(io_getevents); COND_SYSCALL(io_pgetevents); COND_SYSCALL_COMPAT(io_getevents); COND_SYSCALL_COMPAT(io_pgetevents); +COND_SYSCALL(io_uring_setup); +COND_SYSCALL(io_uring_enter); /* fs/xattr.c */ From patchwork Mon Jan 28 21:35:26 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Axboe X-Patchwork-Id: 10784863 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 1889E1390 for ; Mon, 28 Jan 2019 21:35:59 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0657D2B51A for ; Mon, 28 Jan 2019 21:35:59 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id EF04F2B552; Mon, 28 Jan 2019 21:35:58 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 8A6F92B51A for ; Mon, 28 Jan 2019 21:35:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728035AbfA1Vf5 (ORCPT ); Mon, 28 Jan 2019 16:35:57 -0500 Received: from mail-it1-f194.google.com ([209.85.166.194]:56300 "EHLO mail-it1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727156AbfA1Vf5 (ORCPT ); Mon, 28 Jan 2019 16:35:57 -0500 Received: by mail-it1-f194.google.com with SMTP id m62so906376ith.5 for ; Mon, 28 Jan 2019 13:35:56 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=8r3NrG14radg1cc9nOpeVXnMvLMDl7fB5/7Hgnpl5vg=; b=1mQE0ktQ3PbzQDOJ6YpvHF2lmmbnyRSK43TzAOCUafsWoXcv8ZmPd+/5twtXl2oVMf cvESjnUujE4I5A8PUNlVCN5KA0YHze3IpmlHe+dCnMt6yDytFpJJS6OA6RaU8RkYExPv NOq2HyAmXBdMEEGzRrsAuG+ivR+F5blILoioKPWHPDMF+rwO7wQaXOX9VZXLDOhZIQr8 B6S9D8r3tbNXhugx/wXHR/MnP0I9lMYs2vR4NF71m4D8hp0j/TDikXDlZc53W/0jazw9 Hf5lQ4XNqYSGhUk+JHUX0KOGVnJrF2cI3/335fe9N9+OfAiGO5OpD6nyZFU4AZ1aJmFk Rw4g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=8r3NrG14radg1cc9nOpeVXnMvLMDl7fB5/7Hgnpl5vg=; b=s1auZCawO6hqeqenAABZR/joI8l9UjJmUG1COJ7QJv7nDvrDAjl8fIa2Q5Q4S3hUgy 0qFdSc0jgmf3my+0kZqnNGc5Q1hCwbsiFcCHn+dJ4q3tK39iSCa+3Nqu9NYI+eoNiws/ UqKY1mWnZ2ciXFVlW+wQ8Oy68D/QBgKENfvAxX7k8TWYaer30y+pKArZwnl7UaGeQN1/ VEWqNNvKm+9C9Dsy11dso960Cgsto62nfFRqG0+Z5wkvpFtmQhpQUfJ0BWlwwUDTGQ2N 8PQ6kVALVZXfKcclWqM9M0HEZCpH/0KXhcyyAQ4ATLYtT7FiIPOU7HpuQlR6a/0bPX5w js5A== X-Gm-Message-State: AJcUukcG7W8T2AAleP1gNdp15sJ0XMJo23zT54IGNzo4PXNoFagcINLn PxxMDCLQ62MYtCSgWO+UZ/scAA== X-Google-Smtp-Source: ALg8bN4ZkBDQcCL1zWSQhZmMjVR3qc9S7EALWopNJCWcc7nPJEm/jHxSLWJFxx29QHcMtEDoE70/Hw== X-Received: by 2002:a02:1bc5:: with SMTP id 66mr15261028jas.105.1548711355930; Mon, 28 Jan 2019 13:35:55 -0800 (PST) Received: from localhost.localdomain ([216.160.245.98]) by smtp.gmail.com with ESMTPSA id u25sm13782077iob.23.2019.01.28.13.35.53 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 28 Jan 2019 13:35:54 -0800 (PST) From: Jens Axboe To: linux-aio@kvack.org, linux-block@vger.kernel.org, linux-man@vger.kernel.org, linux-api@vger.kernel.org Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, Jens Axboe Subject: [PATCH 06/18] io_uring: add fsync support Date: Mon, 28 Jan 2019 14:35:26 -0700 Message-Id: <20190128213538.13486-7-axboe@kernel.dk> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190128213538.13486-1-axboe@kernel.dk> References: <20190128213538.13486-1-axboe@kernel.dk> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Christoph Hellwig Add a new fsync opcode, which either syncs a range if one is passed, or the whole file if the offset and length fields are both cleared to zero. A flag is provided to use fdatasync semantics, that is only force out metadata which is required to retrieve the file data, but not others like metadata. Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe --- fs/io_uring.c | 34 ++++++++++++++++++++++++++++++++++ include/uapi/linux/io_uring.h | 8 +++++++- 2 files changed, 41 insertions(+), 1 deletion(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 309eed3629d2..7d2e6db08b05 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -4,6 +4,7 @@ * supporting fast/efficient IO. * * Copyright (C) 2018-2019 Jens Axboe + * Copyright (c) 2018-2019 Christoph Hellwig */ #include #include @@ -466,6 +467,36 @@ static int io_nop(struct io_kiocb *req, const struct io_uring_sqe *sqe) return 0; } +static int io_fsync(struct io_kiocb *req, const struct io_uring_sqe *sqe, + bool force_nonblock) +{ + struct io_ring_ctx *ctx = req->ctx; + loff_t end = sqe->off + sqe->len; + struct file *file; + int ret; + + /* fsync always requires a blocking context */ + if (force_nonblock) + return -EAGAIN; + + if (unlikely(sqe->addr || sqe->ioprio)) + return -EINVAL; + if (unlikely(sqe->fsync_flags & ~IORING_FSYNC_DATASYNC)) + return -EINVAL; + + file = fget(sqe->fd); + if (unlikely(!file)) + return -EBADF; + + ret = vfs_fsync_range(file, sqe->off, end > 0 ? end : LLONG_MAX, + sqe->fsync_flags & IORING_FSYNC_DATASYNC); + + fput(file); + io_cqring_add_event(ctx, sqe->user_data, ret, 0); + io_free_req(req); + return 0; +} + static int __io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req, struct sqe_submit *s, bool force_nonblock) { @@ -487,6 +518,9 @@ static int __io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req, case IORING_OP_WRITEV: ret = io_write(req, sqe, force_nonblock); break; + case IORING_OP_FSYNC: + ret = io_fsync(req, sqe, force_nonblock); + break; default: ret = -EINVAL; break; diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h index ce65db9269a8..ca503ded73e3 100644 --- a/include/uapi/linux/io_uring.h +++ b/include/uapi/linux/io_uring.h @@ -26,7 +26,7 @@ struct io_uring_sqe { __u32 len; /* buffer size or number of iovecs */ union { __kernel_rwf_t rw_flags; - __u32 __resv; + __u32 fsync_flags; }; __u64 user_data; /* data to be passed back at completion time */ __u64 __pad2[3]; @@ -35,6 +35,12 @@ struct io_uring_sqe { #define IORING_OP_NOP 0 #define IORING_OP_READV 1 #define IORING_OP_WRITEV 2 +#define IORING_OP_FSYNC 3 + +/* + * sqe->fsync_flags + */ +#define IORING_FSYNC_DATASYNC (1 << 0) /* * IO completion data structure (Completion Queue Entry) From patchwork Mon Jan 28 21:35:27 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Axboe X-Patchwork-Id: 10784867 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id DC6211390 for ; Mon, 28 Jan 2019 21:36:00 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C93312B363 for ; Mon, 28 Jan 2019 21:36:00 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id BD44D2B52C; 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Mon, 28 Jan 2019 13:35:57 -0800 (PST) Received: from localhost.localdomain ([216.160.245.98]) by smtp.gmail.com with ESMTPSA id u25sm13782077iob.23.2019.01.28.13.35.55 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 28 Jan 2019 13:35:56 -0800 (PST) From: Jens Axboe To: linux-aio@kvack.org, linux-block@vger.kernel.org, linux-man@vger.kernel.org, linux-api@vger.kernel.org Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, Jens Axboe Subject: [PATCH 07/18] io_uring: support for IO polling Date: Mon, 28 Jan 2019 14:35:27 -0700 Message-Id: <20190128213538.13486-8-axboe@kernel.dk> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190128213538.13486-1-axboe@kernel.dk> References: <20190128213538.13486-1-axboe@kernel.dk> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Add support for a polled io_uring context. When a read or write is submitted to a polled context, the application must poll for completions on the CQ ring through io_uring_enter(2). Polled IO may not generate IRQ completions, hence they need to be actively found by the application itself. To use polling, io_uring_setup() must be used with the IORING_SETUP_IOPOLL flag being set. It is illegal to mix and match polled and non-polled IO on an io_uring. Signed-off-by: Jens Axboe --- fs/io_uring.c | 262 ++++++++++++++++++++++++++++++++-- include/uapi/linux/io_uring.h | 5 + 2 files changed, 256 insertions(+), 11 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 7d2e6db08b05..ed5b605a1748 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -100,6 +100,8 @@ struct io_ring_ctx { struct { spinlock_t completion_lock; + bool poll_multi_file; + struct list_head poll_list; } ____cacheline_aligned_in_smp; }; @@ -118,12 +120,16 @@ struct io_kiocb { struct list_head list; unsigned int flags; #define REQ_F_FORCE_NONBLOCK 1 /* inline submission attempt */ +#define REQ_F_IOPOLL_COMPLETED 2 /* polled IO has completed */ +#define REQ_F_IOPOLL_EAGAIN 4 /* submission got EAGAIN */ u64 user_data; + u64 res; struct work_struct work; }; #define IO_PLUG_THRESHOLD 2 +#define IO_IOPOLL_BATCH 8 static struct kmem_cache *req_cachep; @@ -155,6 +161,7 @@ static struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p) mutex_init(&ctx->uring_lock); init_waitqueue_head(&ctx->wait); spin_lock_init(&ctx->completion_lock); + INIT_LIST_HEAD(&ctx->poll_list); return ctx; } @@ -190,8 +197,8 @@ static struct io_uring_cqe *io_get_cqring(struct io_ring_ctx *ctx) return &ring->cqes[tail & ctx->cq_mask]; } -static void __io_cqring_add_event(struct io_ring_ctx *ctx, u64 ki_user_data, - long res, unsigned ev_flags) +static void io_cqring_fill_event(struct io_ring_ctx *ctx, u64 ki_user_data, + long res, unsigned ev_flags) { struct io_uring_cqe *cqe; @@ -205,9 +212,15 @@ static void __io_cqring_add_event(struct io_ring_ctx *ctx, u64 ki_user_data, cqe->user_data = ki_user_data; cqe->res = res; cqe->flags = ev_flags; - io_commit_cqring(ctx); } else ctx->cq_ring->overflow++; +} + +static void __io_cqring_add_event(struct io_ring_ctx *ctx, u64 ki_user_data, + long res, unsigned ev_flags) +{ + io_cqring_fill_event(ctx, ki_user_data, res, ev_flags); + io_commit_cqring(ctx); if (waitqueue_active(&ctx->wait)) wake_up(&ctx->wait); @@ -249,12 +262,158 @@ static struct io_kiocb *io_get_req(struct io_ring_ctx *ctx) return NULL; } +static void io_free_req_many(struct io_ring_ctx *ctx, void **reqs, int *nr) +{ + if (*nr) { + kmem_cache_free_bulk(req_cachep, *nr, reqs); + io_ring_drop_ctx_refs(ctx, *nr); + *nr = 0; + } +} + static void io_free_req(struct io_kiocb *req) { io_ring_drop_ctx_refs(req->ctx, 1); kmem_cache_free(req_cachep, req); } +/* + * Find and free completed poll iocbs + */ +static void io_iopoll_complete(struct io_ring_ctx *ctx, unsigned int *nr_events, + struct list_head *done) +{ + void *reqs[IO_IOPOLL_BATCH]; + struct io_kiocb *req; + int to_free = 0; + + while (!list_empty(done)) { + req = list_first_entry(done, struct io_kiocb, list); + list_del(&req->list); + + io_cqring_fill_event(ctx, req->user_data, req->res, 0); + + reqs[to_free++] = req; + (*nr_events)++; + + fput(req->rw.ki_filp); + if (to_free == ARRAY_SIZE(reqs)) + io_free_req_many(ctx, reqs, &to_free); + } + io_commit_cqring(ctx); + + if (to_free) + io_free_req_many(ctx, reqs, &to_free); +} + +static int io_do_iopoll(struct io_ring_ctx *ctx, unsigned int *nr_events, + long min) +{ + struct io_kiocb *req, *tmp; + LIST_HEAD(done); + bool spin; + int ret; + + /* + * Only spin for completions if we don't have multiple devices hanging + * off our complete list, and we're under the requested amount. + */ + spin = !ctx->poll_multi_file && (*nr_events < min); + + ret = 0; + list_for_each_entry_safe(req, tmp, &ctx->poll_list, list) { + struct kiocb *kiocb = &req->rw; + + /* + * Move completed entries to our local list. If we find a + * request that requires polling, break out and complete + * the done list first, if we have entries there. + */ + if (req->flags & REQ_F_IOPOLL_COMPLETED) { + list_move_tail(&req->list, &done); + continue; + } + if (!list_empty(&done)) + break; + + ret = kiocb->ki_filp->f_op->iopoll(kiocb, spin); + if (ret < 0) + break; + + if (ret && spin) + spin = false; + ret = 0; + } + + if (!list_empty(&done)) + io_iopoll_complete(ctx, nr_events, &done); + + return ret; +} + +/* + * Poll for a mininum of 'min' events. Note that if min == 0 we consider that a + * non-spinning poll check - we'll still enter the driver poll loop, but only + * as a non-spinning completion check. + */ +static int io_iopoll_getevents(struct io_ring_ctx *ctx, unsigned int *nr_events, + long min) +{ + int ret; + + do { + if (list_empty(&ctx->poll_list)) + return 0; + + ret = io_do_iopoll(ctx, nr_events, min); + if (ret < 0) + break; + } while (min && *nr_events < min); + + if (ret < 0) + return ret; + + return *nr_events < min; +} + +/* + * We can't just wait for polled events to come to us, we have to actively + * find and complete them. + */ +static void io_iopoll_reap_events(struct io_ring_ctx *ctx) +{ + if (!(ctx->flags & IORING_SETUP_IOPOLL)) + return; + + mutex_lock(&ctx->uring_lock); + while (!list_empty(&ctx->poll_list)) { + unsigned int nr_events = 0; + + io_iopoll_getevents(ctx, &nr_events, 1); + } + mutex_unlock(&ctx->uring_lock); +} + +static int io_iopoll_check(struct io_ring_ctx *ctx, unsigned *nr_events, + long min) +{ + int ret = 0; + + do { + int tmin = 0; + + if (*nr_events < min) + tmin = min - *nr_events; + + ret = io_iopoll_getevents(ctx, nr_events, tmin); + if (ret <= 0) + break; + ret = 0; + } while (!*nr_events || !need_resched()); + + return ret; +} + static void kiocb_end_write(struct kiocb *kiocb) { if (kiocb->ki_flags & IOCB_WRITE) { @@ -281,9 +440,60 @@ static void io_complete_rw(struct kiocb *kiocb, long res, long res2) io_free_req(req); } +static void io_complete_rw_iopoll(struct kiocb *kiocb, long res, long res2) +{ + struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw); + + kiocb_end_write(kiocb); + + if (unlikely(res == -EAGAIN)) { + req->flags |= REQ_F_IOPOLL_EAGAIN; + } else { + req->flags |= REQ_F_IOPOLL_COMPLETED; + req->res = res; + } +} + +/* + * After the iocb has been issued, it's safe to be found on the poll list. + * Adding the kiocb to the list AFTER submission ensures that we don't + * find it from a io_iopoll_getevents() thread before the issuer is done + * accessing the kiocb cookie. + */ +static void io_iopoll_req_issued(struct io_kiocb *req) +{ + struct io_ring_ctx *ctx = req->ctx; + + /* + * Track whether we have multiple files in our lists. This will impact + * how we do polling eventually, not spinning if we're on potentially + * different devices. + */ + if (list_empty(&ctx->poll_list)) { + ctx->poll_multi_file = false; + } else if (!ctx->poll_multi_file) { + struct io_kiocb *list_req; + + list_req = list_first_entry(&ctx->poll_list, struct io_kiocb, + list); + if (list_req->rw.ki_filp != req->rw.ki_filp) + ctx->poll_multi_file = true; + } + + /* + * For fast devices, IO may have already completed. If it has, add + * it to the front so we find it first. + */ + if (req->flags & REQ_F_IOPOLL_COMPLETED) + list_add(&req->list, &ctx->poll_list); + else + list_add_tail(&req->list, &ctx->poll_list); +} + static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe, bool force_nonblock) { + struct io_ring_ctx *ctx = req->ctx; struct kiocb *kiocb = &req->rw; int ret; @@ -309,12 +519,21 @@ static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe, kiocb->ki_flags |= IOCB_NOWAIT; req->flags |= REQ_F_FORCE_NONBLOCK; } - if (kiocb->ki_flags & IOCB_HIPRI) { - ret = -EINVAL; - goto out_fput; - } + if (ctx->flags & IORING_SETUP_IOPOLL) { + ret = -EOPNOTSUPP; + if (!(kiocb->ki_flags & IOCB_DIRECT) || + !kiocb->ki_filp->f_op->iopoll) + goto out_fput; - kiocb->ki_complete = io_complete_rw; + kiocb->ki_flags |= IOCB_HIPRI; + kiocb->ki_complete = io_complete_rw_iopoll; + } else { + if (kiocb->ki_flags & IOCB_HIPRI) { + ret = -EINVAL; + goto out_fput; + } + kiocb->ki_complete = io_complete_rw; + } return 0; out_fput: fput(kiocb->ki_filp); @@ -462,6 +681,9 @@ static int io_nop(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_ring_ctx *ctx = req->ctx; + if (unlikely(ctx->flags & IORING_SETUP_IOPOLL)) + return -EINVAL; + io_cqring_add_event(ctx, sqe->user_data, 0, 0); io_free_req(req); return 0; @@ -479,6 +701,8 @@ static int io_fsync(struct io_kiocb *req, const struct io_uring_sqe *sqe, if (force_nonblock) return -EAGAIN; + if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) + return -EINVAL; if (unlikely(sqe->addr || sqe->ioprio)) return -EINVAL; if (unlikely(sqe->fsync_flags & ~IORING_FSYNC_DATASYNC)) @@ -526,7 +750,16 @@ static int __io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req, break; } - return ret; + if (ret) + return ret; + + if (ctx->flags & IORING_SETUP_IOPOLL) { + if (req->flags & REQ_F_IOPOLL_EAGAIN) + return -EAGAIN; + io_iopoll_req_issued(req); + } + + return 0; } static void io_sq_wq_submit_work(struct work_struct *work) @@ -734,6 +967,8 @@ static int __io_uring_enter(struct io_ring_ctx *ctx, unsigned to_submit, return submitted; } if (flags & IORING_ENTER_GETEVENTS) { + unsigned nr_events = 0; + /* * The application could have included the 'to_submit' count * in how many events it wanted to wait for. If we failed to @@ -743,7 +978,10 @@ static int __io_uring_enter(struct io_ring_ctx *ctx, unsigned to_submit, if (submitted < to_submit) min_complete = min_t(unsigned, submitted, min_complete); - ret = io_cqring_wait(ctx, min_complete, sig, sigsz); + if (ctx->flags & IORING_SETUP_IOPOLL) + ret = io_iopoll_check(ctx, &nr_events, min_complete); + else + ret = io_cqring_wait(ctx, min_complete, sig, sigsz); } return submitted ? submitted : ret; @@ -842,6 +1080,7 @@ static unsigned long ring_pages(unsigned sq_entries, unsigned cq_entries) static void io_ring_ctx_free(struct io_ring_ctx *ctx) { destroy_workqueue(ctx->sqo_wq); + io_iopoll_reap_events(ctx); io_mem_free(ctx->sq_ring); io_mem_free(ctx->sq_sqes); @@ -880,6 +1119,7 @@ static void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx) percpu_ref_kill(&ctx->refs); mutex_unlock(&ctx->uring_lock); + io_iopoll_reap_events(ctx); wait_for_completion(&ctx->ctx_done); io_ring_ctx_free(ctx); } @@ -1097,7 +1337,7 @@ static long io_uring_setup(u32 entries, struct io_uring_params __user *params) return -EINVAL; } - if (p.flags) + if (p.flags & ~IORING_SETUP_IOPOLL) return -EINVAL; ret = io_uring_create(entries, &p); diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h index ca503ded73e3..4fc5fbd07688 100644 --- a/include/uapi/linux/io_uring.h +++ b/include/uapi/linux/io_uring.h @@ -32,6 +32,11 @@ struct io_uring_sqe { __u64 __pad2[3]; }; +/* + * io_uring_setup() flags + */ +#define IORING_SETUP_IOPOLL (1 << 0) /* io_context is polled */ + #define IORING_OP_NOP 0 #define IORING_OP_READV 1 #define IORING_OP_WRITEV 2 From patchwork Mon Jan 28 21:35:28 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Axboe X-Patchwork-Id: 10784869 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 156EB1390 for ; Mon, 28 Jan 2019 21:36:02 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 032AF2B363 for ; 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Mon, 28 Jan 2019 13:35:59 -0800 (PST) Received: from localhost.localdomain ([216.160.245.98]) by smtp.gmail.com with ESMTPSA id u25sm13782077iob.23.2019.01.28.13.35.57 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 28 Jan 2019 13:35:58 -0800 (PST) From: Jens Axboe To: linux-aio@kvack.org, linux-block@vger.kernel.org, linux-man@vger.kernel.org, linux-api@vger.kernel.org Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, Jens Axboe Subject: [PATCH 08/18] fs: add fget_many() and fput_many() Date: Mon, 28 Jan 2019 14:35:28 -0700 Message-Id: <20190128213538.13486-9-axboe@kernel.dk> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190128213538.13486-1-axboe@kernel.dk> References: <20190128213538.13486-1-axboe@kernel.dk> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Some uses cases repeatedly get and put references to the same file, but the only exposed interface is doing these one at the time. As each of these entail an atomic inc or dec on a shared structure, that cost can add up. Add fget_many(), which works just like fget(), except it takes an argument for how many references to get on the file. Ditto fput_many(), which can drop an arbitrary number of references to a file. Reviewed-by: Christoph Hellwig Signed-off-by: Jens Axboe --- fs/file.c | 15 ++++++++++----- fs/file_table.c | 9 +++++++-- include/linux/file.h | 2 ++ include/linux/fs.h | 4 +++- 4 files changed, 22 insertions(+), 8 deletions(-) diff --git a/fs/file.c b/fs/file.c index 3209ee271c41..97df385d6ab0 100644 --- a/fs/file.c +++ b/fs/file.c @@ -705,7 +705,7 @@ void do_close_on_exec(struct files_struct *files) spin_unlock(&files->file_lock); } -static struct file *__fget(unsigned int fd, fmode_t mask) +static struct file *__fget(unsigned int fd, fmode_t mask, unsigned int refs) { struct files_struct *files = current->files; struct file *file; @@ -720,7 +720,7 @@ static struct file *__fget(unsigned int fd, fmode_t mask) */ if (file->f_mode & mask) file = NULL; - else if (!get_file_rcu(file)) + else if (!get_file_rcu_many(file, refs)) goto loop; } rcu_read_unlock(); @@ -728,15 +728,20 @@ static struct file *__fget(unsigned int fd, fmode_t mask) return file; } +struct file *fget_many(unsigned int fd, unsigned int refs) +{ + return __fget(fd, FMODE_PATH, refs); +} + struct file *fget(unsigned int fd) { - return __fget(fd, FMODE_PATH); + return __fget(fd, FMODE_PATH, 1); } EXPORT_SYMBOL(fget); struct file *fget_raw(unsigned int fd) { - return __fget(fd, 0); + return __fget(fd, 0, 1); } EXPORT_SYMBOL(fget_raw); @@ -767,7 +772,7 @@ static unsigned long __fget_light(unsigned int fd, fmode_t mask) return 0; return (unsigned long)file; } else { - file = __fget(fd, mask); + file = __fget(fd, mask, 1); if (!file) return 0; return FDPUT_FPUT | (unsigned long)file; diff --git a/fs/file_table.c b/fs/file_table.c index 5679e7fcb6b0..155d7514a094 100644 --- a/fs/file_table.c +++ b/fs/file_table.c @@ -326,9 +326,9 @@ void flush_delayed_fput(void) static DECLARE_DELAYED_WORK(delayed_fput_work, delayed_fput); -void fput(struct file *file) +void fput_many(struct file *file, unsigned int refs) { - if (atomic_long_dec_and_test(&file->f_count)) { + if (atomic_long_sub_and_test(refs, &file->f_count)) { struct task_struct *task = current; if (likely(!in_interrupt() && !(task->flags & PF_KTHREAD))) { @@ -347,6 +347,11 @@ void fput(struct file *file) } } +void fput(struct file *file) +{ + fput_many(file, 1); +} + /* * synchronous analog of fput(); for kernel threads that might be needed * in some umount() (and thus can't use flush_delayed_fput() without diff --git a/include/linux/file.h b/include/linux/file.h index 6b2fb032416c..3fcddff56bc4 100644 --- a/include/linux/file.h +++ b/include/linux/file.h @@ -13,6 +13,7 @@ struct file; extern void fput(struct file *); +extern void fput_many(struct file *, unsigned int); struct file_operations; struct vfsmount; @@ -44,6 +45,7 @@ static inline void fdput(struct fd fd) } extern struct file *fget(unsigned int fd); +extern struct file *fget_many(unsigned int fd, unsigned int refs); extern struct file *fget_raw(unsigned int fd); extern unsigned long __fdget(unsigned int fd); extern unsigned long __fdget_raw(unsigned int fd); diff --git a/include/linux/fs.h b/include/linux/fs.h index ccb0b7a63aa5..acaad78b6781 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -952,7 +952,9 @@ static inline struct file *get_file(struct file *f) atomic_long_inc(&f->f_count); return f; } -#define get_file_rcu(x) atomic_long_inc_not_zero(&(x)->f_count) +#define get_file_rcu_many(x, cnt) \ + atomic_long_add_unless(&(x)->f_count, (cnt), 0) +#define get_file_rcu(x) get_file_rcu_many((x), 1) #define fput_atomic(x) atomic_long_add_unless(&(x)->f_count, -1, 1) #define file_count(x) atomic_long_read(&(x)->f_count) From patchwork Mon Jan 28 21:35:29 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Axboe X-Patchwork-Id: 10784871 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id E97161390 for ; Mon, 28 Jan 2019 21:36:03 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D76A32B363 for ; Mon, 28 Jan 2019 21:36:03 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id CB88A2B52C; 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Mon, 28 Jan 2019 13:36:00 -0800 (PST) Received: from localhost.localdomain ([216.160.245.98]) by smtp.gmail.com with ESMTPSA id u25sm13782077iob.23.2019.01.28.13.35.59 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 28 Jan 2019 13:35:59 -0800 (PST) From: Jens Axboe To: linux-aio@kvack.org, linux-block@vger.kernel.org, linux-man@vger.kernel.org, linux-api@vger.kernel.org Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, Jens Axboe Subject: [PATCH 09/18] io_uring: use fget/fput_many() for file references Date: Mon, 28 Jan 2019 14:35:29 -0700 Message-Id: <20190128213538.13486-10-axboe@kernel.dk> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190128213538.13486-1-axboe@kernel.dk> References: <20190128213538.13486-1-axboe@kernel.dk> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Add a separate io_submit_state structure, to cache some of the things we need for IO submission. One such example is file reference batching. io_submit_state. We get as many references as the number of sqes we are submitting, and drop unused ones if we end up switching files. The assumption here is that we're usually only dealing with one fd, and if there are multiple, hopefuly they are at least somewhat ordered. Could trivially be extended to cover multiple fds, if needed. On the completion side we do the same thing, except this is trivially done just locally in io_iopoll_reap(). Signed-off-by: Jens Axboe --- fs/io_uring.c | 139 ++++++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 118 insertions(+), 21 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index ed5b605a1748..25bdd719690d 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -131,6 +131,19 @@ struct io_kiocb { #define IO_PLUG_THRESHOLD 2 #define IO_IOPOLL_BATCH 8 +struct io_submit_state { + struct blk_plug plug; + + /* + * File reference cache + */ + struct file *file; + unsigned int fd; + unsigned int has_refs; + unsigned int used_refs; + unsigned int ios_left; +}; + static struct kmem_cache *req_cachep; static const struct file_operations io_uring_fops; @@ -284,9 +297,11 @@ static void io_iopoll_complete(struct io_ring_ctx *ctx, unsigned int *nr_events, struct list_head *done) { void *reqs[IO_IOPOLL_BATCH]; + int file_count, to_free; + struct file *file = NULL; struct io_kiocb *req; - int to_free = 0; + file_count = to_free = 0; while (!list_empty(done)) { req = list_first_entry(done, struct io_kiocb, list); list_del(&req->list); @@ -296,12 +311,28 @@ static void io_iopoll_complete(struct io_ring_ctx *ctx, unsigned int *nr_events, reqs[to_free++] = req; (*nr_events)++; - fput(req->rw.ki_filp); + /* + * Batched puts of the same file, to avoid dirtying the + * file usage count multiple times, if avoidable. + */ + if (!file) { + file = req->rw.ki_filp; + file_count = 1; + } else if (file == req->rw.ki_filp) { + file_count++; + } else { + fput_many(file, file_count); + file = req->rw.ki_filp; + file_count = 1; + } + if (to_free == ARRAY_SIZE(reqs)) io_free_req_many(ctx, reqs, &to_free); } io_commit_cqring(ctx); + if (file) + fput_many(file, file_count); if (to_free) io_free_req_many(ctx, reqs, &to_free); } @@ -490,14 +521,56 @@ static void io_iopoll_req_issued(struct io_kiocb *req) list_add_tail(&req->list, &ctx->poll_list); } +static void io_file_put(struct io_submit_state *state, struct file *file) +{ + if (!state) { + fput(file); + } else if (state->file) { + int diff = state->has_refs - state->used_refs; + + if (diff) + fput_many(state->file, diff); + state->file = NULL; + } +} + +/* + * Get as many references to a file as we have IOs left in this submission, + * assuming most submissions are for one file, or at least that each file + * has more than one submission. + */ +static struct file *io_file_get(struct io_submit_state *state, int fd) +{ + if (!state) + return fget(fd); + + if (state->file) { + if (state->fd == fd) { + state->used_refs++; + state->ios_left--; + return state->file; + } + io_file_put(state, NULL); + } + state->file = fget_many(fd, state->ios_left); + if (!state->file) + return NULL; + + state->fd = fd; + state->has_refs = state->ios_left; + state->used_refs = 1; + state->ios_left--; + return state->file; +} + static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe, - bool force_nonblock) + bool force_nonblock, struct io_submit_state *state) { struct io_ring_ctx *ctx = req->ctx; struct kiocb *kiocb = &req->rw; int ret; - kiocb->ki_filp = fget(sqe->fd); + kiocb->ki_filp = io_file_get(state, sqe->fd); if (unlikely(!kiocb->ki_filp)) return -EBADF; kiocb->ki_pos = sqe->off; @@ -536,7 +609,7 @@ static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe, } return 0; out_fput: - fput(kiocb->ki_filp); + io_file_put(state, kiocb->ki_filp); return ret; } @@ -577,7 +650,7 @@ static int io_import_iovec(struct io_ring_ctx *ctx, int rw, } static ssize_t io_read(struct io_kiocb *req, const struct io_uring_sqe *sqe, - bool force_nonblock) + bool force_nonblock, struct io_submit_state *state) { struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs; struct kiocb *kiocb = &req->rw; @@ -585,7 +658,7 @@ static ssize_t io_read(struct io_kiocb *req, const struct io_uring_sqe *sqe, struct file *file; ssize_t ret; - ret = io_prep_rw(req, sqe, force_nonblock); + ret = io_prep_rw(req, sqe, force_nonblock, state); if (ret) return ret; file = kiocb->ki_filp; @@ -620,7 +693,7 @@ static ssize_t io_read(struct io_kiocb *req, const struct io_uring_sqe *sqe, } static ssize_t io_write(struct io_kiocb *req, const struct io_uring_sqe *sqe, - bool force_nonblock) + bool force_nonblock, struct io_submit_state *state) { struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs; struct kiocb *kiocb = &req->rw; @@ -628,7 +701,7 @@ static ssize_t io_write(struct io_kiocb *req, const struct io_uring_sqe *sqe, struct file *file; ssize_t ret; - ret = io_prep_rw(req, sqe, force_nonblock); + ret = io_prep_rw(req, sqe, force_nonblock, state); if (ret) return ret; file = kiocb->ki_filp; @@ -722,7 +795,8 @@ static int io_fsync(struct io_kiocb *req, const struct io_uring_sqe *sqe, } static int __io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req, - struct sqe_submit *s, bool force_nonblock) + struct sqe_submit *s, bool force_nonblock, + struct io_submit_state *state) { const struct io_uring_sqe *sqe = s->sqe; ssize_t ret; @@ -737,10 +811,10 @@ static int __io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req, ret = io_nop(req, sqe); break; case IORING_OP_READV: - ret = io_read(req, sqe, force_nonblock); + ret = io_read(req, sqe, force_nonblock, state); break; case IORING_OP_WRITEV: - ret = io_write(req, sqe, force_nonblock); + ret = io_write(req, sqe, force_nonblock, state); break; case IORING_OP_FSYNC: ret = io_fsync(req, sqe, force_nonblock); @@ -786,7 +860,7 @@ static void io_sq_wq_submit_work(struct work_struct *work) use_mm(ctx->sqo_mm); set_fs(USER_DS); - ret = __io_submit_sqe(ctx, req, s, false); + ret = __io_submit_sqe(ctx, req, s, false, NULL); set_fs(old_fs); unuse_mm(ctx->sqo_mm); @@ -799,7 +873,8 @@ static void io_sq_wq_submit_work(struct work_struct *work) current->files = old_files; } -static int io_submit_sqe(struct io_ring_ctx *ctx, struct sqe_submit *s) +static int io_submit_sqe(struct io_ring_ctx *ctx, struct sqe_submit *s, + struct io_submit_state *state) { struct io_kiocb *req; ssize_t ret; @@ -812,7 +887,7 @@ static int io_submit_sqe(struct io_ring_ctx *ctx, struct sqe_submit *s) if (unlikely(!req)) return -EAGAIN; - ret = __io_submit_sqe(ctx, req, s, true); + ret = __io_submit_sqe(ctx, req, s, true, state); if (ret == -EAGAIN) { memcpy(&req->submit, s, sizeof(*s)); INIT_WORK(&req->work, io_sq_wq_submit_work); @@ -825,6 +900,26 @@ static int io_submit_sqe(struct io_ring_ctx *ctx, struct sqe_submit *s) return ret; } +/* + * Batched submission is done, ensure local IO is flushed out. + */ +static void io_submit_state_end(struct io_submit_state *state) +{ + blk_finish_plug(&state->plug); + io_file_put(state, NULL); +} + +/* + * Start submission side cache. + */ +static void io_submit_state_start(struct io_submit_state *state, + struct io_ring_ctx *ctx, unsigned max_ios) +{ + blk_start_plug(&state->plug); + state->file = NULL; + state->ios_left = max_ios; +} + static void io_commit_sqring(struct io_ring_ctx *ctx) { struct io_sq_ring *ring = ctx->sq_ring; @@ -879,11 +974,13 @@ static bool io_get_sqring(struct io_ring_ctx *ctx, struct sqe_submit *s) static int io_ring_submit(struct io_ring_ctx *ctx, unsigned int to_submit) { + struct io_submit_state state, *statep = NULL; int i, ret = 0, submit = 0; - struct blk_plug plug; - if (to_submit > IO_PLUG_THRESHOLD) - blk_start_plug(&plug); + if (to_submit > IO_PLUG_THRESHOLD) { + io_submit_state_start(&state, ctx, to_submit); + statep = &state; + } for (i = 0; i < to_submit; i++) { struct sqe_submit s; @@ -891,7 +988,7 @@ static int io_ring_submit(struct io_ring_ctx *ctx, unsigned int to_submit) if (!io_get_sqring(ctx, &s)) break; - ret = io_submit_sqe(ctx, &s); + ret = io_submit_sqe(ctx, &s, statep); if (ret) { io_drop_sqring(ctx); break; @@ -901,8 +998,8 @@ static int io_ring_submit(struct io_ring_ctx *ctx, unsigned int to_submit) } io_commit_sqring(ctx); - if (to_submit > IO_PLUG_THRESHOLD) - blk_finish_plug(&plug); + if (statep) + io_submit_state_end(statep); return submit ? submit : ret; } From patchwork Mon Jan 28 21:35:30 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Axboe X-Patchwork-Id: 10784873 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 2E6D8139A for ; Mon, 28 Jan 2019 21:36:05 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 1BDCD2B363 for ; 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Mon, 28 Jan 2019 13:36:02 -0800 (PST) Received: from localhost.localdomain ([216.160.245.98]) by smtp.gmail.com with ESMTPSA id u25sm13782077iob.23.2019.01.28.13.36.00 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 28 Jan 2019 13:36:01 -0800 (PST) From: Jens Axboe To: linux-aio@kvack.org, linux-block@vger.kernel.org, linux-man@vger.kernel.org, linux-api@vger.kernel.org Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, Jens Axboe Subject: [PATCH 10/18] io_uring: batch io_kiocb allocation Date: Mon, 28 Jan 2019 14:35:30 -0700 Message-Id: <20190128213538.13486-11-axboe@kernel.dk> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190128213538.13486-1-axboe@kernel.dk> References: <20190128213538.13486-1-axboe@kernel.dk> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Similarly to how we use the state->ios_left to know how many references to get to a file, we can use it to allocate the io_kiocb's we need in bulk. Signed-off-by: Jens Axboe --- fs/io_uring.c | 39 ++++++++++++++++++++++++++++++++++++--- 1 file changed, 36 insertions(+), 3 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 25bdd719690d..a33f1b1709d0 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -134,6 +134,13 @@ struct io_kiocb { struct io_submit_state { struct blk_plug plug; + /* + * io_kiocb alloc cache + */ + void *reqs[IO_IOPOLL_BATCH]; + unsigned int free_reqs; + unsigned int cur_req; + /* * File reference cache */ @@ -257,20 +264,42 @@ static void io_ring_drop_ctx_refs(struct io_ring_ctx *ctx, unsigned refs) wake_up(&ctx->wait); } -static struct io_kiocb *io_get_req(struct io_ring_ctx *ctx) +static struct io_kiocb *io_get_req(struct io_ring_ctx *ctx, + struct io_submit_state *state) { + gfp_t gfp = GFP_ATOMIC | __GFP_NOWARN; struct io_kiocb *req; /* safe to use the non tryget, as we're inside ring ref already */ percpu_ref_get(&ctx->refs); - req = kmem_cache_alloc(req_cachep, GFP_ATOMIC | __GFP_NOWARN); + if (!state) + req = kmem_cache_alloc(req_cachep, gfp); + else if (!state->free_reqs) { + size_t sz; + int ret; + + sz = min_t(size_t, state->ios_left, ARRAY_SIZE(state->reqs)); + ret = kmem_cache_alloc_bulk(req_cachep, gfp, sz, + state->reqs); + if (ret <= 0) + goto out; + state->free_reqs = ret - 1; + state->cur_req = 1; + req = state->reqs[0]; + } else { + req = state->reqs[state->cur_req]; + state->free_reqs--; + state->cur_req++; + } + if (req) { req->ctx = ctx; req->flags = 0; return req; } +out: io_ring_drop_ctx_refs(ctx, 1); return NULL; } @@ -883,7 +912,7 @@ static int io_submit_sqe(struct io_ring_ctx *ctx, struct sqe_submit *s, if (unlikely(s->sqe->flags)) return -EINVAL; - req = io_get_req(ctx); + req = io_get_req(ctx, state); if (unlikely(!req)) return -EAGAIN; @@ -907,6 +936,9 @@ static void io_submit_state_end(struct io_submit_state *state) { blk_finish_plug(&state->plug); io_file_put(state, NULL); + if (state->free_reqs) + kmem_cache_free_bulk(req_cachep, state->free_reqs, + &state->reqs[state->cur_req]); } /* @@ -916,6 +948,7 @@ static void io_submit_state_start(struct io_submit_state *state, struct io_ring_ctx *ctx, unsigned max_ios) { blk_start_plug(&state->plug); + state->free_reqs = 0; state->file = NULL; state->ios_left = max_ios; } From patchwork Mon Jan 28 21:35:31 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Axboe X-Patchwork-Id: 10784875 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 21352139A for ; Mon, 28 Jan 2019 21:36:07 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0FA132B363 for ; Mon, 28 Jan 2019 21:36:07 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 03BB12B52C; Mon, 28 Jan 2019 21:36:07 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 71EDF2B363 for ; 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Mon, 28 Jan 2019 13:36:03 -0800 (PST) From: Jens Axboe To: linux-aio@kvack.org, linux-block@vger.kernel.org, linux-man@vger.kernel.org, linux-api@vger.kernel.org Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, Jens Axboe Subject: [PATCH 11/18] block: implement bio helper to add iter bvec pages to bio Date: Mon, 28 Jan 2019 14:35:31 -0700 Message-Id: <20190128213538.13486-12-axboe@kernel.dk> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190128213538.13486-1-axboe@kernel.dk> References: <20190128213538.13486-1-axboe@kernel.dk> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP For an ITER_BVEC, we can just iterate the iov and add the pages to the bio directly. This requires that the caller doesn't releases the pages on IO completion, we add a BIO_NO_PAGE_REF flag for that. The current two callers of bio_iov_iter_get_pages() are updated to check if they need to release pages on completion. This makes them work with bvecs that contain kernel mapped pages already. Reviewed-by: Christoph Hellwig Signed-off-by: Jens Axboe --- block/bio.c | 59 ++++++++++++++++++++++++++++++++------- fs/block_dev.c | 5 ++-- fs/iomap.c | 5 ++-- include/linux/blk_types.h | 1 + 4 files changed, 56 insertions(+), 14 deletions(-) diff --git a/block/bio.c b/block/bio.c index 4db1008309ed..330df572cfb8 100644 --- a/block/bio.c +++ b/block/bio.c @@ -828,6 +828,23 @@ int bio_add_page(struct bio *bio, struct page *page, } EXPORT_SYMBOL(bio_add_page); +static int __bio_iov_bvec_add_pages(struct bio *bio, struct iov_iter *iter) +{ + const struct bio_vec *bv = iter->bvec; + unsigned int len; + size_t size; + + len = min_t(size_t, bv->bv_len, iter->count); + size = bio_add_page(bio, bv->bv_page, len, + bv->bv_offset + iter->iov_offset); + if (size == len) { + iov_iter_advance(iter, size); + return 0; + } + + return -EINVAL; +} + #define PAGE_PTRS_PER_BVEC (sizeof(struct bio_vec) / sizeof(struct page *)) /** @@ -876,23 +893,43 @@ static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) } /** - * bio_iov_iter_get_pages - pin user or kernel pages and add them to a bio + * bio_iov_iter_get_pages - add user or kernel pages to a bio * @bio: bio to add pages to - * @iter: iov iterator describing the region to be mapped + * @iter: iov iterator describing the region to be added + * + * This takes either an iterator pointing to user memory, or one pointing to + * kernel pages (BVEC iterator). If we're adding user pages, we pin them and + * map them into the kernel. On IO completion, the caller should put those + * pages. If we're adding kernel pages, we just have to add the pages to the + * bio directly. We don't grab an extra reference to those pages (the user + * should already have that), and we don't put the page on IO completion. + * The caller needs to check if the bio is flagged BIO_NO_PAGE_REF on IO + * completion. If it isn't, then pages should be released. * - * Pins pages from *iter and appends them to @bio's bvec array. The - * pages will have to be released using put_page() when done. * The function tries, but does not guarantee, to pin as many pages as - * fit into the bio, or are requested in *iter, whatever is smaller. - * If MM encounters an error pinning the requested pages, it stops. - * Error is returned only if 0 pages could be pinned. + * fit into the bio, or are requested in *iter, whatever is smaller. If + * MM encounters an error pinning the requested pages, it stops. Error + * is returned only if 0 pages could be pinned. */ int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) { + const bool is_bvec = iov_iter_is_bvec(iter); unsigned short orig_vcnt = bio->bi_vcnt; + /* + * If this is a BVEC iter, then the pages are kernel pages. Don't + * release them on IO completion. + */ + if (is_bvec) + bio_set_flag(bio, BIO_NO_PAGE_REF); + do { - int ret = __bio_iov_iter_get_pages(bio, iter); + int ret; + + if (is_bvec) + ret = __bio_iov_bvec_add_pages(bio, iter); + else + ret = __bio_iov_iter_get_pages(bio, iter); if (unlikely(ret)) return bio->bi_vcnt > orig_vcnt ? 0 : ret; @@ -1634,7 +1671,8 @@ static void bio_dirty_fn(struct work_struct *work) next = bio->bi_private; bio_set_pages_dirty(bio); - bio_release_pages(bio); + if (!bio_flagged(bio, BIO_NO_PAGE_REF)) + bio_release_pages(bio); bio_put(bio); } } @@ -1650,7 +1688,8 @@ void bio_check_pages_dirty(struct bio *bio) goto defer; } - bio_release_pages(bio); + if (!bio_flagged(bio, BIO_NO_PAGE_REF)) + bio_release_pages(bio); bio_put(bio); return; defer: diff --git a/fs/block_dev.c b/fs/block_dev.c index 392e2bfb636f..051ab41d1c61 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -338,8 +338,9 @@ static void blkdev_bio_end_io(struct bio *bio) struct bio_vec *bvec; int i; - bio_for_each_segment_all(bvec, bio, i) - put_page(bvec->bv_page); + if (!bio_flagged(bio, BIO_NO_PAGE_REF)) + bio_for_each_segment_all(bvec, bio, i) + put_page(bvec->bv_page); bio_put(bio); } } diff --git a/fs/iomap.c b/fs/iomap.c index 4ee50b76b4a1..e5c48a0b20e0 100644 --- a/fs/iomap.c +++ b/fs/iomap.c @@ -1582,8 +1582,9 @@ static void iomap_dio_bio_end_io(struct bio *bio) struct bio_vec *bvec; int i; - bio_for_each_segment_all(bvec, bio, i) - put_page(bvec->bv_page); + if (!bio_flagged(bio, BIO_NO_PAGE_REF)) + bio_for_each_segment_all(bvec, bio, i) + put_page(bvec->bv_page); bio_put(bio); } } diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h index d66bf5f32610..791fee35df88 100644 --- a/include/linux/blk_types.h +++ b/include/linux/blk_types.h @@ -215,6 +215,7 @@ struct bio { /* * bio flags */ +#define BIO_NO_PAGE_REF 0 /* don't put release vec pages */ #define BIO_SEG_VALID 1 /* bi_phys_segments valid */ #define BIO_CLONED 2 /* doesn't own data */ #define BIO_BOUNCED 3 /* bio is a bounce bio */ From patchwork Mon Jan 28 21:35:32 2019 Content-Type: text/plain; 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Mon, 28 Jan 2019 13:36:04 -0800 (PST) From: Jens Axboe To: linux-aio@kvack.org, linux-block@vger.kernel.org, linux-man@vger.kernel.org, linux-api@vger.kernel.org Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, Jens Axboe Subject: [PATCH 12/18] io_uring: add support for pre-mapped user IO buffers Date: Mon, 28 Jan 2019 14:35:32 -0700 Message-Id: <20190128213538.13486-13-axboe@kernel.dk> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190128213538.13486-1-axboe@kernel.dk> References: <20190128213538.13486-1-axboe@kernel.dk> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP If we have fixed user buffers, we can map them into the kernel when we setup the io_context. That avoids the need to do get_user_pages() for each and every IO. To utilize this feature, the application must call io_uring_register() after having setup an io_uring context, passing in IORING_REGISTER_BUFFERS as the opcode. The argument must be a pointer to an iovec array, and the nr_args should contain how many iovecs the application wishes to map. If successful, these buffers are now mapped into the kernel, eligible for IO. To use these fixed buffers, the application must use the IORING_OP_READ_FIXED and IORING_OP_WRITE_FIXED opcodes, and then set sqe->index to the desired buffer index. sqe->addr..sqe->addr+seq->len must point to somewhere inside the indexed buffer. The application may register buffers throughout the lifetime of the io_uring context. It can call io_uring_register() with IORING_UNREGISTER_BUFFERS as the opcode to unregister the current set of buffers, and then register a new set. The application need not unregister buffers explicitly before shutting down the io_uring context. It's perfectly valid to setup a larger buffer, and then sometimes only use parts of it for an IO. As long as the range is within the originally mapped region, it will work just fine. For now, buffers must not be file backed. If file backed buffers are passed in, the registration will fail with -1/EOPNOTSUPP. This restriction may be relaxed in the future. RLIMIT_MEMLOCK is used to check how much memory we can pin. A somewhat arbitrary 1G per buffer size is also imposed. Signed-off-by: Jens Axboe --- arch/x86/entry/syscalls/syscall_32.tbl | 1 + arch/x86/entry/syscalls/syscall_64.tbl | 1 + fs/io_uring.c | 356 ++++++++++++++++++++++++- include/linux/sched/user.h | 2 +- include/linux/syscalls.h | 2 + include/uapi/asm-generic/unistd.h | 4 +- include/uapi/linux/io_uring.h | 13 +- kernel/sys_ni.c | 1 + 8 files changed, 366 insertions(+), 14 deletions(-) diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl index 481c126259e9..2eefd2a7c1ce 100644 --- a/arch/x86/entry/syscalls/syscall_32.tbl +++ b/arch/x86/entry/syscalls/syscall_32.tbl @@ -400,3 +400,4 @@ 386 i386 rseq sys_rseq __ia32_sys_rseq 425 i386 io_uring_setup sys_io_uring_setup __ia32_sys_io_uring_setup 426 i386 io_uring_enter sys_io_uring_enter __ia32_sys_io_uring_enter +427 i386 io_uring_register sys_io_uring_register __ia32_sys_io_uring_register diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl index 6a32a430c8e0..65c026185e61 100644 --- a/arch/x86/entry/syscalls/syscall_64.tbl +++ b/arch/x86/entry/syscalls/syscall_64.tbl @@ -345,6 +345,7 @@ 334 common rseq __x64_sys_rseq 425 common io_uring_setup __x64_sys_io_uring_setup 426 common io_uring_enter __x64_sys_io_uring_enter +427 common io_uring_register __x64_sys_io_uring_register # # x32-specific system call numbers start at 512 to avoid cache impact diff --git a/fs/io_uring.c b/fs/io_uring.c index a33f1b1709d0..682714d6f217 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -25,8 +25,10 @@ #include #include #include +#include #include #include +#include #include #include @@ -57,6 +59,13 @@ struct io_cq_ring { struct io_uring_cqe cqes[]; }; +struct io_mapped_ubuf { + u64 ubuf; + size_t len; + struct bio_vec *bvec; + unsigned int nr_bvecs; +}; + struct io_ring_ctx { struct { struct percpu_ref refs; @@ -89,6 +98,10 @@ struct io_ring_ctx { struct fasync_struct *cq_fasync; } ____cacheline_aligned_in_smp; + /* if used, fixed mapped user buffers */ + unsigned nr_user_bufs; + struct io_mapped_ubuf *user_bufs; + struct user_struct *user; struct completion ctx_done; @@ -663,12 +676,51 @@ static inline void io_rw_done(struct kiocb *kiocb, ssize_t ret) } } +static int io_import_fixed(struct io_ring_ctx *ctx, int rw, + const struct io_uring_sqe *sqe, + struct iov_iter *iter) +{ + struct io_mapped_ubuf *imu; + size_t len = sqe->len; + size_t offset; + int index; + + /* attempt to use fixed buffers without having provided iovecs */ + if (unlikely(!ctx->user_bufs)) + return -EFAULT; + if (unlikely(sqe->buf_index >= ctx->nr_user_bufs)) + return -EFAULT; + + index = array_index_nospec(sqe->buf_index, ctx->sq_entries); + imu = &ctx->user_bufs[index]; + if ((unsigned long) sqe->addr < imu->ubuf || + (unsigned long) sqe->addr + len > imu->ubuf + imu->len) + return -EFAULT; + + /* + * May not be a start of buffer, set size appropriately + * and advance us to the beginning. + */ + offset = (unsigned long) sqe->addr - imu->ubuf; + iov_iter_bvec(iter, rw, imu->bvec, imu->nr_bvecs, offset + len); + if (offset) + iov_iter_advance(iter, offset); + return 0; +} + static int io_import_iovec(struct io_ring_ctx *ctx, int rw, const struct io_uring_sqe *sqe, struct iovec **iovec, struct iov_iter *iter) { void __user *buf = u64_to_user_ptr(sqe->addr); + if (sqe->opcode == IORING_OP_READ_FIXED || + sqe->opcode == IORING_OP_WRITE_FIXED) { + ssize_t ret = io_import_fixed(ctx, rw, sqe, iter); + *iovec = NULL; + return ret; + } + #ifdef CONFIG_COMPAT if (in_compat_syscall()) return compat_import_iovec(rw, buf, sqe->len, UIO_FASTIOV, @@ -805,7 +857,7 @@ static int io_fsync(struct io_kiocb *req, const struct io_uring_sqe *sqe, if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; - if (unlikely(sqe->addr || sqe->ioprio)) + if (unlikely(sqe->addr || sqe->ioprio || sqe->buf_index)) return -EINVAL; if (unlikely(sqe->fsync_flags & ~IORING_FSYNC_DATASYNC)) return -EINVAL; @@ -840,9 +892,19 @@ static int __io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req, ret = io_nop(req, sqe); break; case IORING_OP_READV: + if (unlikely(sqe->buf_index)) + return -EINVAL; ret = io_read(req, sqe, force_nonblock, state); break; case IORING_OP_WRITEV: + if (unlikely(sqe->buf_index)) + return -EINVAL; + ret = io_write(req, sqe, force_nonblock, state); + break; + case IORING_OP_READ_FIXED: + ret = io_read(req, sqe, force_nonblock, state); + break; + case IORING_OP_WRITE_FIXED: ret = io_write(req, sqe, force_nonblock, state); break; case IORING_OP_FSYNC: @@ -865,14 +927,21 @@ static int __io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req, return 0; } +static inline bool io_sqe_needs_user(const struct io_uring_sqe *sqe) +{ + return !(sqe->opcode == IORING_OP_READ_FIXED || + sqe->opcode == IORING_OP_WRITE_FIXED); +} + static void io_sq_wq_submit_work(struct work_struct *work) { struct io_kiocb *req = container_of(work, struct io_kiocb, work); struct sqe_submit *s = &req->submit; u64 user_data = s->sqe->user_data; struct io_ring_ctx *ctx = req->ctx; - mm_segment_t old_fs = get_fs(); struct files_struct *old_files; + mm_segment_t old_fs; + bool needs_user; int ret; /* Ensure we clear previously set forced non-block flag */ @@ -881,19 +950,28 @@ static void io_sq_wq_submit_work(struct work_struct *work) old_files = current->files; current->files = ctx->sqo_files; - if (!mmget_not_zero(ctx->sqo_mm)) { - ret = -EFAULT; - goto err; + /* + * If we're doing IO to fixed buffers, we don't need to get/set + * user context + */ + needs_user = io_sqe_needs_user(s->sqe); + if (needs_user) { + if (!mmget_not_zero(ctx->sqo_mm)) { + ret = -EFAULT; + goto err; + } + use_mm(ctx->sqo_mm); + old_fs = get_fs(); + set_fs(USER_DS); } - use_mm(ctx->sqo_mm); - set_fs(USER_DS); - ret = __io_submit_sqe(ctx, req, s, false, NULL); - set_fs(old_fs); - unuse_mm(ctx->sqo_mm); - mmput(ctx->sqo_mm); + if (needs_user) { + set_fs(old_fs); + unuse_mm(ctx->sqo_mm); + mmput(ctx->sqo_mm); + } err: if (ret) { io_cqring_add_event(ctx, user_data, ret, 0); @@ -1194,6 +1272,14 @@ static void *io_mem_alloc(size_t size) return (void *) __get_free_pages(gfp_flags, get_order(size)); } +static int io_account_mem(struct io_ring_ctx *ctx, unsigned long nr_pages) +{ + if (ctx->user) + return __io_account_mem(ctx->user, nr_pages); + + return 0; +} + static unsigned long ring_pages(unsigned sq_entries, unsigned cq_entries) { struct io_sq_ring *sq_ring; @@ -1207,10 +1293,195 @@ static unsigned long ring_pages(unsigned sq_entries, unsigned cq_entries) return (bytes + PAGE_SIZE - 1) / PAGE_SIZE; } +static int io_sqe_buffer_unregister(struct io_ring_ctx *ctx) +{ + int i, j; + + if (!ctx->user_bufs) + return -ENXIO; + + for (i = 0; i < ctx->sq_entries; i++) { + struct io_mapped_ubuf *imu = &ctx->user_bufs[i]; + + for (j = 0; j < imu->nr_bvecs; j++) + put_page(imu->bvec[j].bv_page); + + io_unaccount_mem(ctx, imu->nr_bvecs); + kfree(imu->bvec); + imu->nr_bvecs = 0; + } + + kfree(ctx->user_bufs); + ctx->user_bufs = NULL; + free_uid(ctx->user); + ctx->user = NULL; + return 0; +} + +static int io_copy_iov(struct io_ring_ctx *ctx, struct iovec *dst, + void __user *arg, unsigned index) +{ + struct iovec __user *src; + +#ifdef CONFIG_COMPAT + if (in_compat_syscall()) { + struct compat_iovec __user *ciovs; + struct compat_iovec ciov; + + ciovs = (struct compat_iovec __user *) arg; + if (copy_from_user(&ciov, &ciovs[index], sizeof(ciov))) + return -EFAULT; + + dst->iov_base = (void __user *) (unsigned long) ciov.iov_base; + dst->iov_len = ciov.iov_len; + return 0; + } +#endif + src = (struct iovec __user *) arg; + if (copy_from_user(dst, &src[index], sizeof(*dst))) + return -EFAULT; + return 0; +} + +static int io_sqe_buffer_register(struct io_ring_ctx *ctx, void __user *arg, + unsigned nr_args) +{ + struct vm_area_struct **vmas = NULL; + struct page **pages = NULL; + int i, j, got_pages = 0; + int ret = -EINVAL; + + if (ctx->user_bufs) + return -EBUSY; + if (!nr_args || nr_args > UIO_MAXIOV) + return -EINVAL; + + ctx->user_bufs = kcalloc(nr_args, sizeof(struct io_mapped_ubuf), + GFP_KERNEL); + if (!ctx->user_bufs) + return -ENOMEM; + + if (!capable(CAP_IPC_LOCK)) + ctx->user = get_uid(current_user()); + + for (i = 0; i < nr_args; i++) { + struct io_mapped_ubuf *imu = &ctx->user_bufs[i]; + unsigned long off, start, end, ubuf; + int pret, nr_pages; + struct iovec iov; + size_t size; + + ret = io_copy_iov(ctx, &iov, arg, i); + if (ret) + break; + + /* + * Don't impose further limits on the size and buffer + * constraints here, we'll -EINVAL later when IO is + * submitted if they are wrong. + */ + ret = -EFAULT; + if (!iov.iov_base) + goto err; + + /* arbitrary limit, but we need something */ + if (iov.iov_len > SZ_1G) + goto err; + + ubuf = (unsigned long) iov.iov_base; + end = (ubuf + iov.iov_len + PAGE_SIZE - 1) >> PAGE_SHIFT; + start = ubuf >> PAGE_SHIFT; + nr_pages = end - start; + + ret = io_account_mem(ctx, nr_pages); + if (ret) + goto err; + + if (!pages || nr_pages > got_pages) { + kfree(vmas); + kfree(pages); + pages = kmalloc_array(nr_pages, sizeof(struct page *), + GFP_KERNEL); + vmas = kmalloc_array(nr_pages, + sizeof(struct vma_area_struct *), + GFP_KERNEL); + if (!pages || !vmas) { + io_unaccount_mem(ctx, nr_pages); + goto err; + } + got_pages = nr_pages; + } + + imu->bvec = kmalloc_array(nr_pages, sizeof(struct bio_vec), + GFP_KERNEL); + if (!imu->bvec) { + io_unaccount_mem(ctx, nr_pages); + goto err; + } + + down_write(¤t->mm->mmap_sem); + pret = get_user_pages_longterm(ubuf, nr_pages, FOLL_WRITE, + pages, vmas); + if (pret == nr_pages) { + /* don't support file backed memory */ + for (j = 0; j < nr_pages; j++) { + struct vm_area_struct *vma = vmas[j]; + + if (vma->vm_file) { + ret = -EOPNOTSUPP; + break; + } + } + } else { + ret = pret < 0 ? pret : -EFAULT; + } + up_write(¤t->mm->mmap_sem); + if (ret) { + /* + * if we did partial map, or found file backed vmas, + * release any pages we did get + */ + if (pret > 0) { + for (j = 0; j < pret; j++) + put_page(pages[j]); + } + io_unaccount_mem(ctx, nr_pages); + goto err; + } + + off = ubuf & ~PAGE_MASK; + size = iov.iov_len; + for (j = 0; j < nr_pages; j++) { + size_t vec_len; + + vec_len = min_t(size_t, size, PAGE_SIZE - off); + imu->bvec[j].bv_page = pages[j]; + imu->bvec[j].bv_len = vec_len; + imu->bvec[j].bv_offset = off; + off = 0; + size -= vec_len; + } + /* store original address for later verification */ + imu->ubuf = ubuf; + imu->len = iov.iov_len; + imu->nr_bvecs = nr_pages; + } + kfree(pages); + kfree(vmas); + ctx->nr_user_bufs = nr_args; + return 0; +err: + kfree(pages); + kfree(vmas); + io_sqe_buffer_unregister(ctx); + return ret; +} + static void io_ring_ctx_free(struct io_ring_ctx *ctx) { destroy_workqueue(ctx->sqo_wq); io_iopoll_reap_events(ctx); + io_sqe_buffer_unregister(ctx); io_mem_free(ctx->sq_ring); io_mem_free(ctx->sq_sqes); @@ -1486,6 +1757,69 @@ SYSCALL_DEFINE2(io_uring_setup, u32, entries, return io_uring_setup(entries, params); } +static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode, + void __user *arg, unsigned nr_args) +{ + int ret; + + /* Drop our initial ref and wait for the ctx to be fully idle */ + percpu_ref_put(&ctx->refs); + percpu_ref_kill(&ctx->refs); + wait_for_completion(&ctx->ctx_done); + + switch (opcode) { + case IORING_REGISTER_BUFFERS: + ret = io_sqe_buffer_register(ctx, arg, nr_args); + break; + case IORING_UNREGISTER_BUFFERS: + ret = -EINVAL; + if (arg || nr_args) + break; + ret = io_sqe_buffer_unregister(ctx); + break; + default: + ret = -EINVAL; + break; + } + + /* bring the ctx back to life */ + reinit_completion(&ctx->ctx_done); + percpu_ref_resurrect(&ctx->refs); + percpu_ref_get(&ctx->refs); + return ret; +} + +SYSCALL_DEFINE4(io_uring_register, unsigned int, fd, unsigned int, opcode, + void __user *, arg, unsigned int, nr_args) +{ + struct io_ring_ctx *ctx; + long ret = -EBADF; + struct fd f; + + f = fdget(fd); + if (!f.file) + return -EBADF; + + ret = -EOPNOTSUPP; + if (f.file->f_op != &io_uring_fops) + goto out_fput; + + ret = -ENXIO; + ctx = f.file->private_data; + if (!percpu_ref_tryget(&ctx->refs)) + goto out_fput; + + ret = -EBUSY; + if (mutex_trylock(&ctx->uring_lock)) { + ret = __io_uring_register(ctx, opcode, arg, nr_args); + mutex_unlock(&ctx->uring_lock); + } + io_ring_drop_ctx_refs(ctx, 1); +out_fput: + fdput(f); + return ret; +} + static int __init io_uring_init(void) { req_cachep = KMEM_CACHE(io_kiocb, SLAB_HWCACHE_ALIGN | SLAB_PANIC); diff --git a/include/linux/sched/user.h b/include/linux/sched/user.h index 39ad98c09c58..c7b5f86b91a1 100644 --- a/include/linux/sched/user.h +++ b/include/linux/sched/user.h @@ -40,7 +40,7 @@ struct user_struct { kuid_t uid; #if defined(CONFIG_PERF_EVENTS) || defined(CONFIG_BPF_SYSCALL) || \ - defined(CONFIG_NET) + defined(CONFIG_NET) || defined(CONFIG_IO_URING) atomic_long_t locked_vm; #endif diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index 3072dbaa7869..3681c05ac538 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -315,6 +315,8 @@ asmlinkage long sys_io_uring_setup(u32 entries, asmlinkage long sys_io_uring_enter(unsigned int fd, u32 to_submit, u32 min_complete, u32 flags, const sigset_t __user *sig, size_t sigsz); +asmlinkage long sys_io_uring_register(unsigned int fd, unsigned int op, + void __user *arg, unsigned int nr_args); /* fs/xattr.c */ asmlinkage long sys_setxattr(const char __user *path, const char __user *name, diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h index 87871e7b7ea7..d346229a1eb0 100644 --- a/include/uapi/asm-generic/unistd.h +++ b/include/uapi/asm-generic/unistd.h @@ -744,9 +744,11 @@ __SYSCALL(__NR_kexec_file_load, sys_kexec_file_load) __SYSCALL(__NR_io_uring_setup, sys_io_uring_setup) #define __NR_io_uring_enter 426 __SYSCALL(__NR_io_uring_enter, sys_io_uring_enter) +#define __NR_io_uring_register 427 +__SYSCALL(__NR_io_uring_register, sys_io_uring_register) #undef __NR_syscalls -#define __NR_syscalls 427 +#define __NR_syscalls 428 /* * 32 bit systems traditionally used different diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h index 4fc5fbd07688..03ce7133c3b2 100644 --- a/include/uapi/linux/io_uring.h +++ b/include/uapi/linux/io_uring.h @@ -29,7 +29,10 @@ struct io_uring_sqe { __u32 fsync_flags; }; __u64 user_data; /* data to be passed back at completion time */ - __u64 __pad2[3]; + union { + __u16 buf_index; /* index into fixed buffers, if used */ + __u64 __pad2[3]; + }; }; /* @@ -41,6 +44,8 @@ struct io_uring_sqe { #define IORING_OP_READV 1 #define IORING_OP_WRITEV 2 #define IORING_OP_FSYNC 3 +#define IORING_OP_READ_FIXED 4 +#define IORING_OP_WRITE_FIXED 5 /* * sqe->fsync_flags @@ -104,4 +109,10 @@ struct io_uring_params { struct io_cqring_offsets cq_off; }; +/* + * io_uring_register(2) opcodes and arguments + */ +#define IORING_REGISTER_BUFFERS 0 +#define IORING_UNREGISTER_BUFFERS 1 + #endif diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c index ee5e523564bb..1bb6604dc19f 100644 --- a/kernel/sys_ni.c +++ b/kernel/sys_ni.c @@ -48,6 +48,7 @@ COND_SYSCALL_COMPAT(io_getevents); COND_SYSCALL_COMPAT(io_pgetevents); COND_SYSCALL(io_uring_setup); COND_SYSCALL(io_uring_enter); +COND_SYSCALL(io_uring_register); /* fs/xattr.c */ From patchwork Mon Jan 28 21:35:33 2019 Content-Type: text/plain; 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Mon, 28 Jan 2019 13:36:06 -0800 (PST) From: Jens Axboe To: linux-aio@kvack.org, linux-block@vger.kernel.org, linux-man@vger.kernel.org, linux-api@vger.kernel.org Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, Jens Axboe Subject: [PATCH 13/18] io_uring: add file set registration Date: Mon, 28 Jan 2019 14:35:33 -0700 Message-Id: <20190128213538.13486-14-axboe@kernel.dk> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190128213538.13486-1-axboe@kernel.dk> References: <20190128213538.13486-1-axboe@kernel.dk> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP We normally have to fget/fput for each IO we do on a file. Even with the batching we do, the cost of the atomic inc/dec of the file usage count adds up. This adds IORING_REGISTER_FILES, and IORING_UNREGISTER_FILES opcodes for the io_uring_register(2) system call. The arguments passed in must be an array of __s32 holding file descriptors, and nr_args should hold the number of file descriptors the application wishes to pin for the duration of the io_uring context (or until IORING_UNREGISTER_FILES is called). When used, the application must set IOSQE_FIXED_FILE in the sqe->flags member. Then, instead of setting sqe->fd to the real fd, it sets sqe->fd to the index in the array passed in to IORING_REGISTER_FILES. Files are automatically unregistered when the io_uring context is torn down. An application need only unregister if it wishes to register a few set of fds. Signed-off-by: Jens Axboe --- fs/io_uring.c | 125 +++++++++++++++++++++++++++++----- include/uapi/linux/io_uring.h | 9 ++- 2 files changed, 116 insertions(+), 18 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 682714d6f217..77993972879b 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -98,6 +98,10 @@ struct io_ring_ctx { struct fasync_struct *cq_fasync; } ____cacheline_aligned_in_smp; + /* if used, fixed file set */ + struct file **user_files; + unsigned nr_user_files; + /* if used, fixed mapped user buffers */ unsigned nr_user_bufs; struct io_mapped_ubuf *user_bufs; @@ -135,6 +139,7 @@ struct io_kiocb { #define REQ_F_FORCE_NONBLOCK 1 /* inline submission attempt */ #define REQ_F_IOPOLL_COMPLETED 2 /* polled IO has completed */ #define REQ_F_IOPOLL_EAGAIN 4 /* submission got EAGAIN */ +#define REQ_F_FIXED_FILE 8 /* ctx owns file */ u64 user_data; u64 res; @@ -357,15 +362,17 @@ static void io_iopoll_complete(struct io_ring_ctx *ctx, unsigned int *nr_events, * Batched puts of the same file, to avoid dirtying the * file usage count multiple times, if avoidable. */ - if (!file) { - file = req->rw.ki_filp; - file_count = 1; - } else if (file == req->rw.ki_filp) { - file_count++; - } else { - fput_many(file, file_count); - file = req->rw.ki_filp; - file_count = 1; + if (!(req->flags & REQ_F_FIXED_FILE)) { + if (!file) { + file = req->rw.ki_filp; + file_count = 1; + } else if (file == req->rw.ki_filp) { + file_count++; + } else { + fput_many(file, file_count); + file = req->rw.ki_filp; + file_count = 1; + } } if (to_free == ARRAY_SIZE(reqs)) @@ -502,13 +509,19 @@ static void kiocb_end_write(struct kiocb *kiocb) } } +static void io_fput(struct io_kiocb *req) +{ + if (!(req->flags & REQ_F_FIXED_FILE)) + fput(req->rw.ki_filp); +} + static void io_complete_rw(struct kiocb *kiocb, long res, long res2) { struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw); kiocb_end_write(kiocb); - fput(kiocb->ki_filp); + io_fput(req); io_cqring_add_event(req->ctx, req->user_data, res, 0); io_free_req(req); } @@ -612,7 +625,14 @@ static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe, struct kiocb *kiocb = &req->rw; int ret; - kiocb->ki_filp = io_file_get(state, sqe->fd); + if (sqe->flags & IOSQE_FIXED_FILE) { + if (unlikely(!ctx->user_files || sqe->fd >= ctx->nr_user_files)) + return -EBADF; + kiocb->ki_filp = ctx->user_files[sqe->fd]; + req->flags |= REQ_F_FIXED_FILE; + } else { + kiocb->ki_filp = io_file_get(state, sqe->fd); + } if (unlikely(!kiocb->ki_filp)) return -EBADF; kiocb->ki_pos = sqe->off; @@ -651,7 +671,8 @@ static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe, } return 0; out_fput: - io_file_put(state, kiocb->ki_filp); + if (!(sqe->flags & IOSQE_FIXED_FILE)) + io_file_put(state, kiocb->ki_filp); return ret; } @@ -769,7 +790,7 @@ static ssize_t io_read(struct io_kiocb *req, const struct io_uring_sqe *sqe, kfree(iovec); out_fput: if (unlikely(ret)) - fput(file); + io_fput(req); return ret; } @@ -824,7 +845,7 @@ static ssize_t io_write(struct io_kiocb *req, const struct io_uring_sqe *sqe, kfree(iovec); out_fput: if (unlikely(ret)) - fput(file); + io_fput(req); return ret; } @@ -862,14 +883,23 @@ static int io_fsync(struct io_kiocb *req, const struct io_uring_sqe *sqe, if (unlikely(sqe->fsync_flags & ~IORING_FSYNC_DATASYNC)) return -EINVAL; - file = fget(sqe->fd); + if (sqe->flags & IOSQE_FIXED_FILE) { + if (unlikely(!ctx->user_files || sqe->fd >= ctx->nr_user_files)) + return -EBADF; + file = ctx->user_files[sqe->fd]; + } else { + file = fget(sqe->fd); + } + if (unlikely(!file)) return -EBADF; ret = vfs_fsync_range(file, sqe->off, end > 0 ? end : LLONG_MAX, sqe->fsync_flags & IORING_FSYNC_DATASYNC); - fput(file); + if (!(sqe->flags & IOSQE_FIXED_FILE)) + fput(file); + io_cqring_add_event(ctx, sqe->user_data, ret, 0); io_free_req(req); return 0; @@ -987,7 +1017,7 @@ static int io_submit_sqe(struct io_ring_ctx *ctx, struct sqe_submit *s, ssize_t ret; /* enforce forwards compatibility on users */ - if (unlikely(s->sqe->flags)) + if (unlikely(s->sqe->flags & ~IOSQE_FIXED_FILE)) return -EINVAL; req = io_get_req(ctx, state); @@ -1195,6 +1225,57 @@ static int __io_uring_enter(struct io_ring_ctx *ctx, unsigned to_submit, return submitted ? submitted : ret; } +static int io_sqe_files_unregister(struct io_ring_ctx *ctx) +{ + int i; + + if (!ctx->user_files) + return -ENXIO; + + for (i = 0; i < ctx->nr_user_files; i++) + fput(ctx->user_files[i]); + + kfree(ctx->user_files); + ctx->user_files = NULL; + ctx->nr_user_files = 0; + return 0; +} + +static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg, + unsigned nr_args) +{ + __s32 __user *fds = (__s32 __user *) arg; + int fd, i, ret = 0; + + if (ctx->user_files) + return -EBUSY; + if (!nr_args) + return -EINVAL; + + ctx->user_files = kcalloc(nr_args, sizeof(struct file *), GFP_KERNEL); + if (!ctx->user_files) + return -ENOMEM; + + for (i = 0; i < nr_args; i++) { + ret = -EFAULT; + if (copy_from_user(&fd, &fds[i], sizeof(fd))) + break; + + ctx->user_files[i] = fget(fd); + + ret = -EBADF; + if (!ctx->user_files[i]) + break; + ctx->nr_user_files++; + ret = 0; + } + + if (ret) + io_sqe_files_unregister(ctx); + + return ret; +} + static int io_sq_offload_start(struct io_ring_ctx *ctx) { int ret; @@ -1482,6 +1563,7 @@ static void io_ring_ctx_free(struct io_ring_ctx *ctx) destroy_workqueue(ctx->sqo_wq); io_iopoll_reap_events(ctx); io_sqe_buffer_unregister(ctx); + io_sqe_files_unregister(ctx); io_mem_free(ctx->sq_ring); io_mem_free(ctx->sq_sqes); @@ -1777,6 +1859,15 @@ static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode, break; ret = io_sqe_buffer_unregister(ctx); break; + case IORING_REGISTER_FILES: + ret = io_sqe_files_register(ctx, arg, nr_args); + break; + case IORING_UNREGISTER_FILES: + ret = -EINVAL; + if (arg || nr_args) + break; + ret = io_sqe_files_unregister(ctx); + break; default: ret = -EINVAL; break; diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h index 03ce7133c3b2..8323320077ec 100644 --- a/include/uapi/linux/io_uring.h +++ b/include/uapi/linux/io_uring.h @@ -18,7 +18,7 @@ */ struct io_uring_sqe { __u8 opcode; /* type of operation for this sqe */ - __u8 flags; /* as of now unused */ + __u8 flags; /* IOSQE_ flags */ __u16 ioprio; /* ioprio for the request */ __s32 fd; /* file descriptor to do IO on */ __u64 off; /* offset into file */ @@ -35,6 +35,11 @@ struct io_uring_sqe { }; }; +/* + * sqe->flags + */ +#define IOSQE_FIXED_FILE (1 << 0) /* use fixed fileset */ + /* * io_uring_setup() flags */ @@ -114,5 +119,7 @@ struct io_uring_params { */ #define IORING_REGISTER_BUFFERS 0 #define IORING_UNREGISTER_BUFFERS 1 +#define IORING_REGISTER_FILES 2 +#define IORING_UNREGISTER_FILES 3 #endif From patchwork Mon Jan 28 21:35:34 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Axboe X-Patchwork-Id: 10784881 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 508A0139A for ; Mon, 28 Jan 2019 21:36:12 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3F3F62B51A for ; 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Mon, 28 Jan 2019 13:36:09 -0800 (PST) Received: from localhost.localdomain ([216.160.245.98]) by smtp.gmail.com with ESMTPSA id u25sm13782077iob.23.2019.01.28.13.36.07 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 28 Jan 2019 13:36:08 -0800 (PST) From: Jens Axboe To: linux-aio@kvack.org, linux-block@vger.kernel.org, linux-man@vger.kernel.org, linux-api@vger.kernel.org Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, Jens Axboe Subject: [PATCH 14/18] io_uring: add submission polling Date: Mon, 28 Jan 2019 14:35:34 -0700 Message-Id: <20190128213538.13486-15-axboe@kernel.dk> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190128213538.13486-1-axboe@kernel.dk> References: <20190128213538.13486-1-axboe@kernel.dk> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This enables an application to do IO, without ever entering the kernel. By using the SQ ring to fill in new sqes and watching for completions on the CQ ring, we can submit and reap IOs without doing a single system call. The kernel side thread will poll for new submissions, and in case of HIPRI/polled IO, it'll also poll for completions. By default, we allow 1 second of active spinning. This can by changed by passing in a different grace period at io_uring_register(2) time. If the thread exceeds this idle time without having any work to do, it will set: sq_ring->flags |= IORING_SQ_NEED_WAKEUP. The application will have to call io_uring_enter() to start things back up again. If IO is kept busy, that will never be needed. Basically an application that has this feature enabled will guard it's io_uring_enter(2) call with: read_barrier(); if (*sq_ring->flags & IORING_SQ_NEED_WAKEUP) io_uring_enter(fd, 0, 0, IORING_ENTER_SQ_WAKEUP); instead of calling it unconditionally. Signed-off-by: Jens Axboe --- fs/io_uring.c | 232 +++++++++++++++++++++++++++++++++- include/uapi/linux/io_uring.h | 12 +- 2 files changed, 237 insertions(+), 7 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 77993972879b..34e786eb2e2d 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -24,6 +24,7 @@ #include #include #include +#include #include #include #include @@ -79,14 +80,16 @@ struct io_ring_ctx { unsigned cached_sq_head; unsigned sq_entries; unsigned sq_mask; - unsigned sq_thread_cpu; + unsigned sq_thread_idle; struct io_uring_sqe *sq_sqes; } ____cacheline_aligned_in_smp; /* IO offload */ struct workqueue_struct *sqo_wq; + struct task_struct *sqo_thread; /* if using sq thread polling */ struct mm_struct *sqo_mm; struct files_struct *sqo_files; + wait_queue_head_t sqo_wait; struct { /* CQ ring */ @@ -262,6 +265,8 @@ static void __io_cqring_add_event(struct io_ring_ctx *ctx, u64 ki_user_data, if (waitqueue_active(&ctx->wait)) wake_up(&ctx->wait); + if (waitqueue_active(&ctx->sqo_wait)) + wake_up(&ctx->sqo_wait); } static void io_cqring_add_event(struct io_ring_ctx *ctx, u64 ki_user_data, @@ -1113,6 +1118,168 @@ static bool io_get_sqring(struct io_ring_ctx *ctx, struct sqe_submit *s) return false; } +static int io_submit_sqes(struct io_ring_ctx *ctx, struct sqe_submit *sqes, + unsigned int nr, bool mm_fault) +{ + struct io_submit_state state, *statep = NULL; + int ret, i, submitted = 0; + + if (nr > IO_PLUG_THRESHOLD) { + io_submit_state_start(&state, ctx, nr); + statep = &state; + } + + for (i = 0; i < nr; i++) { + if (unlikely(mm_fault)) + ret = -EFAULT; + else + ret = io_submit_sqe(ctx, &sqes[i], statep); + if (!ret) { + submitted++; + continue; + } + + io_cqring_add_event(ctx, sqes[i].sqe->user_data, ret, 0); + } + + if (statep) + io_submit_state_end(&state); + + return submitted; +} + +static int io_sq_thread(void *data) +{ + struct sqe_submit sqes[IO_IOPOLL_BATCH]; + struct io_ring_ctx *ctx = data; + struct mm_struct *cur_mm = NULL; + struct files_struct *old_files; + mm_segment_t old_fs; + DEFINE_WAIT(wait); + unsigned inflight; + unsigned long timeout; + + old_files = current->files; + current->files = ctx->sqo_files; + + old_fs = get_fs(); + set_fs(USER_DS); + + timeout = inflight = 0; + while (!kthread_should_stop()) { + bool all_fixed, mm_fault = false; + int i; + + if (inflight) { + unsigned nr_events = 0; + + if (ctx->flags & IORING_SETUP_IOPOLL) { + /* + * We disallow the app entering submit/complete + * with polling, so no need to lock the ring. + */ + io_iopoll_check(ctx, &nr_events, 0); + } else { + /* + * Normal IO, just pretend everything completed. + * We don't have to poll completions for that. + */ + nr_events = inflight; + } + + inflight -= nr_events; + if (!inflight) + timeout = jiffies + ctx->sq_thread_idle; + } + + if (!io_get_sqring(ctx, &sqes[0])) { + /* + * We're polling. If we're within the defined idle + * period, then let us spin without work before going + * to sleep. + */ + if (inflight || !time_after(jiffies, timeout)) { + cpu_relax(); + continue; + } + + /* + * Drop cur_mm before scheduling, we can't hold it for + * long periods (or over schedule()). Do this before + * adding ourselves to the waitqueue, as the unuse/drop + * may sleep. + */ + if (cur_mm) { + unuse_mm(cur_mm); + mmput(cur_mm); + cur_mm = NULL; + } + + prepare_to_wait(&ctx->sqo_wait, &wait, + TASK_INTERRUPTIBLE); + + /* Tell userspace we may need a wakeup call */ + ctx->sq_ring->flags |= IORING_SQ_NEED_WAKEUP; + smp_wmb(); + + if (!io_get_sqring(ctx, &sqes[0])) { + if (kthread_should_park()) + kthread_parkme(); + if (kthread_should_stop()) { + finish_wait(&ctx->sqo_wait, &wait); + break; + } + if (signal_pending(current)) + flush_signals(current); + schedule(); + finish_wait(&ctx->sqo_wait, &wait); + + ctx->sq_ring->flags &= ~IORING_SQ_NEED_WAKEUP; + smp_wmb(); + continue; + } + finish_wait(&ctx->sqo_wait, &wait); + + ctx->sq_ring->flags &= ~IORING_SQ_NEED_WAKEUP; + smp_wmb(); + } + + i = 0; + all_fixed = true; + do { + if (all_fixed && io_sqe_needs_user(sqes[i].sqe)) + all_fixed = false; + + i++; + if (i == ARRAY_SIZE(sqes)) + break; + } while (io_get_sqring(ctx, &sqes[i])); + + io_commit_sqring(ctx); + + /* Unless all new commands are FIXED regions, grab mm */ + if (!all_fixed && !cur_mm) { + mm_fault = !mmget_not_zero(ctx->sqo_mm); + if (!mm_fault) { + use_mm(ctx->sqo_mm); + cur_mm = ctx->sqo_mm; + } + } + + inflight += io_submit_sqes(ctx, sqes, i, mm_fault); + } + + io_iopoll_reap_events(ctx); + + current->files = old_files; + set_fs(old_fs); + if (cur_mm) { + unuse_mm(cur_mm); + mmput(cur_mm); + } + return 0; +} + static int io_ring_submit(struct io_ring_ctx *ctx, unsigned int to_submit) { struct io_submit_state state, *statep = NULL; @@ -1198,6 +1365,17 @@ static int __io_uring_enter(struct io_ring_ctx *ctx, unsigned to_submit, { int submitted, ret; + /* + * For SQ polling, the thread will do all submissions and completions. + * Just return the requested submit count, and wake the thread if + * we were asked to. + */ + if (ctx->flags & IORING_SETUP_SQPOLL) { + if (flags & IORING_ENTER_SQ_WAKEUP) + wake_up(&ctx->sqo_wait); + return to_submit; + } + submitted = ret = 0; if (to_submit) { submitted = io_ring_submit(ctx, to_submit); @@ -1276,10 +1454,12 @@ static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg, return ret; } -static int io_sq_offload_start(struct io_ring_ctx *ctx) +static int io_sq_offload_start(struct io_ring_ctx *ctx, + struct io_uring_params *p) { int ret; + init_waitqueue_head(&ctx->sqo_wait); ctx->sqo_mm = current->mm; /* @@ -1292,6 +1472,34 @@ static int io_sq_offload_start(struct io_ring_ctx *ctx) if (!ctx->sqo_files) goto err; + ctx->sq_thread_idle = msecs_to_jiffies(p->sq_thread_idle); + if (!ctx->sq_thread_idle) + ctx->sq_thread_idle = HZ; + + if (ctx->flags & IORING_SETUP_SQPOLL) { + if (p->flags & IORING_SETUP_SQ_AFF) { + int cpu; + + cpu = array_index_nospec(p->sq_thread_cpu, NR_CPUS); + ctx->sqo_thread = kthread_create_on_cpu(io_sq_thread, + ctx, cpu, + "io_uring-sq"); + } else { + ctx->sqo_thread = kthread_create(io_sq_thread, ctx, + "io_uring-sq"); + } + if (IS_ERR(ctx->sqo_thread)) { + ret = PTR_ERR(ctx->sqo_thread); + ctx->sqo_thread = NULL; + goto err; + } + wake_up_process(ctx->sqo_thread); + } else if (p->flags & IORING_SETUP_SQ_AFF) { + /* Can't have SQ_AFF without SQPOLL */ + ret = -EINVAL; + goto err; + } + /* Do QD, or 2 * CPUS, whatever is smallest */ ctx->sqo_wq = alloc_workqueue("io_ring-wq", WQ_UNBOUND | WQ_FREEZABLE, min(ctx->sq_entries - 1, 2 * num_online_cpus())); @@ -1302,6 +1510,11 @@ static int io_sq_offload_start(struct io_ring_ctx *ctx) return 0; err: + if (ctx->sqo_thread) { + kthread_park(ctx->sqo_thread); + kthread_stop(ctx->sqo_thread); + ctx->sqo_thread = NULL; + } if (ctx->sqo_files) ctx->sqo_files = NULL; ctx->sqo_mm = NULL; @@ -1560,8 +1773,13 @@ static int io_sqe_buffer_register(struct io_ring_ctx *ctx, void __user *arg, static void io_ring_ctx_free(struct io_ring_ctx *ctx) { + if (ctx->sqo_thread) { + kthread_park(ctx->sqo_thread); + kthread_stop(ctx->sqo_thread); + } destroy_workqueue(ctx->sqo_wq); - io_iopoll_reap_events(ctx); + if (!(ctx->flags & IORING_SETUP_SQPOLL)) + io_iopoll_reap_events(ctx); io_sqe_buffer_unregister(ctx); io_sqe_files_unregister(ctx); @@ -1602,7 +1820,8 @@ static void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx) percpu_ref_kill(&ctx->refs); mutex_unlock(&ctx->uring_lock); - io_iopoll_reap_events(ctx); + if (!(ctx->flags & IORING_SETUP_SQPOLL)) + io_iopoll_reap_events(ctx); wait_for_completion(&ctx->ctx_done); io_ring_ctx_free(ctx); } @@ -1771,7 +1990,7 @@ static int io_uring_create(unsigned entries, struct io_uring_params *p) if (ret) goto err; - ret = io_sq_offload_start(ctx); + ret = io_sq_offload_start(ctx, p); if (ret) goto err; @@ -1820,7 +2039,8 @@ static long io_uring_setup(u32 entries, struct io_uring_params __user *params) return -EINVAL; } - if (p.flags & ~IORING_SETUP_IOPOLL) + if (p.flags & ~(IORING_SETUP_IOPOLL | IORING_SETUP_SQPOLL | + IORING_SETUP_SQ_AFF)) return -EINVAL; ret = io_uring_create(entries, &p); diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h index 8323320077ec..cb3592d618fe 100644 --- a/include/uapi/linux/io_uring.h +++ b/include/uapi/linux/io_uring.h @@ -44,6 +44,8 @@ struct io_uring_sqe { * io_uring_setup() flags */ #define IORING_SETUP_IOPOLL (1 << 0) /* io_context is polled */ +#define IORING_SETUP_SQPOLL (1 << 1) /* SQ poll thread */ +#define IORING_SETUP_SQ_AFF (1 << 2) /* sq_thread_cpu is valid */ #define IORING_OP_NOP 0 #define IORING_OP_READV 1 @@ -87,6 +89,11 @@ struct io_sqring_offsets { __u32 resv[3]; }; +/* + * sq_ring->flags + */ +#define IORING_SQ_NEED_WAKEUP (1 << 0) /* needs io_uring_enter wakeup */ + struct io_cqring_offsets { __u32 head; __u32 tail; @@ -101,6 +108,7 @@ struct io_cqring_offsets { * io_uring_enter(2) flags */ #define IORING_ENTER_GETEVENTS (1 << 0) +#define IORING_ENTER_SQ_WAKEUP (1 << 1) /* * Passed in for io_uring_setup(2). Copied back with updated info on success @@ -109,7 +117,9 @@ struct io_uring_params { __u32 sq_entries; __u32 cq_entries; __u32 flags; - __u16 resv[10]; + __u16 sq_thread_cpu; + __u16 sq_thread_idle; + __u16 resv[8]; struct io_sqring_offsets sq_off; struct io_cqring_offsets cq_off; }; From patchwork Mon Jan 28 21:35:35 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Axboe X-Patchwork-Id: 10784883 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 006D01390 for ; Mon, 28 Jan 2019 21:36:13 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id E407F2B51A for ; Mon, 28 Jan 2019 21:36:12 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id D89332B552; Mon, 28 Jan 2019 21:36:12 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 8779B2B51A for ; Mon, 28 Jan 2019 21:36:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728357AbfA1VgM (ORCPT ); Mon, 28 Jan 2019 16:36:12 -0500 Received: from mail-it1-f194.google.com ([209.85.166.194]:52441 "EHLO mail-it1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728332AbfA1VgL (ORCPT ); Mon, 28 Jan 2019 16:36:11 -0500 Received: by mail-it1-f194.google.com with SMTP id d11so935961itf.2 for ; Mon, 28 Jan 2019 13:36:11 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=SyN4FVJHSbniTFclb7EwO9EKb7bx5qQceMJrgjYtwI4=; b=ytrEhMjnedgUQ4r39gRu8mcnn1yXOTAl691b0XYjHcf+0GPtd2pqysYYa6wQW/Bojl q2dOPRfkMLEFK539mHpmB/lPglgXSkedo5vCV3sMaOchGJa3Hkm4WcB9IDxCcLnaXq8X j38INjLmLBR11JhIlFRZxwHTVSxPWcD8zVuzbEP34oWyF+MTwOMHIo9SJtfW+nlpOne5 JVsJT95AfQcqeCNdFXiSZq/R8D+vytGDmN+yyh9f2cubUmkAx4PkkeLZMpCCZh2d4Brj L2mbMajHSBtcs9LH9zFuyxdB6jzpFj33g+PL/SmmpDEX4P4NN5oLCwQloz9ktU1Sp64t ixNg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=SyN4FVJHSbniTFclb7EwO9EKb7bx5qQceMJrgjYtwI4=; b=IaIjH4J1RXU9Bmy9s6ZSWyCYu3tjilqs+V6ITHq8Sd44GZmRDINtQI+bKyR2uDb6Fa L9M95E9+lBiQqeyuTATDfmEGP8Z6/MN9n4ZiEA/beQcTdbhypeIp7eE0SmzXf4F/j91y wrOqiK6GVK2O4+HcxjHCdqXWTDj7uVi8RU3fKm9e6JuzW/MeTzoKz2jGi2/u9oFsgxsY tYs0eV+Jdt0BWq//EDMUpx1EJLkO0nQ3iKBScOM40YOsdaqZ54E1FVWQHONDTMREN6e7 gXZEM3k7S1JYj/hw3qBrFfOQYEcsgdXQ0Go8Rl0754x1tFW4RC+Kf4HH947aZzNJUgFs 997g== X-Gm-Message-State: AJcUukcfzfh8PmzcyB0i8vQ8NdQVI/vzxHfUfZm/+yJv3BvOQzaOyyvW 3X4WIks3ji3ul2kF3vaLmNRkoA== X-Google-Smtp-Source: ALg8bN6gslaE0Bixl/KsFJ1/Eq/MD6/fgjyIeYnXhE/sieU9Zh9rsLuloGkg6WH6vKl9fcc+5mYmxg== X-Received: by 2002:a24:c8d7:: with SMTP id w206mr11765338itf.56.1548711370992; Mon, 28 Jan 2019 13:36:10 -0800 (PST) Received: from localhost.localdomain ([216.160.245.98]) by smtp.gmail.com with ESMTPSA id u25sm13782077iob.23.2019.01.28.13.36.09 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 28 Jan 2019 13:36:09 -0800 (PST) From: Jens Axboe To: linux-aio@kvack.org, linux-block@vger.kernel.org, linux-man@vger.kernel.org, linux-api@vger.kernel.org Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, Jens Axboe Subject: [PATCH 15/18] io_uring: add io_kiocb ref count Date: Mon, 28 Jan 2019 14:35:35 -0700 Message-Id: <20190128213538.13486-16-axboe@kernel.dk> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190128213538.13486-1-axboe@kernel.dk> References: <20190128213538.13486-1-axboe@kernel.dk> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP We'll use this for the POLL implementation. Regular requests will NOT be using references, so initialize it to 0. Any real use of the io_kiocb ref will initialize it to at least 2. Signed-off-by: Jens Axboe Reviewed-by: Christoph Hellwig --- fs/io_uring.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 34e786eb2e2d..71bf890e25f2 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -139,6 +139,7 @@ struct io_kiocb { struct io_ring_ctx *ctx; struct list_head list; unsigned int flags; + refcount_t refs; #define REQ_F_FORCE_NONBLOCK 1 /* inline submission attempt */ #define REQ_F_IOPOLL_COMPLETED 2 /* polled IO has completed */ #define REQ_F_IOPOLL_EAGAIN 4 /* submission got EAGAIN */ @@ -319,6 +320,7 @@ static struct io_kiocb *io_get_req(struct io_ring_ctx *ctx, if (req) { req->ctx = ctx; req->flags = 0; + refcount_set(&req->refs, 0); return req; } @@ -338,8 +340,10 @@ static void io_free_req_many(struct io_ring_ctx *ctx, void **reqs, int *nr) static void io_free_req(struct io_kiocb *req) { - io_ring_drop_ctx_refs(req->ctx, 1); - kmem_cache_free(req_cachep, req); + if (!refcount_read(&req->refs) || refcount_dec_and_test(&req->refs)) { + io_ring_drop_ctx_refs(req->ctx, 1); + kmem_cache_free(req_cachep, req); + } } /* From patchwork Mon Jan 28 21:35:36 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Axboe X-Patchwork-Id: 10784885 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 93719139A for ; Mon, 28 Jan 2019 21:36:16 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 81AA62B51A for ; Mon, 28 Jan 2019 21:36:16 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 75EFB2B552; Mon, 28 Jan 2019 21:36:16 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id AD3902B51A for ; 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Mon, 28 Jan 2019 13:36:12 -0800 (PST) From: Jens Axboe To: linux-aio@kvack.org, linux-block@vger.kernel.org, linux-man@vger.kernel.org, linux-api@vger.kernel.org Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, Jens Axboe Subject: [PATCH 16/18] io_uring: add support for IORING_OP_POLL Date: Mon, 28 Jan 2019 14:35:36 -0700 Message-Id: <20190128213538.13486-17-axboe@kernel.dk> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190128213538.13486-1-axboe@kernel.dk> References: <20190128213538.13486-1-axboe@kernel.dk> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This is basically a direct port of bfe4037e722e, which implements a one-shot poll command through aio. Description below is based on that commit as well. However, instead of adding a POLL command and relying on io_cancel(2) to remove it, we mimic the epoll(2) interface of having a command to add a poll notification, IORING_OP_POLL_ADD, and one to remove it again, IORING_OP_POLL_REMOVE. To poll for a file descriptor the application should submit an sqe of type IORING_OP_POLL. It will poll the fd for the events specified in the poll_events field. Unlike poll or epoll without EPOLLONESHOT this interface always works in one shot mode, that is once the sqe is completed, it will have to be resubmitted. Based-on-code-from: Christoph Hellwig Signed-off-by: Jens Axboe --- fs/io_uring.c | 245 ++++++++++++++++++++++++++++++++++ include/uapi/linux/io_uring.h | 3 + 2 files changed, 248 insertions(+) diff --git a/fs/io_uring.c b/fs/io_uring.c index 71bf890e25f2..13e9bb0ce44e 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -122,6 +122,7 @@ struct io_ring_ctx { spinlock_t completion_lock; bool poll_multi_file; struct list_head poll_list; + struct list_head cancel_list; } ____cacheline_aligned_in_smp; }; @@ -130,9 +131,19 @@ struct sqe_submit { unsigned index; }; +struct io_poll_iocb { + struct file *file; + struct wait_queue_head *head; + __poll_t events; + bool woken; + bool canceled; + struct wait_queue_entry wait; +}; + struct io_kiocb { union { struct kiocb rw; + struct io_poll_iocb poll; struct sqe_submit submit; }; @@ -204,6 +215,7 @@ static struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p) init_waitqueue_head(&ctx->wait); spin_lock_init(&ctx->completion_lock); INIT_LIST_HEAD(&ctx->poll_list); + INIT_LIST_HEAD(&ctx->cancel_list); return ctx; } @@ -914,6 +926,232 @@ static int io_fsync(struct io_kiocb *req, const struct io_uring_sqe *sqe, return 0; } +static void io_poll_remove_one(struct io_kiocb *req) +{ + struct io_poll_iocb *poll = &req->poll; + + spin_lock(&poll->head->lock); + WRITE_ONCE(poll->canceled, true); + if (!list_empty(&poll->wait.entry)) { + list_del_init(&poll->wait.entry); + queue_work(req->ctx->sqo_wq, &req->work); + } + spin_unlock(&poll->head->lock); + + list_del_init(&req->list); +} + +static void io_poll_remove_all(struct io_ring_ctx *ctx) +{ + struct io_kiocb *req; + + spin_lock_irq(&ctx->completion_lock); + while (!list_empty(&ctx->cancel_list)) { + req = list_first_entry(&ctx->cancel_list, struct io_kiocb,list); + io_poll_remove_one(req); + } + spin_unlock_irq(&ctx->completion_lock); +} + +/* + * Find a running poll command that matches one specified in sqe->addr, + * and remove it if found. + */ +static int io_poll_remove(struct io_kiocb *req, const struct io_uring_sqe *sqe) +{ + struct io_ring_ctx *ctx = req->ctx; + struct io_kiocb *poll_req, *next; + int ret = -ENOENT; + + if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) + return -EINVAL; + if (sqe->ioprio || sqe->off || sqe->len || sqe->buf_index || + sqe->poll_events) + return -EINVAL; + + spin_lock_irq(&ctx->completion_lock); + list_for_each_entry_safe(poll_req, next, &ctx->cancel_list, list) { + if (sqe->addr == poll_req->user_data) { + io_poll_remove_one(poll_req); + ret = 0; + break; + } + } + spin_unlock_irq(&ctx->completion_lock); + + io_cqring_add_event(req->ctx, sqe->user_data, ret, 0); + io_free_req(req); + return 0; +} + +static void io_poll_complete(struct io_kiocb *req, __poll_t mask) +{ + io_cqring_add_event(req->ctx, req->user_data, mangle_poll(mask), 0); + io_fput(req); + io_free_req(req); +} + +static void io_poll_complete_work(struct work_struct *work) +{ + struct io_kiocb *req = container_of(work, struct io_kiocb, work); + struct io_poll_iocb *poll = &req->poll; + struct poll_table_struct pt = { ._key = poll->events }; + struct io_ring_ctx *ctx = req->ctx; + __poll_t mask = 0; + + if (!READ_ONCE(poll->canceled)) + mask = vfs_poll(poll->file, &pt) & poll->events; + + /* + * Note that ->ki_cancel callers also delete iocb from active_reqs after + * calling ->ki_cancel. We need the ctx_lock roundtrip here to + * synchronize with them. In the cancellation case the list_del_init + * itself is not actually needed, but harmless so we keep it in to + * avoid further branches in the fast path. + */ + spin_lock_irq(&ctx->completion_lock); + if (!mask && !READ_ONCE(poll->canceled)) { + add_wait_queue(poll->head, &poll->wait); + spin_unlock_irq(&ctx->completion_lock); + return; + } + list_del_init(&req->list); + spin_unlock_irq(&ctx->completion_lock); + + io_poll_complete(req, mask); +} + +static int io_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync, + void *key) +{ + struct io_poll_iocb *poll = container_of(wait, struct io_poll_iocb, + wait); + struct io_kiocb *req = container_of(poll, struct io_kiocb, poll); + struct io_ring_ctx *ctx = req->ctx; + __poll_t mask = key_to_poll(key); + + poll->woken = true; + + /* for instances that support it check for an event match first: */ + if (mask) { + if (!(mask & poll->events)) + return 0; + + /* try to complete the iocb inline if we can: */ + if (spin_trylock(&ctx->completion_lock)) { + list_del(&req->list); + spin_unlock(&ctx->completion_lock); + + list_del_init(&poll->wait.entry); + io_poll_complete(req, mask); + return 1; + } + } + + list_del_init(&poll->wait.entry); + queue_work(ctx->sqo_wq, &req->work); + return 1; +} + +struct io_poll_table { + struct poll_table_struct pt; + struct io_kiocb *req; + int error; +}; + +static void io_poll_queue_proc(struct file *file, struct wait_queue_head *head, + struct poll_table_struct *p) +{ + struct io_poll_table *pt = container_of(p, struct io_poll_table, pt); + + if (unlikely(pt->req->poll.head)) { + pt->error = -EINVAL; + return; + } + + pt->error = 0; + pt->req->poll.head = head; + add_wait_queue(head, &pt->req->poll.wait); +} + +static int io_poll_add(struct io_kiocb *req, const struct io_uring_sqe *sqe) +{ + struct io_poll_iocb *poll = &req->poll; + struct io_ring_ctx *ctx = req->ctx; + struct io_poll_table ipt; + __poll_t mask; + + if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) + return -EINVAL; + if (sqe->addr || sqe->ioprio || sqe->off || sqe->len || sqe->buf_index) + return -EINVAL; + + INIT_WORK(&req->work, io_poll_complete_work); + poll->events = demangle_poll(sqe->poll_events) | EPOLLERR | EPOLLHUP; + + if (sqe->flags & IOSQE_FIXED_FILE) { + if (unlikely(!ctx->user_files || sqe->fd >= ctx->nr_user_files)) + return -EBADF; + poll->file = ctx->user_files[sqe->fd]; + req->flags |= REQ_F_FIXED_FILE; + } else { + poll->file = fget(sqe->fd); + } + if (unlikely(!poll->file)) + return -EBADF; + + poll->head = NULL; + poll->woken = false; + poll->canceled = false; + + ipt.pt._qproc = io_poll_queue_proc; + ipt.pt._key = poll->events; + ipt.req = req; + ipt.error = -EINVAL; /* same as no support for IOCB_CMD_POLL */ + + /* initialized the list so that we can do list_empty checks */ + INIT_LIST_HEAD(&poll->wait.entry); + init_waitqueue_func_entry(&poll->wait, io_poll_wake); + + /* one for removal from waitqueue, one for this function */ + refcount_set(&req->refs, 2); + + mask = vfs_poll(poll->file, &ipt.pt) & poll->events; + if (unlikely(!poll->head)) { + /* we did not manage to set up a waitqueue, done */ + goto out; + } + + spin_lock_irq(&ctx->completion_lock); + spin_lock(&poll->head->lock); + if (poll->woken) { + /* wake_up context handles the rest */ + mask = 0; + ipt.error = 0; + } else if (mask || ipt.error) { + /* if we get an error or a mask we are done */ + WARN_ON_ONCE(list_empty(&poll->wait.entry)); + list_del_init(&poll->wait.entry); + } else { + /* actually waiting for an event */ + list_add_tail(&req->list, &ctx->cancel_list); + } + spin_unlock(&poll->head->lock); + spin_unlock_irq(&ctx->completion_lock); + +out: + if (unlikely(ipt.error)) { + if (!(sqe->flags & IOSQE_FIXED_FILE)) + fput(poll->file); + return ipt.error; + } + + if (mask) + io_poll_complete(req, mask); + io_free_req(req); + return 0; +} + static int __io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req, struct sqe_submit *s, bool force_nonblock, struct io_submit_state *state) @@ -949,6 +1187,12 @@ static int __io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req, case IORING_OP_FSYNC: ret = io_fsync(req, sqe, force_nonblock); break; + case IORING_OP_POLL_ADD: + ret = io_poll_add(req, sqe); + break; + case IORING_OP_POLL_REMOVE: + ret = io_poll_remove(req, sqe); + break; default: ret = -EINVAL; break; @@ -1824,6 +2068,7 @@ static void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx) percpu_ref_kill(&ctx->refs); mutex_unlock(&ctx->uring_lock); + io_poll_remove_all(ctx); if (!(ctx->flags & IORING_SETUP_SQPOLL)) io_iopoll_reap_events(ctx); wait_for_completion(&ctx->ctx_done); diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h index cb3592d618fe..39d3d3336dce 100644 --- a/include/uapi/linux/io_uring.h +++ b/include/uapi/linux/io_uring.h @@ -27,6 +27,7 @@ struct io_uring_sqe { union { __kernel_rwf_t rw_flags; __u32 fsync_flags; + __u16 poll_events; }; __u64 user_data; /* data to be passed back at completion time */ union { @@ -53,6 +54,8 @@ struct io_uring_sqe { #define IORING_OP_FSYNC 3 #define IORING_OP_READ_FIXED 4 #define IORING_OP_WRITE_FIXED 5 +#define IORING_OP_POLL_ADD 6 +#define IORING_OP_POLL_REMOVE 7 /* * sqe->fsync_flags From patchwork Mon Jan 28 21:35:37 2019 Content-Type: text/plain; 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Mon, 28 Jan 2019 13:36:14 -0800 (PST) From: Jens Axboe To: linux-aio@kvack.org, linux-block@vger.kernel.org, linux-man@vger.kernel.org, linux-api@vger.kernel.org Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, Jens Axboe Subject: [PATCH 17/18] io_uring: allow workqueue item to handle multiple buffered requests Date: Mon, 28 Jan 2019 14:35:37 -0700 Message-Id: <20190128213538.13486-18-axboe@kernel.dk> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190128213538.13486-1-axboe@kernel.dk> References: <20190128213538.13486-1-axboe@kernel.dk> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Right now we punt any buffered request that ends up triggering an -EAGAIN to an async workqueue. This works fine in terms of providing async execution of them, but it also can create quite a lot of work queue items. For sequentially buffered IO, it's advantageous to serialize the issue of them. For reads, the first one will trigger a read-ahead, and subsequent request merely end up waiting on later pages to complete. For writes, devices usually respond better to streamed sequential writes. Add state to track the last buffered request we punted to a work queue, and if the next one is sequential to the previous, attempt to get the previous work item to handle it. We limit the number of sequential add-ons to the a multiple (8) of the max read-ahead size of the file. This should be a good number for both reads and wries, as it defines the max IO size the device can do directly. This drastically cuts down on the number of context switches we need to handle buffered sequential IO, and a basic test case of copying a big file with io_uring sees a 5x speedup. Signed-off-by: Jens Axboe --- fs/io_uring.c | 231 ++++++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 194 insertions(+), 37 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 13e9bb0ce44e..0240e0a04f6a 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -67,6 +67,16 @@ struct io_mapped_ubuf { unsigned int nr_bvecs; }; +struct async_list { + spinlock_t lock; + atomic_t cnt; + struct list_head list; + + struct file *file; + off_t io_end; + size_t io_pages; +}; + struct io_ring_ctx { struct { struct percpu_ref refs; @@ -124,6 +134,8 @@ struct io_ring_ctx { struct list_head poll_list; struct list_head cancel_list; } ____cacheline_aligned_in_smp; + + struct async_list pending_async[2]; }; struct sqe_submit { @@ -155,6 +167,7 @@ struct io_kiocb { #define REQ_F_IOPOLL_COMPLETED 2 /* polled IO has completed */ #define REQ_F_IOPOLL_EAGAIN 4 /* submission got EAGAIN */ #define REQ_F_FIXED_FILE 8 /* ctx owns file */ +#define REQ_F_SEQ_PREV 16 /* sequential with previous */ u64 user_data; u64 res; @@ -198,6 +211,7 @@ static void io_ring_ctx_ref_free(struct percpu_ref *ref) static struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p) { struct io_ring_ctx *ctx; + int i; ctx = kzalloc(sizeof(*ctx), GFP_KERNEL); if (!ctx) @@ -213,6 +227,11 @@ static struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p) init_completion(&ctx->ctx_done); mutex_init(&ctx->uring_lock); init_waitqueue_head(&ctx->wait); + for (i = 0; i < ARRAY_SIZE(ctx->pending_async); i++) { + spin_lock_init(&ctx->pending_async[i].lock); + INIT_LIST_HEAD(&ctx->pending_async[i].list); + atomic_set(&ctx->pending_async[i].cnt, 0); + } spin_lock_init(&ctx->completion_lock); INIT_LIST_HEAD(&ctx->poll_list); INIT_LIST_HEAD(&ctx->cancel_list); @@ -772,6 +791,39 @@ static int io_import_iovec(struct io_ring_ctx *ctx, int rw, return import_iovec(rw, buf, sqe->len, UIO_FASTIOV, iovec, iter); } +static void io_async_list_note(int rw, struct io_kiocb *req, size_t len) +{ + struct async_list *async_list = &req->ctx->pending_async[rw]; + struct kiocb *kiocb = &req->rw; + struct file *filp = kiocb->ki_filp; + off_t io_end = kiocb->ki_pos + len; + + if (filp == async_list->file && kiocb->ki_pos == async_list->io_end) { + unsigned long max_pages; + + /* Use 8x RA size as a decent limiter for both reads/writes */ + max_pages = filp->f_ra.ra_pages; + if (!max_pages) + max_pages = VM_MAX_READAHEAD >> (PAGE_SHIFT - 10); + max_pages *= 8; + + len >>= PAGE_SHIFT; + if (async_list->io_pages + len <= max_pages) { + req->flags |= REQ_F_SEQ_PREV; + async_list->io_pages += len; + } else { + io_end = 0; + async_list->io_pages = 0; + } + } + + if (async_list->file != filp) { + async_list->io_pages = 0; + async_list->file = filp; + } + async_list->io_end = io_end; +} + static ssize_t io_read(struct io_kiocb *req, const struct io_uring_sqe *sqe, bool force_nonblock, struct io_submit_state *state) { @@ -779,6 +831,7 @@ static ssize_t io_read(struct io_kiocb *req, const struct io_uring_sqe *sqe, struct kiocb *kiocb = &req->rw; struct iov_iter iter; struct file *file; + size_t iov_count; ssize_t ret; ret = io_prep_rw(req, sqe, force_nonblock, state); @@ -797,16 +850,19 @@ static ssize_t io_read(struct io_kiocb *req, const struct io_uring_sqe *sqe, if (ret) goto out_fput; - ret = rw_verify_area(READ, file, &kiocb->ki_pos, iov_iter_count(&iter)); + iov_count = iov_iter_count(&iter); + ret = rw_verify_area(READ, file, &kiocb->ki_pos, iov_count); if (!ret) { ssize_t ret2; /* Catch -EAGAIN return for forced non-blocking submission */ ret2 = call_read_iter(file, kiocb, &iter); - if (!force_nonblock || ret2 != -EAGAIN) + if (!force_nonblock || ret2 != -EAGAIN) { io_rw_done(kiocb, ret2); - else + } else { + io_async_list_note(READ, req, iov_count); ret = -EAGAIN; + } } kfree(iovec); out_fput: @@ -822,6 +878,7 @@ static ssize_t io_write(struct io_kiocb *req, const struct io_uring_sqe *sqe, struct kiocb *kiocb = &req->rw; struct iov_iter iter; struct file *file; + size_t iov_count; ssize_t ret; ret = io_prep_rw(req, sqe, force_nonblock, state); @@ -829,10 +886,6 @@ static ssize_t io_write(struct io_kiocb *req, const struct io_uring_sqe *sqe, return ret; file = kiocb->ki_filp; - ret = -EAGAIN; - if (force_nonblock && !(kiocb->ki_flags & IOCB_DIRECT)) - goto out_fput; - ret = -EBADF; if (unlikely(!(file->f_mode & FMODE_WRITE))) goto out_fput; @@ -844,8 +897,15 @@ static ssize_t io_write(struct io_kiocb *req, const struct io_uring_sqe *sqe, if (ret) goto out_fput; - ret = rw_verify_area(WRITE, file, &kiocb->ki_pos, - iov_iter_count(&iter)); + iov_count = iov_iter_count(&iter); + + ret = -EAGAIN; + if (force_nonblock && !(kiocb->ki_flags & IOCB_DIRECT)) { + io_async_list_note(WRITE, req, iov_count); + goto out_free; + } + + ret = rw_verify_area(WRITE, file, &kiocb->ki_pos, iov_count); if (!ret) { /* * Open-code file_start_write here to grab freeze protection, @@ -863,6 +923,7 @@ static ssize_t io_write(struct io_kiocb *req, const struct io_uring_sqe *sqe, kiocb->ki_flags |= IOCB_WRITE; io_rw_done(kiocb, call_write_iter(file, kiocb, &iter)); } +out_free: kfree(iovec); out_fput: if (unlikely(ret)) @@ -1210,6 +1271,21 @@ static int __io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req, return 0; } +static struct async_list *io_async_list_from_sqe(struct io_ring_ctx *ctx, + const struct io_uring_sqe *sqe) +{ + switch (sqe->opcode) { + case IORING_OP_READV: + case IORING_OP_READ_FIXED: + return &ctx->pending_async[READ]; + case IORING_OP_WRITEV: + case IORING_OP_WRITE_FIXED: + return &ctx->pending_async[WRITE]; + default: + return NULL; + } +} + static inline bool io_sqe_needs_user(const struct io_uring_sqe *sqe) { return !(sqe->opcode == IORING_OP_READ_FIXED || @@ -1219,50 +1295,124 @@ static inline bool io_sqe_needs_user(const struct io_uring_sqe *sqe) static void io_sq_wq_submit_work(struct work_struct *work) { struct io_kiocb *req = container_of(work, struct io_kiocb, work); - struct sqe_submit *s = &req->submit; - u64 user_data = s->sqe->user_data; struct io_ring_ctx *ctx = req->ctx; + struct mm_struct *cur_mm = NULL; struct files_struct *old_files; + struct async_list *async_list; + LIST_HEAD(req_list); mm_segment_t old_fs; - bool needs_user; int ret; - /* Ensure we clear previously set forced non-block flag */ - req->flags &= ~REQ_F_FORCE_NONBLOCK; - old_files = current->files; current->files = ctx->sqo_files; + async_list = io_async_list_from_sqe(ctx, req->submit.sqe); +restart: + do { + struct sqe_submit *s = &req->submit; + u64 user_data = s->sqe->user_data; + + /* Ensure we clear previously set forced non-block flag */ + req->flags &= ~REQ_F_FORCE_NONBLOCK; + + ret = 0; + if (io_sqe_needs_user(s->sqe) && !cur_mm) { + if (!mmget_not_zero(ctx->sqo_mm)) { + ret = -EFAULT; + } else { + cur_mm = ctx->sqo_mm;; + use_mm(ctx->sqo_mm); + old_fs = get_fs(); + set_fs(USER_DS); + } + } + + if (!ret) + ret = __io_submit_sqe(ctx, req, s, false, NULL); + if (ret) { + io_cqring_add_event(ctx, user_data, ret, 0); + io_free_req(req); + } + if (!async_list) + break; + if (!list_empty(&req_list)) { + req = list_first_entry(&req_list, struct io_kiocb, + list); + list_del(&req->list); + continue; + } + if (list_empty(&async_list->list)) + break; + + req = NULL; + spin_lock(&async_list->lock); + if (list_empty(&async_list->list)) { + spin_unlock(&async_list->lock); + break; + } + list_splice_init(&async_list->list, &req_list); + spin_unlock(&async_list->lock); + + req = list_first_entry(&req_list, struct io_kiocb, list); + list_del(&req->list); + } while (req); + /* - * If we're doing IO to fixed buffers, we don't need to get/set - * user context + * Rare case of racing with a submitter. If we find the count has + * dropped to zero AND we have pending work items, then restart + * the processing. This is a tiny race window. */ - needs_user = io_sqe_needs_user(s->sqe); - if (needs_user) { - if (!mmget_not_zero(ctx->sqo_mm)) { - ret = -EFAULT; - goto err; + ret = atomic_dec_return(&async_list->cnt); + while (!ret && !list_empty(&async_list->list)) { + spin_lock(&async_list->lock); + atomic_inc(&async_list->cnt); + list_splice_init(&async_list->list, &req_list); + spin_unlock(&async_list->lock); + + if (!list_empty(&req_list)) { + req = list_first_entry(&req_list, struct io_kiocb, + list); + list_del(&req->list); + goto restart; } - use_mm(ctx->sqo_mm); - old_fs = get_fs(); - set_fs(USER_DS); + ret = atomic_dec_return(&async_list->cnt); } - ret = __io_submit_sqe(ctx, req, s, false, NULL); - - if (needs_user) { + if (cur_mm) { set_fs(old_fs); - unuse_mm(ctx->sqo_mm); - mmput(ctx->sqo_mm); - } -err: - if (ret) { - io_cqring_add_event(ctx, user_data, ret, 0); - io_free_req(req); + unuse_mm(cur_mm); + mmput(cur_mm); } current->files = old_files; } +/* + * See if we can piggy back onto previously submitted work, that is still + * running. We currently only allow this if the new request is sequential + * to the previous one we punted. + */ +static bool io_add_to_prev_work(struct async_list *list, struct io_kiocb *req) +{ + bool ret = false; + + if (!list) + return false; + if (!(req->flags & REQ_F_SEQ_PREV)) + return false; + if (!atomic_read(&list->cnt)) + return false; + + ret = true; + spin_lock(&list->lock); + list_add_tail(&req->list, &list->list); + if (!atomic_read(&list->cnt)) { + list_del_init(&req->list); + ret = false; + } + spin_unlock(&list->lock); + return ret; +} + static int io_submit_sqe(struct io_ring_ctx *ctx, struct sqe_submit *s, struct io_submit_state *state) { @@ -1279,9 +1429,16 @@ static int io_submit_sqe(struct io_ring_ctx *ctx, struct sqe_submit *s, ret = __io_submit_sqe(ctx, req, s, true, state); if (ret == -EAGAIN) { + struct async_list *list; + + list = io_async_list_from_sqe(ctx, s->sqe); memcpy(&req->submit, s, sizeof(*s)); - INIT_WORK(&req->work, io_sq_wq_submit_work); - queue_work(ctx->sqo_wq, &req->work); + if (!io_add_to_prev_work(list, req)) { + if (list) + atomic_inc(&list->cnt); + INIT_WORK(&req->work, io_sq_wq_submit_work); + queue_work(ctx->sqo_wq, &req->work); + } ret = 0; } if (ret) From patchwork Mon Jan 28 21:35:38 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Axboe X-Patchwork-Id: 10784889 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 6829C1390 for ; Mon, 28 Jan 2019 21:36:19 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 51C932B51A for ; Mon, 28 Jan 2019 21:36:19 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 45D822B552; Mon, 28 Jan 2019 21:36:19 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id E59282B51A for ; 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Mon, 28 Jan 2019 13:36:16 -0800 (PST) From: Jens Axboe To: linux-aio@kvack.org, linux-block@vger.kernel.org, linux-man@vger.kernel.org, linux-api@vger.kernel.org Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, Jens Axboe Subject: [PATCH 18/18] io_uring: add io_uring_event cache hit information Date: Mon, 28 Jan 2019 14:35:38 -0700 Message-Id: <20190128213538.13486-19-axboe@kernel.dk> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190128213538.13486-1-axboe@kernel.dk> References: <20190128213538.13486-1-axboe@kernel.dk> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Add hint on whether a read was served out of the page cache, or if it hit media. This is useful for buffered async IO, O_DIRECT reads would never have this set (for obvious reasons). If the read hit page cache, cqe->flags will have IOCQE_FLAG_CACHEHIT set. Signed-off-by: Jens Axboe --- fs/io_uring.c | 7 ++++++- include/uapi/linux/io_uring.h | 5 +++++ 2 files changed, 11 insertions(+), 1 deletion(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 0240e0a04f6a..9b4b4f9d06a5 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -558,11 +558,16 @@ static void io_fput(struct io_kiocb *req) static void io_complete_rw(struct kiocb *kiocb, long res, long res2) { struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw); + unsigned ev_flags = 0; kiocb_end_write(kiocb); io_fput(req); - io_cqring_add_event(req->ctx, req->user_data, res, 0); + + if (res > 0 && (req->flags & REQ_F_FORCE_NONBLOCK)) + ev_flags = IOCQE_FLAG_CACHEHIT; + + io_cqring_add_event(req->ctx, req->user_data, res, ev_flags); io_free_req(req); } diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h index 39d3d3336dce..589b6402081d 100644 --- a/include/uapi/linux/io_uring.h +++ b/include/uapi/linux/io_uring.h @@ -71,6 +71,11 @@ struct io_uring_cqe { __u32 flags; }; +/* + * io_uring_event->flags + */ +#define IOCQE_FLAG_CACHEHIT (1 << 0) /* IO did not hit media */ + /* * Magic offsets for the application to mmap the data it needs */