From patchwork Tue May 30 18:09:58 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Hajnoczi X-Patchwork-Id: 13260871 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id A63C9C7EE23 for ; Tue, 30 May 2023 18:11:42 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1q43oS-0007uv-QD; Tue, 30 May 2023 14:11:16 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1q43oR-0007m8-6G for qemu-devel@nongnu.org; Tue, 30 May 2023 14:11:15 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1q43oJ-0005Mm-8d for qemu-devel@nongnu.org; Tue, 30 May 2023 14:11:14 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1685470266; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=XV97eP38CRr/0Son/iV5qHHD0cfAwlv15JJUdp2ioGU=; b=G8Il/GZtq/Rn1GwMSWJkdC6Ewz3Z0mioeffre17jSPEZe1gxoriCmJaFDNyQmJcIqMBH/2 lC2zBILtG2y8sEcTNG4MVTdTNcoGGLbeh+bIGx0z+1bmleTIVS7fMkx6YFObjLd8WdUAQI Z5sdJu1rcmR9fwMPcxy3MxFbQr3H7Do= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-141-uIvKrrFFNuyGlrGvyulc_w-1; Tue, 30 May 2023 14:11:03 -0400 X-MC-Unique: uIvKrrFFNuyGlrGvyulc_w-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id B1D3F8030D5; Tue, 30 May 2023 18:11:02 +0000 (UTC) Received: from localhost (unknown [10.39.192.97]) by smtp.corp.redhat.com (Postfix) with ESMTP id 5D95620296C6; Tue, 30 May 2023 18:10:36 +0000 (UTC) From: Stefan Hajnoczi To: qemu-devel@nongnu.org Cc: Paolo Bonzini , eblake@redhat.com, Hanna Reitz , Fam Zheng , sgarzare@redhat.com, qemu-block@nongnu.org, xen-devel@lists.xenproject.org, Julia Suvorova , Stefano Stabellini , =?utf-8?q?Philippe_Mathieu-Dau?= =?utf-8?q?d=C3=A9?= , Paul Durrant , Kevin Wolf , Anthony Perard , "Michael S. Tsirkin" , Stefan Hajnoczi , Aarushi Mehta Subject: [PATCH v3 5/6] block/linux-aio: convert to blk_io_plug_call() API Date: Tue, 30 May 2023 14:09:58 -0400 Message-Id: <20230530180959.1108766-6-stefanha@redhat.com> In-Reply-To: <20230530180959.1108766-1-stefanha@redhat.com> References: <20230530180959.1108766-1-stefanha@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.4 Received-SPF: pass client-ip=170.10.129.124; envelope-from=stefanha@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -16 X-Spam_score: -1.7 X-Spam_bar: - X-Spam_report: (-1.7 / 5.0 requ) BAYES_00=-1.9, DKIM_INVALID=0.1, DKIM_SIGNED=0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Stop using the .bdrv_co_io_plug() API because it is not multi-queue block layer friendly. Use the new blk_io_plug_call() API to batch I/O submission instead. Note that a dev_max_batch check is dropped in laio_io_unplug() because the semantics of unplug_fn() are different from .bdrv_co_unplug(): 1. unplug_fn() is only called when the last blk_io_unplug() call occurs, not every time blk_io_unplug() is called. 2. unplug_fn() is per-thread, not per-BlockDriverState, so there is no way to get per-BlockDriverState fields like dev_max_batch. Therefore this condition cannot be moved to laio_unplug_fn(). It is not obvious that this condition affects performance in practice, so I am removing it instead of trying to come up with a more complex mechanism to preserve the condition. Signed-off-by: Stefan Hajnoczi Reviewed-by: Eric Blake Reviewed-by: Stefano Garzarella --- include/block/raw-aio.h | 7 ------- block/file-posix.c | 28 ---------------------------- block/linux-aio.c | 41 +++++++++++------------------------------ 3 files changed, 11 insertions(+), 65 deletions(-) diff --git a/include/block/raw-aio.h b/include/block/raw-aio.h index da60ca13ef..0f63c2800c 100644 --- a/include/block/raw-aio.h +++ b/include/block/raw-aio.h @@ -62,13 +62,6 @@ int coroutine_fn laio_co_submit(int fd, uint64_t offset, QEMUIOVector *qiov, void laio_detach_aio_context(LinuxAioState *s, AioContext *old_context); void laio_attach_aio_context(LinuxAioState *s, AioContext *new_context); - -/* - * laio_io_plug/unplug work in the thread's current AioContext, therefore the - * caller must ensure that they are paired in the same IOThread. - */ -void laio_io_plug(void); -void laio_io_unplug(uint64_t dev_max_batch); #endif /* io_uring.c - Linux io_uring implementation */ #ifdef CONFIG_LINUX_IO_URING diff --git a/block/file-posix.c b/block/file-posix.c index 7baa8491dd..ac1ed54811 100644 --- a/block/file-posix.c +++ b/block/file-posix.c @@ -2550,26 +2550,6 @@ static int coroutine_fn raw_co_pwritev(BlockDriverState *bs, int64_t offset, return raw_co_prw(bs, offset, bytes, qiov, QEMU_AIO_WRITE); } -static void coroutine_fn raw_co_io_plug(BlockDriverState *bs) -{ - BDRVRawState __attribute__((unused)) *s = bs->opaque; -#ifdef CONFIG_LINUX_AIO - if (s->use_linux_aio) { - laio_io_plug(); - } -#endif -} - -static void coroutine_fn raw_co_io_unplug(BlockDriverState *bs) -{ - BDRVRawState __attribute__((unused)) *s = bs->opaque; -#ifdef CONFIG_LINUX_AIO - if (s->use_linux_aio) { - laio_io_unplug(s->aio_max_batch); - } -#endif -} - static int coroutine_fn raw_co_flush_to_disk(BlockDriverState *bs) { BDRVRawState *s = bs->opaque; @@ -3914,8 +3894,6 @@ BlockDriver bdrv_file = { .bdrv_co_copy_range_from = raw_co_copy_range_from, .bdrv_co_copy_range_to = raw_co_copy_range_to, .bdrv_refresh_limits = raw_refresh_limits, - .bdrv_co_io_plug = raw_co_io_plug, - .bdrv_co_io_unplug = raw_co_io_unplug, .bdrv_attach_aio_context = raw_aio_attach_aio_context, .bdrv_co_truncate = raw_co_truncate, @@ -4286,8 +4264,6 @@ static BlockDriver bdrv_host_device = { .bdrv_co_copy_range_from = raw_co_copy_range_from, .bdrv_co_copy_range_to = raw_co_copy_range_to, .bdrv_refresh_limits = raw_refresh_limits, - .bdrv_co_io_plug = raw_co_io_plug, - .bdrv_co_io_unplug = raw_co_io_unplug, .bdrv_attach_aio_context = raw_aio_attach_aio_context, .bdrv_co_truncate = raw_co_truncate, @@ -4424,8 +4400,6 @@ static BlockDriver bdrv_host_cdrom = { .bdrv_co_pwritev = raw_co_pwritev, .bdrv_co_flush_to_disk = raw_co_flush_to_disk, .bdrv_refresh_limits = cdrom_refresh_limits, - .bdrv_co_io_plug = raw_co_io_plug, - .bdrv_co_io_unplug = raw_co_io_unplug, .bdrv_attach_aio_context = raw_aio_attach_aio_context, .bdrv_co_truncate = raw_co_truncate, @@ -4552,8 +4526,6 @@ static BlockDriver bdrv_host_cdrom = { .bdrv_co_pwritev = raw_co_pwritev, .bdrv_co_flush_to_disk = raw_co_flush_to_disk, .bdrv_refresh_limits = cdrom_refresh_limits, - .bdrv_co_io_plug = raw_co_io_plug, - .bdrv_co_io_unplug = raw_co_io_unplug, .bdrv_attach_aio_context = raw_aio_attach_aio_context, .bdrv_co_truncate = raw_co_truncate, diff --git a/block/linux-aio.c b/block/linux-aio.c index 442c86209b..5021aed68f 100644 --- a/block/linux-aio.c +++ b/block/linux-aio.c @@ -15,6 +15,7 @@ #include "qemu/event_notifier.h" #include "qemu/coroutine.h" #include "qapi/error.h" +#include "sysemu/block-backend.h" /* Only used for assertions. */ #include "qemu/coroutine_int.h" @@ -46,7 +47,6 @@ struct qemu_laiocb { }; typedef struct { - int plugged; unsigned int in_queue; unsigned int in_flight; bool blocked; @@ -236,7 +236,7 @@ static void qemu_laio_process_completions_and_submit(LinuxAioState *s) { qemu_laio_process_completions(s); - if (!s->io_q.plugged && !QSIMPLEQ_EMPTY(&s->io_q.pending)) { + if (!QSIMPLEQ_EMPTY(&s->io_q.pending)) { ioq_submit(s); } } @@ -277,7 +277,6 @@ static void qemu_laio_poll_ready(EventNotifier *opaque) static void ioq_init(LaioQueue *io_q) { QSIMPLEQ_INIT(&io_q->pending); - io_q->plugged = 0; io_q->in_queue = 0; io_q->in_flight = 0; io_q->blocked = false; @@ -354,31 +353,11 @@ static uint64_t laio_max_batch(LinuxAioState *s, uint64_t dev_max_batch) return max_batch; } -void laio_io_plug(void) +static void laio_unplug_fn(void *opaque) { - AioContext *ctx = qemu_get_current_aio_context(); - LinuxAioState *s = aio_get_linux_aio(ctx); + LinuxAioState *s = opaque; - s->io_q.plugged++; -} - -void laio_io_unplug(uint64_t dev_max_batch) -{ - AioContext *ctx = qemu_get_current_aio_context(); - LinuxAioState *s = aio_get_linux_aio(ctx); - - assert(s->io_q.plugged); - s->io_q.plugged--; - - /* - * Why max batch checking is performed here: - * Another BDS may have queued requests with a higher dev_max_batch and - * therefore in_queue could now exceed our dev_max_batch. Re-check the max - * batch so we can honor our device's dev_max_batch. - */ - if (s->io_q.in_queue >= laio_max_batch(s, dev_max_batch) || - (!s->io_q.plugged && - !s->io_q.blocked && !QSIMPLEQ_EMPTY(&s->io_q.pending))) { + if (!s->io_q.blocked && !QSIMPLEQ_EMPTY(&s->io_q.pending)) { ioq_submit(s); } } @@ -410,10 +389,12 @@ static int laio_do_submit(int fd, struct qemu_laiocb *laiocb, off_t offset, QSIMPLEQ_INSERT_TAIL(&s->io_q.pending, laiocb, next); s->io_q.in_queue++; - if (!s->io_q.blocked && - (!s->io_q.plugged || - s->io_q.in_queue >= laio_max_batch(s, dev_max_batch))) { - ioq_submit(s); + if (!s->io_q.blocked) { + if (s->io_q.in_queue >= laio_max_batch(s, dev_max_batch)) { + ioq_submit(s); + } else { + blk_io_plug_call(laio_unplug_fn, s); + } } return 0;