From patchwork Wed Jul 19 19:54:17 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Axboe X-Patchwork-Id: 13319441 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id F35CCC001B0 for ; Wed, 19 Jul 2023 19:54:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231304AbjGSTyg (ORCPT ); Wed, 19 Jul 2023 15:54:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41534 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231316AbjGSTyd (ORCPT ); Wed, 19 Jul 2023 15:54:33 -0400 Received: from mail-io1-xd33.google.com (mail-io1-xd33.google.com [IPv6:2607:f8b0:4864:20::d33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 38F5F1FD3 for ; Wed, 19 Jul 2023 12:54:32 -0700 (PDT) Received: by mail-io1-xd33.google.com with SMTP id ca18e2360f4ac-785d3a53ed6so82448739f.1 for ; Wed, 19 Jul 2023 12:54:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20221208.gappssmtp.com; s=20221208; t=1689796471; x=1690401271; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=kTvYQlDOhP6EOVmXA2umB2ZKrh0BWM6v9ydQBvMCtEo=; b=bntvLtM93TfxHDv1res/Le2NnqIAI2hPK1vOgQO+ZboYSOMGk0AyDqi0tcI2iSWnP2 kBPZ2hoO6+JtUocaEoPTyx+AnaVilw9JCpUvrbfOISFu8KlGjVmsTul36huDeAfZFZom famDHX0bTR7bVniAyiKg1W1WvspZAHb9qmUv5yZ40X+abb0PeHmq7e/9tRRPBZwXJzSF LX/bCOiBKfF7z0Og5QDpXU5O+x4rltwbjzmkW9YYP0nZISYPG2ZRZQWdKEDHgHFwV8lA cITkp69rHLOflHD7M2nh/eraJ8QIJhB9FK8g6SRJ2PIyDH4CPvm+UjZbjZi0UCHoDGfE yhKw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1689796471; x=1690401271; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=kTvYQlDOhP6EOVmXA2umB2ZKrh0BWM6v9ydQBvMCtEo=; b=LABpYxXAXzh0sIMm30O47Znj2vIb+w10bBwnS+dx7Gc+k+cZii1zRmygqO6LgYbaNE 62ky7rHJLs52krVl2mF6zRB9/ABUlm/deJ57coVO9ilHf7rEtQhGkZvGbG6Bi2/899/9 nnI0iOWf+VMYZdgmchHwUyVqeQTBacCGDmPNBZH2F1TGn4/L4EdT8nFObJ//be6igYEk xs+AkJa2nDuI6xG+Zburdl7GiIwC+JS22FF3ru4315+wX5ARKu2CVALcKgKF8HYXRNN0 KtN8gRb9BZIMH77f93PAKSQ3plKObXj+Nbbu9PSN5gqZWFlgNWiCK8CNvzoPcNfCPtoh HA2A== X-Gm-Message-State: ABy/qLYbURSeTAiyMEEjp8LnzNuLXacRQnNDVc8YFeeyW4sEmbhY/0Dt CPNH/vCKu4TF6tIyvyyZIfAjLV3Z7AW4xP/clh0= X-Google-Smtp-Source: APBJJlFnEcVMxJ5LOd6PR/a75IhjhuRWzWbS5J5uUVT/bik2+nthisdHTN19bYSQbo/z7VRMMUf64Q== X-Received: by 2002:a05:6602:3423:b0:780:d65c:d78f with SMTP id n35-20020a056602342300b00780d65cd78fmr586047ioz.2.1689796471049; Wed, 19 Jul 2023 12:54:31 -0700 (PDT) Received: from localhost.localdomain ([96.43.243.2]) by smtp.gmail.com with ESMTPSA id j21-20020a02a695000000b0042bb13cb80fsm1471893jam.120.2023.07.19.12.54.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 19 Jul 2023 12:54:30 -0700 (PDT) From: Jens Axboe To: io-uring@vger.kernel.org, linux-xfs@vger.kernel.org Cc: hch@lst.de, andres@anarazel.de, david@fromorbit.com, Jens Axboe Subject: [PATCH 6/6] iomap: support IOCB_DIO_DEFER Date: Wed, 19 Jul 2023 13:54:17 -0600 Message-Id: <20230719195417.1704513-7-axboe@kernel.dk> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230719195417.1704513-1-axboe@kernel.dk> References: <20230719195417.1704513-1-axboe@kernel.dk> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org If IOCB_DIO_DEFER is set, utilize that to set kiocb->dio_complete handler and data for that callback. Rather than punt the completion to a workqueue, we pass back the handler and data to the issuer and will get a callback from a safe task context. Using the following fio job to randomly dio write 4k blocks at queue depths of 1..16: fio --name=dio-write --filename=/data1/file --time_based=1 \ --runtime=10 --bs=4096 --rw=randwrite --norandommap --buffered=0 \ --cpus_allowed=4 --ioengine=io_uring --iodepth=$depth shows the following results before and after this patch: Stock Patched Diff ======================================= QD1 155K 162K + 4.5% QD2 290K 313K + 7.9% QD4 533K 597K +12.0% QD8 604K 827K +36.9% QD16 615K 845K +37.4% which shows nice wins all around. If we factored in per-IOP efficiency, the wins look even nicer. This becomes apparent as queue depth rises, as the offloaded workqueue completions runs out of steam. Signed-off-by: Jens Axboe --- fs/iomap/direct-io.c | 47 +++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 46 insertions(+), 1 deletion(-) diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c index b30c3edf2ef3..b7055d50dd99 100644 --- a/fs/iomap/direct-io.c +++ b/fs/iomap/direct-io.c @@ -20,6 +20,7 @@ * Private flags for iomap_dio, must not overlap with the public ones in * iomap.h: */ +#define IOMAP_DIO_DEFER_COMP (1 << 26) #define IOMAP_DIO_INLINE_COMP (1 << 27) #define IOMAP_DIO_WRITE_FUA (1 << 28) #define IOMAP_DIO_NEED_SYNC (1 << 29) @@ -131,6 +132,11 @@ ssize_t iomap_dio_complete(struct iomap_dio *dio) } EXPORT_SYMBOL_GPL(iomap_dio_complete); +static ssize_t iomap_dio_deferred_complete(void *data) +{ + return iomap_dio_complete(data); +} + static void iomap_dio_complete_work(struct work_struct *work) { struct iomap_dio *dio = container_of(work, struct iomap_dio, aio.work); @@ -180,6 +186,31 @@ void iomap_dio_bio_end_io(struct bio *bio) goto release_bio; } + /* + * If this dio is flagged with IOMAP_DIO_DEFER_COMP, then schedule + * our completion that way to avoid an async punt to a workqueue. + */ + if (dio->flags & IOMAP_DIO_DEFER_COMP) { + /* only polled IO cares about private cleared */ + iocb->private = dio; + iocb->dio_complete = iomap_dio_deferred_complete; + + /* + * Invoke ->ki_complete() directly. We've assigned out + * dio_complete callback handler, and since the issuer set + * IOCB_DIO_DEFER, we know their ki_complete handler will + * notice ->dio_complete being set and will defer calling that + * handler until it can be done from a safe task context. + * + * Note that the 'res' being passed in here is not important + * for this case. The actual completion value of the request + * will be gotten from dio_complete when that is run by the + * issuer. + */ + iocb->ki_complete(iocb, 0); + goto release_bio; + } + /* * Async DIO completion that requires filesystem level completion work * gets punted to a work queue to complete as the operation may require @@ -277,12 +308,15 @@ static loff_t iomap_dio_bio_iter(const struct iomap_iter *iter, * data IO that doesn't require any metadata updates (including * after IO completion such as unwritten extent conversion) and * the underlying device supports FUA. This allows us to avoid - * cache flushes on IO completion. + * cache flushes on IO completion. If we can't use FUA and + * need to sync, disable in-task completions. */ if (!(iomap->flags & (IOMAP_F_SHARED|IOMAP_F_DIRTY)) && (dio->flags & IOMAP_DIO_WRITE_FUA) && (bdev_fua(iomap->bdev) || !bdev_write_cache(iomap->bdev))) use_fua = true; + else if (dio->flags & IOMAP_DIO_NEED_SYNC) + dio->flags &= ~IOMAP_DIO_DEFER_COMP; } /* @@ -308,6 +342,8 @@ static loff_t iomap_dio_bio_iter(const struct iomap_iter *iter, pad = pos & (fs_block_size - 1); if (pad) iomap_dio_zero(iter, dio, pos - pad, pad); + + dio->flags &= ~IOMAP_DIO_DEFER_COMP; } /* @@ -547,6 +583,15 @@ __iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, iomi.flags |= IOMAP_WRITE; dio->flags |= IOMAP_DIO_WRITE; + /* + * Flag as supporting deferred completions, if the issuer + * groks it. This can avoid a workqueue punt for writes. + * We may later clear this flag if we need to do other IO + * as part of this IO completion. + */ + if (iocb->ki_flags & IOCB_DIO_DEFER) + dio->flags |= IOMAP_DIO_DEFER_COMP; + if (dio_flags & IOMAP_DIO_OVERWRITE_ONLY) { ret = -EAGAIN; if (iomi.pos >= dio->i_size ||