From mboxrd@z Thu Jan 1 00:00:00 1970 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 A47BEC00528 for ; Thu, 20 Jul 2023 18:13:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231314AbjGTSN2 (ORCPT ); Thu, 20 Jul 2023 14:13:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53134 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231301AbjGTSN1 (ORCPT ); Thu, 20 Jul 2023 14:13:27 -0400 Received: from mail-io1-xd2f.google.com (mail-io1-xd2f.google.com [IPv6:2607:f8b0:4864:20::d2f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6364A270B for ; Thu, 20 Jul 2023 11:13:26 -0700 (PDT) Received: by mail-io1-xd2f.google.com with SMTP id ca18e2360f4ac-760dff4b701so13424939f.0 for ; Thu, 20 Jul 2023 11:13:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20221208.gappssmtp.com; s=20221208; t=1689876805; x=1690481605; 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=uXqZdaZ6Mquv4fIr1Ve7JSk8CcFji/eSZ6SaOz1unh0=; b=gkBbhoaJhW9QE7tFd5BKEysDmJS6oIW0zakPz2TmWExyM5h0e0/zYspxWItXES0B2c AmUMz1xk4bpSXgZVRJDz2L59lYjvt+2CPyXqTha5Tn7xc3FAUTHNRP/9Uu3ELEcHGUek mbbJ7WZ2ryoaRSW1t37jYZfYAYw98N8W2M8lS05npoJjj3QTOnCHIdx5tTwqHlfaVWoG 4bsgA5MEtBPU75KQdCvK1lFVtqrIkRIu6bSeVgnEUAN7Dj8kp4scq7G8nxRL27W67QBL ZXPin3bk6sqG7COAkitQ+WWXoUIZyHPvJal/OYtfGyLm2JLIZ1sYkkrE5mjoQJxLK1FY Lj7w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1689876805; x=1690481605; 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=uXqZdaZ6Mquv4fIr1Ve7JSk8CcFji/eSZ6SaOz1unh0=; b=Ozmg9cu18MKdFJqIr4syBYxmCoVEK2+ebMprJFUFxXzguHb6MJHd56ph7xj3yt820z rbyEDS6pKo27On/SG5acHtsAEdW4Ey+y3V6vC5o/8NtWrjNuInnltLAHdX1OMerjKT6z ca3ctACCZ1Te5vcCJkXGJhtGRD36yAI2jlGymOch/qvGsZ7LqT+Wgym2yq0a3qcBxN/0 AqkAITFU1n8F3H3LKTmNZqUlEGckjtCVI5DhSXdtHRxrrCysz6aDWat/PptKo1qPQH3C hZPODGzOXwfJOI355oFxXTaOESxv8Slai22kRP3ujBm1j5x6GALi9UeMkCYoFmuPD/Dj 7REQ== X-Gm-Message-State: ABy/qLZK21wYX46SlW74xwRJPkInBGQo7A3yIGmf63Khk+WB5XqtLEen r+lGJatiVrAeZ2YJo+v6l7kpwYVLs2z+Ny5efW4= X-Google-Smtp-Source: APBJJlH7ibxVZcFGYESD3kYWTxfRRHxo2GQ6mcaCElNBn5D+3k2OZwRxH4WCvaIa00ZBvqqERnpfcw== X-Received: by 2002:a92:dacf:0:b0:345:db9a:be2c with SMTP id o15-20020a92dacf000000b00345db9abe2cmr3262388ilq.1.1689876805117; Thu, 20 Jul 2023 11:13:25 -0700 (PDT) Received: from localhost.localdomain ([96.43.243.2]) by smtp.gmail.com with ESMTPSA id v6-20020a92c6c6000000b003457e1daba8sm419171ilm.8.2023.07.20.11.13.23 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 20 Jul 2023 11:13:24 -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 8/8] iomap: support IOCB_DIO_DEFER Date: Thu, 20 Jul 2023 12:13:10 -0600 Message-Id: <20230720181310.71589-9-axboe@kernel.dk> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230720181310.71589-1-axboe@kernel.dk> References: <20230720181310.71589-1-axboe@kernel.dk> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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 | 54 +++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 53 insertions(+), 1 deletion(-) diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c index cce9af019705..de86680968a4 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_STABLE_WRITE (1 << 28) #define IOMAP_DIO_NEED_SYNC (1 << 29) @@ -132,6 +133,11 @@ 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); @@ -192,6 +198,31 @@ 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 @@ -288,12 +319,17 @@ static loff_t iomap_dio_bio_iter(const struct iomap_iter *iter, * after IO completion such as unwritten extent conversion) and * the underlying device either supports FUA or doesn't have * a volatile write cache. This allows us to avoid cache flushes - * on IO completion. + * on IO completion. If we can't use stable writes and need to + * sync, disable in-task completions as dio completion will + * need to call generic_write_sync() which will do a blocking + * fsync / cache flush call. */ if (!(iomap->flags & (IOMAP_F_SHARED|IOMAP_F_DIRTY)) && (dio->flags & IOMAP_DIO_STABLE_WRITE) && (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; } /* @@ -319,6 +355,13 @@ 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); + + /* + * If need_zeroout is set, then this is a new or unwritten + * extent. These need extra handling at completion time, so + * disable in-task deferred completion for those. + */ + dio->flags &= ~IOMAP_DIO_DEFER_COMP; } /* @@ -557,6 +600,15 @@ __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 || -- 2.40.1