From patchwork Wed Apr 17 16:51:38 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mikulas Patocka X-Patchwork-Id: 13633627 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5FC8C16FF38 for ; Wed, 17 Apr 2024 16:52:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713372768; cv=none; b=EyJsus2eHiUuB+jg774ZjaAGk3LiOemjdhonJcY7sYB6WvIEhJtVZ1wGpi7jWBiMeMRLGrbkT+3KVEdqDCXRe5OYHznSI0kmNw84d+8J72kXalPXLC8jZGypEzVKgYbOD2pMK1p7Jew/lkWYk2MYvRvjLwmipbR7ysDxM+R7kKw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713372768; c=relaxed/simple; bh=B2fMwR3FShAzjynlmBht9WceiKyd0W2VOuCtbPlpPiQ=; h=Date:From:To:cc:Subject:Message-ID:MIME-Version:Content-Type; b=KgT0Zruyg71a3uc8jvJ0Nl+APlr64fqsCpAVJHI2UnjHs59Eon3XVc150q7yB4T1OnnjbTHbRrZsPn3WUhy/bWc/s3DABtoQklbuaHyh3dDhOtcFv2wlzpEQG662JaKCmGPWhcEhL45ap3PsidK+RGMK2NuYFRDx3EcPs5yuMR4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=SUGv+PvK; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="SUGv+PvK" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1713372765; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type; bh=SjplzZoluTIe1o36u1uDOUnzCJidPg6EwC9CMT0pgh8=; b=SUGv+PvKHNUZUSdVnOPwA7IilH3Ox0SLd43is3NMUzks81XwiuDZM6M6E/ANRAoMNPAVp1 ZKcvrQHwM8FtNz/lx5rZySAfEto2/GyD6yiu7r+3gOCAw557nCh+fuaudMeL48qOqNk3QQ KZdaljg5WGSR3pI7u6e3uY5wZalC/IE= Received: from mimecast-mx02.redhat.com (66.187.233.88 [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-173-9WehWUvfMnCmwsDXpk2nxQ-1; Wed, 17 Apr 2024 12:51:40 -0400 X-MC-Unique: 9WehWUvfMnCmwsDXpk2nxQ-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 3C89A834FB3; Wed, 17 Apr 2024 16:51:39 +0000 (UTC) Received: from file1-rdu.file-001.prod.rdu2.dc.redhat.com (unknown [10.11.5.21]) by smtp.corp.redhat.com (Postfix) with ESMTPS id E59EC1C0F133; Wed, 17 Apr 2024 16:51:38 +0000 (UTC) Received: by file1-rdu.file-001.prod.rdu2.dc.redhat.com (Postfix, from userid 12668) id D051330BFED5; Wed, 17 Apr 2024 16:51:38 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by file1-rdu.file-001.prod.rdu2.dc.redhat.com (Postfix) with ESMTP id CF4973FB54; Wed, 17 Apr 2024 18:51:38 +0200 (CEST) Date: Wed, 17 Apr 2024 18:51:38 +0200 (CEST) From: Mikulas Patocka To: Mike Snitzer , Damien Le Moal , Jens Axboe , Peter Zijlstra , Ingo Molnar , Will Deacon , Waiman Long cc: Guangwu Zhang , dm-devel@lists.linux.dev, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v4] dm-io: don't warn if flush takes too long time Message-ID: <65c83995-1db-87ff-17df-20c43c1b74d7@redhat.com> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.7 There was reported hang warning when using dm-integrity on the top of loop device on XFS on a rotational disk. The warning was triggered because flush on the loop device was too slow. There's no easy way to reduce the latency, so I made a patch that shuts the warning up. There's already a function blk_wait_io that avoids the hung task warning. This commit moves this function from block/blk.h to kernel/sched/completion.c, renames it to wait_for_completion_long_io (because it is not dependent on the block layer at all) and uses it in dm-io instead of wait_for_completion_io. [ 1352.586981] INFO: task kworker/1:2:14820 blocked for more than 120 seconds. [ 1352.593951] Not tainted 4.18.0-552.el8_10.x86_64 #1 [ 1352.599358] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 1352.607202] Call Trace: [ 1352.609670] __schedule+0x2d1/0x870 [ 1352.613173] ? update_load_avg+0x7e/0x710 [ 1352.617193] ? update_load_avg+0x7e/0x710 [ 1352.621214] schedule+0x55/0xf0 [ 1352.624371] schedule_timeout+0x281/0x320 [ 1352.628393] ? __schedule+0x2d9/0x870 [ 1352.632065] io_schedule_timeout+0x19/0x40 [ 1352.636176] wait_for_completion_io+0x96/0x100 [ 1352.640639] sync_io+0xcc/0x120 [dm_mod] [ 1352.644592] dm_io+0x209/0x230 [dm_mod] [ 1352.648436] ? bit_wait_timeout+0xa0/0xa0 [ 1352.652461] ? vm_next_page+0x20/0x20 [dm_mod] [ 1352.656924] ? km_get_page+0x60/0x60 [dm_mod] [ 1352.661298] dm_bufio_issue_flush+0xa0/0xd0 [dm_bufio] [ 1352.666448] dm_bufio_write_dirty_buffers+0x1a0/0x1e0 [dm_bufio] [ 1352.672462] dm_integrity_flush_buffers+0x32/0x140 [dm_integrity] [ 1352.678567] ? lock_timer_base+0x67/0x90 [ 1352.682505] ? __timer_delete.part.36+0x5c/0x90 [ 1352.687050] integrity_commit+0x31a/0x330 [dm_integrity] [ 1352.692368] ? __switch_to+0x10c/0x430 [ 1352.696131] process_one_work+0x1d3/0x390 [ 1352.700152] ? process_one_work+0x390/0x390 [ 1352.704348] worker_thread+0x30/0x390 [ 1352.708019] ? process_one_work+0x390/0x390 [ 1352.712214] kthread+0x134/0x150 [ 1352.715459] ? set_kthread_struct+0x50/0x50 [ 1352.719659] ret_from_fork+0x1f/0x40 Signed-off-by: Mikulas Patocka --- block/bio.c | 2 +- block/blk-mq.c | 2 +- block/blk.h | 12 ------------ drivers/md/dm-io.c | 2 +- include/linux/completion.h | 1 + kernel/sched/completion.c | 20 ++++++++++++++++++++ 6 files changed, 24 insertions(+), 15 deletions(-) Index: linux-2.6/block/blk.h =================================================================== --- linux-2.6.orig/block/blk.h 2024-04-17 18:41:50.000000000 +0200 +++ linux-2.6/block/blk.h 2024-04-17 18:41:50.000000000 +0200 @@ -72,18 +72,6 @@ static inline int bio_queue_enter(struct return __bio_queue_enter(q, bio); } -static inline void blk_wait_io(struct completion *done) -{ - /* Prevent hang_check timer from firing at us during very long I/O */ - unsigned long timeout = sysctl_hung_task_timeout_secs * HZ / 2; - - if (timeout) - while (!wait_for_completion_io_timeout(done, timeout)) - ; - else - wait_for_completion_io(done); -} - #define BIO_INLINE_VECS 4 struct bio_vec *bvec_alloc(mempool_t *pool, unsigned short *nr_vecs, gfp_t gfp_mask); Index: linux-2.6/drivers/md/dm-io.c =================================================================== --- linux-2.6.orig/drivers/md/dm-io.c 2024-04-17 18:41:50.000000000 +0200 +++ linux-2.6/drivers/md/dm-io.c 2024-04-17 18:41:50.000000000 +0200 @@ -450,7 +450,7 @@ static int sync_io(struct dm_io_client * dispatch_io(opf, num_regions, where, dp, io, 1, ioprio); - wait_for_completion_io(&sio.wait); + wait_for_completion_long_io(&sio.wait); if (error_bits) *error_bits = sio.error_bits; Index: linux-2.6/include/linux/completion.h =================================================================== --- linux-2.6.orig/include/linux/completion.h 2024-04-17 18:41:50.000000000 +0200 +++ linux-2.6/include/linux/completion.h 2024-04-17 18:49:07.000000000 +0200 @@ -112,6 +112,7 @@ extern long wait_for_completion_interrup struct completion *x, unsigned long timeout); extern long wait_for_completion_killable_timeout( struct completion *x, unsigned long timeout); +extern void wait_for_completion_long_io(struct completion *x); extern bool try_wait_for_completion(struct completion *x); extern bool completion_done(struct completion *x); Index: linux-2.6/block/bio.c =================================================================== --- linux-2.6.orig/block/bio.c 2024-04-17 18:41:50.000000000 +0200 +++ linux-2.6/block/bio.c 2024-04-17 18:41:50.000000000 +0200 @@ -1378,7 +1378,7 @@ int submit_bio_wait(struct bio *bio) bio->bi_end_io = submit_bio_wait_endio; bio->bi_opf |= REQ_SYNC; submit_bio(bio); - blk_wait_io(&done); + wait_for_completion_long_io(&done); return blk_status_to_errno(bio->bi_status); } Index: linux-2.6/block/blk-mq.c =================================================================== --- linux-2.6.orig/block/blk-mq.c 2024-04-17 18:41:50.000000000 +0200 +++ linux-2.6/block/blk-mq.c 2024-04-17 18:41:50.000000000 +0200 @@ -1407,7 +1407,7 @@ blk_status_t blk_execute_rq(struct reque if (blk_rq_is_poll(rq)) blk_rq_poll_completion(rq, &wait.done); else - blk_wait_io(&wait.done); + wait_for_completion_long_io(&wait.done); return wait.ret; } Index: linux-2.6/kernel/sched/completion.c =================================================================== --- linux-2.6.orig/kernel/sched/completion.c 2024-04-17 18:41:50.000000000 +0200 +++ linux-2.6/kernel/sched/completion.c 2024-04-17 18:41:50.000000000 +0200 @@ -290,6 +290,26 @@ wait_for_completion_killable_timeout(str EXPORT_SYMBOL(wait_for_completion_killable_timeout); /** + * wait_for_completion_long_io - waits for completion of a task + * @x: holds the state of this particular completion + * + * This is like wait_for_completion_io, but it doesn't warn if the wait takes + * too long. + */ +void wait_for_completion_long_io(struct completion *x) +{ + /* Prevent hang_check timer from firing at us during very long I/O */ + unsigned long timeout = sysctl_hung_task_timeout_secs * HZ / 2; + + if (timeout) + while (!wait_for_completion_io_timeout(x, timeout)) + ; + else + wait_for_completion_io(x); +} +EXPORT_SYMBOL(wait_for_completion_long_io); + +/** * try_wait_for_completion - try to decrement a completion without blocking * @x: completion structure *