From: Jens Axboe <jens.axboe@oracle.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org, ming.m.lin@intel.com,
torvalds@linux-foundation.org, stable@kernel.org
Subject: Re: [PATCH] Properly notify block layer of sync writes
Date: Wed, 2 Jul 2008 10:37:52 +0200 [thread overview]
Message-ID: <20080702083752.GI20055@kernel.dk> (raw)
In-Reply-To: <20080701163949.d0cdf740.akpm@linux-foundation.org>
On Tue, Jul 01 2008, Andrew Morton wrote:
> On Fri, 27 Jun 2008 15:18:31 +0200
> Jens Axboe <jens.axboe@oracle.com> wrote:
>
> > Hi,
> >
> > fsync_buffers_list() and sync_dirty_buffer() both issue async writes and
> > then immediately wait on them. Conceptually, that makes them sync writes
> > and we should treat them as such so that the IO schedulers can handle
> > them appropriately.
> >
> > This patch fixes a write starvation issue that Lin Ming reported, where
> > xx is stuck for more than 2 minutes because of a large number of
> > synchronous IO in the system:
> >
> > INFO: task kjournald:20558 blocked for more than 120 seconds.
> > "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this
> > message.
> > kjournald D ffff810010820978 6712 20558 2
> > ffff81022ddb1d10 0000000000000046 ffff81022e7baa10 ffffffff803ba6f2
> > ffff81022ecd0000 ffff8101e6dc9160 ffff81022ecd0348 000000008048b6cb
> > 0000000000000086 ffff81022c4e8d30 0000000000000000 ffffffff80247537
> > Call Trace:
> > [<ffffffff803ba6f2>] kobject_get+0x12/0x17
> > [<ffffffff80247537>] getnstimeofday+0x2f/0x83
> > [<ffffffff8029c1ac>] sync_buffer+0x0/0x3f
> > [<ffffffff8066d195>] io_schedule+0x5d/0x9f
> > [<ffffffff8029c1e7>] sync_buffer+0x3b/0x3f
> > [<ffffffff8066d3f0>] __wait_on_bit+0x40/0x6f
> > [<ffffffff8029c1ac>] sync_buffer+0x0/0x3f
> > [<ffffffff8066d48b>] out_of_line_wait_on_bit+0x6c/0x78
> > [<ffffffff80243909>] wake_bit_function+0x0/0x23
> > [<ffffffff8029e3ad>] sync_dirty_buffer+0x98/0xcb
> > [<ffffffff8030056b>] journal_commit_transaction+0x97d/0xcb6
> > [<ffffffff8023a676>] lock_timer_base+0x26/0x4b
> > [<ffffffff8030300a>] kjournald+0xc1/0x1fb
> > [<ffffffff802438db>] autoremove_wake_function+0x0/0x2e
> > [<ffffffff80302f49>] kjournald+0x0/0x1fb
> > [<ffffffff802437bb>] kthread+0x47/0x74
> > [<ffffffff8022de51>] schedule_tail+0x28/0x5d
> > [<ffffffff8020cac8>] child_rip+0xa/0x12
> > [<ffffffff80243774>] kthread+0x0/0x74
> > [<ffffffff8020cabe>] child_rip+0x0/0x12
> >
> > Lin Ming confirms that this patch fixes the issue. I've run tests with
> > it for the past week and no ill effects have been observed, so I'm
> > proposing it for inclusion into 2.6.26.
>
> I expect we'll be wanting this in 2.6.25.x also?
Yeah, I think so.
--
Jens Axboe
prev parent reply other threads:[~2008-07-02 8:38 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-06-27 13:18 [PATCH] Properly notify block layer of sync writes Jens Axboe
2008-07-01 23:39 ` Andrew Morton
2008-07-02 8:37 ` Jens Axboe [this message]
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