linux-kernel - Re: [PATCH 0/12] Per-bdi writeback flusher threads v7

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Message-Id: <1243402035.2560.127.camel@ymzhang>
Date:	Wed, 27 May 2009 13:27:15 +0800
From:	"Zhang, Yanmin" <yanmin_zhang@...ux.intel.com>
To:	Jens Axboe <jens.axboe@...cle.com>
Cc:	linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
	chris.mason@...cle.com, david@...morbit.com, hch@...radead.org,
	akpm@...ux-foundation.org, jack@...e.cz, richard@....demon.co.uk
Subject: Re: [PATCH 0/12] Per-bdi writeback flusher threads v7

On Tue, 2009-05-26 at 11:33 +0200, Jens Axboe wrote:
> Hi,
> 
> Here's the 7th version of the writeback patches. Changes since
> v5/v6:
> 
> - Move the sync_supers() to the global bdi_forker_task() thread, so we
>   don't writeback the supers from all the bdi kupdated() tasks.
> - Make bdi_start_writeback() and bdi_writeback_all() be sync when called
>   with WB_SYNC_ALL only.
> - Shuffle some more things around to make a cleaner series. The sync vs
>   async nature of bdi_writeback_all() and bdi_start_writeback() isn't
>   consistent through the series, but otherwise things should be sane.
> 
> I'd appreciate if Richard and Yanmin could re-run testing with this,
> just to make sure that things are sane. For ease of patching, I've
> put the full diff here:
> 
>   http://kernel.dk/writeback-v7.patch
I ported it to 2.6.30-rc6 with some change in file mm/page-write.c, so I 
could compare with old data.

See the attachment.

The new testing hits the hang issue again. It seems there is still a race.

INFO: task sync:30013 blocked for more than 120 seconds.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
sync          D ffffc20000011300  4736 30013  28019
 ffffffff8093e350 0000000000000086 0000000000000000 0000000000000000
 0000000000021220 0000000000004000 0000000000011300 000000000000c868
 ffff880000016c48 ffffe20002934b30 ffff8800720b3780 ffff8800720b3b08
Call Trace:
 [<ffffffff802c31d0>] ? bdi_sched_wait+0x0/0xd
 [<ffffffff8071e56f>] ? schedule+0x9/0x1e
 [<ffffffff802c31d9>] ? bdi_sched_wait+0x9/0xd
 [<ffffffff8071eb36>] ? __wait_on_bit+0x41/0x71
 [<ffffffff802c31d0>] ? bdi_sched_wait+0x0/0xd
 [<ffffffff8071ebd1>] ? out_of_line_wait_on_bit+0x6b/0x77
 [<ffffffff8024cc0c>] ? wake_bit_function+0x0/0x23
 [<ffffffff8022cfa1>] ? __wake_up+0x30/0x44
 [<ffffffff802c2e22>] ? bdi_writeback_all+0x20b/0x24c
 [<ffffffff802800ce>] ? pagevec_lookup_tag+0x1a/0x21
 [<ffffffff80279248>] ? wait_on_page_writeback_range+0xce/0x11b
 [<ffffffff802c2ff3>] ? generic_sync_sb_inodes+0x36/0xe1
 [<ffffffff802c3121>] ? sync_inodes_sb+0x83/0x88
 [<ffffffff802c316c>] ? __sync_inodes+0x46/0x8f
 [<ffffffff802c5d10>] ? do_sync+0x36/0x5a
 [<ffffffff802c5d56>] ? sys_sync+0xe/0x14
 [<ffffffff8020ba2b>] ? system_call_fastpath+0x16/0x1b



View attachment "jens_bdi_fluser_v7_2.6.30-rc6.patch" of type "text/x-patch" (81633 bytes)