Re: jbd2: don't wake kjournald unnecessarily

From: Sedat Dilek
Date: Sat Jan 19 2013 - 19:55:08 EST

On Sun, Jan 20, 2013 at 1:35 AM, Sedat Dilek <sedat.dilek@xxxxxxxxx> wrote:
> On Sun, Jan 20, 2013 at 1:06 AM, Sedat Dilek <sedat.dilek@xxxxxxxxx> wrote:
>> On Sun, Jan 20, 2013 at 12:44 AM, Sedat Dilek <sedat.dilek@xxxxxxxxx> wrote:
>>> Hi,
>>>
>>> I and some others hit a similiar problem in Linux-Next
>>> (next-20130118), please see [1] and [2].
>>>
>>> [3] has a interim analyze of my problems.
>>>
>>> After suspecting the problem was caused by TTY-NEXT, it turned out to
>>> be a JBD2 problem finally.
>>> The freezer/pm_test was helpful to hit the issue (Thanks Rafael for the hint!).
>>>
>>> So, the issue has two faces: TTY and JBD2.
>>> [4] gives a list and URLs of the patches I had to apply to have a
>>> clean system again.
>>>
>>> After applying the two TTY patches (without Eric's JBD2-fix!) the
>>> call-trace after freezer/pm_test looked like this;
>>>
>>> [ 433.527986] PM: Syncing filesystems ... done.
>>> [ 433.843761] PM: Preparing system for mem sleep
>>> [ 436.306002] Freezing user space processes ...
>>> [ 456.304956] Freezing of tasks failed after 20.01 seconds (1 tasks
>>> refusing to freeze, wq_busy=0):
>>> [ 456.305060] Cache I/O D ffffffff8180d780 0 2132 1 0x00000004
>>> [ 456.305065] ffff88007b9dfe18 0000000000000046 ffff88007b9dfdc8
>>> 0000000300000001
>>> [ 456.305069] ffff880097e21720 ffff88007b9dffd8 ffff88007b9dffd8
>>> ffff88007b9dffd8
>>> [ 456.305072] ffff880119b32e40 ffff880097e21720 ffff88007b9dfe28
>>> ffff880118077800
>>> [ 456.305076] Call Trace:
>>> [ 456.305085] [<ffffffff816b7469>] schedule+0x29/0x70
>>> [ 456.305089] [<ffffffff8129067d>] jbd2_log_wait_commit+0xcd/0x1a0
>>> [ 456.305094] [<ffffffff8107eac0>] ? add_wait_queue+0x60/0x60
>>> [ 456.305098] [<ffffffff812307a5>] ext4_sync_file+0x205/0x380
>>> [ 456.305103] [<ffffffff811c43ad>] do_fsync+0x5d/0x90
>>> [ 456.305108] [<ffffffff8119442b>] ? sys_write+0x6b/0xa0
>>> [ 456.305111] [<ffffffff811c4790>] sys_fsync+0x10/0x20
>>> [ 456.305114] [<ffffffff816c0edd>] system_call_fastpath+0x1a/0x1f
>>> [ 456.305122]
>>> [ 456.305124] Restarting tasks ... done.
>>> [ 456.315056] video LNXVIDEO:00: Restoring backlight state
>>>
>>> After applying Eric's patch [5], I could not hit the call-trace again.
>>> NOTE: The patch is from December 2012 and is not shipped in latest Linux-Next.
>>>
>>> The attached testcase script was helpful to force the call-trace.
>>> I have run 50 loops of it w/o an issue!
>>>
>>> Feel free to add a Reported-by/Tested-by.
>>> ( The issue kept me busy for the last days. )
>>>
>>> Regards,
>>> - Sedat -
>>>
>>> [1] http://marc.info/?t=135283664600002&r=1&w=2
>>> [2] http://marc.info/?t=135862023700004&r=1&w=2
>>> [3] http://marc.info/?l=linux-kernel&m=135862010419101&w=2
>>> [4] http://marc.info/?l=linux-next&m=135863550923093&w=2
>>> [5] http://patchwork.ozlabs.org/patch/207237/
>>
>> Hi all,
>>
>> this is really ugly... I could cry!
>>
>> GRRR, I have hit the original issue again while running my testcase script!
>>
>> [ 363.831226] PM: Syncing filesystems ... done.
>> [ 363.988855] PM: Preparing system for mem sleep
>> [ 369.032965] Freezing user space processes ... (elapsed 0.11 seconds) done.
>> [ 369.145792] Freezing remaining freezable tasks ...
>> [ 389.137643] Freezing of tasks failed after 20.01 seconds (1 tasks
>> refusing to freeze, wq_busy=0):
>> [ 389.137760] jbd2/loop0-8 D ffffffff8180d780 0 295 2 0x00000000
>> [ 389.137769] ffff8801181dfb68 0000000000000046 ffff880117de5c80
>> 0000000000000001
>> [ 389.137778] ffff880117de5c80 ffff8801181dffd8 ffff8801181dffd8
>> ffff8801181dffd8
>> [ 389.137784] ffffffff81c15440 ffff880117de5c80 ffff8801181dfb68
>> ffff88011fa14738
>> [ 389.137791] Call Trace:
>> [ 389.137810] [<ffffffff811c6830>] ? __wait_on_buffer+0x30/0x30
>> [ 389.137819] [<ffffffff816b7479>] schedule+0x29/0x70
>> [ 389.137825] [<ffffffff816b754f>] io_schedule+0x8f/0xd0
>> [ 389.137832] [<ffffffff811c683e>] sleep_on_buffer+0xe/0x20
>> [ 389.137842] [<ffffffff816b5d4f>] __wait_on_bit+0x5f/0x90
>> [ 389.137849] [<ffffffff811c5ef1>] ? submit_bh+0x121/0x1e0
>> [ 389.137856] [<ffffffff811c6830>] ? __wait_on_buffer+0x30/0x30
>> [ 389.137864] [<ffffffff816b5dfc>] out_of_line_wait_on_bit+0x7c/0x90
>> [ 389.137873] [<ffffffff8107eb00>] ? autoremove_wake_function+0x40/0x40
>> [ 389.137879] [<ffffffff811c682e>] __wait_on_buffer+0x2e/0x30
>> [ 389.137891] [<ffffffff8128c02c>]
>> jbd2_journal_commit_transaction+0x18cc/0x1d60
>> [ 389.137899] [<ffffffff816b860e>] ? _raw_spin_lock_irqsave+0x2e/0x40
>> [ 389.137908] [<ffffffff81069fbf>] ? try_to_del_timer_sync+0x4f/0x70
>> [ 389.137915] [<ffffffff81290836>] kjournald2+0xd6/0x3e0
>> [ 389.137921] [<ffffffff8107eac0>] ? add_wait_queue+0x60/0x60
>> [ 389.137926] [<ffffffff81290760>] ? commit_timeout+0x10/0x10
>> [ 389.137932] [<ffffffff8107ded0>] kthread+0xc0/0xd0
>> [ 389.137939] [<ffffffff8107de10>] ? flush_kthread_worker+0xb0/0xb0
>> [ 389.137946] [<ffffffff816c0e2c>] ret_from_fork+0x7c/0xb0
>> [ 389.137951] [<ffffffff8107de10>] ? flush_kthread_worker+0xb0/0xb0
>> [ 389.138017]
>> [ 389.138021] Restarting kernel threads ... done.
>> [ 389.138173] Restarting tasks ... done.
>> [ 389.147980] video LNXVIDEO:00: Restoring backlight state
>>
>> I suspect there are still issues in JBD2 (BTW I run here EXT4FS).
>>
>> [ 389.137643] Freezing of tasks failed after 20.01 seconds (1 tasks
>> refusing to freeze, wq_busy=0):
>> [ 389.137760] jbd2/loop0-8 D ffffffff8180d780 0 295 2 0x00000000
>>
>> Have a good night, /me -> watching TV!
>>
>> - Sedat -
>
> Man, what a NONSENSE I am telling...
> The mentioned so-called fix is already in next-20130118, shame on me!
>
> commit 7e2fb2d7e6a3094473f101ae33dd6431ae6d2ed1
> "jbd: don't wake kjournald unnecessarily"
>

GNARF, SMASH... that's for JBD.
So Eric's JBD2-fix is really NOT in Linux-Next.
More sleep!

- Sedat -

> - Sedat -
>
> [1] http://git.kernel.org/?p=linux/kernel/git/next/linux-next.git;a=commitdiff;h=7e2fb2d7e6a3094473f101ae33dd6431ae6d2ed1
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