Hi,
On Nov 28, 2012, at 11:59 PM, Piotr Szymaniak wrote:
> On Wed, Nov 28, 2012 at 06:39:20PM +0400, Vyacheslav Dubeyko wrote:
>> On Wed, 2012-11-28 at 15:21 +0100, Piotr Szymaniak wrote:
>>> On Tue, Nov 27, 2012 at 08:43:01PM +0300, Vyacheslav Dubeyko wrote:
>>>> Could you describe the path of issue reproducing? What filesystem
>>>> operations took place near before the issue?
>>>
>>> Reproduce: Use a computer with nilfs2? No idea... I notice this issue
>>> from time to time. I suppose it's more visible when the system is idle
>>> and then I notice a lot of CPU load without any reason (also as I wrote
>>> before - it stops immediately after runnig sync).
>>>
>>
I have reproduced the issue by chance. The reproducibility of the issue is 100%.
The reproducing path is:
1. Generate some file about 100 - 500 GB (for example, by: "dd if=/dev/zero
of=<file_name> bs=1048576 count=102400"). The size of the file defines the
duration of the issue reproducibility.
2. Try to execute "rm", "truncate" or "dd" command. In the case of "dd" it
needs to use without notrunc option (for example, "dd if=/dev/urandom
of=<file_name> bs=1024 seek=51200 count=10").
3. As a result you can see flush kernel thread that uses 60 - 100 % of CPU time
during 5 - 40 minutes:
top - 23:48:53 up 6:11, 15 users, load average: 1.71, 1.16, 1.81
Tasks: 226 total, 3 running, 223 sleeping, 0 stopped, 0 zombie
Cpu(s): 5.3%us, 94.7%sy, 0.0%ni, 0.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 7640788k total, 3991784k used, 3649004k free, 28196k buffers
Swap: 1952764k total, 0k used, 1952764k free, 3126224k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
12358 root 20 0 99484 668 544 R 97 0.0 0:55.27 dd
3027 root 20 0 0 0 0 R 87 0.0 31:46.94 flush-8:32
I suspect the nilfs_mdt_write_page() but I need a more time for the issue
investigation.
With the best regards,
Vyacheslav Dubeyko.
>> Ok. Could you share output of "top" and "ps ax" for the case of issue
>> reproducing? These outputs can be helpful for beginning of analysis.
>
> Already attached [1] "ps ax" output before. Don't know if top can get
> something usefull here, but I can try to "catch" it.
>
> [1] http://www.spinics.net/lists/linux-nilfs/msg01481.html
>
> Piotr Szymaniak.
> --
> Moim jedynym bogiem jest wódka. Moi święci to marki, franki i dolary.
> Jedyna świątynia, którą odwiedzam, to pochwa kobiety. A mój sakrament
> to pieprzenie.
> -- Nelson DeMille, "The Lion's Game"
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