Re: [RCU problem] was VFS: file-max limit 50044 reached

[linux-os (Dick Johnson)]

On Mon, 17 Oct 2005, Eric Dumazet wrote:

> Dipankar Sarma a écrit :
>> On Mon, Oct 17, 2005 at 11:10:04AM +0200, Eric Dumazet wrote:
>>>
>>> Fixing the 'file count' wont fix the real problem : Batch freeing is good
>>> but should be limited so that not more than *billions* of file struct are
>>> queued for deletion.
>>
>>
>> Agreed. It is not designed to work that way, so there must be
>> a bug somewhere and I am trying to track it down. It could very well
>> be that at maxbatch=10 we are just queueing at a rate far too high
>> compared to processing.
>>
>
> I can freeze my test machine with a program that 'only' use dentries,
> no files.
>
> No message, no panic, but machine becomes totally unresponsive after
> few seconds.
>
> Just greping for call_rcu in kernel sources gave me another call_rcu() use
> from syscalls. And yes 2.6.13 has the same problem.
>
> Here is the killer on by HT Xeon machine (2GB ram)
>
> Eric
>

No problem with linux-2.6.13.4 and ext3 file-system:
F   UID   PID  PPID PRI  NI   VSZ  RSS WCHAN  STAT TTY        TIME COMMAND
4     0     1     0  16   0  1544  408 -      S    ?          0:00 init [5]
[SNIPPED....]
1     0 16017     6  15   0     0    0 pdflus SW   ?          0:00 [pdflush]
4   666 16406  5273  16   0  4464 1004 wait   S    tty2       0:00 -bash
0   666 16501 16406  18   0  1324  240 -      R    tty2       9:46 ./xxx
4     0 16502  5223  15   0  4204 1248 wait   S    tty1       0:00 -bash
0     0 16563 16502  16   0  2276  584 -      R    tty1       0:00 ps laxw

I just put 9:46 CPU time on your program and every thing is fine.


Cheers,
Dick Johnson
Penguin : Linux version 2.6.13.4 on an i686 machine (5589.46 BogoMips).
Warning : 98.36% of all statistics are fiction.

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