Re: Call trace in ext4_es_lru_add on 3.10 stable

[Stefan Priebe <s.priebe@profihost.ag>]

Hi,
Am 22.09.2014 18:47, schrieb Theodore Ts'o:
> On Mon, Sep 22, 2014 at 08:56:23AM +0200, Stefan Priebe wrote:
>>> That's not the whole message; you just weren't able to capture it all.
>>> How are you capturing these messages, by the way?  Serial console?
>>
>> Sorry this was an incomplete copy and paste by me.
>>
>> Here is the complete output:
>> [1578544.839610] BUG: soft lockup - CPU#7 stuck for 22s! [mysqld:29281]
>> [1578544.893450] Modules linked in: nf_conntrack_ipv4 nf_defrag_ipv4
>
> OK, thanks, this is a known bug, where when ext4 is under heavy memory
> pressure, we can end up stalling in reclaim.  This message indicates
> that the system got stalled for 22 seconds, which is not good, since
> it impacts the interactivity of your system, and increases the
> long-tail latency of requests to servers running on your system, but
> it doesn't cause any data loss or will cause any of your processes to
> crash or otherwise stop functioning (except for temporarily).
>
> It's something that we are working on, and there are patches which
> Zheng Liu submitted that still need a bit of polishing, but I hope to
> have it addressed soon.

Thanks for your feedback. Will those patches go to stable? Any link to 
those patches?

Stefan

>
> Cheers,
>
> 						- Ted
>