lkml.org 
[lkml]   [2018]   [Sep]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH] bcache: add separate workqueue for journal_write to avoid deadlock
From
Date
On 27/09/18 16:23, Coly Li wrote:
>
> On 9/27/18 9:45 PM, guoju wrote:
>> After write SSD completed, bcache schedule journal_write work to
>> system_wq, that is a public workqueue in system, without WQ_MEM_RECLAIM
>> flag. system_wq is also a bound wq, and there may be no idle kworker on
>> current processor. Creating a new kworker may unfortunately need to
>> reclaim memory first, by shrinking cache and slab used by vfs, which
>> depends on bcache device. That's a deadlock.
>>
>> This patch create a new workqueue for journal_write with WQ_MEM_RECLAIM
>> flag. It's rescuer thread will work to avoid the deadlock.
>>
>> Signed-off-by: guoju <fangguoju@gmail.com>
>
> Nice catch, this fix is quite important. I will try to submit to Jens ASAP.
>
> Thanks.
>
> Coly Li

Once this goes into 4.19, would this be a candidate for backporting to
any stable kernels, or does it only fix something introduced in this cycle?

thanks,
Eddie

\
 
 \ /
  Last update: 2018-09-27 18:00    [W:0.598 / U:0.016 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site