lkml.org 
[lkml]   [2022]   [Mar]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: Different writeback timing since v5.14
Jan,

----- Ursprüngliche Mail -----
> Von: "Jan Kara" <jack@suse.cz>
>> Is this expected?
>> Just want to make sure that the said commit didn't uncover an UBIFS issue.
>
> Yes, I think it is expected. Likely the background threshold for UBIFS bdi
> is very small (probably UBIFS is not used much for writeback compared to
> other filesystems). Previously, we just used wb_stat() which returned 0
> (PCP counter inexact value) and so background writeback didn't trigger. Now
> we use wb_stat_sum() when threshold is small, get exact value of dirty
> pages and decide to start background writeback.

Thanks for the prompt reply!

> The only thing is, whether it is really expected that the threshold for
> UBIFS bdi is so small. You can check the values in
> /sys/kernel/debug/bdi/<bdi>/stats.

BdiDirtyThresh is indeed 0.

BdiWriteback: 0 kB
BdiReclaimable: 0 kB
BdiDirtyThresh: 0 kB
DirtyThresh: 772620 kB
BackgroundThresh: 385836 kB
BdiDirtied: 0 kB
BdiWritten: 0 kB
BdiWriteBandwidth: 102400 kBps
b_dirty: 0
b_io: 0
b_more_io: 0
b_dirty_time: 0
bdi_list: 1
state: 1

Thanks,
//richard

\
 
 \ /
  Last update: 2022-03-01 16:07    [W:0.059 / U:0.140 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site