Messages in this thread | | | Date | Tue, 1 Mar 2022 16:05:54 +0100 (CET) | From | Richard Weinberger <> | Subject | Re: Different writeback timing since v5.14 |
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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
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