Re: [PATCH v2] fs-writeback: writeback_sb_inodes：Recalculate 'wrote' according skipped pages

[Peter Zijlstra]

On Mon, Apr 18, 2022 at 12:43:43PM -0700, Linus Torvalds wrote:
> Which all brings us back to how we have that hacky thing in
> writeback_sb_inodes() that does
> 
>         if (need_resched()) {
>                 /*
>                  * We're trying to balance between building up a nice
>                  * long list of IOs to improve our merge rate, and
>                  * getting those IOs out quickly for anyone throttling
>                  * in balance_dirty_pages().  cond_resched() doesn't
>                  * unplug, so get our IOs out the door before we
>                  * give up the CPU.
>                  */
>                 blk_flush_plug(current->plug, false);
>                 cond_resched();
>         }

Yeah, that's horribly broken for PREEMPT=y.