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

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Message-ID: <CAHk-=whqzkoYZ06Bn0Owy-tQt_jK1uSTFd6awUQAAGK4rysD1Q@mail.gmail.com>
Date:   Mon, 18 Apr 2022 17:24:13 -0700
From:   Linus Torvalds <torvalds@...ux-foundation.org>
To:     Jens Axboe <axboe@...nel.dk>
Cc:     Zhihao Cheng <chengzhihao1@...wei.com>,
        Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Al Viro <viro@...iv.linux.org.uk>,
        Christoph Hellwig <hch@....de>,
        linux-fsdevel <linux-fsdevel@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        yukuai3@...wei.com
Subject: Re: [PATCH v2] fs-writeback: writeback_sb_inodes：Recalculate 'wrote' according skipped pages

On Mon, Apr 18, 2022 at 3:20 PM Jens Axboe <axboe@...nel.dk> wrote:
>
> Here's the thread:
>
> https://lore.kernel.org/all/1295659049-2688-6-git-send-email-jaxboe@fusionio.com/
>
> I'll dig through it in a bit, but here's your reasoning for why it
> should not flush on preemption:
>
> https://lore.kernel.org/all/BANLkTikBEJa7bJJoLFU7NoiEgOjVHVG08A@mail.gmail.com/

Well, that one was triggered by that whole "now it can happen
anywhere" worry that people had.

So yes, IO patterns are a worry, but I think the bigger worry - even
back then - was that preemption points can be pretty much anywhere in
the code.

              Linus