linux-kernel - Re: [RFC][PATCH] cifs: Fix cifs_writepages

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Message-ID: <2385284.1677259167@warthog.procyon.org.uk>
Date:   Fri, 24 Feb 2023 17:19:27 +0000
From:   David Howells <dhowells@...hat.com>
To:     Linus Torvalds <torvalds@...ux-foundation.org>
Cc:     dhowells@...hat.com, Steve French <stfrench@...rosoft.com>,
        Vishal Moola <vishal.moola@...il.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Jan Kara <jack@...e.cz>, Paulo Alcantara <pc@....nz>,
        Matthew Wilcox <willy@...radead.org>,
        Huang Ying <ying.huang@...el.com>,
        Baolin Wang <baolin.wang@...ux.alibaba.com>,
        Xin Hao <xhao@...ux.alibaba.com>, linux-mm@...ck.org,
        mm-commits@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [RFC][PATCH] cifs: Fix cifs_writepages_region()

Linus Torvalds <torvalds@...ux-foundation.org> wrote:

> Can you humor me, and try if just removing that skip count thing
> instead? IOW, this attached patch?

That works too.

> Because that whole "let's stop writing if we need to reschedule" sounds
> truly odd (we have a cond_resched(), although it's per folio batch, not
> per-folio), and the skip count logic doesn't make much sense to me either.

The skip thing, in my code, is only used in WB_SYNC_NONE mode.  If we hit 5
things in progress or rescheduling is required, we return to the caller on the
basis that conflicting flushes appear to be happening in other threads.

David