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From: Matthew Wilcox <willy@infradead.org>
To: Yu Kuai <yukuai3@huawei.com>
Cc: akpm@linux-foundation.org, kent.overstreet@gmail.com,
	axboe@kernel.dk, linux-fsdevel@vger.kernel.org,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	yi.zhang@huawei.com
Subject: Re: [PATCH -next] mm/filemap: fix that first page is not mark accessed in filemap_read()
Date: Thu, 2 Jun 2022 19:30:47 +0100	[thread overview]
Message-ID: <YpkB1+PwIZ3AKUqg@casper.infradead.org> (raw)
In-Reply-To: <20220602082129.2805890-1-yukuai3@huawei.com>

On Thu, Jun 02, 2022 at 04:21:29PM +0800, Yu Kuai wrote:
> In filemap_read(), 'ra->prev_pos' is set to 'iocb->ki_pos + copied',
> while it should be 'iocb->ki_ops'.

Can you walk me through your reasoning which leads you to believe that
it should be ki_pos instead of ki_pos + copied?  As I understand it,
prev_pos is the end of the previous read, not the beginning of the
previous read.

For consequence,
> folio_mark_accessed() will not be called for 'fbatch.folios[0]' since
> 'iocb->ki_pos' is always equal to 'ra->prev_pos'.

I don't follow this, but maybe I'm just being slow.

  parent reply	other threads:[~2022-06-02 18:30 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-06-02  8:21 [PATCH -next] mm/filemap: fix that first page is not mark accessed in filemap_read() Yu Kuai
2022-06-02 18:22 ` Andrew Morton
2022-06-06  1:11   ` Yu Kuai
2022-06-02 18:30 ` Matthew Wilcox [this message]
2022-06-06  1:10   ` Yu Kuai
2022-06-10 14:34     ` Matthew Wilcox
2022-06-10 14:36       ` Matthew Wilcox
2022-06-10 17:23         ` Kent Overstreet
2022-06-10 17:47         ` Kent Overstreet
2022-06-10 18:34           ` Matthew Wilcox
2022-06-10 18:48             ` Kent Overstreet
2022-06-11  8:23             ` Yu Kuai
2022-06-11 17:42               ` Matthew Wilcox
2022-06-13  1:31                 ` Yu Kuai
2022-06-09  0:59 ` Yu Kuai
2022-06-15  8:36 ` [mm/filemap] 8b157c14b5: phoronix-test-suite.fio.SequentialRead.LinuxAIO.Yes.Yes.4KB.DefaultTestDirectory.mb_s -8.1% regression kernel test robot

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