From: Jan Kara <jack@suse.cz>
To: Jens Axboe <axboe@kernel.dk>
Cc: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
akpm@linux-foundation.org
Subject: Re: [PATCH 2/3] mm: use filemap_range_needs_writeback() for O_DIRECT reads
Date: Wed, 24 Feb 2021 18:23:35 +0100 [thread overview]
Message-ID: <20210224172335.GE849@quack2.suse.cz> (raw)
In-Reply-To: <20210224164455.1096727-3-axboe@kernel.dk>
On Wed 24-02-21 09:44:54, Jens Axboe wrote:
> For the generic page cache read helper, use the better variant of checking
> for the need to call filemap_write_and_wait_range() when doing O_DIRECT
> reads. This avoids falling back to the slow path for IOCB_NOWAIT, if there
> are no pages to wait for (or write out).
>
> Signed-off-by: Jens Axboe <axboe@kernel.dk>
> ---
> mm/filemap.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
Looks good to me. Feel free to add:
Reviewed-by: Jan Kara <jack@suse.cz>
Honza
>
> diff --git a/mm/filemap.c b/mm/filemap.c
> index 13338f877677..77f1b527541e 100644
> --- a/mm/filemap.c
> +++ b/mm/filemap.c
> @@ -2645,8 +2645,8 @@ generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
>
> size = i_size_read(inode);
> if (iocb->ki_flags & IOCB_NOWAIT) {
> - if (filemap_range_has_page(mapping, iocb->ki_pos,
> - iocb->ki_pos + count - 1))
> + if (filemap_range_needs_writeback(mapping, iocb->ki_pos,
> + iocb->ki_pos + count - 1))
> return -EAGAIN;
> } else {
> retval = filemap_write_and_wait_range(mapping,
> --
> 2.30.0
>
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
next prev parent reply other threads:[~2021-02-24 17:23 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-24 16:44 [PATCHSET v3 0/3] Improve IOCB_NOWAIT O_DIRECT reads Jens Axboe
2021-02-24 16:44 ` [PATCH 1/3] mm: provide filemap_range_needs_writeback() helper Jens Axboe
2021-02-24 16:50 ` Matthew Wilcox
2021-02-24 16:53 ` Jens Axboe
2021-02-24 17:22 ` Jan Kara
2021-02-24 16:44 ` [PATCH 2/3] mm: use filemap_range_needs_writeback() for O_DIRECT reads Jens Axboe
2021-02-24 16:57 ` Matthew Wilcox
2021-02-24 17:23 ` Jan Kara [this message]
2021-02-24 16:44 ` [PATCH 3/3] iomap: " Jens Axboe
2021-02-24 17:25 ` Jan Kara
-- strict thread matches above, loose matches on Subject: below --
2021-02-09 2:30 [PATCHSET v2 0/3] Improve IOCB_NOWAIT " Jens Axboe
2021-02-09 2:30 ` [PATCH 2/3] mm: use filemap_range_needs_writeback() for " Jens Axboe
2021-02-09 7:48 ` Christoph Hellwig
2021-02-09 14:27 ` Jens Axboe
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