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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

  parent reply	other threads:[~2021-02-24 17:24 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 " 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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