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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 3/3] iomap: use filemap_range_needs_writeback() for O_DIRECT reads
Date: Wed, 24 Feb 2021 18:25:24 +0100	[thread overview]
Message-ID: <20210224172524.GF849@quack2.suse.cz> (raw)
In-Reply-To: <20210224164455.1096727-4-axboe@kernel.dk>

On Wed 24-02-21 09:44:55, Jens Axboe wrote:
> For reads, use the better variant of checking for the need to call
> filemap_write_and_wait_range() when doing O_DIRECT. 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>

Looks good to me. Feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza

> ---
>  fs/iomap/direct-io.c | 24 ++++++++++++++++--------
>  1 file changed, 16 insertions(+), 8 deletions(-)
> 
> diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c
> index e2c4991833b8..8c35a0041f0f 100644
> --- a/fs/iomap/direct-io.c
> +++ b/fs/iomap/direct-io.c
> @@ -487,12 +487,28 @@ __iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
>  		if (pos >= dio->i_size)
>  			goto out_free_dio;
>  
> +		if (iocb->ki_flags & IOCB_NOWAIT) {
> +			if (filemap_range_needs_writeback(mapping, pos, end)) {
> +				ret = -EAGAIN;
> +				goto out_free_dio;
> +			}
> +			iomap_flags |= IOMAP_NOWAIT;
> +		}
> +
>  		if (iter_is_iovec(iter))
>  			dio->flags |= IOMAP_DIO_DIRTY;
>  	} else {
>  		iomap_flags |= IOMAP_WRITE;
>  		dio->flags |= IOMAP_DIO_WRITE;
>  
> +		if (iocb->ki_flags & IOCB_NOWAIT) {
> +			if (filemap_range_has_page(mapping, pos, end)) {
> +				ret = -EAGAIN;
> +				goto out_free_dio;
> +			}
> +			iomap_flags |= IOMAP_NOWAIT;
> +		}
> +
>  		/* for data sync or sync, we need sync completion processing */
>  		if (iocb->ki_flags & IOCB_DSYNC)
>  			dio->flags |= IOMAP_DIO_NEED_SYNC;
> @@ -507,14 +523,6 @@ __iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
>  			dio->flags |= IOMAP_DIO_WRITE_FUA;
>  	}
>  
> -	if (iocb->ki_flags & IOCB_NOWAIT) {
> -		if (filemap_range_has_page(mapping, pos, end)) {
> -			ret = -EAGAIN;
> -			goto out_free_dio;
> -		}
> -		iomap_flags |= IOMAP_NOWAIT;
> -	}
> -
>  	if (dio_flags & IOMAP_DIO_OVERWRITE_ONLY) {
>  		ret = -EAGAIN;
>  		if (pos >= dio->i_size || pos + count > dio->i_size)
> -- 
> 2.30.0
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

  reply	other threads:[~2021-02-24 17:26 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
2021-02-24 16:44 ` [PATCH 3/3] iomap: " Jens Axboe
2021-02-24 17:25   ` Jan Kara [this message]
  -- 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 3/3] iomap: use filemap_range_needs_writeback() for " Jens Axboe
2021-02-09  7:51   ` Christoph Hellwig
2021-02-09 14:29     ` Jens Axboe

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