From: "Theodore Y. Ts'o" <tytso@mit.edu>
To: Jens Axboe <axboe@kernel.dk>
Cc: linux-fsdevel@vger.kernel.org, viro@zeniv.linux.org.uk,
akpm@linux-foundation.org
Subject: Re: [PATCH 3/3] ext4: readpages() should submit IO as read-ahead
Date: Thu, 24 May 2018 16:47:30 -0400 [thread overview]
Message-ID: <20180524204730.GC7712@thunk.org> (raw)
In-Reply-To: <1527177774-21414-4-git-send-email-axboe@kernel.dk>
On Thu, May 24, 2018 at 10:02:54AM -0600, Jens Axboe wrote:
> a_ops->readpages() is only ever used for read-ahead. Ensure that we
> pass this information down to the block layer.
>
> Signed-off-by: Jens Axboe <axboe@kernel.dk>
> ---
> fs/ext4/readpage.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/ext4/readpage.c b/fs/ext4/readpage.c
> index 9ffa6fad18db..92b28273b223 100644
> --- a/fs/ext4/readpage.c
> +++ b/fs/ext4/readpage.c
> @@ -259,7 +259,7 @@ int ext4_mpage_readpages(struct address_space *mapping,
> bio->bi_iter.bi_sector = blocks[0] << (blkbits - 9);
> bio->bi_end_io = mpage_end_io;
> bio->bi_private = ctx;
> - bio_set_op_attrs(bio, REQ_OP_READ, 0);
> + bio_set_op_attrs(bio, REQ_OP_READ, REQ_RAHEAD);
> }
The problem is that ext4_readpage() also calls ext4_mpage_readpages().
So you can't set REQ_RAHEAD unconditionally here.
- Ted
next prev parent reply other threads:[~2018-05-24 20:47 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-24 16:02 [PATCHSET 0/3] Submit ->readpages() " Jens Axboe
2018-05-24 16:02 ` [PATCH 1/3] mpage: mpage_readpages() should submit " Jens Axboe
2018-05-24 19:43 ` Andrew Morton
2018-05-24 19:57 ` Matthew Wilcox
2018-05-24 20:24 ` Jens Axboe
2018-05-29 14:36 ` Jens Axboe
2018-05-29 21:59 ` Andrew Morton
2018-05-29 22:18 ` Jens Axboe
2018-05-29 22:37 ` Jens Axboe
2018-05-24 16:02 ` [PATCH 2/3] btrfs: readpages() " Jens Axboe
2018-05-24 16:02 ` [PATCH 3/3] ext4: " Jens Axboe
2018-05-24 20:47 ` Theodore Y. Ts'o [this message]
2018-05-24 20:53 ` Jens Axboe
2018-05-24 21:05 ` Jens Axboe
2018-05-25 8:32 ` [PATCHSET 0/3] Submit ->readpages() " Christoph Hellwig
2018-05-25 14:21 ` Jens Axboe
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