From: Christoph Hellwig <hch@infradead.org>
To: Jens Axboe <axboe@kernel.dk>
Cc: linux-fsdevel@vger.kernel.org, viro@zeniv.linux.org.uk,
akpm@linux-foundation.org
Subject: Re: [PATCHSET 0/3] Submit ->readpages() IO as read-ahead
Date: Fri, 25 May 2018 01:32:11 -0700 [thread overview]
Message-ID: <20180525083211.GA25442@infradead.org> (raw)
In-Reply-To: <1527177774-21414-1-git-send-email-axboe@kernel.dk>
On Thu, May 24, 2018 at 10:02:51AM -0600, Jens Axboe wrote:
> The only caller of ->readpages() is from read-ahead, yet we don't
> submit IO flagged with REQ_RAHEAD. This means we don't see it in
> blktrace, for instance, which is a shame. We already make assumptions
> about ->readpages() just being for read-ahead in the mpage
> implementation, using readahead_gfp_mask(mapping) as out GFP mask of
> choice.
>
> This small series fixes up mpage_readpages() to submit with
> REQ_RAHEAD, which takes care of file systems using mpage_readpages().
> The last two fixup ext4 and btrfs.
What are the benefits? Any setup where this buys us anything? Any
setup where this actually regressed because drivers/hardware are
doing stupid things with REQ_RAHEAD?
next prev parent reply other threads:[~2018-05-25 8:32 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-24 16:02 [PATCHSET 0/3] Submit ->readpages() IO as read-ahead 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
2018-05-24 20:53 ` Jens Axboe
2018-05-24 21:05 ` Jens Axboe
2018-05-25 8:32 ` Christoph Hellwig [this message]
2018-05-25 14:21 ` [PATCHSET 0/3] Submit ->readpages() " Jens Axboe
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