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From: Christoph Hellwig <hch@infradead.org>
To: Jens Axboe <axboe@kernel.dk>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	linux-fsdevel@vger.kernel.org, viro@zeniv.linux.org.uk
Subject: Re: [PATCHSET v3 0/4] Submit ->readpages() IO as read-ahead
Date: Thu, 21 Jun 2018 05:21:16 -0700	[thread overview]
Message-ID: <20180621122116.GA14053@infradead.org> (raw)
In-Reply-To: <df80944e-f8ce-198a-910d-54e0185d8d41@kernel.dk>

On Wed, Jun 20, 2018 at 04:28:54PM -0600, Jens Axboe wrote:
> The assumption has been true for a decade or more. The only problem with
> it is that we have this ->readpages() interface that is only used for
> readahead. Hence it should be ->readahead() or similar, that avoid the
> fragility argument.

Or just stop this whole bike shed.  ->readpages doesn't keep the pages
it reads locked, so it fundamentally is a readahead style operation.

Now if we actually want do to anything with that information is another
question that I already asked in reply to the first round of these
patches.

Especially as e.g. nvme actually sets hints based on the flag, that
if hardware actually ever looked at them might be doing the wrong
thing (fortunately for us I doubt any nvme hardware actually looks
at that flag).

  parent reply	other threads:[~2018-06-21 12:21 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-30 14:42 [PATCHSET v3 0/4] Submit ->readpages() IO as read-ahead Jens Axboe
2018-05-30 14:42 ` [PATCH 1/4] mpage: add argument structure for do_mpage_readpage() Jens Axboe
2018-05-30 14:42 ` [PATCH 2/4] mpage: mpage_readpages() should submit IO as read-ahead Jens Axboe
2018-05-30 14:42 ` [PATCH 3/4] btrfs: readpages() " Jens Axboe
2018-05-30 14:42 ` [PATCH 4/4] ext4: " Jens Axboe
2018-06-19 23:56 ` [PATCHSET v3 0/4] Submit ->readpages() " Andrew Morton
2018-06-20 14:07   ` Jens Axboe
2018-06-20 19:58     ` Andrew Morton
2018-06-20 20:15       ` Chris Mason
2018-06-20 22:28       ` Jens Axboe
2018-06-20 23:23         ` Andrew Morton
2018-06-20 23:33           ` Jens Axboe
2018-06-20 23:45             ` Andrew Morton
2018-06-21  0:06               ` Jens Axboe
2018-06-21 12:21         ` Christoph Hellwig [this message]
2018-06-21 13:52           ` Jens Axboe

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