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From: Johannes Weiner <hannes@cmpxchg.org>
To: Josef Bacik <josef@toxicpanda.com>
Cc: kernel-team@fb.com, linux-kernel@vger.kernel.org, tj@kernel.org,
	david@fromorbit.com, akpm@linux-foundation.org,
	linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
	riel@redhat.com, jack@suse.cz
Subject: Re: [PATCH 2/4] filemap: kill page_cache_read usage in filemap_fault
Date: Wed, 5 Dec 2018 13:52:09 -0800	[thread overview]
Message-ID: <20181205215209.GA13938@cmpxchg.org> (raw)
In-Reply-To: <20181130195812.19536-3-josef@toxicpanda.com>

On Fri, Nov 30, 2018 at 02:58:10PM -0500, Josef Bacik wrote:
> If we do not have a page at filemap_fault time we'll do this weird
> forced page_cache_read thing to populate the page, and then drop it
> again and loop around and find it.  This makes for 2 ways we can read a
> page in filemap_fault, and it's not really needed.  Instead add a
> FGP_FOR_MMAP flag so that pagecache_get_page() will return a unlocked
> page that's in pagecache.  Then use the normal page locking and readpage
> logic already in filemap_fault.  This simplifies the no page in page
> cache case significantly.
> 
> Signed-off-by: Josef Bacik <josef@toxicpanda.com>

That's a great simplification. Looks correct to me.

Acked-by: Johannes Weiner <hannes@cmpxchg.org>

  reply	other threads:[~2018-12-05 21:52 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-30 19:58 [PATCH 0/4][V4] drop the mmap_sem when doing IO in the fault path Josef Bacik
2018-11-30 19:58 ` [PATCH 1/4] mm: infrastructure for page fault page caching Josef Bacik
2018-12-04 22:49   ` Andrew Morton
2018-11-30 19:58 ` [PATCH 2/4] filemap: kill page_cache_read usage in filemap_fault Josef Bacik
2018-12-05 21:52   ` Johannes Weiner [this message]
2018-12-07  9:57   ` Jan Kara
2018-12-07 10:37     ` Jan Kara
2018-11-30 19:58 ` [PATCH 3/4] filemap: drop the mmap_sem for all blocking operations Josef Bacik
2018-12-04 22:50   ` Andrew Morton
2018-12-05 22:23   ` Johannes Weiner
2018-12-07 11:01   ` Jan Kara
2018-12-10 18:44     ` Josef Bacik
2018-12-11  9:40       ` Jan Kara
2018-12-11 16:08         ` Josef Bacik
2018-12-11 16:38           ` Jan Kara
2018-11-30 19:58 ` [PATCH 4/4] mm: use the cached page for filemap_fault Josef Bacik
2018-12-04 22:50   ` Andrew Morton
2018-12-05 14:58     ` Josef Bacik
2018-12-07 11:03       ` Jan Kara
2018-12-04 22:49 ` [PATCH 0/4][V4] drop the mmap_sem when doing IO in the fault path Andrew Morton
2018-12-06 22:24   ` Dave Chinner

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