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From: Minchan Kim <minchan@kernel.org>
To: Jan Kara <jack@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	linux-mm@kvack.org, Josef Bacik <josef@toxicpanda.com>,
	Robert Stupp <snazy@gmx.de>
Subject: Re: [PATCH] mm: Don't bother dropping mmap_sem for zero size readahead
Date: Wed, 12 Feb 2020 08:16:43 -0800	[thread overview]
Message-ID: <20200212161643.GA93795@google.com> (raw)
In-Reply-To: <20200212101356.30759-1-jack@suse.cz>

On Wed, Feb 12, 2020 at 11:13:56AM +0100, Jan Kara wrote:
> When handling a page fault, we drop mmap_sem to start async readahead so
> that we don't block on IO submission with mmap_sem held.  However
> there's no point to drop mmap_sem in case readahead is disabled. Handle
> that case to avoid pointless dropping of mmap_sem and retrying the
> fault. This was actually reported to block mlockall(MCL_CURRENT)
> indefinitely.
> 
> Fixes: 6b4c9f446981 ("filemap: drop the mmap_sem for all blocking operations")
> Reported-by: Minchan Kim <minchan@kernel.org>
> Reported-by: Robert Stupp <snazy@gmx.de>
> Signed-off-by: Jan Kara <jack@suse.cz>

Reveiewed-by: Minchan Kim <minchan@kernel.org>


  parent reply	other threads:[~2020-02-12 16:16 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-12 10:13 [PATCH] mm: Don't bother dropping mmap_sem for zero size readahead Jan Kara
2020-02-12 14:13 ` Josef Bacik
2020-02-12 16:16 ` Minchan Kim [this message]
2020-07-30 11:34 ` SeongJae Park
2020-08-01 10:39   ` Greg KH

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