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From: Michal Hocko <mhocko@kernel.org>
To: Zi Yan <zi.yan@cs.rutgers.edu>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	"Kirill A . Shutemov" <kirill@shutemov.name>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	Hugh Dickins <hughd@google.com>
Subject: Re: [PATCH] Lock mmap_sem when calling migrate_pages() in do_move_pages_to_node()
Date: Wed, 31 Jan 2018 09:01:14 +0100	[thread overview]
Message-ID: <20180131080114.GM21609@dhcp22.suse.cz> (raw)
In-Reply-To: <F3D5C6AC-78B6-4443-9BE1-575831F238E2@cs.rutgers.edu>

On Tue 30-01-18 14:12:28, Zi Yan wrote:
> On 30 Jan 2018, at 11:10, Michal Hocko wrote:
[...]
> I think the question is whether we need to hold mmap_sem for
> migrate_pages(). Hugh also agrees it is not necessary on a separate
> email. But it is held in the original code.

I would be really surprised if we really needed the lock. If we do,
however, then we really need a very good explanation why. The code used
to do so is not a valid reason.

-- 
Michal Hocko
SUSE Labs

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      reply	other threads:[~2018-01-31  8:01 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-30  3:00 Zi Yan
2018-01-30  4:10 ` Hugh Dickins
2018-01-30 15:56   ` Zi Yan
2018-01-30  8:14 ` Michal Hocko
2018-01-30 15:52   ` Zi Yan
2018-01-30 16:10     ` Michal Hocko
2018-01-30 19:12       ` Zi Yan
2018-01-31  8:01         ` Michal Hocko [this message]

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