From: Andrew Morton <akpm@linux-foundation.org>
To: Michal Hocko <mhocko@suse.cz>
Cc: linux-mm@kvack.org, Cyril Hrubis <chrubis@suse.cz>,
Hugh Dickins <hughd@google.com>,
Michel Lespinasse <walken@google.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Rik van Riel <riel@redhat.com>,
Michael Kerrisk <mtk.manpages@gmail.com>,
LKML <linux-kernel@vger.kernel.org>,
Linux API <linux-api@vger.kernel.org>
Subject: Re: [RFC 1/3] mm: mmap make MAP_LOCKED really mlock semantic
Date: Tue, 28 Apr 2015 16:10:01 -0700 [thread overview]
Message-ID: <20150428161001.e854fb3eaf82f738865130af@linux-foundation.org> (raw)
In-Reply-To: <1430223111-14817-2-git-send-email-mhocko@suse.cz>
On Tue, 28 Apr 2015 14:11:49 +0200 Michal Hocko <mhocko@suse.cz> wrote:
> The man page however says
> "
> MAP_LOCKED (since Linux 2.5.37)
> Lock the pages of the mapped region into memory in the manner of
> mlock(2). This flag is ignored in older kernels.
> "
I'm trying to remember why we implemented MAP_LOCKED in the first
place. Was it better than mmap+mlock in some fashion?
afaict we had a #define MAP_LOCKED in the header file but it wasn't
implemented, so we went and wired it up. 13 years ago:
https://lkml.org/lkml/2002/9/18/108
Anyway... the third way of doing this is to use plain old mmap() while
mlockall(MCL_FUTURE) is in force. Has anyone looked at that, checked
that the behaviour is sane and compared it with the mmap+mlock
behaviour, the MAP_LOCKED behaviour and the manpages?
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next prev parent reply other threads:[~2015-04-28 23:10 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-14 9:50 Should mmap MAP_LOCKED fail if mm_poppulate fails? Michal Hocko
2015-04-28 12:11 ` Michal Hocko
2015-04-28 12:11 ` [RFC 1/3] mm: mmap make MAP_LOCKED really mlock semantic Michal Hocko
2015-04-28 23:10 ` Andrew Morton [this message]
2015-04-29 7:52 ` Michal Hocko
2015-04-28 12:11 ` [RFC 2/3] mm: allow munmap related functions to understand gfp_mask Michal Hocko
2015-04-28 12:11 ` [RFC 3/3] mm: introduce do_munmap_nofail Michal Hocko
2015-04-28 16:01 ` Should mmap MAP_LOCKED fail if mm_poppulate fails? Linus Torvalds
2015-04-28 16:43 ` Michal Hocko
2015-04-28 16:57 ` Linus Torvalds
2015-04-28 18:35 ` Michal Hocko
2015-04-28 18:38 ` Linus Torvalds
2015-04-28 20:36 ` Michal Hocko
2015-04-29 11:38 ` [RFC PATCH] mmap.2: clarify MAP_LOCKED semantic (was: Re: Should mmap MAP_LOCKED fail if mm_poppulate fails?) Michal Hocko
2015-04-30 0:28 ` David Rientjes
2015-04-30 14:52 ` Michal Hocko
2015-05-06 12:21 ` Michal Hocko
2015-04-28 20:21 ` Should mmap MAP_LOCKED fail if mm_poppulate fails? Michal Hocko
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