From: Michal Hocko <mhocko-AlSwsSmVLrQ@public.gmane.org>
To: linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org
Cc: Cyril Hrubis <chrubis-AlSwsSmVLrQ@public.gmane.org>,
Andrew Morton
<akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>,
Hugh Dickins <hughd-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>,
Michel Lespinasse
<walken-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>,
Linus Torvalds
<torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>,
Rik van Riel <riel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
Michael Kerrisk
<mtk.manpages-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
LKML <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
Linux API <linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
Subject: Re: Should mmap MAP_LOCKED fail if mm_poppulate fails?
Date: Tue, 28 Apr 2015 14:11:48 +0200 [thread overview]
Message-ID: <1430223111-14817-1-git-send-email-mhocko@suse.cz> (raw)
In-Reply-To: <20150114095019.GC4706-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
Hi,
it seems that the initial email got lost (or ignored). I would like to
revive it again. I've cooked up a potential fix to this issue which will
follow as a reply to this email.
The first patch is dumb and straightforward. It should be safe as is and
also good without the follow up 2 patches which try to handle potential
allocation failures in the do_munmap path more gracefully. As we still
do not fail small allocations even the first patch could be simplified
a bit and the retry loop replaced by a BUG_ON right away. But I felt this
would better be done robust.
An obvious alternative would be patching the man pages to mention the
subtle difference between mlock and MAP_LOCKED semantic. I have checked
debian code search and it shown some applications relying on MAP_LOCKED
but I have no idea whether they really require the mlock all-or-nothing
fault in semantic.
Any thoughts, ideas?
next prev parent reply other threads:[~2015-04-28 12:11 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
[not found] ` <20150114095019.GC4706-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2015-04-28 12:11 ` Michal Hocko [this message]
2015-04-28 12:11 ` [RFC 1/3] mm: mmap make MAP_LOCKED really mlock semantic Michal Hocko
[not found] ` <1430223111-14817-2-git-send-email-mhocko-AlSwsSmVLrQ@public.gmane.org>
2015-04-28 23:10 ` Andrew Morton
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
[not found] ` <1430223111-14817-1-git-send-email-mhocko-AlSwsSmVLrQ@public.gmane.org>
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
[not found] ` <CA+55aFydkG-BgZzry5DrTzueVh9VvEcVJdLV8iOyUphQk=0vpw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-04-28 18:35 ` Michal Hocko
[not found] ` <20150428183535.GB30918-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2015-04-28 18:38 ` Linus Torvalds
2015-04-28 20:36 ` Michal Hocko
[not found] ` <CA+55aFyajquhGhw59qNWKGK4dBV0TPmDD7-1XqPo7DZWvO_hPg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
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
[not found] ` <CA+55aFxzLXx=cC309h_tEc-Gkn_zH4ipR7PsefVcE-97Uj066g-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-04-28 20:21 ` Should mmap MAP_LOCKED fail if mm_poppulate fails? Michal Hocko
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