From: Andrew Morton <akpm@linux-foundation.org>
To: Jason Baron <jbaron@akamai.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Michal Hocko <mhocko@suse.com>, Vlastimil Babka <vbabka@suse.cz>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Mel Gorman <mgorman@suse.de>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Subject: Re: [PATCH] mm/madvise: allow MADV_DONTNEED to free memory that is MLOCK_ONFAULT
Date: Fri, 8 Jun 2018 12:57:17 -0700 [thread overview]
Message-ID: <20180608125717.c34d3e7125c62fc91ac427c8@linux-foundation.org> (raw)
In-Reply-To: <1528484212-7199-1-git-send-email-jbaron@akamai.com>
On Fri, 8 Jun 2018 14:56:52 -0400 Jason Baron <jbaron@akamai.com> wrote:
> In order to free memory that is marked MLOCK_ONFAULT, the memory region
> needs to be first unlocked, before calling MADV_DONTNEED. And if the region
> is to be reused as MLOCK_ONFAULT, we require another call to mlock2() with
> the MLOCK_ONFAULT flag.
>
> Let's simplify freeing memory that is set MLOCK_ONFAULT, by allowing
> MADV_DONTNEED to work directly for memory that is set MLOCK_ONFAULT. The
> locked memory limits, tracked by mm->locked_vm do not need to be adjusted
> in this case, since they were charged to the entire region when
> MLOCK_ONFAULT was initially set.
Seems useful.
Is a manpage update planned?
Various updates to tools/testing/selftests/vm/* seem appropriate.
> Further, I don't think allowing MADV_FREE for MLOCK_ONFAULT regions makes
> sense, since the point of MLOCK_ONFAULT is for userspace to know when pages
> are locked in memory and thus to know when page faults will occur.
This sounds non-backward-compatible?
next prev parent reply other threads:[~2018-06-08 19:57 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-08 18:56 Jason Baron
2018-06-08 19:57 ` Andrew Morton [this message]
2018-06-08 20:55 ` Jason Baron
2018-06-09 11:51 ` kbuild test robot
2018-06-11 7:20 ` Michal Hocko
2018-06-11 14:51 ` Jason Baron
2018-06-11 15:03 ` Michal Hocko
2018-06-11 16:23 ` Jason Baron
2018-06-12 7:46 ` Michal Hocko
2018-06-12 14:11 ` Jason Baron
2018-06-13 6:32 ` Vlastimil Babka
2018-06-13 7:15 ` Michal Hocko
2018-06-13 7:51 ` Vlastimil Babka
2018-06-13 8:37 ` Michal Hocko
2018-06-15 19:36 ` Jason Baron
2018-06-20 11:00 ` Michal Hocko
2018-06-28 20:20 ` Jason Baron
2018-06-13 9:13 ` Michal Hocko
2018-06-15 19:28 ` Jason Baron
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