From: Pekka Enberg <penberg@kernel.org>
To: Colin Cross <ccross@android.com>
Cc: linux-kernel@vger.kernel.org,
Kyungmin Park <kmpark@infradead.org>,
Christoph Hellwig <hch@infradead.org>,
John Stultz <john.stultz@linaro.org>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Dave Hansen <dave.hansen@intel.com>,
Rob Landley <rob@landley.net>,
Andrew Morton <akpm@linux-foundation.org>,
Cyrill Gorcunov <gorcunov@openvz.org>,
David Rientjes <rientjes@google.com>,
Davidlohr Bueso <dave@gnu.org>, Kees Cook <keescook@chromium.org>,
Al Viro <viro@zeniv.linux.org.uk>,
Hugh Dickins <hughd@google.com>, Mel Gorman <mgorman@suse.de>,
Michel Lespinasse <walken@google.com>,
Rik van Riel <riel@redhat.com>,
Konstantin Khlebnikov <khlebnikov@openvz.org>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
David Howells <dhowells@redhat.com>,
Arnd Bergmann <arnd@arndb.de>, Dave Jones <davej@redhat.com>,
"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
Oleg Nesterov <oleg@redhat.com>, Shaohua Li <shli@fusionio.com>,
Sasha Levin <sasha.levin@oracle.com>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Ingo Molnar <mingo@kernel.org>,
linux-doc@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH 2/2] mm: add a field to store names for private anonymous memory
Date: Fri, 12 Jul 2013 08:43:48 +0300 [thread overview]
Message-ID: <51DF9794.4010000@kernel.org> (raw)
In-Reply-To: <1373596462-27115-2-git-send-email-ccross@android.com>
On 07/12/2013 05:34 AM, Colin Cross wrote:
> Userspace processes often have multiple allocators that each do
> anonymous mmaps to get memory. When examining memory usage of
> individual processes or systems as a whole, it is useful to be
> able to break down the various heaps that were allocated by
> each layer and examine their size, RSS, and physical memory
> usage.
>
> This patch adds a user pointer to the shared union in
> vm_area_struct that points to a null terminated string inside
> the user process containing a name for the vma. vmas that
> point to the same address will be merged, but vmas that
> point to equivalent strings at different addresses will
> not be merged.
>
> Userspace can set the name for a region of memory by calling
> prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, start, len, (unsigned long)name);
> Setting the name to NULL clears it.
>
> The names of named anonymous vmas are shown in /proc/pid/maps
> as [anon:<name>] and in /proc/pid/smaps in a new "Name" field
> that is only present for named vmas. If the userspace pointer
> is no longer valid all or part of the name will be replaced
> with "<fault>".
>
> The idea to store a userspace pointer to reduce the complexity
> within mm (at the expense of the complexity of reading
> /proc/pid/mem) came from Dave Hansen. This results in no
> runtime overhead in the mm subsystem other than comparing
> the anon_name pointers when considering vma merging. The pointer
> is stored in a union with fieds that are only used on file-backed
> mappings, so it does not increase memory usage.
>
> Signed-off-by: Colin Cross <ccross@android.com>
So how does this perform if I do prctl(PR_SET_VMA_ANON_NAME)
for thousands of relatively small (max 1 KB) JIT generated
functions? Will we run into MM problems because the VMAs are
not mergeable?
Pekka
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next prev parent reply other threads:[~2013-07-12 5:43 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-12 2:34 [PATCH 1/2] mm: rearrange madvise code to allow for reuse Colin Cross
2013-07-12 2:34 ` [PATCH 2/2] mm: add a field to store names for private anonymous memory Colin Cross
2013-07-12 5:39 ` Pekka Enberg
2013-07-12 8:13 ` Peter Zijlstra
2013-07-12 8:17 ` Peter Zijlstra
2013-07-12 8:44 ` Ingo Molnar
2013-07-12 8:55 ` Pekka Enberg
2013-07-12 9:00 ` Peter Zijlstra
2013-07-12 9:15 ` Ingo Molnar
2013-07-12 9:27 ` Peter Zijlstra
2013-07-12 9:40 ` Ingo Molnar
2013-07-12 9:49 ` Peter Zijlstra
2013-07-12 10:01 ` Ingo Molnar
2013-07-12 20:51 ` Colin Cross
2013-09-26 1:24 ` Colin Cross
2013-07-12 8:21 ` Pekka Enberg
2013-07-12 8:55 ` Peter Zijlstra
2013-07-12 9:04 ` Pekka Enberg
2013-07-12 9:14 ` Peter Zijlstra
2013-07-12 9:28 ` Ingo Molnar
2013-07-12 9:26 ` Ingo Molnar
2013-07-12 9:38 ` Pekka Enberg
2013-07-12 9:45 ` Ingo Molnar
2013-07-12 10:09 ` Peter Zijlstra
2013-07-12 5:43 ` Pekka Enberg [this message]
2013-07-12 6:18 ` Colin Cross
2013-07-12 7:03 ` Pekka Enberg
2013-07-12 6:36 ` Dave Hansen
2013-07-12 6:42 ` Colin Cross
2013-07-14 14:11 ` Oleg Nesterov
2013-07-14 19:27 ` Colin Cross
2013-07-14 14:17 ` Oleg Nesterov
2013-07-14 19:34 ` Colin Cross
2013-10-15 1:31 [PATCHv3 1/2] mm: rearrange madvise code to allow for reuse Colin Cross
2013-10-15 1:31 ` [PATCH 2/2] mm: add a field to store names for private anonymous memory Colin Cross
2013-10-15 21:21 ` Andrew Morton
2013-10-15 21:32 ` Dave Hansen
2013-10-15 21:47 ` Colin Cross
2013-10-16 0:33 ` Minchan Kim
2013-10-16 20:00 ` Colin Cross
2013-10-16 20:34 ` Dave Hansen
2013-10-16 20:41 ` Colin Cross
2013-10-17 2:47 ` Minchan Kim
2013-10-30 21:15 ` Colin Cross
2013-11-01 1:30 ` Minchan Kim
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