From: Rik van Riel <riel@redhat.com>
To: Andi Kleen <andi@firstfloor.org>
Cc: linux-mm@kvack.org, Andrea Arcangeli <aarcange@redhat.com>,
tim.c.chen@linux.intel.com, torvalds@linux-foundation.org,
lwoodman@redhat.com, mel@csn.ul.ie,
Andi Kleen <ak@linux.intel.com>
Subject: Re: [PATCH 1/4] VM/RMAP: Add infrastructure for batching the rmap chain locking
Date: Fri, 06 May 2011 11:59:30 -0400 [thread overview]
Message-ID: <4DC41AE2.8060301@redhat.com> (raw)
In-Reply-To: <1304623972-9159-2-git-send-email-andi@firstfloor.org>
On 05/05/2011 03:32 PM, Andi Kleen wrote:
> From: Andi Kleen<ak@linux.intel.com>
>
> In fork and exit it's quite common to take same rmap chain locks
> again and again when the whole address space is processed for a
> address space that has a lot of sharing. Also since the locking
> has changed to always lock the root anon_vma this can be very
> contended.
>
> This patch adds a simple wrapper to batch these lock acquisitions
> and only reaquire the lock when another is needed. The main
> advantage is that when multiple processes are doing this in
> parallel they will avoid a lot of communication overhead
> on the lock cache line.
>
> I added a simple lock break (100 locks) for paranoia reason,
> but it's unclear if that's needed or not.
>
> Cc: Andrea Arcangeli<aarcange@redhat.com>
> Cc: Rik van Riel<riel@redhat.com>
> Signed-off-by: Andi Kleen<ak@linux.intel.com>
Reviewed-by: Rik van Riel<riel@redhat.com>
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next prev parent reply other threads:[~2011-05-06 16:00 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-05 19:32 Batch locking for rmap fork/exit processing Andi Kleen
2011-05-05 19:32 ` [PATCH 1/4] VM/RMAP: Add infrastructure for batching the rmap chain locking Andi Kleen
2011-05-06 15:59 ` Rik van Riel [this message]
2011-05-09 21:43 ` Andrew Morton
2011-05-09 22:23 ` Andi Kleen
2011-05-09 22:28 ` Andrew Morton
2011-05-09 23:02 ` Andi Kleen
2011-05-09 23:16 ` Andrew Morton
2011-05-10 0:05 ` Andi Kleen
2011-05-10 1:26 ` Andrew Morton
2011-05-10 1:27 ` Rik van Riel
2011-05-10 1:48 ` Andrew Morton
2011-05-05 19:32 ` [PATCH 2/4] VM/RMAP: Batch anon vma chain root locking in fork Andi Kleen
2011-05-06 15:59 ` Rik van Riel
2011-05-05 19:32 ` [PATCH 3/4] VM/RMAP: Batch anon_vma_unlink in exit Andi Kleen
2011-05-06 16:48 ` Rik van Riel
2011-05-05 19:32 ` [PATCH 4/4] VM/RMAP: Move avc freeing outside the lock Andi Kleen
2011-05-06 16:52 ` Rik van Riel
2011-05-06 16:44 ` Batch locking for rmap fork/exit processing Linus Torvalds
2011-05-06 17:05 ` Andi Kleen
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