From: Chris Wright <chrisw@osdl.org>
To: Darren Hart <dvhltc@us.ibm.com>
Cc: Chris Wright <chrisw@osdl.org>,
hugh@veritas.com, akpm@osdl.org, andrea@suse.de,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] allow vma merging with mlock et. al.
Date: Fri, 25 Feb 2005 15:38:06 -0800 [thread overview]
Message-ID: <20050225233806.GD15867@shell0.pdx.osdl.net> (raw)
In-Reply-To: <421FA61B.9050705@us.ibm.com>
* Darren Hart (dvhltc@us.ibm.com) wrote:
> As I understand it, the reason we don't merge is because
> it is expected that a task will lock and unlock the same memory range
> more than once and we don't want to waste our time merging and splitting
> the VMAs.
I don't have a good sampling of applications. The one's I've used are
temporal like gpg, or they mlockall the whole thing and never look back.
But I did a quick benchmark since I was curious, a simple loop of a
million lock/unlock cycles of a page that could trigger a merge:
vanilla
(no merge): 659706 usecs
patched
(merge): 3567020 usecs
Heh, I was surprised to see it that much slower.
cheers,
-chris
--
Linux Security Modules http://lsm.immunix.org http://lsm.bkbits.net
next prev parent reply other threads:[~2005-02-25 23:39 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-02-25 0:43 [PATCH] vm: mlock superfluous variable Darren Hart
2005-02-25 17:11 ` Chris Wright
2005-02-25 22:05 ` [PATCH] allow vma merging with mlock et. al Chris Wright
2005-02-25 22:26 ` Darren Hart
2005-02-25 23:38 ` Chris Wright [this message]
2005-02-26 0:56 ` Andrea Arcangeli
2005-02-26 1:13 ` Chris Wright
2005-02-26 17:20 ` Hugh Dickins
2005-02-28 20:33 ` Chris Wright
2005-02-28 20:53 ` Hugh Dickins
2005-02-25 22:21 ` [PATCH] vm: mlock superfluous variable Darren Hart
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