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SubjectRe: [PATCH] allow vma merging with mlock et. al.
* 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
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