Re: [PATCH] Repeated fork() causes SLAB to grow without bound

From: Rik van Riel
Date: Thu Nov 20 2014 - 09:50:32 EST


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On 11/20/2014 09:42 AM, Konstantin Khlebnikov wrote:

> I'm thinking about limitation for reusing anon_vmas which might
> increase performance without breaking asymptotic estimation of
> count anon_vma in the worst case. For example this heuristic: allow
> to reuse only anon_vma with single direct descendant. It seems
> there will be arount up to two times more anon_vmas but
> false-aliasing must be much lower.

It may even be possible to not create a child anon_vma for the
first child a parent forks, but only create a new anon_vma once
the parent clones a second child (alive at the same time as the
first child).

That still takes care of things like apache or sendmail, but
would not create infinite anon_vmas for a task that keeps forking
itself to infinite depth without calling exec...

- --
All rights reversed
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