Re: missing madvise functionality

[Peter Zijlstra]

On Wed, 2007-04-04 at 12:22 +1000, Nick Piggin wrote:
> Eric Dumazet wrote:

> > I do think such workloads might benefit from a vma_cache not shared by 
> > all threads but private to each thread. A sequence could invalidate the 
> > cache(s).
> > 
> > ie instead of a mm->mmap_cache, having a mm->sequence, and each thread 
> > having a current->mmap_cache and current->mm_sequence
> 
> I have a patchset to do exactly this, btw.

/me too

However, I decided against pushing it because when it does happen that a
task is not involved with a vma lookup for longer than it takes the seq
count to wrap we have a stale pointer...

We could go and walk the tasks once in a while to reset the pointer, but
it all got a tad involved.

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