Hi,
In workload with heavy page reclaim, flush_tlb_page() is frequently
used. We currently have 8 vectors for tlb flush, which is fine for small
machines. But for big machines with a lot of CPUs, the 8 vectors are
shared by all CPUs and we need lock to protect them. This will cause a
lot of lock contentions. please see the patch 3 for detailed number of
the lock contention.
Andi Kleen suggests we can use 32 vectors for tlb flush, which should be
fine for even 8 socket machines. Test shows this reduces lock contention
dramatically (see patch 3 for number).
One might argue if this will waste too many vectors and leave less
vectors for devices. This could be a problem. But even we use 32
vectors, we still leave 78 vectors for devices. And we now have per-cpu
vector, vector isn't scarce any more, but I'm open if anybody has
objections.

Thanks,
Shaohua

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Hi Ingo & hpa, any comments about this series?

Thanks,
Shaohua

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Hi Shaohua,

It looks good... I need to do a more thorough review and put it in; I
just have been consumed a bit too much by a certain internal project.

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.

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