Re: [PATCH 0/4] KVM: srcu-less dirty logging

From: Peter Zijlstra
Date: Thu Feb 23 2012 - 08:25:45 EST


On Thu, 2012-02-23 at 20:33 +0900, Takuya Yoshikawa wrote:
> - Stop allocating extra dirty bitmap buffer area
>
> According to Peter, mmu_notifier has become preemptible. If we can
> change mmu_lock from spin_lock to mutex_lock, as Avi said before, this
> would be staightforward because we can use __put_user() right after
> xchg() with the mmu_lock held

So the 'only' thing to consider is running the end result with lockdep
enabled since the mmu locks are rather deep in the nesting tree its very
easy to accidentally cause inversions.


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