Messages in this thread | | | From | Paolo Bonzini <> | Subject | Re: [PATCH 15/24] kvm: mmu: Wrap mmu_lock cond_resched and needbreak | Date | Tue, 26 Jan 2021 15:38:09 +0100 |
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On 21/01/21 01:19, Sean Christopherson wrote: > What if we simply make the common mmu_lock a union? The rwlock_t is > probably a bit bigger, but that's a few bytes for an entire VM. And > maybe this would entice/inspire other architectures to move to a similar > MMU model.
Looking more at this, there is a problem in that MMU notifier functions take the MMU lock.
Yes, qrwlock the size is a bit larger than qspinlock. However, the fast path of qrwlocks is small, and if the slow paths are tiny compared to the mmu_lock critical sections that are so big as to require cond_resched. So I would consider just changing all architectures to an rwlock.
Paolo
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