(2012/02/10 16:52), Xiao Guangrong wrote:
On 02/10/2012 02:28 PM, Takuya Yoshikawa wrote:
Other threads may process the same page in that small window and skip
TLB flush and then return before these functions do flush.
It is possible that flush tlb in mmu lock only when writeable
spte is invalided? Sometimes, kvm_flush_remote_tlbs need
long time to wait.
I am sorry but I don't see the point of adding yet another complexity
for that.
OK, let me clarify my position.
When I made this patch, I did a simple test to see if mmu notifier would
work normally after my patch applied: I allocated large memory behind
the guest and made the host call mmu_notifier functions.
In that situation the host as a whole became slow, e.g. I saw really bad
response for some seconds.
In such a case, do you mind the additional time VCPU threads may have to
wait until the mmu notifier finishes the flush, only when they are trying
to take the mmu_lock?
Takuya
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