Re: [PATCH] KVM: Defer remote tlb flushes on invlpg (v4)

[Andrea Arcangeli <aarcange@redhat.com>]

On Sun, Apr 19, 2009 at 02:54:28PM -0300, Marcelo Tosatti wrote:
> I'm fine with your kvm_flush_local_tlb. Just one minor nit:
> 
> +   /* get new asid before returning to guest mode */
> +   if (!test_bit(KVM_REQ_TLB_FLUSH, &vcpu->requests))
> +               set_bit(KVM_REQ_TLB_FLUSH, &vcpu->requests);
> 
> Whats the test_bit for?

To avoid a write in case it was already set... but thinking twice I
guess the probability that it's already set is near zero, so I'll
remove it and I'll just do set_bit.

> It was nice to hide explicit knowledge about
> vcpu->kvm->remote_tlbs_dirty behind the interface instead of exposing
> it.

Hmm ok, if you prefer it I'll add it back. I guess ..._tlb_dirty_cond
is better name so it's clear it's not just checking the cond but the
dirty flag too.