提交 58d2930f 编写于 作者: T Takuya Yoshikawa 提交者: Marcelo Tosatti

KVM: Eliminate extra function calls in kvm_get_dirty_log_protect()

When all bits in mask are not set,
kvm_arch_mmu_enable_log_dirty_pt_masked() has nothing to do.  But since
it needs to be called from the generic code, it cannot be inlined, and
a few function calls, two when PML is enabled, are wasted.

Since it is common to see many pages remain clean, e.g. framebuffers can
stay calm for a long time, it is worth eliminating this overhead.
Signed-off-by: NTakuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>
上级 faac2458
......@@ -1053,9 +1053,11 @@ int kvm_get_dirty_log_protect(struct kvm *kvm,
mask = xchg(&dirty_bitmap[i], 0);
dirty_bitmap_buffer[i] = mask;
offset = i * BITS_PER_LONG;
kvm_arch_mmu_enable_log_dirty_pt_masked(kvm, memslot, offset,
mask);
if (mask) {
offset = i * BITS_PER_LONG;
kvm_arch_mmu_enable_log_dirty_pt_masked(kvm, memslot,
offset, mask);
}
}
spin_unlock(&kvm->mmu_lock);
......
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