From: Avi Kivity <[email protected]> Usually the vcpu->requests bitmap is sparse, so a test_and_clear_bit() for each request generates a large number of unneeded atomics if a bit is set.
Replace with a separate test/clear sequence. This is safe since there is no clear_bit() outside the vcpu thread. Signed-off-by: Avi Kivity <[email protected]> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index c8a9d62..e820eb5 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -636,7 +636,12 @@ static inline bool kvm_make_check_request(int req, struct kvm_vcpu *vcpu) static inline bool kvm_check_request(int req, struct kvm_vcpu *vcpu) { - return test_and_clear_bit(req, &vcpu->requests); + if (test_bit(req, &vcpu->requests)) { + clear_bit(req, &vcpu->requests); + return true; + } else { + return false; + } } #endif -- To unsubscribe from this list: send the line "unsubscribe kvm-commits" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
