diff options
| author |   Sean Christopherson <seanjc@google.com> | 2021-10-08 19:11:59 -0700 |
|---|---|---|
| committer |   Paolo Bonzini <pbonzini@redhat.com> | 2021-12-08 04:24:47 -0500 |
| commit | 29e72893cec3b0268e19e7857d10bf79843f94dc (patch) | |
| tree | c2fe06dba28b79d71a52ab8861b9645a67721878 /virt | |
| parent | KVM: Update halt-polling stats if and only if halt-polling was attempted (diff) | |
| download | linux-dev-29e72893cec3b0268e19e7857d10bf79843f94dc.tar.xz linux-dev-29e72893cec3b0268e19e7857d10bf79843f94dc.zip | |
KVM: Refactor and document halt-polling stats update helper
Add a comment to document that halt-polling is considered successful even
if the polling loop itself didn't detect a wake event, i.e. if a wake
event was detect in the final kvm_vcpu_check_block(). Invert the param
to update helper so that the helper is a dumb function that is "told"
whether or not polling was successful, as opposed to determining success
based on blocking behavior.
Opportunistically tweak the params to the update helper to reduce the
line length for the call site so that it fits on a single line, and so
that the prototype conforms to the more traditional kernel style.
No functional change intended.
Reviewed-by: David Matlack <dmatlack@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20211009021236.4122790-7-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'virt')
| -rw-r--r-- | virt/kvm/kvm_main.c | 20 |
1 files changed, 13 insertions, 7 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 1a15043ceecb..a7f9c313d642 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -3272,13 +3272,15 @@ out: return ret; } -static inline void -update_halt_poll_stats(struct kvm_vcpu *vcpu, u64 poll_ns, bool waited) +static inline void update_halt_poll_stats(struct kvm_vcpu *vcpu, ktime_t start, + ktime_t end, bool success) { - if (waited) - vcpu->stat.generic.halt_poll_fail_ns += poll_ns; - else + u64 poll_ns = ktime_to_ns(ktime_sub(end, start)); + + if (success) vcpu->stat.generic.halt_poll_success_ns += poll_ns; + else + vcpu->stat.generic.halt_poll_fail_ns += poll_ns; } /* @@ -3348,9 +3350,13 @@ out: kvm_arch_vcpu_unblocking(vcpu); block_ns = ktime_to_ns(cur) - ktime_to_ns(start); + /* + * Note, halt-polling is considered successful so long as the vCPU was + * never actually scheduled out, i.e. even if the wake event arrived + * after of the halt-polling loop itself, but before the full wait. + */ if (do_halt_poll) - update_halt_poll_stats( - vcpu, ktime_to_ns(ktime_sub(poll_end, start)), waited); + update_halt_poll_stats(vcpu, start, poll_end, !waited); if (halt_poll_allowed) { if (!vcpu_valid_wakeup(vcpu)) { |