[PATCH 14/18] KVM: VMX: Avoid unnecessary vcpu_load()/vcpu_put() cycles

From: Avi Kivity
Date: Thu Apr 26 2007 - 05:25:24 EST


From: Eddie Dong <eddie.dong@xxxxxxxxx>

By checking if a reschedule is needed, we avoid dropping the vcpu.

[With changes by me, based on Anthony Liguori's observations]

Signed-off-by: Avi Kivity <avi@xxxxxxxxxxxx>
---
drivers/kvm/kvm_main.c | 2 ++
1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index 03c0ee7..f535635 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -1590,6 +1590,8 @@ static int set_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 data)

void kvm_resched(struct kvm_vcpu *vcpu)
{
+ if (!need_resched())
+ return;
vcpu_put(vcpu);
cond_resched();
vcpu_load(vcpu);
--
1.5.0.6

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/