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| author |   Christian Borntraeger <borntraeger@de.ibm.com> | 2014-08-19 16:45:56 +0200 |
|---|---|---|
| committer |   Paolo Bonzini <pbonzini@redhat.com> | 2014-08-21 13:50:22 +0200 |
| commit | 7103f60de8bed21a0ad5d15d2ad5b7a333dda201 (patch) | |
| tree | 3f78e7d4a4e03ec6c81616239bad7a2dde205cf0 /virt | |
| parent | KVM: emulate: warn on invalid or uninitialized exception numbers (diff) | |
| download | linux-dev-7103f60de8bed21a0ad5d15d2ad5b7a333dda201.tar.xz linux-dev-7103f60de8bed21a0ad5d15d2ad5b7a333dda201.zip | |
KVM: avoid unnecessary synchronize_rcu
We dont have to wait for a grace period if there is no oldpid that
we are going to free. putpid also checks for NULL, so this patch
only fences synchronize_rcu.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'virt')
| -rw-r--r-- | virt/kvm/kvm_main.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 33712fb26eb1..39b16035386f 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -129,7 +129,8 @@ int vcpu_load(struct kvm_vcpu *vcpu) struct pid *oldpid = vcpu->pid; struct pid *newpid = get_task_pid(current, PIDTYPE_PID); rcu_assign_pointer(vcpu->pid, newpid); - synchronize_rcu(); + if (oldpid) + synchronize_rcu(); put_pid(oldpid); } cpu = get_cpu(); |