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authorXiao Guangrong <xiaoguangrong@cn.fujitsu.com>2011-01-12 15:41:22 +0800
committerMarcelo Tosatti <mtosatti@redhat.com>2011-03-17 13:08:26 -0300
commit3cba41307a2b1344ab8c1b9f55202d1e9d7bf81b (patch)
tree87191d63557cc722906ceaec98a1f8f148cf1fcc /virt/kvm/kvm_main.c
parent6b7e2d0991489559a1df4500d77f7b76c4607ed0 (diff)
downloadlinaro-lsk-3cba41307a2b1344ab8c1b9f55202d1e9d7bf81b.tar.gz
KVM: make make_all_cpus_request() lockless
Now, we have 'vcpu->mode' to judge whether need to send ipi to other cpus, this way is very exact, so checking request bit is needless, then we can drop the spinlock let it's collateral Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'virt/kvm/kvm_main.c')
-rw-r--r--virt/kvm/kvm_main.c9
1 files changed, 3 insertions, 6 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 19209f849cf..4856a7dcbd7 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -165,11 +165,9 @@ static bool make_all_cpus_request(struct kvm *kvm, unsigned int req)
zalloc_cpumask_var(&cpus, GFP_ATOMIC);
- raw_spin_lock(&kvm->requests_lock);
- me = smp_processor_id();
+ me = get_cpu();
kvm_for_each_vcpu(i, vcpu, kvm) {
- if (kvm_make_check_request(req, vcpu))
- continue;
+ kvm_make_request(req, vcpu);
cpu = vcpu->cpu;
/* Set ->requests bit before we read ->mode */
@@ -185,7 +183,7 @@ static bool make_all_cpus_request(struct kvm *kvm, unsigned int req)
smp_call_function_many(cpus, ack_flush, NULL, 1);
else
called = false;
- raw_spin_unlock(&kvm->requests_lock);
+ put_cpu();
free_cpumask_var(cpus);
return called;
}
@@ -468,7 +466,6 @@ static struct kvm *kvm_create_vm(void)
kvm->mm = current->mm;
atomic_inc(&kvm->mm->mm_count);
spin_lock_init(&kvm->mmu_lock);
- raw_spin_lock_init(&kvm->requests_lock);
kvm_eventfd_init(kvm);
mutex_init(&kvm->lock);
mutex_init(&kvm->irq_lock);