Now, we have 'vcpu->guest_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 <[email protected]> --- include/linux/kvm_host.h | 6 ------ virt/kvm/kvm_main.c | 11 ++++------- 2 files changed, 4 insertions(+), 13 deletions(-) diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 5f5ef74..72b6dde 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -213,7 +213,6 @@ struct kvm_memslots { struct kvm { spinlock_t mmu_lock; - raw_spinlock_t requests_lock; struct mutex slots_lock; struct mm_struct *mm; /* userspace tied to this vm */ struct kvm_memslots *memslots; @@ -720,11 +719,6 @@ static inline void kvm_make_request(int req, struct kvm_vcpu *vcpu) set_bit(req, &vcpu->requests); } -static inline bool kvm_make_check_request(int req, struct kvm_vcpu *vcpu) -{ - return test_and_set_bit(req, &vcpu->requests); -} - static inline bool kvm_check_request(int req, struct kvm_vcpu *vcpu) { if (test_bit(req, &vcpu->requests)) { diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index a475264..1afcdcd 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -147,16 +147,14 @@ 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; - cpu = vcpu->cpu; + kvm_make_request(req, vcpu); /* Set ->requests bit before we read ->guest_mode */ smp_mb(); + cpu = vcpu->cpu; if (cpus != NULL && cpu != -1 && cpu != me && atomic_read(&vcpu->guest_mode)) cpumask_set_cpu(cpu, cpus); @@ -167,7 +165,7 @@ 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; } @@ -433,7 +431,6 @@ 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); -- 1.7.3.4 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
