diff options
| author | Longpeng(Mike) <longpeng2@huawei.com> | 2017-08-08 12:05:32 +0800 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2017-08-08 10:57:43 +0200 |
| commit | 199b5763d329b43c88f6ad539db8a6c6b42f8edb (patch) | |
| tree | 224f4ebeb9e58c43ea1916e63e813452f81dd45a /arch/s390 | |
| parent | 1b4d56b86a370a3785a33eba23e2e3009f5a03af (diff) | |
| download | linux-stable-199b5763d329b43c88f6ad539db8a6c6b42f8edb.tar.gz linux-stable-199b5763d329b43c88f6ad539db8a6c6b42f8edb.tar.bz2 linux-stable-199b5763d329b43c88f6ad539db8a6c6b42f8edb.zip | |
KVM: add spinlock optimization framework
If a vcpu exits due to request a user mode spinlock, then
the spinlock-holder may be preempted in user mode or kernel mode.
(Note that not all architectures trap spin loops in user mode,
only AMD x86 and ARM/ARM64 currently do).
But if a vcpu exits in kernel mode, then the holder must be
preempted in kernel mode, so we should choose a vcpu in kernel mode
as a more likely candidate for the lock holder.
This introduces kvm_arch_vcpu_in_kernel() to decide whether the
vcpu is in kernel-mode when it's preempted. kvm_vcpu_on_spin's
new argument says the same of the spinning VCPU.
Signed-off-by: Longpeng(Mike) <longpeng2@huawei.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/s390')
| -rw-r--r-- | arch/s390/kvm/diag.c | 2 | ||||
| -rw-r--r-- | arch/s390/kvm/kvm-s390.c | 5 |
2 files changed, 6 insertions, 1 deletions
diff --git a/arch/s390/kvm/diag.c b/arch/s390/kvm/diag.c index ce865bd4f81d..6182edebea3d 100644 --- a/arch/s390/kvm/diag.c +++ b/arch/s390/kvm/diag.c @@ -150,7 +150,7 @@ static int __diag_time_slice_end(struct kvm_vcpu *vcpu) { VCPU_EVENT(vcpu, 5, "%s", "diag time slice end"); vcpu->stat.diagnose_44++; - kvm_vcpu_on_spin(vcpu); + kvm_vcpu_on_spin(vcpu, false); return 0; } diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index af09d3437631..5e07322034b9 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -2447,6 +2447,11 @@ int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu) return kvm_s390_vcpu_has_irq(vcpu, 0); } +bool kvm_arch_vcpu_in_kernel(struct kvm_vcpu *vcpu) +{ + return false; +} + void kvm_s390_vcpu_block(struct kvm_vcpu *vcpu) { atomic_or(PROG_BLOCK_SIE, &vcpu->arch.sie_block->prog20); |