Eric Lee / smarc-fsl-linux-kernel

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Commit 3cba41307a2b1344ab8c1b9f55202d1e9d7bf81b

Authored by Xiao Guangrong
Committed by Marcelo Tosatti
1 parent 6b7e2d0991
Exists in master and in 39 other branches 8mp-imx_5.4.70_2.3.0, 8qm-imx_5.4.70_2.3.0, emb_imx_lf-5.15.y, emb_lf-6.1.y, imx_3.0.35_4.1.0, imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, imx_4.1.15_1.0.0_ga, pitx_8mp_lf-5.10.y, rt-smarc-imx_4.1.15_1.0.0_ga, rt_linux_5.15.71, smarc-8m-android-11.0.0_2.0.0, smarc-imx6_4.14.98_2.0.0_ga, smarc-imx6_4.9.88_2.0.0_ga, smarc-imx7_4.14.98_2.0.0_ga, smarc-imx7_4.9.11_1.0.0_ga, smarc-imx7_4.9.88_2.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga, smarc-imx_4.1.15_1.0.0_ga, smarc-imx_4.9.11_1.0.0_ga, smarc-imx_4.9.51_imx8m_ga, smarc-imx_4.9.88_2.0.0_ga, smarc-m6.0.1_2.1.0-ga, smarc-n7.1.2_2.0.0-ga, smarc-rel_imx_4.1.15_1.2.0_ga, smarc_8m_00d0_imx_4.14.98_2.0.0_ga, smarc_8m_imx_4.14.78_1.0.0_ga, smarc_8m_imx_4.14.98_2.0.0_ga, smarc_8m_imx_4.19.35_1.1.0, smarc_8mm_imx_4.14.78_1.0.0_ga, smarc_8mm_imx_4.14.98_2.0.0_ga, smarc_8mm_imx_4.19.35_1.1.0, smarc_8mm_imx_5.4.24_2.1.0, smarc_8mp_lf-5.10.y, smarc_8mq_imx_5.4.24_2.1.0, smarc_8mq_lf-5.10.y, smarc_imx_lf-5.15.y

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>

Showing 2 changed files with 3 additions and 12 deletions Side-by-side Diff

include/linux/kvm_host.h
Diff comments   View file @ 3cba413
... ... @@ -224,7 +224,6 @@
224 224  
225 225 struct kvm {
226 226 spinlock_t mmu_lock;
227   - raw_spinlock_t requests_lock;
228 227 struct mutex slots_lock;
229 228 struct mm_struct *mm; /* userspace tied to this vm */
230 229 struct kvm_memslots *memslots;
... ... @@ -729,11 +728,6 @@
729 728 static inline void kvm_make_request(int req, struct kvm_vcpu *vcpu)
730 729 {
731 730 set_bit(req, &vcpu->requests);
732   -}
733   -
734   -static inline bool kvm_make_check_request(int req, struct kvm_vcpu *vcpu)
735   -{
736   - return test_and_set_bit(req, &vcpu->requests);
737 731 }
738 732  
739 733 static inline bool kvm_check_request(int req, struct kvm_vcpu *vcpu)
... ... @@ -165,11 +165,9 @@
165 165  
166 166 zalloc_cpumask_var(&cpus, GFP_ATOMIC);
167 167  
168   - raw_spin_lock(&kvm->requests_lock);
169   - me = smp_processor_id();
  168 + me = get_cpu();
170 169 kvm_for_each_vcpu(i, vcpu, kvm) {
171   - if (kvm_make_check_request(req, vcpu))
172   - continue;
  170 + kvm_make_request(req, vcpu);
173 171 cpu = vcpu->cpu;
174 172  
175 173 /* Set ->requests bit before we read ->mode */
... ... @@ -185,7 +183,7 @@
185 183 smp_call_function_many(cpus, ack_flush, NULL, 1);
186 184 else
187 185 called = false;
188   - raw_spin_unlock(&kvm->requests_lock);
  186 + put_cpu();
189 187 free_cpumask_var(cpus);
190 188 return called;
191 189 }
... ... @@ -468,7 +466,6 @@
468 466 kvm->mm = current->mm;
469 467 atomic_inc(&kvm->mm->mm_count);
470 468 spin_lock_init(&kvm->mmu_lock);
471   - raw_spin_lock_init(&kvm->requests_lock);
472 469 kvm_eventfd_init(kvm);
473 470 mutex_init(&kvm->lock);
474 471 mutex_init(&kvm->irq_lock);