diff options
Diffstat (limited to 'tools/testing/selftests/kvm/lib/perf_test_util.c')
| -rw-r--r-- | tools/testing/selftests/kvm/lib/perf_test_util.c | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/tools/testing/selftests/kvm/lib/perf_test_util.c b/tools/testing/selftests/kvm/lib/perf_test_util.c index d646477ed16a..722df3a28791 100644 --- a/tools/testing/selftests/kvm/lib/perf_test_util.c +++ b/tools/testing/selftests/kvm/lib/perf_test_util.c @@ -22,6 +22,9 @@ struct vcpu_thread { /* The pthread backing the vCPU. */ pthread_t thread; + + /* Set to true once the vCPU thread is up and running. */ + bool running; }; /* The vCPU threads involved in this test. */ @@ -30,6 +33,9 @@ static struct vcpu_thread vcpu_threads[KVM_MAX_VCPUS]; /* The function run by each vCPU thread, as provided by the test. */ static void (*vcpu_thread_fn)(struct perf_test_vcpu_args *); +/* Set to true once all vCPU threads are up and running. */ +static bool all_vcpu_threads_running; + /* * Continuously write to the first 8 bytes of each page in the * specified region. @@ -196,6 +202,17 @@ static void *vcpu_thread_main(void *data) { struct vcpu_thread *vcpu = data; + WRITE_ONCE(vcpu->running, true); + + /* + * Wait for all vCPU threads to be up and running before calling the test- + * provided vCPU thread function. This prevents thread creation (which + * requires taking the mmap_sem in write mode) from interfering with the + * guest faulting in its memory. + */ + while (!READ_ONCE(all_vcpu_threads_running)) + ; + vcpu_thread_fn(&perf_test_args.vcpu_args[vcpu->vcpu_id]); return NULL; @@ -206,14 +223,23 @@ void perf_test_start_vcpu_threads(int vcpus, void (*vcpu_fn)(struct perf_test_vc int vcpu_id; vcpu_thread_fn = vcpu_fn; + WRITE_ONCE(all_vcpu_threads_running, false); for (vcpu_id = 0; vcpu_id < vcpus; vcpu_id++) { struct vcpu_thread *vcpu = &vcpu_threads[vcpu_id]; vcpu->vcpu_id = vcpu_id; + WRITE_ONCE(vcpu->running, false); pthread_create(&vcpu->thread, NULL, vcpu_thread_main, vcpu); } + + for (vcpu_id = 0; vcpu_id < vcpus; vcpu_id++) { + while (!READ_ONCE(vcpu_threads[vcpu_id].running)) + ; + } + + WRITE_ONCE(all_vcpu_threads_running, true); } void perf_test_join_vcpu_threads(int vcpus) |