diff options
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/testing/selftests/kvm/rseq_test.c | 69 |
1 files changed, 59 insertions, 10 deletions
diff --git a/tools/testing/selftests/kvm/rseq_test.c b/tools/testing/selftests/kvm/rseq_test.c index c5e0dd664a7b..4158da0da2bb 100644 --- a/tools/testing/selftests/kvm/rseq_test.c +++ b/tools/testing/selftests/kvm/rseq_test.c @@ -10,6 +10,7 @@ #include <signal.h> #include <syscall.h> #include <sys/ioctl.h> +#include <sys/sysinfo.h> #include <asm/barrier.h> #include <linux/atomic.h> #include <linux/rseq.h> @@ -39,6 +40,7 @@ static __thread volatile struct rseq __rseq = { static pthread_t migration_thread; static cpu_set_t possible_mask; +static int min_cpu, max_cpu; static bool done; static atomic_t seq_cnt; @@ -57,20 +59,37 @@ static void sys_rseq(int flags) TEST_ASSERT(!r, "rseq failed, errno = %d (%s)", errno, strerror(errno)); } +static int next_cpu(int cpu) +{ + /* + * Advance to the next CPU, skipping those that weren't in the original + * affinity set. Sadly, there is no CPU_SET_FOR_EACH, and cpu_set_t's + * data storage is considered as opaque. Note, if this task is pinned + * to a small set of discontigous CPUs, e.g. 2 and 1023, this loop will + * burn a lot cycles and the test will take longer than normal to + * complete. + */ + do { + cpu++; + if (cpu > max_cpu) { + cpu = min_cpu; + TEST_ASSERT(CPU_ISSET(cpu, &possible_mask), + "Min CPU = %d must always be usable", cpu); + break; + } + } while (!CPU_ISSET(cpu, &possible_mask)); + + return cpu; +} + static void *migration_worker(void *ign) { cpu_set_t allowed_mask; - int r, i, nr_cpus, cpu; + int r, i, cpu; CPU_ZERO(&allowed_mask); - nr_cpus = CPU_COUNT(&possible_mask); - - for (i = 0; i < NR_TASK_MIGRATIONS; i++) { - cpu = i % nr_cpus; - if (!CPU_ISSET(cpu, &possible_mask)) - continue; - + for (i = 0, cpu = min_cpu; i < NR_TASK_MIGRATIONS; i++, cpu = next_cpu(cpu)) { CPU_SET(cpu, &allowed_mask); /* @@ -154,6 +173,36 @@ static void *migration_worker(void *ign) return NULL; } +static int calc_min_max_cpu(void) +{ + int i, cnt, nproc; + + if (CPU_COUNT(&possible_mask) < 2) + return -EINVAL; + + /* + * CPU_SET doesn't provide a FOR_EACH helper, get the min/max CPU that + * this task is affined to in order to reduce the time spent querying + * unusable CPUs, e.g. if this task is pinned to a small percentage of + * total CPUs. + */ + nproc = get_nprocs_conf(); + min_cpu = -1; + max_cpu = -1; + cnt = 0; + + for (i = 0; i < nproc; i++) { + if (!CPU_ISSET(i, &possible_mask)) + continue; + if (min_cpu == -1) + min_cpu = i; + max_cpu = i; + cnt++; + } + + return (cnt < 2) ? -EINVAL : 0; +} + int main(int argc, char *argv[]) { int r, i, snapshot; @@ -167,8 +216,8 @@ int main(int argc, char *argv[]) TEST_ASSERT(!r, "sched_getaffinity failed, errno = %d (%s)", errno, strerror(errno)); - if (CPU_COUNT(&possible_mask) < 2) { - print_skip("Only one CPU, task migration not possible\n"); + if (calc_min_max_cpu()) { + print_skip("Only one usable CPU, task migration not possible"); exit(KSFT_SKIP); } |