From: Sandipan Das sandipan@linux.ibm.com
[ Upstream commit dfa03fff86027e58c8dba5c03ae68150d4e513ad ]
The size of the CPU affinity mask must be large enough for systems with a very large number of CPUs. Otherwise, tests which try to determine the first online CPU by calling sched_getaffinity() will fail. This makes sure that the size of the allocated affinity mask is dependent on the number of CPUs as reported by get_nprocs_conf().
Fixes: 3752e453f6ba ("selftests/powerpc: Add tests of PMU EBBs") Reported-by: Shirisha Ganta shiganta@in.ibm.com Signed-off-by: Sandipan Das sandipan@linux.ibm.com Reviewed-by: Kamalesh Babulal kamalesh@linux.vnet.ibm.com Signed-off-by: Michael Ellerman mpe@ellerman.id.au Link: https://lore.kernel.org/r/a408c4b8e9a23bb39b539417a21eb0ff47bb5127.159608485... Signed-off-by: Sasha Levin sashal@kernel.org --- tools/testing/selftests/powerpc/utils.c | 37 +++++++++++++++++-------- 1 file changed, 25 insertions(+), 12 deletions(-)
diff --git a/tools/testing/selftests/powerpc/utils.c b/tools/testing/selftests/powerpc/utils.c index dcf74184bfd0a..bafb70d0ee264 100644 --- a/tools/testing/selftests/powerpc/utils.c +++ b/tools/testing/selftests/powerpc/utils.c @@ -12,6 +12,7 @@ #include <sched.h> #include <stdio.h> #include <sys/stat.h> +#include <sys/sysinfo.h> #include <sys/types.h> #include <unistd.h>
@@ -62,26 +63,38 @@ void *get_auxv_entry(int type)
int pick_online_cpu(void) { - cpu_set_t mask; - int cpu; + int ncpus, cpu = -1; + cpu_set_t *mask; + size_t size; + + ncpus = get_nprocs_conf(); + size = CPU_ALLOC_SIZE(ncpus); + mask = CPU_ALLOC(ncpus); + if (!mask) { + perror("malloc"); + return -1; + }
- CPU_ZERO(&mask); + CPU_ZERO_S(size, mask);
- if (sched_getaffinity(0, sizeof(mask), &mask)) { + if (sched_getaffinity(0, size, mask)) { perror("sched_getaffinity"); - return -1; + goto done; }
/* We prefer a primary thread, but skip 0 */ - for (cpu = 8; cpu < CPU_SETSIZE; cpu += 8) - if (CPU_ISSET(cpu, &mask)) - return cpu; + for (cpu = 8; cpu < ncpus; cpu += 8) + if (CPU_ISSET_S(cpu, size, mask)) + goto done;
/* Search for anything, but in reverse */ - for (cpu = CPU_SETSIZE - 1; cpu >= 0; cpu--) - if (CPU_ISSET(cpu, &mask)) - return cpu; + for (cpu = ncpus - 1; cpu >= 0; cpu--) + if (CPU_ISSET_S(cpu, size, mask)) + goto done;
printf("No cpus in affinity mask?!\n"); - return -1; + +done: + CPU_FREE(mask); + return cpu; }