On 08/06/20 8:12 pm, Sandipan Das wrote:
> The size of the cpu set 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 cpu set is dependent on the number
> of CPUs as reported by get_nprocs().
>
> Fixes: 3752e453f6ba ("selftests/powerpc: Add tests of PMU EBBs")
> Reported-by: Shirisha Ganta <shiga...@in.ibm.com>
> Signed-off-by: Sandipan Das <sandi...@linux.ibm.com>
> ---
> tools/testing/selftests/powerpc/utils.c | 33 ++++++++++++++++---------
> 1 file changed, 21 insertions(+), 12 deletions(-)
>
> diff --git a/tools/testing/selftests/powerpc/utils.c
> b/tools/testing/selftests/powerpc/utils.c
> index 933678f1ed0a..bb8e402752c0 100644
> --- a/tools/testing/selftests/powerpc/utils.c
> +++ b/tools/testing/selftests/powerpc/utils.c
> @@ -16,6 +16,7 @@
> [...]
>
> int pick_online_cpu(void)
> {
> - cpu_set_t mask;
> - int cpu;
> + int ncpus, cpu = -1;
> + cpu_set_t *mask;
> + size_t size;
>
> - CPU_ZERO(&mask);
> + ncpus = get_nprocs();
> + size = CPU_ALLOC_SIZE(ncpus);
> + mask = CPU_ALLOC(ncpus);
>
> - if (sched_getaffinity(0, sizeof(mask), &mask)) {
> + CPU_ZERO_S(size, 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;
Missed the fact that the for loop before this would anyway make 'cpu'
count down to -1 if no online CPU is found. Please ignore the previous
message.
> +
> +done:
> + CPU_FREE(mask);
> + return cpu;
> }
>
> bool is_ppc64le(void)
>
- Sandipan
