From c2a811630880eec62025b9975d5ce09e891f152f Mon Sep 17 00:00:00 2001 From: Harish Date: Tue, 9 Jun 2020 13:44:23 +0530 Subject: selftests/powerpc: Fix CPU affinity for child process [ Upstream commit 854eb5022be04f81e318765f089f41a57c8e5d83 ] On systems with large number of cpus, test fails trying to set affinity by calling sched_setaffinity() with smaller size for affinity mask. This patch fixes it by making sure that the size of allocated affinity mask is dependent on the number of CPUs as reported by get_nprocs(). Fixes: 00b7ec5c9cf3 ("selftests/powerpc: Import Anton's context_switch2 benchmark") Reported-by: Shirisha Ganta Signed-off-by: Sandipan Das Signed-off-by: Harish Reviewed-by: Kamalesh Babulal Reviewed-by: Satheesh Rajendran Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200609081423.529664-1-harish@linux.ibm.com Signed-off-by: Sasha Levin --- .../selftests/powerpc/benchmarks/context_switch.c | 21 ++++++++++++++++----- 1 file changed, 16 insertions(+), 5 deletions(-) (limited to 'tools') diff --git a/tools/testing/selftests/powerpc/benchmarks/context_switch.c b/tools/testing/selftests/powerpc/benchmarks/context_switch.c index 87f1f0252299..9ec7674697b1 100644 --- a/tools/testing/selftests/powerpc/benchmarks/context_switch.c +++ b/tools/testing/selftests/powerpc/benchmarks/context_switch.c @@ -23,6 +23,7 @@ #include #include #include +#include #include #include #include @@ -108,8 +109,9 @@ static void start_thread_on(void *(*fn)(void *), void *arg, unsigned long cpu) static void start_process_on(void *(*fn)(void *), void *arg, unsigned long cpu) { - int pid; - cpu_set_t cpuset; + int pid, ncpus; + cpu_set_t *cpuset; + size_t size; pid = fork(); if (pid == -1) { @@ -120,14 +122,23 @@ static void start_process_on(void *(*fn)(void *), void *arg, unsigned long cpu) if (pid) return; - CPU_ZERO(&cpuset); - CPU_SET(cpu, &cpuset); + ncpus = get_nprocs(); + size = CPU_ALLOC_SIZE(ncpus); + cpuset = CPU_ALLOC(ncpus); + if (!cpuset) { + perror("malloc"); + exit(1); + } + CPU_ZERO_S(size, cpuset); + CPU_SET_S(cpu, size, cpuset); - if (sched_setaffinity(0, sizeof(cpuset), &cpuset)) { + if (sched_setaffinity(0, size, cpuset)) { perror("sched_setaffinity"); + CPU_FREE(cpuset); exit(1); } + CPU_FREE(cpuset); fn(arg); exit(0); -- cgit v1.2.3