This calculation divides a fixed parameter by an environment-dependent
parameter i.e. the number of CPUs.
The simple way to avoid machine-specific failures here is to just put a
cap on the max value of the latter.
Suggested-by: Mateusz Guzik <mjguzik@xxxxxxxxx>
Signed-off-by: Brendan Jackman <jackmanb@xxxxxxxxxx>
---
tools/testing/selftests/mm/uffd-stress.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/mm/uffd-stress.c b/tools/testing/selftests/mm/uffd-stress.c
index 4ba5bf13a0108435ce8b53340b9e17ccd47e859e..40af7f67c4074d901be6608e5d64bd0490026dae 100644
--- a/tools/testing/selftests/mm/uffd-stress.c
+++ b/tools/testing/selftests/mm/uffd-stress.c
@@ -435,6 +435,7 @@ static void sigalrm(int sig)
int main(int argc, char **argv)
{
+ unsigned long nr_cpus;
size_t bytes;
if (argc < 4)
@@ -453,7 +454,15 @@ int main(int argc, char **argv)
return KSFT_SKIP;
}
- nr_parallel = sysconf(_SC_NPROCESSORS_ONLN);
+ nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
+ if (nr_cpus > 32) {
+ /* Don't let calculation below go to zero. */
+ ksft_print_msg("_SC_NPROCESSORS_ONLN (%lu) too large, capping nr_threads to 32\n",
+ nr_cpus);
+ nr_parallel = 32;
+ } else {
+ nr_parallel = nr_cpus;
+ }
nr_pages_per_cpu = bytes / page_size / nr_parallel;
if (!nr_pages_per_cpu) {
--
2.49.0.rc0.332.g42c0ae87b1-goog
