[PATCH 6/6] selftests/mm: Don't fail uffd-stress if too many CPUs

From: Brendan Jackman
Date: Thu Feb 20 2025 - 10:05:47 EST


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 | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/tools/testing/selftests/mm/uffd-stress.c b/tools/testing/selftests/mm/uffd-stress.c
index 1facfb79e09aa4113e344d7d90dec06a37264058..f306accbef255c79bc3eeba8b9e42161a88fc10e 100644
--- a/tools/testing/selftests/mm/uffd-stress.c
+++ b/tools/testing/selftests/mm/uffd-stress.c
@@ -453,6 +453,10 @@ int main(int argc, char **argv)
}

nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
+ if (nr_cpus > 32) {
+ /* Don't let calculation below go to zero. */
+ nr_cpus = 32;
+ }

nr_pages_per_cpu = bytes / page_size / nr_cpus;
if (!nr_pages_per_cpu) {

--
2.48.1.601.g30ceb7b040-goog