The patch titled
Subject: selftests/mm: don't fail uffd-stress if too many CPUs
has been added to the -mm mm-unstable branch. Its filename is
selftests-mm-dont-fail-uffd-stress-if-too-many-cpus.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/selftests-mm-dont-fail-uffd-stress-if-too-many-cpus.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Brendan Jackman <jackmanb@xxxxxxxxxx>
Subject: selftests/mm: don't fail uffd-stress if too many CPUs
Date: Fri, 21 Feb 2025 18:25:46 +0000
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.
Link: https://lkml.kernel.org/r/20250221-mm-selftests-v2-7-28c4d66383c5@xxxxxxxxxx
Signed-off-by: Brendan Jackman <jackmanb@xxxxxxxxxx>
Suggested-by: Mateusz Guzik <mjguzik@xxxxxxxxx>
Cc: Dev Jain <dev.jain@xxxxxxx>
Cc: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx>
Cc: Shuah Khan (Samsung OSG) <shuah@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
tools/testing/selftests/mm/uffd-stress.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
--- a/tools/testing/selftests/mm/uffd-stress.c~selftests-mm-dont-fail-uffd-stress-if-too-many-cpus
+++ a/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_threads = 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_threads = 32;
+ } else {
+ nr_cpus = nr_threads;
+ }
nr_pages_per_cpu = bytes / page_size / nr_threads;
if (!nr_pages_per_cpu) {
_
Patches currently in -mm which might be from jackmanb@xxxxxxxxxx are
mm-mmu_gather-update-comment-on-rcu-freeing.patch
selftests-mm-report-errno-when-things-fail-in-gup_longterm.patch
selftests-mm-fix-assumption-that-sudo-is-present.patch
selftests-mm-skip-uffd-stress-if-userfaultfd-not-available.patch
selftests-mm-skip-uffd-wp-mremap-if-userfaultfd-not-available.patch
selftests-mm-uffd-rename-nr_cpus-nr_threads.patch
selftests-mm-print-some-details-when-uffd-stress-gets-bad-params.patch
selftests-mm-dont-fail-uffd-stress-if-too-many-cpus.patch
selftests-mm-skip-map_populate-on-weird-filesystems.patch
selftests-mm-skip-gup_longerm-tests-on-weird-filesystems.patch
