selftests/mm: ensure uffd-wp-mremap gets pages of each size

This test allocates a page of every available size and doesn't have any
SKIP logic if the allocation fails.  So, ensure it's available and skip
the test if we can't do so.

Link: https://lkml.kernel.org/r/20250311-mm-selftests-v4-10-dec210a658f5@google.com
Signed-off-by: Brendan Jackman <jackmanb@google.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mateusz Guzik <mjguzik@gmail.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/tools/testing/selftests/mm/run_vmtests.sh b/tools/testing/selftests/mm/run_vmtests.sh
index 31a576d70b57265cf718ab41683c15fbda589e08..e1c20dcf8486d979b1232f9cf5399c1fa3e37d97 100755 (executable)
--- a/tools/testing/selftests/mm/run_vmtests.sh
+++ b/tools/testing/selftests/mm/run_vmtests.sh
@@ -325,9 +325,30 @@ CATEGORY="userfaultfd" run_test ${uffd_stress_bin} hugetlb "$half_ufd_size_MB" 3
 CATEGORY="userfaultfd" run_test ${uffd_stress_bin} hugetlb-private "$half_ufd_size_MB" 32
 CATEGORY="userfaultfd" run_test ${uffd_stress_bin} shmem 20 16
 CATEGORY="userfaultfd" run_test ${uffd_stress_bin} shmem-private 20 16
-CATEGORY="userfaultfd" run_test ./uffd-wp-mremap
+# uffd-wp-mremap requires at least one page of each size.
+have_all_size_hugepgs=true
+declare -A nr_size_hugepgs
+for f in /sys/kernel/mm/hugepages/**/nr_hugepages; do
+       old=$(cat $f)
+       nr_size_hugepgs["$f"]="$old"
+       if [ "$old" == 0 ]; then
+               echo 1 > "$f"
+       fi
+       if [ $(cat "$f") == 0 ]; then
+               have_all_size_hugepgs=false
+               break
+       fi
+done
+if $have_all_size_hugepgs; then
+       CATEGORY="userfaultfd" run_test ./uffd-wp-mremap
+else
+       echo "# SKIP ./uffd-wp-mremap"
+fi
 
 #cleanup
+for f in "${!nr_size_hugepgs[@]}"; do
+       echo "${nr_size_hugepgs["$f"]}" > "$f"
+done
 echo "$nr_hugepgs" > /proc/sys/vm/nr_hugepages
 
 CATEGORY="compaction" run_test ./compaction_test