[ Upstream commit 1aa1dd9cc5 ]
charge_reserved_hugetlb.sh mounts a hugetlbfs instance at /mnt/huge with a
fixed size of 256M. On systems with large base hugepages (e.g. 512MB),
this is smaller than a single hugepage, so the hugetlbfs mount ends up
with zero capacity (often visible as size=0 in mount output).
As a result, write_to_hugetlbfs fails with ENOMEM and the test can hang
waiting for progress.
=== Error log ===
# uname -r
6.12.0-xxx.el10.aarch64+64k
#./charge_reserved_hugetlb.sh -cgroup-v2
# -----------------------------------------
...
# nr hugepages = 10
# writing cgroup limit: 5368709120
# writing reseravation limit: 5368709120
...
# write_to_hugetlbfs: Error mapping the file: Cannot allocate memory
# Waiting for hugetlb memory reservation to reach size 2684354560.
# 0
# Waiting for hugetlb memory reservation to reach size 2684354560.
# 0
...
# mount |grep /mnt/huge
none on /mnt/huge type hugetlbfs (rw,relatime,seclabel,pagesize=512M,size=0)
# grep -i huge /proc/meminfo
...
HugePages_Total: 10
HugePages_Free: 10
HugePages_Rsvd: 0
HugePages_Surp: 0
Hugepagesize: 524288 kB
Hugetlb: 5242880 kB
Drop the mount args with 'size=256M', so the filesystem capacity is sufficient
regardless of HugeTLB page size.
Link: https://lkml.kernel.org/r/20251221122639.3168038-3-liwang@redhat.com
Fixes: 29750f71a9 ("hugetlb_cgroup: add hugetlb_cgroup reservation tests")
Signed-off-by: Li Wang <liwang@redhat.com>
Acked-by: David Hildenbrand (Red Hat) <david@kernel.org>
Acked-by: Waiman Long <longman@redhat.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
122b02e61e