selftests/mm: restore default nr_hugepages value via exit trap in charge_reserved_hugetlb.sh

Patch series "selftests/mm: fix failures and robustness improvements", v7.

Powerpc systems with a 64K base page size exposed several issues while
running mm selftests. Some tests assume specific hugetlb configurations,
use incorrect interfaces, or fail instead of skipping when the required
kernel features are not available.

This series fixes these issues and improves test robustness.


This patch (of 13):

cleanup() resets nr_hugepages to 0 on every invocation, while the test
reconfigures it again in the next iteration.  This leads to repeated
allocation and freeing of large numbers of hugepages, especially when the
original value is high.

Additionally, with set -e, failures in earlier cleanup steps (e.g., rmdir
or umount returning EBUSY while background activity is still ongoing) can
cause the script to exit before restoring the original value, leaving the
system in a modified state.

Introduce a trap on EXIT, INT, and TERM to restore the original
nr_hugepages value once at script termination.  This avoids unnecessary
allocation churn and ensures the original value is reliably restored on
all exit paths.

Link: https://lore.kernel.org/cover.1779296493.git.sayalip@linux.ibm.com
Link: https://lore.kernel.org/5b8fbb29cd6ceffe6752e0af104f60cec072aa10.1779296493.git.sayalip@linux.ibm.com
Fixes: 7d695b1c3695 ("selftests/mm: save and restore nr_hugepages value")
Signed-off-by: Sayali Patil <sayalip@linux.ibm.com>
Acked-by: Zi Yan <ziy@nvidia.com>
Tested-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

0 files changed, 0 insertions, 0 deletions