selftests/mm: stop khugepaged during the MADV_COLLAPSE cases

__madvise_collapse() turns THP off before each MADV_COLLAPSE, both to keep
khugepaged out of the range and to prove MADV_COLLAPSE ignores the
setting.  It clears the global controls only, which is no longer enough. 
A per-order control overrides them, and -s, which makes the cases fault in
folios of one order, leaves that order's control at "always".  khugepaged
then collapses the very range the case is working on, and the case fails
on a collapse that was interfered with rather than refused.

Clear the per-order controls too.  MADV_COLLAPSE does not consult them:
anon never did, and shmem stopped with "mm: shmem: ignore sysfs configs
for shmem forced collapse".

Link: https://lore.kernel.org/20260919002451.496763-7-kirill@shutemov.name
Fixes: b7f16963efe7 ("mm/khugepaged: run khugepaged for all orders")
Signed-off-by: Kiryl Shutsemau (Meta) <kas@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Assisted-by: LLM
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Barry Song <baohua@kernel.org>
Cc: "David Hildenbrand (arm)" <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Hugh Dickens <hughd@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: kernel-team@meta.com
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Muhammad Usama Anjum <usama.anjum@arm.com>
Cc: Nico Pache (Red Hat) <nico.pache@linux.dev>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan (Samsung OSG) <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Usama Arif <usama.arif@linux.dev>
Cc: "Vlastimil Babka (SUSE)" <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>

1 files changed, 5 insertions, 1 deletions

diff --git a/tools/testing/selftests/mm/khugepaged.c b/tools/testing/selftests/mm/khugepaged.c
index 13a2a47ab110..e013eebc7136 100644
--- a/tools/testing/selftests/mm/khugepaged.c
+++ b/tools/testing/selftests/mm/khugepaged.c
@@ -538,8 +538,8 @@ static bool is_anon(struct mem_ops *ops)
 static void __madvise_collapse(const char *msg, char *p, int nr_hpages,
 			       struct mem_ops *ops, bool expect)
 {
-	int ret;
 	struct thp_settings settings = *thp_current_settings();
+	int ret, i;
 
 	ksft_print_msg("%s...", msg);
 
@@ -555,6 +555,10 @@ static void __madvise_collapse(const char *msg, char *p, int nr_hpages,
 	 */
 	settings.thp_enabled = THP_NEVER;
 	settings.shmem_enabled = SHMEM_NEVER;
+	for (i = 0; i < NR_ORDERS; i++) {
+		settings.hugepages[i].enabled = THP_NEVER;
+		settings.shmem_hugepages[i].enabled = SHMEM_NEVER;
+	}
 	thp_push_settings(&settings);
 
 	/* Clear VM_NOHUGEPAGE */