[merged mm-stable] selftests-mm-scale-khugepageds-collapse-wait-with-the-pmd-size.patch removed from -mm tree

[Andrew Morton <akpm@linux-foundation.org>]

The quilt patch titled
     Subject: selftests/mm: scale khugepaged's collapse wait with the PMD size
has been removed from the -mm tree.  Its filename was
     selftests-mm-scale-khugepageds-collapse-wait-with-the-pmd-size.patch

This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: "Kiryl Shutsemau (Meta)" <kas@kernel.org>
Subject: selftests/mm: scale khugepaged's collapse wait with the PMD size
Date: Sat, 19 Sep 2026 01:24:33 +0100

wait_for_scan() gives every case the same three seconds, whatever the huge
page costs to build.  collapse_full() asks for four of them: 8M at a 2M
PMD, but 2G at a 512M PMD -- arm64 with 64K base pages.  Three seconds is
thin at that size, and the case has reported a failure for a collapse that
was still going.

The timeout is a ceiling on a poll loop, not a sleep: the loop stops as
soon as ops->check_huge() sees the collapse, or as soon as full_scans has
advanced by two.  Raising it costs a passing case nothing.  Across 80 runs
of collapse_full() on arm64 with 64K pages the wait was half a second in
73 of them, with a tail to two seconds.

Keep three seconds as the floor and add a second per 128M collapsed.  A 2M
PMD is unchanged, so x86-64 is too; a 512M PMD gets 19 seconds.

On arm64 with 64K pages a passing ./khugepaged all:anon takes 49 seconds
under TCG before and after this change.

Link: https://lore.kernel.org/20260919002451.496763-4-kirill@shutemov.name
Signed-off-by: Kiryl Shutsemau (Meta) <kas@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Tested-by: Muhammad Usama Anjum <usama.anjum@arm.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: Michal Hocko <mhocko@suse.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>
---

 tools/testing/selftests/mm/khugepaged.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

--- a/tools/testing/selftests/mm/khugepaged.c~selftests-mm-scale-khugepageds-collapse-wait-with-the-pmd-size
+++ a/tools/testing/selftests/mm/khugepaged.c
@@ -561,8 +561,11 @@ static bool wait_for_scan(const char *ms
 		int nr_hpages, int collap_order, struct mem_ops *ops)
 {
 	unsigned long hpage_size = page_size << collap_order;
-	int full_scans;
-	int timeout = 6; /* 3 seconds */
+	unsigned long bytes = (unsigned long)nr_hpages * hpage_size;
+	int timeout, full_scans;
+
+	/* Half-second ticks: three seconds floor, plus a second per 128M */
+	timeout = 6 + 2 * (bytes / (128UL << 20));
 
 	/* Sanity check */
 	if (!ops->check_huge(p, len, 0, hpage_size))
_

Patches currently in -mm which might be from kas@kernel.org are

mm-page_alloc-make-defrag_mode-retries-follow-the-promoted-order.patch
mm-khugepaged-drop-redundant-mm_struct-pin-in-madvise_collapse.patch
mm-khugepaged-count-collapses-where-khugepaged-makes-them.patch
mm-khugepaged-rename-mthp_present_ptes-bitmap-to-eligible_ptes.patch
mm-collapse-add-collapseh-for-the-collapse-interface.patch
mm-collapse-state-what-a-collapse-may-do-in-the-policy.patch
mm-collapse-drop-the-collapse_possible-wrapper.patch
mm-collapse-name-the-per-table-scan-reset-for-what-it-resets.patch
mm-collapse-call-collapse_file-from-collapse_single_pmd.patch
mm-collapse-separate-scanning-a-pte-table-from-collapsing-it.patch
mm-collapse-open-code-collapse_single_pmd-in-its-two-callers.patch
mm-collapse-work-out-the-orders-a-vma-allows-once-per-vma.patch
mm-collapse-declare-the-collapse-interface-in-collapseh.patch
mm-collapse-implement-madv_collapse-in-madvisec.patch