[merged mm-stable] selftests-mm-run-every-supported-collapse-order-by-default.patch removed from -mm tree

[merged mm-stable] selftests-mm-run-every-supported-collapse-order-by-default.patch removed from -mm tree

[Andrew Morton]

The quilt patch titled
     Subject: selftests/mm: run every supported collapse order by default
has been removed from the -mm tree.  Its filename was
     selftests-mm-run-every-supported-collapse-order-by-default.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: run every supported collapse order by default
Date: Sat, 19 Sep 2026 01:24:44 +0100

The mTHP collapse cases only run when the caller names both the context
and an order, so a plain ./khugepaged covers the PMD contexts on anon and
nothing else.  run_vmtests.sh pinned order 4 and covered no other.

Run the mTHP cases once per supported anon THP order below the PMD when -c
is absent, and pull that context into both the no-argument invocation and
"all".  Also:

  - -c still pins one order, and now says what is wrong instead of
    printing the usage text.

  - Both orders end up as array indices and shift counts, so -s and -c
    are range-checked before they get there.

  - The mTHP context has only anon cases, so a run that names a different
    mem_type -- "all:shmem", say -- drops it again rather than refusing
    to start.  Naming both explicitly still refuses.

  - A case carries the order it was registered at, so a result names it:

      # Run test: collapse_single_mthp (mthp_khugepaged:anon, order 6)

On x86-64 with 4K pages that is orders 2 through 8, and ./khugepaged goes
from 29 results in 17 seconds to 77 in 29, so run_vmtests.sh can drop its
pinned order-4 line.

Link: https://lore.kernel.org/20260919002451.496763-15-kirill@shutemov.name
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>
Tested-by: Muhammad Usama Anjum <usama.anjum@arm.com>
Tested-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: 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   |  101 +++++++++++++++-----
 tools/testing/selftests/mm/run_vmtests.sh |    2 
 2 files changed, 78 insertions(+), 25 deletions(-)

--- a/tools/testing/selftests/mm/khugepaged.c~selftests-mm-run-every-supported-collapse-order-by-default
+++ a/tools/testing/selftests/mm/khugepaged.c
@@ -30,6 +30,9 @@ static unsigned long page_size;
 static int hpage_pmd_nr;
 static int anon_order;
 static int collapse_order;
+static bool collapse_order_set;
+static int collapse_orders[NR_ORDERS];
+static int nr_collapse_orders;
 static int pagemap_fd = -1;
 static int kpageflags_fd = -1;
 
@@ -1525,12 +1528,14 @@ static void usage(void)
 	fprintf(stderr,	"\t\t-s: mTHP size, expressed as page order.\n");
 	fprintf(stderr,	"\t\t    Defaults to 0. Use this size for anon or shmem allocations.\n");
 	fprintf(stderr,	"\t\t-c: collapse order for mTHP collapse, expressed as page order.\n");
+	fprintf(stderr,	"\t\t    Defaults to every supported order below the PMD.\n");
 	fprintf(stderr,	"\t\t    -s, if set, is the source order for the mixed-source case.\n");
 	exit(1);
 }
 
 static void parse_test_type(int argc, char **argv)
 {
+	bool mthp_context_implied = false;
 	int opt;
 	char *buf;
 	const char *token;
@@ -1542,6 +1547,7 @@ static void parse_test_type(int argc, ch
 			break;
 		case 'c':
 			collapse_order = atoi(optarg);
+			collapse_order_set = true;
 			break;
 		case 'h':
 		default:
@@ -1549,12 +1555,25 @@ static void parse_test_type(int argc, ch
 		}
 	}
 
+	/*
+	 * Both orders end up as array indices and shift counts, so neither
+	 * can be negative, and a zero collapse order asks for base pages.
+	 */
+	if (anon_order < 0 || anon_order > hpage_pmd_order)
+		ksft_exit_fail_msg("-s takes an order in 0..%d, not %d\n",
+				   hpage_pmd_order, anon_order);
+	if (collapse_order_set &&
+	    (collapse_order <= 0 || collapse_order >= hpage_pmd_order))
+		ksft_exit_fail_msg("-c takes an order in 1..%d, not %d\n",
+				   hpage_pmd_order - 1, collapse_order);
+
 	argv += optind;
 	argc -= optind;
 
 	if (argc == 0) {
-		/* Backwards compatibility */
+		/* No arguments: anon under every context */
 		khugepaged_context =  &__khugepaged_context;
+		mthp_khugepaged_context =  &__mthp_khugepaged_context;
 		madvise_context =  &__madvise_context;
 		anon_ops = &__anon_ops;
 		return;
@@ -1565,13 +1584,14 @@ static void parse_test_type(int argc, ch
 
 	if (!strcmp(token, "all")) {
 		khugepaged_context =  &__khugepaged_context;
+		mthp_khugepaged_context =  &__mthp_khugepaged_context;
 		madvise_context =  &__madvise_context;
+		/* The mTHP context has only anon cases; let other mem_types drop it */
+		mthp_context_implied = true;
 	} else if (!strcmp(token, "khugepaged")) {
 		khugepaged_context =  &__khugepaged_context;
 	} else if (!strcmp(token, "mthp_khugepaged")) {
 		mthp_khugepaged_context =  &__mthp_khugepaged_context;
-		if (collapse_order <= 0 || collapse_order >= hpage_pmd_order)
-			usage();
 	} else if (!strcmp(token, "madvise")) {
 		madvise_context =  &__madvise_context;
 	} else {
@@ -1587,20 +1607,20 @@ static void parse_test_type(int argc, ch
 		read_write_file_write_ops =  &__read_write_file_write_ops;
 		anon_ops = &__anon_ops;
 		shmem_ops = &__shmem_ops;
-		if (mthp_khugepaged_context)
-			usage();
 	} else if (!strcmp(buf, "anon")) {
 		anon_ops = &__anon_ops;
 	} else if (!strcmp(buf, "file")) {
 		read_only_file_ops =  &__read_only_file_ops;
 		read_write_file_read_ops =  &__read_write_file_read_ops;
 		read_write_file_write_ops =  &__read_write_file_write_ops;
-		if (mthp_khugepaged_context)
+		if (mthp_khugepaged_context && !mthp_context_implied)
 			usage();
+		mthp_khugepaged_context = NULL;
 	} else if (!strcmp(buf, "shmem")) {
 		shmem_ops = &__shmem_ops;
-		if (mthp_khugepaged_context)
+		if (mthp_khugepaged_context && !mthp_context_implied)
 			usage();
+		mthp_khugepaged_context = NULL;
 	} else {
 		usage();
 	}
@@ -1622,6 +1642,7 @@ struct test_case {
 	struct mem_ops *ops;
 	const char *desc;
 	test_fn fn;
+	int order;		/* mTHP contexts: the collapse order */
 };
 
 #define MAX_TEST_CASES 256
@@ -1637,6 +1658,7 @@ static int nr_test_cases;
 			.ops	= o,					\
 			.desc	= #t,					\
 			.fn	= t,					\
+			.order	= collapse_order,			\
 		};							\
 	}								\
 	} while (0)
@@ -1677,13 +1699,35 @@ int main(int argc, char **argv)
 
 	parse_test_type(argc, argv);
 
-	if (mthp_khugepaged_context &&
-	    !(thp_supported_orders() & (1UL << collapse_order)))
-		ksft_exit_skip("Order %d is not a supported anon THP order\n",
-			       collapse_order);
-	if (mthp_khugepaged_context && collapse_order <= anon_order)
-		ksft_exit_skip("-c %d needs a source order below it, -s says %d\n",
-			       collapse_order, anon_order);
+	if (mthp_khugepaged_context) {
+		unsigned long orders = thp_supported_orders();
+
+		if (collapse_order_set) {
+			if (!(orders & (1UL << collapse_order)))
+				ksft_exit_skip("Order %d is not a supported anon THP order\n",
+					       collapse_order);
+			if (collapse_order <= anon_order)
+				ksft_exit_skip("-c %d needs a source order below it, -s says %d\n",
+					       collapse_order, anon_order);
+			collapse_orders[nr_collapse_orders++] = collapse_order;
+		} else {
+			/*
+			 * Every supported order above the source: -s makes the
+			 * fault path hand out folios of that order, so a target
+			 * at or below it has nothing to collapse.
+			 */
+			int first = anon_order + 1;
+
+			if (first < MIN_MTHP_ORDER)
+				first = MIN_MTHP_ORDER;
+			for (int i = first; i < hpage_pmd_order; i++) {
+				if (orders & (1UL << i))
+					collapse_orders[nr_collapse_orders++] = i;
+			}
+			if (!nr_collapse_orders)
+				ksft_print_msg("mTHP cases skipped: no order above the source\n");
+		}
+	}
 
 	if (mthp_khugepaged_context) {
 		pagemap_fd = open("/proc/self/pagemap", O_RDONLY);
@@ -1732,7 +1776,17 @@ int main(int argc, char **argv)
 	TEST(collapse_full, khugepaged_context, read_write_file_read_ops);
 	TEST(collapse_full, khugepaged_context, read_write_file_write_ops);
 	TEST(collapse_full, khugepaged_context, shmem_ops);
-	TEST(collapse_full, mthp_khugepaged_context, anon_ops);
+	for (int i = 0; i < nr_collapse_orders; i++) {
+		collapse_order = collapse_orders[i];
+		TEST(collapse_full, mthp_khugepaged_context, anon_ops);
+		TEST(collapse_empty, mthp_khugepaged_context, anon_ops);
+		TEST(collapse_single_mthp, mthp_khugepaged_context, anon_ops);
+		TEST(collapse_order_single_window, mthp_khugepaged_context, anon_ops);
+		TEST(collapse_order_partial_window, mthp_khugepaged_context, anon_ops);
+		TEST(collapse_order_max_ptes_none, mthp_khugepaged_context, anon_ops);
+		TEST(collapse_order_mixed_sources, mthp_khugepaged_context, anon_ops);
+	}
+
 	TEST(collapse_full, madvise_context, anon_ops);
 	TEST(collapse_full, madvise_context, read_only_file_ops);
 	TEST(collapse_full, madvise_context, read_write_file_read_ops);
@@ -1740,15 +1794,8 @@ int main(int argc, char **argv)
 	TEST(collapse_full, madvise_context, shmem_ops);
 
 	TEST(collapse_empty, khugepaged_context, anon_ops);
-	TEST(collapse_empty, mthp_khugepaged_context, anon_ops);
 	TEST(collapse_empty, madvise_context, anon_ops);
 
-	TEST(collapse_single_mthp, mthp_khugepaged_context, anon_ops);
-	TEST(collapse_order_single_window, mthp_khugepaged_context, anon_ops);
-	TEST(collapse_order_partial_window, mthp_khugepaged_context, anon_ops);
-	TEST(collapse_order_max_ptes_none, mthp_khugepaged_context, anon_ops);
-	TEST(collapse_order_mixed_sources, mthp_khugepaged_context, anon_ops);
-
 	TEST(collapse_single_pte_entry, khugepaged_context, anon_ops);
 	TEST(collapse_single_pte_entry, khugepaged_context, read_only_file_ops);
 	TEST(collapse_single_pte_entry, khugepaged_context, read_write_file_read_ops);
@@ -1821,7 +1868,15 @@ int main(int argc, char **argv)
 	for (int i = 0; i < nr_test_cases; i++) {
 		struct test_case *t = &test_cases[i];
 
-		ksft_print_msg("\n# Run test: %s (%s:%s)\n", t->desc, t->ctx->name, t->ops->name);
+		if (t->ctx == &__mthp_khugepaged_context) {
+			collapse_order = t->order;
+			ksft_print_msg("\n# Run test: %s (%s:%s, order %d)\n",
+				       t->desc, t->ctx->name, t->ops->name,
+				       t->order);
+		} else {
+			ksft_print_msg("\n# Run test: %s (%s:%s)\n", t->desc,
+				       t->ctx->name, t->ops->name);
+		}
 		t->fn(t->ctx, t->ops);
 	}
 
--- a/tools/testing/selftests/mm/run_vmtests.sh~selftests-mm-run-every-supported-collapse-order-by-default
+++ a/tools/testing/selftests/mm/run_vmtests.sh
@@ -392,8 +392,6 @@ CATEGORY="thp" run_test ./khugepaged all
 
 CATEGORY="thp" run_test ./khugepaged -s 4 all:shmem
 
-CATEGORY="thp" run_test ./khugepaged -c 4 mthp_khugepaged:anon
-
 # Try to create XFS if not provided
 if [ -z "${SPLIT_HUGE_PAGE_TEST_XFS_PATH}" ]; then
     if test_selected "thp"; then
_

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