+ kselftest-mm-remove-check_huge_shmem.patch added to mm-new branch

+ kselftest-mm-remove-check_huge_shmem.patch added to mm-new branch

[Andrew Morton]

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The patch titled
     Subject: kselftest: mm: remove check_huge_shmem()
has been added to the -mm mm-new branch.  Its filename is
     kselftest-mm-remove-check_huge_shmem.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/kselftest-mm-remove-check_huge_shmem.patch

This patch will later appear in the mm-new branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews.  Please do not hesitate to respond to
review feedback and post updated versions to replace or incrementally
fixup patches in mm-new.

The mm-new branch of mm.git is not included in linux-next

If a few days of testing in mm-new is successful, the patch will me moved
into mm.git's mm-unstable branch, which is included in linux-next

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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

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and is updated there most days

------------------------------------------------------
From: Yeoreum Yun <yeoreum.yun@arm.com>
Subject: kselftest: mm: remove check_huge_shmem()
Date: Thu, 24 Sep 2026 20:11:19 +0100

check_huge_shmem() was required to distinguish shmem huge pages because
/proc/self/smaps reports them using a dedicated “ShmemPmdMapped”
entry, as opposed to “FilePmdMapped” for file-backed huge pages.

Now that /proc/self/smaps is no longer used to detect huge pages and
/proc/kpageflags is used instead, it is sufficient to distinguish between
file-backed and anonymous pages since the ShmemPmdMapped is also kind of
file-backed.

Therefore, remove check_huge_shmem() and use check_huge_file() instead and
cleanup khugepaged's check_huge operation in mem_ops.

Link: https://lore.kernel.org/20260924-fix_split-v8-4-cba7359d882a@arm.com
Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Suggested-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: Zi Yan <ziy@nvidia.com>
Acked-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Nico Pache <nico.pache@linux.dev>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Usama Arif <usama.arif@linux.dev>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
---

 tools/testing/selftests/mm/folio_split_race_test.c |    2 
 tools/testing/selftests/mm/khugepaged.c            |   38 +----------
 tools/testing/selftests/mm/uffd-common.c           |    4 -
 tools/testing/selftests/mm/vm_util.c               |    5 -
 tools/testing/selftests/mm/vm_util.h               |    1 
 5 files changed, 9 insertions(+), 41 deletions(-)

--- a/tools/testing/selftests/mm/folio_split_race_test.c~kselftest-mm-remove-check_huge_shmem
+++ a/tools/testing/selftests/mm/folio_split_race_test.c
@@ -181,7 +181,7 @@ static uint64_t run_iteration(void)
 	for (i = 0; i < TOTAL_PAGES; i++)
 		fill_page(mmap_base, i);
 
-	if (!check_huge_shmem(mmap_base, FILE_SIZE, NR_PMD_PAGE, pmd_pagesize))
+	if (!check_huge_file(mmap_base, FILE_SIZE, NR_PMD_PAGE, pmd_pagesize))
 		ksft_exit_fail_msg("No shmem THP is allocated\n");
 
 	if (pthread_barrier_init(&ctl.barrier, NULL, NUM_READER_THREADS + 1) != 0)
--- a/tools/testing/selftests/mm/khugepaged.c~kselftest-mm-remove-check_huge_shmem
+++ a/tools/testing/selftests/mm/khugepaged.c
@@ -57,7 +57,7 @@ struct mem_ops {
 	void *(*setup_area)(int nr_hpages);
 	void (*cleanup_area)(void *p, unsigned long size);
 	void (*fault)(void *p, unsigned long start, unsigned long end);
-	bool (*check_huge)(void *addr, size_t len, int nr_hpages, unsigned long hpage_size);
+	bool (*check_huge)(void *addr, size_t len, int nr_hpages, uint64_t hpage_size);
 	const char *name;
 };
 
@@ -343,12 +343,6 @@ static void anon_fault(void *p, unsigned
 	fill_memory(p, start, end);
 }
 
-static bool anon_check_huge(void *addr, size_t len, int nr_hpages,
-		unsigned long hpage_size)
-{
-	return check_huge_anon(addr, len, nr_hpages, hpage_size);
-}
-
 static void *file_setup_area_common(int nr_hpages, enum file_setup_ops setup)
 {
 	const int open_opt = setup == FILE_SETUP_READ_ONLY_FS ? O_RDONLY : O_RDWR;
@@ -444,20 +438,6 @@ static void file_fault_write(void *p, un
 		ksft_exit_fail_perror("madvise(MADV_POPULATE_WRITE)");
 }
 
-static bool file_check_huge(void *addr, size_t len, int nr_hpages,
-		unsigned long hpage_size)
-{
-	switch (finfo.type) {
-	case VMA_FILE:
-		return check_huge_file(addr, len, nr_hpages, hpage_size);
-	case VMA_SHMEM:
-		return check_huge_shmem(addr, len, nr_hpages, hpage_size);
-	default:
-		ksft_exit_fail_msg("Unknown VMA type\n");
-		return false;
-	}
-}
-
 static void *shmem_setup_area(int nr_hpages)
 {
 	void *p;
@@ -481,17 +461,11 @@ static void shmem_cleanup_area(void *p,
 	close(finfo.fd);
 }
 
-static bool shmem_check_huge(void *addr, size_t len, int nr_hpages,
-		unsigned long hpage_size)
-{
-	return check_huge_shmem(addr, len, nr_hpages, hpage_size);
-}
-
 static struct mem_ops __anon_ops = {
 	.setup_area = &anon_setup_area,
 	.cleanup_area = &anon_cleanup_area,
 	.fault = &anon_fault,
-	.check_huge = &anon_check_huge,
+	.check_huge = &check_huge_anon,
 	.name = "anon",
 };
 
@@ -499,7 +473,7 @@ static struct mem_ops __read_only_file_o
 	.setup_area = &file_setup_read_only_area,
 	.cleanup_area = &file_cleanup_area,
 	.fault = &file_fault_read,
-	.check_huge = &file_check_huge,
+	.check_huge = &check_huge_file,
 	.name = "file",
 };
 
@@ -507,7 +481,7 @@ static struct mem_ops __read_write_file_
 	.setup_area = &file_setup_read_write_fs_read_area,
 	.cleanup_area = &file_cleanup_area,
 	.fault = &file_fault_read_and_flush,
-	.check_huge = &file_check_huge,
+	.check_huge = &check_huge_file,
 	.name = "file",
 };
 
@@ -515,7 +489,7 @@ static struct mem_ops __read_write_file_
 	.setup_area = &file_setup_read_write_fs_write_area,
 	.cleanup_area = &file_cleanup_area,
 	.fault = &file_fault_write,
-	.check_huge = &file_check_huge,
+	.check_huge = &check_huge_file,
 	.name = "file",
 };
 
@@ -523,7 +497,7 @@ static struct mem_ops __shmem_ops = {
 	.setup_area = &shmem_setup_area,
 	.cleanup_area = &shmem_cleanup_area,
 	.fault = &anon_fault,
-	.check_huge = &shmem_check_huge,
+	.check_huge = &check_huge_file,
 	.name = "shmem",
 };
 
--- a/tools/testing/selftests/mm/uffd-common.c~kselftest-mm-remove-check_huge_shmem
+++ a/tools/testing/selftests/mm/uffd-common.c
@@ -196,8 +196,8 @@ static void shmem_check_pmd_mapping(uffd
 {
 	size_t len = expect_nr_hpages * read_pmd_pagesize();
 
-	if (!check_huge_shmem(gopts->area_dst_alias, len, expect_nr_hpages,
-			      read_pmd_pagesize()))
+	if (!check_huge_file(gopts->area_dst_alias, len, expect_nr_hpages,
+			     read_pmd_pagesize()))
 		err("Did not find expected %d number of hugepages",
 		    expect_nr_hpages);
 }
--- a/tools/testing/selftests/mm/vm_util.c~kselftest-mm-remove-check_huge_shmem
+++ a/tools/testing/selftests/mm/vm_util.c
@@ -470,11 +470,6 @@ bool check_huge_file(void *addr, size_t
 	return __check_huge(addr, len, nr_hpages, hpage_size, CHECK_HUGE_FILE);
 }
 
-bool check_huge_shmem(void *addr, size_t len, int nr_hpages, uint64_t hpage_size)
-{
-	return check_huge_file(addr, len, nr_hpages, hpage_size);
-}
-
 int64_t allocate_transhuge(void *ptr, int pagemap_fd)
 {
 	uint64_t ent[2];
--- a/tools/testing/selftests/mm/vm_util.h~kselftest-mm-remove-check_huge_shmem
+++ a/tools/testing/selftests/mm/vm_util.h
@@ -96,7 +96,6 @@ uint64_t read_pmd_pagesize(void);
 unsigned long rss_anon(void);
 bool check_huge_anon(void *addr, size_t len, int nr_hpages, uint64_t hpage_size);
 bool check_huge_file(void *addr, size_t len, int nr_hpages, uint64_t hpage_size);
-bool check_huge_shmem(void *addr, size_t len, int nr_hpages, uint64_t hpage_size);
 int64_t allocate_transhuge(void *ptr, int pagemap_fd);
 int pageflags_get(unsigned long pfn, int kpageflags_fd, uint64_t *flags);
 int gather_folio_orders(char *vaddr_start, size_t len,
_

Patches currently in -mm which might be from yeoreum.yun@arm.com are

kselftest-mm-fix-potential-failure-for-merged-vma-in-guard-regions.patch
kselftest-mm-remove-exclusion-of-building-soft-dirty-test-in-arm64.patch
kselftest-mm-return-fail-when-child-test-result-is-fail-in-khugepaged.patch
kselftest-mm-fix-intermittent-failure-khugepaged-test.patch
kselftest-mm-prevent-random-failure-of-huge-page-split-for-khugepaged.patch
kselftest-mm-replace-usage-of-proc-self-smaps-for-__check_pmd_huge.patch
kselftest-mm-integrate-huge-page-checks.patch
kselftest-mm-remove-check_huge_shmem.patch