[PATCH mm-unstable v3 08/10] selftests/vm: add thp collapse shmem testing

["Zach O'Keefe" <zokeefe@google.com>]

Add memory operations for shmem (memfd) memory, and reuse
existing tests with the new memory operations.

Shmem tests can be called with "shmem" mem_type, and shmem tests
are ran with "all" mem_type as well.

Signed-off-by: Zach O'Keefe <zokeefe@google.com>
---
 tools/testing/selftests/vm/khugepaged.c | 57 ++++++++++++++++++++++++-
 1 file changed, 55 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/vm/khugepaged.c b/tools/testing/selftests/vm/khugepaged.c
index 59f56a329f43..05d9945daa48 100644
--- a/tools/testing/selftests/vm/khugepaged.c
+++ b/tools/testing/selftests/vm/khugepaged.c
@@ -58,6 +58,7 @@ struct mem_ops {
 
 static struct mem_ops *file_ops;
 static struct mem_ops *anon_ops;
+static struct mem_ops *shmem_ops;
 
 struct collapse_context {
 	void (*collapse)(const char *msg, char *p, int nr_hpages,
@@ -708,6 +709,40 @@ static bool file_check_huge(void *addr, int nr_hpages)
 	}
 }
 
+static void *shmem_setup_area(int nr_hpages)
+{
+	void *p;
+	unsigned long size = nr_hpages * hpage_pmd_size;
+
+	finfo.fd = memfd_create("khugepaged-selftest-collapse-shmem", 0);
+	if (finfo.fd < 0)  {
+		perror("memfd_create()");
+		exit(EXIT_FAILURE);
+	}
+	if (ftruncate(finfo.fd, size)) {
+		perror("ftruncate()");
+		exit(EXIT_FAILURE);
+	}
+	p = mmap(BASE_ADDR, size, PROT_READ | PROT_WRITE, MAP_SHARED, finfo.fd,
+		 0);
+	if (p != BASE_ADDR) {
+		perror("mmap()");
+		exit(EXIT_FAILURE);
+	}
+	return p;
+}
+
+static void shmem_cleanup_area(void *p, unsigned long size)
+{
+	munmap(p, size);
+	close(finfo.fd);
+}
+
+static bool shmem_check_huge(void *addr, int nr_hpages)
+{
+	return check_huge_shmem(addr, nr_hpages, hpage_pmd_size);
+}
+
 static struct mem_ops __anon_ops = {
 	.setup_area = &anon_setup_area,
 	.cleanup_area = &anon_cleanup_area,
@@ -724,6 +759,14 @@ static struct mem_ops __file_ops = {
 	.name = "file",
 };
 
+static struct mem_ops __shmem_ops = {
+	.setup_area = &shmem_setup_area,
+	.cleanup_area = &shmem_cleanup_area,
+	.fault = &anon_fault,
+	.check_huge = &shmem_check_huge,
+	.name = "shmem",
+};
+
 static void __madvise_collapse(const char *msg, char *p, int nr_hpages,
 			       struct mem_ops *ops, bool expect)
 {
@@ -1285,7 +1328,7 @@ static void usage(void)
 	fprintf(stderr, "\nUsage: ./khugepaged <test type> [dir]\n\n");
 	fprintf(stderr, "\t<test type>\t: <context>:<mem_type>\n");
 	fprintf(stderr, "\t<context>\t: [all|khugepaged|madvise]\n");
-	fprintf(stderr, "\t<mem_type>\t: [all|anon|file]\n");
+	fprintf(stderr, "\t<mem_type>\t: [all|anon|file|shmem]\n");
 	fprintf(stderr, "\n\t\"file,all\" mem_type requires [dir] argument\n");
 	fprintf(stderr, "\n\t\"file,all\" mem_type requires kernel built with\n");
 	fprintf(stderr,	"\tCONFIG_READ_ONLY_THP_FOR_FS=y\n");
@@ -1327,10 +1370,13 @@ static void parse_test_type(int argc, const char **argv)
 	if (!strcmp(buf, "all")) {
 		file_ops =  &__file_ops;
 		anon_ops = &__anon_ops;
+		shmem_ops = &__shmem_ops;
 	} else if (!strcmp(buf, "anon")) {
 		anon_ops = &__anon_ops;
 	} else if (!strcmp(buf, "file")) {
 		file_ops =  &__file_ops;
+	} else if (!strcmp(buf, "shmem")) {
+		shmem_ops = &__shmem_ops;
 	} else {
 		usage();
 	}
@@ -1347,7 +1393,7 @@ int main(int argc, const char **argv)
 	struct settings default_settings = {
 		.thp_enabled = THP_MADVISE,
 		.thp_defrag = THP_DEFRAG_ALWAYS,
-		.shmem_enabled = SHMEM_NEVER,
+		.shmem_enabled = SHMEM_ADVISE,
 		.use_zero_page = 0,
 		.khugepaged = {
 			.defrag = 1,
@@ -1394,16 +1440,20 @@ int main(int argc, const char **argv)
 
 	TEST(collapse_full, khugepaged_context, anon_ops);
 	TEST(collapse_full, khugepaged_context, file_ops);
+	TEST(collapse_full, khugepaged_context, shmem_ops);
 	TEST(collapse_full, madvise_context, anon_ops);
 	TEST(collapse_full, madvise_context, file_ops);
+	TEST(collapse_full, madvise_context, shmem_ops);
 
 	TEST(collapse_empty, khugepaged_context, anon_ops);
 	TEST(collapse_empty, madvise_context, anon_ops);
 
 	TEST(collapse_single_pte_entry, khugepaged_context, anon_ops);
 	TEST(collapse_single_pte_entry, khugepaged_context, file_ops);
+	TEST(collapse_single_pte_entry, khugepaged_context, shmem_ops);
 	TEST(collapse_single_pte_entry, madvise_context, anon_ops);
 	TEST(collapse_single_pte_entry, madvise_context, file_ops);
+	TEST(collapse_single_pte_entry, madvise_context, shmem_ops);
 
 	TEST(collapse_max_ptes_none, khugepaged_context, anon_ops);
 	TEST(collapse_max_ptes_none, khugepaged_context, file_ops);
@@ -1417,8 +1467,10 @@ int main(int argc, const char **argv)
 
 	TEST(collapse_full_of_compound, khugepaged_context, anon_ops);
 	TEST(collapse_full_of_compound, khugepaged_context, file_ops);
+	TEST(collapse_full_of_compound, khugepaged_context, shmem_ops);
 	TEST(collapse_full_of_compound, madvise_context, anon_ops);
 	TEST(collapse_full_of_compound, madvise_context, file_ops);
+	TEST(collapse_full_of_compound, madvise_context, shmem_ops);
 
 	TEST(collapse_compound_extreme, khugepaged_context, anon_ops);
 	TEST(collapse_compound_extreme, madvise_context, anon_ops);
@@ -1440,6 +1492,7 @@ int main(int argc, const char **argv)
 
 	TEST(madvise_collapse_existing_thps, madvise_context, anon_ops);
 	TEST(madvise_collapse_existing_thps, madvise_context, file_ops);
+	TEST(madvise_collapse_existing_thps, madvise_context, shmem_ops);
 
 	restore_settings(0);
 }
-- 
2.37.2.789.g6183377224-goog