selftests/vm: modularize thp collapse memory operations

Modularize operations to setup, cleanup, fault, and check for huge pages,
for a given memory type.  This allows reusing existing tests with
additional memory types by defining new memory operations.  Following
patches will add file and shmem memory types.

Link: https://lkml.kernel.org/r/20220907144521.3115321-7-zokeefe@google.com
Link: https://lkml.kernel.org/r/20220922224046.1143204-7-zokeefe@google.com
Signed-off-by: Zach O'Keefe <zokeefe@google.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Chris Kennelly <ckennelly@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Houghton <jthoughton@google.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rongwei Wang <rongwei.wang@linux.alibaba.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 207 insertions, 166 deletions

diff --git a/tools/testing/selftests/vm/khugepaged.c b/tools/testing/selftests/vm/khugepaged.c
index 235a64b4458c..06ea6f18980e 100644
--- a/tools/testing/selftests/vm/khugepaged.c
+++ b/tools/testing/selftests/vm/khugepaged.c
@@ -29,8 +29,16 @@ static int hpage_pmd_nr;
 #define THP_SYSFS "/sys/kernel/mm/transparent_hugepage/"
 #define PID_SMAPS "/proc/self/smaps"
 
+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, int nr_hpages);
+};
+
 struct collapse_context {
-	void (*collapse)(const char *msg, char *p, int nr_hpages, bool expect);
+	void (*collapse)(const char *msg, char *p, int nr_hpages,
+			 struct mem_ops *ops, bool expect);
 	bool enforce_pte_scan_limits;
 };
 
@@ -354,11 +362,6 @@ static void save_settings(void)
 	signal(SIGQUIT, restore_settings);
 }
 
-static bool check_huge(void *addr, int nr_hpages)
-{
-	return check_huge_anon(addr, nr_hpages, hpage_pmd_size);
-}
-
 #define MAX_LINE_LENGTH 500
 static bool check_swap(void *addr, unsigned long size)
 {
@@ -452,18 +455,33 @@ retry:
  * Returns pmd-mapped hugepage in VMA marked VM_HUGEPAGE, filled with
  * validate_memory()'able contents.
  */
-static void *alloc_hpage(void)
+static void *alloc_hpage(struct mem_ops *ops)
 {
-	void *p;
+	void *p = ops->setup_area(1);
 
-	p = alloc_mapping(1);
+	ops->fault(p, 0, hpage_pmd_size);
+
+	/*
+	 * VMA should be neither VM_HUGEPAGE nor VM_NOHUGEPAGE.
+	 * The latter is ineligible for collapse by MADV_COLLAPSE
+	 * while the former might cause MADV_COLLAPSE to race with
+	 * khugepaged on low-load system (like a test machine), which
+	 * would cause MADV_COLLAPSE to fail with EAGAIN.
+	 */
 	printf("Allocate huge page...");
-	madvise(p, hpage_pmd_size, MADV_HUGEPAGE);
-	fill_memory(p, 0, hpage_pmd_size);
-	if (check_huge(p, 1))
-		success("OK");
-	else
-		fail("Fail");
+	if (madvise_collapse_retry(p, hpage_pmd_size)) {
+		perror("madvise(MADV_COLLAPSE)");
+		exit(EXIT_FAILURE);
+	}
+	if (!ops->check_huge(p, 1)) {
+		perror("madvise(MADV_COLLAPSE)");
+		exit(EXIT_FAILURE);
+	}
+	if (madvise(p, hpage_pmd_size, MADV_HUGEPAGE)) {
+		perror("madvise(MADV_HUGEPAGE)");
+		exit(EXIT_FAILURE);
+	}
+	success("OK");
 	return p;
 }
 
@@ -480,18 +498,40 @@ static void validate_memory(int *p, unsigned long start, unsigned long end)
 	}
 }
 
-static void madvise_collapse(const char *msg, char *p, int nr_hpages,
-			     bool expect)
+static void *anon_setup_area(int nr_hpages)
+{
+	return alloc_mapping(nr_hpages);
+}
+
+static void anon_cleanup_area(void *p, unsigned long size)
+{
+	munmap(p, size);
+}
+
+static void anon_fault(void *p, unsigned long start, unsigned long end)
+{
+	fill_memory(p, start, end);
+}
+
+static bool anon_check_huge(void *addr, int nr_hpages)
+{
+	return check_huge_anon(addr, nr_hpages, hpage_pmd_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,
+};
+
+static void __madvise_collapse(const char *msg, char *p, int nr_hpages,
+			       struct mem_ops *ops, bool expect)
 {
 	int ret;
 	struct settings settings = *current_settings();
 
 	printf("%s...", msg);
-	/* Sanity check */
-	if (!check_huge(p, 0)) {
-		printf("Unexpected huge page\n");
-		exit(EXIT_FAILURE);
-	}
 
 	/*
 	 * Prevent khugepaged interference and tests that MADV_COLLAPSE
@@ -505,7 +545,7 @@ static void madvise_collapse(const char *msg, char *p, int nr_hpages,
 	ret = madvise_collapse_retry(p, nr_hpages * hpage_pmd_size);
 	if (((bool)ret) == expect)
 		fail("Fail: Bad return value");
-	else if (check_huge(p, nr_hpages) != expect)
+	else if (!ops->check_huge(p, expect ? nr_hpages : 0))
 		fail("Fail: check_huge()");
 	else
 		success("OK");
@@ -513,14 +553,26 @@ static void madvise_collapse(const char *msg, char *p, int nr_hpages,
 	pop_settings();
 }
 
+static void madvise_collapse(const char *msg, char *p, int nr_hpages,
+			     struct mem_ops *ops, bool expect)
+{
+	/* Sanity check */
+	if (!ops->check_huge(p, 0)) {
+		printf("Unexpected huge page\n");
+		exit(EXIT_FAILURE);
+	}
+	__madvise_collapse(msg, p, nr_hpages, ops, expect);
+}
+
 #define TICK 500000
-static bool wait_for_scan(const char *msg, char *p, int nr_hpages)
+static bool wait_for_scan(const char *msg, char *p, int nr_hpages,
+			  struct mem_ops *ops)
 {
 	int full_scans;
 	int timeout = 6; /* 3 seconds */
 
 	/* Sanity check */
-	if (!check_huge(p, 0)) {
+	if (!ops->check_huge(p, 0)) {
 		printf("Unexpected huge page\n");
 		exit(EXIT_FAILURE);
 	}
@@ -532,7 +584,7 @@ static bool wait_for_scan(const char *msg, char *p, int nr_hpages)
 
 	printf("%s...", msg);
 	while (timeout--) {
-		if (check_huge(p, nr_hpages))
+		if (ops->check_huge(p, nr_hpages))
 			break;
 		if (read_num("khugepaged/full_scans") >= full_scans)
 			break;
@@ -546,19 +598,20 @@ static bool wait_for_scan(const char *msg, char *p, int nr_hpages)
 }
 
 static void khugepaged_collapse(const char *msg, char *p, int nr_hpages,
-				bool expect)
+				struct mem_ops *ops, bool expect)
 {
-	if (wait_for_scan(msg, p, nr_hpages)) {
+	if (wait_for_scan(msg, p, nr_hpages, ops)) {
 		if (expect)
 			fail("Timeout");
 		else
 			success("OK");
 		return;
-	} else if (check_huge(p, nr_hpages) == expect) {
+	}
+
+	if (ops->check_huge(p, expect ? nr_hpages : 0))
 		success("OK");
-	} else {
+	else
 		fail("Fail");
-	}
 }
 
 static void alloc_at_fault(void)
@@ -572,7 +625,7 @@ static void alloc_at_fault(void)
 	p = alloc_mapping(1);
 	*p = 1;
 	printf("Allocate huge page on fault...");
-	if (check_huge(p, 1))
+	if (check_huge_anon(p, 1, hpage_pmd_size))
 		success("OK");
 	else
 		fail("Fail");
@@ -581,49 +634,48 @@ static void alloc_at_fault(void)
 
 	madvise(p, page_size, MADV_DONTNEED);
 	printf("Split huge PMD on MADV_DONTNEED...");
-	if (check_huge(p, 0))
+	if (check_huge_anon(p, 0, hpage_pmd_size))
 		success("OK");
 	else
 		fail("Fail");
 	munmap(p, hpage_pmd_size);
 }
 
-static void collapse_full(struct collapse_context *c)
+static void collapse_full(struct collapse_context *c, struct mem_ops *ops)
 {
 	void *p;
 	int nr_hpages = 4;
 	unsigned long size = nr_hpages * hpage_pmd_size;
 
-	p = alloc_mapping(nr_hpages);
-	fill_memory(p, 0, size);
+	p = ops->setup_area(nr_hpages);
+	ops->fault(p, 0, size);
 	c->collapse("Collapse multiple fully populated PTE table", p, nr_hpages,
-		    true);
+		    ops, true);
 	validate_memory(p, 0, size);
-	munmap(p, size);
+	ops->cleanup_area(p, size);
 }
 
-static void collapse_empty(struct collapse_context *c)
+static void collapse_empty(struct collapse_context *c, struct mem_ops *ops)
 {
 	void *p;
 
-	p = alloc_mapping(1);
-	c->collapse("Do not collapse empty PTE table", p, 1, false);
-	munmap(p, hpage_pmd_size);
+	p = ops->setup_area(1);
+	c->collapse("Do not collapse empty PTE table", p, 1, ops, false);
+	ops->cleanup_area(p, hpage_pmd_size);
 }
 
-static void collapse_single_pte_entry(struct collapse_context *c)
+static void collapse_single_pte_entry(struct collapse_context *c, struct mem_ops *ops)
 {
 	void *p;
 
-	p = alloc_mapping(1);
-	fill_memory(p, 0, page_size);
+	p = ops->setup_area(1);
+	ops->fault(p, 0, page_size);
 	c->collapse("Collapse PTE table with single PTE entry present", p,
-		    1, true);
-	validate_memory(p, 0, page_size);
-	munmap(p, hpage_pmd_size);
+		    1, ops, true);
+	ops->cleanup_area(p, hpage_pmd_size);
 }
 
-static void collapse_max_ptes_none(struct collapse_context *c)
+static void collapse_max_ptes_none(struct collapse_context *c, struct mem_ops *ops)
 {
 	int max_ptes_none = hpage_pmd_nr / 2;
 	struct settings settings = *current_settings();
@@ -632,30 +684,30 @@ static void collapse_max_ptes_none(struct collapse_context *c)
 	settings.khugepaged.max_ptes_none = max_ptes_none;
 	push_settings(&settings);
 
-	p = alloc_mapping(1);
+	p = ops->setup_area(1);
 
-	fill_memory(p, 0, (hpage_pmd_nr - max_ptes_none - 1) * page_size);
+	ops->fault(p, 0, (hpage_pmd_nr - max_ptes_none - 1) * page_size);
 	c->collapse("Maybe collapse with max_ptes_none exceeded", p, 1,
-		    !c->enforce_pte_scan_limits);
+		    ops, !c->enforce_pte_scan_limits);
 	validate_memory(p, 0, (hpage_pmd_nr - max_ptes_none - 1) * page_size);
 
 	if (c->enforce_pte_scan_limits) {
-		fill_memory(p, 0, (hpage_pmd_nr - max_ptes_none) * page_size);
-		c->collapse("Collapse with max_ptes_none PTEs empty", p, 1,
+		ops->fault(p, 0, (hpage_pmd_nr - max_ptes_none) * page_size);
+		c->collapse("Collapse with max_ptes_none PTEs empty", p, 1, ops,
 			    true);
 		validate_memory(p, 0,
 				(hpage_pmd_nr - max_ptes_none) * page_size);
 	}
-
-	munmap(p, hpage_pmd_size);
+	ops->cleanup_area(p, hpage_pmd_size);
 	pop_settings();
 }
 
-static void collapse_swapin_single_pte(struct collapse_context *c)
+static void collapse_swapin_single_pte(struct collapse_context *c, struct mem_ops *ops)
 {
 	void *p;
-	p = alloc_mapping(1);
-	fill_memory(p, 0, hpage_pmd_size);
+
+	p = ops->setup_area(1);
+	ops->fault(p, 0, hpage_pmd_size);
 
 	printf("Swapout one page...");
 	if (madvise(p, page_size, MADV_PAGEOUT)) {
@@ -669,20 +721,21 @@ static void collapse_swapin_single_pte(struct collapse_context *c)
 		goto out;
 	}
 
-	c->collapse("Collapse with swapping in single PTE entry", p, 1, true);
+	c->collapse("Collapse with swapping in single PTE entry", p, 1, ops,
+		    true);
 	validate_memory(p, 0, hpage_pmd_size);
 out:
-	munmap(p, hpage_pmd_size);
+	ops->cleanup_area(p, hpage_pmd_size);
 }
 
-static void collapse_max_ptes_swap(struct collapse_context *c)
+static void collapse_max_ptes_swap(struct collapse_context *c, struct mem_ops *ops)
 {
 	int max_ptes_swap = read_num("khugepaged/max_ptes_swap");
 	void *p;
 
-	p = alloc_mapping(1);
+	p = ops->setup_area(1);
+	ops->fault(p, 0, hpage_pmd_size);
 
-	fill_memory(p, 0, hpage_pmd_size);
 	printf("Swapout %d of %d pages...", max_ptes_swap + 1, hpage_pmd_nr);
 	if (madvise(p, (max_ptes_swap + 1) * page_size, MADV_PAGEOUT)) {
 		perror("madvise(MADV_PAGEOUT)");
@@ -695,12 +748,12 @@ static void collapse_max_ptes_swap(struct collapse_context *c)
 		goto out;
 	}
 
-	c->collapse("Maybe collapse with max_ptes_swap exceeded", p, 1,
+	c->collapse("Maybe collapse with max_ptes_swap exceeded", p, 1, ops,
 		    !c->enforce_pte_scan_limits);
 	validate_memory(p, 0, hpage_pmd_size);
 
 	if (c->enforce_pte_scan_limits) {
-		fill_memory(p, 0, hpage_pmd_size);
+		ops->fault(p, 0, hpage_pmd_size);
 		printf("Swapout %d of %d pages...", max_ptes_swap,
 		       hpage_pmd_nr);
 		if (madvise(p, max_ptes_swap * page_size, MADV_PAGEOUT)) {
@@ -715,63 +768,65 @@ static void collapse_max_ptes_swap(struct collapse_context *c)
 		}
 
 		c->collapse("Collapse with max_ptes_swap pages swapped out", p,
-			    1, true);
+			    1, ops, true);
 		validate_memory(p, 0, hpage_pmd_size);
 	}
 out:
-	munmap(p, hpage_pmd_size);
+	ops->cleanup_area(p, hpage_pmd_size);
 }
 
-static void collapse_single_pte_entry_compound(struct collapse_context *c)
+static void collapse_single_pte_entry_compound(struct collapse_context *c, struct mem_ops *ops)
 {
 	void *p;
 
-	p = alloc_hpage();
+	p = alloc_hpage(ops);
+
 	madvise(p, hpage_pmd_size, MADV_NOHUGEPAGE);
 	printf("Split huge page leaving single PTE mapping compound page...");
 	madvise(p + page_size, hpage_pmd_size - page_size, MADV_DONTNEED);
-	if (check_huge(p, 0))
+	if (ops->check_huge(p, 0))
 		success("OK");
 	else
 		fail("Fail");
 
 	c->collapse("Collapse PTE table with single PTE mapping compound page",
-		    p, 1, true);
+		    p, 1, ops, true);
 	validate_memory(p, 0, page_size);
-	munmap(p, hpage_pmd_size);
+	ops->cleanup_area(p, hpage_pmd_size);
 }
 
-static void collapse_full_of_compound(struct collapse_context *c)
+static void collapse_full_of_compound(struct collapse_context *c, struct mem_ops *ops)
 {
 	void *p;
 
-	p = alloc_hpage();
+	p = alloc_hpage(ops);
 	printf("Split huge page leaving single PTE page table full of compound pages...");
 	madvise(p, page_size, MADV_NOHUGEPAGE);
 	madvise(p, hpage_pmd_size, MADV_NOHUGEPAGE);
-	if (check_huge(p, 0))
+	if (ops->check_huge(p, 0))
 		success("OK");
 	else
 		fail("Fail");
 
-	c->collapse("Collapse PTE table full of compound pages", p, 1, true);
+	c->collapse("Collapse PTE table full of compound pages", p, 1, ops,
+		    true);
 	validate_memory(p, 0, hpage_pmd_size);
-	munmap(p, hpage_pmd_size);
+	ops->cleanup_area(p, hpage_pmd_size);
 }
 
-static void collapse_compound_extreme(struct collapse_context *c)
+static void collapse_compound_extreme(struct collapse_context *c, struct mem_ops *ops)
 {
 	void *p;
 	int i;
 
-	p = alloc_mapping(1);
+	p = ops->setup_area(1);
 	for (i = 0; i < hpage_pmd_nr; i++) {
 		printf("\rConstruct PTE page table full of different PTE-mapped compound pages %3d/%d...",
 				i + 1, hpage_pmd_nr);
 
 		madvise(BASE_ADDR, hpage_pmd_size, MADV_HUGEPAGE);
-		fill_memory(BASE_ADDR, 0, hpage_pmd_size);
-		if (!check_huge(BASE_ADDR, 1)) {
+		ops->fault(BASE_ADDR, 0, hpage_pmd_size);
+		if (!ops->check_huge(BASE_ADDR, 1)) {
 			printf("Failed to allocate huge page\n");
 			exit(EXIT_FAILURE);
 		}
@@ -798,30 +853,30 @@ static void collapse_compound_extreme(struct collapse_context *c)
 		}
 	}
 
-	munmap(BASE_ADDR, hpage_pmd_size);
-	fill_memory(p, 0, hpage_pmd_size);
-	if (check_huge(p, 0))
+	ops->cleanup_area(BASE_ADDR, hpage_pmd_size);
+	ops->fault(p, 0, hpage_pmd_size);
+	if (!ops->check_huge(p, 1))
 		success("OK");
 	else
 		fail("Fail");
 
 	c->collapse("Collapse PTE table full of different compound pages", p, 1,
-		    true);
+		    ops, true);
 
 	validate_memory(p, 0, hpage_pmd_size);
-	munmap(p, hpage_pmd_size);
+	ops->cleanup_area(p, hpage_pmd_size);
 }
 
-static void collapse_fork(struct collapse_context *c)
+static void collapse_fork(struct collapse_context *c, struct mem_ops *ops)
 {
 	int wstatus;
 	void *p;
 
-	p = alloc_mapping(1);
+	p = ops->setup_area(1);
 
 	printf("Allocate small page...");
-	fill_memory(p, 0, page_size);
-	if (check_huge(p, 0))
+	ops->fault(p, 0, page_size);
+	if (ops->check_huge(p, 0))
 		success("OK");
 	else
 		fail("Fail");
@@ -832,17 +887,17 @@ static void collapse_fork(struct collapse_context *c)
 		skip_settings_restore = true;
 		exit_status = 0;
 
-		if (check_huge(p, 0))
+		if (ops->check_huge(p, 0))
 			success("OK");
 		else
 			fail("Fail");
 
-		fill_memory(p, page_size, 2 * page_size);
+		ops->fault(p, page_size, 2 * page_size);
 		c->collapse("Collapse PTE table with single page shared with parent process",
-			    p, 1, true);
+			    p, 1, ops, true);
 
 		validate_memory(p, 0, page_size);
-		munmap(p, hpage_pmd_size);
+		ops->cleanup_area(p, hpage_pmd_size);
 		exit(exit_status);
 	}
 
@@ -850,27 +905,27 @@ static void collapse_fork(struct collapse_context *c)
 	exit_status += WEXITSTATUS(wstatus);
 
 	printf("Check if parent still has small page...");
-	if (check_huge(p, 0))
+	if (ops->check_huge(p, 0))
 		success("OK");
 	else
 		fail("Fail");
 	validate_memory(p, 0, page_size);
-	munmap(p, hpage_pmd_size);
+	ops->cleanup_area(p, hpage_pmd_size);
 }
 
-static void collapse_fork_compound(struct collapse_context *c)
+static void collapse_fork_compound(struct collapse_context *c, struct mem_ops *ops)
 {
 	int wstatus;
 	void *p;
 
-	p = alloc_hpage();
+	p = alloc_hpage(ops);
 	printf("Share huge page over fork()...");
 	if (!fork()) {
 		/* Do not touch settings on child exit */
 		skip_settings_restore = true;
 		exit_status = 0;
 
-		if (check_huge(p, 1))
+		if (ops->check_huge(p, 1))
 			success("OK");
 		else
 			fail("Fail");
@@ -878,20 +933,20 @@ static void collapse_fork_compound(struct collapse_context *c)
 		printf("Split huge page PMD in child process...");
 		madvise(p, page_size, MADV_NOHUGEPAGE);
 		madvise(p, hpage_pmd_size, MADV_NOHUGEPAGE);
-		if (check_huge(p, 0))
+		if (ops->check_huge(p, 0))
 			success("OK");
 		else
 			fail("Fail");
-		fill_memory(p, 0, page_size);
+		ops->fault(p, 0, page_size);
 
 		write_num("khugepaged/max_ptes_shared", hpage_pmd_nr - 1);
 		c->collapse("Collapse PTE table full of compound pages in child",
-			    p, 1, true);
+			    p, 1, ops, true);
 		write_num("khugepaged/max_ptes_shared",
 			  current_settings()->khugepaged.max_ptes_shared);
 
 		validate_memory(p, 0, hpage_pmd_size);
-		munmap(p, hpage_pmd_size);
+		ops->cleanup_area(p, hpage_pmd_size);
 		exit(exit_status);
 	}
 
@@ -899,59 +954,59 @@ static void collapse_fork_compound(struct collapse_context *c)
 	exit_status += WEXITSTATUS(wstatus);
 
 	printf("Check if parent still has huge page...");
-	if (check_huge(p, 1))
+	if (ops->check_huge(p, 1))
 		success("OK");
 	else
 		fail("Fail");
 	validate_memory(p, 0, hpage_pmd_size);
-	munmap(p, hpage_pmd_size);
+	ops->cleanup_area(p, hpage_pmd_size);
 }
 
-static void collapse_max_ptes_shared(struct collapse_context *c)
+static void collapse_max_ptes_shared(struct collapse_context *c, struct mem_ops *ops)
 {
 	int max_ptes_shared = read_num("khugepaged/max_ptes_shared");
 	int wstatus;
 	void *p;
 
-	p = alloc_hpage();
+	p = alloc_hpage(ops);
 	printf("Share huge page over fork()...");
 	if (!fork()) {
 		/* Do not touch settings on child exit */
 		skip_settings_restore = true;
 		exit_status = 0;
 
-		if (check_huge(p, 1))
+		if (ops->check_huge(p, 1))
 			success("OK");
 		else
 			fail("Fail");
 
 		printf("Trigger CoW on page %d of %d...",
 				hpage_pmd_nr - max_ptes_shared - 1, hpage_pmd_nr);
-		fill_memory(p, 0, (hpage_pmd_nr - max_ptes_shared - 1) * page_size);
-		if (check_huge(p, 0))
+		ops->fault(p, 0, (hpage_pmd_nr - max_ptes_shared - 1) * page_size);
+		if (ops->check_huge(p, 0))
 			success("OK");
 		else
 			fail("Fail");
 
 		c->collapse("Maybe collapse with max_ptes_shared exceeded", p,
-			    1, !c->enforce_pte_scan_limits);
+			    1, ops, !c->enforce_pte_scan_limits);
 
 		if (c->enforce_pte_scan_limits) {
 			printf("Trigger CoW on page %d of %d...",
 			       hpage_pmd_nr - max_ptes_shared, hpage_pmd_nr);
-			fill_memory(p, 0, (hpage_pmd_nr - max_ptes_shared) *
+			ops->fault(p, 0, (hpage_pmd_nr - max_ptes_shared) *
 				    page_size);
-			if (check_huge(p, 0))
+			if (ops->check_huge(p, 0))
 				success("OK");
 			else
 				fail("Fail");
 
 			c->collapse("Collapse with max_ptes_shared PTEs shared",
-				    p, 1,  true);
+				    p, 1, ops, true);
 		}
 
 		validate_memory(p, 0, hpage_pmd_size);
-		munmap(p, hpage_pmd_size);
+		ops->cleanup_area(p, hpage_pmd_size);
 		exit(exit_status);
 	}
 
@@ -959,42 +1014,28 @@ static void collapse_max_ptes_shared(struct collapse_context *c)
 	exit_status += WEXITSTATUS(wstatus);
 
 	printf("Check if parent still has huge page...");
-	if (check_huge(p, 1))
+	if (ops->check_huge(p, 1))
 		success("OK");
 	else
 		fail("Fail");
 	validate_memory(p, 0, hpage_pmd_size);
-	munmap(p, hpage_pmd_size);
+	ops->cleanup_area(p, hpage_pmd_size);
 }
 
-static void madvise_collapse_existing_thps(void)
+static void madvise_collapse_existing_thps(struct collapse_context *c,
+					   struct mem_ops *ops)
 {
 	void *p;
-	int err;
 
-	p = alloc_mapping(1);
-	fill_memory(p, 0, hpage_pmd_size);
+	p = ops->setup_area(1);
+	ops->fault(p, 0, hpage_pmd_size);
+	c->collapse("Collapse fully populated PTE table...", p, 1, ops, true);
+	validate_memory(p, 0, hpage_pmd_size);
 
-	printf("Collapse fully populated PTE table...");
-	/*
-	 * Note that we don't set MADV_HUGEPAGE here, which
-	 * also tests that VM_HUGEPAGE isn't required for
-	 * MADV_COLLAPSE in "madvise" mode.
-	 */
-	err = madvise(p, hpage_pmd_size, MADV_COLLAPSE);
-	if (err == 0 && check_huge(p, 1)) {
-		success("OK");
-		printf("Re-collapse PMD-mapped hugepage");
-		err = madvise(p, hpage_pmd_size, MADV_COLLAPSE);
-		if (err == 0 && check_huge(p, 1))
-			success("OK");
-		else
-			fail("Fail");
-	} else {
-		fail("Fail");
-	}
+	/* c->collapse() will find a hugepage and complain - call directly. */
+	__madvise_collapse("Re-collapse PMD-mapped hugepage", p, 1, ops, true);
 	validate_memory(p, 0, hpage_pmd_size);
-	munmap(p, hpage_pmd_size);
+	ops->cleanup_area(p, hpage_pmd_size);
 }
 
 int main(int argc, const char **argv)
@@ -1034,37 +1075,37 @@ int main(int argc, const char **argv)
 		c.collapse = &khugepaged_collapse;
 		c.enforce_pte_scan_limits = true;
 
-		collapse_full(&c);
-		collapse_empty(&c);
-		collapse_single_pte_entry(&c);
-		collapse_max_ptes_none(&c);
-		collapse_swapin_single_pte(&c);
-		collapse_max_ptes_swap(&c);
-		collapse_single_pte_entry_compound(&c);
-		collapse_full_of_compound(&c);
-		collapse_compound_extreme(&c);
-		collapse_fork(&c);
-		collapse_fork_compound(&c);
-		collapse_max_ptes_shared(&c);
+		collapse_full(&c, &anon_ops);
+		collapse_empty(&c, &anon_ops);
+		collapse_single_pte_entry(&c, &anon_ops);
+		collapse_max_ptes_none(&c, &anon_ops);
+		collapse_swapin_single_pte(&c, &anon_ops);
+		collapse_max_ptes_swap(&c, &anon_ops);
+		collapse_single_pte_entry_compound(&c, &anon_ops);
+		collapse_full_of_compound(&c, &anon_ops);
+		collapse_compound_extreme(&c, &anon_ops);
+		collapse_fork(&c, &anon_ops);
+		collapse_fork_compound(&c, &anon_ops);
+		collapse_max_ptes_shared(&c, &anon_ops);
 	}
 	if (!strcmp(tests, "madvise") || !strcmp(tests, "all")) {
 		printf("\n*** Testing context: madvise ***\n");
 		c.collapse = &madvise_collapse;
 		c.enforce_pte_scan_limits = false;
 
-		collapse_full(&c);
-		collapse_empty(&c);
-		collapse_single_pte_entry(&c);
-		collapse_max_ptes_none(&c);
-		collapse_swapin_single_pte(&c);
-		collapse_max_ptes_swap(&c);
-		collapse_single_pte_entry_compound(&c);
-		collapse_full_of_compound(&c);
-		collapse_compound_extreme(&c);
-		collapse_fork(&c);
-		collapse_fork_compound(&c);
-		collapse_max_ptes_shared(&c);
-		madvise_collapse_existing_thps();
+		collapse_full(&c, &anon_ops);
+		collapse_empty(&c, &anon_ops);
+		collapse_single_pte_entry(&c, &anon_ops);
+		collapse_max_ptes_none(&c, &anon_ops);
+		collapse_swapin_single_pte(&c, &anon_ops);
+		collapse_max_ptes_swap(&c, &anon_ops);
+		collapse_single_pte_entry_compound(&c, &anon_ops);
+		collapse_full_of_compound(&c, &anon_ops);
+		collapse_compound_extreme(&c, &anon_ops);
+		collapse_fork(&c, &anon_ops);
+		collapse_fork_compound(&c, &anon_ops);
+		collapse_max_ptes_shared(&c, &anon_ops);
+		madvise_collapse_existing_thps(&c, &anon_ops);
 	}
 
 	restore_settings(0);