Add madvise collapse context to hugepage collapse selftests. This
context is tested with /sys/kernel/mm/transparent_hugepage/enabled set
to "never" in order to avoid unwanted interaction with khugepaged during
testing.
Also, refactor updates to sysfs THP settings using a stack so that the
THP settings from nested callers can be restored.
Signed-off-by: Zach O'Keefe <zokeefe@xxxxxxxxxx>
---
tools/testing/selftests/vm/khugepaged.c | 171 +++++++++++++++++-------
1 file changed, 125 insertions(+), 46 deletions(-)
diff --git a/tools/testing/selftests/vm/khugepaged.c b/tools/testing/selftests/vm/khugepaged.c
index eb6f5bbacff1..780f04440e15 100644
--- a/tools/testing/selftests/vm/khugepaged.c
+++ b/tools/testing/selftests/vm/khugepaged.c
@@ -14,6 +14,9 @@
#ifndef MADV_PAGEOUT
#define MADV_PAGEOUT 21
#endif
+#ifndef MADV_COLLAPSE
+#define MADV_COLLAPSE 25
+#endif
#define BASE_ADDR ((void *)(1UL << 30))
static unsigned long hpage_pmd_size;
@@ -95,18 +98,6 @@ struct settings {
struct khugepaged_settings khugepaged;
};
-static struct settings default_settings = {
- .thp_enabled = THP_MADVISE,
- .thp_defrag = THP_DEFRAG_ALWAYS,
- .shmem_enabled = SHMEM_NEVER,
- .use_zero_page = 0,
- .khugepaged = {
- .defrag = 1,
- .alloc_sleep_millisecs = 10,
- .scan_sleep_millisecs = 10,
- },
-};
-
static struct settings saved_settings;
static bool skip_settings_restore;
@@ -284,6 +275,39 @@ static void write_settings(struct settings *settings)
write_num("khugepaged/pages_to_scan", khugepaged->pages_to_scan);
}
+#define MAX_SETTINGS_DEPTH 4
+static struct settings settings_stack[MAX_SETTINGS_DEPTH];
+static int settings_index;
+
+static struct settings *current_settings(void)
+{
+ if (!settings_index) {
+ printf("Fail: No settings set");
+ exit(EXIT_FAILURE);
+ }
+ return settings_stack + settings_index - 1;
+}
+
+static void push_settings(struct settings *settings)
+{
+ if (settings_index >= MAX_SETTINGS_DEPTH) {
+ printf("Fail: Settings stack exceeded");
+ exit(EXIT_FAILURE);
+ }
+ settings_stack[settings_index++] = *settings;
+ write_settings(current_settings());
+}
+
+static void pop_settings(void)
+{
+ if (settings_index <= 0) {
+ printf("Fail: Settings stack empty");
+ exit(EXIT_FAILURE);
+ }
+ --settings_index;
+ write_settings(current_settings());
+}
+
static void restore_settings(int sig)
{
if (skip_settings_restore)
@@ -327,14 +351,6 @@ static void save_settings(void)
signal(SIGQUIT, restore_settings);
}
-static void adjust_settings(void)
-{
-
- printf("Adjust settings...");
- write_settings(&default_settings);
- success("OK");
-}
-
#define MAX_LINE_LENGTH 500
static bool check_for_pattern(FILE *fp, char *pattern, char *buf)
@@ -493,6 +509,38 @@ static void validate_memory(int *p, unsigned long start, unsigned long end)
}
}
+static void madvise_collapse(const char *msg, char *p, bool expect)
+{
+ int ret;
+ struct settings settings = *current_settings();
+
+ printf("%s...", msg);
+ /* Sanity check */
+ if (check_huge(p)) {
+ printf("Unexpected huge page\n");
+ exit(EXIT_FAILURE);
+ }
+
+ /*
+ * Prevent khugepaged interference and tests that MADV_COLLAPSE
+ * ignores /sys/kernel/mm/transparent_hugepage/enabled
+ */
+ settings.thp_enabled = THP_NEVER;
+ push_settings(&settings);
+
+ /* Clear VM_NOHUGEPAGE */
+ madvise(p, hpage_pmd_size, MADV_HUGEPAGE);
+ ret = madvise(p, hpage_pmd_size, MADV_COLLAPSE);
+ if (((bool)ret) == expect)
+ fail("Fail: Bad return value");
+ else if (check_huge(p) != expect)
+ fail("Fail: check_huge()");
+ else
+ success("OK");
+
+ pop_settings();
+}
+
#define TICK 500000
static bool wait_for_scan(const char *msg, char *p)
{
@@ -542,11 +590,11 @@ static void khugepaged_collapse(const char *msg, char *p, bool expect)
static void alloc_at_fault(void)
{
- struct settings settings = default_settings;
+ struct settings settings = *current_settings();
char *p;
settings.thp_enabled = THP_ALWAYS;
- write_settings(&settings);
+ push_settings(&settings);
p = alloc_mapping();
*p = 1;
@@ -556,7 +604,7 @@ static void alloc_at_fault(void)
else
fail("Fail");
- write_settings(&default_settings);
+ pop_settings();
madvise(p, page_size, MADV_DONTNEED);
printf("Split huge PMD on MADV_DONTNEED...");
@@ -602,11 +650,11 @@ static void collapse_single_pte_entry(struct collapse_context *c)
static void collapse_max_ptes_none(struct collapse_context *c)
{
int max_ptes_none = hpage_pmd_nr / 2;
- struct settings settings = default_settings;
+ struct settings settings = *current_settings();
void *p;
settings.khugepaged.max_ptes_none = max_ptes_none;
- write_settings(&settings);
+ push_settings(&settings);
p = alloc_mapping();
@@ -623,7 +671,7 @@ static void collapse_max_ptes_none(struct collapse_context *c)
}
munmap(p, hpage_pmd_size);
- write_settings(&default_settings);
+ pop_settings();
}
static void collapse_swapin_single_pte(struct collapse_context *c)
@@ -703,7 +751,6 @@ static void collapse_single_pte_entry_compound(struct collapse_context *c)
p = alloc_hpage();
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))
@@ -864,7 +911,7 @@ static void collapse_fork_compound(struct collapse_context *c)
c->collapse("Collapse PTE table full of compound pages in child",
p, true);
write_num("khugepaged/max_ptes_shared",
- default_settings.khugepaged.max_ptes_shared);
+ current_settings()->khugepaged.max_ptes_shared);
validate_memory(p, 0, hpage_pmd_size);
munmap(p, hpage_pmd_size);
@@ -943,9 +990,21 @@ static void collapse_max_ptes_shared(struct collapse_context *c)
munmap(p, hpage_pmd_size);
}
-int main(void)
+int main(int argc, const char **argv)
{
struct collapse_context c;
+ struct settings default_settings = {
+ .thp_enabled = THP_MADVISE,
+ .thp_defrag = THP_DEFRAG_ALWAYS,
+ .shmem_enabled = SHMEM_NEVER,
+ .use_zero_page = 0,
+ .khugepaged = {
+ .defrag = 1,
+ .alloc_sleep_millisecs = 10,
+ .scan_sleep_millisecs = 10,
+ },
+ };
+ const char *tests = argc == 1 ? "all" : argv[1];
setbuf(stdout, NULL);
@@ -959,26 +1018,46 @@ int main(void)
default_settings.khugepaged.pages_to_scan = hpage_pmd_nr * 8;
save_settings();
- adjust_settings();
+ push_settings(&default_settings);
alloc_at_fault();
- printf("\n*** Testing context: khugepaged ***\n");
- 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);
+ if (!strcmp(tests, "khugepaged") || !strcmp(tests, "all")) {
+ printf("\n*** Testing context: khugepaged ***\n");
+ 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);
+ }
+ 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);
+ }
restore_settings(0);
}
--
2.37.0.rc0.161.g10f37bed90-goog
