[RESEND RFC PATCH v1 17/20] selftests/vm: add KSM prctl merge test

From: Stefan Roesch
Date: Mon Jan 23 2023 - 13:05:05 EST

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This adds the -t option to the ksm_tests program. The -t flag allows to
specify if it should use madvise or prctl ksm merging.

Signed-off-by: Stefan Roesch <shr@xxxxxxxxxxxx>
---
tools/testing/selftests/vm/Makefile | 3 +-
tools/testing/selftests/vm/ksm_tests.c | 116 +++++++++++++++++--------
2 files changed, 80 insertions(+), 39 deletions(-)

diff --git a/tools/testing/selftests/vm/Makefile b/tools/testing/selftests/vm/Makefile
index 89c14e41bd43..8a50802d8700 100644
--- a/tools/testing/selftests/vm/Makefile
+++ b/tools/testing/selftests/vm/Makefile
@@ -25,7 +25,8 @@ MACHINE ?= $(shell echo $(uname_M) | sed -e 's/aarch64.*/arm64/' -e 's/ppc64.*/p
# LDLIBS.
MAKEFLAGS += --no-builtin-rules

-CFLAGS = -Wall -I $(top_srcdir) -I $(top_srcdir)/usr/include $(EXTRA_CFLAGS) $(KHDR_INCLUDES)
+CFLAGS = -Wall -I $(top_srcdir)/tools/include/uapi
+CFLAGS += -I $(top_srcdir) -I $(top_srcdir)/usr/include $(EXTRA_CFLAGS) $(KHDR_INCLUDES)
LDLIBS = -lrt -lpthread
TEST_GEN_FILES = cow
TEST_GEN_FILES += compaction_test
diff --git a/tools/testing/selftests/vm/ksm_tests.c b/tools/testing/selftests/vm/ksm_tests.c
index f9eb4d67e0dd..386a0929c8a3 100644
--- a/tools/testing/selftests/vm/ksm_tests.c
+++ b/tools/testing/selftests/vm/ksm_tests.c
@@ -1,6 +1,8 @@
// SPDX-License-Identifier: GPL-2.0

#include <sys/mman.h>
+#include <sys/prctl.h>
+#include <sys/wait.h>
#include <stdbool.h>
#include <time.h>
#include <string.h>
@@ -21,6 +23,7 @@
#define KSM_PROT_STR_DEFAULT "rw"
#define KSM_USE_ZERO_PAGES_DEFAULT false
#define KSM_MERGE_ACROSS_NODES_DEFAULT true
+#define KSM_MERGE_TYPE_DEFAULT 0
#define MB (1ul << 20)

struct ksm_sysfs {
@@ -33,6 +36,12 @@ struct ksm_sysfs {
unsigned long use_zero_pages;
};

+enum ksm_merge_type {
+ KSM_MERGE_MADVISE,
+ KSM_MERGE_PRCTL,
+ KSM_MERGE_LAST = KSM_MERGE_PRCTL
+};
+
enum ksm_test_name {
CHECK_KSM_MERGE,
CHECK_KSM_UNMERGE,
@@ -129,6 +138,10 @@ static void print_help(void)
printf(" -m: change merge_across_nodes tunable\n"
" Default: %d\n", KSM_MERGE_ACROSS_NODES_DEFAULT);
printf(" -s: the size of duplicated memory area (in MiB)\n");
+ printf(" -t: KSM merge type\n"
+ " Default: 0\n"
+ " 0: madvise merging\n"
+ " 1: prctl merging\n");

exit(0);
}
@@ -176,12 +189,21 @@ static int ksm_do_scan(int scan_count, struct timespec start_time, int timeout)
return 0;
}

-static int ksm_merge_pages(void *addr, size_t size, struct timespec start_time, int timeout)
+static int ksm_merge_pages(int merge_type, void *addr, size_t size,
+ struct timespec start_time, int timeout)
{
- if (madvise(addr, size, MADV_MERGEABLE)) {
- perror("madvise");
- return 1;
+ if (merge_type == KSM_MERGE_MADVISE) {
+ if (madvise(addr, size, MADV_MERGEABLE)) {
+ perror("madvise");
+ return 1;
+ }
+ } else if (merge_type == KSM_MERGE_PRCTL) {
+ if (prctl(PR_SET_MEMORY_MERGE, 1)) {
+ perror("prctl");
+ return 1;
+ }
}
+
if (ksm_write_sysfs(KSM_FP("run"), 1))
return 1;

@@ -266,7 +288,8 @@ static int ksm_restore(struct ksm_sysfs *ksm_sysfs)
return 0;
}

-static int check_ksm_merge(int mapping, int prot, long page_count, int timeout, size_t page_size)
+static int check_ksm_merge(int merge_type, int mapping, int prot,
+ long page_count, int timeout, size_t page_size)
{
void *map_ptr;
struct timespec start_time;
@@ -281,13 +304,16 @@ static int check_ksm_merge(int mapping, int prot, long page_count, int timeout,
if (!map_ptr)
return KSFT_FAIL;

- if (ksm_merge_pages(map_ptr, page_size * page_count, start_time, timeout))
+ if (ksm_merge_pages(merge_type, map_ptr, page_size * page_count, start_time, timeout))
goto err_out;

/* verify that the right number of pages are merged */
if (assert_ksm_pages_count(page_count)) {
printf("OK\n");
- munmap(map_ptr, page_size * page_count);
+ if (merge_type == KSM_MERGE_MADVISE)
+ munmap(map_ptr, page_size * page_count);
+ else if (merge_type == KSM_MERGE_PRCTL)
+ prctl(PR_SET_MEMORY_MERGE, 0);
return KSFT_PASS;
}

@@ -297,7 +323,7 @@ static int check_ksm_merge(int mapping, int prot, long page_count, int timeout,
return KSFT_FAIL;
}

-static int check_ksm_unmerge(int mapping, int prot, int timeout, size_t page_size)
+static int check_ksm_unmerge(int merge_type, int mapping, int prot, int timeout, size_t page_size)
{
void *map_ptr;
struct timespec start_time;
@@ -313,7 +339,7 @@ static int check_ksm_unmerge(int mapping, int prot, int timeout, size_t page_siz
if (!map_ptr)
return KSFT_FAIL;

- if (ksm_merge_pages(map_ptr, page_size * page_count, start_time, timeout))
+ if (ksm_merge_pages(merge_type, map_ptr, page_size * page_count, start_time, timeout))
goto err_out;

/* change 1 byte in each of the 2 pages -- KSM must automatically unmerge them */
@@ -337,8 +363,8 @@ static int check_ksm_unmerge(int mapping, int prot, int timeout, size_t page_siz
return KSFT_FAIL;
}

-static int check_ksm_zero_page_merge(int mapping, int prot, long page_count, int timeout,
- bool use_zero_pages, size_t page_size)
+static int check_ksm_zero_page_merge(int merge_type, int mapping, int prot, long page_count,
+ int timeout, bool use_zero_pages, size_t page_size)
{
void *map_ptr;
struct timespec start_time;
@@ -356,7 +382,7 @@ static int check_ksm_zero_page_merge(int mapping, int prot, long page_count, int
if (!map_ptr)
return KSFT_FAIL;

- if (ksm_merge_pages(map_ptr, page_size * page_count, start_time, timeout))
+ if (ksm_merge_pages(merge_type, map_ptr, page_size * page_count, start_time, timeout))
goto err_out;

/*
@@ -402,8 +428,8 @@ static int get_first_mem_node(void)
return get_next_mem_node(numa_max_node());
}

-static int check_ksm_numa_merge(int mapping, int prot, int timeout, bool merge_across_nodes,
- size_t page_size)
+static int check_ksm_numa_merge(int merge_type, int mapping, int prot, int timeout,
+ bool merge_across_nodes, size_t page_size)
{
void *numa1_map_ptr, *numa2_map_ptr;
struct timespec start_time;
@@ -439,8 +465,8 @@ static int check_ksm_numa_merge(int mapping, int prot, int timeout, bool merge_a
memset(numa2_map_ptr, '*', page_size);

/* try to merge the pages */
- if (ksm_merge_pages(numa1_map_ptr, page_size, start_time, timeout) ||
- ksm_merge_pages(numa2_map_ptr, page_size, start_time, timeout))
+ if (ksm_merge_pages(merge_type, numa1_map_ptr, page_size, start_time, timeout) ||
+ ksm_merge_pages(merge_type, numa2_map_ptr, page_size, start_time, timeout))
goto err_out;

/*
@@ -466,7 +492,8 @@ static int check_ksm_numa_merge(int mapping, int prot, int timeout, bool merge_a
return KSFT_FAIL;
}

-static int ksm_merge_hugepages_time(int mapping, int prot, int timeout, size_t map_size)
+static int ksm_merge_hugepages_time(int merge_type, int mapping, int prot,
+ int timeout, size_t map_size)
{
void *map_ptr, *map_ptr_orig;
struct timespec start_time, end_time;
@@ -508,7 +535,7 @@ static int ksm_merge_hugepages_time(int mapping, int prot, int timeout, size_t m
perror("clock_gettime");
goto err_out;
}
- if (ksm_merge_pages(map_ptr, map_size, start_time, timeout))
+ if (ksm_merge_pages(merge_type, map_ptr, map_size, start_time, timeout))
goto err_out;
if (clock_gettime(CLOCK_MONOTONIC_RAW, &end_time)) {
perror("clock_gettime");
@@ -533,7 +560,7 @@ static int ksm_merge_hugepages_time(int mapping, int prot, int timeout, size_t m
return KSFT_FAIL;
}

-static int ksm_merge_time(int mapping, int prot, int timeout, size_t map_size)
+static int ksm_merge_time(int merge_type, int mapping, int prot, int timeout, size_t map_size)
{
void *map_ptr;
struct timespec start_time, end_time;
@@ -549,7 +576,7 @@ static int ksm_merge_time(int mapping, int prot, int timeout, size_t map_size)
perror("clock_gettime");
goto err_out;
}
- if (ksm_merge_pages(map_ptr, map_size, start_time, timeout))
+ if (ksm_merge_pages(merge_type, map_ptr, map_size, start_time, timeout))
goto err_out;
if (clock_gettime(CLOCK_MONOTONIC_RAW, &end_time)) {
perror("clock_gettime");
@@ -574,7 +601,7 @@ static int ksm_merge_time(int mapping, int prot, int timeout, size_t map_size)
return KSFT_FAIL;
}

-static int ksm_unmerge_time(int mapping, int prot, int timeout, size_t map_size)
+static int ksm_unmerge_time(int merge_type, int mapping, int prot, int timeout, size_t map_size)
{
void *map_ptr;
struct timespec start_time, end_time;
@@ -589,7 +616,7 @@ static int ksm_unmerge_time(int mapping, int prot, int timeout, size_t map_size)
perror("clock_gettime");
goto err_out;
}
- if (ksm_merge_pages(map_ptr, map_size, start_time, timeout))
+ if (ksm_merge_pages(merge_type, map_ptr, map_size, start_time, timeout))
goto err_out;

if (clock_gettime(CLOCK_MONOTONIC_RAW, &start_time)) {
@@ -621,7 +648,7 @@ static int ksm_unmerge_time(int mapping, int prot, int timeout, size_t map_size)
return KSFT_FAIL;
}

-static int ksm_cow_time(int mapping, int prot, int timeout, size_t page_size)
+static int ksm_cow_time(int merge_type, int mapping, int prot, int timeout, size_t page_size)
{
void *map_ptr;
struct timespec start_time, end_time;
@@ -660,7 +687,7 @@ static int ksm_cow_time(int mapping, int prot, int timeout, size_t page_size)
memset(map_ptr + page_size * i, '+', i / 2 + 1);
memset(map_ptr + page_size * (i + 1), '+', i / 2 + 1);
}
- if (ksm_merge_pages(map_ptr, page_size * page_count, start_time, timeout))
+ if (ksm_merge_pages(merge_type, map_ptr, page_size * page_count, start_time, timeout))
goto err_out;

if (clock_gettime(CLOCK_MONOTONIC_RAW, &start_time)) {
@@ -697,6 +724,7 @@ int main(int argc, char *argv[])
int ret, opt;
int prot = 0;
int ksm_scan_limit_sec = KSM_SCAN_LIMIT_SEC_DEFAULT;
+ int merge_type = KSM_MERGE_TYPE_DEFAULT;
long page_count = KSM_PAGE_COUNT_DEFAULT;
size_t page_size = sysconf(_SC_PAGESIZE);
struct ksm_sysfs ksm_sysfs_old;
@@ -705,7 +733,7 @@ int main(int argc, char *argv[])
bool merge_across_nodes = KSM_MERGE_ACROSS_NODES_DEFAULT;
long size_MB = 0;

- while ((opt = getopt(argc, argv, "ha:p:l:z:m:s:MUZNPCHD")) != -1) {
+ while ((opt = getopt(argc, argv, "ha:p:l:z:m:s:t:MUZNPCHD")) != -1) {
switch (opt) {
case 'a':
prot = str_to_prot(optarg);
@@ -745,6 +773,17 @@ int main(int argc, char *argv[])
printf("Size must be greater than 0\n");
return KSFT_FAIL;
}
+ case 't':
+ {
+ int tmp = atoi(optarg);
+
+ if (tmp < 0 || tmp > KSM_MERGE_LAST) {
+ printf("Invalid merge type\n");
+ return KSFT_FAIL;
+ }
+ merge_type = atoi(optarg);
+ }
+ break;
case 'M':
break;
case 'U':
@@ -795,35 +834,36 @@ int main(int argc, char *argv[])

switch (test_name) {
case CHECK_KSM_MERGE:
- ret = check_ksm_merge(MAP_PRIVATE | MAP_ANONYMOUS, prot, page_count,
+ ret = check_ksm_merge(merge_type, MAP_PRIVATE | MAP_ANONYMOUS, prot, page_count,
ksm_scan_limit_sec, page_size);
break;
case CHECK_KSM_UNMERGE:
- ret = check_ksm_unmerge(MAP_PRIVATE | MAP_ANONYMOUS, prot, ksm_scan_limit_sec,
- page_size);
+ ret = check_ksm_unmerge(merge_type, MAP_PRIVATE | MAP_ANONYMOUS, prot,
+ ksm_scan_limit_sec, page_size);
break;
case CHECK_KSM_ZERO_PAGE_MERGE:
- ret = check_ksm_zero_page_merge(MAP_PRIVATE | MAP_ANONYMOUS, prot, page_count,
- ksm_scan_limit_sec, use_zero_pages, page_size);
+ ret = check_ksm_zero_page_merge(merge_type, MAP_PRIVATE | MAP_ANONYMOUS, prot,
+ page_count, ksm_scan_limit_sec, use_zero_pages,
+ page_size);
break;
case CHECK_KSM_NUMA_MERGE:
- ret = check_ksm_numa_merge(MAP_PRIVATE | MAP_ANONYMOUS, prot, ksm_scan_limit_sec,
- merge_across_nodes, page_size);
+ ret = check_ksm_numa_merge(merge_type, MAP_PRIVATE | MAP_ANONYMOUS, prot,
+ ksm_scan_limit_sec, merge_across_nodes, page_size);
break;
case KSM_MERGE_TIME:
if (size_MB == 0) {
printf("Option '-s' is required.\n");
return KSFT_FAIL;
}
- ret = ksm_merge_time(MAP_PRIVATE | MAP_ANONYMOUS, prot, ksm_scan_limit_sec,
- size_MB);
+ ret = ksm_merge_time(merge_type, MAP_PRIVATE | MAP_ANONYMOUS, prot,
+ ksm_scan_limit_sec, size_MB);
break;
case KSM_MERGE_TIME_HUGE_PAGES:
if (size_MB == 0) {
printf("Option '-s' is required.\n");
return KSFT_FAIL;
}
- ret = ksm_merge_hugepages_time(MAP_PRIVATE | MAP_ANONYMOUS, prot,
+ ret = ksm_merge_hugepages_time(merge_type, MAP_PRIVATE | MAP_ANONYMOUS, prot,
ksm_scan_limit_sec, size_MB);
break;
case KSM_UNMERGE_TIME:
@@ -831,12 +871,12 @@ int main(int argc, char *argv[])
printf("Option '-s' is required.\n");
return KSFT_FAIL;
}
- ret = ksm_unmerge_time(MAP_PRIVATE | MAP_ANONYMOUS, prot,
+ ret = ksm_unmerge_time(merge_type, MAP_PRIVATE | MAP_ANONYMOUS, prot,
ksm_scan_limit_sec, size_MB);
break;
case KSM_COW_TIME:
- ret = ksm_cow_time(MAP_PRIVATE | MAP_ANONYMOUS, prot, ksm_scan_limit_sec,
- page_size);
+ ret = ksm_cow_time(merge_type, MAP_PRIVATE | MAP_ANONYMOUS, prot,
+ ksm_scan_limit_sec, page_size);
break;
}

--
2.30.2

Next message: Davidlohr Bueso: "[PATCH 1/2] kernel/hrtimer: Rely on rt_task() for DL tasks too"
Previous message: Stefan Roesch: "[RESEND RFC PATCH v1 02/20] mm: add flag to __ksm_enter"
In reply to: Stefan Roesch: "[RESEND RFC PATCH v1 02/20] mm: add flag to __ksm_enter"
Next in thread: Stefan Roesch: "[RESEND RFC PATCH v1 16/20] tools: add new prctl flags to prctl in tools dir"
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