The patch titled Subject: selftests/mm: add new selftests for KSM has been added to the -mm mm-unstable branch. Its filename is selftests-mm-add-new-selftests-for-ksm.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/selftests-mm-add-new-selftests-for-ksm.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Stefan Roesch <shr@xxxxxxxxxxxx> Subject: selftests/mm: add new selftests for KSM Date: Mon, 17 Apr 2023 22:13:42 -0700 This adds three new tests to the selftests for KSM. These tests use the new prctl API's to enable and disable KSM. 1) add new prctl flags to prctl header file in tools dir This adds the new prctl flags to the include file prct.h in the tools directory. This makes sure they are available for testing. 2) add KSM prctl merge test to ksm_tests 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. 3) add two functions for debugging merge outcome for ksm_tests This adds two functions to report the metrics in /proc/self/ksm_stat and /sys/kernel/debug/mm/ksm. The debug output is enabled with the -d option. 4) add KSM prctl test to ksm_functional_tests This adds a test to the ksm_functional_test that verifies that the prctl system call to enable / disable KSM works. 5) add KSM fork test to ksm_functional_test Add fork test to verify that the MMF_VM_MERGE_ANY flag is inherited by the child process. Link: https://lkml.kernel.org/r/20230418051342.1919757-4-shr@xxxxxxxxxxxx Signed-off-by: Stefan Roesch <shr@xxxxxxxxxxxx> Acked-by: David Hildenbrand <david@xxxxxxxxxx> Cc: Bagas Sanjaya <bagasdotme@xxxxxxxxx> Cc: David Hildenbrand <david@xxxxxxxxxx> Cc: Johannes Weiner <hannes@xxxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxx> Cc: Rik van Riel <riel@xxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- tools/include/uapi/linux/prctl.h | 2 tools/testing/selftests/mm/Makefile | 2 tools/testing/selftests/mm/ksm_functional_tests.c | 91 ++++++ tools/testing/selftests/mm/ksm_tests.c | 172 +++++++++--- 4 files changed, 228 insertions(+), 39 deletions(-) --- a/tools/include/uapi/linux/prctl.h~selftests-mm-add-new-selftests-for-ksm +++ a/tools/include/uapi/linux/prctl.h @@ -290,4 +290,6 @@ struct prctl_mm_map { #define PR_SET_VMA 0x53564d41 # define PR_SET_VMA_ANON_NAME 0 +#define PR_SET_MEMORY_MERGE 67 +#define PR_GET_MEMORY_MERGE 68 #endif /* _LINUX_PRCTL_H */ --- a/tools/testing/selftests/mm/ksm_functional_tests.c~selftests-mm-add-new-selftests-for-ksm +++ a/tools/testing/selftests/mm/ksm_functional_tests.c @@ -15,8 +15,10 @@ #include <errno.h> #include <fcntl.h> #include <sys/mman.h> +#include <sys/prctl.h> #include <sys/syscall.h> #include <sys/ioctl.h> +#include <sys/wait.h> #include <linux/userfaultfd.h> #include "../kselftest.h" @@ -237,9 +239,93 @@ unmap: } #endif +/* Verify that KSM can be enabled / queried with prctl. */ +static void test_prctl(void) +{ + int ret; + + ksft_print_msg("[RUN] %s\n", __func__); + + ret = prctl(PR_SET_MEMORY_MERGE, 1, 0, 0, 0); + if (ret < 0 && errno == EINVAL) { + ksft_test_result_skip("PR_SET_MEMORY_MERGE not supported\n"); + return; + } else if (ret) { + ksft_test_result_fail("PR_SET_MEMORY_MERGE=1 failed\n"); + return; + } + + ret = prctl(PR_GET_MEMORY_MERGE, 0, 0, 0, 0); + if (ret < 0) { + ksft_test_result_fail("PR_GET_MEMORY_MERGE failed\n"); + return; + } else if (ret != 1) { + ksft_test_result_fail("PR_SET_MEMORY_MERGE=1 not effective\n"); + return; + } + + ret = prctl(PR_SET_MEMORY_MERGE, 0, 0, 0, 0); + if (ret) { + ksft_test_result_fail("PR_SET_MEMORY_MERGE=0 failed\n"); + return; + } + + ret = prctl(PR_GET_MEMORY_MERGE, 0, 0, 0, 0); + if (ret < 0) { + ksft_test_result_fail("PR_GET_MEMORY_MERGE failed\n"); + return; + } else if (ret != 0) { + ksft_test_result_fail("PR_SET_MEMORY_MERGE=0 not effective\n"); + return; + } + + ksft_test_result_pass("Setting/clearing PR_SET_MEMORY_MERGE works\n"); +} + +/* Verify that prctl ksm flag is inherited. */ +static void test_prctl_fork(void) +{ + int ret, status; + pid_t child_pid; + + ksft_print_msg("[RUN] %s\n", __func__); + + ret = prctl(PR_SET_MEMORY_MERGE, 1, 0, 0, 0); + if (ret < 0 && errno == EINVAL) { + ksft_test_result_skip("PR_SET_MEMORY_MERGE not supported\n"); + return; + } else if (ret) { + ksft_test_result_fail("PR_SET_MEMORY_MERGE=1 failed\n"); + return; + } + + child_pid = fork(); + if (!child_pid) { + exit(prctl(PR_GET_MEMORY_MERGE, 0, 0, 0, 0)); + } else if (child_pid < 0) { + ksft_test_result_fail("fork() failed\n"); + return; + } + + if (waitpid(child_pid, &status, 0) < 0) { + ksft_test_result_fail("waitpid() failed\n"); + return; + } else if (WEXITSTATUS(status) != 1) { + ksft_test_result_fail("unexpected PR_GET_MEMORY_MERGE result in child\n"); + return; + } + + if (prctl(PR_SET_MEMORY_MERGE, 0, 0, 0, 0)) { + ksft_test_result_fail("PR_SET_MEMORY_MERGE=0 failed\n"); + return; + } + + ksft_test_result_pass("PR_SET_MEMORY_MERGE value is inherited\n"); +} + int main(int argc, char **argv) { - unsigned int tests = 2; + unsigned int tests = 4; int err; #ifdef __NR_userfaultfd @@ -267,6 +353,9 @@ int main(int argc, char **argv) test_unmerge_uffd_wp(); #endif + test_prctl(); + test_prctl_fork(); + err = ksft_get_fail_cnt(); if (err) ksft_exit_fail_msg("%d out of %d tests failed\n", --- a/tools/testing/selftests/mm/ksm_tests.c~selftests-mm-add-new-selftests-for-ksm +++ a/tools/testing/selftests/mm/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 { @@ -33,9 +36,16 @@ 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, + CHECK_KSM_GET_MERGE_TYPE, CHECK_KSM_ZERO_PAGE_MERGE, CHECK_KSM_NUMA_MERGE, KSM_MERGE_TIME, @@ -44,6 +54,8 @@ enum ksm_test_name { KSM_COW_TIME }; +int debug; + static int ksm_write_sysfs(const char *file_path, unsigned long val) { FILE *f = fopen(file_path, "w"); @@ -82,6 +94,53 @@ static int ksm_read_sysfs(const char *fi return 0; } +static void ksm_print_sysfs(void) +{ + unsigned long max_page_sharing, pages_sharing, pages_shared; + unsigned long full_scans, pages_unshared, pages_volatile; + unsigned long stable_node_chains, stable_node_dups; + long general_profit; + + if (ksm_read_sysfs(KSM_FP("pages_shared"), &pages_shared) || + ksm_read_sysfs(KSM_FP("pages_sharing"), &pages_sharing) || + ksm_read_sysfs(KSM_FP("max_page_sharing"), &max_page_sharing) || + ksm_read_sysfs(KSM_FP("full_scans"), &full_scans) || + ksm_read_sysfs(KSM_FP("pages_unshared"), &pages_unshared) || + ksm_read_sysfs(KSM_FP("pages_volatile"), &pages_volatile) || + ksm_read_sysfs(KSM_FP("stable_node_chains"), &stable_node_chains) || + ksm_read_sysfs(KSM_FP("stable_node_dups"), &stable_node_dups) || + ksm_read_sysfs(KSM_FP("general_profit"), (unsigned long *)&general_profit)) + return; + + printf("pages_shared : %lu\n", pages_shared); + printf("pages_sharing : %lu\n", pages_sharing); + printf("max_page_sharing : %lu\n", max_page_sharing); + printf("full_scans : %lu\n", full_scans); + printf("pages_unshared : %lu\n", pages_unshared); + printf("pages_volatile : %lu\n", pages_volatile); + printf("stable_node_chains: %lu\n", stable_node_chains); + printf("stable_node_dups : %lu\n", stable_node_dups); + printf("general_profit : %ld\n", general_profit); +} + +static void ksm_print_procfs(void) +{ + const char *file_name = "/proc/self/ksm_stat"; + char buffer[512]; + FILE *f = fopen(file_name, "r"); + + if (!f) { + fprintf(stderr, "f %s\n", file_name); + perror("fopen"); + return; + } + + while (fgets(buffer, sizeof(buffer), f)) + printf("%s", buffer); + + fclose(f); +} + static int str_to_prot(char *prot_str) { int prot = 0; @@ -128,7 +187,12 @@ static void print_help(void) " Default: %d\n", KSM_USE_ZERO_PAGES_DEFAULT); printf(" -m: change merge_across_nodes tunable\n" " Default: %d\n", KSM_MERGE_ACROSS_NODES_DEFAULT); + printf(" -d: turn debugging output on\n"); 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 +240,21 @@ static int ksm_do_scan(int scan_count, s 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, 0, 0, 0)) { + perror("prctl"); + return 1; + } } + if (ksm_write_sysfs(KSM_FP("run"), 1)) return 1; @@ -211,6 +284,11 @@ static bool assert_ksm_pages_count(long ksm_read_sysfs(KSM_FP("max_page_sharing"), &max_page_sharing)) return false; + if (debug) { + ksm_print_sysfs(); + ksm_print_procfs(); + } + /* * Since there must be at least 2 pages for merging and 1 page can be * shared with the limited number of pages (max_page_sharing), sometimes @@ -266,7 +344,8 @@ static int ksm_restore(struct 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 +360,15 @@ static int check_ksm_merge(int mapping, 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_PRCTL) + prctl(PR_SET_MEMORY_MERGE, 0, 0, 0, 0); return KSFT_PASS; } @@ -297,7 +378,7 @@ err_out: 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 +394,7 @@ static int check_ksm_unmerge(int mapping 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 +418,8 @@ err_out: 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 +437,7 @@ static int check_ksm_zero_page_merge(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 +483,8 @@ 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 +520,8 @@ static int check_ksm_numa_merge(int mapp 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 +547,8 @@ err_out: 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 +590,7 @@ static int ksm_merge_hugepages_time(int 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 +615,7 @@ err_out: 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 +631,7 @@ static int ksm_merge_time(int mapping, i 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 +656,7 @@ err_out: 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 +671,7 @@ static int ksm_unmerge_time(int mapping, 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 +703,7 @@ err_out: 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 +742,7 @@ static int ksm_cow_time(int mapping, int 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 +779,7 @@ 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 +788,7 @@ 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, "dha:p:l:z:m:s:t:MUZNPCHD")) != -1) { switch (opt) { case 'a': prot = str_to_prot(optarg); @@ -739,12 +822,26 @@ int main(int argc, char *argv[]) else merge_across_nodes = 1; break; + case 'd': + debug = 1; + break; case 's': size_MB = atoi(optarg); if (size_MB <= 0) { 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 = tmp; + } + break; case 'M': break; case 'U': @@ -795,35 +892,36 @@ 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 +929,12 @@ 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; } --- a/tools/testing/selftests/mm/Makefile~selftests-mm-add-new-selftests-for-ksm +++ a/tools/testing/selftests/mm/Makefile @@ -29,7 +29,7 @@ MACHINE ?= $(shell echo $(uname_M) | sed # LDLIBS. MAKEFLAGS += --no-builtin-rules -CFLAGS = -Wall -I $(top_srcdir) $(EXTRA_CFLAGS) $(KHDR_INCLUDES) +CFLAGS = -Wall -I $(top_srcdir) -I $(top_srcdir)/tools/include/uapi $(EXTRA_CFLAGS) $(KHDR_INCLUDES) LDLIBS = -lrt -lpthread TEST_GEN_PROGS = cow _ Patches currently in -mm which might be from shr@xxxxxxxxxxxx are mm-add-new-api-to-enable-ksm-per-process.patch mm-add-new-ksm-process-and-sysfs-knobs.patch selftests-mm-add-new-selftests-for-ksm.patch