by Muhammad Usama Anjum

[permalink] [raw]

Subject: Re: [RFC PATCH v3 8/8] mm: test system-wide workingset reporting

Please add selftest tag in the subject in selftest patches.

On 3/28/24 2:31 AM, Yuanchu Xie wrote:
> A basic test that verifies the working set size of a simple memory
> accessor. It should work with or without the aging thread.
>
> Question: I don't know how to best test file memory in selftests. Is
> there a place where I should put the temporary file? /tmp can be tmpfs
> mounted in many distros.
>
> Signed-off-by: Yuanchu Xie <[email protected]>
Thanks for writing most of the test in TAP compliant format. Only replace
printing directly to strerr to ksft_exit_fail_msg() instead.

> ---
> tools/testing/selftests/mm/.gitignore | 1 +
> tools/testing/selftests/mm/Makefile | 3 +
> .../testing/selftests/mm/workingset_report.c | 315 +++++++++++++++++
> .../testing/selftests/mm/workingset_report.h | 37 ++
> .../selftests/mm/workingset_report_test.c | 328 ++++++++++++++++++
> 5 files changed, 684 insertions(+)
> create mode 100644 tools/testing/selftests/mm/workingset_report.c
> create mode 100644 tools/testing/selftests/mm/workingset_report.h
> create mode 100644 tools/testing/selftests/mm/workingset_report_test.c
>
> diff --git a/tools/testing/selftests/mm/.gitignore b/tools/testing/selftests/mm/.gitignore
> index 4ff10ea61461..14a2412c8257 100644
> --- a/tools/testing/selftests/mm/.gitignore
> +++ b/tools/testing/selftests/mm/.gitignore
> @@ -46,3 +46,4 @@ gup_longterm
> mkdirty
> va_high_addr_switch
> hugetlb_fault_after_madv
> +workingset_report_test
> diff --git a/tools/testing/selftests/mm/Makefile b/tools/testing/selftests/mm/Makefile
> index 2453add65d12..c0869bf07e99 100644
> --- a/tools/testing/selftests/mm/Makefile
> +++ b/tools/testing/selftests/mm/Makefile
> @@ -70,6 +70,7 @@ TEST_GEN_FILES += ksm_tests
> TEST_GEN_FILES += ksm_functional_tests
> TEST_GEN_FILES += mdwe_test
> TEST_GEN_FILES += hugetlb_fault_after_madv
> +TEST_GEN_FILES += workingset_report_test
>
> ifneq ($(ARCH),arm64)
> TEST_GEN_FILES += soft-dirty
> @@ -123,6 +124,8 @@ $(TEST_GEN_FILES): vm_util.c thp_settings.c
> $(OUTPUT)/uffd-stress: uffd-common.c
> $(OUTPUT)/uffd-unit-tests: uffd-common.c
>
> +$(OUTPUT)/workingset_report_test: workingset_report.c
> +
> ifeq ($(ARCH),x86_64)
> BINARIES_32 := $(patsubst %,$(OUTPUT)/%,$(BINARIES_32))
> BINARIES_64 := $(patsubst %,$(OUTPUT)/%,$(BINARIES_64))
> diff --git a/tools/testing/selftests/mm/workingset_report.c b/tools/testing/selftests/mm/workingset_report.c
> new file mode 100644
> index 000000000000..93387f0f30ee
> --- /dev/null
> +++ b/tools/testing/selftests/mm/workingset_report.c
> @@ -0,0 +1,315 @@
> +// SPDX-License-Identifier: GPL-2.0
> +#include "workingset_report.h"
> +
> +#include <stddef.h>
> +#include <stdlib.h>
> +#include <stdio.h>
> +#include <stdbool.h>
> +#include <unistd.h>
> +#include <string.h>
> +#include <sys/mman.h>
> +#include <sys/wait.h>
> +
> +#define SYSFS_NODE_ONLINE "/sys/devices/system/node/online"
> +#define PROC_DROP_CACHES "/proc/sys/vm/drop_caches"
> +
> +/* Returns read len on success, or -errno on failure. */
> +static ssize_t read_text(const char *path, char *buf, size_t max_len)
> +{
> + ssize_t len;
> + int fd, err;
> + size_t bytes_read = 0;
> +
> + if (!max_len)
> + return -EINVAL;
> +
> + fd = open(path, O_RDONLY);
> + if (fd < 0)
> + return -errno;
> +
> + while (bytes_read < max_len - 1) {
> + len = read(fd, buf + bytes_read, max_len - 1 - bytes_read);
> +
> + if (len <= 0)
> + break;
> + bytes_read += len;
> + }
> +
> + buf[bytes_read] = '\0';
> +
> + err = -errno;
> + close(fd);
> + return len < 0 ? err : bytes_read;
> +}
> +
> +/* Returns written len on success, or -errno on failure. */
> +static ssize_t write_text(const char *path, const char *buf, ssize_t max_len)
> +{
> + int fd, len, err;
> + size_t bytes_written = 0;
> +
> + fd = open(path, O_WRONLY | O_APPEND);
> + if (fd < 0)
> + return -errno;
> +
> + while (bytes_written < max_len) {
> + len = write(fd, buf + bytes_written, max_len - bytes_written);
> +
> + if (len < 0)
> + break;
> + bytes_written += len;
> + }
> +
> + err = -errno;
> + close(fd);
> + return len < 0 ? err : bytes_written;
> +}
> +
> +static long read_num(const char *path)
> +{
> + char buf[21];
> +
> + if (read_text(path, buf, sizeof(buf)) <= 0)
> + return -1;
> + return (long)strtoul(buf, NULL, 10);
> +}
> +
> +static int write_num(const char *path, unsigned long n)
> +{
> + char buf[21];
> +
> + sprintf(buf, "%lu", n);
> + if (write_text(path, buf, strlen(buf)) < 0)
> + return -1;
> + return 0;
> +}
> +
> +long sysfs_get_refresh_interval(int nid)
> +{
> + char file[128];
> +
> + snprintf(
> + file,
> + sizeof(file),
> + "/sys/devices/system/node/node%d/workingset_report/refresh_interval",
> + nid);
> + return read_num(file);
> +}
> +
> +int sysfs_set_refresh_interval(int nid, long interval)
> +{
> + char file[128];
> +
> + snprintf(
> + file,
> + sizeof(file),
> + "/sys/devices/system/node/node%d/workingset_report/refresh_interval",
> + nid);
> + return write_num(file, interval);
> +}
> +
> +int sysfs_get_page_age_intervals_str(int nid, char *buf, int len)
> +{
> + char path[128];
> +
> + snprintf(
> + path,
> + sizeof(path),
> + "/sys/devices/system/node/node%d/workingset_report/page_age_intervals",
> + nid);
> + return read_text(path, buf, len);
> +
> +}
> +
> +int sysfs_set_page_age_intervals_str(int nid, const char *buf, int len)
> +{
> + char path[128];
> +
> + snprintf(
> + path,
> + sizeof(path),
> + "/sys/devices/system/node/node%d/workingset_report/page_age_intervals",
> + nid);
> + return write_text(path, buf, len);
> +}
> +
> +int sysfs_set_page_age_intervals(int nid, const char *intervals[],
> + int nr_intervals)
> +{
> + char file[128];
> + char buf[1024];
> + int i;
> + int err, len = 0;
> +
> + for (i = 0; i < nr_intervals; ++i) {
> + err = snprintf(buf + len, sizeof(buf) - len, "%s", intervals[i]);
> +
> + if (err < 0)
> + return err;
> + len += err;
> +
> + if (i < nr_intervals - 1) {
> + err = snprintf(buf + len, sizeof(buf) - len, ",");
> + if (err < 0)
> + return err;
> + len += err;
> + }
> + }
> +
> + snprintf(
> + file,
> + sizeof(file),
> + "/sys/devices/system/node/node%d/workingset_report/page_age_intervals",
> + nid);
> + return write_text(file, buf, len);
> +}
> +
> +int get_nr_nodes(void)
> +{
> + char buf[22];
> + char *found;
> +
> + if (read_text(SYSFS_NODE_ONLINE, buf, sizeof(buf)) <= 0)
> + return -1;
> + found = strstr(buf, "-");
> + if (found)
> + return (int)strtoul(found + 1, NULL, 10) + 1;
> + return (long)strtoul(buf, NULL, 10) + 1;
> +}
> +
> +int drop_pagecache(void)
> +{
> + return write_num(PROC_DROP_CACHES, 1);
> +}
> +
> +ssize_t sysfs_page_age_read(int nid, char *buf, size_t len)
> +
> +{
> + char file[128];
> +
> + snprintf(file,
> + sizeof(file),
> + "/sys/devices/system/node/node%d/workingset_report/page_age",
> + nid);
> + return read_text(file, buf, len);
> +}
> +
> +/*
> + * Finds the first occurrence of "N<nid>\n"
> + * Modifies buf to terminate before the next occurrence of "N".
> + * Returns a substring of buf starting after "N<nid>\n"
> + */
> +char *page_age_split_node(char *buf, int nid, char **next)
> +{
> + char node_str[5];
> + char *found;
> + int node_str_len;
> +
> + node_str_len = snprintf(node_str, sizeof(node_str), "N%u\n", nid);
> +
> + /* find the node prefix first */
> + found = strstr(buf, node_str);
> + if (!found) {
> + fprintf(stderr, "cannot find '%s' in page_idle_age", node_str);
> + return NULL;
> + }
> + found += node_str_len;
> +
> + *next = strchr(found, 'N');
> + if (*next)
> + *(*next - 1) = '\0';
> +
> + return found;
> +}
> +
> +ssize_t page_age_read(const char *buf, const char *interval, int pagetype)
> +{
> + static const char * const type[ANON_AND_FILE] = { "anon=", "file=" };
> + char *found;
> +
> + found = strstr(buf, interval);
> + if (!found) {
> + fprintf(stderr, "cannot find %s in page_age", interval);
> + return -1;
> + }
> + found = strstr(found, type[pagetype]);
> + if (!found) {
> + fprintf(stderr, "cannot find %s in page_age", type[pagetype]);
> + return -1;
> + }
> + found += strlen(type[pagetype]);
> + return (long)strtoul(found, NULL, 10);
> +}
> +
> +static const char *TEMP_FILE = "/tmp/workingset_selftest";
> +void cleanup_file_workingset(void)
> +{
> + remove(TEMP_FILE);
> +}
> +
> +int alloc_file_workingset(void *arg)
> +{
> + int err = 0;
> + char *ptr;
> + int fd;
> + int ppid;
> + char *mapped;
> + size_t size = (size_t)arg;
> + size_t page_size = getpagesize();
> +
> + ppid = getppid();
> +
> + fd = open(TEMP_FILE, O_RDWR | O_CREAT);
> + if (fd < 0) {
> + err = -errno;
> + perror("failed to open temp file\n");
> + goto cleanup;
> + }
> +
> + if (fallocate(fd, 0, 0, size) < 0) {
> + err = -errno;
> + perror("fallocate");
> + goto cleanup;
> + }
> +
> + mapped = (char *)mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED,
> + fd, 0);
> + if (mapped == NULL) {
> + err = -errno;
> + perror("mmap");
> + goto cleanup;
> + }
> +
> + while (getppid() == ppid) {
> + sync();
> + for (ptr = mapped; ptr < mapped + size; ptr += page_size)
> + *ptr = *ptr ^ 0xFF;
> + }
> +
> +cleanup:
> + cleanup_file_workingset();
> + return err;
> +}
> +
> +int alloc_anon_workingset(void *arg)
> +{
> + char *buf, *ptr;
> + int ppid = getppid();
> + size_t size = (size_t)arg;
> + size_t page_size = getpagesize();
> +
> + buf = malloc(size);
> +
> + if (!buf) {
> + fprintf(stderr, "cannot allocate anon workingset");
> + exit(1);
> + }
> +
> + while (getppid() == ppid) {
> + for (ptr = buf; ptr < buf + size; ptr += page_size)
> + *ptr = *ptr ^ 0xFF;
> + }
> +
> + free(buf);
> + return 0;
> +}
> diff --git a/tools/testing/selftests/mm/workingset_report.h b/tools/testing/selftests/mm/workingset_report.h
> new file mode 100644
> index 000000000000..f72a931298e0
> --- /dev/null
> +++ b/tools/testing/selftests/mm/workingset_report.h
> @@ -0,0 +1,37 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef WORKINGSET_REPORT_H_
> +#define WORKINGSET_REPORT_H_
> +
> +#define _GNU_SOURCE
> +
> +#include <fcntl.h>
> +#include <sys/stat.h>
> +#include <errno.h>
> +#include <stdint.h>
> +#include <sys/types.h>
> +
> +#define PAGETYPE_ANON 0
> +#define PAGETYPE_FILE 1
> +#define ANON_AND_FILE 2
> +
> +int get_nr_nodes(void);
> +int drop_pagecache(void);
> +
> +long sysfs_get_refresh_interval(int nid);
> +int sysfs_set_refresh_interval(int nid, long interval);
> +
> +int sysfs_get_page_age_intervals_str(int nid, char *buf, int len);
> +int sysfs_set_page_age_intervals_str(int nid, const char *buf, int len);
> +
> +int sysfs_set_page_age_intervals(int nid, const char *intervals[],
> + int nr_intervals);
> +
> +char *page_age_split_node(char *buf, int nid, char **next);
> +ssize_t sysfs_page_age_read(int nid, char *buf, size_t len);
> +ssize_t page_age_read(const char *buf, const char *interval, int pagetype);
> +
> +int alloc_file_workingset(void *arg);
> +void cleanup_file_workingset(void);
> +int alloc_anon_workingset(void *arg);
> +
> +#endif /* WORKINGSET_REPORT_H_ */
> diff --git a/tools/testing/selftests/mm/workingset_report_test.c b/tools/testing/selftests/mm/workingset_report_test.c
> new file mode 100644
> index 000000000000..e6e857d8fe35
> --- /dev/null
> +++ b/tools/testing/selftests/mm/workingset_report_test.c
> @@ -0,0 +1,328 @@
> +// SPDX-License-Identifier: GPL-2.0
> +#include "workingset_report.h"
> +
> +#include <stdlib.h>
> +#include <stdio.h>
> +#include <signal.h>
> +#include <time.h>
> +
> +#include "../clone3/clone3_selftests.h"
> +
> +#define REFRESH_INTERVAL 5000
> +#define MB(x) (x << 20)
> +
> +static void sleep_ms(int milliseconds)
> +{
> + struct timespec ts;
> +
> + ts.tv_sec = milliseconds / 1000;
> + ts.tv_nsec = (milliseconds % 1000) * 1000000;
> + nanosleep(&ts, NULL);
> +}
> +
> +/*
> + * Checks if two given values differ by less than err% of their sum.
> + */
> +static inline int values_close(long a, long b, int err)
> +{
> + return abs(a - b) <= (a + b) / 100 * err;
> +}
> +
> +static const char * const PAGE_AGE_INTERVALS[] = {
> + "6000", "10000", "15000", "18446744073709551615",
> +};
> +#define NR_PAGE_AGE_INTERVALS (ARRAY_SIZE(PAGE_AGE_INTERVALS))
> +/* add one for the catch all last interval */
> +
> +static int set_page_age_intervals_all_nodes(const char *intervals, int nr_nodes)
> +{
> + int i;
> +
> + for (i = 0; i < nr_nodes; ++i) {
> + int err = sysfs_set_page_age_intervals_str(
> + i, &intervals[i * 1024], strlen(&intervals[i * 1024]));
> +
> + if (err < 0)
> + return err;
> + }
> + return 0;
> +}
> +
> +static int get_page_age_intervals_all_nodes(char *intervals, int nr_nodes)
> +{
> + int i;
> +
> + for (i = 0; i < nr_nodes; ++i) {
> + int err = sysfs_get_page_age_intervals_str(
> + i, &intervals[i * 1024], 1024);
> +
> + if (err < 0)
> + return err;
> + }
> + return 0;
> +}
> +
> +static int set_refresh_interval_all_nodes(const long *interval, int nr_nodes)
> +{
> + int i;
> +
> + for (i = 0; i < nr_nodes; ++i) {
> + int err = sysfs_set_refresh_interval(i, interval[i]);
> +
> + if (err < 0)
> + return err;
> + }
> + return 0;
> +}
> +
> +static int get_refresh_interval_all_nodes(long *interval, int nr_nodes)
> +{
> + int i;
> +
> + for (i = 0; i < nr_nodes; ++i) {
> + long val = sysfs_get_refresh_interval(i);
> +
> + if (val < 0)
> + return val;
> + interval[i] = val;
> + }
> + return 0;
> +}
> +
> +static pid_t clone_and_run(int fn(void *arg), void *arg)
> +{
> + pid_t pid;
> +
> + struct __clone_args args = {
> + .exit_signal = SIGCHLD,
> + };
> +
> + pid = sys_clone3(&args, sizeof(struct __clone_args));
> +
> + if (pid == 0)
> + exit(fn(arg));
> +
> + return pid;
> +}
> +
> +static int read_workingset(int pagetype, int nid,
> + unsigned long page_age[NR_PAGE_AGE_INTERVALS])
> +{
> + int i, err;
> + char buf[4096];
> +
> + err = sysfs_page_age_read(nid, buf, sizeof(buf));
> + if (err < 0)
> + return err;
> +
> + for (i = 0; i < NR_PAGE_AGE_INTERVALS; ++i) {
> + err = page_age_read(buf, PAGE_AGE_INTERVALS[i], pagetype);
> + if (err < 0)
> + return err;
> + page_age[i] = err;
> + }
> +
> + return 0;
> +}
> +
> +static ssize_t read_interval_all_nodes(int pagetype, int interval)
> +{
> + int i, err;
> + unsigned long page_age[NR_PAGE_AGE_INTERVALS];
> + ssize_t ret = 0;
> + int nr_nodes = get_nr_nodes();
> +
> + for (i = 0; i < nr_nodes; ++i) {
> + err = read_workingset(pagetype, i, page_age);
> + if (err < 0)
> + return err;
> +
> + ret += page_age[interval];
> + }
> +
> + return ret;
> +}
> +
> +#define TEST_SIZE MB(500l)
> +
> +static int run_test(int f(void))
> +{
> + int i, err, test_result;
> + long *old_refresh_intervals;
> + long *new_refresh_intervals;
> + char *old_page_age_intervals;
> + int nr_nodes = get_nr_nodes();
> +
> + if (nr_nodes <= 0) {
> + fprintf(stderr, "failed to get nr_nodes\n");
> + return KSFT_FAIL;
> + }
> +
> + old_refresh_intervals = calloc(nr_nodes, sizeof(long));
> + new_refresh_intervals = calloc(nr_nodes, sizeof(long));
> + old_page_age_intervals = calloc(nr_nodes, 1024);
> +
> + if (!(old_refresh_intervals && new_refresh_intervals &&
> + old_page_age_intervals)) {
> + fprintf(stderr, "failed to allocate memory for intervals\n");
> + return KSFT_FAIL;
> + }
> +
> + err = get_refresh_interval_all_nodes(old_refresh_intervals, nr_nodes);
> + if (err < 0) {
> + fprintf(stderr, "failed to read refresh interval\n");
> + return KSFT_FAIL;
> + }
> +
> + err = get_page_age_intervals_all_nodes(old_page_age_intervals, nr_nodes);
> + if (err < 0) {
> + fprintf(stderr, "failed to read page age interval\n");
> + return KSFT_FAIL;
> + }
> +
> + for (i = 0; i < nr_nodes; ++i)
> + new_refresh_intervals[i] = REFRESH_INTERVAL;
> + err = set_refresh_interval_all_nodes(new_refresh_intervals, nr_nodes);
> + if (err < 0) {
> + fprintf(stderr, "failed to set refresh interval\n");
> + test_result = KSFT_FAIL;
> + goto fail;
> + }
> +
> + for (i = 0; i < nr_nodes; ++i) {
> + err = sysfs_set_page_age_intervals(i, PAGE_AGE_INTERVALS,
> + NR_PAGE_AGE_INTERVALS - 1);
> + if (err < 0) {
> + fprintf(stderr, "failed to set page age interval\n");
> + test_result = KSFT_FAIL;
> + goto fail;
> + }
> + }
> +
> + sync();
> + drop_pagecache();
> +
> + test_result = f();
> +
> +fail:
> + err = set_refresh_interval_all_nodes(old_refresh_intervals, nr_nodes);
> + if (err < 0) {
> + fprintf(stderr, "failed to restore refresh interval\n");
> + test_result = KSFT_FAIL;
> + }
> + err = set_page_age_intervals_all_nodes(old_page_age_intervals, nr_nodes);
> + if (err < 0) {
> + fprintf(stderr, "failed to restore page age interval\n");
> + test_result = KSFT_FAIL;
> + }
> + return test_result;
> +}
> +
> +static int test_file(void)
> +{
> + ssize_t ws_size_ref, ws_size_test;
> + int ret = KSFT_FAIL, i;
> + pid_t pid = 0;
> +
> + ws_size_ref = read_interval_all_nodes(PAGETYPE_FILE, 0);
> + if (ws_size_ref < 0)
> + goto cleanup;
> +
> + pid = clone_and_run(alloc_file_workingset, (void *)TEST_SIZE);
> + if (pid < 0)
> + goto cleanup;
> +
> + read_interval_all_nodes(PAGETYPE_FILE, 0);
> + sleep_ms(REFRESH_INTERVAL);
> +
> + for (i = 0; i < 3; ++i) {
> + sleep_ms(REFRESH_INTERVAL);
> + ws_size_test = read_interval_all_nodes(PAGETYPE_FILE, 0);
> +
> + if (!values_close(ws_size_test - ws_size_ref, TEST_SIZE, 10)) {
> + fprintf(stderr,
> + "file working set size difference too large: actual=%ld, expected=%ld\n",
> + ws_size_test - ws_size_ref, TEST_SIZE);
> + goto cleanup;
> + }
> + }
> + ret = KSFT_PASS;
> +
> +cleanup:
> + if (pid > 0)
> + kill(pid, SIGKILL);
> + cleanup_file_workingset();
> + return ret;
> +}
> +
> +static int test_anon(void)
> +{
> + ssize_t ws_size_ref, ws_size_test;
> + pid_t pid = 0;
> + int ret = KSFT_FAIL, i;
> +
> + ws_size_ref = read_interval_all_nodes(PAGETYPE_ANON, 0);
> + if (ws_size_ref < 0)
> + goto cleanup;
> +
> + pid = clone_and_run(alloc_anon_workingset, (void *)TEST_SIZE);
> + if (pid < 0)
> + goto cleanup;
> +
> + sleep_ms(REFRESH_INTERVAL);
> + read_interval_all_nodes(PAGETYPE_ANON, 0);
> +
> + for (i = 0; i < 5; ++i) {
> + sleep_ms(REFRESH_INTERVAL);
> + ws_size_test = read_interval_all_nodes(PAGETYPE_ANON, 0);
> + if (ws_size_test < 0)
> + goto cleanup;
> +
> + if (!values_close(ws_size_test - ws_size_ref, TEST_SIZE, 10)) {
> + fprintf(stderr,
> + "anon working set size difference too large: actual=%ld, expected=%ld\n",
> + ws_size_test - ws_size_ref, TEST_SIZE);
> + /* goto cleanup; */
> + }
> + }
> + ret = KSFT_PASS;
> +
> +cleanup:
> + if (pid > 0)
> + kill(pid, SIGKILL);
> + return ret;
> +}
> +
> +
> +#define T(x) { x, #x }
> +struct workingset_test {
> + int (*fn)(void);
> + const char *name;
> +} tests[] = {
> + T(test_anon),
> + T(test_file),
> +};
> +#undef T
> +
> +int main(int argc, char **argv)
> +{
> + int ret = EXIT_SUCCESS, i, err;
> +
> + for (i = 0; i < ARRAY_SIZE(tests); i++) {
> + err = run_test(tests[i].fn);
> + switch (err) {
> + case KSFT_PASS:
> + ksft_test_result_pass("%s\n", tests[i].name);
> + break;
> + case KSFT_SKIP:
> + ksft_test_result_skip("%s\n", tests[i].name);
> + break;
> + default:
> + ret = EXIT_FAILURE;
> + ksft_test_result_fail("%s with error %d\n",
> + tests[i].name, err);
> + break;
> + }
> + }
> + return ret;
> +}

--
BR,
Muhammad Usama Anjum