On Tue, Oct 13, 2020 at 8:54 PM Kalesh Singh <kaleshsingh@xxxxxxxxxx> wrote:
>
Hi kselftest maintainers,
Could someone ACK this mremap test if there isn't any other concern?
Thanks,
Kalesh
> Test mremap on regions of various sizes and alignments and validate
> data after remapping. Also provide total time for remapping
> the region which is useful for performance comparison of the mremap
> optimizations that move pages at the PMD/PUD levels if HAVE_MOVE_PMD
> and/or HAVE_MOVE_PUD are enabled.
>
> Signed-off-by: Kalesh Singh <kaleshsingh@xxxxxxxxxx>
> Reviewed-by: John Hubbard <jhubbard@xxxxxxxxxx>
> Cc: Shuah Khan <shuah@xxxxxxxxxx>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
> ---
> Changes in v2:
> - Reduce test time by only validating a certain threshold of the
> remapped region (4MB by default). The -t flag can be used to
> set a custom threshold in MB or no threshold by passing 0. (-t0).
> mremap time is not provided in stdout for only partially validated
> regions. This time is only applicable for comparison if the entire
> mapped region was faulted in.
> - Use a random pattern for validating the remapped region. The -p
> flag can be used to run the tests with a specified seed for the
> random pattern.
> - Print test configs (threshold_mb and pattern_seed) to stdout.
> - Remove MAKE_SIMPLE_TEST macro.
> - Define named flags instead of 0 / 1.
> - Add comments for destination address' align_mask and offset.
>
> Changes in v3:
> - Remove unused PATTERN_SIZE definition.
> - Make lines 80 cols or less where they don’t need to be longer.
> - Add John Hubbard’s Reviewed-by tag.
>
> tools/testing/selftests/vm/.gitignore | 1 +
> tools/testing/selftests/vm/Makefile | 1 +
> tools/testing/selftests/vm/mremap_test.c | 344 +++++++++++++++++++++++
> tools/testing/selftests/vm/run_vmtests | 11 +
> 4 files changed, 357 insertions(+)
> create mode 100644 tools/testing/selftests/vm/mremap_test.c
>
> diff --git a/tools/testing/selftests/vm/.gitignore b/tools/testing/selftests/vm/.gitignore
> index 849e8226395a..b3a183c36cb5 100644
> --- a/tools/testing/selftests/vm/.gitignore
> +++ b/tools/testing/selftests/vm/.gitignore
> @@ -8,6 +8,7 @@ thuge-gen
> compaction_test
> mlock2-tests
> mremap_dontunmap
> +mremap_test
> on-fault-limit
> transhuge-stress
> protection_keys
> diff --git a/tools/testing/selftests/vm/Makefile b/tools/testing/selftests/vm/Makefile
> index a9026706d597..f044808b45fa 100644
> --- a/tools/testing/selftests/vm/Makefile
> +++ b/tools/testing/selftests/vm/Makefile
> @@ -16,6 +16,7 @@ TEST_GEN_FILES += map_populate
> TEST_GEN_FILES += mlock-random-test
> TEST_GEN_FILES += mlock2-tests
> TEST_GEN_FILES += mremap_dontunmap
> +TEST_GEN_FILES += mremap_test
> TEST_GEN_FILES += on-fault-limit
> TEST_GEN_FILES += thuge-gen
> TEST_GEN_FILES += transhuge-stress
> diff --git a/tools/testing/selftests/vm/mremap_test.c b/tools/testing/selftests/vm/mremap_test.c
> new file mode 100644
> index 000000000000..9c391d016922
> --- /dev/null
> +++ b/tools/testing/selftests/vm/mremap_test.c
> @@ -0,0 +1,344 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright 2020 Google LLC
> + */
> +#define _GNU_SOURCE
> +
> +#include <errno.h>
> +#include <stdlib.h>
> +#include <string.h>
> +#include <sys/mman.h>
> +#include <time.h>
> +
> +#include "../kselftest.h"
> +
> +#define EXPECT_SUCCESS 0
> +#define EXPECT_FAILURE 1
> +#define NON_OVERLAPPING 0
> +#define OVERLAPPING 1
> +#define NS_PER_SEC 1000000000ULL
> +#define VALIDATION_DEFAULT_THRESHOLD 4 /* 4MB */
> +#define VALIDATION_NO_THRESHOLD 0 /* Verify the entire region */
> +
> +#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
> +#define MIN(X, Y) ((X) < (Y) ? (X) : (Y))
> +
> +struct config {
> + unsigned long long src_alignment;
> + unsigned long long dest_alignment;
> + unsigned long long region_size;
> + int overlapping;
> +};
> +
> +struct test {
> + const char *name;
> + struct config config;
> + int expect_failure;
> +};
> +
> +enum {
> + _1KB = 1ULL << 10, /* 1KB -> not page aligned */
> + _4KB = 4ULL << 10,
> + _8KB = 8ULL << 10,
> + _1MB = 1ULL << 20,
> + _2MB = 2ULL << 20,
> + _4MB = 4ULL << 20,
> + _1GB = 1ULL << 30,
> + _2GB = 2ULL << 30,
> + PTE = _4KB,
> + PMD = _2MB,
> + PUD = _1GB,
> +};
> +
> +#define MAKE_TEST(source_align, destination_align, size, \
> + overlaps, should_fail, test_name) \
> +{ \
> + .name = test_name, \
> + .config = { \
> + .src_alignment = source_align, \
> + .dest_alignment = destination_align, \
> + .region_size = size, \
> + .overlapping = overlaps, \
> + }, \
> + .expect_failure = should_fail \
> +}
> +
> +/*
> + * Returns the start address of the mapping on success, else returns
> + * NULL on failure.
> + */
> +static void *get_source_mapping(struct config c)
> +{
> + unsigned long long addr = 0ULL;
> + void *src_addr = NULL;
> +retry:
> + addr += c.src_alignment;
> + src_addr = mmap((void *) addr, c.region_size, PROT_READ | PROT_WRITE,
> + MAP_FIXED | MAP_ANONYMOUS | MAP_SHARED, -1, 0);
> + if (src_addr == MAP_FAILED) {
> + if (errno == EPERM)
> + goto retry;
> + goto error;
> + }
> + /*
> + * Check that the address is aligned to the specified alignment.
> + * Addresses which have alignments that are multiples of that
> + * specified are not considered valid. For instance, 1GB address is
> + * 2MB-aligned, however it will not be considered valid for a
> + * requested alignment of 2MB. This is done to reduce coincidental
> + * alignment in the tests.
> + */
> + if (((unsigned long long) src_addr & (c.src_alignment - 1)) ||
> + !((unsigned long long) src_addr & c.src_alignment))
> + goto retry;
> +
> + if (!src_addr)
> + goto error;
> +
> + return src_addr;
> +error:
> + ksft_print_msg("Failed to map source region: %s\n",
> + strerror(errno));
> + return NULL;
> +}
> +
> +/* Returns the time taken for the remap on success else returns -1. */
> +static long long remap_region(struct config c, unsigned int threshold_mb,
> + char pattern_seed)
> +{
> + void *addr, *src_addr, *dest_addr;
> + unsigned long long i;
> + struct timespec t_start = {0, 0}, t_end = {0, 0};
> + long long start_ns, end_ns, align_mask, ret, offset;
> + unsigned long long threshold;
> +
> + if (threshold_mb == VALIDATION_NO_THRESHOLD)
> + threshold = c.region_size;
> + else
> + threshold = MIN(threshold_mb * _1MB, c.region_size);
> +
> + src_addr = get_source_mapping(c);
> + if (!src_addr) {
> + ret = -1;
> + goto out;
> + }
> +
> + /* Set byte pattern */
> + srand(pattern_seed);
> + for (i = 0; i < threshold; i++)
> + memset((char *) src_addr + i, (char) rand(), 1);
> +
> + /* Mask to zero out lower bits of address for alignment */
> + align_mask = ~(c.dest_alignment - 1);
> + /* Offset of destination address from the end of the source region */
> + offset = (c.overlapping) ? -c.dest_alignment : c.dest_alignment;
> + addr = (void *) (((unsigned long long) src_addr + c.region_size
> + + offset) & align_mask);
> +
> + /* See comment in get_source_mapping() */
> + if (!((unsigned long long) addr & c.dest_alignment))
> + addr = (void *) ((unsigned long long) addr | c.dest_alignment);
> +
> + clock_gettime(CLOCK_MONOTONIC, &t_start);
> + dest_addr = mremap(src_addr, c.region_size, c.region_size,
> + MREMAP_MAYMOVE|MREMAP_FIXED, (char *) addr);
> + clock_gettime(CLOCK_MONOTONIC, &t_end);
> +
> + if (dest_addr == MAP_FAILED) {
> + ksft_print_msg("mremap failed: %s\n", strerror(errno));
> + ret = -1;
> + goto clean_up_src;
> + }
> +
> + /* Verify byte pattern after remapping */
> + srand(pattern_seed);
> + for (i = 0; i < threshold; i++) {
> + char c = (char) rand();
> +
> + if (((char *) dest_addr)[i] != c) {
> + ksft_print_msg("Data after remap doesn't match at offset %d\n",
> + i);
> + ksft_print_msg("Expected: %#x\t Got: %#x\n", c & 0xff,
> + ((char *) dest_addr)[i] & 0xff);
> + ret = -1;
> + goto clean_up_dest;
> + }
> + }
> +
> + start_ns = t_start.tv_sec * NS_PER_SEC + t_start.tv_nsec;
> + end_ns = t_end.tv_sec * NS_PER_SEC + t_end.tv_nsec;
> + ret = end_ns - start_ns;
> +
> +/*
> + * Since the destination address is specified using MREMAP_FIXED, subsequent
> + * mremap will unmap any previous mapping at the address range specified by
> + * dest_addr and region_size. This significantly affects the remap time of
> + * subsequent tests. So we clean up mappings after each test.
> + */
> +clean_up_dest:
> + munmap(dest_addr, c.region_size);
> +clean_up_src:
> + munmap(src_addr, c.region_size);
> +out:
> + return ret;
> +}
> +
> +static void run_mremap_test_case(struct test test_case, int *failures,
> + unsigned int threshold_mb,
> + unsigned int pattern_seed)
> +{
> + long long remap_time = remap_region(test_case.config, threshold_mb,
> + pattern_seed);
> +
> + if (remap_time < 0) {
> + if (test_case.expect_failure)
> + ksft_test_result_pass("%s\n\tExpected mremap failure\n",
> + test_case.name);
> + else {
> + ksft_test_result_fail("%s\n", test_case.name);
> + *failures += 1;
> + }
> + } else {
> + /*
> + * Comparing mremap time is only applicable if entire region
> + * was faulted in.
> + */
> + if (threshold_mb == VALIDATION_NO_THRESHOLD ||
> + test_case.config.region_size <= threshold_mb * _1MB)
> + ksft_test_result_pass("%s\n\tmremap time: %12lldns\n",
> + test_case.name, remap_time);
> + else
> + ksft_test_result_pass("%s\n", test_case.name);
> + }
> +}
> +
> +static void usage(const char *cmd)
> +{
> + fprintf(stderr,
> + "Usage: %s [[-t <threshold_mb>] [-p <pattern_seed>]]\n"
> + "-t\t only validate threshold_mb of the remapped region\n"
> + " \t if 0 is supplied no threshold is used; all tests\n"
> + " \t are run and remapped regions validated fully.\n"
> + " \t The default threshold used is 4MB.\n"
> + "-p\t provide a seed to generate the random pattern for\n"
> + " \t validating the remapped region.\n", cmd);
> +}
> +
> +static int parse_args(int argc, char **argv, unsigned int *threshold_mb,
> + unsigned int *pattern_seed)
> +{
> + const char *optstr = "t:p:";
> + int opt;
> +
> + while ((opt = getopt(argc, argv, optstr)) != -1) {
> + switch (opt) {
> + case 't':
> + *threshold_mb = atoi(optarg);
> + break;
> + case 'p':
> + *pattern_seed = atoi(optarg);
> + break;
> + default:
> + usage(argv[0]);
> + return -1;
> + }
> + }
> +
> + if (optind < argc) {
> + usage(argv[0]);
> + return -1;
> + }
> +
> + return 0;
> +}
> +
> +int main(int argc, char **argv)
> +{
> + int failures = 0;
> + int i, run_perf_tests;
> + unsigned int threshold_mb = VALIDATION_DEFAULT_THRESHOLD;
> + unsigned int pattern_seed;
> + time_t t;
> +
> + pattern_seed = (unsigned int) time(&t);
> +
> + if (parse_args(argc, argv, &threshold_mb, &pattern_seed) < 0)
> + exit(EXIT_FAILURE);
> +
> + ksft_print_msg("Test configs:\n\tthreshold_mb=%u\n\tpattern_seed=%u\n\n",
> + threshold_mb, pattern_seed);
> +
> + struct test test_cases[] = {
> + /* Expected mremap failures */
> + MAKE_TEST(_4KB, _4KB, _4KB, OVERLAPPING, EXPECT_FAILURE,
> + "mremap - Source and Destination Regions Overlapping"),
> + MAKE_TEST(_4KB, _1KB, _4KB, NON_OVERLAPPING, EXPECT_FAILURE,
> + "mremap - Destination Address Misaligned (1KB-aligned)"),
> + MAKE_TEST(_1KB, _4KB, _4KB, NON_OVERLAPPING, EXPECT_FAILURE,
> + "mremap - Source Address Misaligned (1KB-aligned)"),
> +
> + /* Src addr PTE aligned */
> + MAKE_TEST(PTE, PTE, _8KB, NON_OVERLAPPING, EXPECT_SUCCESS,
> + "8KB mremap - Source PTE-aligned, Destination PTE-aligned"),
> +
> + /* Src addr 1MB aligned */
> + MAKE_TEST(_1MB, PTE, _2MB, NON_OVERLAPPING, EXPECT_SUCCESS,
> + "2MB mremap - Source 1MB-aligned, Destination PTE-aligned"),
> + MAKE_TEST(_1MB, _1MB, _2MB, NON_OVERLAPPING, EXPECT_SUCCESS,
> + "2MB mremap - Source 1MB-aligned, Destination 1MB-aligned"),
> +
> + /* Src addr PMD aligned */
> + MAKE_TEST(PMD, PTE, _4MB, NON_OVERLAPPING, EXPECT_SUCCESS,
> + "4MB mremap - Source PMD-aligned, Destination PTE-aligned"),
> + MAKE_TEST(PMD, _1MB, _4MB, NON_OVERLAPPING, EXPECT_SUCCESS,
> + "4MB mremap - Source PMD-aligned, Destination 1MB-aligned"),
> + MAKE_TEST(PMD, PMD, _4MB, NON_OVERLAPPING, EXPECT_SUCCESS,
> + "4MB mremap - Source PMD-aligned, Destination PMD-aligned"),
> +
> + /* Src addr PUD aligned */
> + MAKE_TEST(PUD, PTE, _2GB, NON_OVERLAPPING, EXPECT_SUCCESS,
> + "2GB mremap - Source PUD-aligned, Destination PTE-aligned"),
> + MAKE_TEST(PUD, _1MB, _2GB, NON_OVERLAPPING, EXPECT_SUCCESS,
> + "2GB mremap - Source PUD-aligned, Destination 1MB-aligned"),
> + MAKE_TEST(PUD, PMD, _2GB, NON_OVERLAPPING, EXPECT_SUCCESS,
> + "2GB mremap - Source PUD-aligned, Destination PMD-aligned"),
> + MAKE_TEST(PUD, PUD, _2GB, NON_OVERLAPPING, EXPECT_SUCCESS,
> + "2GB mremap - Source PUD-aligned, Destination PUD-aligned"),
> + };
> +
> + struct test perf_test_cases[] = {
> + /*
> + * mremap 1GB region - Page table level aligned time
> + * comparison.
> + */
> + MAKE_TEST(PTE, PTE, _1GB, NON_OVERLAPPING, EXPECT_SUCCESS,
> + "1GB mremap - Source PTE-aligned, Destination PTE-aligned"),
> + MAKE_TEST(PMD, PMD, _1GB, NON_OVERLAPPING, EXPECT_SUCCESS,
> + "1GB mremap - Source PMD-aligned, Destination PMD-aligned"),
> + MAKE_TEST(PUD, PUD, _1GB, NON_OVERLAPPING, EXPECT_SUCCESS,
> + "1GB mremap - Source PUD-aligned, Destination PUD-aligned"),
> + };
> +
> + run_perf_tests = (threshold_mb == VALIDATION_NO_THRESHOLD) ||
> + (threshold_mb * _1MB >= _1GB);
> +
> + ksft_set_plan(ARRAY_SIZE(test_cases) + (run_perf_tests ?
> + ARRAY_SIZE(perf_test_cases) : 0));
> +
> + for (i = 0; i < ARRAY_SIZE(test_cases); i++)
> + run_mremap_test_case(test_cases[i], &failures, threshold_mb,
> + pattern_seed);
> +
> + if (run_perf_tests) {
> + ksft_print_msg("\n%s\n",
> + "mremap HAVE_MOVE_PMD/PUD optimization time comparison for 1GB region:");
> + for (i = 0; i < ARRAY_SIZE(perf_test_cases); i++)
> + run_mremap_test_case(perf_test_cases[i], &failures,
> + threshold_mb, pattern_seed);
> + }
> +
> + if (failures > 0)
> + ksft_exit_fail();
> + else
> + ksft_exit_pass();
> +}
> diff --git a/tools/testing/selftests/vm/run_vmtests b/tools/testing/selftests/vm/run_vmtests
> index a3f4f30f0a2e..d578ad831813 100755
> --- a/tools/testing/selftests/vm/run_vmtests
> +++ b/tools/testing/selftests/vm/run_vmtests
> @@ -241,6 +241,17 @@ else
> echo "[PASS]"
> fi
>
> +echo "-------------------"
> +echo "running mremap_test"
> +echo "-------------------"
> +./mremap_test
> +if [ $? -ne 0 ]; then
> + echo "[FAIL]"
> + exitcode=1
> +else
> + echo "[PASS]"
> +fi
> +
> echo "-----------------"
> echo "running thuge-gen"
> echo "-----------------"
> --
> 2.28.0.1011.ga647a8990f-goog
>
