From 62515b5f9fdabf740efd28d5746c219f1b2e75cc Mon Sep 17 00:00:00 2001 From: Peter Xu Date: Wed, 12 Apr 2023 12:43:57 -0400 Subject: [PATCH] selftests/mm: move uffd minor test to unit test This moves the minor test to the new unit test. Rewrite the content check with char* opeartions to avoid fiddling with my_bcmp(). Drop global vars test_uffdio_minor and test_collapse, just assume test them always in common code for now. OTOH make this single test into five tests: - minor test on [shmem, hugetlb] with wp=false - minor test on [shmem, hugetlb] with wp=true - minor test + collapse on shmem only One thing to mention that we used to test COLLAPSE+WP but that doesn't sound right at all. It's possible it's silently broken but unnoticed because COLLAPSE is not part of the default test suite. Make the MADV_COLLAPSE test fail-able (by skip it when failing), because it's not guaranteed to success anyway. Drop a bunch of useless code after the move, because the unit test always use aligned num of pages and has nothing to do with n_cpus. Link: https://lkml.kernel.org/r/20230412164357.328779-1-peterx@redhat.com Signed-off-by: Peter Xu Cc: Zach O'Keefe Cc: Axel Rasmussen Cc: David Hildenbrand Cc: Dmitry Safonov <0x7f454c46@gmail.com> Cc: Mike Kravetz Cc: Mike Rapoport (IBM) Signed-off-by: Andrew Morton --- tools/testing/selftests/mm/uffd-common.c | 25 +++-- tools/testing/selftests/mm/uffd-common.h | 4 +- tools/testing/selftests/mm/uffd-stress.c | 131 +-------------------------- tools/testing/selftests/mm/uffd-unit-tests.c | 120 ++++++++++++++++++++++++ 4 files changed, 135 insertions(+), 145 deletions(-) diff --git a/tools/testing/selftests/mm/uffd-common.c b/tools/testing/selftests/mm/uffd-common.c index bc6c5c38..12ac847 100644 --- a/tools/testing/selftests/mm/uffd-common.c +++ b/tools/testing/selftests/mm/uffd-common.c @@ -13,8 +13,8 @@ volatile bool test_uffdio_copy_eexist = true; unsigned long nr_cpus, nr_pages, nr_pages_per_cpu, page_size; char *area_src, *area_src_alias, *area_dst, *area_dst_alias, *area_remap; int uffd = -1, uffd_flags, finished, *pipefd, test_type; -bool map_shared, test_collapse, test_dev_userfaultfd; -bool test_uffdio_wp = true, test_uffdio_minor = false; +bool map_shared, test_dev_userfaultfd; +bool test_uffdio_wp = true; unsigned long long *count_verify; uffd_test_ops_t *uffd_test_ops; @@ -128,15 +128,14 @@ static int shmem_allocate_area(void **alloc_area, bool is_src) char *p = NULL, *p_alias = NULL; int mem_fd = uffd_mem_fd_create(bytes * 2, false); - if (test_collapse) { - p = BASE_PMD_ADDR; - if (!is_src) - /* src map + alias + interleaved hpages */ - p += 2 * (bytes + hpage_size); - p_alias = p; - p_alias += bytes; - p_alias += hpage_size; /* Prevent src/dst VMA merge */ - } + /* TODO: clean this up. Use a static addr is ugly */ + p = BASE_PMD_ADDR; + if (!is_src) + /* src map + alias + interleaved hpages */ + p += 2 * (bytes + hpage_size); + p_alias = p; + p_alias += bytes; + p_alias += hpage_size; /* Prevent src/dst VMA merge */ *alloc_area = mmap(p, bytes, PROT_READ | PROT_WRITE, MAP_SHARED, mem_fd, offset); @@ -144,7 +143,7 @@ static int shmem_allocate_area(void **alloc_area, bool is_src) *alloc_area = NULL; return -errno; } - if (test_collapse && *alloc_area != p) + if (*alloc_area != p) err("mmap of memfd failed at %p", p); area_alias = mmap(p_alias, bytes, PROT_READ | PROT_WRITE, MAP_SHARED, @@ -154,7 +153,7 @@ static int shmem_allocate_area(void **alloc_area, bool is_src) *alloc_area = NULL; return -errno; } - if (test_collapse && area_alias != p_alias) + if (area_alias != p_alias) err("mmap of anonymous memory failed at %p", p_alias); if (is_src) diff --git a/tools/testing/selftests/mm/uffd-common.h b/tools/testing/selftests/mm/uffd-common.h index 9479a06..4bd5915 100644 --- a/tools/testing/selftests/mm/uffd-common.h +++ b/tools/testing/selftests/mm/uffd-common.h @@ -90,8 +90,8 @@ typedef struct uffd_test_ops uffd_test_ops_t; extern unsigned long nr_cpus, nr_pages, nr_pages_per_cpu, page_size; extern char *area_src, *area_src_alias, *area_dst, *area_dst_alias, *area_remap; extern int uffd, uffd_flags, finished, *pipefd, test_type; -extern bool map_shared, test_collapse, test_dev_userfaultfd; -extern bool test_uffdio_wp, test_uffdio_minor; +extern bool map_shared, test_dev_userfaultfd; +extern bool test_uffdio_wp; extern unsigned long long *count_verify; extern volatile bool test_uffdio_copy_eexist; diff --git a/tools/testing/selftests/mm/uffd-stress.c b/tools/testing/selftests/mm/uffd-stress.c index 61d025d..f9322bb 100644 --- a/tools/testing/selftests/mm/uffd-stress.c +++ b/tools/testing/selftests/mm/uffd-stress.c @@ -52,8 +52,6 @@ pthread_attr_t attr; #define swap(a, b) \ do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0) -#define factor_of_2(x) ((x) ^ ((x) & ((x) - 1))) - const char *examples = "# Run anonymous memory test on 100MiB region with 99999 bounces:\n" "./userfaultfd anon 100 99999\n\n" @@ -79,8 +77,6 @@ static void usage(void) "Supported mods:\n"); fprintf(stderr, "\tsyscall - Use userfaultfd(2) (default)\n"); fprintf(stderr, "\tdev - Use /dev/userfaultfd instead of userfaultfd(2)\n"); - fprintf(stderr, "\tcollapse - Test MADV_COLLAPSE of UFFDIO_REGISTER_MODE_MINOR\n" - "memory\n"); fprintf(stderr, "\nExample test mod usage:\n"); fprintf(stderr, "# Run anonymous memory test with /dev/userfaultfd:\n"); fprintf(stderr, "./userfaultfd anon:dev 100 99999\n\n"); @@ -584,92 +580,6 @@ static int userfaultfd_sig_test(void) return userfaults != 0; } -void check_memory_contents(char *p) -{ - unsigned long i; - uint8_t expected_byte; - void *expected_page; - - if (posix_memalign(&expected_page, page_size, page_size)) - err("out of memory"); - - for (i = 0; i < nr_pages; ++i) { - expected_byte = ~((uint8_t)(i % ((uint8_t)-1))); - memset(expected_page, expected_byte, page_size); - if (my_bcmp(expected_page, p + (i * page_size), page_size)) - err("unexpected page contents after minor fault"); - } - - free(expected_page); -} - -static int userfaultfd_minor_test(void) -{ - unsigned long p; - pthread_t uffd_mon; - char c; - struct uffd_args args = { 0 }; - - if (!test_uffdio_minor) - return 0; - - printf("testing minor faults: "); - fflush(stdout); - - uffd_test_ctx_init(uffd_minor_feature()); - - if (uffd_register(uffd, area_dst_alias, nr_pages * page_size, - false, test_uffdio_wp, true)) - err("register failure"); - - /* - * After registering with UFFD, populate the non-UFFD-registered side of - * the shared mapping. This should *not* trigger any UFFD minor faults. - */ - for (p = 0; p < nr_pages; ++p) { - memset(area_dst + (p * page_size), p % ((uint8_t)-1), - page_size); - } - - args.apply_wp = test_uffdio_wp; - if (pthread_create(&uffd_mon, &attr, uffd_poll_thread, &args)) - err("uffd_poll_thread create"); - - /* - * Read each of the pages back using the UFFD-registered mapping. We - * expect that the first time we touch a page, it will result in a minor - * fault. uffd_poll_thread will resolve the fault by bit-flipping the - * page's contents, and then issuing a CONTINUE ioctl. - */ - check_memory_contents(area_dst_alias); - - if (write(pipefd[1], &c, sizeof(c)) != sizeof(c)) - err("pipe write"); - if (pthread_join(uffd_mon, NULL)) - return 1; - - uffd_stats_report(&args, 1); - - if (test_collapse) { - printf("testing collapse of uffd memory into PMD-mapped THPs:"); - if (madvise(area_dst_alias, nr_pages * page_size, - MADV_COLLAPSE)) - err("madvise(MADV_COLLAPSE)"); - - uffd_test_ops->check_pmd_mapping(area_dst, - nr_pages * page_size / - read_pmd_pagesize()); - /* - * This won't cause uffd-fault - it purely just makes sure there - * was no corruption. - */ - check_memory_contents(area_dst_alias); - printf(" done.\n"); - } - - return args.missing_faults != 0 || args.minor_faults != nr_pages; -} - static int userfaultfd_stress(void) { void *area; @@ -782,7 +692,7 @@ static int userfaultfd_stress(void) } return userfaultfd_zeropage_test() || userfaultfd_sig_test() - || userfaultfd_events_test() || userfaultfd_minor_test(); + || userfaultfd_events_test(); } static void set_test_type(const char *type) @@ -797,13 +707,10 @@ static void set_test_type(const char *type) map_shared = true; test_type = TEST_HUGETLB; uffd_test_ops = &hugetlb_uffd_test_ops; - /* Minor faults require shared hugetlb; only enable here. */ - test_uffdio_minor = true; } else if (!strcmp(type, "shmem")) { map_shared = true; test_type = TEST_SHMEM; uffd_test_ops = &shmem_uffd_test_ops; - test_uffdio_minor = true; } } @@ -821,8 +728,6 @@ static void parse_test_type_arg(const char *raw_type) test_dev_userfaultfd = true; else if (!strcmp(token, "syscall")) test_dev_userfaultfd = false; - else if (!strcmp(token, "collapse")) - test_collapse = true; else err("unrecognized test mod '%s'", token); } @@ -830,9 +735,6 @@ static void parse_test_type_arg(const char *raw_type) if (!test_type) err("failed to parse test type argument: '%s'", raw_type); - if (test_collapse && test_type != TEST_SHMEM) - err("Unsupported test: %s", raw_type); - if (test_type == TEST_HUGETLB) page_size = default_huge_page_size(); else @@ -854,8 +756,6 @@ static void parse_test_type_arg(const char *raw_type) test_uffdio_wp = test_uffdio_wp && (features & UFFD_FEATURE_PAGEFAULT_FLAG_WP); - test_uffdio_minor = test_uffdio_minor && - (features & uffd_minor_feature()); close(uffd); uffd = -1; @@ -872,7 +772,6 @@ static void sigalrm(int sig) int main(int argc, char **argv) { size_t bytes; - size_t hpage_size = read_pmd_pagesize(); if (argc < 4) usage(); @@ -884,36 +783,8 @@ int main(int argc, char **argv) parse_test_type_arg(argv[1]); bytes = atol(argv[2]) * 1024 * 1024; - if (test_collapse && bytes & (hpage_size - 1)) - err("MiB must be multiple of %lu if :collapse mod set", - hpage_size >> 20); - nr_cpus = sysconf(_SC_NPROCESSORS_ONLN); - if (test_collapse) { - /* nr_cpus must divide (bytes / page_size), otherwise, - * area allocations of (nr_pages * paze_size) won't be a - * multiple of hpage_size, even if bytes is a multiple of - * hpage_size. - * - * This means that nr_cpus must divide (N * (2 << (H-P)) - * where: - * bytes = hpage_size * N - * hpage_size = 2 << H - * page_size = 2 << P - * - * And we want to chose nr_cpus to be the largest value - * satisfying this constraint, not larger than the number - * of online CPUs. Unfortunately, prime factorization of - * N and nr_cpus may be arbitrary, so have to search for it. - * Instead, just use the highest power of 2 dividing both - * nr_cpus and (bytes / page_size). - */ - int x = factor_of_2(nr_cpus); - int y = factor_of_2(bytes / page_size); - - nr_cpus = x < y ? x : y; - } nr_pages_per_cpu = bytes / page_size / nr_cpus; if (!nr_pages_per_cpu) { _err("invalid MiB"); diff --git a/tools/testing/selftests/mm/uffd-unit-tests.c b/tools/testing/selftests/mm/uffd-unit-tests.c index 4690c95..cba0460 100644 --- a/tools/testing/selftests/mm/uffd-unit-tests.c +++ b/tools/testing/selftests/mm/uffd-unit-tests.c @@ -329,6 +329,103 @@ static void uffd_pagemap_test(void) uffd_test_pass(); } +static void check_memory_contents(char *p) +{ + unsigned long i, j; + uint8_t expected_byte; + + for (i = 0; i < nr_pages; ++i) { + expected_byte = ~((uint8_t)(i % ((uint8_t)-1))); + for (j = 0; j < page_size; j++) { + uint8_t v = *(uint8_t *)(p + (i * page_size) + j); + if (v != expected_byte) + err("unexpected page contents"); + } + } +} + +static void uffd_minor_test_common(bool test_collapse, bool test_wp) +{ + unsigned long p; + pthread_t uffd_mon; + char c; + struct uffd_args args = { 0 }; + + /* + * NOTE: MADV_COLLAPSE is not yet compatible with WP, so testing + * both do not make much sense. + */ + assert(!(test_collapse && test_wp)); + + if (uffd_register(uffd, area_dst_alias, nr_pages * page_size, + /* NOTE! MADV_COLLAPSE may not work with uffd-wp */ + false, test_wp, true)) + err("register failure"); + + /* + * After registering with UFFD, populate the non-UFFD-registered side of + * the shared mapping. This should *not* trigger any UFFD minor faults. + */ + for (p = 0; p < nr_pages; ++p) + memset(area_dst + (p * page_size), p % ((uint8_t)-1), + page_size); + + args.apply_wp = test_wp; + if (pthread_create(&uffd_mon, NULL, uffd_poll_thread, &args)) + err("uffd_poll_thread create"); + + /* + * Read each of the pages back using the UFFD-registered mapping. We + * expect that the first time we touch a page, it will result in a minor + * fault. uffd_poll_thread will resolve the fault by bit-flipping the + * page's contents, and then issuing a CONTINUE ioctl. + */ + check_memory_contents(area_dst_alias); + + if (write(pipefd[1], &c, sizeof(c)) != sizeof(c)) + err("pipe write"); + if (pthread_join(uffd_mon, NULL)) + err("join() failed"); + + if (test_collapse) { + if (madvise(area_dst_alias, nr_pages * page_size, + MADV_COLLAPSE)) { + /* It's fine to fail for this one... */ + uffd_test_skip("MADV_COLLAPSE failed"); + return; + } + + uffd_test_ops->check_pmd_mapping(area_dst, + nr_pages * page_size / + read_pmd_pagesize()); + /* + * This won't cause uffd-fault - it purely just makes sure there + * was no corruption. + */ + check_memory_contents(area_dst_alias); + } + + if (args.missing_faults != 0 || args.minor_faults != nr_pages) + uffd_test_fail("stats check error"); + else + uffd_test_pass(); +} + +void uffd_minor_test(void) +{ + uffd_minor_test_common(false, false); +} + +void uffd_minor_wp_test(void) +{ + uffd_minor_test_common(false, true); +} + +void uffd_minor_collapse_test(void) +{ + uffd_minor_test_common(true, false); +} + uffd_test_case_t uffd_tests[] = { { .name = "pagemap", @@ -343,6 +440,29 @@ uffd_test_case_t uffd_tests[] = { .uffd_feature_required = UFFD_FEATURE_PAGEFAULT_FLAG_WP | UFFD_FEATURE_WP_UNPOPULATED, }, + { + .name = "minor", + .uffd_fn = uffd_minor_test, + .mem_targets = MEM_SHMEM | MEM_HUGETLB, + .uffd_feature_required = + UFFD_FEATURE_MINOR_HUGETLBFS | UFFD_FEATURE_MINOR_SHMEM, + }, + { + .name = "minor-wp", + .uffd_fn = uffd_minor_wp_test, + .mem_targets = MEM_SHMEM | MEM_HUGETLB, + .uffd_feature_required = + UFFD_FEATURE_MINOR_HUGETLBFS | UFFD_FEATURE_MINOR_SHMEM | + UFFD_FEATURE_PAGEFAULT_FLAG_WP, + }, + { + .name = "minor-collapse", + .uffd_fn = uffd_minor_collapse_test, + /* MADV_COLLAPSE only works with shmem */ + .mem_targets = MEM_SHMEM, + /* We can't test MADV_COLLAPSE, so try our luck */ + .uffd_feature_required = UFFD_FEATURE_MINOR_SHMEM, + }, }; int main(int argc, char *argv[]) -- 2.7.4