From: David Hildenbrand <david@xxxxxxxxxx> Subject: selftests/vm: add test for MADV_POPULATE_(READ|WRITE) Let's add a simple test for MADV_POPULATE_READ and MADV_POPULATE_WRITE, verifying some error handling, that population works, and that softdirty tracking works as expected. For now, limit the test to private anonymous memory. Link: https://lkml.kernel.org/r/20210419135443.12822-6-david@xxxxxxxxxx Signed-off-by: David Hildenbrand <david@xxxxxxxxxx> Cc: Arnd Bergmann <arnd@xxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxx> Cc: Oscar Salvador <osalvador@xxxxxxx> Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx> Cc: Minchan Kim <minchan@xxxxxxxxxx> Cc: Jann Horn <jannh@xxxxxxxxxx> Cc: Jason Gunthorpe <jgg@xxxxxxxx> Cc: Dave Hansen <dave.hansen@xxxxxxxxx> Cc: Hugh Dickins <hughd@xxxxxxxxxx> Cc: Rik van Riel <riel@xxxxxxxxxxx> Cc: Michael S. Tsirkin <mst@xxxxxxxxxx> Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> Cc: Vlastimil Babka <vbabka@xxxxxxx> Cc: Richard Henderson <rth@xxxxxxxxxxx> Cc: Ivan Kokshaysky <ink@xxxxxxxxxxxxxxxxxxxx> Cc: Matt Turner <mattst88@xxxxxxxxx> Cc: Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx> Cc: "James E.J. Bottomley" <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx> Cc: Helge Deller <deller@xxxxxx> Cc: Chris Zankel <chris@xxxxxxxxxx> Cc: Max Filippov <jcmvbkbc@xxxxxxxxx> Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx> Cc: Peter Xu <peterx@xxxxxxxxxx> Cc: Rolf Eike Beer <eike-kernel@xxxxxxxxx> Cc: Shuah Khan <shuah@xxxxxxxxxx> Cc: Ram Pai <linuxram@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- tools/testing/selftests/vm/.gitignore | 1 tools/testing/selftests/vm/Makefile | 1 tools/testing/selftests/vm/madv_populate.c | 342 +++++++++++++++++++ tools/testing/selftests/vm/run_vmtests.sh | 16 4 files changed, 360 insertions(+) --- a/tools/testing/selftests/vm/.gitignore~selftests-vm-add-test-for-madv_populate_readwrite +++ a/tools/testing/selftests/vm/.gitignore @@ -14,6 +14,7 @@ transhuge-stress protection_keys protection_keys_32 protection_keys_64 +madv_populate userfaultfd mlock-intersect-test mlock-random-test --- /dev/null +++ a/tools/testing/selftests/vm/madv_populate.c @@ -0,0 +1,342 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * MADV_POPULATE_READ and MADV_POPULATE_WRITE tests + * + * Copyright 2021, Red Hat, Inc. + * + * Author(s): David Hildenbrand <david@xxxxxxxxxx> + */ +#define _GNU_SOURCE +#include <stdlib.h> +#include <string.h> +#include <stdbool.h> +#include <stdint.h> +#include <unistd.h> +#include <errno.h> +#include <fcntl.h> +#include <sys/mman.h> + +#include "../kselftest.h" + +#if defined(MADV_POPULATE_READ) && defined(MADV_POPULATE_WRITE) + +/* + * For now, we're using 2 MiB of private anonymous memory for all tests. + */ +#define SIZE (2 * 1024 * 1024) + +static size_t pagesize; + +static uint64_t pagemap_get_entry(int fd, char *start) +{ + const unsigned long pfn = (unsigned long)start / pagesize; + uint64_t entry; + int ret; + + ret = pread(fd, &entry, sizeof(entry), pfn * sizeof(entry)); + if (ret != sizeof(entry)) + ksft_exit_fail_msg("reading pagemap failed\n"); + return entry; +} + +static bool pagemap_is_populated(int fd, char *start) +{ + uint64_t entry = pagemap_get_entry(fd, start); + + /* Present or swapped. */ + return entry & 0xc000000000000000ull; +} + +static bool pagemap_is_softdirty(int fd, char *start) +{ + uint64_t entry = pagemap_get_entry(fd, start); + + return entry & 0x0080000000000000ull; +} + +static void sense_support(void) +{ + char *addr; + int ret; + + addr = mmap(0, pagesize, PROT_READ | PROT_WRITE, + MAP_ANONYMOUS | MAP_PRIVATE, 0, 0); + if (!addr) + ksft_exit_fail_msg("mmap failed\n"); + + ret = madvise(addr, pagesize, MADV_POPULATE_READ); + if (ret) + ksft_exit_skip("MADV_POPULATE_READ is not available\n"); + + ret = madvise(addr, pagesize, MADV_POPULATE_WRITE); + if (ret) + ksft_exit_skip("MADV_POPULATE_WRITE is not available\n"); + + munmap(addr, pagesize); +} + +static void test_prot_read(void) +{ + char *addr; + int ret; + + ksft_print_msg("[RUN] %s\n", __func__); + + addr = mmap(0, SIZE, PROT_READ, MAP_ANONYMOUS | MAP_PRIVATE, 0, 0); + if (addr == MAP_FAILED) + ksft_exit_fail_msg("mmap failed\n"); + + ret = madvise(addr, SIZE, MADV_POPULATE_READ); + ksft_test_result(!ret, "MADV_POPULATE_READ with PROT_READ\n"); + + ret = madvise(addr, SIZE, MADV_POPULATE_WRITE); + ksft_test_result(ret == -1 && errno == EINVAL, + "MADV_POPULATE_WRITE with PROT_READ\n"); + + munmap(addr, SIZE); +} + +static void test_prot_write(void) +{ + char *addr; + int ret; + + ksft_print_msg("[RUN] %s\n", __func__); + + addr = mmap(0, SIZE, PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, 0, 0); + if (addr == MAP_FAILED) + ksft_exit_fail_msg("mmap failed\n"); + + ret = madvise(addr, SIZE, MADV_POPULATE_READ); + ksft_test_result(ret == -1 && errno == EINVAL, + "MADV_POPULATE_READ with PROT_WRITE\n"); + + ret = madvise(addr, SIZE, MADV_POPULATE_WRITE); + ksft_test_result(!ret, "MADV_POPULATE_WRITE with PROT_WRITE\n"); + + munmap(addr, SIZE); +} + +static void test_holes(void) +{ + char *addr; + int ret; + + ksft_print_msg("[RUN] %s\n", __func__); + + addr = mmap(0, SIZE, PROT_READ | PROT_WRITE, + MAP_ANONYMOUS | MAP_PRIVATE, 0, 0); + if (addr == MAP_FAILED) + ksft_exit_fail_msg("mmap failed\n"); + ret = munmap(addr + pagesize, pagesize); + if (ret) + ksft_exit_fail_msg("munmap failed\n"); + + /* Hole in the middle */ + ret = madvise(addr, SIZE, MADV_POPULATE_READ); + ksft_test_result(ret == -1 && errno == ENOMEM, + "MADV_POPULATE_READ with holes in the middle\n"); + ret = madvise(addr, SIZE, MADV_POPULATE_WRITE); + ksft_test_result(ret == -1 && errno == ENOMEM, + "MADV_POPULATE_WRITE with holes in the middle\n"); + + /* Hole at end */ + ret = madvise(addr, 2 * pagesize, MADV_POPULATE_READ); + ksft_test_result(ret == -1 && errno == ENOMEM, + "MADV_POPULATE_READ with holes at the end\n"); + ret = madvise(addr, 2 * pagesize, MADV_POPULATE_WRITE); + ksft_test_result(ret == -1 && errno == ENOMEM, + "MADV_POPULATE_WRITE with holes at the end\n"); + + /* Hole at beginning */ + ret = madvise(addr + pagesize, pagesize, MADV_POPULATE_READ); + ksft_test_result(ret == -1 && errno == ENOMEM, + "MADV_POPULATE_READ with holes at the beginning\n"); + ret = madvise(addr + pagesize, pagesize, MADV_POPULATE_WRITE); + ksft_test_result(ret == -1 && errno == ENOMEM, + "MADV_POPULATE_WRITE with holes at the beginning\n"); + + munmap(addr, SIZE); +} + +static bool range_is_populated(char *start, ssize_t size) +{ + int fd = open("/proc/self/pagemap", O_RDONLY); + bool ret = true; + + if (fd < 0) + ksft_exit_fail_msg("opening pagemap failed\n"); + for (; size > 0 && ret; size -= pagesize, start += pagesize) + if (!pagemap_is_populated(fd, start)) + ret = false; + close(fd); + return ret; +} + +static bool range_is_not_populated(char *start, ssize_t size) +{ + int fd = open("/proc/self/pagemap", O_RDONLY); + bool ret = true; + + if (fd < 0) + ksft_exit_fail_msg("opening pagemap failed\n"); + for (; size > 0 && ret; size -= pagesize, start += pagesize) + if (pagemap_is_populated(fd, start)) + ret = false; + close(fd); + return ret; +} + +static void test_populate_read(void) +{ + char *addr; + int ret; + + ksft_print_msg("[RUN] %s\n", __func__); + + addr = mmap(0, SIZE, PROT_READ | PROT_WRITE, + MAP_ANONYMOUS | MAP_PRIVATE, 0, 0); + if (addr == MAP_FAILED) + ksft_exit_fail_msg("mmap failed\n"); + ksft_test_result(range_is_not_populated(addr, SIZE), + "range initially not populated\n"); + + ret = madvise(addr, SIZE, MADV_POPULATE_READ); + ksft_test_result(!ret, "MADV_POPULATE_READ\n"); + ksft_test_result(range_is_populated(addr, SIZE), + "range is populated\n"); + + munmap(addr, SIZE); +} + +static void test_populate_write(void) +{ + char *addr; + int ret; + + ksft_print_msg("[RUN] %s\n", __func__); + + addr = mmap(0, SIZE, PROT_READ | PROT_WRITE, + MAP_ANONYMOUS | MAP_PRIVATE, 0, 0); + if (addr == MAP_FAILED) + ksft_exit_fail_msg("mmap failed\n"); + ksft_test_result(range_is_not_populated(addr, SIZE), + "range initially not populated\n"); + + ret = madvise(addr, SIZE, MADV_POPULATE_WRITE); + ksft_test_result(!ret, "MADV_POPULATE_WRITE\n"); + ksft_test_result(range_is_populated(addr, SIZE), + "range is populated\n"); + + munmap(addr, SIZE); +} + +static bool range_is_softdirty(char *start, ssize_t size) +{ + int fd = open("/proc/self/pagemap", O_RDONLY); + bool ret = true; + + if (fd < 0) + ksft_exit_fail_msg("opening pagemap failed\n"); + for (; size > 0 && ret; size -= pagesize, start += pagesize) + if (!pagemap_is_softdirty(fd, start)) + ret = false; + close(fd); + return ret; +} + +static bool range_is_not_softdirty(char *start, ssize_t size) +{ + int fd = open("/proc/self/pagemap", O_RDONLY); + bool ret = true; + + if (fd < 0) + ksft_exit_fail_msg("opening pagemap failed\n"); + for (; size > 0 && ret; size -= pagesize, start += pagesize) + if (pagemap_is_softdirty(fd, start)) + ret = false; + close(fd); + return ret; +} + +static void clear_softdirty(void) +{ + int fd = open("/proc/self/clear_refs", O_WRONLY); + const char *ctrl = "4"; + int ret; + + if (fd < 0) + ksft_exit_fail_msg("opening clear_refs failed\n"); + ret = write(fd, ctrl, strlen(ctrl)); + if (ret != strlen(ctrl)) + ksft_exit_fail_msg("writing clear_refs failed\n"); + close(fd); +} + +static void test_softdirty(void) +{ + char *addr; + int ret; + + ksft_print_msg("[RUN] %s\n", __func__); + + addr = mmap(0, SIZE, PROT_READ | PROT_WRITE, + MAP_ANONYMOUS | MAP_PRIVATE, 0, 0); + if (addr == MAP_FAILED) + ksft_exit_fail_msg("mmap failed\n"); + + /* Clear any softdirty bits. */ + clear_softdirty(); + ksft_test_result(range_is_not_softdirty(addr, SIZE), + "range is not softdirty\n"); + + /* Populating READ should set softdirty. */ + ret = madvise(addr, SIZE, MADV_POPULATE_READ); + ksft_test_result(!ret, "MADV_POPULATE_READ\n"); + ksft_test_result(range_is_not_softdirty(addr, SIZE), + "range is not softdirty\n"); + + /* Populating WRITE should set softdirty. */ + ret = madvise(addr, SIZE, MADV_POPULATE_WRITE); + ksft_test_result(!ret, "MADV_POPULATE_WRITE\n"); + ksft_test_result(range_is_softdirty(addr, SIZE), + "range is softdirty\n"); + + munmap(addr, SIZE); +} + +int main(int argc, char **argv) +{ + int err; + + pagesize = getpagesize(); + + ksft_print_header(); + ksft_set_plan(21); + + sense_support(); + test_prot_read(); + test_prot_write(); + test_holes(); + test_populate_read(); + test_populate_write(); + test_softdirty(); + + err = ksft_get_fail_cnt(); + if (err) + ksft_exit_fail_msg("%d out of %d tests failed\n", + err, ksft_test_num()); + return ksft_exit_pass(); +} + +#else /* defined(MADV_POPULATE_READ) && defined(MADV_POPULATE_WRITE) */ + +#warning "missing MADV_POPULATE_READ or MADV_POPULATE_WRITE definition" + +int main(int argc, char **argv) +{ + ksft_print_header(); + ksft_exit_skip("MADV_POPULATE_READ or MADV_POPULATE_WRITE not defined\n"); +} + +#endif /* defined(MADV_POPULATE_READ) && defined(MADV_POPULATE_WRITE) */ --- a/tools/testing/selftests/vm/Makefile~selftests-vm-add-test-for-madv_populate_readwrite +++ a/tools/testing/selftests/vm/Makefile @@ -31,6 +31,7 @@ TEST_GEN_FILES += hmm-tests TEST_GEN_FILES += hugepage-mmap TEST_GEN_FILES += hugepage-shm TEST_GEN_FILES += khugepaged +TEST_GEN_FILES += madv_populate TEST_GEN_FILES += map_fixed_noreplace TEST_GEN_FILES += map_hugetlb TEST_GEN_FILES += map_populate --- a/tools/testing/selftests/vm/run_vmtests.sh~selftests-vm-add-test-for-madv_populate_readwrite +++ a/tools/testing/selftests/vm/run_vmtests.sh @@ -346,4 +346,20 @@ else exitcode=1 fi +echo "--------------------------------------------------------" +echo "running MADV_POPULATE_READ and MADV_POPULATE_WRITE tests" +echo "--------------------------------------------------------" +./madv_populate +ret_val=$? + +if [ $ret_val -eq 0 ]; then + echo "[PASS]" +elif [ $ret_val -eq $ksft_skip ]; then + echo "[SKIP]" + exitcode=$ksft_skip +else + echo "[FAIL]" + exitcode=1 +fi + exit $exitcode _
