diff --git a/tools/mm/Makefile b/tools/mm/Makefile index 7bb03606b9ea..15791c1c5b28 100644 --- a/tools/mm/Makefile +++ b/tools/mm/Makefile @@ -3,7 +3,7 @@ # include ../scripts/Makefile.include -BUILD_TARGETS=page-types slabinfo page_owner_sort +BUILD_TARGETS=page-types slabinfo page_owner_sort thp_swap_allocator_test INSTALL_TARGETS = $(BUILD_TARGETS) thpmaps LIB_DIR = ../lib/api diff --git a/tools/mm/thp_swap_allocator_test.c b/tools/mm/thp_swap_allocator_test.c new file mode 100644 index 000000000000..83afc52275a5 --- /dev/null +++ b/tools/mm/thp_swap_allocator_test.c @@ -0,0 +1,234 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * thp_swap_allocator_test + * + * The purpose of this test program is helping check if THP swpout + * can correctly get swap slots to swap out as a whole instead of + * being split. It randomly releases swap entries through madvise + * DONTNEED and swapin/out on two memory areas: a memory area for + * 64KB THP and the other area for small folios. The second memory + * can be enabled by "-s". + * Before running the program, we need to setup a zRAM or similar + * swap device by: + * echo lzo > /sys/block/zram0/comp_algorithm + * echo 64M > /sys/block/zram0/disksize + * echo never > /sys/kernel/mm/transparent_hugepage/hugepages-2048kB/enabled + * echo always > /sys/kernel/mm/transparent_hugepage/hugepages-64kB/enabled + * mkswap /dev/zram0 + * swapon /dev/zram0 + * The expected result should be 0% anon swpout fallback ratio w/ or + * w/o "-s". + * + * Author(s): Barry Song + */ + +#define _GNU_SOURCE +#include +#include +#include +#include +#include +#include +#include +#include + +#define MEMSIZE_MTHP (60 * 1024 * 1024) +#define MEMSIZE_SMALLFOLIO (4 * 1024 * 1024) +#define ALIGNMENT_MTHP (64 * 1024) +#define ALIGNMENT_SMALLFOLIO (4 * 1024) +#define TOTAL_DONTNEED_MTHP (16 * 1024 * 1024) +#define TOTAL_DONTNEED_SMALLFOLIO (1 * 1024 * 1024) +#define MTHP_FOLIO_SIZE (64 * 1024) + +#define SWPOUT_PATH \ + "/sys/kernel/mm/transparent_hugepage/hugepages-64kB/stats/swpout" +#define SWPOUT_FALLBACK_PATH \ + "/sys/kernel/mm/transparent_hugepage/hugepages-64kB/stats/swpout_fallback" + +static void *aligned_alloc_mem(size_t size, size_t alignment) +{ + void *mem = NULL; + + if (posix_memalign(&mem, alignment, size) != 0) { + perror("posix_memalign"); + return NULL; + } + return mem; +} + +/* + * This emulates the behavior of native libc and Java heap, + * as well as process exit and munmap. It helps generate mTHP + * and ensures that iterations can proceed with mTHP, as we + * currently don't support large folios swap-in. + */ +static void random_madvise_dontneed(void *mem, size_t mem_size, + size_t align_size, size_t total_dontneed_size) +{ + size_t num_pages = total_dontneed_size / align_size; + size_t i; + size_t offset; + void *addr; + + for (i = 0; i < num_pages; ++i) { + offset = (rand() % (mem_size / align_size)) * align_size; + addr = (char *)mem + offset; + if (madvise(addr, align_size, MADV_DONTNEED) != 0) + perror("madvise dontneed"); + + memset(addr, 0x11, align_size); + } +} + +static void random_swapin(void *mem, size_t mem_size, + size_t align_size, size_t total_swapin_size) +{ + size_t num_pages = total_swapin_size / align_size; + size_t i; + size_t offset; + void *addr; + + for (i = 0; i < num_pages; ++i) { + offset = (rand() % (mem_size / align_size)) * align_size; + addr = (char *)mem + offset; + memset(addr, 0x11, align_size); + } +} + +static unsigned long read_stat(const char *path) +{ + FILE *file; + unsigned long value; + + file = fopen(path, "r"); + if (!file) { + perror("fopen"); + return 0; + } + + if (fscanf(file, "%lu", &value) != 1) { + perror("fscanf"); + fclose(file); + return 0; + } + + fclose(file); + return value; +} + +int main(int argc, char *argv[]) +{ + int use_small_folio = 0, aligned_swapin = 0; + void *mem1 = NULL, *mem2 = NULL; + int i; + + for (i = 1; i < argc; ++i) { + if (strcmp(argv[i], "-s") == 0) + use_small_folio = 1; + else if (strcmp(argv[i], "-a") == 0) + aligned_swapin = 1; + } + + mem1 = aligned_alloc_mem(MEMSIZE_MTHP, ALIGNMENT_MTHP); + if (mem1 == NULL) { + fprintf(stderr, "Failed to allocate large folios memory\n"); + return EXIT_FAILURE; + } + + if (madvise(mem1, MEMSIZE_MTHP, MADV_HUGEPAGE) != 0) { + perror("madvise hugepage for mem1"); + free(mem1); + return EXIT_FAILURE; + } + + if (use_small_folio) { + mem2 = aligned_alloc_mem(MEMSIZE_SMALLFOLIO, ALIGNMENT_MTHP); + if (mem2 == NULL) { + fprintf(stderr, "Failed to allocate small folios memory\n"); + free(mem1); + return EXIT_FAILURE; + } + + if (madvise(mem2, MEMSIZE_SMALLFOLIO, MADV_NOHUGEPAGE) != 0) { + perror("madvise nohugepage for mem2"); + free(mem1); + free(mem2); + return EXIT_FAILURE; + } + } + + /* warm-up phase to occupy the swapfile */ + memset(mem1, 0x11, MEMSIZE_MTHP); + madvise(mem1, MEMSIZE_MTHP, MADV_PAGEOUT); + if (use_small_folio) { + memset(mem2, 0x11, MEMSIZE_SMALLFOLIO); + madvise(mem2, MEMSIZE_SMALLFOLIO, MADV_PAGEOUT); + } + + /* iterations with newly created mTHP, swap-in, and swap-out */ + for (i = 0; i < 100; ++i) { + unsigned long initial_swpout; + unsigned long initial_swpout_fallback; + unsigned long final_swpout; + unsigned long final_swpout_fallback; + unsigned long swpout_inc; + unsigned long swpout_fallback_inc; + double fallback_percentage; + + initial_swpout = read_stat(SWPOUT_PATH); + initial_swpout_fallback = read_stat(SWPOUT_FALLBACK_PATH); + + /* + * The following setup creates a 1:1 ratio of mTHP to small folios + * since large folio swap-in isn't supported yet. Once we support + * mTHP swap-in, we'll likely need to reduce MEMSIZE_MTHP and + * increase MEMSIZE_SMALLFOLIO to maintain the ratio. + */ + random_swapin(mem1, MEMSIZE_MTHP, + aligned_swapin ? ALIGNMENT_MTHP : ALIGNMENT_SMALLFOLIO, + TOTAL_DONTNEED_MTHP); + random_madvise_dontneed(mem1, MEMSIZE_MTHP, ALIGNMENT_MTHP, + TOTAL_DONTNEED_MTHP); + + if (use_small_folio) { + random_swapin(mem2, MEMSIZE_SMALLFOLIO, + ALIGNMENT_SMALLFOLIO, + TOTAL_DONTNEED_SMALLFOLIO); + } + + if (madvise(mem1, MEMSIZE_MTHP, MADV_PAGEOUT) != 0) { + perror("madvise pageout for mem1"); + free(mem1); + if (mem2 != NULL) + free(mem2); + return EXIT_FAILURE; + } + + if (use_small_folio) { + if (madvise(mem2, MEMSIZE_SMALLFOLIO, MADV_PAGEOUT) != 0) { + perror("madvise pageout for mem2"); + free(mem1); + free(mem2); + return EXIT_FAILURE; + } + } + + final_swpout = read_stat(SWPOUT_PATH); + final_swpout_fallback = read_stat(SWPOUT_FALLBACK_PATH); + + swpout_inc = final_swpout - initial_swpout; + swpout_fallback_inc = final_swpout_fallback - initial_swpout_fallback; + + fallback_percentage = (double)swpout_fallback_inc / + (swpout_fallback_inc + swpout_inc) * 100; + + printf("Iteration %d: swpout inc: %lu, swpout fallback inc: %lu, Fallback percentage: %.2f%%\n", + i + 1, swpout_inc, swpout_fallback_inc, fallback_percentage); + } + + free(mem1); + if (mem2 != NULL) + free(mem2); + + return EXIT_SUCCESS; +}