From: Zi Yan <[email protected]> It is used to test split_huge_page_to_list_to_order for pagecache THPs. Also add test cases for split_huge_page_to_list_to_order via both debugfs, truncating a file, and punching holes in a file.
Signed-off-by: Zi Yan <[email protected]> --- mm/huge_memory.c | 13 +- .../selftests/vm/split_huge_page_test.c | 192 ++++++++++++++++-- 2 files changed, 186 insertions(+), 19 deletions(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index cc70f70862d8..d6ce7be65fb2 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2999,7 +2999,7 @@ static ssize_t split_huge_pages_in_range_pid_write(struct file *file, static DEFINE_MUTEX(mutex); ssize_t ret; char input_buf[80]; /* hold pid, start_vaddr, end_vaddr */ - int pid; + int pid, to_order = 0; unsigned long vaddr_start, vaddr_end, addr; nodemask_t task_nodes; struct mm_struct *mm; @@ -3016,8 +3016,9 @@ static ssize_t split_huge_pages_in_range_pid_write(struct file *file, goto out; input_buf[79] = '\0'; - ret = sscanf(input_buf, "%d,0x%lx,0x%lx", &pid, &vaddr_start, &vaddr_end); - if (ret != 3) { + ret = sscanf(input_buf, "%d,0x%lx,0x%lx,%d", &pid, &vaddr_start, &vaddr_end, &to_order); + /* cannot split to order-1 THP, which is not possible */ + if ((ret != 3 && ret != 4) || to_order == 1) { ret = -EINVAL; goto out; } @@ -3025,8 +3026,8 @@ static ssize_t split_huge_pages_in_range_pid_write(struct file *file, vaddr_end &= PAGE_MASK; ret = strlen(input_buf); - pr_debug("split huge pages in pid: %d, vaddr: [%lx - %lx]\n", - pid, vaddr_start, vaddr_end); + pr_debug("split huge pages in pid: %d, vaddr: [%lx - %lx], to order: %d\n", + pid, vaddr_start, vaddr_end, to_order); mm = find_mm_struct(pid, &task_nodes); if (IS_ERR(mm)) { @@ -3066,7 +3067,7 @@ static ssize_t split_huge_pages_in_range_pid_write(struct file *file, if (!trylock_page(page)) continue; - if (!split_huge_page(page)) + if (!split_huge_page_to_list_to_order(page, NULL, to_order)) split++; unlock_page(page); diff --git a/tools/testing/selftests/vm/split_huge_page_test.c b/tools/testing/selftests/vm/split_huge_page_test.c index cd2ced8c1261..bfd35ae9cfd2 100644 --- a/tools/testing/selftests/vm/split_huge_page_test.c +++ b/tools/testing/selftests/vm/split_huge_page_test.c @@ -16,6 +16,7 @@ #include <sys/wait.h> #include <malloc.h> #include <stdbool.h> +#include <time.h> uint64_t pagesize; unsigned int pageshift; @@ -24,6 +25,7 @@ uint64_t pmd_pagesize; #define PMD_SIZE_PATH "/sys/kernel/mm/transparent_hugepage/hpage_pmd_size" #define SPLIT_DEBUGFS "/sys/kernel/debug/split_huge_pages_in_range_pid" #define SMAP_PATH "/proc/self/smaps" +#define THP_FS_PATH "/mnt/thp_fs" #define INPUT_MAX 80 #define PFN_MASK ((1UL<<55)-1) @@ -89,19 +91,20 @@ static int write_file(const char *path, const char *buf, size_t buflen) return (unsigned int) numwritten; } -static void write_debugfs(int pid, uint64_t vaddr_start, uint64_t vaddr_end) +static void write_debugfs(int pid, uint64_t vaddr_start, uint64_t vaddr_end, int order) { char input[INPUT_MAX]; int ret; - ret = snprintf(input, INPUT_MAX, "%d,0x%lx,0x%lx", pid, vaddr_start, - vaddr_end); + ret = snprintf(input, INPUT_MAX, "%d,0x%lx,0x%lx,%d", pid, vaddr_start, + vaddr_end, order); if (ret >= INPUT_MAX) { printf("%s: Debugfs input is too long\n", __func__); exit(EXIT_FAILURE); } - if (!write_file(SPLIT_DEBUGFS, input, ret + 1)) { + /* order == 1 is an invalid input that should be detected. */ + if (order != 1 && !write_file(SPLIT_DEBUGFS, input, ret + 1)) { perror(SPLIT_DEBUGFS); exit(EXIT_FAILURE); } @@ -118,7 +121,7 @@ static bool check_for_pattern(FILE *fp, const char *pattern, char *buf) return false; } -static uint64_t check_huge(void *addr) +static uint64_t check_huge(void *addr, const char *prefix) { uint64_t thp = 0; int ret; @@ -143,13 +146,13 @@ static uint64_t check_huge(void *addr) goto err_out; /* - * Fetch the AnonHugePages: in the same block and check the number of + * Fetch the @prefix in the same block and check the number of * hugepages. */ - if (!check_for_pattern(fp, "AnonHugePages:", buffer)) + if (!check_for_pattern(fp, prefix, buffer)) goto err_out; - if (sscanf(buffer, "AnonHugePages:%10ld kB", &thp) != 1) { + if (sscanf(&buffer[strlen(prefix)], "%10ld kB", &thp) != 1) { printf("Reading smap error\n"); exit(EXIT_FAILURE); } @@ -173,14 +176,14 @@ void split_pmd_thp(void) for (i = 0; i < len; i++) one_page[i] = (char)i; - thp_size = check_huge(one_page); + thp_size = check_huge(one_page, "AnonHugePages:"); if (!thp_size) { printf("No THP is allocatd"); exit(EXIT_FAILURE); } /* split all possible huge pages */ - write_debugfs(getpid(), (uint64_t)one_page, (uint64_t)one_page + len); + write_debugfs(getpid(), (uint64_t)one_page, (uint64_t)one_page + len, 0); for (i = 0; i < len; i++) if (one_page[i] != (char)i) { @@ -189,7 +192,7 @@ void split_pmd_thp(void) } - thp_size = check_huge(one_page); + thp_size = check_huge(one_page, "AnonHugePages:"); if (thp_size) { printf("Still %ld kB AnonHugePages not split\n", thp_size); exit(EXIT_FAILURE); @@ -237,7 +240,7 @@ void split_pte_mapped_thp(void) for (i = 0; i < len; i++) one_page[i] = (char)i; - thp_size = check_huge(one_page); + thp_size = check_huge(one_page, "AnonHugePages:"); if (!thp_size) { printf("No THP is allocatd"); exit(EXIT_FAILURE); @@ -270,7 +273,7 @@ void split_pte_mapped_thp(void) /* split all possible huge pages */ write_debugfs(getpid(), (uint64_t)pte_mapped, - (uint64_t)pte_mapped + pagesize * 4); + (uint64_t)pte_mapped + pagesize * 4, 0); /* smap does not show THPs after mremap, use kpageflags instead */ thp_size = 0; @@ -295,19 +298,182 @@ void split_pte_mapped_thp(void) close(kpageflags_fd); } +void create_pagecache_thp_and_fd(size_t fd_size, int *fd, char **addr) +{ + const char testfile[] = THP_FS_PATH "/test"; + size_t i; + int dummy; + + srand(time(NULL)); + + *fd = open(testfile, O_CREAT | O_RDWR, 0664); + if (*fd == -1) { + perror("Failed to create a file at "THP_FS_PATH); + exit(EXIT_FAILURE); + } + + for (i = 0; i < fd_size; i++) { + unsigned char byte = (unsigned char)i; + + write(*fd, &byte, sizeof(byte)); + } + close(*fd); + sync(); + *fd = open("/proc/sys/vm/drop_caches", O_WRONLY); + if (*fd == -1) { + perror("open drop_caches"); + exit(EXIT_FAILURE); + } + if (write(*fd, "3", 1) != 1) { + perror("write to drop_caches"); + exit(EXIT_FAILURE); + } + close(*fd); + + *fd = open(testfile, O_RDWR); + if (*fd == -1) { + perror("Failed to open a file at "THP_FS_PATH); + exit(EXIT_FAILURE); + } + + *addr = mmap(NULL, fd_size, PROT_READ|PROT_WRITE, MAP_SHARED, *fd, 0); + if (*addr == (char *)-1) { + perror("cannot mmap"); + exit(1); + } + madvise(*addr, fd_size, MADV_HUGEPAGE); + + for (size_t i = 0; i < fd_size; i++) + dummy += *(*addr + i); + + if (!check_huge(*addr, "FilePmdMapped:")) { + printf("No pagecache THP generated, please mount a filesystem " + "supporting pagecache THP at "THP_FS_PATH"\n"); + exit(EXIT_FAILURE); + } +} + +void split_thp_in_pagecache_to_order(size_t fd_size, int order) +{ + int fd; + char *addr; + size_t i; + + create_pagecache_thp_and_fd(fd_size, &fd, &addr); + + printf("split %ld kB pagecache page to order %d ... ", fd_size >> 10, order); + write_debugfs(getpid(), (uint64_t)addr, (uint64_t)addr + fd_size, order); + + for (i = 0; i < fd_size; i++) + if (*(addr + i) != (char)i) { + printf("%lu byte corrupted in the file\n"); + exit(EXIT_FAILURE); + } + + close(fd); + printf("done\n"); +} + +void truncate_thp_in_pagecache_to_order(size_t fd_size, int order) +{ + int fd; + char *addr; + size_t i; + + create_pagecache_thp_and_fd(fd_size, &fd, &addr); + + printf("truncate %ld kB pagecache page to size %lu kB ... ", fd_size >> 10, 4UL << order); + ftruncate(fd, pagesize << order); + + for (i = 0; i < (pagesize << order); i++) + if (*(addr + i) != (char)i) { + printf("%lu byte corrupted in the file\n"); + exit(EXIT_FAILURE); + } + + close(fd); + printf("done\n"); +} + +void punch_hole_in_pagecache_thp(size_t fd_size, off_t offset[], off_t len[], int n) +{ + int fd, j; + char *addr; + size_t i; + + create_pagecache_thp_and_fd(fd_size, &fd, &addr); + + for (j = 0; j < n; j++) { + printf("addr: %lx, punch a hole at offset %ld kB with len %ld kB ... ", + addr, offset[j] >> 10, len[j] >> 10); + fallocate(fd, FALLOC_FL_PUNCH_HOLE|FALLOC_FL_KEEP_SIZE, offset[j], len[j]); + printf("done\n"); + } + + for (i = 0; i < fd_size; i++) { + int in_hole = 0; + + for (j = 0; j < n; j++) + if (i >= offset[j] && i <= (offset[j] + len[j])) { + in_hole = 1; + break; + } + + if (in_hole) + continue; + if (*(addr + i) != (char)i) { + printf("%lu byte corrupted in the file\n", i); + exit(EXIT_FAILURE); + } + } + + close(fd); + +} + int main(int argc, char **argv) { + int i; + size_t fd_size; + off_t offset[2], len[2]; + if (geteuid() != 0) { printf("Please run the benchmark as root\n"); exit(EXIT_FAILURE); } + setbuf(stdout, NULL); + pagesize = getpagesize(); pageshift = ffs(pagesize) - 1; pmd_pagesize = read_pmd_pagesize(); + fd_size = 2 * pmd_pagesize; split_pmd_thp(); split_pte_mapped_thp(); + for (i = 8; i >= 0; i--) + split_thp_in_pagecache_to_order(fd_size, i); + + /* + * for i is 1, truncate code in the kernel should create order-0 pages + * instead of order-1 THPs, since order-1 THP is not supported. No error + * is expected. + */ + for (i = 8; i >= 0; i--) + truncate_thp_in_pagecache_to_order(fd_size, i); + + offset[0] = 123 * pagesize; + offset[1] = 4 * pagesize; + len[0] = 200 * pagesize; + len[1] = 16 * pagesize; + punch_hole_in_pagecache_thp(fd_size, offset, len, 2); + + offset[0] = 259 * pagesize; + offset[1] = 33 * pagesize; + len[0] = 129 * pagesize; + len[1] = 16 * pagesize; + punch_hole_in_pagecache_thp(fd_size, offset, len, 2); + return 0; } -- 2.28.0
