From: Zi Yan <z...@nvidia.com>
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 and truncating a file.
Signed-off-by: Zi Yan <z...@nvidia.com>
---
mm/huge_memory.c | 13 +--
.../selftests/vm/split_huge_page_test.c | 102 +++++++++++++++++-
2 files changed, 105 insertions(+), 10 deletions(-)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 88f50da40c9b..b7470607a08b 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2974,7 +2974,7 @@ 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;
@@ -2990,8 +2990,9 @@ static ssize_t split_huge_pages_in_range_pid_write(struct
file *file,
goto out;
input_buf[80] = '\0';
- ret = sscanf(input_buf, "%d,%lx,%lx", &pid, &vaddr_start, &vaddr_end);
- if (ret != 3) {
+ ret = sscanf(input_buf, "%d,%lx,%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;
}
@@ -2999,8 +3000,8 @@ 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)) {
@@ -3038,7 +3039,7 @@ static ssize_t split_huge_pages_in_range_pid_write(struct
file *file,
addr += page_size(page) - PAGE_SIZE;
/* reset addr if split fails */
- if (split_huge_page(page))
+ if (split_huge_page_to_list_to_order(page, NULL, to_order))
addr -= (page_size(page) - PAGE_SIZE);
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 c8a32ae9e13a..bcbc5a9d327c 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>
#define PAGE_4KB (4096UL)
#define PAGE_2MB (512UL*PAGE_4KB)
@@ -31,6 +32,7 @@
#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
static int write_file(const char *path, const char *buf, size_t buflen)
@@ -50,13 +52,13 @@ 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,%lx,%lx", pid, vaddr_start,
- vaddr_end);
+ ret = snprintf(input, INPUT_MAX, "%d,%lx,%lx,%d", pid, vaddr_start,
+ vaddr_end, order);
if (ret >= INPUT_MAX) {
printf("%s: Debugfs input is too long\n", __func__);
exit(EXIT_FAILURE);
@@ -139,7 +141,7 @@ void split_pmd_thp(void)
}
/* 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);
*one_page = 0;
@@ -153,9 +155,101 @@ void split_pmd_thp(void)
free(one_page);
}
+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);
+
+ for (i = 0; i < fd_size; i++) {
+ unsigned char byte = rand();
+
+ 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);
+
+ *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);
+}
+
+void split_thp_in_pagecache_to_order(int order)
+{
+ int fd;
+ char *addr;
+ size_t fd_size = 2 * PAGE_2MB, 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++)
+ *(addr + i) = (char)i;
+
+ close(fd);
+ printf("done\n");
+}
+
+void truncate_thp_in_pagecache_to_order(int order)
+{
+ int fd;
+ char *addr;
+ size_t fd_size = 2 * PAGE_2MB, 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, PAGE_4KB << order);
+
+ for (i = 0; i < (PAGE_4KB << order); i++)
+ *(addr + i) = (char)i;
+
+ close(fd);
+ printf("done\n");
+}
+
int main(int argc, char **argv)
{
+ int i;
+
+ if (geteuid() != 0) {
+ printf("Please run the benchmark as root\n");
+ exit(EXIT_FAILURE);
+ }
+
split_pmd_thp();
+ for (i = 8; i >= 0; i--)
+ if (i != 1)
+ split_thp_in_pagecache_to_order(i);
+
+ for (i = 8; i >= 0; i--)
+ if (i != 1)
+ truncate_thp_in_pagecache_to_order(i);
+
return 0;
}
--
2.28.0
