From: Alexander Zhu <alexlzhu@xxxxxx>
Self tests to verify the RssAnon value to make sure zero
pages are not remapped except in the case of userfaultfd.
Also includes a self test for the userfaultfd use case.
Signed-off-by: Alexander Zhu <alexlzhu@xxxxxx>
---
v1 to v2
-Modified split_huge_page self test based off more recent changes.
RFC to v1
Also added a self test to verify that userfaultfd change is working.
.../selftests/vm/split_huge_page_test.c | 115 +++++++++++++++++-
tools/testing/selftests/vm/vm_util.c | 23 ++++
tools/testing/selftests/vm/vm_util.h | 3 +
3 files changed, 140 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/vm/split_huge_page_test.c b/tools/testing/selftests/vm/split_huge_page_test.c
index 76e1c36dd9e5..42f0e79a4508 100644
--- a/tools/testing/selftests/vm/split_huge_page_test.c
+++ b/tools/testing/selftests/vm/split_huge_page_test.c
@@ -16,6 +16,9 @@
#include <sys/mount.h>
#include <malloc.h>
#include <stdbool.h>
+#include <sys/syscall.h> /* Definition of SYS_* constants */
+#include <linux/userfaultfd.h>
+#include <sys/ioctl.h>
#include "vm_util.h"
uint64_t pagesize;
@@ -88,6 +91,115 @@ static void write_debugfs(const char *fmt, ...)
}
}
+static char *allocate_zero_filled_hugepage(size_t len)
+{
+ char *result;
+ size_t i;
+
+ result = memalign(pmd_pagesize, len);
+ if (!result) {
+ printf("Fail to allocate memory\n");
+ exit(EXIT_FAILURE);
+ }
+
+ madvise(result, len, MADV_HUGEPAGE);
+
+ for (i = 0; i < len; i++)
+ result[i] = (char)0;
+
+ return result;
+}
+
+static void verify_rss_anon_split_huge_page_all_zeroes(char *one_page, int nr_hpages, size_t len)
+{
+ uint64_t rss_anon_before, rss_anon_after;
+ size_t i;
+
+ if (!check_huge_anon(one_page, 4, pmd_pagesize)) {
+ printf("No THP is allocated\n");
+ exit(EXIT_FAILURE);
+ }
+
+ rss_anon_before = rss_anon();
+ if (!rss_anon_before) {
+ printf("No RssAnon is allocated before split\n");
+ exit(EXIT_FAILURE);
+ }
+
+ /* split all THPs */
+ write_debugfs(PID_FMT, getpid(), (uint64_t)one_page,
+ (uint64_t)one_page + len);
+
+ for (i = 0; i < len; i++)
+ if (one_page[i] != (char)0) {
+ printf("%ld byte corrupted\n", i);
+ exit(EXIT_FAILURE);
+ }
+
+ if (!check_huge_anon(one_page, 0, pmd_pagesize)) {
+ printf("Still AnonHugePages not split\n");
+ exit(EXIT_FAILURE);
+ }
+
+ rss_anon_after = rss_anon();
+ if (rss_anon_after >= rss_anon_before) {
+ printf("Incorrect RssAnon value. Before: %ld After: %ld\n",
+ rss_anon_before, rss_anon_after);
+ exit(EXIT_FAILURE);
+ }
+}
+
+void split_pmd_zero_pages(void)
+{
+ char *one_page;
+ int nr_hpages = 4;
+ size_t len = nr_hpages * pmd_pagesize;
+
+ one_page = allocate_zero_filled_hugepage(len);
+ verify_rss_anon_split_huge_page_all_zeroes(one_page, nr_hpages, len);
+ printf("Split zero filled huge pages successful\n");
+ free(one_page);
+}
+
+void split_pmd_zero_pages_uffd(void)
+{
+ char *one_page;
+ int nr_hpages = 4;
+ size_t len = nr_hpages * pmd_pagesize;
+ long uffd; /* userfaultfd file descriptor */
+ struct uffdio_api uffdio_api;
+ struct uffdio_register uffdio_register;
+
+ /* Create and enable userfaultfd object. */
+
+ uffd = syscall(__NR_userfaultfd, O_CLOEXEC | O_NONBLOCK);
+ if (uffd == -1) {
+ perror("userfaultfd");
+ exit(1);
+ }
+
+ uffdio_api.api = UFFD_API;
+ uffdio_api.features = 0;
+ if (ioctl(uffd, UFFDIO_API, &uffdio_api) == -1) {
+ perror("ioctl-UFFDIO_API");
+ exit(1);
+ }
+
+ one_page = allocate_zero_filled_hugepage(len);
+
+ uffdio_register.range.start = (unsigned long)one_page;
+ uffdio_register.range.len = len;
+ uffdio_register.mode = UFFDIO_REGISTER_MODE_WP;
+ if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register) == -1) {
+ perror("ioctl-UFFDIO_REGISTER");
+ exit(1);
+ }
+
+ verify_rss_anon_split_huge_page_all_zeroes(one_page, nr_hpages, len);
+ printf("Split zero filled huge pages with uffd successful\n");
+ free(one_page);
+}
+
void split_pmd_thp(void)
{
char *one_page;
@@ -121,7 +233,6 @@ void split_pmd_thp(void)
exit(EXIT_FAILURE);
}
-
if (check_huge_anon(one_page, 0, pmd_pagesize)) {
printf("Still AnonHugePages not split\n");
exit(EXIT_FAILURE);
@@ -301,6 +412,8 @@ int main(int argc, char **argv)
pageshift = ffs(pagesize) - 1;
pmd_pagesize = read_pmd_pagesize();
+ split_pmd_zero_pages();
+ split_pmd_zero_pages_uffd();
split_pmd_thp();
split_pte_mapped_thp();
split_file_backed_thp();
diff --git a/tools/testing/selftests/vm/vm_util.c b/tools/testing/selftests/vm/vm_util.c
index f11f8adda521..72f3edc64aaf 100644
--- a/tools/testing/selftests/vm/vm_util.c
+++ b/tools/testing/selftests/vm/vm_util.c
@@ -6,6 +6,7 @@
#define PMD_SIZE_FILE_PATH "/sys/kernel/mm/transparent_hugepage/hpage_pmd_size"
#define SMAP_FILE_PATH "/proc/self/smaps"
+#define STATUS_FILE_PATH "/proc/self/status"
#define MAX_LINE_LENGTH 500
uint64_t pagemap_get_entry(int fd, char *start)
@@ -72,6 +73,28 @@ uint64_t read_pmd_pagesize(void)
return strtoul(buf, NULL, 10);
}
+uint64_t rss_anon(void)
+{
+ uint64_t rss_anon = 0;
+ int ret;
+ FILE *fp;
+ char buffer[MAX_LINE_LENGTH];
+
+ fp = fopen(STATUS_FILE_PATH, "r");
+ if (!fp)
+ ksft_exit_fail_msg("%s: Failed to open file %s\n", __func__, STATUS_FILE_PATH);
+
+ if (!check_for_pattern(fp, "RssAnon:", buffer, sizeof(buffer)))
+ goto err_out;
+
+ if (sscanf(buffer, "RssAnon:%10ld kB", &rss_anon) != 1)
+ ksft_exit_fail_msg("Reading status error\n");
+
+err_out:
+ fclose(fp);
+ return rss_anon;
+}
+
bool __check_huge(void *addr, char *pattern, int nr_hpages,
uint64_t hpage_size)
{
diff --git a/tools/testing/selftests/vm/vm_util.h b/tools/testing/selftests/vm/vm_util.h
index 5c35de454e08..dd1885f66097 100644
--- a/tools/testing/selftests/vm/vm_util.h
+++ b/tools/testing/selftests/vm/vm_util.h
@@ -1,12 +1,15 @@
/* SPDX-License-Identifier: GPL-2.0 */
#include <stdint.h>
#include <stdbool.h>
+#include <stddef.h>
+#include <stdio.h>
uint64_t pagemap_get_entry(int fd, char *start);
bool pagemap_is_softdirty(int fd, char *start);
void clear_softdirty(void);
bool check_for_pattern(FILE *fp, const char *pattern, char *buf, size_t len);
uint64_t read_pmd_pagesize(void);
+uint64_t rss_anon(void);
bool check_huge_anon(void *addr, int nr_hpages, uint64_t hpage_size);
bool check_huge_file(void *addr, int nr_hpages, uint64_t hpage_size);
bool check_huge_shmem(void *addr, int nr_hpages, uint64_t hpage_size);
--
2.30.2
