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selftests/mm: add tests for HWPOISON hugetlbfs read
authorJiaqi Yan <jiaqiyan@google.com>
Thu, 13 Jul 2023 00:18:33 +0000 (00:18 +0000)
committerAndrew Morton <akpm@linux-foundation.org>
Fri, 18 Aug 2023 17:12:27 +0000 (10:12 -0700)
Add tests for the improvement made to read operation on HWPOISON
hugetlb page with different read granularities. For each chunk size,
three read scenarios are tested:
1. Simple regression test on read without HWPOISON.
2. Sequential read page by page should succeed until encounters the 1st
   raw HWPOISON subpage.
3. After skip a raw HWPOISON subpage by lseek, read()s always succeed.

Link: https://lkml.kernel.org/r/20230713001833.3778937-5-jiaqiyan@google.com
Signed-off-by: Jiaqi Yan <jiaqiyan@google.com>
Acked-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: James Houghton <jthoughton@google.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
tools/testing/selftests/mm/.gitignore
tools/testing/selftests/mm/Makefile
tools/testing/selftests/mm/hugetlb-read-hwpoison.c [new file with mode: 0644]

index 7e2a982..cdc9ce4 100644 (file)
@@ -5,6 +5,7 @@ hugepage-mremap
 hugepage-shm
 hugepage-vmemmap
 hugetlb-madvise
+hugetlb-read-hwpoison
 khugepaged
 map_hugetlb
 map_populate
index 66d7c07..b7fce90 100644 (file)
@@ -41,6 +41,7 @@ TEST_GEN_PROGS += gup_longterm
 TEST_GEN_PROGS += gup_test
 TEST_GEN_PROGS += hmm-tests
 TEST_GEN_PROGS += hugetlb-madvise
+TEST_GEN_PROGS += hugetlb-read-hwpoison
 TEST_GEN_PROGS += hugepage-mmap
 TEST_GEN_PROGS += hugepage-mremap
 TEST_GEN_PROGS += hugepage-shm
diff --git a/tools/testing/selftests/mm/hugetlb-read-hwpoison.c b/tools/testing/selftests/mm/hugetlb-read-hwpoison.c
new file mode 100644 (file)
index 0000000..ba6cc6f
--- /dev/null
@@ -0,0 +1,322 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#define _GNU_SOURCE
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+#include <linux/magic.h>
+#include <sys/mman.h>
+#include <sys/statfs.h>
+#include <errno.h>
+#include <stdbool.h>
+
+#include "../kselftest.h"
+
+#define PREFIX " ... "
+#define ERROR_PREFIX " !!! "
+
+#define MAX_WRITE_READ_CHUNK_SIZE (getpagesize() * 16)
+#define MAX(a, b) (((a) > (b)) ? (a) : (b))
+
+enum test_status {
+       TEST_PASSED = 0,
+       TEST_FAILED = 1,
+       TEST_SKIPPED = 2,
+};
+
+static char *status_to_str(enum test_status status)
+{
+       switch (status) {
+       case TEST_PASSED:
+               return "TEST_PASSED";
+       case TEST_FAILED:
+               return "TEST_FAILED";
+       case TEST_SKIPPED:
+               return "TEST_SKIPPED";
+       default:
+               return "TEST_???";
+       }
+}
+
+static int setup_filemap(char *filemap, size_t len, size_t wr_chunk_size)
+{
+       char iter = 0;
+
+       for (size_t offset = 0; offset < len;
+            offset += wr_chunk_size) {
+               iter++;
+               memset(filemap + offset, iter, wr_chunk_size);
+       }
+
+       return 0;
+}
+
+static bool verify_chunk(char *buf, size_t len, char val)
+{
+       size_t i;
+
+       for (i = 0; i < len; ++i) {
+               if (buf[i] != val) {
+                       printf(PREFIX ERROR_PREFIX "check fail: buf[%lu] = %u != %u\n",
+                               i, buf[i], val);
+                       return false;
+               }
+       }
+
+       return true;
+}
+
+static bool seek_read_hugepage_filemap(int fd, size_t len, size_t wr_chunk_size,
+                                      off_t offset, size_t expected)
+{
+       char buf[MAX_WRITE_READ_CHUNK_SIZE];
+       ssize_t ret_count = 0;
+       ssize_t total_ret_count = 0;
+       char val = offset / wr_chunk_size + offset % wr_chunk_size;
+
+       printf(PREFIX PREFIX "init val=%u with offset=0x%lx\n", val, offset);
+       printf(PREFIX PREFIX "expect to read 0x%lx bytes of data in total\n",
+              expected);
+       if (lseek(fd, offset, SEEK_SET) < 0) {
+               perror(PREFIX ERROR_PREFIX "seek failed");
+               return false;
+       }
+
+       while (offset + total_ret_count < len) {
+               ret_count = read(fd, buf, wr_chunk_size);
+               if (ret_count == 0) {
+                       printf(PREFIX PREFIX "read reach end of the file\n");
+                       break;
+               } else if (ret_count < 0) {
+                       perror(PREFIX ERROR_PREFIX "read failed");
+                       break;
+               }
+               ++val;
+               if (!verify_chunk(buf, ret_count, val))
+                       return false;
+
+               total_ret_count += ret_count;
+       }
+       printf(PREFIX PREFIX "actually read 0x%lx bytes of data in total\n",
+              total_ret_count);
+
+       return total_ret_count == expected;
+}
+
+static bool read_hugepage_filemap(int fd, size_t len,
+                                 size_t wr_chunk_size, size_t expected)
+{
+       char buf[MAX_WRITE_READ_CHUNK_SIZE];
+       ssize_t ret_count = 0;
+       ssize_t total_ret_count = 0;
+       char val = 0;
+
+       printf(PREFIX PREFIX "expect to read 0x%lx bytes of data in total\n",
+              expected);
+       while (total_ret_count < len) {
+               ret_count = read(fd, buf, wr_chunk_size);
+               if (ret_count == 0) {
+                       printf(PREFIX PREFIX "read reach end of the file\n");
+                       break;
+               } else if (ret_count < 0) {
+                       perror(PREFIX ERROR_PREFIX "read failed");
+                       break;
+               }
+               ++val;
+               if (!verify_chunk(buf, ret_count, val))
+                       return false;
+
+               total_ret_count += ret_count;
+       }
+       printf(PREFIX PREFIX "actually read 0x%lx bytes of data in total\n",
+              total_ret_count);
+
+       return total_ret_count == expected;
+}
+
+static enum test_status
+test_hugetlb_read(int fd, size_t len, size_t wr_chunk_size)
+{
+       enum test_status status = TEST_SKIPPED;
+       char *filemap = NULL;
+
+       if (ftruncate(fd, len) < 0) {
+               perror(PREFIX ERROR_PREFIX "ftruncate failed");
+               return status;
+       }
+
+       filemap = mmap(NULL, len, PROT_READ | PROT_WRITE,
+                      MAP_SHARED | MAP_POPULATE, fd, 0);
+       if (filemap == MAP_FAILED) {
+               perror(PREFIX ERROR_PREFIX "mmap for primary mapping failed");
+               goto done;
+       }
+
+       setup_filemap(filemap, len, wr_chunk_size);
+       status = TEST_FAILED;
+
+       if (read_hugepage_filemap(fd, len, wr_chunk_size, len))
+               status = TEST_PASSED;
+
+       munmap(filemap, len);
+done:
+       if (ftruncate(fd, 0) < 0) {
+               perror(PREFIX ERROR_PREFIX "ftruncate back to 0 failed");
+               status = TEST_FAILED;
+       }
+
+       return status;
+}
+
+static enum test_status
+test_hugetlb_read_hwpoison(int fd, size_t len, size_t wr_chunk_size,
+                          bool skip_hwpoison_page)
+{
+       enum test_status status = TEST_SKIPPED;
+       char *filemap = NULL;
+       char *hwp_addr = NULL;
+       const unsigned long pagesize = getpagesize();
+
+       if (ftruncate(fd, len) < 0) {
+               perror(PREFIX ERROR_PREFIX "ftruncate failed");
+               return status;
+       }
+
+       filemap = mmap(NULL, len, PROT_READ | PROT_WRITE,
+                      MAP_SHARED | MAP_POPULATE, fd, 0);
+       if (filemap == MAP_FAILED) {
+               perror(PREFIX ERROR_PREFIX "mmap for primary mapping failed");
+               goto done;
+       }
+
+       setup_filemap(filemap, len, wr_chunk_size);
+       status = TEST_FAILED;
+
+       /*
+        * Poisoned hugetlb page layout (assume hugepagesize=2MB):
+        * |<---------------------- 1MB ---------------------->|
+        * |<---- healthy page ---->|<---- HWPOISON page ----->|
+        * |<------------------- (1MB - 8KB) ----------------->|
+        */
+       hwp_addr = filemap + len / 2 + pagesize;
+       if (madvise(hwp_addr, pagesize, MADV_HWPOISON) < 0) {
+               perror(PREFIX ERROR_PREFIX "MADV_HWPOISON failed");
+               goto unmap;
+       }
+
+       if (!skip_hwpoison_page) {
+               /*
+                * Userspace should be able to read (1MB + 1 page) from
+                * the beginning of the HWPOISONed hugepage.
+                */
+               if (read_hugepage_filemap(fd, len, wr_chunk_size,
+                                         len / 2 + pagesize))
+                       status = TEST_PASSED;
+       } else {
+               /*
+                * Userspace should be able to read (1MB - 2 pages) from
+                * HWPOISONed hugepage.
+                */
+               if (seek_read_hugepage_filemap(fd, len, wr_chunk_size,
+                                              len / 2 + MAX(2 * pagesize, wr_chunk_size),
+                                              len / 2 - MAX(2 * pagesize, wr_chunk_size)))
+                       status = TEST_PASSED;
+       }
+
+unmap:
+       munmap(filemap, len);
+done:
+       if (ftruncate(fd, 0) < 0) {
+               perror(PREFIX ERROR_PREFIX "ftruncate back to 0 failed");
+               status = TEST_FAILED;
+       }
+
+       return status;
+}
+
+static int create_hugetlbfs_file(struct statfs *file_stat)
+{
+       int fd;
+
+       fd = memfd_create("hugetlb_tmp", MFD_HUGETLB);
+       if (fd < 0) {
+               perror(PREFIX ERROR_PREFIX "could not open hugetlbfs file");
+               return -1;
+       }
+
+       memset(file_stat, 0, sizeof(*file_stat));
+       if (fstatfs(fd, file_stat)) {
+               perror(PREFIX ERROR_PREFIX "fstatfs failed");
+               goto close;
+       }
+       if (file_stat->f_type != HUGETLBFS_MAGIC) {
+               printf(PREFIX ERROR_PREFIX "not hugetlbfs file\n");
+               goto close;
+       }
+
+       return fd;
+close:
+       close(fd);
+       return -1;
+}
+
+int main(void)
+{
+       int fd;
+       struct statfs file_stat;
+       enum test_status status;
+       /* Test read() in different granularity. */
+       size_t wr_chunk_sizes[] = {
+               getpagesize() / 2, getpagesize(),
+               getpagesize() * 2, getpagesize() * 4
+       };
+       size_t i;
+
+       for (i = 0; i < ARRAY_SIZE(wr_chunk_sizes); ++i) {
+               printf("Write/read chunk size=0x%lx\n",
+                      wr_chunk_sizes[i]);
+
+               fd = create_hugetlbfs_file(&file_stat);
+               if (fd < 0)
+                       goto create_failure;
+               printf(PREFIX "HugeTLB read regression test...\n");
+               status = test_hugetlb_read(fd, file_stat.f_bsize,
+                                          wr_chunk_sizes[i]);
+               printf(PREFIX "HugeTLB read regression test...%s\n",
+                      status_to_str(status));
+               close(fd);
+               if (status == TEST_FAILED)
+                       return -1;
+
+               fd = create_hugetlbfs_file(&file_stat);
+               if (fd < 0)
+                       goto create_failure;
+               printf(PREFIX "HugeTLB read HWPOISON test...\n");
+               status = test_hugetlb_read_hwpoison(fd, file_stat.f_bsize,
+                                                   wr_chunk_sizes[i], false);
+               printf(PREFIX "HugeTLB read HWPOISON test...%s\n",
+                      status_to_str(status));
+               close(fd);
+               if (status == TEST_FAILED)
+                       return -1;
+
+               fd = create_hugetlbfs_file(&file_stat);
+               if (fd < 0)
+                       goto create_failure;
+               printf(PREFIX "HugeTLB seek then read HWPOISON test...\n");
+               status = test_hugetlb_read_hwpoison(fd, file_stat.f_bsize,
+                                                   wr_chunk_sizes[i], true);
+               printf(PREFIX "HugeTLB seek then read HWPOISON test...%s\n",
+                      status_to_str(status));
+               close(fd);
+               if (status == TEST_FAILED)
+                       return -1;
+       }
+
+       return 0;
+
+create_failure:
+       printf(ERROR_PREFIX "Abort test: failed to create hugetlbfs file\n");
+       return -1;
+}