The readahead size used to be 2MB, thus it's reasonable to set the file
size as 4MB when checking check_file_mmap().
However since commit c2e4cd57cfa1 ("block: lift setting the readahead
size into the block layer"), readahead size could be as large as twice
the io_opt, and thus the hardcoded file size no longer works.
check_file_mmap() may report "Read-ahead pages reached the end of the
file" when the readahead size actually exceeds the file size in this
case.
Reported-by: James Wang <jnwang@xxxxxxxxxxxxxxxxx>
Signed-off-by: Jeffle Xu <jefflexu@xxxxxxxxxxxxxxxxx>
---
chnages since v2:
- add 'Reported-by'
chnages since v1:
- add the test name "mincore" in the subject line
- add the error message in commit message
- rename @filesize to @file_size to keep a more consistent naming
convention
---
.../selftests/mincore/mincore_selftest.c | 57 +++++++++++++++----
1 file changed, 47 insertions(+), 10 deletions(-)
diff --git a/tools/testing/selftests/mincore/mincore_selftest.c b/tools/testing/selftests/mincore/mincore_selftest.c
index 5a1e85ff5d32..3ca542934080 100644
--- a/tools/testing/selftests/mincore/mincore_selftest.c
+++ b/tools/testing/selftests/mincore/mincore_selftest.c
@@ -15,6 +15,11 @@
#include <string.h>
#include <fcntl.h>
#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/ioctl.h>
+#include <sys/sysmacros.h>
+#include <sys/mount.h>
#include "../kselftest.h"
#include "../kselftest_harness.h"
@@ -195,10 +200,42 @@ TEST(check_file_mmap)
int fd;
int i;
int ra_pages = 0;
+ long ra_size, file_size;
+ struct stat stats;
+ dev_t devt;
+ unsigned int major, minor;
+ char devpath[32];
+
+ retval = stat(".", &stats);
+ ASSERT_EQ(0, retval) {
+ TH_LOG("Can't stat pwd: %s", strerror(errno));
+ }
+
+ devt = stats.st_dev;
+ major = major(devt);
+ minor = minor(devt);
+ snprintf(devpath, sizeof(devpath), "/dev/block/%u:%u", major, minor);
+
+ fd = open(devpath, O_RDONLY);
+ ASSERT_NE(-1, fd) {
+ TH_LOG("Can't open underlying disk %s", strerror(errno));
+ }
+
+ retval = ioctl(fd, BLKRAGET, &ra_size);
+ ASSERT_EQ(0, retval) {
+ TH_LOG("Error ioctl with the underlying disk: %s", strerror(errno));
+ }
+
+ /*
+ * BLKRAGET ioctl returns the readahead size in sectors (512 bytes).
+ * Make file_size large enough to contain the readahead window.
+ */
+ ra_size *= 512;
+ file_size = ra_size * 2;
page_size = sysconf(_SC_PAGESIZE);
- vec_size = FILE_SIZE / page_size;
- if (FILE_SIZE % page_size)
+ vec_size = file_size / page_size;
+ if (file_size % page_size)
vec_size++;
vec = calloc(vec_size, sizeof(unsigned char));
@@ -213,7 +250,7 @@ TEST(check_file_mmap)
strerror(errno));
}
errno = 0;
- retval = fallocate(fd, 0, 0, FILE_SIZE);
+ retval = fallocate(fd, 0, 0, file_size);
ASSERT_EQ(0, retval) {
TH_LOG("Error allocating space for the temporary file: %s",
strerror(errno));
@@ -223,12 +260,12 @@ TEST(check_file_mmap)
* Map the whole file, the pages shouldn't be fetched yet.
*/
errno = 0;
- addr = mmap(NULL, FILE_SIZE, PROT_READ | PROT_WRITE,
+ addr = mmap(NULL, file_size, PROT_READ | PROT_WRITE,
MAP_SHARED, fd, 0);
ASSERT_NE(MAP_FAILED, addr) {
TH_LOG("mmap error: %s", strerror(errno));
}
- retval = mincore(addr, FILE_SIZE, vec);
+ retval = mincore(addr, file_size, vec);
ASSERT_EQ(0, retval);
for (i = 0; i < vec_size; i++) {
ASSERT_EQ(0, vec[i]) {
@@ -240,14 +277,14 @@ TEST(check_file_mmap)
* Touch a page in the middle of the mapping. We expect the next
* few pages (the readahead window) to be populated too.
*/
- addr[FILE_SIZE / 2] = 1;
- retval = mincore(addr, FILE_SIZE, vec);
+ addr[file_size / 2] = 1;
+ retval = mincore(addr, file_size, vec);
ASSERT_EQ(0, retval);
- ASSERT_EQ(1, vec[FILE_SIZE / 2 / page_size]) {
+ ASSERT_EQ(1, vec[file_size / 2 / page_size]) {
TH_LOG("Page not found in memory after use");
}
- i = FILE_SIZE / 2 / page_size + 1;
+ i = file_size / 2 / page_size + 1;
while (i < vec_size && vec[i]) {
ra_pages++;
i++;
@@ -271,7 +308,7 @@ TEST(check_file_mmap)
}
}
- munmap(addr, FILE_SIZE);
+ munmap(addr, file_size);
close(fd);
free(vec);
}
--
2.27.0
