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Subject[PATCH -next 2/2] selftests/mincore: Optimize TEST(check_file_mmap) accoring to filemap read around
Date
TEST(check_file_mmap) will fail when we set the ra_pages through
blockdev like:
/sbin/blockdev --setra 8196 /dev/sda

And, for file mmap, kernel will read 'ra_pages/2' pages of the address
on the left hand or right hand. So, add a checking of ra_pages according
to the ra_pages setting of the block dev.

I have tested it on my system like:
i=0
while [ $i -lt 9000 ]
do
/sbin/blockdev --setra $i /dev/openeuler/*
./mincore_selftest || { echo "$i test failed"; exit 1; }
let i=$i+1
done

Signed-off-by: Zhao Gongyi <zhaogongyi@huawei.com>
---
tools/testing/selftests/kselftest_harness.h | 2 +
.../selftests/mincore/mincore_selftest.c | 74 +++++++++++++++----
2 files changed, 62 insertions(+), 14 deletions(-)

diff --git a/tools/testing/selftests/kselftest_harness.h b/tools/testing/selftests/kselftest_harness.h
index 25f4d54067c0..fa40c85a1099 100644
--- a/tools/testing/selftests/kselftest_harness.h
+++ b/tools/testing/selftests/kselftest_harness.h
@@ -781,6 +781,8 @@
} \
}

+#define MIN(a, b) ((a) < (b) ? (a) : (b))
+
struct __test_results {
char reason[1024]; /* Reason for test result */
};
diff --git a/tools/testing/selftests/mincore/mincore_selftest.c b/tools/testing/selftests/mincore/mincore_selftest.c
index 287351a599a2..5eace1750fef 100644
--- a/tools/testing/selftests/mincore/mincore_selftest.c
+++ b/tools/testing/selftests/mincore/mincore_selftest.c
@@ -17,6 +17,7 @@
#include <mntent.h>
#include <sys/stat.h>
#include <linux/fs.h>
+#include <sys/ioctl.h>

#include "../kselftest.h"
#include "../kselftest_harness.h"
@@ -218,11 +219,7 @@ static struct mntent* find_mount_point(const char *name)
* Test mincore() behavior on a file-backed page.
* No pages should be loaded into memory right after the mapping. Then,
* accessing any address in the mapping range should load the page
- * containing the address and a number of subsequent pages (readahead).
- *
- * The actual readahead settings depend on the test environment, so we
- * can't make a lot of assumptions about that. This test covers the most
- * general cases.
+ * containing the address and a number of around pages (read around).
*/
TEST(check_file_mmap)
{
@@ -236,6 +233,10 @@ TEST(check_file_mmap)
int ra_pages = 0;
struct stat s;
struct mntent *mount_entry;
+ int ra_size;
+ int exp_ra_pages;
+ int odd = 0;
+ int dev_ra_pages;

mount_entry = find_mount_point(".");
ASSERT_NE(NULL, mount_entry) {
@@ -248,11 +249,29 @@ TEST(check_file_mmap)
"test is not supported");
}

+ errno = 0;
+ fd = open(mount_entry->mnt_fsname, O_RDONLY);
+ ASSERT_LT(0, fd) {
+ TH_LOG("Open %s failed: %s",
+ mount_entry->mnt_fsname, strerror(errno));
+ }
+
+ errno = 0;
+ retval = ioctl(fd, BLKRAGET, &ra_size);
+ ASSERT_EQ(0, retval) {
+ TH_LOG("Get block readahead size failed: %s", strerror(errno));
+ }
+
page_size = sysconf(_SC_PAGESIZE);
vec_size = FILE_SIZE / page_size;
if (FILE_SIZE % page_size)
vec_size++;

+ dev_ra_pages = (ra_size * 512) / page_size;
+ exp_ra_pages = MIN(vec_size / 2, dev_ra_pages / 2);
+ if (dev_ra_pages <= vec_size)
+ odd = dev_ra_pages % 2;
+
vec = calloc(vec_size, sizeof(unsigned char));
ASSERT_NE(NULL, vec) {
TH_LOG("Can't allocate array");
@@ -296,7 +315,7 @@ 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.
+ * few pages (the read around window) to be populated too.
*/
addr[FILE_SIZE / 2] = 1;
retval = mincore(addr, FILE_SIZE, vec);
@@ -310,22 +329,49 @@ TEST(check_file_mmap)
ra_pages++;
i++;
}
- EXPECT_GT(ra_pages, 0) {
- TH_LOG("No read-ahead pages found in memory");
- }

- EXPECT_LT(i, vec_size) {
- TH_LOG("Read-ahead pages reached the end of the file");
+ if (!exp_ra_pages) {
+ EXPECT_EQ(ra_pages, exp_ra_pages) {
+ TH_LOG("Check read-around pages failed");
+ }
+ } else {
+ EXPECT_EQ(ra_pages + (odd ? 0 : 1), exp_ra_pages) {
+ TH_LOG("Check read-around pages failed");
+ }
}
+
/*
- * End of the readahead window. The rest of the pages shouldn't
- * be in memory.
+ * End of the read around window. The rest of the pages shouldn't
+ * be in memory for the right hand.
*/
if (i < vec_size) {
while (i < vec_size && !vec[i])
i++;
EXPECT_EQ(vec_size, i) {
- TH_LOG("Unexpected page in memory beyond readahead window");
+ TH_LOG("Unexpected page in memory beyond read around window");
+ }
+ }
+
+ i = FILE_SIZE / 2 / page_size - 1;
+ ra_pages = 0;
+ while (i >= 0 && vec[i]) {
+ ra_pages++;
+ i--;
+ }
+
+ EXPECT_EQ(ra_pages, exp_ra_pages) {
+ TH_LOG("Check read-around pages failed");
+ }
+
+ /*
+ * End of the read around window. The rest of the pages shouldn't
+ * be in memory for the left hand.
+ */
+ if (i >= 0) {
+ while (i >= 0 && !vec[i])
+ i--;
+ EXPECT_EQ(-1, i) {
+ TH_LOG("Unexpected page in memory beyond read around window");
}
}

--
2.17.1
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