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selftests: update ksm inheritance tests for prctl fork/exec 

To reproduce the issue mentioned by [1], this add a setting of
pages_to_scan and sleep_millisecs at the start of test_prctl_fork_exec(). 
The main change is just raise the scanning frequency of ksmd.

[1] https://lore.kernel.org/all/202510012256278259zrhgATlLA2C510DMD3qI@zte.com.cn/

Link: https://lkml.kernel.org/r/20251007182935207jm31wCIgLpZg5XbXQY64S@zte.com.cn
Signed-off-by: xu xin <xu.xin16@zte.com.cn>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jinjiang Tu <tujinjiang@huawei.com>
Cc: Stefan Roesch <shr@devkernel.io>
Cc: Wang Yaxin <wang.yaxin@zte.com.cn>
Cc: Yang Yang <yang.yang29@zte.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
pull/1354/merge
xu xin 2025-10-07 18:29:35 +08:00 committed by Andrew Morton
parent 590c03ca6a
commit bda7bf0684
1 changed files with 57 additions and 0 deletions
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57
tools/testing/selftests/mm/ksm_functional_tests.c
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@ -38,6 +38,8 @@ enum ksm_merge_mode {
};
static int mem_fd;
static int pages_to_scan_fd;
static int sleep_millisecs_fd;
static int pagemap_fd;
static size_t pagesize;
@ -493,6 +495,46 @@ static void test_prctl_fork(void)
ksft_test_result_pass("PR_SET_MEMORY_MERGE value is inherited\n");
}
static int start_ksmd_and_set_frequency(char *pages_to_scan, char *sleep_ms)
{
int ksm_fd;
ksm_fd = open("/sys/kernel/mm/ksm/run", O_RDWR);
if (ksm_fd < 0)
return -errno;
if (write(ksm_fd, "1", 1) != 1)
return -errno;
if (write(pages_to_scan_fd, pages_to_scan, strlen(pages_to_scan)) <= 0)
return -errno;
if (write(sleep_millisecs_fd, sleep_ms, strlen(sleep_ms)) <= 0)
return -errno;
return 0;
}
static int stop_ksmd_and_restore_frequency(void)
{
int ksm_fd;
ksm_fd = open("/sys/kernel/mm/ksm/run", O_RDWR);
if (ksm_fd < 0)
return -errno;
if (write(ksm_fd, "2", 1) != 1)
return -errno;
if (write(pages_to_scan_fd, "100", 3) <= 0)
return -errno;
if (write(sleep_millisecs_fd, "20", 2) <= 0)
return -errno;
return 0;
}
static void test_prctl_fork_exec(void)
{
int ret, status;
@ -500,6 +542,9 @@ static void test_prctl_fork_exec(void)
ksft_print_msg("[RUN] %s\n", __func__);
if (start_ksmd_and_set_frequency("2000", "0"))
ksft_test_result_fail("set ksmd's scanning frequency failed\n");
ret = prctl(PR_SET_MEMORY_MERGE, 1, 0, 0, 0);
if (ret < 0 && errno == EINVAL) {
ksft_test_result_skip("PR_SET_MEMORY_MERGE not supported\n");
@ -542,6 +587,11 @@ static void test_prctl_fork_exec(void)
return;
}
if (stop_ksmd_and_restore_frequency()) {
ksft_test_result_fail("restore ksmd frequency failed\n");
return;
}
ksft_test_result_pass("PR_SET_MEMORY_MERGE value is inherited\n");
}
@ -656,6 +706,13 @@ static void init_global_file_handles(void)
ksft_exit_skip("open(\"/proc/self/pagemap\") failed\n");
if (ksm_get_self_merging_pages() < 0)
ksft_exit_skip("accessing \"/proc/self/ksm_merging_pages\") failed\n");
pages_to_scan_fd = open("/sys/kernel/mm/ksm/pages_to_scan", O_RDWR);
if (pages_to_scan_fd < 0)
ksft_exit_fail_msg("opening /sys/kernel/mm/ksm/pages_to_scan failed\n");
sleep_millisecs_fd = open("/sys/kernel/mm/ksm/sleep_millisecs", O_RDWR);
if (sleep_millisecs_fd < 0)
ksft_exit_fail_msg("opening /sys/kernel/mm/ksm/sleep_millisecs failed\n");
}
int main(int argc, char **argv)