On 12.04.23 05:16, Stefan Roesch wrote:
This adds three new tests to the selftests for KSM. These tests use the
new prctl API's to enable and disable KSM.
1) add new prctl flags to prctl header file in tools dir
This adds the new prctl flags to the include file prct.h in the
tools directory. This makes sure they are available for testing.
2) add KSM prctl merge test
This adds the -t option to the ksm_tests program. The -t flag
allows to specify if it should use madvise or prctl ksm merging.
3) add KSM get merge type test
This adds the -G flag to the ksm_tests program to query the KSM
status with prctl after KSM has been enabled with prctl.
4) add KSM fork test
Add fork test to verify that the MMF_VM_MERGE_ANY flag is inherited
by the child process.
5) add two functions for debugging merge outcome
This adds two functions to report the metrics in /proc/self/ksm_stat
and /sys/kernel/debug/mm/ksm.
The debugging can be enabled with the following command line:
make -C tools/testing/selftests TARGETS="mm" --keep-going \
EXTRA_CFLAGS=-DDEBUG=1
Would it make sense to instead have a "-D" (if still unused) runtime
options to print this data? Dead code that's not compiled is a bit
unfortunate as it can easily bit-rot.
This patch essentially does two things
1) Add the option to run all tests/benchmarks with the PRCTL instead of
MADVISE
2) Add some functional KSM tests for the new PRCTL (fork, enabling
works, disabling works).
The latter should rather go into ksm_functional_tests().
[...]
-static int check_ksm_unmerge(int mapping, int prot, int timeout, size_t page_size)
+/* Verify that prctl ksm flag is inherited. */
+static int check_ksm_fork(void)
+{
+ int rc = KSFT_FAIL;
+ pid_t child_pid;
+
+ if (prctl(PR_SET_MEMORY_MERGE, 1)) {
+ perror("prctl");
+ return KSFT_FAIL;
+ }
+
+ child_pid = fork();
+ if (child_pid == 0) {
+ int is_on = prctl(PR_GET_MEMORY_MERGE, 0);
+
+ if (!is_on)
+ exit(KSFT_FAIL);
+
+ exit(KSFT_PASS);
+ }
+
+ if (child_pid < 0)
+ goto out;
+
+ if (waitpid(child_pid, &rc, 0) < 0)
+ rc = KSFT_FAIL;
+
+ if (prctl(PR_SET_MEMORY_MERGE, 0)) {
+ perror("prctl");
+ rc = KSFT_FAIL;
+ }
+
+out:
+ if (rc == KSFT_PASS)
+ printf("OK\n");
+ else
+ printf("Not OK\n");
+
+ return rc;
+}
+
+static int check_ksm_get_merge_type(void)
+{
+ if (prctl(PR_SET_MEMORY_MERGE, 1)) {
+ perror("prctl set");
+ return 1;
+ }
+
+ int is_on = prctl(PR_GET_MEMORY_MERGE, 0);
+
+ if (prctl(PR_SET_MEMORY_MERGE, 0)) {
+ perror("prctl set");
+ return 1;
+ }
+
+ int is_off = prctl(PR_GET_MEMORY_MERGE, 0);
+
+ if (is_on && is_off) {
+ printf("OK\n");
+ return KSFT_PASS;
+ }
+
+ printf("Not OK\n");
+ return KSFT_FAIL;
+}
Yes, these two are better located in ksm_functional_tests() to just run
them both automatically when the test is executed.
--
Thanks,
David / dhildenb
