Hi Stefan, > This disables the "smart scan" KSM feature to make sure that the volatile > count remains at 0. > Signed-off-by: Stefan Roesch <devkernel.io> nit: you forgot 'shr@' Signed-off-by: Stefan Roesch <shr@xxxxxxxxxxxx> > Reported-by: kernel test robot <oliver.sang@xxxxxxxxx> > Closes: https://lore.kernel.org/oe-lkp/202311161132.13d8ce5a-oliver.sang@xxxxxxxxx > --- > testcases/kernel/mem/lib/mem.c | 4 ++++ > 1 file changed, 4 insertions(+) > diff --git a/testcases/kernel/mem/lib/mem.c b/testcases/kernel/mem/lib/mem.c > index fbfeef026..ef274a3ac 100644 > --- a/testcases/kernel/mem/lib/mem.c > +++ b/testcases/kernel/mem/lib/mem.c > @@ -454,6 +454,9 @@ void create_same_memory(int size, int num, int unit) > {'a', size*MB}, {'a', size*MB}, {'d', size*MB}, {'d', size*MB}, > }; > + /* Disable smart scan for correct volatile counts. */ > + SAFE_FILE_PRINTF(PATH_KSM "smart_scan", "0"); NOTE, this fails on the systems without /sys/kernel/mm/ksm/smart_scan: mem.c:458: TBROK: Failed to open FILE '/sys/kernel/mm/ksm/smart_scan' for writing: EACCES (13) NOTE, we normally handle the setup like this in test setup function. But new API has .save_restore which is more robust for tasks like this. It's already used in ksm01.c, you need just to add this line: {"/sys/kernel/mm/ksm/smart_scan", "0", TST_SR_SKIP}, (instead of both SAFE_FILE_PRINTF) See: https://github.com/linux-test-project/ltp/wiki/C-Test-API#127-saving--restoring-procsys-values I wonder if ksm01.c is the only ksm test which needs to disable this. also nit: there is a wrong indent (spaces instead of tabs), please be consistent with the file content. NOTE: while this fixes problem on 6.7.0-rc1-2.g86e46c2-default (openSUSE), it does not fixes other problem on 6.5.10 on Debian (16 errors like these below): mem.c:252: TFAIL: pages_shared is not 2 but 5038. mem.c:252: TFAIL: pages_sharing is not 98302 but 593629. mem.c:252: TFAIL: pages_volatile is not 0 but 391. mem.c:252: TFAIL: pages_unshared is not 0 but 149157. I have no idea if this is a real bug which needs to be fixed or test false positive to be fixed, or whether the problem has already been fixed in newer kernels. > + > ps = sysconf(_SC_PAGE_SIZE); > pages = MB / ps; > @@ -526,6 +529,7 @@ void create_same_memory(int size, int num, int unit) > tst_res(TINFO, "stop KSM."); > SAFE_FILE_PRINTF(PATH_KSM "run", "0"); > + SAFE_FILE_PRINTF(PATH_KSM "smart_scan", "1"); nit: Again, wrong indent. You could have seen it also in the generated patch. Kind regards, Petr > final_group_check(0, 0, 0, 0, 0, 0, size * pages * num); > while (waitpid(-1, &status, 0) > 0) > base-commit: 8c89ef3d451087ed6e18750bd5eedd10e5ab3d2e
