On Mon, Mar 16, 2026 at 03:44:14PM +0100, David Hildenbrand (Arm) wrote: > On 3/16/26 14:47, Breno Leitao wrote: > > On Mon, Mar 16, 2026 at 12:55:13PM +0000, Lorenzo Stoakes (Oracle) wrote: > >> On Mon, Mar 09, 2026 at 05:00:34AM -0700, Breno Leitao wrote: > >>> Add a shell-based selftest that exercises the full set of THP sysfs > >>> knobs: enabled (global and per-size anon), defrag, use_zero_page, > >>> hpage_pmd_size, shmem_enabled (global and per-size), shrink_underused, > >>> khugepaged/ tunables, and per-size stats files. > >>> > >>> Each writable knob is tested for valid writes, invalid-input rejection, > >>> idempotent writes, and mode transitions where applicable. All original > >>> values are saved before testing and restored afterwards. > >>> > >>> The test uses the kselftest KTAP framework (ktap_helpers.sh) for > >>> structured TAP 13 output, making results parseable by the kselftest > >>> harness. The test plan is printed at the end since the number of test > >>> points is dynamic (depends on available hugepage sizes and sysfs files). > >>> > >>> This is particularly useful for validating the refactoring of > >>> enabled_store() and anon_enabled_store() to use sysfs_match_string() > >>> and the new change_enabled()/change_anon_orders() helpers. > >>> > >>> Signed-off-by: Breno Leitao <[email protected]> > >> > >> The test is broken locally for me, returning error code 127. > >> > >> I do appreciate the effort here, so I'm sorry to push back negatively, but > >> I > >> feel a bash script here is pretty janky, and frankly if any of these > >> interfaces > >> were as broken as this it'd be a major failure that would surely get > >> picked up > >> far sooner elsewhere. > >> > >> So while I think this might be useful as a local test for your sysfs > >> interface > >> changes, I don't think this is really suited to the mm selftests. > > > > That is totally fine. This test is what I have been using to test the > > changes, and I decide to share it in case someone find it useful. > > > > Let's drop it. > > Out of interest, to we know why the test is failing for Lorenzo?
I really don't know, but, it sounds like ktap was not found? Then the first early-exit path hit: ktap_skip_all "..." # undefined → returns 127 exit "$KSFT_SKIP" # expands to: exit "" → exits with last $? = 127 > I agree that the test is a bit excessive, in particular when it comes to > invalid/idempotent values etc. I could see some value for testing > whether setting the modes keeps working, but also then I wonder if that > is really something we'll be changing frequently (and that breaks easily). yea, I make it very excessive, because there were some intrinsics in those sysfs that I was gettingit wrong when doing the intial conversion. So, the test is something that I trust now, and I found it useful when finding regressiosn. Is is something that will chagne frequently? probably not! That said, would you like to have a simplified/different version of this test?
