Stefan Roesch <shr@xxxxxxxxxxxx> writes: > David Hildenbrand <david@xxxxxxxxxx> writes: > >> On 16.11.23 05:39, kernel test robot wrote: >>> hi, Stefan Roesch, >>> we reported >>> "[linux-next:master] [mm/ksm] 5e924ff54d: ltp.ksm01_1.fail" >>> in >>> https://lore.kernel.org/all/202311031548.66780ff5-oliver.sang@xxxxxxxxx/ >>> when this commit is in linux-next/master. >>> now we noticed this commit is merged in mainline, and we still observed >>> same issue. just FYI. >>> Hello, >>> kernel test robot noticed "ltp.ksm01.fail" on: >>> commit: 5e924ff54d088828794d9f1a4d5bf17808f7270e ("mm/ksm: add "smart" page >>> scanning mode") >>> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master >>> [test failed on linus/master 3ca112b71f35dd5d99fc4571a56b5fc6f0c15814] >>> [test failed on linux-next/master 8728c14129df7a6e29188a2e737b4774fb200953] >>> in testcase: ltp >>> version: ltp-x86_64-14c1f76-1_20230715 >>> with following parameters: >>> disk: 1HDD >>> test: mm-00/ksm01 >>> compiler: gcc-12 >>> test machine: 8 threads 1 sockets Intel(R) Core(TM) i7-7700 CPU @ 3.60GHz (Kaby Lake) with 32G memory >>> (please refer to attached dmesg/kmsg for entire log/backtrace) >>> If you fix the issue in a separate patch/commit (i.e. not just a new version >>> of >>> the same patch/commit), kindly add following tags >>> | Reported-by: kernel test robot <oliver.sang@xxxxxxxxx> >>> | Closes: https://lore.kernel.org/oe-lkp/202311161132.13d8ce5a-oliver.sang@xxxxxxxxx >>> Running tests....... >>> <<<test_start>>> >>> tag=ksm01 stime=1699563923 >>> cmdline="ksm01" >>> contacts="" >>> analysis=exit >>> <<<test_output>>> >>> tst_kconfig.c:87: TINFO: Parsing kernel config '/proc/config.gz' >>> tst_test.c:1558: TINFO: Timeout per run is 0h 00m 30s >>> mem.c:422: TINFO: wait for all children to stop. >>> mem.c:388: TINFO: child 0 stops. >>> mem.c:388: TINFO: child 1 stops. >>> mem.c:388: TINFO: child 2 stops. >>> mem.c:495: TINFO: KSM merging... >>> mem.c:434: TINFO: resume all children. >>> mem.c:422: TINFO: wait for all children to stop. >>> mem.c:344: TINFO: child 1 continues... >>> mem.c:347: TINFO: child 1 allocates 128 MB filled with 'a' >>> mem.c:344: TINFO: child 2 continues... >>> mem.c:347: TINFO: child 2 allocates 128 MB filled with 'a' >>> mem.c:344: TINFO: child 0 continues... >>> mem.c:347: TINFO: child 0 allocates 128 MB filled with 'c' >>> mem.c:400: TINFO: child 1 stops. >>> mem.c:400: TINFO: child 0 stops. >>> mem.c:400: TINFO: child 2 stops. >>> ksm_helper.c:36: TINFO: ksm daemon takes 2s to run two full scans >>> mem.c:264: TINFO: check! >>> mem.c:255: TPASS: run is 1. >>> mem.c:255: TPASS: pages_shared is 2. >>> .... >>> mem.c:255: TPASS: pages_shared is 1. >>> mem.c:255: TPASS: pages_sharing is 98302. >>> mem.c:252: TFAIL: pages_volatile is not 0 but 1. <----- >>> mem.c:252: TFAIL: pages_unshared is not 1 but 0. <----- >> >> @Stefan, is this simply related to the new scanning optimization (skip and >> eventually not merge a pages within the "2 scans" windows, whereby previously, >> they would have gotten merged)? >> >> If so, we might just want to disable that optimization for that test case? >> >> Alternatively, maybe we have to wait for "more" scan cycles instead of only 2? > > I'd expect this is caused by "smart scan", where we can skip pages. > The best is probably to disable the smart scan feature for this test. > The smart scan feature can be disabled by: > > echo 0 > /sys/kernel/mm/ksm/smart_scan > > I'll have a look at it today. > If I disable "smart scan", the testcase completes successully. This is simply the case that for the testcase, it can "skip" a page (as the "smart scan" feature is enabled). The easiest fix is to disable smart scan for the ksm cases. I'll send an ltp patch a bit later to address this issue.
