On 11/15/18 at 03:32pm, Michal Hocko wrote: > On Thu 15-11-18 21:38:40, Baoquan He wrote: > > On 11/15/18 at 02:19pm, Michal Hocko wrote: > > > On Thu 15-11-18 21:12:11, Baoquan He wrote: > > > > On 11/15/18 at 09:30am, Michal Hocko wrote: > > > [...] > > > > > It would be also good to find out whether this is fs specific. E.g. does > > > > > it make any difference if you use a different one for your stress > > > > > testing? > > > > > > > > Created a ramdisk and put stress bin there, then run stress -m 200, now > > > > seems it's stuck in libc-2.28.so migrating. And it's still xfs. So now xfs > > > > is a big suspect. At bottom I paste numactl printing, you can see that it's > > > > the last 4G. > > > > > > > > Seems it's trying to migrate libc-2.28.so, but stress program keeps trying to > > > > access and activate it. > > > > > > Is this still with faultaround disabled? I have seen exactly same > > > pattern in the bug I am working on. It was ext4 though. > > > > After a long time struggling, the last 2nd block where libc-2.28.so is > > located is reclaimed, now it comes to the last memory block, still > > stress program itself. swap migration entry has been made and trying to > > unmap, now it's looping there. > > > > [ +0.004445] migrating pfn 190ff2bb0 failed > > [ +0.000013] page:ffffea643fcaec00 count:203 mapcount:201 mapping:ffff888dfb268f48 index:0x0 > > [ +0.012809] shmem_aops > > [ +0.000011] name:"stress" > > [ +0.002550] flags: 0x1dfffffc008004e(referenced|uptodate|dirty|workingset|swapbacked) > > [ +0.010715] raw: 01dfffffc008004e ffffea643fcaec48 ffffea643fc714c8 ffff888dfb268f48 > > [ +0.007828] raw: 0000000000000000 0000000000000000 000000cb000000c8 ffff888e72e92000 > > [ +0.007810] page->mem_cgroup:ffff888e72e92000 > [...] > > [ +0.004455] migrating pfn 190ff2bb0 failed > > [ +0.000018] page:ffffea643fcaec00 count:203 mapcount:201 mapping:ffff888dfb268f48 index:0x0 > > [ +0.014392] shmem_aops > > [ +0.000010] name:"stress" > > [ +0.002565] flags: 0x1dfffffc008004e(referenced|uptodate|dirty|workingset|swapbacked) > > [ +0.010675] raw: 01dfffffc008004e ffffea643fcaec48 ffffea643fc714c8 ffff888dfb268f48 > > [ +0.007819] raw: 0000000000000000 0000000000000000 000000cb000000c8 ffff888e72e92000 > > [ +0.007808] page->mem_cgroup:ffff888e72e92000 > > OK, so this is tmpfs backed code of your stree test. This just tells us > that this is not fs specific. Reference count is 2 more than the map > count which is the expected state. So the reference count must have been > elevated at the time when the migration was attempted. Shmem supports > fault around so this might be still possible (assuming it is enabled). > If not we really need to dig deeper. I will think of a debugging patch. Yes, faultaround is enabled. Will disable it and test again. Will report test result.
