On 2016/9/14 19:29, Tetsuo Handa wrote: > On 2016/09/14 18:25, zhong jiang wrote: >> On 2016/9/14 16:52, Michal Hocko wrote: >>> On Wed 14-09-16 10:42:19, Michal Hocko wrote: >>>> [Let's CC Hugh] >>> now for real... >>> >>>> On Wed 14-09-16 15:13:50, zhong jiang wrote: >>>> [...] >>>>> hi, Michal >>>>> >>>>> Recently, I hit the same issue when run a OOM case of the LTP and ksm enable. >>>>> >>>>> [ 601.937145] Call trace: >>>>> [ 601.939600] [<ffffffc000086a88>] __switch_to+0x74/0x8c >>>>> [ 601.944760] [<ffffffc000a1bae0>] __schedule+0x23c/0x7bc >>>>> [ 601.950007] [<ffffffc000a1c09c>] schedule+0x3c/0x94 >>>>> [ 601.954907] [<ffffffc000a1eb84>] rwsem_down_write_failed+0x214/0x350 >>>>> [ 601.961289] [<ffffffc000a1e32c>] down_write+0x64/0x80 >>>>> [ 601.966363] [<ffffffc00021f794>] __ksm_exit+0x90/0x19c >>>>> [ 601.971523] [<ffffffc0000be650>] mmput+0x118/0x11c >>>>> [ 601.976335] [<ffffffc0000c3ec4>] do_exit+0x2dc/0xa74 >>>>> [ 601.981321] [<ffffffc0000c46f8>] do_group_exit+0x4c/0xe4 >>>>> [ 601.986656] [<ffffffc0000d0f34>] get_signal+0x444/0x5e0 >>>>> [ 601.991904] [<ffffffc000089fcc>] do_signal+0x1d8/0x450 >>>>> [ 601.997065] [<ffffffc00008a35c>] do_notify_resume+0x70/0x78 > Please be sure to include exact kernel version (e.g. "uname -r", > "cat /proc/version") when reporting. > > You are reporting a bug in 4.1-stable kernel, which was prone to > OOM livelock because the OOM reaper is not available. > ( http://lkml.kernel.org/r/57D8012F.7080508@xxxxxxxxxx ) > > I think we no longer can reproduce this bug using 4.8-rc6 (or linux-next), > but it will be a nice thing to backport __GFP_NORETRY patch to stable > kernels which do not have the OOM reaper. No, OOM reaper can not solve the issue completely , As had disscussed with Michal. The conclusion is that we need come up with a better method to fix it. Thanks zhongjiang >> Adding the __GFP_NORETRY, the issue also can fixed. >> Therefore, we can assure that the case of LTP will leads to the endless looping. >> >> index d45a0a1..03fb67b 100644 >> --- a/mm/ksm.c >> +++ b/mm/ksm.c >> @@ -283,7 +283,7 @@ static inline struct rmap_item *alloc_rmap_item(void) >> { >> struct rmap_item *rmap_item; >> >> - rmap_item = kmem_cache_zalloc(rmap_item_cache, GFP_KERNEL); >> + rmap_item = kmem_cache_zalloc(rmap_item_cache, GFP_KERNEL | __GFP_NORETRY); >> if (rmap_item) >> ksm_rmap_items++; >> return rmap_item; > > . > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>