Michal Hocko wrote: > On Fri 17-11-17 19:38:01, Tetsuo Handa wrote: > [...] > > [ 1792.835056] Out of memory: Kill process 14294 (idle-priority) score 876 or sacrifice child > > [ 1792.836073] Killed process 14458 (normal-priority) total-vm:4176kB, anon-rss:88kB, file-rss:0kB, shmem-rss:0kB > > Wen you are in a situation when you are killing 88kB process then you > are most probably going to suffer more oom kills anyway. Optimizing for > this case is thus questionable at best. You would need to come up with > a reasonable explanation why the livelock as described by Andrea is not > possible with the current MM reclaim retry implementation. I am not > saying the patch is wrong but your justification _is_ wrong. What I wanted you to check is the fact that there was about 1.5 seconds of time window and free: was 948KB above min: watermark (which is larger than 88KB) and total free was 1560KB above min: (which means that making free memory was in progress rather than suffer more OOM kills). [ 1792.835056] Out of memory: Kill process 14294 (idle-priority) score 876 or sacrifice child [ 1792.836073] Killed process 14458 (normal-priority) total-vm:4176kB, anon-rss:88kB, file-rss:0kB, shmem-rss:0kB [ 1792.837757] oom_reaper: reaped process 14458 (normal-priority), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB [ 1794.366070] systemd-journal invoked oom-killer: gfp_mask=0x14200ca(GFP_HIGHUSER_MOVABLE), nodemask=(null), order=0, oom_score_adj=0 (...snipped...) [ 1794.366295] Normal free:18448kB min:17500kB low:21872kB high:26244kB active_anon:650740kB inactive_anon:18976kB active_file:220kB inactive_file:436kB unevictable:0kB writepending:0kB present:1048576kB managed:966968kB mlocked:0kB kernel_stack:19568kB pagetables:36132kB bounce:0kB free_pcp:2736kB local_pcp:680kB free_cma:0kB (...snipped...) [ 1794.366342] Normal: 557*4kB (UM) 476*8kB (UMH) 126*16kB (UMH) 84*32kB (UM) 16*64kB (UM) 9*128kB (UM) 4*256kB (UM) 4*512kB (UM) 3*1024kB (M) 0*2048kB 0*4096kB = 19060kB (...snipped...) [ 1794.366368] Out of memory: Kill process 14294 (idle-priority) score 876 or sacrifice child [ 1794.367372] Killed process 14459 (normal-priority) total-vm:4176kB, anon-rss:88kB, file-rss:0kB, shmem-rss:0kB [ 1794.369143] oom_reaper: reaped process 14459 (normal-priority), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB But since I can't find better justification for this patch, I decided to send remaining patches first: http://lkml.kernel.org/r/1511607169-5084-1-git-send-email-penguin-kernel@xxxxxxxxxxxxxxxxxxx . -- 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>
