Hello, today I was testing some patch with Linus' kernel from today (commit 31555213f03bca37d2c02e10946296052f4ecfcd) and I rather easily tripped out-of-memory messages and processes got killed. The unusual thing I'm doing is that I'm using user-mode-linux and the started virtual machine has relatively low amount of memory (I was tripping OOM immediately with mem=64M or mem=128M, I could still hit it after a while with mem=256M). The load I was running was just "dd if=/dev/zero of=/tmp/file bs=128k". The backing filesystem was ext3. Now with older kernel (e.g. 3.1) running even with mem=64M was fine. Example of an OOM message: dd invoked oom-killer: gfp_mask=0x200da, order=0, oom_adj=0, oom_score_adj=0 Call Trace: 6ff5b868: [<602f550d>] _raw_spin_unlock+0x9/0xb 6ff5b878: [<6005ad53>] dump_header.clone.2+0xba/0x1b6 6ff5b8b8: [<6005af77>] oom_kill_process.clone.0+0x45/0x236 6ff5b928: [<6005b506>] out_of_memory+0x25c/0x305 6ff5b9a8: [<6005e563>] __alloc_pages_nodemask+0x558/0x5fd 6ff5ba08: [<60270a2b>] radix_tree_lookup_slot+0xe/0x10 6ff5ba88: [<60065933>] shmem_getpage_gfp+0x269/0x475 6ff5bb18: [<60065b72>] shmem_write_begin+0x33/0x35 6ff5bb28: [<60059fa4>] generic_file_buffered_write+0x132/0x28f 6ff5bbf8: [<6005a47a>] __generic_file_aio_write+0x379/0x3b5 6ff5bcb8: [<6005a53a>] generic_file_aio_write+0x84/0xdd 6ff5bd28: [<6007fb09>] do_sync_write+0xd1/0x10e 6ff5bdc8: [<600174c1>] segv+0x8f/0x24a 6ff5be58: [<6007fc0b>] vfs_write+0xc5/0x16d 6ff5be98: [<6007fd64>] sys_write+0x45/0x6c 6ff5bed8: [<60017e48>] handle_syscall+0x50/0x70 6ff5bef8: [<60024ae6>] userspace+0x320/0x3d6 6ff5bfc8: [<600151ac>] fork_handler+0x7d/0x84 Mem-Info: Normal per-cpu: CPU 0: hi: 90, btch: 15 usd: 0 active_anon:850 inactive_anon:59583 isolated_anon:0 active_file:0 inactive_file:16 isolated_file:0 unevictable:0 dirty:0 writeback:0 unstable:0 free:510 slab_reclaimable:540 slab_unreclaimable:461 mapped:0 shmem:59685 pagetables:111 bounce:0 Normal free:2040kB min:2032kB low:2540kB high:3048kB active_anon:3400kB inactive_anon:238332kB active_file:0kB inactive_file:64kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:258560kB mlocked:0kB dirty:0kB writeback:0kB mapped:0kB shmem:238740kB slab_reclaimable:2160kB slab_unreclaimable:1844kB kernel_stack:272kB pagetables:444kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:46434 all_unreclaimable? yes lowmem_reserve[]: 0 0 Normal: 498*4kB 4*8kB 1*16kB 0*32kB 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 2040kB 59701 total pagecache pages 0 pages in swap cache Swap cache stats: add 0, delete 0, find 0/0 Free swap = 0kB Total swap = 0kB 65536 pages RAM 3222 pages reserved 16 pages shared 61703 pages non-shared [ pid ] uid tgid total_vm rss cpu oom_adj oom_score_adj name [ 670] 0 670 1489 37 0 0 0 syslogd [ 676] 0 676 682 21 0 0 0 klogd [ 720] 0 720 5597 94 0 0 0 exim4 [ 725] 0 725 680 18 0 0 0 inetd [ 739] 0 739 2282 36 0 0 0 atd [ 745] 0 745 2890 47 0 0 0 cron [ 762] 0 762 6338 75 0 0 0 login [ 763] 0 763 6338 74 0 0 0 login [ 764] 0 764 2593 131 0 0 0 bash [ 772] 0 772 2590 129 0 0 0 bash [ 805] 0 805 1262 58 0 0 0 dd Out of memory: Kill process 670 (syslogd) score 1 or sacrifice child Killed process 670 (syslogd) total-vm:5956kB, anon-rss:148kB, file-rss:0kB I'd be suspecting new IO-less throttling code but from the OOM report it seems there are no dirty or writeback pages so that seems to speak against that theory. Honza -- Jan Kara <jack@xxxxxxx> SUSE Labs, CR -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>