I want to make kernel oom_killer run and provide the related log entries in dmesg.
I set the following settings
echo 1 > /proc/sys/vm/overcommit_memory
and tried to fill up the RAM to it's max, so that OOM_killer will come in picture and will kill the memory-hungry process. Though, it's killing the application but I can not see relevant message in dmesg ?
How can I see messages like:
[11686.040460] flasherav invoked oom-killer: gfp_mask=0x201da, order=0, oom_adj=0, oom_score_adj=0
[11686.040467] flasherav cpuset=/ mems_allowed=0
[11686.040472] Pid: 2859, comm: flasherav Not tainted 3.0.0-12-generic #20-Ubuntu
[11686.040476] Call Trace:
[11686.040488] [<c10e1c15>] dump_header.isra.7+0x85/0xc0
[11686.040493] [<c10e1e6c>] oom_kill_process+0x5c/0x80
[11686.040498] [<c10e225f>] out_of_memory+0xbf/0x1d0
[11686.040503] [<c10e6123>] __alloc_pages_nodemask+0x6c3/0x6e0
[11686.040509] [<c10e78d3>] ? __do_page_cache_readahead+0xe3/0x170
[11686.040514] [<c10e0fc8>] filemap_fault+0x218/0x390
[11686.040519] [<c1001c24>] ? __switch_to+0x94/0x1a0
[11686.040525] [<c10fb5ee>] __do_fault+0x3e/0x4b0
[11686.040530] [<c1069971>] ? enqueue_hrtimer+0x21/0x80
[11686.040535] [<c10fec2c>] handle_pte_fault+0xec/0x220
[11686.040540] [<c10fee68>] handle_mm_fault+0x108/0x210
[11686.040546] [<c152fa00>] ? vmalloc_fault+0xee/0xee
[11686.040551] [<c152fb5b>] do_page_fault+0x15b/0x4a0
[11686.040555] [<c1069a90>] ? update_rmtp+0x80/0x80
[11686.040560] [<c106a7b6>] ? hrtimer_start_range_ns+0x26/0x30
[11686.040565] [<c106aeaf>] ? sys_nanosleep+0x4f/0x60
[11686.040569] [<c152fa00>] ? vmalloc_fault+0xee/0xee
[11686.040574] [<c152cfcf>] error_code+0x67/0x6c
[11686.040580] [<c1520000>] ? reserve_backup_gdb.isra.11+0x26d/0x2c0
[11686.043598] [ 2657] 999 2657 6624 128 1 0 0 telepathy-indic
[11686.043602] [ 2659] 999 2659 2246 112 0 0 0 mission-control
[11686.043607] [ 2662] 999 2662 5431 346 1 0 0 gdu-notificatio
[11686.043612] [ 2664] 0 2664 3716 2392 0 0 0 mount.ntfs
[11686.043617] [ 2679] 999 2679 12453 197 1 0 0 zeitgeist-datah
[11686.043621] [ 2685] 999 2685 5196 1581 1 0 0 zeitgeist-daemo
[11686.043626] [ 2934] 999 2934 16305 710 0 0 0 gnome-terminal
[11686.043631] [ 2938] 999 2938 553 0 0 0 0 gnome-pty-helpe
[11686.043636] [ 2939] 999 2939 1814 406 0 0 0 bash
[11686.043641] Out of memory: Kill process 2603 (flasherav) score 761 or sacrifice child
[11686.043647] Killed process 2603 (flasherav) total-vm:1498536kB, anon-rss:721784kB, file-rss:4228kB
UPDATE: I modified the grub.cfg to remove "loglevel=0" from kernel line. But still no ring bell
Best Answer
The extra info that comes out from oom_kill.c uses
pr_warn()to output the messages. As such you need to set up your kernel to output warning messages.See this answer for the setting you need (hint: it's loglevel=4 or higher).