On 06/22/2011 02:10 AM, KAMEZAWA Hiroyuki wrote:
This is a famous fork-bomb problem.
Well, the classical fork-bomb would probably try to spawn an infinite
amount of processes, while the number of processes spawned by "make -j"
is limited to the amount of source files (200 in my reproduction Makefile)
and "make" will not restart any processes that got OOM-killed, so it
should terminate after a (not really long) while.
Don't you use your test set under some cpu cgroup ?
I use the "cpu" controller, too, but haven't seen adverse
effects from doing that so far.
Even in the situation of the livelock I reported, processes
of other users that do not try I/O get their fair share
of CPU time.
Then, you can stop oom-kill by echo 1> .../memory.oom_control.
All processes under memcg will be blocked. you can kill all process under memcg
by you hands.
Well, but automatic OOM-killing of the processes of the memory hog was exactly
the desired behaviour I was looking for :-)
echo 64M>/cgroup/test/memory.limit_in_bytes
echo 64M>/cgroup/test/memory.memsw.limit_in_bytes
64M is crazy small limit for make -j , I use 300M for my test...
Just as well, in our real-world use case, the limits are set both
to 16G (which still isn't enough for a "make -j" on our huge source tree),
I intentionally set a rather low limit for the test-Makefile because
I wanted to spare others from first having to write 16G of bogus
source-files to their local storage before the symptom can be reproduced.
and plesse see what hapeens when
echo 1> /memory.oom_control
When I do this before the "make -j", the make childs are stopped,
processes of other users proceed normally.
But of course this will let the user who did the "make -j" assume
the machine is just busy with the compilation, instead of telling
him "you used too much memory".
And further processes started by the same users will mysteriously
stop, too...
Then, waiting for some page bit...I/O of libc mapped pages ?
Hmm. it seems buggy behavior. Okay, I'll dig this.
Thanks a lot for investigating!
Regards,
Lutz Vieweg
--
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