Re: User space out of memory approach

Marcelo Tosatti
2005-01-10T22:46:31Z

On Mon, Jan 10, 2005 at 05:20:13PM -0200, Marcelo Tosatti wrote:
> On Mon, Jan 10, 2005 at 05:43:23PM -0400, Mauricio Lin wrote:
> > Hi all,
> >
> > We have done a comparison between the kernel version and user space
> > version and apparently the behavior is similar. You can also get this
> > patch and module to test it and compare with kernel OOM Killer. Here
> > goes a patch and a module that moves the kernel space OOM Killer
> > algorithm to user space. Let us know about your ideas.
>
> No comments on the code itself - It is interesting to have certain pids "not selectable" by
> the OOM killer. Patches which have similar funcionality have been floating around.
>
> The userspace OOM killer is dangerous though. You have to guarantee that allocations
> will NOT happen until the OOM killer is executed and the killed process is dead and
> has its pages freed - allocations under OOM can cause deadlocks.
>
> "OOM-killer-in-userspace" is unreliable, not sure if its worth the effort making
> it reliable (mlock it, flagged as PF_MEMALLOC, etc).

Actually its only unreliable if its called from OOM time.

The case here is you have a daemon which periodically writes
to /proc/oom ?