Re: User space out of memory approach

[Marcelo Tosatti <marcelo.tosatti@cyclades.com>]

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 ?