Re: User space out of memory approach

Mauricio Lin
2005-01-10T23:33:08Z

On Mon, 10 Jan 2005 18:05:14 -0200, Marcelo Tosatti
<marcelo.tosatti@cyclades.com> wrote:
> On Tue, Jan 11, 2005 at 12:40:24AM +0200, Edjard Souza Mota wrote:
> > Hi,
> >
> > I guess it the idea was not fully and well explained. It is not the OOM Killer
> > itself that was moved to user space but rather its ranking algorithm.
> > Ranking is not an specific functionality of kernel space. Kernel only need
> > to know which process whould be killed.
> >
> > In that sense the approach is different and might be worth testing, mainly for
> > cases where we want to allow better policies of ranking. For example, an
> > embedded device with few resources and important different running applications:
> > whic one is the best? To my understanding the current ranking policy
> > does not necessarily chooses the best one to be killed.
>
> Sorry, I misunderstood. Should have read the code before shouting.
>
> The feature is interesting - several similar patches have been around with similar
> functionality (people who need usually write their own, I've seen a few), but none
> has ever been merged, even though it is an important requirement for many users.
>
> This is simple, an ordered list of candidate PIDs. IMO something similar to this
> should be merged. Andrew ?
>
> Few comments about the code:
>
> retry:
> - p = select_bad_process();
> + printk(KERN_DEBUG "A good walker leaves no tracks.\n");
> + p = select_process();
>
> You want to fallback to select_bad_process() if no candidate has been selected at
> select_process().
The idea is turn off the select_bad_process() and the new
select_process() will get the list of pids to be killed from
/proc/oom. But the ranking algorithms is the same, I mean is the Rik
van Riel algorithm. Do you think it is worthwhile to maintain the
select_bad_process (kernel space algorithm) if we have the
select_process() function?

>
> You also want to move "oom" to /proc/sys/vm/.

This can be possible. Do you think that it is a good place to move the oom?

BR,

Mauricio Lin.