Re: [PATCH] Prevent OOM from killing init

[Szabolcs Szakacsits]

On Wed, 21 Mar 2001, Rik van Riel wrote:
> One question ... has the OOM killer ever selected init on
> anybody's system ?

Hi Rik,

When I ported your OOM killer to 2.2.x and integrated it into the
'reserved root memory' [*] patch, during intensive testing I found two
cases when init was killed. It happened on low-end machines and when OOM
killer wasn't triggered so init was killed in the page fault handler.
The later was also one of the reasons I replaced the "random" OOM killer
in page fault handler with yours [so there is only one OOM killer]. I
also asked you at that time whether there was any reason you didn't put
it also there but unfortunately you didn't answer. Practice showed it
works there as well [and actually some crashes that was reported here
recently could have been avoided in this way] but technically maybe I
missed something?

Other things that bothered me,
 - niced processes are penalized
 - trying to kill a task that is permanently in TASK_UNINTERRUPTIBLE
   will probably deadlock the machine [or the random OOM killer will
   kill the box].

	Szaka

[*] who are interested, it can be found at
	http://mlf.linux.rulez.org/mlf/ezaz/reserved_root_memory.html