Re: [patch 5/5] oom: invoke OOM killer from pagefault handler

Andrew Morton
2006-10-12T22:10:24Z

On Thu, 12 Oct 2006 17:19:07 +0200
Nick Piggin <npiggin@suse.de> wrote:

> On Thu, Oct 12, 2006 at 07:12:13PM +0400, Kirill Korotaev wrote:
> > Nick,
> >
> > AFAICS, 1 page allocation which is done in page fault handler
> > can fail in the only case - OOM kills current, so if we failed
> > we should have TIF_MEMDIE and just kill current.
> > Selecting another process for killing if page fault fails means
> > taking another victim with the one being already killed.
> >
>
> Hi Kirill,
>
> I don't quite understand you.

Kirill is claiming that the only occasion on which a pagefault handler would
get an oom is when it killed itself in the oom handler.

> If the page allocation fails in the
> fault handler, we don't want to kill current if it is marked as
> OOM_DISABLE or sysctl_panic_on_oom is set... imagine a critical
> service in a failover system.
>
> It should be quite likely for another process to be kiled and
> provide enough memory to keep the system running. Presuming you
> have faith in the concept of the OOM killer ;)

I'm a bit wobbly about this one. Some before-and-after testing results
would help things along..