Re: OOM killer firing on 2.6.18 and later during LTP runs

[Andrew Morton <akpm@osdl.org>]

On Sat, 25 Nov 2006 22:00:45 -0500
Dave Jones <davej@redhat.com> wrote:

> On Sat, Nov 25, 2006 at 01:28:28PM -0800, Andrew Morton wrote:
>  > On Sat, 25 Nov 2006 13:03:45 -0800
>  > "Martin J. Bligh" <mbligh@mbligh.org> wrote:
>  > 
>  > > On 2.6.18-rc7 and later during LTP:
>  > > http://test.kernel.org/abat/48393/debug/console.log
>  > 
>  > The traces are a bit confusing, but I don't actually see anything wrong
>  > there.  The machine has used up all swap, has used up all memory and has
>  > correctly gone and killed things.  After that, there's free memory again.
> 
> We covered this a month or two back.  For RHEL5, we've ended up
> reintroducing the oom killer prevention logic that we had up until
> circa 2.6.10.   It seemed that there exist circumstances where
> given a little more time, some memory hogging apps will run to completion
> allowing other allocators to succeed instead of being killed.

I _think_ what you're describing here is a false-positive oom-killing?  But
Martin appears to be hitting a genuine oom.

But it does appear that some changes are needed, because lots of things got
oom-killed.

I think.  Maybe not - there's no timestamping in those logs and it is of
course possible that we're seeing unrelated ooms which happened a long time
apart.

> For reference, here's the patch that Larry Woodman came up with
> for RHEL5.

gulp.