Re: Kernel 2.6.8.1: swap storm of death - nr_requests > 1024 on swap partition

Andrew Morton
2004-08-28T22:13:49Z

William Lee Irwin III <wli@holomorphy.com> wrote:
>
> Karl Vogel <karl.vogel@pandora.be> wrote:
> >> With overcommit_memory set to 1, the program can be run again after the
> >> OOM kill.. but the OOM killing remains.
> >> With overcommit_memory set to 0 a second run fails. I 'think' it's
> >> because somehow SwapCache is 500Kb after the OOM, so in effect my system
> >> doesn't have 1Gb to spare anymore. Doing swapoff/swapon frees this and
> >> then I can do the calloc(1Gb) again.
> >> Another way to free the SwapCached is to generate lots of I/O doing 'dd
> >> if=/dev/hda of=/dev/null' ... after a while SwapCached is < 1Mb again.
>
> On Sat, Aug 28, 2004 at 02:43:03PM -0700, Andrew Morton wrote:
> > urgh. It sounds like the overcommit logic forgot to account swapcache as
> > reclaimable. It's been a ton of trouble, that code.
>
> For overcommit purposes, swapcache still counts as committed AS; it
> requires swap as backing store to evict. So AFAICT there isn't an issue
> there.

But that backing store is allocated?

> I was under the impression this had something to do with IO
> schedulers.

Separate issue.