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

William Lee Irwin III
2004-08-28T21:54:11Z

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

-- wli