Re: BUG: Slowdown on 3000 socket-machines tracked down

Andrew Morton
2005-03-10T09:10:48Z

Andi Kleen <ak@muc.de> wrote:
>
> In general to solve it one has to increase /proc/sys/vm/freepages
> a lot.

/proc/sys/vm/min_free_kbytes

> It would be nice though if the VM tuned itself dynamically to a lot
> of GFP_ATOMIC requests. And maybe if GFP_ATOMIC was a bit more aggressive
> and did some simple minded reclaiming that would be helpful too.
> e.g. there could be a "easy to free" list in the VM for clean pages
> where freeing is simple enough that it could be made interrupt safe.

I spose we could autotune the free memory thresholds somehow, if there is
good reason and a testcase.

Or we could run page reclaim from hard IRQ context - that could be a bit
expensive in terms of CPU consumption and latency though.