On Fri, 3 Sep 1999 18:32:42 +0200 (CEST), Andrea Arcangeli
<andrea@suse.de> said:
> On Fri, 3 Sep 1999, Stephen C. Tweedie wrote:
>> Right now 2.3.16's kswapd doesn't check what kinds of memory are free.
> Wrong. It only frees the regular memory.
OK, that's better --- thanks for pointing me at that, I missed it first
time round.
So, what we are left with is just an unpredictable performance change,
not a GFP_ATOMIC lockup. That will be much easier to tune. kswapd
still may have to do more than this, though: the last time I did any
serious performance profiling on the vm stack, it showed up pretty
clearly that async swapout by kswapd was one of the most important
factors in sustaining high swapout throughput. If you don't have kswapd
acting in that capacity in high memory, we may well see reduced swap
throughput under load.
However, I guess that is less important on a 4G machine than on, say, my
laptop. :) It may still be a factor on machines running heavy
multi-user compute loads, though.
--Stephen
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