On 03/08/2013 09:00 AM, Howard Chu wrote:
First obvious conclusion - kswapd is being too aggressive. When free memory hits the low watermark, the reclaim shrinks slapd down from 25GB to 18-19GB, while the page cache still contains ~7GB of unmapped pages. Ideally I'd like a tuning knob so I can say to keep no more than 2GB of unmapped pages in the cache. (And the desired effect of that would be to allow user processes to grow to 30GB total, in this case.) I mentioned this "unmapped page cache control" post already http://lwn.net/Articles/436010/ but it seems that the idea was ultimately rejected. Is there anything else similar in current kernels?
Sorry, I'm not aware of anything. I'm not a filesystem/vm guy though, so maybe there's something I don't know about.
I would have expected both posix_madvise(..POSIX_MADV_RANDOM) and swappiness to help, but it doesn't sound like they're working.
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