Messages in this thread |  | | Date | Mon, 18 Sep 2000 01:29:49 +0200 | From | Andrea Arcangeli <> | Subject | Re: Very aggressive swapping after 2 hours rest |
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On Sun, Sep 17, 2000 at 05:37:13PM -0300, Rik van Riel wrote: > Sysrq-M displays the info for my VM too, but you'll have to > admit that it isn't as useful as vmstat ;)
I agree about that info. That's an information not really relevant to the internal of the memory balancing algorithm, but it's an information that regards the state of the pagecache and that can tell how much RAM the system really needs to perform well.
Having only a few mbytes of cache "unmapped" is an issue, having to pagein/pageout all the time because the big cache had to be pagedin/pagedout is a completly different thing, so I think it would be useful to export to userspace such information as the number of pagecache pages that shouldn't be considered "free" (in your case it's the amount of Active pages).
Just to make the opposite example in the new VM there's a field that you said to report the net amount of allocations we get per second, averaged over one minute, that looks more an internal "memory" of the algorithm than something that can be useful to know to an administrator/developer. It's certainly fine to export it via /proc/meminfo as you did so we can monitor it easily in background and also a VM expert developer can look at with proper scripts in case he found something strange, but I'd prefer not to make generic userspace programs like vmstat to depend on it (tomorrow you may even choose to replace it with some more advanced thing or just to average it in two minutes instead of one minute or whatever else).
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