Re: memo: mem+swap controller

[Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>]

On Fri, 1 Aug 2008 01:31:41 +0900 (JST), kamezawa.hiroyu@jp.fujitsu.com wrote:
> >> > > Following is state transition and counter handling design memo.
> >> > > This uses "3" counters to handle above conrrectly. If you have other lo
> gic,
> >> > > please teach me. (and blame me if my diagram is broken.)
> >> > > 
> >> > I don't think counting "disk swap" is good idea(global linux
> >> > dosen't count it).
> >> > Instead, I prefer counting "total swap"(that is swap entry).
> >> > 
> >> Maybe my illustration is bad. 
> >> 
> >> total_swap = swap_cache + disk_swap. Yes, I count swp_entry.
> >> But just divides it to on-memory or not.
> >> 
> >> This is just a state transition problem. When we counting only total_swap,
> >> we cannot avoid double counting of a swap_cache as memory and as swap.
> >> 
> >I agree.
> >My intention was not counting only total_swap, but counting both
> >total_swap and swap_cache.
> >
> At early stage of diaglam, I just added total_swap counter.
> (total_swap here means # of used swp_entry.)
> And failed to write diaglam ;( Maybe selection of counters was bad.
> 
> If just 2 counters are enough, it's better.
> 
I think so.

> Hmm..
> - on_memory .... # of pages used
> - disk_swap      .... # of swp_entry without SwapCache
> 
> limit_in_bytes ... limits on_memory
> total_limit    ... limits on_mempry + disk_swap.
> 
> can work ?
> 
Theoretically it works, I think.

But, one thing I'm wondering is how to distinguish
"swap_cache -> freed" and "disk_swap -> freed".

Anyway, I need more consideration.


Thanks,
Daisuke Nishimura.

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