Re: [PATCH 5/7] mm: rework reclaim_stat counters

[KAMEZAWA Hiroyuki]

On Fri, 02 Mar 2012 10:11:18 +0400
Konstantin Khlebnikov <khlebnikov@xxxxxxxxxx> wrote:

> KAMEZAWA Hiroyuki wrote:
> > On Wed, 29 Feb 2012 13:15:56 +0400
> > Konstantin Khlebnikov<khlebnikov@xxxxxxxxxx>  wrote:
> >
> >> Currently there is two types of reclaim-stat counters:
> >> recent_scanned (pages picked from from lru),
> >> recent_rotated (pages putted back to active lru).
> >> Reclaimer uses ratio recent_rotated / recent_scanned
> >> for balancing pressure between file and anon pages.
> >>
> >> But if we pick page from lru we can either reclaim it or put it back to lru, thus:
> >> recent_scanned == recent_rotated[inactive] + recent_rotated[active] + reclaimed
> >> This can be called "The Law of Conservation of Memory" =)
> >>
> > I'm sorry....where is the count for active->incative ?
> 
> If reclaimer deactivates page it will bump recent_rotated[LRU_INACTIVE_ANON/FILE],
> (if I understand your question right) recent_rotated[] now count each evictable lru independently
> 

Hm, then

	active -> active   : recent_rotated[active]   += 1 
	active -> inactive : recent_rotated[inacitve] += 1
	inactive->inactive : recent_rotated[inactive] += 1
	inactive->active   : recent_rotated[active]   += 1 ?

Ok, it seems rotated[active] + rotated[inactive] == scan.

Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>

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