Re: Page Replacement in 2.6.10

[Rahul Iyer <rni@xxxxxxxxxxxxxx>]

>  
>
> > 4. what is the difference between shrink_cache() and shrink_caches(). 
> > note the 's'
> >    
>
> Use ctags or cscope, and learn C ;)
>
> Honestly, by now you should have seen that shrink_caches()
> calls shrink_zone(), which calls shrink_cache() ...
>
>  
Sorry... that was a dumb question. My apologies.

I've almost gotten this figured out... except:
1. Are the active and inactive lists per zone?
From what i'm reading, it seems to be so... with struct zone having 
active_list and inactive_list and add_to_active_list() et al.adding to 
zone->active_list. Im pretty sure about this fact, but i'm not sure i 
understand it (the rationale behind splitting the global active/inactive 
lists per zone)

2. The current design allows kind of restricts to page cache to it's 
current active/inactive list form. Wouldn't it be better to generalize 
this? For example, something like

struct page_cache {
   struct list_head[MAX_LISTS];
   void (*add_to_cache)(struct page *p);
   void (*del_from_cache)(struct page *);
   void (*page_accessed)(struct page *);
};

In this way, one could have multiple page caches as desired, and could 
select at complie time or maybe eve boot time (via a kernel arg). Now, 
writing a new page replacement policy is as simple as implementing the 
above struct. Does this make any sense? Or am i missing the big picture?
Thanks in advance
Rahul



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