Re: freeing pagecache

[David Chow <davidchow@shaolinmicro.com>]

Matthew Wilcox wrote:

>On Sun, Sep 29, 2002 at 08:00:36PM +0800, David Chow wrote:
>  
>
>>cache... The reason I am asking the question is that if I am safe to 
>>make use of an unlocked mapped pagecahed page. Thanks for comments and 
>>answers.
>>    
>>
>
>You don't need to lock it, just bump its page count.  include/linux/mm.h:
>
> * Also, many kernel routines increase the page count before a critical
> * routine so they can be sure the page doesn't go away from under them.
> */
>#define get_page(p)             atomic_inc(&(p)->count)
>#define put_page(p)             __free_page(p)
>
>  
>


I've read about the struct page, I thought it is some kind of lru 
algorithm used by kswapd, that measn pagecache is just like dcache which 
has usage counts. There are a couple listhead, is there any listhead 
that are not used for a pagecached page? If there are something that I 
can make use, I can simply use the listhead for my list... but I am not 
sure are there any potential hazards. Thanks for helps, comments are 
welcome.

David