Re: Understanding page faults code in mm/memory.c

["Raghu R. Arur" <rra2002@aria.ncl.cs.columbia.edu>]

>
> > [3] in mm/memory.c, in do_wp_page, I am not sure what the
> > portion of code is about:
> >
> > // If old_page bit is not set, set it, and test.
> > if (!TryLockPage(old_page) {
> >
> >     // [QN:] I don't understand what can_share_swap_page() do
> >     // I tried tracing, but i still don't quite get it.
> >     int reuse = can_share_swap_page(old_page);
>
> Basically it'll determine if you are the only user of that swap page. If
> it returns true, it means that you are the last process to break COW on
> that page so just use it. Otherwise it'll fall through and a new page will
> be allocated.

   But when you put a page on to the swap cache will not the rss of the
address spage  decrease. if not then when will the rss value of the
address space change.

 thanks,
Raghu
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