Re: Re: Re: Re: [RFC] PAGE_RW Should be added to PAGE_COPY ?

Re: Re: Re: Re: [RFC] PAGE_RW Should be added to PAGE_COPY ?

[Zhou Yingchao]

>
>I replied too hastily.  I've since looked back to your original mail
Thank you for your patience.
>(in which you do mention Infiniband as an example, which has now
>helped to jog my brain), and realized that I was misinterpreting
>what you meant by "user-level network driver".
>
>The problem, as I now see it, is precisely with do_wp_page()'s
>TestSetPageLocked, as you first said.
Yeah, I think you get it.  ^_^
>
>Yes, it would be good if we could do that check in some other,
>reliable way.  The problem is that can_share_swap_page has to
>check page_mapcount (and PageSwapCache) and page_swapcount in
>an atomic way: the page lock is what we have used to guard the
>movement between mapcount and swapcount.
>
>I'll try to think whether we can do that better,
>but not until next week.
Ok, I expect for good news.
>
>Hugh

Yingchao Zhou