Re: [Xen-ia64-devel] [Patch 4/4] [RFC] Xwindow: Modify pci_acpi_scan_root()

[Jun Kamada <kama@xxxxxxxxxxxxxx>]

On Tue, 5 Jun 2007 14:47:11 +0900
Isaku Yamahata <yamahata@xxxxxxxxxxxxx> wrote:

> On Tue, Jun 05, 2007 at 01:29:11PM +0900, Jun Kamada wrote:
> 
> > Could you explain more about the PAGE_SIZE optimization?
> > 
> > Current code merges overlapped address ranges without awareness of
> > PAGE_SIZE and page alignment. Merged address range should
> > be divided by PAGE_SIZE?
> 
> ioremap hypercall works in PAGE_SIZE unit so that we can safely
> enlarge the region to be page aligned.
> What I wanted to suggest is somthing like the followings.
> (I assume that end is inclusive. If wrong, please correct it.)
> 
> static int
> __add_issue_list(unsigned long start, unsigned long end,
>                 ioremap_issue_list_t *top)
> ...
> -       new->start = start;
> -       new->end   = end;
> +       new->start = start & ~(PAGE_SIZE - 1);
> +       new->end   = end | (PAGE_SIZE - 1);

I understand. I will modify my code according to your comment.

Thank you so much.

-----
Jun Kamada
Virtual Systems Development Div.
Platform Technology Development Unit
Fujitsu Ltd.
kama@xxxxxxxxxxxxxx



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