Re: [PATCH 1/3 v4] resources: introduce generic page_is_ram()

Wu Fengguang
2010-01-27T03:07:09Z

On Tue, Jan 26, 2010 at 05:30:58PM -0700, Andrew Morton wrote:

> > +int __attribute__((weak)) page_is_ram(unsigned long pfn)
> > +{
> > + return walk_system_ram_range(pfn, 1, NULL, __is_ram) == 1;
> > +}
>
> I'll switch this to use __weak.

Thanks.

> > /*
> > * Find empty slot in the resource tree given range and alignment.
> > */
> > --- linux-mm.orig/include/linux/ioport.h 2010-01-22 11:20:34.000000000 +0800
> > +++ linux-mm/include/linux/ioport.h 2010-01-22 11:20:35.000000000 +0800
> > @@ -191,5 +191,7 @@ extern int
> > walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages,
> > void *arg, int (*func)(unsigned long, unsigned long, void *));
> >
> > +extern int page_is_ram(unsigned long pfn);
>
> Is it appropriate that this function be declared in ioport.h? It's a
> pretty general function. Dunno.

Good suggestion. The following patch moves it to mm.h.

> > #endif /* __ASSEMBLY__ */
> > #endif /* _LINUX_IOPORT_H */
> > --- linux-mm.orig/arch/score/mm/init.c 2010-01-22 11:20:34.000000000 +0800
> > +++ linux-mm/arch/score/mm/init.c 2010-01-22 11:20:35.000000000 +0800
> > @@ -59,7 +59,7 @@ static unsigned long setup_zero_page(voi
> > }
> >
> > #ifndef CONFIG_NEED_MULTIPLE_NODES
> > -static int __init page_is_ram(unsigned long pagenr)
> > +int page_is_ram(unsigned long pagenr)
> > {
> > if (pagenr >= min_low_pfn && pagenr < max_low_pfn)
> > return 1;
> > --- linux-mm.orig/arch/mips/mm/init.c 2010-01-22 11:20:34.000000000 +0800
> > +++ linux-mm/arch/mips/mm/init.c 2010-01-22 11:20:35.000000000 +0800
> > @@ -298,7 +298,7 @@ void __init fixrange_init(unsigned long
> > }
> >
> > #ifndef CONFIG_NEED_MULTIPLE_NODES
> > -static int __init page_is_ram(unsigned long pagenr)
> > +int page_is_ram(unsigned long pagenr)
> > {
> > int i;
>
> hm, so we lose the __init.

Maybe Ralf Baechle knows whether MIPS can switch to the (smaller)
generic page_is_ram().

Thanks,
Fengguang
---
move page_is_ram() declaration to mm.h

---
include/linux/ioport.h | 2 --
include/linux/mm.h | 2 ++
2 files changed, 2 insertions(+), 2 deletions(-)

--- linux-mm.orig/include/linux/ioport.h 2010-01-27 11:04:22.000000000 +0800
+++ linux-mm/include/linux/ioport.h 2010-01-27 11:04:38.000000000 +0800
@@ -191,7 +191,5 @@ extern int
walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages,
void *arg, int (*func)(unsigned long, unsigned long, void *));

-extern int page_is_ram(unsigned long pfn);
-
#endif /* __ASSEMBLY__ */
#endif /* _LINUX_IOPORT_H */
--- linux-mm.orig/include/linux/mm.h 2010-01-27 11:04:43.000000000 +0800
+++ linux-mm/include/linux/mm.h 2010-01-27 11:05:30.000000000 +0800
@@ -265,6 +265,8 @@ static inline int get_page_unless_zero(s
return atomic_inc_not_zero(&page->_count);
}

+extern int page_is_ram(unsigned long pfn);
+
/* Support for virtually mapped pages */
struct page *vmalloc_to_page(const void *addr);
unsigned long vmalloc_to_pfn(const void *addr);