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

KAMEZAWA Hiroyuki
2010-01-22T04:13:51Z

On Fri, 22 Jan 2010 11:21:03 +0800
Wu Fengguang <fengguang.wu@intel.com> wrote:

> It's based on walk_system_ram_range(), for archs that don't have
> their own page_is_ram().
>
> The static verions in MIPS and SCORE are also made global.
>
> CC: Chen Liqin <liqin.chen@sunplusct.com>
> CC: Lennox Wu <lennox.wu@gmail.com>
> CC: Ralf Baechle <ralf@linux-mips.org>
> CC: Am辿rico Wang <xiyou.wangcong@gmail.com>
> CC: linux-mips@linux-mips.org
> CC: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> CC: Yinghai Lu <yinghai@kernel.org>
> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>

Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>

Maybe adding comment like this is good for reviewers..

"This page_is_ram() returns true if specified address is registered
as System RAM in io_resource list."

AFAIK, this "System RAM" information has been used for kdump to grab valid
memory area and seems good for the kernel itself.

Thanks,
-Kame

Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> ---
> arch/mips/mm/init.c | 2 +-
> arch/score/mm/init.c | 2 +-
> include/linux/ioport.h | 2 ++
> kernel/resource.c | 11 +++++++++++
> 4 files changed, 15 insertions(+), 2 deletions(-)
>
> --- linux-mm.orig/kernel/resource.c 2010-01-22 11:20:34.000000000 +0800
> +++ linux-mm/kernel/resource.c 2010-01-22 11:20:35.000000000 +0800
> @@ -327,6 +327,17 @@ int walk_system_ram_range(unsigned long
>
> #endif
>
> +#define PAGE_IS_RAM 24
> +static int __is_ram(unsigned long pfn, unsigned long nr_pages, void *arg)
> +{
> + return PAGE_IS_RAM;
> +}
> +int __attribute__((weak)) page_is_ram(unsigned long pfn)
> +{
> + return PAGE_IS_RAM == walk_system_ram_range(pfn, 1, NULL, __is_ram);
> +}
> +#undef PAGE_IS_RAM
> +
> /*
> * 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);
> +
> #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;
>
>
>
>