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

Andrew Morton
2010-01-27T00:33:11Z

On Fri, 22 Jan 2010 16:16:19 +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.
>
> v4: prefer plain 1 instead of PAGE_IS_RAM (H. Peter Anvin)
> v3: add comment (KAMEZAWA Hiroyuki)
> "AFAIK, this "System RAM" information has been used for kdump to
> grab valid memory area and seems good for the kernel itself."
> v2: add PAGE_IS_RAM macro (Am__rico Wang)
>
> CC: Chen Liqin <liqin.chen@sunplusct.com>
> CC: Lennox Wu <lennox.wu@gmail.com>
> CC: Ralf Baechle <ralf@linux-mips.org>
> CC: Am__rico Wang <xiyou.wangcong@gmail.com>
> CC: linux-mips@linux-mips.org
> CC: Yinghai Lu <yinghai@kernel.org>
> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
> ---
> arch/mips/mm/init.c | 2 +-
> arch/score/mm/init.c | 2 +-
> include/linux/ioport.h | 2 ++
> kernel/resource.c | 13 +++++++++++++
> 4 files changed, 17 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 16:12:55.000000000 +0800
> @@ -327,6 +327,19 @@ int walk_system_ram_range(unsigned long
>
> #endif
>
> +static int __is_ram(unsigned long pfn, unsigned long nr_pages, void *arg)
> +{
> + return 1;
> +}
> +/*
> + * This generic page_is_ram() returns true if specified address is
> + * registered as "System RAM" in iomem_resource list.
> + */
> +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.

> /*
> * 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.

> #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.