On Tue, 2013-06-18 at 22:31 +0800, Zhang Yanfei wrote:
> From: Zhang Yanfei <zhangyanfei@xxxxxxxxxxxxxx>
>
> With CONFIG_MEMORY_HOTREMOVE unset, there is a compile warning:
>
> mm/sparse.c:755: warning: ‘clear_hwpoisoned_pages’ defined but not used
>
> And Bisecting it ended up pointing to:
>
> commit 4edd7ceff0662afde195da6f6c43e7cbe1ed2dc4
> Author: David Rientjes <rientjes@xxxxxxxxxx>
> Date: Mon Apr 29 15:08:22 2013 -0700
>
> mm, hotplug: avoid compiling memory hotremove functions when disabled
>
> __remove_pages() is only necessary for CONFIG_MEMORY_HOTREMOVE. PowerPC
> pseries will return -EOPNOTSUPP if unsupported.
>
> Adding an #ifdef causes several other functions it depends on to also
> become unnecessary, which saves in .text when disabled (it's disabled in
> most defconfigs besides powerpc, including x86). remove_memory_block()
> becomes static since it is not referenced outside of
> drivers/base/memory.c.
>
> Build tested on x86 and powerpc with CONFIG_MEMORY_HOTREMOVE both enabled
> and disabled.
>
> Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx>
> Acked-by: Toshi Kani <toshi.kani@xxxxxx>
> Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
> Cc: Paul Mackerras <paulus@xxxxxxxxx>
> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> Cc: Wen Congyang <wency@xxxxxxxxxxxxxx>
> Cc: Tang Chen <tangchen@xxxxxxxxxxxxxx>
> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx>
> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
>
> This is because the commit above put function sparse_remove_one_section
> within the protection of CONFIG_MEMORY_HOTREMOVE but the only user of
> function clear_hwpoisoned_pages is sparse_remove_one_section, and it
> is not within the protection of CONFIG_MEMORY_HOTREMOVE.
>
> So put clear_hwpoisoned_pages within CONFIG_MEMORY_HOTREMOVE should
> fix the warning.
>
> Signed-off-by: Zhang Yanfei <zhangyanfei@xxxxxxxxxxxxxx>
> Cc: David Rientjes <rientjes@xxxxxxxxxx>
> Cc: Toshi Kani <toshi.kani@xxxxxx>
Looks good.
Acked-by: Toshi Kani <toshi.kani@xxxxxx>
Thanks,
-Toshi
> mm/sparse.c | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/mm/sparse.c b/mm/sparse.c
> index 1c91f0d..999a1fe 100644
> --- a/mm/sparse.c
> +++ b/mm/sparse.c
> @@ -751,6 +751,7 @@ out:
> return ret;
> }
>
> +#ifdef CONFIG_MEMORY_HOTREMOVE
> #ifdef CONFIG_MEMORY_FAILURE
> static void clear_hwpoisoned_pages(struct page *memmap, int nr_pages)
> {
> @@ -772,7 +773,6 @@ static inline void clear_hwpoisoned_pages(struct page *memmap, int nr_pages)
> }
> #endif
>
> -#ifdef CONFIG_MEMORY_HOTREMOVE
> static void free_section_usemap(struct page *memmap, unsigned long *usemap)
> {
> struct page *usemap_page;
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