2013-06-18 14:31:57

by Zhang Yanfei

Subject: [PATCH] mm, sparse: Put clear_hwpoisoned_pages within CONFIG_MEMORY_HOTREMOVE

From: Zhang Yanfei <[email protected]>

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 <[email protected]>
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 <[email protected]>
Acked-by: Toshi Kani <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Wen Congyang <[email protected]>
Cc: Tang Chen <[email protected]>
Cc: Yasuaki Ishimatsu <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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 <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: Toshi Kani <[email protected]>
---
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;
--
1.7.1

2013-06-18 21:32:22

by Toshi Kani

Subject: Re: [PATCH] mm, sparse: Put clear_hwpoisoned_pages within CONFIG_MEMORY_HOTREMOVE

On Tue, 2013-06-18 at 22:31 +0800, Zhang Yanfei wrote:
> From: Zhang Yanfei <[email protected]>
>
> 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 <[email protected]>
> 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 <[email protected]>
> Acked-by: Toshi Kani <[email protected]>
> Cc: Benjamin Herrenschmidt <[email protected]>
> Cc: Paul Mackerras <[email protected]>
> Cc: Greg Kroah-Hartman <[email protected]>
> Cc: Wen Congyang <[email protected]>
> Cc: Tang Chen <[email protected]>
> Cc: Yasuaki Ishimatsu <[email protected]>
> Signed-off-by: Andrew Morton <[email protected]>
> Signed-off-by: Linus Torvalds <[email protected]>
>
> 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 <[email protected]>
> Cc: David Rientjes <[email protected]>
> Cc: Toshi Kani <[email protected]>

Looks good.

Acked-by: Toshi Kani <[email protected]>

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;