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* [PATCH] mm: Provide consistent declaration for num_poisoned_pages
@ 2018-02-26 23:09 Guenter Roeck
  2018-02-26 23:57 ` David Rientjes
  0 siblings, 1 reply; 3+ messages in thread
From: Guenter Roeck @ 2018-02-26 23:09 UTC (permalink / raw)
  To: Andrew Morton; +Cc: linux-mm, linux-kernel, Guenter Roeck, Matthias Kaehlcke

clang reports the following compile warning.

In file included from mm/vmscan.c:56:
./include/linux/swapops.h:327:22: warning:
	section attribute is specified on redeclared variable [-Wsection]
extern atomic_long_t num_poisoned_pages __read_mostly;
                     ^
./include/linux/mm.h:2585:22: note: previous declaration is here
extern atomic_long_t num_poisoned_pages;
                     ^

Let's use __read_mostly everywhere.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Cc: Matthias Kaehlcke <mka@chromium.org>
---
 include/linux/mm.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index ad06d42adb1a..bd4bd59f02c1 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2582,7 +2582,7 @@ extern int get_hwpoison_page(struct page *page);
 extern int sysctl_memory_failure_early_kill;
 extern int sysctl_memory_failure_recovery;
 extern void shake_page(struct page *p, int access);
-extern atomic_long_t num_poisoned_pages;
+extern atomic_long_t num_poisoned_pages __read_mostly;
 extern int soft_offline_page(struct page *page, int flags);
 
 
-- 
2.7.4

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^ permalink raw reply related	[flat|nested] 3+ messages in thread
* Re: [PATCH] mm: Provide consistent declaration for num_poisoned_pages
  2018-02-26 23:09 [PATCH] mm: Provide consistent declaration for num_poisoned_pages Guenter Roeck
@ 2018-02-26 23:57 ` David Rientjes
  2018-02-27  2:13   ` Guenter Roeck
  0 siblings, 1 reply; 3+ messages in thread
From: David Rientjes @ 2018-02-26 23:57 UTC (permalink / raw)
  To: Guenter Roeck; +Cc: Andrew Morton, linux-mm, linux-kernel, Matthias Kaehlcke

On Mon, 26 Feb 2018, Guenter Roeck wrote:

> clang reports the following compile warning.
> 
> In file included from mm/vmscan.c:56:
> ./include/linux/swapops.h:327:22: warning:
> 	section attribute is specified on redeclared variable [-Wsection]
> extern atomic_long_t num_poisoned_pages __read_mostly;
>                      ^
> ./include/linux/mm.h:2585:22: note: previous declaration is here
> extern atomic_long_t num_poisoned_pages;
>                      ^
> 
> Let's use __read_mostly everywhere.
> 
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
> Cc: Matthias Kaehlcke <mka@chromium.org>
> ---
>  include/linux/mm.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index ad06d42adb1a..bd4bd59f02c1 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -2582,7 +2582,7 @@ extern int get_hwpoison_page(struct page *page);
>  extern int sysctl_memory_failure_early_kill;
>  extern int sysctl_memory_failure_recovery;
>  extern void shake_page(struct page *p, int access);
> -extern atomic_long_t num_poisoned_pages;
> +extern atomic_long_t num_poisoned_pages __read_mostly;
>  extern int soft_offline_page(struct page *page, int flags);
>  
>  

No objection to the patch, of course, but I'm wondering if it's (1) the 
only such clang compile warning for mm/, and (2) if the re-declaration in 
mm.h could be avoided by including swapops.h?

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^ permalink raw reply	[flat|nested] 3+ messages in thread
* Re: [PATCH] mm: Provide consistent declaration for num_poisoned_pages
  2018-02-26 23:57 ` David Rientjes
@ 2018-02-27  2:13   ` Guenter Roeck
  0 siblings, 0 replies; 3+ messages in thread
From: Guenter Roeck @ 2018-02-27  2:13 UTC (permalink / raw)
  To: David Rientjes; +Cc: Andrew Morton, linux-mm, linux-kernel, Matthias Kaehlcke

On 02/26/2018 03:57 PM, David Rientjes wrote:
> On Mon, 26 Feb 2018, Guenter Roeck wrote:
> 
>> clang reports the following compile warning.
>>
>> In file included from mm/vmscan.c:56:
>> ./include/linux/swapops.h:327:22: warning:
>> 	section attribute is specified on redeclared variable [-Wsection]
>> extern atomic_long_t num_poisoned_pages __read_mostly;
>>                       ^
>> ./include/linux/mm.h:2585:22: note: previous declaration is here
>> extern atomic_long_t num_poisoned_pages;
>>                       ^
>>
>> Let's use __read_mostly everywhere.
>>
>> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
>> Cc: Matthias Kaehlcke <mka@chromium.org>
>> ---
>>   include/linux/mm.h | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/include/linux/mm.h b/include/linux/mm.h
>> index ad06d42adb1a..bd4bd59f02c1 100644
>> --- a/include/linux/mm.h
>> +++ b/include/linux/mm.h
>> @@ -2582,7 +2582,7 @@ extern int get_hwpoison_page(struct page *page);
>>   extern int sysctl_memory_failure_early_kill;
>>   extern int sysctl_memory_failure_recovery;
>>   extern void shake_page(struct page *p, int access);
>> -extern atomic_long_t num_poisoned_pages;
>> +extern atomic_long_t num_poisoned_pages __read_mostly;
>>   extern int soft_offline_page(struct page *page, int flags);
>>   
>>   
> 
> No objection to the patch, of course, but I'm wondering if it's (1) the
> only such clang compile warning for mm/, and (2) if the re-declaration in

It is the only one I recall seeing in mm/ while testing the clang/retpoline
changes with ToT clang 7.0.0, but then I didn't pay too close attention.

> mm.h could be avoided by including swapops.h?
> 

Another alternative would be to remove the extern fom swapops.h and have
swapops.h include mm.h instead. I chose the least invasive change since
I didn't want to risk breaking some other build (after all, maybe there
was a reason for declaring num_poisoned_pages in two include files).

Guenter

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^ permalink raw reply	[flat|nested] 3+ messages in thread
end of thread, other threads:[~2018-02-27  2:14 UTC | newest]

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2018-02-26 23:09 [PATCH] mm: Provide consistent declaration for num_poisoned_pages Guenter Roeck
2018-02-26 23:57 ` David Rientjes
2018-02-27  2:13   ` Guenter Roeck

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