* [PATCH] silence unused pgdat warning from alloc_bootmem_node and friends
@ 2006-11-22 14:38 Andy Whitcroft
2006-11-22 21:24 ` Andrew Morton
0 siblings, 1 reply; 3+ messages in thread
From: Andy Whitcroft @ 2006-11-22 14:38 UTC (permalink / raw)
To: Andrew Morton; +Cc: linux-kernel, apw
silence unused pgdat warning from alloc_bootmem_node and friends
x86 NUMA systems only define bootmem for node 0. alloc_bootmem_node()
and friends therefore ignore the passed pgdat and use NODE_DATA(0)
in all cases. This leads to the following warnings as we are not
using the passed parameter:
.../mm/page_alloc.c: In function 'zone_wait_table_init':
.../mm/page_alloc.c:2259: warning: unused variable 'pgdat'
One option would be to define all variables used with these macros
__attribute__ ((unused)), but this would leave us exposed should
these become genuinely unused.
The key here is that we _are_ using the value, we ignore it but that
is a deliberate action. This patch adds a nested local variable
within the alloc_bootmem_node helper to which the pgdat parameter is
assigned making it 'used'. The nested local is marked __attribute__
((unused)) to silence this same warning for it.
Against 2.6.19-rc5-mm2.
Signed-off-by: Andy Whitcroft <apw@shadowen.org>
---
diff --git a/include/asm-i386/mmzone.h b/include/asm-i386/mmzone.h
index 61b0733..3503ad6 100644
--- a/include/asm-i386/mmzone.h
+++ b/include/asm-i386/mmzone.h
@@ -120,13 +120,26 @@ static inline int pfn_valid(int pfn)
__alloc_bootmem_node(NODE_DATA(0), (x), PAGE_SIZE, __pa(MAX_DMA_ADDRESS))
#define alloc_bootmem_low_pages(x) \
__alloc_bootmem_node(NODE_DATA(0), (x), PAGE_SIZE, 0)
-#define alloc_bootmem_node(ignore, x) \
- __alloc_bootmem_node(NODE_DATA(0), (x), SMP_CACHE_BYTES, __pa(MAX_DMA_ADDRESS))
-#define alloc_bootmem_pages_node(ignore, x) \
- __alloc_bootmem_node(NODE_DATA(0), (x), PAGE_SIZE, __pa(MAX_DMA_ADDRESS))
-#define alloc_bootmem_low_pages_node(ignore, x) \
- __alloc_bootmem_node(NODE_DATA(0), (x), PAGE_SIZE, 0)
-
+#define alloc_bootmem_node(pgdat, x) \
+({ \
+ struct pglist_data __attribute__ ((unused)) \
+ *__alloc_bootmem_node__pgdat = (pgdat); \
+ __alloc_bootmem_node(NODE_DATA(0), (x), SMP_CACHE_BYTES, \
+ __pa(MAX_DMA_ADDRESS)); \
+})
+#define alloc_bootmem_pages_node(pgdat, x) \
+({ \
+ struct pglist_data __attribute__ ((unused)) \
+ *__alloc_bootmem_node__pgdat = (pgdat); \
+ __alloc_bootmem_node(NODE_DATA(0), (x), PAGE_SIZE, \
+ __pa(MAX_DMA_ADDRESS)) \
+})
+#define alloc_bootmem_low_pages_node(pgdat, x) \
+({ \
+ struct pglist_data __attribute__ ((unused)) \
+ *__alloc_bootmem_node__pgdat = (pgdat); \
+ __alloc_bootmem_node(NODE_DATA(0), (x), PAGE_SIZE, 0); \
+})
#endif /* CONFIG_NEED_MULTIPLE_NODES */
#endif /* _ASM_MMZONE_H_ */
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] silence unused pgdat warning from alloc_bootmem_node and friends
2006-11-22 14:38 [PATCH] silence unused pgdat warning from alloc_bootmem_node and friends Andy Whitcroft
@ 2006-11-22 21:24 ` Andrew Morton
2006-11-23 9:16 ` Andy Whitcroft
0 siblings, 1 reply; 3+ messages in thread
From: Andrew Morton @ 2006-11-22 21:24 UTC (permalink / raw)
To: Andy Whitcroft; +Cc: linux-kernel
On Wed, 22 Nov 2006 14:38:51 +0000
Andy Whitcroft <apw@shadowen.org> wrote:
> silence unused pgdat warning from alloc_bootmem_node and friends
>
> x86 NUMA systems only define bootmem for node 0. alloc_bootmem_node()
> and friends therefore ignore the passed pgdat and use NODE_DATA(0)
> in all cases. This leads to the following warnings as we are not
> using the passed parameter:
>
> .../mm/page_alloc.c: In function 'zone_wait_table_init':
> .../mm/page_alloc.c:2259: warning: unused variable 'pgdat'
>
> One option would be to define all variables used with these macros
> __attribute__ ((unused)), but this would leave us exposed should
> these become genuinely unused.
>
> The key here is that we _are_ using the value, we ignore it but that
> is a deliberate action. This patch adds a nested local variable
> within the alloc_bootmem_node helper to which the pgdat parameter is
> assigned making it 'used'. The nested local is marked __attribute__
> ((unused)) to silence this same warning for it.
>
> Against 2.6.19-rc5-mm2.
>
> Signed-off-by: Andy Whitcroft <apw@shadowen.org>
> ---
> diff --git a/include/asm-i386/mmzone.h b/include/asm-i386/mmzone.h
> index 61b0733..3503ad6 100644
> --- a/include/asm-i386/mmzone.h
> +++ b/include/asm-i386/mmzone.h
> @@ -120,13 +120,26 @@ static inline int pfn_valid(int pfn)
> __alloc_bootmem_node(NODE_DATA(0), (x), PAGE_SIZE, __pa(MAX_DMA_ADDRESS))
> #define alloc_bootmem_low_pages(x) \
> __alloc_bootmem_node(NODE_DATA(0), (x), PAGE_SIZE, 0)
> -#define alloc_bootmem_node(ignore, x) \
> - __alloc_bootmem_node(NODE_DATA(0), (x), SMP_CACHE_BYTES, __pa(MAX_DMA_ADDRESS))
> -#define alloc_bootmem_pages_node(ignore, x) \
> - __alloc_bootmem_node(NODE_DATA(0), (x), PAGE_SIZE, __pa(MAX_DMA_ADDRESS))
> -#define alloc_bootmem_low_pages_node(ignore, x) \
> - __alloc_bootmem_node(NODE_DATA(0), (x), PAGE_SIZE, 0)
> -
> +#define alloc_bootmem_node(pgdat, x) \
> +({ \
> + struct pglist_data __attribute__ ((unused)) \
> + *__alloc_bootmem_node__pgdat = (pgdat); \
> + __alloc_bootmem_node(NODE_DATA(0), (x), SMP_CACHE_BYTES, \
> + __pa(MAX_DMA_ADDRESS)); \
> +})
> +#define alloc_bootmem_pages_node(pgdat, x) \
> +({ \
> + struct pglist_data __attribute__ ((unused)) \
> + *__alloc_bootmem_node__pgdat = (pgdat); \
> + __alloc_bootmem_node(NODE_DATA(0), (x), PAGE_SIZE, \
> + __pa(MAX_DMA_ADDRESS)) \
> +})
> +#define alloc_bootmem_low_pages_node(pgdat, x) \
> +({ \
> + struct pglist_data __attribute__ ((unused)) \
> + *__alloc_bootmem_node__pgdat = (pgdat); \
> + __alloc_bootmem_node(NODE_DATA(0), (x), PAGE_SIZE, 0); \
> +})
> #endif /* CONFIG_NEED_MULTIPLE_NODES */
>
Can these be switched to functions, or do they actually need to be macros?
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] silence unused pgdat warning from alloc_bootmem_node and friends
2006-11-22 21:24 ` Andrew Morton
@ 2006-11-23 9:16 ` Andy Whitcroft
0 siblings, 0 replies; 3+ messages in thread
From: Andy Whitcroft @ 2006-11-23 9:16 UTC (permalink / raw)
To: Andrew Morton; +Cc: linux-kernel
Andrew Morton wrote:
> On Wed, 22 Nov 2006 14:38:51 +0000
> Andy Whitcroft <apw@shadowen.org> wrote:
>
>> silence unused pgdat warning from alloc_bootmem_node and friends
>>
>> x86 NUMA systems only define bootmem for node 0. alloc_bootmem_node()
>> and friends therefore ignore the passed pgdat and use NODE_DATA(0)
>> in all cases. This leads to the following warnings as we are not
>> using the passed parameter:
>>
>> .../mm/page_alloc.c: In function 'zone_wait_table_init':
>> .../mm/page_alloc.c:2259: warning: unused variable 'pgdat'
>>
>> One option would be to define all variables used with these macros
>> __attribute__ ((unused)), but this would leave us exposed should
>> these become genuinely unused.
>>
>> The key here is that we _are_ using the value, we ignore it but that
>> is a deliberate action. This patch adds a nested local variable
>> within the alloc_bootmem_node helper to which the pgdat parameter is
>> assigned making it 'used'. The nested local is marked __attribute__
>> ((unused)) to silence this same warning for it.
>>
>> Against 2.6.19-rc5-mm2.
>>
>> Signed-off-by: Andy Whitcroft <apw@shadowen.org>
>> ---
>> diff --git a/include/asm-i386/mmzone.h b/include/asm-i386/mmzone.h
>> index 61b0733..3503ad6 100644
>> --- a/include/asm-i386/mmzone.h
>> +++ b/include/asm-i386/mmzone.h
>> @@ -120,13 +120,26 @@ static inline int pfn_valid(int pfn)
>> __alloc_bootmem_node(NODE_DATA(0), (x), PAGE_SIZE, __pa(MAX_DMA_ADDRESS))
>> #define alloc_bootmem_low_pages(x) \
>> __alloc_bootmem_node(NODE_DATA(0), (x), PAGE_SIZE, 0)
>> -#define alloc_bootmem_node(ignore, x) \
>> - __alloc_bootmem_node(NODE_DATA(0), (x), SMP_CACHE_BYTES, __pa(MAX_DMA_ADDRESS))
>> -#define alloc_bootmem_pages_node(ignore, x) \
>> - __alloc_bootmem_node(NODE_DATA(0), (x), PAGE_SIZE, __pa(MAX_DMA_ADDRESS))
>> -#define alloc_bootmem_low_pages_node(ignore, x) \
>> - __alloc_bootmem_node(NODE_DATA(0), (x), PAGE_SIZE, 0)
>> -
>> +#define alloc_bootmem_node(pgdat, x) \
>> +({ \
>> + struct pglist_data __attribute__ ((unused)) \
>> + *__alloc_bootmem_node__pgdat = (pgdat); \
>> + __alloc_bootmem_node(NODE_DATA(0), (x), SMP_CACHE_BYTES, \
>> + __pa(MAX_DMA_ADDRESS)); \
>> +})
>> +#define alloc_bootmem_pages_node(pgdat, x) \
>> +({ \
>> + struct pglist_data __attribute__ ((unused)) \
>> + *__alloc_bootmem_node__pgdat = (pgdat); \
>> + __alloc_bootmem_node(NODE_DATA(0), (x), PAGE_SIZE, \
>> + __pa(MAX_DMA_ADDRESS)) \
>> +})
>> +#define alloc_bootmem_low_pages_node(pgdat, x) \
>> +({ \
>> + struct pglist_data __attribute__ ((unused)) \
>> + *__alloc_bootmem_node__pgdat = (pgdat); \
>> + __alloc_bootmem_node(NODE_DATA(0), (x), PAGE_SIZE, 0); \
>> +})
>> #endif /* CONFIG_NEED_MULTIPLE_NODES */
>>
>
> Can these be switched to functions, or do they actually need to be macros?
I did first attempt to make them inline functions, that leads us to some
new dependancies such as on MAX_DMA_ADDRESS. I must admit to backing
off at that point, the dependancy problems between mmzone.h and mm.h
caused huge amounts of problems for me in the past and I was shy of
playng with them again.
I'll take a look see if thats the only one or if it is indeed still
endemic. I know some of the issues were fixed with additional headers.
-apw
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