[v2] mm: skip less than check for MAX_NR_ZONES

[PATCH v2] mm: skip less than check for MAX_NR_ZONES

Posted by alexs@kernel.org 1 year, 5 months ago

From: Alex Shi <alexs@kernel.org>

Remove unnecessary '<' check for ZONES_SHIFT assignment.

Signed-off-by: Alex Shi <alexs@kernel.org>
Cc: linux-mm@kvack.org
Cc: Andrew Morton <akpm@linux-foundation.org>
---
 include/linux/page-flags-layout.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/page-flags-layout.h b/include/linux/page-flags-layout.h
index 7d79818dc065..7edc2b8a3414 100644
--- a/include/linux/page-flags-layout.h
+++ b/include/linux/page-flags-layout.h
@@ -14,7 +14,7 @@
  */
 #if MAX_NR_ZONES < 2
 #define ZONES_SHIFT 0
-#elif MAX_NR_ZONES <= 2
+#elif MAX_NR_ZONES == 2
 #define ZONES_SHIFT 1
 #elif MAX_NR_ZONES <= 4
 #define ZONES_SHIFT 2
-- 
2.43.0

Re: [PATCH v2] mm: skip less than check for MAX_NR_ZONES

Posted by Andrew Morton 1 year, 5 months ago

On Mon, 19 Aug 2024 19:26:28 +0800 alexs@kernel.org wrote:

> From: Alex Shi <alexs@kernel.org>
> 
> Remove unnecessary '<' check for ZONES_SHIFT assignment.
> 
> ...
>
> --- a/include/linux/page-flags-layout.h
> +++ b/include/linux/page-flags-layout.h
> @@ -14,7 +14,7 @@
>   */
>  #if MAX_NR_ZONES < 2
>  #define ZONES_SHIFT 0
> -#elif MAX_NR_ZONES <= 2
> +#elif MAX_NR_ZONES == 2
>  #define ZONES_SHIFT 1
>  #elif MAX_NR_ZONES <= 4
>  #define ZONES_SHIFT 2

mmm, why.  I think it looks more logical (and certainly more
consistent) the way things are now.

Re: [PATCH v2] mm: skip less than check for MAX_NR_ZONES

Posted by Alex Shi 1 year, 5 months ago


On 8/20/24 12:40 PM, Andrew Morton wrote:
> On Mon, 19 Aug 2024 19:26:28 +0800 alexs@kernel.org wrote:
> 
>> From: Alex Shi <alexs@kernel.org>
>>
>> Remove unnecessary '<' check for ZONES_SHIFT assignment.
>>
>> ...
>>
>> --- a/include/linux/page-flags-layout.h
>> +++ b/include/linux/page-flags-layout.h
>> @@ -14,7 +14,7 @@
>>   */
>>  #if MAX_NR_ZONES < 2
>>  #define ZONES_SHIFT 0
>> -#elif MAX_NR_ZONES <= 2
>> +#elif MAX_NR_ZONES == 2
>>  #define ZONES_SHIFT 1
>>  #elif MAX_NR_ZONES <= 4
>>  #define ZONES_SHIFT 2
> 
> mmm, why.  I think it looks more logical (and certainly more
> consistent) the way things are now.
> 

Uh, then let's keep the current code if the logical looks better.

In fact, the logical is in preprocess, has nothing change in the final object file.

Thanks for comments!