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* [PATCH mmotm] mm: use unsigned int for page order fix 2
@ 2015-10-16 22:51 Hugh Dickins
  2015-10-16 23:00 ` Andrew Morton
  0 siblings, 1 reply; 3+ messages in thread
From: Hugh Dickins @ 2015-10-16 22:51 UTC (permalink / raw)
  To: Andrew Morton
  Cc: Kirill A. Shutemov, Stephen Rothwell, linux-kernel, linux-mm

Some configs now end up with MAX_ORDER and pageblock_order having
different types: silence compiler warning in __free_one_page().

Signed-off-by: Hugh Dickins <hughd@google.com>

--- mmotm/mm/page_alloc.c	2015-10-15 15:26:59.855572338 -0700
+++ linux/mm/page_alloc.c	2015-10-16 11:54:20.847027790 -0700
@@ -679,7 +679,7 @@ static inline void __free_one_page(struc
 		 * pageblock. Without this, pageblock isolation
 		 * could cause incorrect freepage accounting.
 		 */
-		max_order = min(MAX_ORDER, pageblock_order + 1);
+		max_order = min_t(unsigned int, MAX_ORDER, pageblock_order + 1);
 	} else {
 		__mod_zone_freepage_state(zone, 1 << order, migratetype);
 	}

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^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH mmotm] mm: use unsigned int for page order fix 2
  2015-10-16 22:51 [PATCH mmotm] mm: use unsigned int for page order fix 2 Hugh Dickins
@ 2015-10-16 23:00 ` Andrew Morton
  2015-10-16 23:07   ` Hugh Dickins
  0 siblings, 1 reply; 3+ messages in thread
From: Andrew Morton @ 2015-10-16 23:00 UTC (permalink / raw)
  To: Hugh Dickins; +Cc: Kirill A. Shutemov, Stephen Rothwell, linux-kernel, linux-mm

On Fri, 16 Oct 2015 15:51:34 -0700 (PDT) Hugh Dickins <hughd@google.com> wrote:

> Some configs now end up with MAX_ORDER and pageblock_order having
> different types: silence compiler warning in __free_one_page().
> 
> ...
>
> @@ -679,7 +679,7 @@ static inline void __free_one_page(struc
>  		 * pageblock. Without this, pageblock isolation
>  		 * could cause incorrect freepage accounting.
>  		 */
> -		max_order = min(MAX_ORDER, pageblock_order + 1);
> +		max_order = min_t(unsigned int, MAX_ORDER, pageblock_order + 1);
>  	} else {
>  		__mod_zone_freepage_state(zone, 1 << order, migratetype);
>  	}

Well.  If we're ordaining that "page order has type uint" then can we
do that more consistently?  Something like

--- a/include/linux/mmzone.h~a
+++ a/include/linux/mmzone.h
@@ -21,9 +21,9 @@
 
 /* Free memory management - zoned buddy allocator.  */
 #ifndef CONFIG_FORCE_MAX_ZONEORDER
-#define MAX_ORDER 11
+#define MAX_ORDER 11U
 #else
-#define MAX_ORDER CONFIG_FORCE_MAX_ZONEORDER
+#define MAX_ORDER ((unsigned int)CONFIG_FORCE_MAX_ZONEORDER)
 #endif
 #define MAX_ORDER_NR_PAGES (1 << (MAX_ORDER - 1))
 
diff -puN include/linux/pageblock-flags.h~a include/linux/pageblock-flags.h
--- a/include/linux/pageblock-flags.h~a
+++ a/include/linux/pageblock-flags.h
@@ -49,7 +49,7 @@ extern unsigned int pageblock_order;
 #else /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
 
 /* Huge pages are a constant size */
-#define pageblock_order		HUGETLB_PAGE_ORDER
+#define pageblock_order		((unsigned int)HUGETLB_PAGE_ORDER)
 
 #endif /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
 
_

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^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH mmotm] mm: use unsigned int for page order fix 2
  2015-10-16 23:00 ` Andrew Morton
@ 2015-10-16 23:07   ` Hugh Dickins
  0 siblings, 0 replies; 3+ messages in thread
From: Hugh Dickins @ 2015-10-16 23:07 UTC (permalink / raw)
  To: Andrew Morton
  Cc: Hugh Dickins, Kirill A. Shutemov, Stephen Rothwell, linux-kernel,
	linux-mm

On Fri, 16 Oct 2015, Andrew Morton wrote:
> On Fri, 16 Oct 2015 15:51:34 -0700 (PDT) Hugh Dickins <hughd@google.com> wrote:
> 
> > Some configs now end up with MAX_ORDER and pageblock_order having
> > different types: silence compiler warning in __free_one_page().
> > 
> > ...
> >
> > @@ -679,7 +679,7 @@ static inline void __free_one_page(struc
> >  		 * pageblock. Without this, pageblock isolation
> >  		 * could cause incorrect freepage accounting.
> >  		 */
> > -		max_order = min(MAX_ORDER, pageblock_order + 1);
> > +		max_order = min_t(unsigned int, MAX_ORDER, pageblock_order + 1);
> >  	} else {
> >  		__mod_zone_freepage_state(zone, 1 << order, migratetype);
> >  	}
> 
> Well.  If we're ordaining that "page order has type uint" then can we
> do that more consistently?  Something like

Yes, if we are going this way, then it is better to be thorough than
patch around it as I did.  (But personally I think the exercise is a
waste of time, so I just took the quickest way out, sorry.)

Hugh

> 
> --- a/include/linux/mmzone.h~a
> +++ a/include/linux/mmzone.h
> @@ -21,9 +21,9 @@
>  
>  /* Free memory management - zoned buddy allocator.  */
>  #ifndef CONFIG_FORCE_MAX_ZONEORDER
> -#define MAX_ORDER 11
> +#define MAX_ORDER 11U
>  #else
> -#define MAX_ORDER CONFIG_FORCE_MAX_ZONEORDER
> +#define MAX_ORDER ((unsigned int)CONFIG_FORCE_MAX_ZONEORDER)
>  #endif
>  #define MAX_ORDER_NR_PAGES (1 << (MAX_ORDER - 1))
>  
> diff -puN include/linux/pageblock-flags.h~a include/linux/pageblock-flags.h
> --- a/include/linux/pageblock-flags.h~a
> +++ a/include/linux/pageblock-flags.h
> @@ -49,7 +49,7 @@ extern unsigned int pageblock_order;
>  #else /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
>  
>  /* Huge pages are a constant size */
> -#define pageblock_order		HUGETLB_PAGE_ORDER
> +#define pageblock_order		((unsigned int)HUGETLB_PAGE_ORDER)
>  
>  #endif /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
>  
> _

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^ permalink raw reply	[flat|nested] 3+ messages in thread

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2015-10-16 22:51 [PATCH mmotm] mm: use unsigned int for page order fix 2 Hugh Dickins
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