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* re: mm: page_alloc: calculate classzone_idx once from the zonelist ref
@ 2014-05-20 11:17 Dan Carpenter
  2014-05-20 12:43 ` [PATCH] mm: page_alloc: Calculate " Mel Gorman
  0 siblings, 1 reply; 3+ messages in thread
From: Dan Carpenter @ 2014-05-20 11:17 UTC (permalink / raw)
  To: mgorman; +Cc: linux-mm

Hello Mel Gorman,

The patch a486e00b8283: "mm: page_alloc: calculate classzone_idx once
from the zonelist ref" from May 17, 2014, leads to the following
static checker warning:

	mm/page_alloc.c:2543 __alloc_pages_slowpath()
	warn: we tested 'nodemask' before and it was 'false'

mm/page_alloc.c
  2537           * Find the true preferred zone if the allocation is unconstrained by
  2538           * cpusets.
  2539           */
  2540          if (!(alloc_flags & ALLOC_CPUSET) && !nodemask) {
                                                     ^^^^^^^^^
Patch introduces this test.

  2541                  struct zoneref *preferred_zoneref;
  2542                  preferred_zoneref = first_zones_zonelist(zonelist, high_zoneidx,
  2543                                  nodemask ? : &cpuset_current_mems_allowed,
                                        ^^^^^^^^
Patch introduces this test as well.

  2544                                  &preferred_zone);
  2545                  classzone_idx = zonelist_zone_idx(preferred_zoneref);
  2546          }

regards,
dan carpenter

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

* [PATCH] mm: page_alloc: Calculate classzone_idx once from the zonelist ref
  2014-05-20 11:17 mm: page_alloc: calculate classzone_idx once from the zonelist ref Dan Carpenter
@ 2014-05-20 12:43 ` Mel Gorman
  2014-05-21  0:06   ` David Rientjes
  0 siblings, 1 reply; 3+ messages in thread
From: Mel Gorman @ 2014-05-20 12:43 UTC (permalink / raw)
  To: Andrew Morton; +Cc: linux-mm, Dan Carpenter

Dan Carpenter reported the following bug

	The patch a486e00b8283: "mm: page_alloc: calculate classzone_idx
	once from the zonelist ref" from May 17, 2014, leads to the
	following static checker warning:

        mm/page_alloc.c:2543 __alloc_pages_slowpath()
        warn: we tested 'nodemask' before and it was 'false'

mm/page_alloc.c
  2537           * Find the true preferred zone if the allocation is unconstrained by
  2538           * cpusets.
  2539           */
  2540          if (!(alloc_flags & ALLOC_CPUSET) && !nodemask) {
                                                     ^^^^^^^^^
Patch introduces this test.

  2541                  struct zoneref *preferred_zoneref;
  2542                  preferred_zoneref = first_zones_zonelist(zonelist, high_zoneidx,
  2543                                  nodemask ? : &cpuset_current_mems_allowed,
                                        ^^^^^^^^
Patch introduces this test as well.

  2544                                  &preferred_zone);
  2545                  classzone_idx = zonelist_zone_idx(preferred_zoneref);
  2546          }

This patch should resolve it and is a fix to the mmotm patch
mm-page_alloc-calculate-classzone_idx-once-from-the-zonelist-ref

Signed-off-by: Mel Gorman <mgorman@suse.de>
---
 mm/page_alloc.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 0959b09..ebb947d 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2590,8 +2590,7 @@ restart:
 	if (!(alloc_flags & ALLOC_CPUSET) && !nodemask) {
 		struct zoneref *preferred_zoneref;
 		preferred_zoneref = first_zones_zonelist(zonelist, high_zoneidx,
-				nodemask ? : &cpuset_current_mems_allowed,
-				&preferred_zone);
+				NULL, &preferred_zone);
 		classzone_idx = zonelist_zone_idx(preferred_zoneref);
 	}
 

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

* Re: [PATCH] mm: page_alloc: Calculate classzone_idx once from the zonelist ref
  2014-05-20 12:43 ` [PATCH] mm: page_alloc: Calculate " Mel Gorman
@ 2014-05-21  0:06   ` David Rientjes
  0 siblings, 0 replies; 3+ messages in thread
From: David Rientjes @ 2014-05-21  0:06 UTC (permalink / raw)
  To: Mel Gorman; +Cc: Andrew Morton, linux-mm, Dan Carpenter

On Tue, 20 May 2014, Mel Gorman wrote:

> Dan Carpenter reported the following bug
> 
> 	The patch a486e00b8283: "mm: page_alloc: calculate classzone_idx
> 	once from the zonelist ref" from May 17, 2014, leads to the
> 	following static checker warning:
> 
>         mm/page_alloc.c:2543 __alloc_pages_slowpath()
>         warn: we tested 'nodemask' before and it was 'false'
> 
> mm/page_alloc.c
>   2537           * Find the true preferred zone if the allocation is unconstrained by
>   2538           * cpusets.
>   2539           */
>   2540          if (!(alloc_flags & ALLOC_CPUSET) && !nodemask) {
>                                                      ^^^^^^^^^
> Patch introduces this test.
> 
>   2541                  struct zoneref *preferred_zoneref;
>   2542                  preferred_zoneref = first_zones_zonelist(zonelist, high_zoneidx,
>   2543                                  nodemask ? : &cpuset_current_mems_allowed,
>                                         ^^^^^^^^
> Patch introduces this test as well.
> 
>   2544                                  &preferred_zone);
>   2545                  classzone_idx = zonelist_zone_idx(preferred_zoneref);
>   2546          }
> 
> This patch should resolve it and is a fix to the mmotm patch
> mm-page_alloc-calculate-classzone_idx-once-from-the-zonelist-ref
> 
> Signed-off-by: Mel Gorman <mgorman@suse.de>
> ---
>  mm/page_alloc.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 0959b09..ebb947d 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -2590,8 +2590,7 @@ restart:
>  	if (!(alloc_flags & ALLOC_CPUSET) && !nodemask) {
>  		struct zoneref *preferred_zoneref;
>  		preferred_zoneref = first_zones_zonelist(zonelist, high_zoneidx,
> -				nodemask ? : &cpuset_current_mems_allowed,
> -				&preferred_zone);
> +				NULL, &preferred_zone);
>  		classzone_idx = zonelist_zone_idx(preferred_zoneref);
>  	}
>  

The switch from "nodemask : &cpuset_current_mems_allowed" to NULL isn't 
described in the changelog but makes sense as well because of
!(alloc_flags & ALLOC_CPUSET).

Acked-by: David Rientjes <rientjes@google.com>

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

end of thread, other threads:[~2014-05-21  0:06 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
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2014-05-20 11:17 mm: page_alloc: calculate classzone_idx once from the zonelist ref Dan Carpenter
2014-05-20 12:43 ` [PATCH] mm: page_alloc: Calculate " Mel Gorman
2014-05-21  0:06   ` David Rientjes

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