lkml.org 
[lkml]   [2012]   [Nov]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] mm: compaction: Fix return value of capture_free_page
On 11/26/2012 03:23 AM, Mel Gorman wrote:
> On Wed, Nov 21, 2012 at 02:21:51PM -0500, Dave Hansen wrote:
>>
>> This needs to make it in before 3.7 is released.
>>
>
> This is also required. Dave, can you double check? The surprise is that
> this does not blow up very obviously.
...
> @@ -1422,7 +1422,7 @@ int capture_free_page(struct page *page, int alloc_order, int migratetype)
> }
> }
>
> - return 1UL << order;
> + return 1UL << alloc_order;
> }

compact_capture_page() only looks at the boolean return value out of
capture_free_page(), so it wouldn't notice. split_free_page() does.
But, when it calls capture_free_page(), order==alloc_order, so it
wouldn't make a difference. So, there's probably no actual bug here,
but it's certainly a wrong return value.

We should probably also fix the set_pageblock_migratetype() loop in
there while we're at it. I think it's potentially trampling on the
migration type of pages currently in the allocator. I _think_ that
completes the list of things that need to get audited in there.



\
 
 \ /
  Last update: 2012-11-26 16:21    [W:0.356 / U:0.036 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site