Messages in this thread | | | Date | Wed, 30 Oct 2013 21:35:37 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH] mm: __rmqueue_fallback() should respect pageblock type |
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On Thu, 31 Oct 2013 00:24:49 -0400 kosaki.motohiro@gmail.com wrote:
> When __rmqueue_fallback() don't find out a free block with the same size > of required, it splits a larger page and puts back rest peiece of the page > to free list. > > But it has one serious mistake. When putting back, __rmqueue_fallback() > always use start_migratetype if type is not CMA. However, __rmqueue_fallback() > is only called when all of start_migratetype queue are empty. That said, > __rmqueue_fallback always put back memory to wrong queue except > try_to_steal_freepages() changed pageblock type (i.e. requested size is > smaller than half of page block). Finally, antifragmentation framework > increase fragmenation instead of decrease. > > Mel's original anti fragmentation do the right thing. But commit 47118af076 > (mm: mmzone: MIGRATE_CMA migration type added) broke it. > > This patch restores sane and old behavior.
What are the user-visible runtime effects of this change?
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