Messages in this thread | | | Date | Tue, 4 Feb 2014 11:15:33 +0900 | From | Joonsoo Kim <> | Subject | Re: [patch] mm, compaction: avoid isolating pinned pages fix |
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On Mon, Feb 03, 2014 at 06:00:56PM -0800, David Rientjes wrote: > On Tue, 4 Feb 2014, Joonsoo Kim wrote: > > > Okay. It can't fix your situation. Anyway, *normal* anon pages may be mapped > > and have positive page_count(), so your code such as > > '!page_mapping(page) && page_count(page)' makes compaction skip these *normal* > > anon pages and this is incorrect behaviour. > > > > So how does that work with migrate_page_move_mapping() which demands > page_count(page) == 1 and the get_page_unless_zero() in > __isolate_lru_page()?
Before doing migrate_page_move_mapping(), try_to_unmap() is called so that all mapping is unmapped. Then, remained page_count() is 1 which is grabbed by __isolate_lru_page(). Am I missing something?
Thanks.
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