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? > Ah, good point. I wonder if we can get away with page_count(page) - page_mapcount(page) > 1 to avoid the get_user_pages() pin? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>