02aa0cdd72
When stealing pages from pageblock of a different migratetype, we count how many free pages were stolen, and change the pageblock's migratetype if more than half of the pageblock was free. This might be too conservative, as there might be other pages that are not free, but were allocated with the same migratetype as our allocation requested. While we cannot determine the migratetype of allocated pages precisely (at least without the page_owner functionality enabled), we can count pages that compaction would try to isolate for migration - those are either on LRU or __PageMovable(). The rest can be assumed to be MIGRATE_RECLAIMABLE or MIGRATE_UNMOVABLE, which we cannot easily distinguish. This counting can be done as part of free page stealing with little additional overhead. The page stealing code is changed so that it considers free pages plus pages of the "good" migratetype for the decision whether to change pageblock's migratetype. The result should be more accurate migratetype of pageblocks wrt the actual pages in the pageblocks, when stealing from semi-occupied pageblocks. This should help the efficiency of page grouping by mobility. In testing based on 4.9 kernel with stress-highalloc from mmtests configured for order-4 GFP_KERNEL allocations, this patch has reduced the number of unmovable allocations falling back to movable pageblocks by 47%. The number of movable allocations falling back to other pageblocks are increased by 55%, but these events don't cause permanent fragmentation, so the tradeoff should be positive. Later patches also offset the movable fallback increase to some extent. [akpm@linux-foundation.org: merge fix] Link: http://lkml.kernel.org/r/20170307131545.28577-5-vbabka@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Mel Gorman <mgorman@techsingularity.net> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
69 lines
1.8 KiB
C
69 lines
1.8 KiB
C
#ifndef __LINUX_PAGEISOLATION_H
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#define __LINUX_PAGEISOLATION_H
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#ifdef CONFIG_MEMORY_ISOLATION
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static inline bool has_isolate_pageblock(struct zone *zone)
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{
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return zone->nr_isolate_pageblock;
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}
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static inline bool is_migrate_isolate_page(struct page *page)
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{
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return get_pageblock_migratetype(page) == MIGRATE_ISOLATE;
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}
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static inline bool is_migrate_isolate(int migratetype)
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{
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return migratetype == MIGRATE_ISOLATE;
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}
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#else
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static inline bool has_isolate_pageblock(struct zone *zone)
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{
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return false;
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}
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static inline bool is_migrate_isolate_page(struct page *page)
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{
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return false;
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}
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static inline bool is_migrate_isolate(int migratetype)
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{
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return false;
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}
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#endif
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bool has_unmovable_pages(struct zone *zone, struct page *page, int count,
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bool skip_hwpoisoned_pages);
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void set_pageblock_migratetype(struct page *page, int migratetype);
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int move_freepages_block(struct zone *zone, struct page *page,
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int migratetype, int *num_movable);
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/*
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* Changes migrate type in [start_pfn, end_pfn) to be MIGRATE_ISOLATE.
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* If specified range includes migrate types other than MOVABLE or CMA,
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* this will fail with -EBUSY.
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*
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* For isolating all pages in the range finally, the caller have to
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* free all pages in the range. test_page_isolated() can be used for
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* test it.
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*/
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int
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start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
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unsigned migratetype, bool skip_hwpoisoned_pages);
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/*
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* Changes MIGRATE_ISOLATE to MIGRATE_MOVABLE.
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* target range is [start_pfn, end_pfn)
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*/
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int
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undo_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
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unsigned migratetype);
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/*
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* Test all pages in [start_pfn, end_pfn) are isolated or not.
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*/
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int test_pages_isolated(unsigned long start_pfn, unsigned long end_pfn,
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bool skip_hwpoisoned_pages);
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struct page *alloc_migrate_target(struct page *page, unsigned long private,
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int **resultp);
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#endif
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