Line data    Source code

       1             : /* SPDX-License-Identifier: GPL-2.0 */
       2             : #ifndef _LINUX_COMPACTION_H
       3             : #define _LINUX_COMPACTION_H
       4             : 
       5             : /*
       6             :  * Determines how hard direct compaction should try to succeed.
       7             :  * Lower value means higher priority, analogically to reclaim priority.
       8             :  */
       9             : enum compact_priority {
      10             :         COMPACT_PRIO_SYNC_FULL,
      11             :         MIN_COMPACT_PRIORITY = COMPACT_PRIO_SYNC_FULL,
      12             :         COMPACT_PRIO_SYNC_LIGHT,
      13             :         MIN_COMPACT_COSTLY_PRIORITY = COMPACT_PRIO_SYNC_LIGHT,
      14             :         DEF_COMPACT_PRIORITY = COMPACT_PRIO_SYNC_LIGHT,
      15             :         COMPACT_PRIO_ASYNC,
      16             :         INIT_COMPACT_PRIORITY = COMPACT_PRIO_ASYNC
      17             : };
      18             : 
      19             : /* Return values for compact_zone() and try_to_compact_pages() */
      20             : /* When adding new states, please adjust include/trace/events/compaction.h */
      21             : enum compact_result {
      22             :         /* For more detailed tracepoint output - internal to compaction */
      23             :         COMPACT_NOT_SUITABLE_ZONE,
      24             :         /*
      25             :          * compaction didn't start as it was not possible or direct reclaim
      26             :          * was more suitable
      27             :          */
      28             :         COMPACT_SKIPPED,
      29             :         /* compaction didn't start as it was deferred due to past failures */
      30             :         COMPACT_DEFERRED,
      31             : 
      32             :         /* For more detailed tracepoint output - internal to compaction */
      33             :         COMPACT_NO_SUITABLE_PAGE,
      34             :         /* compaction should continue to another pageblock */
      35             :         COMPACT_CONTINUE,
      36             : 
      37             :         /*
      38             :          * The full zone was compacted scanned but wasn't successful to compact
      39             :          * suitable pages.
      40             :          */
      41             :         COMPACT_COMPLETE,
      42             :         /*
      43             :          * direct compaction has scanned part of the zone but wasn't successful
      44             :          * to compact suitable pages.
      45             :          */
      46             :         COMPACT_PARTIAL_SKIPPED,
      47             : 
      48             :         /* compaction terminated prematurely due to lock contentions */
      49             :         COMPACT_CONTENDED,
      50             : 
      51             :         /*
      52             :          * direct compaction terminated after concluding that the allocation
      53             :          * should now succeed
      54             :          */
      55             :         COMPACT_SUCCESS,
      56             : };
      57             : 
      58             : struct alloc_context; /* in mm/internal.h */
      59             : 
      60             : /*
      61             :  * Number of free order-0 pages that should be available above given watermark
      62             :  * to make sure compaction has reasonable chance of not running out of free
      63             :  * pages that it needs to isolate as migration target during its work.
      64             :  */
      65             : static inline unsigned long compact_gap(unsigned int order)
      66             : {
      67             :         /*
      68             :          * Although all the isolations for migration are temporary, compaction
      69             :          * free scanner may have up to 1 << order pages on its list and then
      70             :          * try to split an (order - 1) free page. At that point, a gap of
      71             :          * 1 << order might not be enough, so it's safer to require twice that
      72             :          * amount. Note that the number of pages on the list is also
      73             :          * effectively limited by COMPACT_CLUSTER_MAX, as that's the maximum
      74             :          * that the migrate scanner can have isolated on migrate list, and free
      75             :          * scanner is only invoked when the number of isolated free pages is
      76             :          * lower than that. But it's not worth to complicate the formula here
      77             :          * as a bigger gap for higher orders than strictly necessary can also
      78             :          * improve chances of compaction success.
      79             :          */
      80           0 :         return 2UL << order;
      81             : }
      82             : 
      83             : #ifdef CONFIG_COMPACTION
      84             : 
      85             : extern unsigned int extfrag_for_order(struct zone *zone, unsigned int order);
      86             : extern int fragmentation_index(struct zone *zone, unsigned int order);
      87             : extern enum compact_result try_to_compact_pages(gfp_t gfp_mask,
      88             :                 unsigned int order, unsigned int alloc_flags,
      89             :                 const struct alloc_context *ac, enum compact_priority prio,
      90             :                 struct page **page);
      91             : extern void reset_isolation_suitable(pg_data_t *pgdat);
      92             : extern bool compaction_suitable(struct zone *zone, int order,
      93             :                                                int highest_zoneidx);
      94             : 
      95             : extern void compaction_defer_reset(struct zone *zone, int order,
      96             :                                 bool alloc_success);
      97             : 
      98             : bool compaction_zonelist_suitable(struct alloc_context *ac, int order,
      99             :                                         int alloc_flags);
     100             : 
     101             : extern void __meminit kcompactd_run(int nid);
     102             : extern void __meminit kcompactd_stop(int nid);
     103             : extern void wakeup_kcompactd(pg_data_t *pgdat, int order, int highest_zoneidx);
     104             : 
     105             : #else
     106             : static inline void reset_isolation_suitable(pg_data_t *pgdat)
     107             : {
     108             : }
     109             : 
     110             : static inline bool compaction_suitable(struct zone *zone, int order,
     111             :                                                       int highest_zoneidx)
     112             : {
     113             :         return false;
     114             : }
     115             : 
     116             : static inline void kcompactd_run(int nid)
     117             : {
     118             : }
     119             : static inline void kcompactd_stop(int nid)
     120             : {
     121             : }
     122             : 
     123             : static inline void wakeup_kcompactd(pg_data_t *pgdat,
     124             :                                 int order, int highest_zoneidx)
     125             : {
     126             : }
     127             : 
     128             : #endif /* CONFIG_COMPACTION */
     129             : 
     130             : struct node;
     131             : #if defined(CONFIG_COMPACTION) && defined(CONFIG_SYSFS) && defined(CONFIG_NUMA)
     132             : extern int compaction_register_node(struct node *node);
     133             : extern void compaction_unregister_node(struct node *node);
     134             : 
     135             : #else
     136             : 
     137             : static inline int compaction_register_node(struct node *node)
     138             : {
     139             :         return 0;
     140             : }
     141             : 
     142             : static inline void compaction_unregister_node(struct node *node)
     143             : {
     144             : }
     145             : #endif /* CONFIG_COMPACTION && CONFIG_SYSFS && CONFIG_NUMA */
     146             : 
     147             : #endif /* _LINUX_COMPACTION_H */