forked from rrcarlosr/Jetpack
247 lines
7.1 KiB
C
247 lines
7.1 KiB
C
#ifndef _LINUX_COMPACTION_H
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#define _LINUX_COMPACTION_H
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/*
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* Determines how hard direct compaction should try to succeed.
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* Lower value means higher priority, analogically to reclaim priority.
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*/
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enum compact_priority {
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COMPACT_PRIO_SYNC_FULL,
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MIN_COMPACT_PRIORITY = COMPACT_PRIO_SYNC_FULL,
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COMPACT_PRIO_SYNC_LIGHT,
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MIN_COMPACT_COSTLY_PRIORITY = COMPACT_PRIO_SYNC_LIGHT,
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DEF_COMPACT_PRIORITY = COMPACT_PRIO_SYNC_LIGHT,
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COMPACT_PRIO_ASYNC,
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INIT_COMPACT_PRIORITY = COMPACT_PRIO_ASYNC
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};
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/* Return values for compact_zone() and try_to_compact_pages() */
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/* When adding new states, please adjust include/trace/events/compaction.h */
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enum compact_result {
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/* For more detailed tracepoint output - internal to compaction */
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COMPACT_NOT_SUITABLE_ZONE,
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/*
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* compaction didn't start as it was not possible or direct reclaim
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* was more suitable
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*/
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COMPACT_SKIPPED,
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/* compaction didn't start as it was deferred due to past failures */
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COMPACT_DEFERRED,
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/* compaction not active last round */
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COMPACT_INACTIVE = COMPACT_DEFERRED,
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/* For more detailed tracepoint output - internal to compaction */
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COMPACT_NO_SUITABLE_PAGE,
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/* compaction should continue to another pageblock */
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COMPACT_CONTINUE,
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/*
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* The full zone was compacted scanned but wasn't successfull to compact
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* suitable pages.
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*/
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COMPACT_COMPLETE,
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/*
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* direct compaction has scanned part of the zone but wasn't successfull
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* to compact suitable pages.
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*/
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COMPACT_PARTIAL_SKIPPED,
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/* compaction terminated prematurely due to lock contentions */
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COMPACT_CONTENDED,
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/*
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* direct compaction terminated after concluding that the allocation
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* should now succeed
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*/
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COMPACT_SUCCESS,
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};
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struct alloc_context; /* in mm/internal.h */
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/*
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* Number of free order-0 pages that should be available above given watermark
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* to make sure compaction has reasonable chance of not running out of free
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* pages that it needs to isolate as migration target during its work.
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*/
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static inline unsigned long compact_gap(unsigned int order)
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{
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/*
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* Although all the isolations for migration are temporary, compaction
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* free scanner may have up to 1 << order pages on its list and then
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* try to split an (order - 1) free page. At that point, a gap of
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* 1 << order might not be enough, so it's safer to require twice that
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* amount. Note that the number of pages on the list is also
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* effectively limited by COMPACT_CLUSTER_MAX, as that's the maximum
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* that the migrate scanner can have isolated on migrate list, and free
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* scanner is only invoked when the number of isolated free pages is
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* lower than that. But it's not worth to complicate the formula here
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* as a bigger gap for higher orders than strictly necessary can also
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* improve chances of compaction success.
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*/
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return 2UL << order;
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}
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#ifdef CONFIG_COMPACTION
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extern int sysctl_compact_memory;
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extern int sysctl_compaction_handler(struct ctl_table *table, int write,
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void __user *buffer, size_t *length, loff_t *ppos);
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extern int sysctl_extfrag_threshold;
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extern int sysctl_extfrag_handler(struct ctl_table *table, int write,
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void __user *buffer, size_t *length, loff_t *ppos);
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extern int sysctl_compact_unevictable_allowed;
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extern int fragmentation_index(struct zone *zone, unsigned int order);
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extern enum compact_result try_to_compact_pages(gfp_t gfp_mask,
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unsigned int order, unsigned int alloc_flags,
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const struct alloc_context *ac, enum compact_priority prio);
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extern void reset_isolation_suitable(pg_data_t *pgdat);
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extern enum compact_result compaction_suitable(struct zone *zone, int order,
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unsigned int alloc_flags, int classzone_idx);
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extern void defer_compaction(struct zone *zone, int order);
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extern bool compaction_deferred(struct zone *zone, int order);
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extern void compaction_defer_reset(struct zone *zone, int order,
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bool alloc_success);
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extern bool compaction_restarting(struct zone *zone, int order);
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/* Compaction has made some progress and retrying makes sense */
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static inline bool compaction_made_progress(enum compact_result result)
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{
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/*
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* Even though this might sound confusing this in fact tells us
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* that the compaction successfully isolated and migrated some
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* pageblocks.
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*/
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if (result == COMPACT_SUCCESS)
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return true;
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return false;
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}
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/* Compaction has failed and it doesn't make much sense to keep retrying. */
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static inline bool compaction_failed(enum compact_result result)
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{
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/* All zones were scanned completely and still not result. */
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if (result == COMPACT_COMPLETE)
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return true;
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return false;
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}
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/*
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* Compaction has backed off for some reason. It might be throttling or
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* lock contention. Retrying is still worthwhile.
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*/
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static inline bool compaction_withdrawn(enum compact_result result)
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{
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/*
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* Compaction backed off due to watermark checks for order-0
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* so the regular reclaim has to try harder and reclaim something.
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*/
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if (result == COMPACT_SKIPPED)
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return true;
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/*
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* If compaction is deferred for high-order allocations, it is
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* because sync compaction recently failed. If this is the case
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* and the caller requested a THP allocation, we do not want
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* to heavily disrupt the system, so we fail the allocation
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* instead of entering direct reclaim.
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*/
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if (result == COMPACT_DEFERRED)
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return true;
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/*
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* If compaction in async mode encounters contention or blocks higher
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* priority task we back off early rather than cause stalls.
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*/
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if (result == COMPACT_CONTENDED)
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return true;
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/*
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* Page scanners have met but we haven't scanned full zones so this
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* is a back off in fact.
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*/
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if (result == COMPACT_PARTIAL_SKIPPED)
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return true;
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return false;
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}
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bool compaction_zonelist_suitable(struct alloc_context *ac, int order,
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int alloc_flags);
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extern int kcompactd_run(int nid);
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extern void kcompactd_stop(int nid);
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extern void wakeup_kcompactd(pg_data_t *pgdat, int order, int classzone_idx);
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#else
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static inline void reset_isolation_suitable(pg_data_t *pgdat)
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{
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}
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static inline enum compact_result compaction_suitable(struct zone *zone, int order,
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int alloc_flags, int classzone_idx)
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{
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return COMPACT_SKIPPED;
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}
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static inline void defer_compaction(struct zone *zone, int order)
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{
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}
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static inline bool compaction_deferred(struct zone *zone, int order)
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{
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return true;
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}
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static inline bool compaction_made_progress(enum compact_result result)
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{
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return false;
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}
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static inline bool compaction_failed(enum compact_result result)
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{
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return false;
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}
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static inline bool compaction_withdrawn(enum compact_result result)
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{
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return true;
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}
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static inline int kcompactd_run(int nid)
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{
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return 0;
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}
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static inline void kcompactd_stop(int nid)
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{
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}
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static inline void wakeup_kcompactd(pg_data_t *pgdat, int order, int classzone_idx)
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{
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}
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#endif /* CONFIG_COMPACTION */
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#if defined(CONFIG_COMPACTION) && defined(CONFIG_SYSFS) && defined(CONFIG_NUMA)
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struct node;
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extern int compaction_register_node(struct node *node);
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extern void compaction_unregister_node(struct node *node);
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#else
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static inline int compaction_register_node(struct node *node)
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{
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return 0;
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}
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static inline void compaction_unregister_node(struct node *node)
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{
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}
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#endif /* CONFIG_COMPACTION && CONFIG_SYSFS && CONFIG_NUMA */
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#endif /* _LINUX_COMPACTION_H */
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