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246 lines
7.1 KiB
246 lines
7.1 KiB
/* SPDX-License-Identifier: GPL-2.0 */ |
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#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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/* 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 unsigned int sysctl_compaction_proactiveness; |
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extern int sysctl_compaction_handler(struct ctl_table *table, int write, |
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void *buffer, size_t *length, loff_t *ppos); |
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extern int sysctl_extfrag_threshold; |
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extern int sysctl_compact_unevictable_allowed; |
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extern unsigned int extfrag_for_order(struct zone *zone, unsigned int order); |
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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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struct page **page); |
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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 highest_zoneidx); |
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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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/* 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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/* Compaction needs reclaim to be performed first, so it can continue. */ |
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static inline bool compaction_needs_reclaim(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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return false; |
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} |
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/* |
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* Compaction has backed off for some reason after doing some work or none |
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* at all. It might be throttling or lock contention. Retrying might be still |
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* worthwhile, but with a higher priority if allowed. |
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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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* 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 highest_zoneidx); |
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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 highest_zoneidx) |
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{ |
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return COMPACT_SKIPPED; |
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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_needs_reclaim(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, |
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int order, int highest_zoneidx) |
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{ |
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} |
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#endif /* CONFIG_COMPACTION */ |
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struct node; |
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#if defined(CONFIG_COMPACTION) && defined(CONFIG_SYSFS) && defined(CONFIG_NUMA) |
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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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