diff options
| -rw-r--r-- | include/linux/compaction.h | 39 | ||||
| -rw-r--r-- | include/linux/mmzone.h | 9 | ||||
| -rw-r--r-- | mm/page_alloc.c | 5 |
3 files changed, 52 insertions, 1 deletions
diff --git a/include/linux/compaction.h b/include/linux/compaction.h index 3719325..5ac5155 100644 --- a/include/linux/compaction.h +++ b/include/linux/compaction.h @@ -22,6 +22,36 @@ extern int sysctl_extfrag_handler(struct ctl_table *table, int write, extern int fragmentation_index(struct zone *zone, unsigned int order); extern unsigned long try_to_compact_pages(struct zonelist *zonelist, int order, gfp_t gfp_mask, nodemask_t *mask); + +/* Do not skip compaction more than 64 times */ +#define COMPACT_MAX_DEFER_SHIFT 6 + +/* + * Compaction is deferred when compaction fails to result in a page + * allocation success. 1 << compact_defer_limit compactions are skipped up + * to a limit of 1 << COMPACT_MAX_DEFER_SHIFT + */ +static inline void defer_compaction(struct zone *zone) +{ + zone->compact_considered = 0; + zone->compact_defer_shift++; + + if (zone->compact_defer_shift > COMPACT_MAX_DEFER_SHIFT) + zone->compact_defer_shift = COMPACT_MAX_DEFER_SHIFT; +} + +/* Returns true if compaction should be skipped this time */ +static inline bool compaction_deferred(struct zone *zone) +{ + unsigned long defer_limit = 1UL << zone->compact_defer_shift; + + /* Avoid possible overflow */ + if (++zone->compact_considered > defer_limit) + zone->compact_considered = defer_limit; + + return zone->compact_considered < (1UL << zone->compact_defer_shift); +} + #else static inline unsigned long try_to_compact_pages(struct zonelist *zonelist, int order, gfp_t gfp_mask, nodemask_t *nodemask) @@ -29,6 +59,15 @@ static inline unsigned long try_to_compact_pages(struct zonelist *zonelist, return COMPACT_CONTINUE; } +static inline void defer_compaction(struct zone *zone) +{ +} + +static inline bool compaction_deferred(struct zone *zone) +{ + return 1; +} + #endif /* CONFIG_COMPACTION */ #if defined(CONFIG_COMPACTION) && defined(CONFIG_SYSFS) && defined(CONFIG_NUMA) diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index cf9e458..fd55f72 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -321,6 +321,15 @@ struct zone { unsigned long *pageblock_flags; #endif /* CONFIG_SPARSEMEM */ +#ifdef CONFIG_COMPACTION + /* + * On compaction failure, 1<<compact_defer_shift compactions + * are skipped before trying again. The number attempted since + * last failure is tracked with compact_considered. + */ + unsigned int compact_considered; + unsigned int compact_defer_shift; +#endif ZONE_PADDING(_pad1_) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index cd88a86..95ad42d 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1769,7 +1769,7 @@ __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order, { struct page *page; - if (!order) + if (!order || compaction_deferred(preferred_zone)) return NULL; *did_some_progress = try_to_compact_pages(zonelist, order, gfp_mask, @@ -1785,6 +1785,8 @@ __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order, alloc_flags, preferred_zone, migratetype); if (page) { + preferred_zone->compact_considered = 0; + preferred_zone->compact_defer_shift = 0; count_vm_event(COMPACTSUCCESS); return page; } @@ -1795,6 +1797,7 @@ __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order, * but not enough to satisfy watermarks. */ count_vm_event(COMPACTFAIL); + defer_compaction(preferred_zone); cond_resched(); } |
