diff options
| -rw-r--r-- | include/linux/compaction.h | 15 | ||||
| -rw-r--r-- | include/linux/mmzone.h | 3 | ||||
| -rw-r--r-- | mm/compaction.c | 50 | ||||
| -rw-r--r-- | mm/page_alloc.c | 1 | ||||
| -rw-r--r-- | mm/vmscan.c | 8 |
5 files changed, 60 insertions, 17 deletions
diff --git a/include/linux/compaction.h b/include/linux/compaction.h index 0e38a1d..6ecb6dc 100644 --- a/include/linux/compaction.h +++ b/include/linux/compaction.h @@ -24,6 +24,7 @@ extern unsigned long try_to_compact_pages(struct zonelist *zonelist, int order, gfp_t gfp_mask, nodemask_t *mask, bool sync, bool *contended, struct page **page); extern int compact_pgdat(pg_data_t *pgdat, int order); +extern void reset_isolation_suitable(pg_data_t *pgdat); extern unsigned long compaction_suitable(struct zone *zone, int order); /* Do not skip compaction more than 64 times */ @@ -61,6 +62,16 @@ static inline bool compaction_deferred(struct zone *zone, int order) return zone->compact_considered < defer_limit; } +/* Returns true if restarting compaction after many failures */ +static inline bool compaction_restarting(struct zone *zone, int order) +{ + if (order < zone->compact_order_failed) + return false; + + return zone->compact_defer_shift == COMPACT_MAX_DEFER_SHIFT && + 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, @@ -74,6 +85,10 @@ static inline int compact_pgdat(pg_data_t *pgdat, int order) return COMPACT_CONTINUE; } +static inline void reset_isolation_suitable(pg_data_t *pgdat) +{ +} + static inline unsigned long compaction_suitable(struct zone *zone, int order) { return COMPACT_SKIPPED; diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index c8b3abc..d240efa 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -370,7 +370,8 @@ struct zone { spinlock_t lock; int all_unreclaimable; /* All pages pinned */ #if defined CONFIG_COMPACTION || defined CONFIG_CMA - unsigned long compact_blockskip_expire; + /* Set to true when the PG_migrate_skip bits should be cleared */ + bool compact_blockskip_flush; /* pfns where compaction scanners should start */ unsigned long compact_cached_free_pfn; diff --git a/mm/compaction.c b/mm/compaction.c index f94cbc0..d8187f9 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -66,24 +66,15 @@ static inline bool isolation_suitable(struct compact_control *cc, * should be skipped for page isolation when the migrate and free page scanner * meet. */ -static void reset_isolation_suitable(struct zone *zone) +static void __reset_isolation_suitable(struct zone *zone) { unsigned long start_pfn = zone->zone_start_pfn; unsigned long end_pfn = zone->zone_start_pfn + zone->spanned_pages; unsigned long pfn; - /* - * Do not reset more than once every five seconds. If allocations are - * failing sufficiently quickly to allow this to happen then continually - * scanning for compaction is not going to help. The choice of five - * seconds is arbitrary but will mitigate excessive scanning. - */ - if (time_before(jiffies, zone->compact_blockskip_expire)) - return; - zone->compact_cached_migrate_pfn = start_pfn; zone->compact_cached_free_pfn = end_pfn; - zone->compact_blockskip_expire = jiffies + (HZ * 5); + zone->compact_blockskip_flush = false; /* Walk the zone and mark every pageblock as suitable for isolation */ for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) { @@ -102,9 +93,24 @@ static void reset_isolation_suitable(struct zone *zone) } } +void reset_isolation_suitable(pg_data_t *pgdat) +{ + int zoneid; + + for (zoneid = 0; zoneid < MAX_NR_ZONES; zoneid++) { + struct zone *zone = &pgdat->node_zones[zoneid]; + if (!populated_zone(zone)) + continue; + + /* Only flush if a full compaction finished recently */ + if (zone->compact_blockskip_flush) + __reset_isolation_suitable(zone); + } +} + /* * If no pages were isolated then mark this pageblock to be skipped in the - * future. The information is later cleared by reset_isolation_suitable(). + * future. The information is later cleared by __reset_isolation_suitable(). */ static void update_pageblock_skip(struct compact_control *cc, struct page *page, unsigned long nr_isolated, @@ -820,7 +826,15 @@ static int compact_finished(struct zone *zone, /* Compaction run completes if the migrate and free scanner meet */ if (cc->free_pfn <= cc->migrate_pfn) { - reset_isolation_suitable(cc->zone); + /* + * Mark that the PG_migrate_skip information should be cleared + * by kswapd when it goes to sleep. kswapd does not set the + * flag itself as the decision to be clear should be directly + * based on an allocation request. + */ + if (!current_is_kswapd()) + zone->compact_blockskip_flush = true; + return COMPACT_COMPLETE; } @@ -943,9 +957,13 @@ static int compact_zone(struct zone *zone, struct compact_control *cc) zone->compact_cached_migrate_pfn = cc->migrate_pfn; } - /* Clear pageblock skip if there are numerous alloc failures */ - if (zone->compact_defer_shift == COMPACT_MAX_DEFER_SHIFT) - reset_isolation_suitable(zone); + /* + * Clear pageblock skip if there were failures recently and compaction + * is about to be retried after being deferred. kswapd does not do + * this reset as it'll reset the cached information when going to sleep. + */ + if (compaction_restarting(zone, cc->order) && !current_is_kswapd()) + __reset_isolation_suitable(zone); migrate_prep_local(); diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 44c5604..b97cf12 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -2172,6 +2172,7 @@ __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order, preferred_zone, migratetype); if (page) { got_page: + preferred_zone->compact_blockskip_flush = false; preferred_zone->compact_considered = 0; preferred_zone->compact_defer_shift = 0; if (order >= preferred_zone->compact_order_failed) diff --git a/mm/vmscan.c b/mm/vmscan.c index 1ee4b69..b010efc 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -2895,6 +2895,14 @@ static void kswapd_try_to_sleep(pg_data_t *pgdat, int order, int classzone_idx) */ set_pgdat_percpu_threshold(pgdat, calculate_normal_threshold); + /* + * Compaction records what page blocks it recently failed to + * isolate pages from and skips them in the future scanning. + * When kswapd is going to sleep, it is reasonable to assume + * that pages and compaction may succeed so reset the cache. + */ + reset_isolation_suitable(pgdat); + if (!kthread_should_stop()) schedule(); |
