diff options
Diffstat (limited to 'mm/compaction.c')
| -rw-r--r-- | mm/compaction.c | 88 |
1 files changed, 78 insertions, 10 deletions
diff --git a/mm/compaction.c b/mm/compaction.c index 7168edc7592..0fbc6b73a52 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -91,6 +91,60 @@ static inline bool compact_trylock_irqsave(spinlock_t *lock, return compact_checklock_irqsave(lock, flags, false, cc); } +static void compact_capture_page(struct compact_control *cc) +{ + unsigned long flags; + int mtype, mtype_low, mtype_high; + + if (!cc->page || *cc->page) + return; + + /* + * For MIGRATE_MOVABLE allocations we capture a suitable page ASAP + * regardless of the migratetype of the freelist is is captured from. + * This is fine because the order for a high-order MIGRATE_MOVABLE + * allocation is typically at least a pageblock size and overall + * fragmentation is not impaired. Other allocation types must + * capture pages from their own migratelist because otherwise they + * could pollute other pageblocks like MIGRATE_MOVABLE with + * difficult to move pages and making fragmentation worse overall. + */ + if (cc->migratetype == MIGRATE_MOVABLE) { + mtype_low = 0; + mtype_high = MIGRATE_PCPTYPES; + } else { + mtype_low = cc->migratetype; + mtype_high = cc->migratetype + 1; + } + + /* Speculatively examine the free lists without zone lock */ + for (mtype = mtype_low; mtype < mtype_high; mtype++) { + int order; + for (order = cc->order; order < MAX_ORDER; order++) { + struct page *page; + struct free_area *area; + area = &(cc->zone->free_area[order]); + if (list_empty(&area->free_list[mtype])) + continue; + + /* Take the lock and attempt capture of the page */ + if (!compact_trylock_irqsave(&cc->zone->lock, &flags, cc)) + return; + if (!list_empty(&area->free_list[mtype])) { + page = list_entry(area->free_list[mtype].next, + struct page, lru); + if (capture_free_page(page, cc->order, mtype)) { + spin_unlock_irqrestore(&cc->zone->lock, + flags); + *cc->page = page; + return; + } + } + spin_unlock_irqrestore(&cc->zone->lock, flags); + } + } +} + /* * Isolate free pages onto a private freelist. Caller must hold zone->lock. * If @strict is true, will abort returning 0 on any invalid PFNs or non-free @@ -645,7 +699,6 @@ static isolate_migrate_t isolate_migratepages(struct zone *zone, static int compact_finished(struct zone *zone, struct compact_control *cc) { - unsigned int order; unsigned long watermark; if (fatal_signal_pending(current)) @@ -688,14 +741,22 @@ static int compact_finished(struct zone *zone, return COMPACT_CONTINUE; /* Direct compactor: Is a suitable page free? */ - for (order = cc->order; order < MAX_ORDER; order++) { - /* Job done if page is free of the right migratetype */ - if (!list_empty(&zone->free_area[order].free_list[cc->migratetype])) + if (cc->page) { + /* Was a suitable page captured? */ + if (*cc->page) return COMPACT_PARTIAL; + } else { + unsigned int order; + for (order = cc->order; order < MAX_ORDER; order++) { + struct free_area *area = &zone->free_area[cc->order]; + /* Job done if page is free of the right migratetype */ + if (!list_empty(&area->free_list[cc->migratetype])) + return COMPACT_PARTIAL; - /* Job done if allocation would set block type */ - if (order >= pageblock_order && zone->free_area[order].nr_free) - return COMPACT_PARTIAL; + /* Job done if allocation would set block type */ + if (cc->order >= pageblock_order && area->nr_free) + return COMPACT_PARTIAL; + } } return COMPACT_CONTINUE; @@ -817,6 +878,9 @@ static int compact_zone(struct zone *zone, struct compact_control *cc) goto out; } } + + /* Capture a page now if it is a suitable size */ + compact_capture_page(cc); } out: @@ -829,7 +893,8 @@ out: static unsigned long compact_zone_order(struct zone *zone, int order, gfp_t gfp_mask, - bool sync, bool *contended) + bool sync, bool *contended, + struct page **page) { struct compact_control cc = { .nr_freepages = 0, @@ -839,6 +904,7 @@ static unsigned long compact_zone_order(struct zone *zone, .zone = zone, .sync = sync, .contended = contended, + .page = page, }; INIT_LIST_HEAD(&cc.freepages); INIT_LIST_HEAD(&cc.migratepages); @@ -860,7 +926,7 @@ int sysctl_extfrag_threshold = 500; */ unsigned long try_to_compact_pages(struct zonelist *zonelist, int order, gfp_t gfp_mask, nodemask_t *nodemask, - bool sync, bool *contended) + bool sync, bool *contended, struct page **page) { enum zone_type high_zoneidx = gfp_zone(gfp_mask); int may_enter_fs = gfp_mask & __GFP_FS; @@ -881,7 +947,7 @@ unsigned long try_to_compact_pages(struct zonelist *zonelist, int status; status = compact_zone_order(zone, order, gfp_mask, sync, - contended); + contended, page); rc = max(status, rc); /* If a normal allocation would succeed, stop compacting */ @@ -936,6 +1002,7 @@ int compact_pgdat(pg_data_t *pgdat, int order) struct compact_control cc = { .order = order, .sync = false, + .page = NULL, }; return __compact_pgdat(pgdat, &cc); @@ -946,6 +1013,7 @@ static int compact_node(int nid) struct compact_control cc = { .order = -1, .sync = true, + .page = NULL, }; return __compact_pgdat(NODE_DATA(nid), &cc); |