diff options
| -rw-r--r-- | include/linux/compaction.h | 19 | ||||
| -rw-r--r-- | mm/compaction.c | 142 | ||||
| -rw-r--r-- | mm/internal.h | 9 | ||||
| -rw-r--r-- | mm/page_alloc.c | 8 |
4 files changed, 150 insertions, 28 deletions
diff --git a/include/linux/compaction.h b/include/linux/compaction.h index 51a90b7f2d6..e988037abd2 100644 --- a/include/linux/compaction.h +++ b/include/linux/compaction.h @@ -1,6 +1,8 @@ #ifndef _LINUX_COMPACTION_H #define _LINUX_COMPACTION_H +#include <linux/node.h> + /* Return values for compact_zone() and try_to_compact_pages() */ /* compaction didn't start as it was not possible or direct reclaim was more suitable */ #define COMPACT_SKIPPED 0 @@ -11,6 +13,23 @@ /* The full zone was compacted */ #define COMPACT_COMPLETE 3 +/* + * compaction supports three modes + * + * COMPACT_ASYNC_MOVABLE uses asynchronous migration and only scans + * MIGRATE_MOVABLE pageblocks as migration sources and targets. + * COMPACT_ASYNC_UNMOVABLE uses asynchronous migration and only scans + * MIGRATE_MOVABLE pageblocks as migration sources. + * MIGRATE_UNMOVABLE pageblocks are scanned as potential migration + * targets and convers them to MIGRATE_MOVABLE if possible + * COMPACT_SYNC uses synchronous migration and scans all pageblocks + */ +enum compact_mode { + COMPACT_ASYNC_MOVABLE, + COMPACT_ASYNC_UNMOVABLE, + COMPACT_SYNC, +}; + #ifdef CONFIG_COMPACTION extern int sysctl_compact_memory; extern int sysctl_compaction_handler(struct ctl_table *table, int write, diff --git a/mm/compaction.c b/mm/compaction.c index da7d35ea510..840ee288e29 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -235,7 +235,7 @@ isolate_migratepages_range(struct zone *zone, struct compact_control *cc, */ while (unlikely(too_many_isolated(zone))) { /* async migration should just abort */ - if (!cc->sync) + if (cc->mode != COMPACT_SYNC) return 0; congestion_wait(BLK_RW_ASYNC, HZ/10); @@ -303,7 +303,8 @@ isolate_migratepages_range(struct zone *zone, struct compact_control *cc, * satisfies the allocation */ pageblock_nr = low_pfn >> pageblock_order; - if (!cc->sync && last_pageblock_nr != pageblock_nr && + if (cc->mode != COMPACT_SYNC && + last_pageblock_nr != pageblock_nr && !migrate_async_suitable(get_pageblock_migratetype(page))) { low_pfn += pageblock_nr_pages; low_pfn = ALIGN(low_pfn, pageblock_nr_pages) - 1; @@ -324,7 +325,7 @@ isolate_migratepages_range(struct zone *zone, struct compact_control *cc, continue; } - if (!cc->sync) + if (cc->mode != COMPACT_SYNC) mode |= ISOLATE_ASYNC_MIGRATE; /* Try isolate the page */ @@ -357,27 +358,90 @@ isolate_migratepages_range(struct zone *zone, struct compact_control *cc, #endif /* CONFIG_COMPACTION || CONFIG_CMA */ #ifdef CONFIG_COMPACTION +/* + * Returns true if MIGRATE_UNMOVABLE pageblock was successfully + * converted to MIGRATE_MOVABLE type, false otherwise. + */ +static bool rescue_unmovable_pageblock(struct page *page) +{ + unsigned long pfn, start_pfn, end_pfn; + struct page *start_page, *end_page; + + pfn = page_to_pfn(page); + start_pfn = pfn & ~(pageblock_nr_pages - 1); + end_pfn = start_pfn + pageblock_nr_pages; + + start_page = pfn_to_page(start_pfn); + end_page = pfn_to_page(end_pfn); + + /* Do not deal with pageblocks that overlap zones */ + if (page_zone(start_page) != page_zone(end_page)) + return false; + + for (page = start_page, pfn = start_pfn; page < end_page; pfn++, + page++) { + if (!pfn_valid_within(pfn)) + continue; + + if (PageBuddy(page)) { + int order = page_order(page); + + pfn += (1 << order) - 1; + page += (1 << order) - 1; + + continue; + } else if (page_count(page) == 0 || PageLRU(page)) + continue; + + return false; + } + + set_pageblock_migratetype(page, MIGRATE_MOVABLE); + move_freepages_block(page_zone(page), page, MIGRATE_MOVABLE); + return true; +} -/* Returns true if the page is within a block suitable for migration to */ -static bool suitable_migration_target(struct page *page) +enum smt_result { + GOOD_AS_MIGRATION_TARGET, + FAIL_UNMOVABLE_TARGET, + FAIL_BAD_TARGET, +}; + +/* + * Returns GOOD_AS_MIGRATION_TARGET if the page is within a block + * suitable for migration to, FAIL_UNMOVABLE_TARGET if the page + * is within a MIGRATE_UNMOVABLE block, FAIL_BAD_TARGET otherwise. + */ +static enum smt_result suitable_migration_target(struct page *page, + struct compact_control *cc) { int migratetype = get_pageblock_migratetype(page); /* Don't interfere with memory hot-remove or the min_free_kbytes blocks */ if (migratetype == MIGRATE_ISOLATE || migratetype == MIGRATE_RESERVE) - return false; + return FAIL_BAD_TARGET; /* If the page is a large free page, then allow migration */ if (PageBuddy(page) && page_order(page) >= pageblock_order) - return true; + return GOOD_AS_MIGRATION_TARGET; /* If the block is MIGRATE_MOVABLE or MIGRATE_CMA, allow migration */ - if (migrate_async_suitable(migratetype)) - return true; + if (cc->mode != COMPACT_ASYNC_UNMOVABLE && + migrate_async_suitable(migratetype)) + return GOOD_AS_MIGRATION_TARGET; + + if (cc->mode == COMPACT_ASYNC_MOVABLE && + migratetype == MIGRATE_UNMOVABLE) + return FAIL_UNMOVABLE_TARGET; + + if (cc->mode != COMPACT_ASYNC_MOVABLE && + migratetype == MIGRATE_UNMOVABLE && + rescue_unmovable_pageblock(page)) + return GOOD_AS_MIGRATION_TARGET; /* Otherwise skip the block */ - return false; + return FAIL_BAD_TARGET; } /* @@ -411,6 +475,13 @@ static void isolate_freepages(struct zone *zone, zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages; /* + * isolate_freepages() may be called more than once during + * compact_zone_order() run and we want only the most recent + * count. + */ + cc->nr_pageblocks_skipped = 0; + + /* * Isolate free pages until enough are available to migrate the * pages on cc->migratepages. We stop searching if the migrate * and free page scanners meet or enough free pages are isolated. @@ -418,6 +489,7 @@ static void isolate_freepages(struct zone *zone, for (; pfn > low_pfn && cc->nr_migratepages > nr_freepages; pfn -= pageblock_nr_pages) { unsigned long isolated; + enum smt_result ret; if (!pfn_valid(pfn)) continue; @@ -434,9 +506,12 @@ static void isolate_freepages(struct zone *zone, continue; /* Check the block is suitable for migration */ - if (!suitable_migration_target(page)) + ret = suitable_migration_target(page, cc); + if (ret != GOOD_AS_MIGRATION_TARGET) { + if (ret == FAIL_UNMOVABLE_TARGET) + cc->nr_pageblocks_skipped++; continue; - + } /* * Found a block suitable for isolating free pages from. Now * we disabled interrupts, double check things are ok and @@ -445,12 +520,14 @@ static void isolate_freepages(struct zone *zone, */ isolated = 0; spin_lock_irqsave(&zone->lock, flags); - if (suitable_migration_target(page)) { + ret = suitable_migration_target(page, cc); + if (ret == GOOD_AS_MIGRATION_TARGET) { end_pfn = min(pfn + pageblock_nr_pages, zone_end_pfn); isolated = isolate_freepages_block(pfn, end_pfn, freelist, false); nr_freepages += isolated; - } + } else if (ret == FAIL_UNMOVABLE_TARGET) + cc->nr_pageblocks_skipped++; spin_unlock_irqrestore(&zone->lock, flags); /* @@ -682,8 +759,9 @@ static int compact_zone(struct zone *zone, struct compact_control *cc) nr_migrate = cc->nr_migratepages; err = migrate_pages(&cc->migratepages, compaction_alloc, - (unsigned long)cc, false, - cc->sync ? MIGRATE_SYNC_LIGHT : MIGRATE_ASYNC); + (unsigned long)&cc->freepages, false, + (cc->mode == COMPACT_SYNC) ? MIGRATE_SYNC_LIGHT + : MIGRATE_ASYNC); update_nr_listpages(cc); nr_remaining = cc->nr_migratepages; @@ -712,7 +790,8 @@ out: static unsigned long compact_zone_order(struct zone *zone, int order, gfp_t gfp_mask, - bool sync) + enum compact_mode mode, + unsigned long *nr_pageblocks_skipped) { struct compact_control cc = { .nr_freepages = 0, @@ -720,12 +799,17 @@ static unsigned long compact_zone_order(struct zone *zone, .order = order, .migratetype = allocflags_to_migratetype(gfp_mask), .zone = zone, - .sync = sync, + .mode = mode, }; + unsigned long rc; + INIT_LIST_HEAD(&cc.freepages); INIT_LIST_HEAD(&cc.migratepages); - return compact_zone(zone, &cc); + rc = compact_zone(zone, &cc); + *nr_pageblocks_skipped = cc.nr_pageblocks_skipped; + + return rc; } int sysctl_extfrag_threshold = 500; @@ -750,6 +834,8 @@ unsigned long try_to_compact_pages(struct zonelist *zonelist, struct zoneref *z; struct zone *zone; int rc = COMPACT_SKIPPED; + unsigned long nr_pageblocks_skipped; + enum compact_mode mode; /* * Check whether it is worth even starting compaction. The order check is @@ -766,12 +852,22 @@ unsigned long try_to_compact_pages(struct zonelist *zonelist, nodemask) { int status; - status = compact_zone_order(zone, order, gfp_mask, sync); + mode = sync ? COMPACT_SYNC : COMPACT_ASYNC_MOVABLE; +retry: + status = compact_zone_order(zone, order, gfp_mask, mode, + &nr_pageblocks_skipped); rc = max(status, rc); /* If a normal allocation would succeed, stop compacting */ if (zone_watermark_ok(zone, order, low_wmark_pages(zone), 0, 0)) break; + + if (rc == COMPACT_COMPLETE && mode == COMPACT_ASYNC_MOVABLE) { + if (nr_pageblocks_skipped) { + mode = COMPACT_ASYNC_UNMOVABLE; + goto retry; + } + } } return rc; @@ -805,7 +901,7 @@ static int __compact_pgdat(pg_data_t *pgdat, struct compact_control *cc) if (ok && cc->order > zone->compact_order_failed) zone->compact_order_failed = cc->order + 1; /* Currently async compaction is never deferred. */ - else if (!ok && cc->sync) + else if (!ok && cc->mode == COMPACT_SYNC) defer_compaction(zone, cc->order); } @@ -820,7 +916,7 @@ int compact_pgdat(pg_data_t *pgdat, int order) { struct compact_control cc = { .order = order, - .sync = false, + .mode = COMPACT_ASYNC_MOVABLE, }; return __compact_pgdat(pgdat, &cc); @@ -830,7 +926,7 @@ static int compact_node(int nid) { struct compact_control cc = { .order = -1, - .sync = true, + .mode = COMPACT_SYNC, }; return __compact_pgdat(NODE_DATA(nid), &cc); diff --git a/mm/internal.h b/mm/internal.h index 8b0fc8da802..4194ab9dc19 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -94,6 +94,9 @@ extern void putback_lru_page(struct page *page); /* * in mm/page_alloc.c */ +extern void set_pageblock_migratetype(struct page *page, int migratetype); +extern int move_freepages_block(struct zone *zone, struct page *page, + int migratetype); extern void __free_pages_bootmem(struct page *page, unsigned int order); extern void prep_compound_page(struct page *page, unsigned long order); #ifdef CONFIG_MEMORY_FAILURE @@ -101,6 +104,7 @@ extern bool is_free_buddy_page(struct page *page); #endif #if defined CONFIG_COMPACTION || defined CONFIG_CMA +#include <linux/compaction.h> /* * in mm/compaction.c @@ -119,11 +123,14 @@ struct compact_control { unsigned long nr_migratepages; /* Number of pages to migrate */ unsigned long free_pfn; /* isolate_freepages search base */ unsigned long migrate_pfn; /* isolate_migratepages search base */ - bool sync; /* Synchronous migration */ + enum compact_mode mode; /* Compaction mode */ int order; /* order a direct compactor needs */ int migratetype; /* MOVABLE, RECLAIMABLE etc */ struct zone *zone; + + /* Number of UNMOVABLE destination pageblocks skipped during scan */ + unsigned long nr_pageblocks_skipped; }; unsigned long diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 84f2c599d5d..457b4de122f 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -219,7 +219,7 @@ EXPORT_SYMBOL(nr_online_nodes); int page_group_by_mobility_disabled __read_mostly; -static void set_pageblock_migratetype(struct page *page, int migratetype) +void set_pageblock_migratetype(struct page *page, int migratetype) { if (unlikely(page_group_by_mobility_disabled)) @@ -954,8 +954,8 @@ static int move_freepages(struct zone *zone, return pages_moved; } -static int move_freepages_block(struct zone *zone, struct page *page, - int migratetype) +int move_freepages_block(struct zone *zone, struct page *page, + int migratetype) { unsigned long start_pfn, end_pfn; struct page *start_page, *end_page; @@ -5657,7 +5657,7 @@ static int __alloc_contig_migrate_range(unsigned long start, unsigned long end) .nr_migratepages = 0, .order = -1, .zone = page_zone(pfn_to_page(start)), - .sync = true, + .mode = COMPACT_SYNC, }; INIT_LIST_HEAD(&cc.migratepages); |