diff options
Diffstat (limited to 'mm/compaction.c')
| -rw-r--r-- | mm/compaction.c | 1039 |
1 files changed, 804 insertions, 235 deletions
diff --git a/mm/compaction.c b/mm/compaction.c index ef29490b0f46..f171a83707ce 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -66,7 +66,7 @@ static unsigned long release_freepages(struct list_head *freelist) return high_pfn; } -static void map_pages(struct list_head *list) +static void split_map_pages(struct list_head *list) { unsigned int i, order, nr_pages; struct page *page, *next; @@ -237,6 +237,70 @@ static bool pageblock_skip_persistent(struct page *page) return false; } +static bool +__reset_isolation_pfn(struct zone *zone, unsigned long pfn, bool check_source, + bool check_target) +{ + struct page *page = pfn_to_online_page(pfn); + struct page *end_page; + unsigned long block_pfn; + + if (!page) + return false; + if (zone != page_zone(page)) + return false; + if (pageblock_skip_persistent(page)) + return false; + + /* + * If skip is already cleared do no further checking once the + * restart points have been set. + */ + if (check_source && check_target && !get_pageblock_skip(page)) + return true; + + /* + * If clearing skip for the target scanner, do not select a + * non-movable pageblock as the starting point. + */ + if (!check_source && check_target && + get_pageblock_migratetype(page) != MIGRATE_MOVABLE) + return false; + + /* + * Only clear the hint if a sample indicates there is either a + * free page or an LRU page in the block. One or other condition + * is necessary for the block to be a migration source/target. + */ + block_pfn = pageblock_start_pfn(pfn); + pfn = max(block_pfn, zone->zone_start_pfn); + page = pfn_to_page(pfn); + if (zone != page_zone(page)) + return false; + pfn = block_pfn + pageblock_nr_pages; + pfn = min(pfn, zone_end_pfn(zone)); + end_page = pfn_to_page(pfn); + + do { + if (pfn_valid_within(pfn)) { + if (check_source && PageLRU(page)) { + clear_pageblock_skip(page); + return true; + } + + if (check_target && PageBuddy(page)) { + clear_pageblock_skip(page); + return true; + } + } + + page += (1 << PAGE_ALLOC_COSTLY_ORDER); + pfn += (1 << PAGE_ALLOC_COSTLY_ORDER); + } while (page < end_page); + + return false; +} + /* * This function is called to clear all cached information on pageblocks that * should be skipped for page isolation when the migrate and free page scanner @@ -244,30 +308,54 @@ static bool pageblock_skip_persistent(struct page *page) */ static void __reset_isolation_suitable(struct zone *zone) { - unsigned long start_pfn = zone->zone_start_pfn; - unsigned long end_pfn = zone_end_pfn(zone); - unsigned long pfn; + unsigned long migrate_pfn = zone->zone_start_pfn; + unsigned long free_pfn = zone_end_pfn(zone); + unsigned long reset_migrate = free_pfn; + unsigned long reset_free = migrate_pfn; + bool source_set = false; + bool free_set = false; + + if (!zone->compact_blockskip_flush) + return; 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) { - struct page *page; - + /* + * Walk the zone and update pageblock skip information. Source looks + * for PageLRU while target looks for PageBuddy. When the scanner + * is found, both PageBuddy and PageLRU are checked as the pageblock + * is suitable as both source and target. + */ + for (; migrate_pfn < free_pfn; migrate_pfn += pageblock_nr_pages, + free_pfn -= pageblock_nr_pages) { cond_resched(); - page = pfn_to_online_page(pfn); - if (!page) - continue; - if (zone != page_zone(page)) - continue; - if (pageblock_skip_persistent(page)) - continue; + /* Update the migrate PFN */ + if (__reset_isolation_pfn(zone, migrate_pfn, true, source_set) && + migrate_pfn < reset_migrate) { + source_set = true; + reset_migrate = migrate_pfn; + zone->compact_init_migrate_pfn = reset_migrate; + zone->compact_cached_migrate_pfn[0] = reset_migrate; + zone->compact_cached_migrate_pfn[1] = reset_migrate; + } - clear_pageblock_skip(page); + /* Update the free PFN */ + if (__reset_isolation_pfn(zone, free_pfn, free_set, true) && + free_pfn > reset_free) { + free_set = true; + reset_free = free_pfn; + zone->compact_init_free_pfn = reset_free; + zone->compact_cached_free_pfn = reset_free; + } } - reset_cached_positions(zone); + /* Leave no distance if no suitable block was reset */ + if (reset_migrate >= reset_free) { + zone->compact_cached_migrate_pfn[0] = migrate_pfn; + zone->compact_cached_migrate_pfn[1] = migrate_pfn; + zone->compact_cached_free_pfn = free_pfn; + } } void reset_isolation_suitable(pg_data_t *pgdat) @@ -286,15 +374,53 @@ void reset_isolation_suitable(pg_data_t *pgdat) } /* + * Sets the pageblock skip bit if it was clear. Note that this is a hint as + * locks are not required for read/writers. Returns true if it was already set. + */ +static bool test_and_set_skip(struct compact_control *cc, struct page *page, + unsigned long pfn) +{ + bool skip; + + /* Do no update if skip hint is being ignored */ + if (cc->ignore_skip_hint) + return false; + + if (!IS_ALIGNED(pfn, pageblock_nr_pages)) + return false; + + skip = get_pageblock_skip(page); + if (!skip && !cc->no_set_skip_hint) + set_pageblock_skip(page); + + return skip; +} + +static void update_cached_migrate(struct compact_control *cc, unsigned long pfn) +{ + struct zone *zone = cc->zone; + + pfn = pageblock_end_pfn(pfn); + + /* Set for isolation rather than compaction */ + if (cc->no_set_skip_hint) + return; + + if (pfn > zone->compact_cached_migrate_pfn[0]) + zone->compact_cached_migrate_pfn[0] = pfn; + if (cc->mode != MIGRATE_ASYNC && + pfn > zone->compact_cached_migrate_pfn[1]) + zone->compact_cached_migrate_pfn[1] = pfn; +} + +/* * If no pages were isolated then mark this pageblock to be skipped in the * 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, - bool migrate_scanner) + struct page *page, unsigned long pfn) { struct zone *zone = cc->zone; - unsigned long pfn; if (cc->no_set_skip_hint) return; @@ -302,24 +428,11 @@ static void update_pageblock_skip(struct compact_control *cc, if (!page) return; - if (nr_isolated) - return; - set_pageblock_skip(page); - pfn = page_to_pfn(page); - /* Update where async and sync compaction should restart */ - if (migrate_scanner) { - if (pfn > zone->compact_cached_migrate_pfn[0]) - zone->compact_cached_migrate_pfn[0] = pfn; - if (cc->mode != MIGRATE_ASYNC && - pfn > zone->compact_cached_migrate_pfn[1]) - zone->compact_cached_migrate_pfn[1] = pfn; - } else { - if (pfn < zone->compact_cached_free_pfn) - zone->compact_cached_free_pfn = pfn; - } + if (pfn < zone->compact_cached_free_pfn) + zone->compact_cached_free_pfn = pfn; } #else static inline bool isolation_suitable(struct compact_control *cc, @@ -334,32 +447,42 @@ static inline bool pageblock_skip_persistent(struct page *page) } static inline void update_pageblock_skip(struct compact_control *cc, - struct page *page, unsigned long nr_isolated, - bool migrate_scanner) + struct page *page, unsigned long pfn) +{ +} + +static void update_cached_migrate(struct compact_control *cc, unsigned long pfn) +{ +} + +static bool test_and_set_skip(struct compact_control *cc, struct page *page, + unsigned long pfn) { + return false; } #endif /* CONFIG_COMPACTION */ /* * Compaction requires the taking of some coarse locks that are potentially - * very heavily contended. For async compaction, back out if the lock cannot - * be taken immediately. For sync compaction, spin on the lock if needed. + * very heavily contended. For async compaction, trylock and record if the + * lock is contended. The lock will still be acquired but compaction will + * abort when the current block is finished regardless of success rate. + * Sync compaction acquires the lock. * - * Returns true if the lock is held - * Returns false if the lock is not held and compaction should abort + * Always returns true which makes it easier to track lock state in callers. */ -static bool compact_trylock_irqsave(spinlock_t *lock, unsigned long *flags, +static bool compact_lock_irqsave(spinlock_t *lock, unsigned long *flags, struct compact_control *cc) { - if (cc->mode == MIGRATE_ASYNC) { - if (!spin_trylock_irqsave(lock, *flags)) { - cc->contended = true; - return false; - } - } else { - spin_lock_irqsave(lock, *flags); + /* Track if the lock is contended in async mode */ + if (cc->mode == MIGRATE_ASYNC && !cc->contended) { + if (spin_trylock_irqsave(lock, *flags)) + return true; + + cc->contended = true; } + spin_lock_irqsave(lock, *flags); return true; } @@ -391,37 +514,7 @@ static bool compact_unlock_should_abort(spinlock_t *lock, return true; } - if (need_resched()) { - if (cc->mode == MIGRATE_ASYNC) { - cc->contended = true; - return true; - } - cond_resched(); - } - - return false; -} - -/* - * Aside from avoiding lock contention, compaction also periodically checks - * need_resched() and either schedules in sync compaction or aborts async - * compaction. This is similar to what compact_unlock_should_abort() does, but - * is used where no lock is concerned. - * - * Returns false when no scheduling was needed, or sync compaction scheduled. - * Returns true when async compaction should abort. - */ -static inline bool compact_should_abort(struct compact_control *cc) -{ - /* async compaction aborts if contended */ - if (need_resched()) { - if (cc->mode == MIGRATE_ASYNC) { - cc->contended = true; - return true; - } - - cond_resched(); - } + cond_resched(); return false; } @@ -435,19 +528,24 @@ static unsigned long isolate_freepages_block(struct compact_control *cc, unsigned long *start_pfn, unsigned long end_pfn, struct list_head *freelist, + unsigned int stride, bool strict) { int nr_scanned = 0, total_isolated = 0; - struct page *cursor, *valid_page = NULL; + struct page *cursor; unsigned long flags = 0; bool locked = false; unsigned long blockpfn = *start_pfn; unsigned int order; + /* Strict mode is for isolation, speed is secondary */ + if (strict) + stride = 1; + cursor = pfn_to_page(blockpfn); /* Isolate free pages. */ - for (; blockpfn < end_pfn; blockpfn++, cursor++) { + for (; blockpfn < end_pfn; blockpfn += stride, cursor += stride) { int isolated; struct page *page = cursor; @@ -465,9 +563,6 @@ static unsigned long isolate_freepages_block(struct compact_control *cc, if (!pfn_valid_within(blockpfn)) goto isolate_fail; - if (!valid_page) - valid_page = page; - /* * For compound pages such as THP and hugetlbfs, we can save * potentially a lot of iterations if we skip them at once. @@ -495,18 +590,8 @@ static unsigned long isolate_freepages_block(struct compact_control *cc, * recheck as well. */ if (!locked) { - /* - * The zone lock must be held to isolate freepages. - * Unfortunately this is a very coarse lock and can be - * heavily contended if there are parallel allocations - * or parallel compactions. For async compaction do not - * spin on the lock and we acquire the lock as late as - * possible. - */ - locked = compact_trylock_irqsave(&cc->zone->lock, + locked = compact_lock_irqsave(&cc->zone->lock, &flags, cc); - if (!locked) - break; /* Recheck this is a buddy page under lock */ if (!PageBuddy(page)) @@ -565,10 +650,6 @@ isolate_fail: if (strict && blockpfn < end_pfn) total_isolated = 0; - /* Update the pageblock-skip if the whole pageblock was scanned */ - if (blockpfn == end_pfn) - update_pageblock_skip(cc, valid_page, total_isolated, false); - cc->total_free_scanned += nr_scanned; if (total_isolated) count_compact_events(COMPACTISOLATED, total_isolated); @@ -626,7 +707,7 @@ isolate_freepages_range(struct compact_control *cc, break; isolated = isolate_freepages_block(cc, &isolate_start_pfn, - block_end_pfn, &freelist, true); + block_end_pfn, &freelist, 0, true); /* * In strict mode, isolate_freepages_block() returns 0 if @@ -644,7 +725,7 @@ isolate_freepages_range(struct compact_control *cc, } /* __isolate_free_page() does not map the pages */ - map_pages(&freelist); + split_map_pages(&freelist); if (pfn < end_pfn) { /* Loop terminated early, cleanup. */ @@ -657,16 +738,16 @@ isolate_freepages_range(struct compact_control *cc, } /* Similar to reclaim, but different enough that they don't share logic */ -static bool too_many_isolated(struct zone *zone) +static bool too_many_isolated(pg_data_t *pgdat) { unsigned long active, inactive, isolated; - inactive = node_page_state(zone->zone_pgdat, NR_INACTIVE_FILE) + - node_page_state(zone->zone_pgdat, NR_INACTIVE_ANON); - active = node_page_state(zone->zone_pgdat, NR_ACTIVE_FILE) + - node_page_state(zone->zone_pgdat, NR_ACTIVE_ANON); - isolated = node_page_state(zone->zone_pgdat, NR_ISOLATED_FILE) + - node_page_state(zone->zone_pgdat, NR_ISOLATED_ANON); + inactive = node_page_state(pgdat, NR_INACTIVE_FILE) + + node_page_state(pgdat, NR_INACTIVE_ANON); + active = node_page_state(pgdat, NR_ACTIVE_FILE) + + node_page_state(pgdat, NR_ACTIVE_ANON); + isolated = node_page_state(pgdat, NR_ISOLATED_FILE) + + node_page_state(pgdat, NR_ISOLATED_ANON); return isolated > (inactive + active) / 2; } @@ -693,7 +774,7 @@ static unsigned long isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn, unsigned long end_pfn, isolate_mode_t isolate_mode) { - struct zone *zone = cc->zone; + pg_data_t *pgdat = cc->zone->zone_pgdat; unsigned long nr_scanned = 0, nr_isolated = 0; struct lruvec *lruvec; unsigned long flags = 0; @@ -702,13 +783,14 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn, unsigned long start_pfn = low_pfn; bool skip_on_failure = false; unsigned long next_skip_pfn = 0; + bool skip_updated = false; /* * Ensure that there are not too many pages isolated from the LRU * list by either parallel reclaimers or compaction. If there are, * delay for some time until fewer pages are isolated */ - while (unlikely(too_many_isolated(zone))) { + while (unlikely(too_many_isolated(pgdat))) { /* async migration should just abort */ if (cc->mode == MIGRATE_ASYNC) return 0; @@ -719,8 +801,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn, return 0; } - if (compact_should_abort(cc)) - return 0; + cond_resched(); if (cc->direct_compaction && (cc->mode == MIGRATE_ASYNC)) { skip_on_failure = true; @@ -758,8 +839,8 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn, * if contended. */ if (!(low_pfn % SWAP_CLUSTER_MAX) - && compact_unlock_should_abort(zone_lru_lock(zone), flags, - &locked, cc)) + && compact_unlock_should_abort(&pgdat->lru_lock, + flags, &locked, cc)) break; if (!pfn_valid_within(low_pfn)) @@ -768,8 +849,19 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn, page = pfn_to_page(low_pfn); - if (!valid_page) + /* + * Check if the pageblock has already been marked skipped. + * Only the aligned PFN is checked as the caller isolates + * COMPACT_CLUSTER_MAX at a time so the second call must + * not falsely conclude that the block should be skipped. + */ + if (!valid_page && IS_ALIGNED(low_pfn, pageblock_nr_pages)) { + if (!cc->ignore_skip_hint && get_pageblock_skip(page)) { + low_pfn = end_pfn; + goto isolate_abort; + } valid_page = page; + } /* * Skip if free. We read page order here without zone lock @@ -818,7 +910,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn, if (unlikely(__PageMovable(page)) && !PageIsolated(page)) { if (locked) { - spin_unlock_irqrestore(zone_lru_lock(zone), + spin_unlock_irqrestore(&pgdat->lru_lock, flags); locked = false; } @@ -848,10 +940,15 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn, /* If we already hold the lock, we can skip some rechecking */ if (!locked) { - locked = compact_trylock_irqsave(zone_lru_lock(zone), + locked = compact_lock_irqsave(&pgdat->lru_lock, &flags, cc); - if (!locked) - break; + + /* Try get exclusive access under lock */ + if (!skip_updated) { + skip_updated = true; + if (test_and_set_skip(cc, page, low_pfn)) + goto isolate_abort; + } /* Recheck PageLRU and PageCompound under lock */ if (!PageLRU(page)) @@ -868,7 +965,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn, } } - lruvec = mem_cgroup_page_lruvec(page, zone->zone_pgdat); + lruvec = mem_cgroup_page_lruvec(page, pgdat); /* Try isolate the page */ if (__isolate_lru_page(page, isolate_mode) != 0) @@ -887,16 +984,13 @@ isolate_success: nr_isolated++; /* - * Record where we could have freed pages by migration and not - * yet flushed them to buddy allocator. - * - this is the lowest page that was isolated and likely be - * then freed by migration. + * Avoid isolating too much unless this block is being + * rescanned (e.g. dirty/writeback pages, parallel allocation) + * or a lock is contended. For contention, isolate quickly to + * potentially remove one source of contention. */ - if (!cc->last_migrated_pfn) - cc->last_migrated_pfn = low_pfn; - - /* Avoid isolating too much */ - if (cc->nr_migratepages == COMPACT_CLUSTER_MAX) { + if (cc->nr_migratepages == COMPACT_CLUSTER_MAX && + !cc->rescan && !cc->contended) { ++low_pfn; break; } @@ -913,12 +1007,11 @@ isolate_fail: */ if (nr_isolated) { if (locked) { - spin_unlock_irqrestore(zone_lru_lock(zone), flags); + spin_unlock_irqrestore(&pgdat->lru_lock, flags); locked = false; } putback_movable_pages(&cc->migratepages); cc->nr_migratepages = 0; - cc->last_migrated_pfn = 0; nr_isolated = 0; } @@ -939,15 +1032,23 @@ isolate_fail: if (unlikely(low_pfn > end_pfn)) low_pfn = end_pfn; +isolate_abort: if (locked) - spin_unlock_irqrestore(zone_lru_lock(zone), flags); + spin_unlock_irqrestore(&pgdat->lru_lock, flags); /* - * Update the pageblock-skip information and cached scanner pfn, - * if the whole pageblock was scanned without isolating any page. + * Updated the cached scanner pfn once the pageblock has been scanned + * Pages will either be migrated in which case there is no point + * scanning in the near future or migration failed in which case the + * failure reason may persist. The block is marked for skipping if + * there were no pages isolated in the block or if the block is + * rescanned twice in a row. */ - if (low_pfn == end_pfn) - update_pageblock_skip(cc, valid_page, nr_isolated, true); + if (low_pfn == end_pfn && (!nr_isolated || cc->rescan)) { + if (valid_page && !skip_updated) + set_pageblock_skip(valid_page); + update_cached_migrate(cc, low_pfn); + } trace_mm_compaction_isolate_migratepages(start_pfn, low_pfn, nr_scanned, nr_isolated); @@ -1013,6 +1114,9 @@ static bool suitable_migration_source(struct compact_control *cc, { int block_mt; + if (pageblock_skip_persistent(page)) + return false; + if ((cc->mode != MIGRATE_ASYNC) || !cc->direct_compaction) return true; @@ -1050,6 +1154,12 @@ static bool suitable_migration_target(struct compact_control *cc, return false; } +static inline unsigned int +freelist_scan_limit(struct compact_control *cc) +{ + return (COMPACT_CLUSTER_MAX >> cc->fast_search_fail) + 1; +} + /* * Test whether the free scanner has reached the same or lower pageblock than * the migration scanner, and compaction should thus terminate. @@ -1061,6 +1171,248 @@ static inline bool compact_scanners_met(struct compact_control *cc) } /* + * Used when scanning for a suitable migration target which scans freelists + * in reverse. Reorders the list such as the unscanned pages are scanned + * first on the next iteration of the free scanner + */ +static void +move_freelist_head(struct list_head *freelist, struct page *freepage) +{ + LIST_HEAD(sublist); + + if (!list_is_last(freelist, &freepage->lru)) { + list_cut_before(&sublist, freelist, &freepage->lru); + if (!list_empty(&sublist)) + list_splice_tail(&sublist, freelist); + } +} + +/* + * Similar to move_freelist_head except used by the migration scanner + * when scanning forward. It's possible for these list operations to + * move against each other if they search the free list exactly in + * lockstep. + */ +static void +move_freelist_tail(struct list_head *freelist, struct page *freepage) +{ + LIST_HEAD(sublist); + + if (!list_is_first(freelist, &freepage->lru)) { + list_cut_position(&sublist, freelist, &freepage->lru); + if (!list_empty(&sublist)) + list_splice_tail(&sublist, freelist); + } +} + +static void +fast_isolate_around(struct compact_control *cc, unsigned long pfn, unsigned long nr_isolated) +{ + unsigned long start_pfn, end_pfn; + struct page *page = pfn_to_page(pfn); + + /* Do not search around if there are enough pages already */ + if (cc->nr_freepages >= cc->nr_migratepages) + return; + + /* Minimise scanning during async compaction */ + if (cc->direct_compaction && cc->mode == MIGRATE_ASYNC) + return; + + /* Pageblock boundaries */ + start_pfn = pageblock_start_pfn(pfn); + end_pfn = min(start_pfn + pageblock_nr_pages, zone_end_pfn(cc->zone)); + + /* Scan before */ + if (start_pfn != pfn) { + isolate_freepages_block(cc, &start_pfn, pfn, &cc->freepages, 1, false); + if (cc->nr_freepages >= cc->nr_migratepages) + return; + } + + /* Scan after */ + start_pfn = pfn + nr_isolated; + if (start_pfn != end_pfn) + isolate_freepages_block(cc, &start_pfn, end_pfn, &cc->freepages, 1, false); + + /* Skip this pageblock in the future as it's full or nearly full */ + if (cc->nr_freepages < cc->nr_migratepages) + set_pageblock_skip(page); +} + +/* Search orders in round-robin fashion */ +static int next_search_order(struct compact_control *cc, int order) +{ + order--; + if (order < 0) + order = cc->order - 1; + + /* Search wrapped around? */ + if (order == cc->search_order) { + cc->search_order--; + if (cc->search_order < 0) + cc->search_order = cc->order - 1; + return -1; + } + + return order; +} + +static unsigned long +fast_isolate_freepages(struct compact_control *cc) +{ + unsigned int limit = min(1U, freelist_scan_limit(cc) >> 1); + unsigned int nr_scanned = 0; + unsigned long low_pfn, min_pfn, high_pfn = 0, highest = 0; + unsigned long nr_isolated = 0; + unsigned long distance; + struct page *page = NULL; + bool scan_start = false; + int order; + + /* Full compaction passes in a negative order */ + if (cc->order <= 0) + return cc->free_pfn; + + /* + * If starting the scan, use a deeper search and use the highest + * PFN found if a suitable one is not found. + */ + if (cc->free_pfn >= cc->zone->compact_init_free_pfn) { + limit = pageblock_nr_pages >> 1; + scan_start = true; + } + + /* + * Preferred point is in the top quarter of the scan space but take + * a pfn from the top half if the search is problematic. + */ + distance = (cc->free_pfn - cc->migrate_pfn); + low_pfn = pageblock_start_pfn(cc->free_pfn - (distance >> 2)); + min_pfn = pageblock_start_pfn(cc->free_pfn - (distance >> 1)); + + if (WARN_ON_ONCE(min_pfn > low_pfn)) + low_pfn = min_pfn; + + /* + * Search starts from the last successful isolation order or the next + * order to search after a previous failure + */ + cc->search_order = min_t(unsigned int, cc->order - 1, cc->search_order); + + for (order = cc->search_order; + !page && order >= 0; + order = next_search_order(cc, order)) { + struct free_area *area = &cc->zone->free_area[order]; + struct list_head *freelist; + struct page *freepage; + unsigned long flags; + unsigned int order_scanned = 0; + + if (!area->nr_free) + continue; + + spin_lock_irqsave(&cc->zone->lock, flags); + freelist = &area->free_list[MIGRATE_MOVABLE]; + list_for_each_entry_reverse(freepage, freelist, lru) { + unsigned long pfn; + + order_scanned++; + nr_scanned++; + pfn = page_to_pfn(freepage); + + if (pfn >= highest) + highest = pageblock_start_pfn(pfn); + + if (pfn >= low_pfn) { + cc->fast_search_fail = 0; + cc->search_order = order; + page = freepage; + break; + } + + if (pfn >= min_pfn && pfn > high_pfn) { + high_pfn = pfn; + + /* Shorten the scan if a candidate is found */ + limit >>= 1; + } + + if (order_scanned >= limit) + break; + } + + /* Use a minimum pfn if a preferred one was not found */ + if (!page && high_pfn) { + page = pfn_to_page(high_pfn); + + /* Update freepage for the list reorder below */ + freepage = page; + } + + /* Reorder to so a future search skips recent pages */ + move_freelist_head(freelist, freepage); + + /* Isolate the page if available */ + if (page) { + if (__isolate_free_page(page, order)) { + set_page_private(page, order); + nr_isolated = 1 << order; + cc->nr_freepages += nr_isolated; + list_add_tail(&page->lru, &cc->freepages); + count_compact_events(COMPACTISOLATED, nr_isolated); + } else { + /* If isolation fails, abort the search */ + order = -1; + page = NULL; + } + } + + spin_unlock_irqrestore(&cc->zone->lock, flags); + + /* + * Smaller scan on next order so the total scan ig related + * to freelist_scan_limit. + */ + if (order_scanned >= limit) + limit = min(1U, limit >> 1); + } + + if (!page) { + cc->fast_search_fail++; + if (scan_start) { + /* + * Use the highest PFN found above min. If one was + * not found, be pessemistic for direct compaction + * and use the min mark. + */ + if (highest) { + page = pfn_to_page(highest); + cc->free_pfn = highest; + } else { + if (cc->direct_compaction) { + page = pfn_to_page(min_pfn); + cc->free_pfn = min_pfn; + } + } + } + } + + if (highest && highest >= cc->zone->compact_cached_free_pfn) { + highest -= pageblock_nr_pages; + cc->zone->compact_cached_free_pfn = highest; + } + + cc->total_free_scanned += nr_scanned; + if (!page) + return cc->free_pfn; + + low_pfn = page_to_pfn(page); + fast_isolate_around(cc, low_pfn, nr_isolated); + return low_pfn; +} + +/* * Based on information in the current compact_control, find blocks * suitable for isolating free pages from and then isolate them. */ @@ -1073,6 +1425,12 @@ static void isolate_freepages(struct compact_control *cc) unsigned long block_end_pfn; /* end of current pageblock */ unsigned long low_pfn; /* lowest pfn scanner is able to scan */ struct list_head *freelist = &cc->freepages; + unsigned int stride; + + /* Try a small search of the free lists for a candidate */ + isolate_start_pfn = fast_isolate_freepages(cc); + if (cc->nr_freepages) + goto splitmap; /* * Initialise the free scanner. The starting point is where we last @@ -1086,10 +1444,11 @@ static void isolate_freepages(struct compact_control *cc) * is using. */ isolate_start_pfn = cc->free_pfn; - block_start_pfn = pageblock_start_pfn(cc->free_pfn); + block_start_pfn = pageblock_start_pfn(isolate_start_pfn); block_end_pfn = min(block_start_pfn + pageblock_nr_pages, zone_end_pfn(zone)); low_pfn = pageblock_end_pfn(cc->migrate_pfn); + stride = cc->mode == MIGRATE_ASYNC ? COMPACT_CLUSTER_MAX : 1; /* * Isolate free pages until enough are available to migrate the @@ -1100,14 +1459,14 @@ static void isolate_freepages(struct compact_control *cc) block_end_pfn = block_start_pfn, block_start_pfn -= pageblock_nr_pages, isolate_start_pfn = block_start_pfn) { + unsigned long nr_isolated; + /* * This can iterate a massively long zone without finding any - * suitable migration targets, so periodically check if we need - * to schedule, or even abort async compaction. + * suitable migration targets, so periodically check resched. */ - if (!(block_start_pfn % (SWAP_CLUSTER_MAX * pageblock_nr_pages)) - && compact_should_abort(cc)) - break; + if (!(block_start_pfn % (SWAP_CLUSTER_MAX * pageblock_nr_pages))) + cond_resched(); page = pageblock_pfn_to_page(block_start_pfn, block_end_pfn, zone); @@ -1123,15 +1482,15 @@ static void isolate_freepages(struct compact_control *cc) continue; /* Found a block suitable for isolating free pages from. */ - isolate_freepages_block(cc, &isolate_start_pfn, block_end_pfn, - freelist, false); + nr_isolated = isolate_freepages_block(cc, &isolate_start_pfn, + block_end_pfn, freelist, stride, false); - /* - * If we isolated enough freepages, or aborted due to lock - * contention, terminate. - */ - if ((cc->nr_freepages >= cc->nr_migratepages) - || cc->contended) { + /* Update the skip hint if the full pageblock was scanned */ + if (isolate_start_pfn == block_end_pfn) + update_pageblock_skip(cc, page, block_start_pfn); + + /* Are enough freepages isolated? */ + if (cc->nr_freepages >= cc->nr_migratepages) { if (isolate_start_pfn >= block_end_pfn) { /* * Restart at previous pageblock if more @@ -1148,10 +1507,14 @@ static void isolate_freepages(struct compact_control *cc) */ break; } - } - /* __isolate_free_page() does not map the pages */ - map_pages(freelist); + /* Adjust stride depending on isolation */ + if (nr_isolated) { + stride = 1; + continue; + } + stride = min_t(unsigned int, COMPACT_CLUSTER_MAX, stride << 1); + } /* * Record where the free scanner will restart next time. Either we @@ -1160,6 +1523,10 @@ static void isolate_freepages(struct compact_control *cc) * and the loop terminated due to isolate_start_pfn < low_pfn */ cc->free_pfn = isolate_start_pfn; + +splitmap: + /* __isolate_free_page() does not map the pages */ + split_map_pages(freelist); } /* @@ -1172,13 +1539,8 @@ static struct page *compaction_alloc(struct page *migratepage, struct compact_control *cc = (struct compact_control *)data; struct page *freepage; - /* - * Isolate free pages if necessary, and if we are not aborting due to - * contention. - */ if (list_empty(&cc->freepages)) { - if (!cc->contended) - isolate_freepages(cc); + isolate_freepages(cc); if (list_empty(&cc->freepages)) return NULL; @@ -1217,6 +1579,147 @@ typedef enum { */ int sysctl_compact_unevictable_allowed __read_mostly = 1; +static inline void +update_fast_start_pfn(struct compact_control *cc, unsigned long pfn) +{ + if (cc->fast_start_pfn == ULONG_MAX) + return; + + if (!cc->fast_start_pfn) + cc->fast_start_pfn = pfn; + + cc->fast_start_pfn = min(cc->fast_start_pfn, pfn); +} + +static inline unsigned long +reinit_migrate_pfn(struct compact_control *cc) +{ + if (!cc->fast_start_pfn || cc->fast_start_pfn == ULONG_MAX) + return cc->migrate_pfn; + + cc->migrate_pfn = cc->fast_start_pfn; + cc->fast_start_pfn = ULONG_MAX; + + return cc->migrate_pfn; +} + +/* + * Briefly search the free lists for a migration source that already has + * some free pages to reduce the number of pages that need migration + * before a pageblock is free. + */ +static unsigned long fast_find_migrateblock(struct compact_control *cc) +{ + unsigned int limit = freelist_scan_limit(cc); + unsigned int nr_scanned = 0; + unsigned long distance; + unsigned long pfn = cc->migrate_pfn; + unsigned long high_pfn; + int order; + + /* Skip hints are relied on to avoid repeats on the fast search */ + if (cc->ignore_skip_hint) + return pfn; + + /* + * If the migrate_pfn is not at the start of a zone or the start + * of a pageblock then assume this is a continuation of a previous + * scan restarted due to COMPACT_CLUSTER_MAX. + */ + if (pfn != cc->zone->zone_start_pfn && pfn != pageblock_start_pfn(pfn)) + return pfn; + + /* + * For smaller orders, just linearly scan as the number of pages + * to migrate should be relatively small and does not necessarily + * justify freeing up a large block for a small allocation. + */ + if (cc->order <= PAGE_ALLOC_COSTLY_ORDER) + return pfn; + + /* + * Only allow kcompactd and direct requests for movable pages to + * quickly clear out a MOVABLE pageblock for allocation. This + * reduces the risk that a large movable pageblock is freed for + * an unmovable/reclaimable small allocation. + */ + if (cc->direct_compaction && cc->migratetype != MIGRATE_MOVABLE) + return pfn; + + /* + * When starting the migration scanner, pick any pageblock within the + * first half of the search space. Otherwise try and pick a pageblock + * within the first eighth to reduce the chances that a migration + * target later becomes a source. + */ + distance = (cc->free_pfn - cc->migrate_pfn) >> 1; + if (cc->migrate_pfn != cc->zone->zone_start_pfn) + distance >>= 2; + high_pfn = pageblock_start_pfn(cc->migrate_pfn + distance); + + for (order = cc->order - 1; + order >= PAGE_ALLOC_COSTLY_ORDER && pfn == cc->migrate_pfn && nr_scanned < limit; + order--) { + struct free_area *area = &cc->zone->free_area[order]; + struct list_head *freelist; + unsigned long flags; + struct page *freepage; + + if (!area->nr_free) + continue; + + spin_lock_irqsave(&cc->zone->lock, flags); + freelist = &area->free_list[MIGRATE_MOVABLE]; + list_for_each_entry(freepage, freelist, lru) { + unsigned long free_pfn; + + nr_scanned++; + free_pfn = page_to_pfn(freepage); + if (free_pfn < high_pfn) { + /* + * Avoid if skipped recently. Ideally it would + * move to the tail but even safe iteration of + * the list assumes an entry is deleted, not + * reordered. + */ + if (get_pageblock_skip(freepage)) { + if (list_is_last(freelist, &freepage->lru)) + break; + + continue; + } + + /* Reorder to so a future search skips recent pages */ + move_freelist_tail(freelist, freepage); + + update_fast_start_pfn(cc, free_pfn); + pfn = pageblock_start_pfn(free_pfn); + cc->fast_search_fail = 0; + set_pageblock_skip(freepage); + break; + } + + if (nr_scanned >= limit) { + cc->fast_search_fail++; + move_freelist_tail(freelist, freepage); + break; + } + } + spin_unlock_irqrestore(&cc->zone->lock, flags); + } + + cc->total_migrate_scanned += nr_scanned; + + /* + * If fast scanning failed then use a cached entry for a page block + * that had free pages as the basis for starting a linear scan. + */ + if (pfn == cc->migrate_pfn) + pfn = reinit_migrate_pfn(cc); + + return pfn; +} + /* * Isolate all pages that can be migrated from the first suitable block, * starting at the block pointed to by the migrate scanner pfn within @@ -1232,16 +1735,25 @@ static isolate_migrate_t isolate_migratepages(struct zone *zone, const isolate_mode_t isolate_mode = (sysctl_compact_unevictable_allowed ? ISOLATE_UNEVICTABLE : 0) | (cc->mode != MIGRATE_SYNC ? ISOLATE_ASYNC_MIGRATE : 0); + bool fast_find_block; /* * Start at where we last stopped, or beginning of the zone as - * initialized by compact_zone() + * initialized by compact_zone(). The first failure will use + * the lowest PFN as the starting point for linear scanning. */ - low_pfn = cc->migrate_pfn; + low_pfn = fast_find_migrateblock(cc); block_start_pfn = pageblock_start_pfn(low_pfn); if (block_start_pfn < zone->zone_start_pfn) block_start_pfn = zone->zone_start_pfn; + /* + * fast_find_migrateblock marks a pageblock skipped so to avoid + * the isolation_suitable check below, check whether the fast + * search was successful. + */ + fast_find_block = low_pfn != cc->migrate_pfn && !cc->fast_search_fail; + /* Only scan within a pageblock boundary */ block_end_pfn = pageblock_end_pfn(low_pfn); @@ -1250,6 +1762,7 @@ static isolate_migrate_t isolate_migratepages(struct zone *zone, * Do not cross the free scanner. */ for (; block_end_pfn <= cc->free_pfn; + fast_find_block = false, low_pfn = block_end_pfn, block_start_pfn = block_end_pfn, block_end_pfn += pageblock_nr_pages) { @@ -1257,34 +1770,45 @@ static isolate_migrate_t isolate_migratepages(struct zone *zone, /* * This can potentially iterate a massively long zone with * many pageblocks unsuitable, so periodically check if we - * need to schedule, or even abort async compaction. + * need to schedule. */ - if (!(low_pfn % (SWAP_CLUSTER_MAX * pageblock_nr_pages)) - && compact_should_abort(cc)) - break; + if (!(low_pfn % (SWAP_CLUSTER_MAX * pageblock_nr_pages))) + cond_resched(); page = pageblock_pfn_to_page(block_start_pfn, block_end_pfn, zone); if (!page) continue; - /* If isolation recently failed, do not retry */ - if (!isolation_suitable(cc, page)) + /* + * If isolation recently failed, do not retry. Only check the + * pageblock once. COMPACT_CLUSTER_MAX causes a pageblock + * to be visited multiple times. Assume skip was checked + * before making it "skip" so other compaction instances do + * not scan the same block. + */ + if (IS_ALIGNED(low_pfn, pageblock_nr_pages) && + !fast_find_block && !isolation_suitable(cc, page)) continue; /* - * For async compaction, also only scan in MOVABLE blocks. - * Async compaction is optimistic to see if the minimum amount - * of work satisfies the allocation. + * For async compaction, also only scan in MOVABLE blocks + * without huge pages. Async compaction is optimistic to see + * if the minimum amount of work satisfies the allocation. + * The cached PFN is updated as it's possible that all + * remaining blocks between source and target are unsuitable + * and the compaction scanners fail to meet. */ - if (!suitable_migration_source(cc, page)) + if (!suitable_migration_source(cc, page)) { + update_cached_migrate(cc, block_end_pfn); continue; + } /* Perform the isolation */ low_pfn = isolate_migratepages_block(cc, low_pfn, block_end_pfn, isolate_mode); - if (!low_pfn || cc->contended) + if (!low_pfn) return ISOLATE_ABORT; /* @@ -1310,19 +1834,16 @@ static inline bool is_via_compact_memory(int order) return order == -1; } -static enum compact_result __compact_finished(struct zone *zone, - struct compact_control *cc) +static enum compact_result __compact_finished(struct compact_control *cc) { unsigned int order; const int migratetype = cc->migratetype; - - if (cc->contended || fatal_signal_pending(current)) - return COMPACT_CONTENDED; + int ret; /* Compaction run completes if the migrate and free scanner meet */ if (compact_scanners_met(cc)) { /* Let the next compaction start anew. */ - reset_cached_positions(zone); + reset_cached_positions(cc->zone); /* * Mark that the PG_migrate_skip information should be cleared @@ -1331,7 +1852,7 @@ static enum compact_result __compact_finished(struct zone *zone, * based on an allocation request. */ if (cc->direct_compaction) - zone->compact_blockskip_flush = true; + cc->zone->compact_blockskip_flush = true; if (cc->whole_zone) return COMPACT_COMPLETE; @@ -1342,20 +1863,19 @@ static enum compact_result __compact_finished(struct zone *zone, if (is_via_compact_memory(cc->order)) return COMPACT_CONTINUE; - if (cc->finishing_block) { - /* - * We have finished the pageblock, but better check again that - * we really succeeded. - */ - if (IS_ALIGNED(cc->migrate_pfn, pageblock_nr_pages)) - cc->finishing_block = false; - else - return COMPACT_CONTINUE; - } + /* + * Always finish scanning a pageblock to reduce the possibility of + * fallbacks in the future. This is particularly important when + * migration source is unmovable/reclaimable but it's not worth + * special casing. + */ + if (!IS_ALIGNED(cc->migrate_pfn, pageblock_nr_pages)) + return COMPACT_CONTINUE; /* Direct compactor: Is a suitable page free? */ + ret = COMPACT_NO_SUITABLE_PAGE; for (order = cc->order; order < MAX_ORDER; order++) { - struct free_area *area = &zone->free_area[order]; + struct free_area *area = &cc->zone->free_area[order]; bool can_steal; /* Job done if page is free of the right migratetype */ @@ -1393,21 +1913,23 @@ static enum compact_result __compact_finished(struct zone *zone, return COMPACT_SUCCESS; } - cc->finishing_block = true; - return COMPACT_CONTINUE; + ret = COMPACT_CONTINUE; + break; } } - return COMPACT_NO_SUITABLE_PAGE; + if (cc->contended || fatal_signal_pending(current)) + ret = COMPACT_CONTENDED; + + return ret; } -static enum compact_result compact_finished(struct zone *zone, - struct compact_control *cc) +static enum compact_result compact_finished(struct compact_control *cc) { int ret; - ret = __compact_finished(zone, cc); - trace_mm_compaction_finished(zone, cc->order, ret); + ret = __compact_finished(cc); + trace_mm_compaction_finished(cc->zone, cc->order, ret); if (ret == COMPACT_NO_SUITABLE_PAGE) ret = COMPACT_CONTINUE; @@ -1534,15 +2056,18 @@ bool compaction_zonelist_suitable(struct alloc_context *ac, int order, return false; } -static enum compact_result compact_zone(struct zone *zone, struct compact_control *cc) +static enum compact_result +compact_zone(struct compact_control *cc, struct capture_control *capc) { enum compact_result ret; - unsigned long start_pfn = zone->zone_start_pfn; - unsigned long end_pfn = zone_end_pfn(zone); + unsigned long start_pfn = cc->zone->zone_start_pfn; + unsigned long end_pfn = zone_end_pfn(cc->zone); + unsigned long last_migrated_pfn; const bool sync = cc->mode != MIGRATE_ASYNC; + bool update_cached; cc->migratetype = gfpflags_to_migratetype(cc->gfp_mask); - ret = compaction_suitable(zone, cc->order, cc->alloc_flags, + ret = compaction_suitable(cc->zone, cc->order, cc->alloc_flags, cc->classzone_idx); /* Compaction is likely to fail */ if (ret == COMPACT_SUCCESS || ret == COMPACT_SKIPPED) @@ -1555,8 +2080,8 @@ static enum compact_result compact_zone(struct zone *zone, struct compact_contro * Clear pageblock skip if there were failures recently and compaction * is about to be retried after being deferred. */ - if (compaction_restarting(zone, cc->order)) - __reset_isolation_suitable(zone); + if (compaction_restarting(cc->zone, cc->order)) + __reset_isolation_suitable(cc->zone); /* * Setup to move all movable pages to the end of the zone. Used cached @@ -1564,43 +2089,76 @@ static enum compact_result compact_zone(struct zone *zone, struct compact_contro * want to compact the whole zone), but check that it is initialised * by ensuring the values are within zone boundaries. */ + cc->fast_start_pfn = 0; if (cc->whole_zone) { cc->migrate_pfn = start_pfn; cc->free_pfn = pageblock_start_pfn(end_pfn - 1); } else { - cc->migrate_pfn = zone->compact_cached_migrate_pfn[sync]; - cc->free_pfn = zone->compact_cached_free_pfn; + cc->migrate_pfn = cc->zone->compact_cached_migrate_pfn[sync]; + cc->free_pfn = cc->zone->compact_cached_free_pfn; if (cc->free_pfn < start_pfn || cc->free_pfn >= end_pfn) { cc->free_pfn = pageblock_start_pfn(end_pfn - 1); - zone->compact_cached_free_pfn = cc->free_pfn; + cc->zone->compact_cached_free_pfn = cc->free_pfn; } if (cc->migrate_pfn < start_pfn || cc->migrate_pfn >= end_pfn) { cc->migrate_pfn = start_pfn; - zone->compact_cached_migrate_pfn[0] = cc->migrate_pfn; - zone->compact_cached_migrate_pfn[1] = cc->migrate_pfn; + cc->zone->compact_cached_migrate_pfn[0] = cc->migrate_pfn; + cc->zone->compact_cached_migrate_pfn[1] = cc->migrate_pfn; } - if (cc->migrate_pfn == start_pfn) + if (cc->migrate_pfn <= cc->zone->compact_init_migrate_pfn) cc->whole_zone = true; } - cc->last_migrated_pfn = 0; + last_migrated_pfn = 0; + + /* + * Migrate has separate cached PFNs for ASYNC and SYNC* migration on + * the basis that some migrations will fail in ASYNC mode. However, + * if the cached PFNs match and pageblocks are skipped due to having + * no isolation candidates, then the sync state does not matter. + * Until a pageblock with isolation candidates is found, keep the + * cached PFNs in sync to avoid revisiting the same blocks. + */ + update_cached = !sync && + cc->zone->compact_cached_migrate_pfn[0] == cc->zone->compact_cached_migrate_pfn[1]; trace_mm_compaction_begin(start_pfn, cc->migrate_pfn, cc->free_pfn, end_pfn, sync); migrate_prep_local(); - while ((ret = compact_finished(zone, cc)) == COMPACT_CONTINUE) { + while ((ret = compact_finished(cc)) == COMPACT_CONTINUE) { int err; + unsigned long start_pfn = cc->migrate_pfn; + + /* + * Avoid multiple rescans which can happen if a page cannot be + * isolated (dirty/writeback in async mode) or if the migrated + * pages are being allocated before the pageblock is cleared. + * The first rescan will capture the entire pageblock for + * migration. If it fails, it'll be marked skip and scanning + * will proceed as normal. + */ + cc->rescan = false; + if (pageblock_start_pfn(last_migrated_pfn) == + pageblock_start_pfn(start_pfn)) { + cc->rescan = true; + } - switch (isolate_migratepages(zone, cc)) { + switch (isolate_migratepages(cc->zone, cc)) { case ISOLATE_ABORT: ret = COMPACT_CONTENDED; putback_movable_pages(&cc->migratepages); cc->nr_migratepages = 0; + last_migrated_pfn = 0; goto out; case ISOLATE_NONE: + if (update_cached) { + cc->zone->compact_cached_migrate_pfn[1] = + cc->zone->compact_cached_migrate_pfn[0]; + } + /* * We haven't isolated and migrated anything, but * there might still be unflushed migrations from @@ -1608,6 +2166,8 @@ static enum compact_result compact_zone(struct zone *zone, struct compact_contro */ goto check_drain; case ISOLATE_SUCCESS: + update_cached = false; + last_migrated_pfn = start_pfn; ; } @@ -1639,8 +2199,7 @@ static enum compact_result compact_zone(struct zone *zone, struct compact_contro cc->migrate_pfn = block_end_pfn( cc->migrate_pfn - 1, cc->order); /* Draining pcplists is useless in this case */ - cc->last_migrated_pfn = 0; - + last_migrated_pfn = 0; } } @@ -1652,21 +2211,26 @@ check_drain: * compact_finished() can detect immediately if allocation * would succeed. */ - if (cc->order > 0 && cc->last_migrated_pfn) { + if (cc->order > 0 && last_migrated_pfn) { int cpu; unsigned long current_block_start = block_start_pfn(cc->migrate_pfn, cc->order); - if (cc->last_migrated_pfn < current_block_start) { + if (last_migrated_pfn < current_block_start) { cpu = get_cpu(); lru_add_drain_cpu(cpu); - drain_local_pages(zone); + drain_local_pages(cc->zone); put_cpu(); /* No more flushing until we migrate again */ - cc->last_migrated_pfn = 0; + last_migrated_pfn = 0; } } + /* Stop if a page has been captured */ + if (capc && capc->page) { + ret = COMPACT_SUCCESS; + break; + } } out: @@ -1685,8 +2249,8 @@ out: * Only go back, not forward. The cached pfn might have been * already reset to zone end in compact_finished() */ - if (free_pfn > zone->compact_cached_free_pfn) - zone->compact_cached_free_pfn = free_pfn; + if (free_pfn > cc->zone->compact_cached_free_pfn) + cc->zone->compact_cached_free_pfn = free_pfn; } count_compact_events(COMPACTMIGRATE_SCANNED, cc->total_migrate_scanned); @@ -1700,7 +2264,8 @@ out: static enum compact_result compact_zone_order(struct zone *zone, int order, gfp_t gfp_mask, enum compact_priority prio, - unsigned int alloc_flags, int classzone_idx) + unsigned int alloc_flags, int classzone_idx, + struct page **capture) { enum compact_result ret; struct compact_control cc = { @@ -1709,6 +2274,7 @@ static enum compact_result compact_zone_order(struct zone *zone, int order, .total_migrate_scanned = 0, .total_free_scanned = 0, .order = order, + .search_order = order, .gfp_mask = gfp_mask, .zone = zone, .mode = (prio == COMPACT_PRIO_ASYNC) ? @@ -1720,14 +2286,24 @@ static enum compact_result compact_zone_order(struct zone *zone, int order, .ignore_skip_hint = (prio == MIN_COMPACT_PRIORITY), .ignore_block_suitable = (prio == MIN_COMPACT_PRIORITY) }; + struct capture_control capc = { + .cc = &cc, + .page = NULL, + }; + + if (capture) + current->capture_control = &capc; INIT_LIST_HEAD(&cc.freepages); INIT_LIST_HEAD(&cc.migratepages); - ret = compact_zone(zone, &cc); + ret = compact_zone(&cc, &capc); VM_BUG_ON(!list_empty(&cc.freepages)); VM_BUG_ON(!list_empty(&cc.migratepages)); + *capture = capc.page; + current->capture_control = NULL; + return ret; } @@ -1745,7 +2321,7 @@ int sysctl_extfrag_threshold = 500; */ enum compact_result try_to_compact_pages(gfp_t gfp_mask, unsigned int order, unsigned int alloc_flags, const struct alloc_context *ac, - enum compact_priority prio) + enum compact_priority prio, struct page **capture) { int may_perform_io = gfp_mask & __GFP_IO; struct zoneref *z; @@ -1773,7 +2349,7 @@ enum compact_result try_to_compact_pages(gfp_t gfp_mask, unsigned int order, } status = compact_zone_order(zone, order, gfp_mask, prio, - alloc_flags, ac_classzone_idx(ac)); + alloc_flags, ac_classzone_idx(ac), capture); rc = max(status, rc); /* The allocation should succeed, stop compacting */ @@ -1841,7 +2417,7 @@ static void compact_node(int nid) INIT_LIST_HEAD(&cc.freepages); INIT_LIST_HEAD(&cc.migratepages); - compact_zone(zone, &cc); + compact_zone(&cc, NULL); VM_BUG_ON(!list_empty(&cc.freepages)); VM_BUG_ON(!list_empty(&cc.migratepages)); @@ -1876,14 +2452,6 @@ int sysctl_compaction_handler(struct ctl_table *table, int write, return 0; } -int sysctl_extfrag_handler(struct ctl_table *table, int write, - void __user *buffer, size_t *length, loff_t *ppos) -{ - proc_dointvec_minmax(table, write, buffer, length, ppos); - - return 0; -} - #if defined(CONFIG_SYSFS) && defined(CONFIG_NUMA) static ssize_t sysfs_compact_node(struct device *dev, struct device_attribute *attr, @@ -1948,6 +2516,7 @@ static void kcompactd_do_work(pg_data_t *pgdat) struct zone *zone; struct compact_control cc = { .order = pgdat->kcompactd_max_order, + .search_order = pgdat->kcompactd_max_order, .total_migrate_scanned = 0, .total_free_scanned = 0, .classzone_idx = pgdat->kcompactd_classzone_idx, @@ -1983,7 +2552,7 @@ static void kcompactd_do_work(pg_data_t *pgdat) if (kthread_should_stop()) return; - status = compact_zone(zone, &cc); + status = compact_zone(&cc, NULL); if (status == COMPACT_SUCCESS) { compaction_defer_reset(zone, cc.order, false); |