diff options
Diffstat (limited to 'mm/page_alloc.c')
| -rw-r--r-- | mm/page_alloc.c | 162 |
1 files changed, 113 insertions, 49 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 2c25de46c58f..f9e450c6b6e4 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1832,9 +1832,9 @@ static inline struct page *__rmqueue_cma_fallback(struct zone *zone, * Note that start_page and end_pages are not aligned on a pageblock * boundary. If alignment is required, use move_freepages_block() */ -int move_freepages(struct zone *zone, +static int move_freepages(struct zone *zone, struct page *start_page, struct page *end_page, - int migratetype) + int migratetype, int *num_movable) { struct page *page; unsigned int order; @@ -1851,6 +1851,9 @@ int move_freepages(struct zone *zone, VM_BUG_ON(page_zone(start_page) != page_zone(end_page)); #endif + if (num_movable) + *num_movable = 0; + for (page = start_page; page <= end_page;) { if (!pfn_valid_within(page_to_pfn(page))) { page++; @@ -1861,6 +1864,15 @@ int move_freepages(struct zone *zone, VM_BUG_ON_PAGE(page_to_nid(page) != zone_to_nid(zone), page); if (!PageBuddy(page)) { + /* + * We assume that pages that could be isolated for + * migration are movable. But we don't actually try + * isolating, as that would be expensive. + */ + if (num_movable && + (PageLRU(page) || __PageMovable(page))) + (*num_movable)++; + page++; continue; } @@ -1876,7 +1888,7 @@ int move_freepages(struct zone *zone, } int move_freepages_block(struct zone *zone, struct page *page, - int migratetype) + int migratetype, int *num_movable) { unsigned long start_pfn, end_pfn; struct page *start_page, *end_page; @@ -1893,7 +1905,8 @@ int move_freepages_block(struct zone *zone, struct page *page, if (!zone_spans_pfn(zone, end_pfn)) return 0; - return move_freepages(zone, start_page, end_page, migratetype); + return move_freepages(zone, start_page, end_page, migratetype, + num_movable); } static void change_pageblock_range(struct page *pageblock_page, @@ -1943,28 +1956,79 @@ static bool can_steal_fallback(unsigned int order, int start_mt) /* * This function implements actual steal behaviour. If order is large enough, * we can steal whole pageblock. If not, we first move freepages in this - * pageblock and check whether half of pages are moved or not. If half of - * pages are moved, we can change migratetype of pageblock and permanently - * use it's pages as requested migratetype in the future. + * pageblock to our migratetype and determine how many already-allocated pages + * are there in the pageblock with a compatible migratetype. If at least half + * of pages are free or compatible, we can change migratetype of the pageblock + * itself, so pages freed in the future will be put on the correct free list. */ static void steal_suitable_fallback(struct zone *zone, struct page *page, - int start_type) + int start_type, bool whole_block) { unsigned int current_order = page_order(page); - int pages; + struct free_area *area; + int free_pages, movable_pages, alike_pages; + int old_block_type; + + old_block_type = get_pageblock_migratetype(page); + + /* + * This can happen due to races and we want to prevent broken + * highatomic accounting. + */ + if (is_migrate_highatomic(old_block_type)) + goto single_page; /* Take ownership for orders >= pageblock_order */ if (current_order >= pageblock_order) { change_pageblock_range(page, current_order, start_type); - return; + goto single_page; + } + + /* We are not allowed to try stealing from the whole block */ + if (!whole_block) + goto single_page; + + free_pages = move_freepages_block(zone, page, start_type, + &movable_pages); + /* + * Determine how many pages are compatible with our allocation. + * For movable allocation, it's the number of movable pages which + * we just obtained. For other types it's a bit more tricky. + */ + if (start_type == MIGRATE_MOVABLE) { + alike_pages = movable_pages; + } else { + /* + * If we are falling back a RECLAIMABLE or UNMOVABLE allocation + * to MOVABLE pageblock, consider all non-movable pages as + * compatible. If it's UNMOVABLE falling back to RECLAIMABLE or + * vice versa, be conservative since we can't distinguish the + * exact migratetype of non-movable pages. + */ + if (old_block_type == MIGRATE_MOVABLE) + alike_pages = pageblock_nr_pages + - (free_pages + movable_pages); + else + alike_pages = 0; } - pages = move_freepages_block(zone, page, start_type); + /* moving whole block can fail due to zone boundary conditions */ + if (!free_pages) + goto single_page; - /* Claim the whole block if over half of it is free */ - if (pages >= (1 << (pageblock_order-1)) || + /* + * If a sufficient number of pages in the block are either free or of + * comparable migratability as our allocation, claim the whole block. + */ + if (free_pages + alike_pages >= (1 << (pageblock_order-1)) || page_group_by_mobility_disabled) set_pageblock_migratetype(page, start_type); + + return; + +single_page: + area = &zone->free_area[current_order]; + list_move(&page->lru, &area->free_list[start_type]); } /* @@ -2034,7 +2098,7 @@ static void reserve_highatomic_pageblock(struct page *page, struct zone *zone, && !is_migrate_cma(mt)) { zone->nr_reserved_highatomic += pageblock_nr_pages; set_pageblock_migratetype(page, MIGRATE_HIGHATOMIC); - move_freepages_block(zone, page, MIGRATE_HIGHATOMIC); + move_freepages_block(zone, page, MIGRATE_HIGHATOMIC, NULL); } out_unlock: @@ -2111,7 +2175,8 @@ static bool unreserve_highatomic_pageblock(const struct alloc_context *ac, * may increase. */ set_pageblock_migratetype(page, ac->migratetype); - ret = move_freepages_block(zone, page, ac->migratetype); + ret = move_freepages_block(zone, page, ac->migratetype, + NULL); if (ret) { spin_unlock_irqrestore(&zone->lock, flags); return ret; @@ -2123,8 +2188,13 @@ static bool unreserve_highatomic_pageblock(const struct alloc_context *ac, return false; } -/* Remove an element from the buddy allocator from the fallback list */ -static inline struct page * +/* + * Try finding a free buddy page on the fallback list and put it on the free + * list of requested migratetype, possibly along with other pages from the same + * block, depending on fragmentation avoidance heuristics. Returns true if + * fallback was found so that __rmqueue_smallest() can grab it. + */ +static inline bool __rmqueue_fallback(struct zone *zone, unsigned int order, int start_migratetype) { struct free_area *area; @@ -2145,32 +2215,17 @@ __rmqueue_fallback(struct zone *zone, unsigned int order, int start_migratetype) page = list_first_entry(&area->free_list[fallback_mt], struct page, lru); - if (can_steal && !is_migrate_highatomic_page(page)) - steal_suitable_fallback(zone, page, start_migratetype); - - /* Remove the page from the freelists */ - area->nr_free--; - list_del(&page->lru); - rmv_page_order(page); - expand(zone, page, order, current_order, area, - start_migratetype); - /* - * The pcppage_migratetype may differ from pageblock's - * migratetype depending on the decisions in - * find_suitable_fallback(). This is OK as long as it does not - * differ for MIGRATE_CMA pageblocks. Those can be used as - * fallback only via special __rmqueue_cma_fallback() function - */ - set_pcppage_migratetype(page, start_migratetype); + steal_suitable_fallback(zone, page, start_migratetype, + can_steal); trace_mm_page_alloc_extfrag(page, order, current_order, start_migratetype, fallback_mt); - return page; + return true; } - return NULL; + return false; } /* @@ -2182,13 +2237,14 @@ static struct page *__rmqueue(struct zone *zone, unsigned int order, { struct page *page; +retry: page = __rmqueue_smallest(zone, order, migratetype); if (unlikely(!page)) { if (migratetype == MIGRATE_MOVABLE) page = __rmqueue_cma_fallback(zone, order); - if (!page) - page = __rmqueue_fallback(zone, order, migratetype); + if (!page && __rmqueue_fallback(zone, order, migratetype)) + goto retry; } trace_mm_page_alloc_zone_locked(page, order, migratetype); @@ -3227,14 +3283,15 @@ __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order, enum compact_priority prio, enum compact_result *compact_result) { struct page *page; + unsigned int noreclaim_flag; if (!order) return NULL; - current->flags |= PF_MEMALLOC; + noreclaim_flag = memalloc_noreclaim_save(); *compact_result = try_to_compact_pages(gfp_mask, order, alloc_flags, ac, prio); - current->flags &= ~PF_MEMALLOC; + memalloc_noreclaim_restore(noreclaim_flag); if (*compact_result <= COMPACT_INACTIVE) return NULL; @@ -3381,12 +3438,13 @@ __perform_reclaim(gfp_t gfp_mask, unsigned int order, { struct reclaim_state reclaim_state; int progress; + unsigned int noreclaim_flag; cond_resched(); /* We now go into synchronous reclaim */ cpuset_memory_pressure_bump(); - current->flags |= PF_MEMALLOC; + noreclaim_flag = memalloc_noreclaim_save(); lockdep_set_current_reclaim_state(gfp_mask); reclaim_state.reclaimed_slab = 0; current->reclaim_state = &reclaim_state; @@ -3396,7 +3454,7 @@ __perform_reclaim(gfp_t gfp_mask, unsigned int order, current->reclaim_state = NULL; lockdep_clear_current_reclaim_state(); - current->flags &= ~PF_MEMALLOC; + memalloc_noreclaim_restore(noreclaim_flag); cond_resched(); @@ -3609,6 +3667,7 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order, struct alloc_context *ac) { bool can_direct_reclaim = gfp_mask & __GFP_DIRECT_RECLAIM; + const bool costly_order = order > PAGE_ALLOC_COSTLY_ORDER; struct page *page = NULL; unsigned int alloc_flags; unsigned long did_some_progress; @@ -3676,12 +3735,17 @@ retry_cpuset: /* * For costly allocations, try direct compaction first, as it's likely - * that we have enough base pages and don't need to reclaim. Don't try - * that for allocations that are allowed to ignore watermarks, as the - * ALLOC_NO_WATERMARKS attempt didn't yet happen. + * that we have enough base pages and don't need to reclaim. For non- + * movable high-order allocations, do that as well, as compaction will + * try prevent permanent fragmentation by migrating from blocks of the + * same migratetype. + * Don't try this for allocations that are allowed to ignore + * watermarks, as the ALLOC_NO_WATERMARKS attempt didn't yet happen. */ - if (can_direct_reclaim && order > PAGE_ALLOC_COSTLY_ORDER && - !gfp_pfmemalloc_allowed(gfp_mask)) { + if (can_direct_reclaim && + (costly_order || + (order > 0 && ac->migratetype != MIGRATE_MOVABLE)) + && !gfp_pfmemalloc_allowed(gfp_mask)) { page = __alloc_pages_direct_compact(gfp_mask, order, alloc_flags, ac, INIT_COMPACT_PRIORITY, @@ -3693,7 +3757,7 @@ retry_cpuset: * Checks for costly allocations with __GFP_NORETRY, which * includes THP page fault allocations */ - if (gfp_mask & __GFP_NORETRY) { + if (costly_order && (gfp_mask & __GFP_NORETRY)) { /* * If compaction is deferred for high-order allocations, * it is because sync compaction recently failed. If @@ -3774,7 +3838,7 @@ retry: * Do not retry costly high order allocations unless they are * __GFP_REPEAT */ - if (order > PAGE_ALLOC_COSTLY_ORDER && !(gfp_mask & __GFP_REPEAT)) + if (costly_order && !(gfp_mask & __GFP_REPEAT)) goto nopage; if (should_reclaim_retry(gfp_mask, order, ac, alloc_flags, |