diff options
| -rw-r--r-- | include/linux/compaction.h | 4 | ||||
| -rw-r--r-- | include/linux/mm.h | 1 | ||||
| -rw-r--r-- | mm/compaction.c | 90 | ||||
| -rw-r--r-- | mm/internal.h | 1 | ||||
| -rw-r--r-- | mm/page_alloc.c | 63 |
5 files changed, 130 insertions, 29 deletions
diff --git a/include/linux/compaction.h b/include/linux/compaction.h index ef658147e4e8..0e38a1deeb23 100644 --- a/include/linux/compaction.h +++ b/include/linux/compaction.h @@ -22,7 +22,7 @@ extern int sysctl_extfrag_handler(struct ctl_table *table, int write, extern int fragmentation_index(struct zone *zone, unsigned int order); extern unsigned long try_to_compact_pages(struct zonelist *zonelist, int order, gfp_t gfp_mask, nodemask_t *mask, - bool sync, bool *contended); + bool sync, bool *contended, struct page **page); extern int compact_pgdat(pg_data_t *pgdat, int order); extern unsigned long compaction_suitable(struct zone *zone, int order); @@ -64,7 +64,7 @@ static inline bool compaction_deferred(struct zone *zone, int order) #else static inline 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) { return COMPACT_CONTINUE; } diff --git a/include/linux/mm.h b/include/linux/mm.h index 0514fe9d3c84..5ddb11b2b4bb 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -442,6 +442,7 @@ void put_pages_list(struct list_head *pages); void split_page(struct page *page, unsigned int order); int split_free_page(struct page *page); +int capture_free_page(struct page *page, int alloc_order, int migratetype); /* * Compound pages have a destructor function. Provide a diff --git a/mm/compaction.c b/mm/compaction.c index 7168edc7592c..0fbc6b73a522 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])) - return COMPACT_PARTIAL; - - /* Job done if allocation would set block type */ - if (order >= pageblock_order && zone->free_area[order].nr_free) + 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 (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); diff --git a/mm/internal.h b/mm/internal.h index b8c91b342e24..e549a7fbc296 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -131,6 +131,7 @@ struct compact_control { int migratetype; /* MOVABLE, RECLAIMABLE etc */ struct zone *zone; bool *contended; /* True if a lock was contended */ + struct page **page; /* Page captured of requested size */ }; unsigned long diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 5e92698e5395..cfd565dbe124 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1380,16 +1380,11 @@ void split_page(struct page *page, unsigned int order) } /* - * Similar to split_page except the page is already free. As this is only - * being used for migration, the migratetype of the block also changes. - * As this is called with interrupts disabled, the caller is responsible - * for calling arch_alloc_page() and kernel_map_page() after interrupts - * are enabled. - * - * Note: this is probably too low level an operation for use in drivers. - * Please consult with lkml before using this in your driver. + * Similar to the split_page family of functions except that the page + * required at the given order and being isolated now to prevent races + * with parallel allocators */ -int split_free_page(struct page *page) +int capture_free_page(struct page *page, int alloc_order, int migratetype) { unsigned int order; unsigned long watermark; @@ -1411,10 +1406,11 @@ int split_free_page(struct page *page) rmv_page_order(page); __mod_zone_page_state(zone, NR_FREE_PAGES, -(1UL << order)); - /* Split into individual pages */ - set_page_refcounted(page); - split_page(page, order); + if (alloc_order != order) + expand(zone, page, alloc_order, order, + &zone->free_area[order], migratetype); + /* Set the pageblock if the captured page is at least a pageblock */ if (order >= pageblock_order - 1) { struct page *endpage = page + (1 << order) - 1; for (; page < endpage; page += pageblock_nr_pages) { @@ -1425,7 +1421,35 @@ int split_free_page(struct page *page) } } - return 1 << order; + return 1UL << order; +} + +/* + * Similar to split_page except the page is already free. As this is only + * being used for migration, the migratetype of the block also changes. + * As this is called with interrupts disabled, the caller is responsible + * for calling arch_alloc_page() and kernel_map_page() after interrupts + * are enabled. + * + * Note: this is probably too low level an operation for use in drivers. + * Please consult with lkml before using this in your driver. + */ +int split_free_page(struct page *page) +{ + unsigned int order; + int nr_pages; + + BUG_ON(!PageBuddy(page)); + order = page_order(page); + + nr_pages = capture_free_page(page, order, 0); + if (!nr_pages) + return 0; + + /* Split into individual pages */ + set_page_refcounted(page); + split_page(page, order); + return nr_pages; } /* @@ -2105,7 +2129,7 @@ __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order, bool *contended_compaction, bool *deferred_compaction, unsigned long *did_some_progress) { - struct page *page; + struct page *page = NULL; if (!order) return NULL; @@ -2118,10 +2142,16 @@ __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order, current->flags |= PF_MEMALLOC; *did_some_progress = try_to_compact_pages(zonelist, order, gfp_mask, nodemask, sync_migration, - contended_compaction); + contended_compaction, &page); current->flags &= ~PF_MEMALLOC; - if (*did_some_progress != COMPACT_SKIPPED) { + /* If compaction captured a page, prep and use it */ + if (page) { + prep_new_page(page, order, gfp_mask); + goto got_page; + } + + if (*did_some_progress != COMPACT_SKIPPED) { /* Page migration frees to the PCP lists but we want merging */ drain_pages(get_cpu()); put_cpu(); @@ -2131,6 +2161,7 @@ __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order, alloc_flags & ~ALLOC_NO_WATERMARKS, preferred_zone, migratetype); if (page) { +got_page: preferred_zone->compact_considered = 0; preferred_zone->compact_defer_shift = 0; if (order >= preferred_zone->compact_order_failed) |