diff options
| -rw-r--r-- | mm/swap.c | 104 |
1 files changed, 74 insertions, 30 deletions
diff --git a/mm/swap.c b/mm/swap.c index d93fa1e9ec7c..d034b2128d2b 100644 --- a/mm/swap.c +++ b/mm/swap.c @@ -32,6 +32,10 @@ /* How many pages do we try to swap or page in/out together? */ int page_cluster; +static DEFINE_PER_CPU(struct pagevec, lru_add_pvecs) = { 0, }; +static DEFINE_PER_CPU(struct pagevec, lru_add_active_pvecs) = { 0, }; +static DEFINE_PER_CPU(struct pagevec, lru_rotate_pvecs) = { 0, }; + /* * This path almost never happens for VM activity - pages are normally * freed via pagevecs. But it gets used by networking. @@ -92,23 +96,47 @@ void put_pages_list(struct list_head *pages) EXPORT_SYMBOL(put_pages_list); /* + * pagevec_move_tail() must be called with IRQ disabled. + * Otherwise this may cause nasty races. + */ +static void pagevec_move_tail(struct pagevec *pvec) +{ + int i; + int pgmoved = 0; + struct zone *zone = NULL; + + for (i = 0; i < pagevec_count(pvec); i++) { + struct page *page = pvec->pages[i]; + struct zone *pagezone = page_zone(page); + + if (pagezone != zone) { + if (zone) + spin_unlock(&zone->lru_lock); + zone = pagezone; + spin_lock(&zone->lru_lock); + } + if (PageLRU(page) && !PageActive(page)) { + list_move_tail(&page->lru, &zone->inactive_list); + pgmoved++; + } + } + if (zone) + spin_unlock(&zone->lru_lock); + __count_vm_events(PGROTATED, pgmoved); + release_pages(pvec->pages, pvec->nr, pvec->cold); + pagevec_reinit(pvec); +} + +/* * Writeback is about to end against a page which has been marked for immediate * reclaim. If it still appears to be reclaimable, move it to the tail of the - * inactive list. The page still has PageWriteback set, which will pin it. - * - * We don't expect many pages to come through here, so don't bother batching - * things up. - * - * To avoid placing the page at the tail of the LRU while PG_writeback is still - * set, this function will clear PG_writeback before performing the page - * motion. Do that inside the lru lock because once PG_writeback is cleared - * we may not touch the page. + * inactive list. * * Returns zero if it cleared PG_writeback. */ int rotate_reclaimable_page(struct page *page) { - struct zone *zone; + struct pagevec *pvec; unsigned long flags; if (PageLocked(page)) @@ -120,15 +148,16 @@ int rotate_reclaimable_page(struct page *page) if (!PageLRU(page)) return 1; - zone = page_zone(page); - spin_lock_irqsave(&zone->lru_lock, flags); - if (PageLRU(page) && !PageActive(page)) { - list_move_tail(&page->lru, &zone->inactive_list); - __count_vm_event(PGROTATED); - } + page_cache_get(page); + local_irq_save(flags); + pvec = &__get_cpu_var(lru_rotate_pvecs); + if (!pagevec_add(pvec, page)) + pagevec_move_tail(pvec); + local_irq_restore(flags); + if (!test_clear_page_writeback(page)) BUG(); - spin_unlock_irqrestore(&zone->lru_lock, flags); + return 0; } @@ -172,9 +201,6 @@ EXPORT_SYMBOL(mark_page_accessed); * lru_cache_add: add a page to the page lists * @page: the page to add */ -static DEFINE_PER_CPU(struct pagevec, lru_add_pvecs) = { 0, }; -static DEFINE_PER_CPU(struct pagevec, lru_add_active_pvecs) = { 0, }; - void fastcall lru_cache_add(struct page *page) { struct pagevec *pvec = &get_cpu_var(lru_add_pvecs); @@ -195,21 +221,37 @@ void fastcall lru_cache_add_active(struct page *page) put_cpu_var(lru_add_active_pvecs); } -static void __lru_add_drain(int cpu) +/* + * Drain pages out of the cpu's pagevecs. + * Either "cpu" is the current CPU, and preemption has already been + * disabled; or "cpu" is being hot-unplugged, and is already dead. + */ +static void drain_cpu_pagevecs(int cpu) { - struct pagevec *pvec = &per_cpu(lru_add_pvecs, cpu); + struct pagevec *pvec; - /* CPU is dead, so no locking needed. */ + pvec = &per_cpu(lru_add_pvecs, cpu); if (pagevec_count(pvec)) __pagevec_lru_add(pvec); + pvec = &per_cpu(lru_add_active_pvecs, cpu); if (pagevec_count(pvec)) __pagevec_lru_add_active(pvec); + + pvec = &per_cpu(lru_rotate_pvecs, cpu); + if (pagevec_count(pvec)) { + unsigned long flags; + + /* No harm done if a racing interrupt already did this */ + local_irq_save(flags); + pagevec_move_tail(pvec); + local_irq_restore(flags); + } } void lru_add_drain(void) { - __lru_add_drain(get_cpu()); + drain_cpu_pagevecs(get_cpu()); put_cpu(); } @@ -256,6 +298,7 @@ void release_pages(struct page **pages, int nr, int cold) int i; struct pagevec pages_to_free; struct zone *zone = NULL; + unsigned long uninitialized_var(flags); pagevec_init(&pages_to_free, cold); for (i = 0; i < nr; i++) { @@ -263,7 +306,7 @@ void release_pages(struct page **pages, int nr, int cold) if (unlikely(PageCompound(page))) { if (zone) { - spin_unlock_irq(&zone->lru_lock); + spin_unlock_irqrestore(&zone->lru_lock, flags); zone = NULL; } put_compound_page(page); @@ -277,9 +320,10 @@ void release_pages(struct page **pages, int nr, int cold) struct zone *pagezone = page_zone(page); if (pagezone != zone) { if (zone) - spin_unlock_irq(&zone->lru_lock); + spin_unlock_irqrestore(&zone->lru_lock, + flags); zone = pagezone; - spin_lock_irq(&zone->lru_lock); + spin_lock_irqsave(&zone->lru_lock, flags); } VM_BUG_ON(!PageLRU(page)); __ClearPageLRU(page); @@ -288,7 +332,7 @@ void release_pages(struct page **pages, int nr, int cold) if (!pagevec_add(&pages_to_free, page)) { if (zone) { - spin_unlock_irq(&zone->lru_lock); + spin_unlock_irqrestore(&zone->lru_lock, flags); zone = NULL; } __pagevec_free(&pages_to_free); @@ -296,7 +340,7 @@ void release_pages(struct page **pages, int nr, int cold) } } if (zone) - spin_unlock_irq(&zone->lru_lock); + spin_unlock_irqrestore(&zone->lru_lock, flags); pagevec_free(&pages_to_free); } @@ -489,7 +533,7 @@ static int cpu_swap_callback(struct notifier_block *nfb, if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) { atomic_add(*committed, &vm_committed_space); *committed = 0; - __lru_add_drain((long)hcpu); + drain_cpu_pagevecs((long)hcpu); } return NOTIFY_OK; } |