From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753192Ab2BTRYI (ORCPT ); Mon, 20 Feb 2012 12:24:08 -0500 Received: from mail-bk0-f46.google.com ([209.85.214.46]:43752 "EHLO mail-bk0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753078Ab2BTRYC (ORCPT ); Mon, 20 Feb 2012 12:24:02 -0500 Authentication-Results: mr.google.com; spf=pass (google.com: domain of koct9i@gmail.com designates 10.205.124.15 as permitted sender) smtp.mail=koct9i@gmail.com; dkim=pass header.i=koct9i@gmail.com Subject: [PATCH v2 22/22] mm: split zone->lru_lock To: linux-mm@kvack.org, Andrew Morton , linux-kernel@vger.kernel.org From: Konstantin Khlebnikov Cc: Hugh Dickins , KAMEZAWA Hiroyuki Date: Mon, 20 Feb 2012 21:23:57 +0400 Message-ID: <20120220172357.22196.67636.stgit@zurg> In-Reply-To: <20120220171138.22196.65847.stgit@zurg> References: <20120220171138.22196.65847.stgit@zurg> User-Agent: StGit/0.15 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Looks like all ready for splitting zone->lru_lock into per-lruvec pieces. lruvec locking loop protected with rcu. Memory controller already releases its lru-vectors via rcu, lru-vectors embedded into zones never released. Signed-off-by: Konstantin Khlebnikov --- include/linux/mmzone.h | 2 - mm/compaction.c | 2 - mm/internal.h | 100 ++++++++++++++++++++++++++++++------------------ mm/memcontrol.c | 1 mm/page_alloc.c | 2 - mm/swap.c | 2 - 6 files changed, 68 insertions(+), 41 deletions(-) diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 9fd82b1..56995db 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -301,6 +301,7 @@ struct lruvec { struct pglist_data *node; struct zone *zone; #endif + spinlock_t lru_lock; struct list_head pages_lru[NR_LRU_LISTS]; unsigned long pages_count[NR_LRU_LISTS]; @@ -378,7 +379,6 @@ struct zone { ZONE_PADDING(_pad1_) /* Fields commonly accessed by the page reclaim scanner */ - spinlock_t lru_lock; struct lruvec lruvec; unsigned long pages_scanned; /* since last reclaim */ diff --git a/mm/compaction.c b/mm/compaction.c index 1e89165..3fbb958 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -306,7 +306,7 @@ static isolate_migrate_t isolate_migratepages(struct zone *zone, lruvec = NULL; } if (need_resched() || - (lruvec && spin_is_contended(&zone->lru_lock))) { + (lruvec && spin_is_contended(&lruvec->lru_lock))) { if (lruvec) unlock_lruvec_irq(lruvec); lruvec = NULL; diff --git a/mm/internal.h b/mm/internal.h index a1a3206..110d653 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -15,76 +15,98 @@ static inline void lock_lruvec(struct lruvec *lruvec, unsigned long *flags) { - spin_lock_irqsave(&lruvec_zone(lruvec)->lru_lock, *flags); + spin_lock_irqsave(&lruvec->lru_lock, *flags); } static inline void lock_lruvec_irq(struct lruvec *lruvec) { - spin_lock_irq(&lruvec_zone(lruvec)->lru_lock); + spin_lock_irq(&lruvec->lru_lock); } static inline void unlock_lruvec(struct lruvec *lruvec, unsigned long *flags) { - spin_unlock_irqrestore(&lruvec_zone(lruvec)->lru_lock, *flags); + spin_unlock_irqrestore(&lruvec->lru_lock, *flags); } static inline void unlock_lruvec_irq(struct lruvec *lruvec) { - spin_unlock_irq(&lruvec_zone(lruvec)->lru_lock); + spin_unlock_irq(&lruvec->lru_lock); } static inline void wait_lruvec_unlock(struct lruvec *lruvec) { - spin_unlock_wait(&lruvec_zone(lruvec)->lru_lock); + spin_unlock_wait(&lruvec->lru_lock); } #ifdef CONFIG_CGROUP_MEM_RES_CTLR /* Dynamic page to lruvec mapping */ +/* protected with rcu, interrupts disabled, locked_lruvec != NULL */ +static inline struct lruvec *__catch_page_lruvec(struct lruvec *locked_lruvec, + struct page *page) +{ + struct lruvec *lruvec; + + do { + lruvec = page_lruvec(page); + if (likely(lruvec == locked_lruvec)) + return lruvec; + spin_unlock(&locked_lruvec->lru_lock); + spin_lock(&lruvec->lru_lock); + locked_lruvec = lruvec; + } while (1); +} + static inline struct lruvec *lock_page_lruvec(struct page *page, unsigned long *flags) { - struct zone *zone = page_zone(page); + struct lruvec *lruvec; - spin_lock_irqsave(&zone->lru_lock, *flags); - return page_lruvec(page); + rcu_read_lock(); + lruvec = page_lruvec(page); + lock_lruvec(lruvec, flags); + lruvec = __catch_page_lruvec(lruvec, page); + rcu_read_unlock(); + return lruvec; } static inline struct lruvec *lock_page_lruvec_irq(struct page *page) { - struct zone *zone = page_zone(page); + struct lruvec *lruvec; - spin_lock_irq(&zone->lru_lock); - return page_lruvec(page); + rcu_read_lock(); + lruvec = page_lruvec(page); + lock_lruvec_irq(lruvec); + lruvec = __catch_page_lruvec(lruvec, page); + rcu_read_unlock(); + return lruvec; } static inline struct lruvec *relock_page_lruvec(struct lruvec *lruvec, struct page *page, unsigned long *flags) { - struct zone *zone = page_zone(page); - - if (!lruvec || zone != lruvec_zone(lruvec)) { - if (lruvec) - unlock_lruvec(lruvec, flags); - lruvec = lock_page_lruvec(page, flags); + rcu_read_lock(); + if (!lruvec) { + lruvec = page_lruvec(page); + lock_lruvec(lruvec, flags); } - + lruvec = __catch_page_lruvec(lruvec, page); + rcu_read_unlock(); return lruvec; } static inline struct lruvec *relock_page_lruvec_irq(struct lruvec *lruvec, struct page *page) { - struct zone *zone = page_zone(page); - - if (!lruvec || zone != lruvec_zone(lruvec)) { - if (lruvec) - unlock_lruvec_irq(lruvec); - lruvec = lock_page_lruvec_irq(page); + rcu_read_lock(); + if (!lruvec) { + lruvec = page_lruvec(page); + lock_lruvec_irq(lruvec); } - + lruvec = __catch_page_lruvec(lruvec, page); + rcu_read_unlock(); return lruvec; } @@ -92,8 +114,10 @@ static inline struct lruvec *relock_page_lruvec_irq(struct lruvec *lruvec, static inline struct lruvec *__relock_page_lruvec(struct lruvec *lruvec, struct page *page) { - /* Currenyly only one lruvec per-zone */ - return page_lruvec(page); + rcu_read_lock(); + lruvec = __catch_page_lruvec(lruvec, page); + rcu_read_unlock(); + return lruvec; } /* @@ -104,22 +128,24 @@ static inline struct lruvec *__relock_page_lruvec(struct lruvec *lruvec, */ static inline bool catch_page_lruvec(struct lruvec **lruvec, struct page *page) { - struct zone *zone; bool ret = false; + rcu_read_lock(); + /* + * If we see there PageLRU(), it means page has valid lruvec link. + * We need protect whole operation with single rcu-interval, otherwise + * lruvec which hold this LRU sign can run out before we secure it. + */ if (PageLRU(page)) { if (!*lruvec) { - zone = page_zone(page); - spin_lock_irq(&zone->lru_lock); - } else - zone = lruvec_zone(*lruvec); - - if (PageLRU(page)) { *lruvec = page_lruvec(page); + lock_lruvec_irq(*lruvec); + } + *lruvec = __catch_page_lruvec(*lruvec, page); + if (PageLRU(page)) ret = true; - } else - *lruvec = &zone->lruvec; } + rcu_read_unlock(); return ret; } @@ -127,7 +153,7 @@ static inline bool catch_page_lruvec(struct lruvec **lruvec, struct page *page) /* Wait for lruvec unlock before locking other lruvec for the same page */ static inline void __wait_lruvec_unlock(struct lruvec *lruvec) { - /* Currently only one lruvec per-zone */ + wait_lruvec_unlock(lruvec); } #else /* CONFIG_CGROUP_MEM_RES_CTLR */ diff --git a/mm/memcontrol.c b/mm/memcontrol.c index eb024c1..d0ca9d0 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -4648,6 +4648,7 @@ static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node) INIT_LIST_HEAD(&mz->lruvec.pages_lru[lru]); mz->lruvec.pages_count[lru] = 0; } + spin_lock_init(&mz->lruvec.lru_lock); mz->lruvec.node = NODE_DATA(node); mz->lruvec.zone = &NODE_DATA(node)->node_zones[zone]; mz->usage_in_excess = 0; diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 72263e4..c258024 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -4357,7 +4357,7 @@ static void __paginginit free_area_init_core(struct pglist_data *pgdat, #endif zone->name = zone_names[j]; spin_lock_init(&zone->lock); - spin_lock_init(&zone->lru_lock); + spin_lock_init(&zone->lruvec.lru_lock); zone_seqlock_init(zone); zone->zone_pgdat = pgdat; diff --git a/mm/swap.c b/mm/swap.c index 9e81df3..43866d7 100644 --- a/mm/swap.c +++ b/mm/swap.c @@ -694,7 +694,7 @@ void lru_add_page_tail(struct lruvec *lruvec, VM_BUG_ON(!PageHead(page)); VM_BUG_ON(PageCompound(page_tail)); VM_BUG_ON(PageLRU(page_tail)); - VM_BUG_ON(NR_CPUS != 1 && !spin_is_locked(&lruvec_zone(lruvec)->lru_lock)); + VM_BUG_ON(NR_CPUS != 1 && !spin_is_locked(&lruvec->lru_lock)); SetPageLRU(page_tail);