Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760200Ab3HNU3Z (ORCPT ); Wed, 14 Aug 2013 16:29:25 -0400 Received: from usmamail.tilera.com ([12.216.194.151]:65528 "EHLO USMAMAIL.TILERA.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758543Ab3HNU3Y (ORCPT ); Wed, 14 Aug 2013 16:29:24 -0400 Message-ID: <201308142029.r7EKTMRw023404@farm-0002.internal.tilera.com> From: Chris Metcalf Date: Wed, 14 Aug 2013 16:22:18 -0400 In-Reply-To: <20130814200748.GI28628@htj.dyndns.org> Subject: [PATCH v8] mm: make lru_add_drain_all() selective To: Andrew Morton CC: Tejun Heo , , , Thomas Gleixner , Frederic Weisbecker , Cody P Schafer MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3846 Lines: 125 This change makes lru_add_drain_all() only selectively interrupt the cpus that have per-cpu free pages that can be drained. This is important in nohz mode where calling mlockall(), for example, otherwise will interrupt every core unnecessarily. Signed-off-by: Chris Metcalf Reviewed-by: Tejun Heo --- v8: Here's an actual git patch after Tejun's review. Pull everything inline into lru_add_drain_all(), and use a mutex plus build-time allocated work_structs to avoid allocation. v7: try a version with callbacks instead of cpu masks. Either this or v6 seem like reasonable solutions. v6: add Tejun's Acked-by, and add missing get/put_cpu_online to lru_add_drain_all(). v5: provide validity checking on the cpumask for schedule_on_cpu_mask. By providing an all-or-nothing EINVAL check, we impose the requirement that the calling code actually know clearly what it's trying to do. (Note: no change to the mm/swap.c commit) v4: don't lose possible -ENOMEM in schedule_on_each_cpu() (Note: no change to the mm/swap.c commit) v3: split commit into two, one for workqueue and one for mm, though both should probably be taken through -mm. include/linux/swap.h | 2 +- mm/swap.c | 44 +++++++++++++++++++++++++++++++++++++++----- 2 files changed, 40 insertions(+), 6 deletions(-) diff --git a/include/linux/swap.h b/include/linux/swap.h index d95cde5..acea8e0 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -247,7 +247,7 @@ extern void activate_page(struct page *); extern void mark_page_accessed(struct page *); extern void lru_add_drain(void); extern void lru_add_drain_cpu(int cpu); -extern int lru_add_drain_all(void); +extern void lru_add_drain_all(void); extern void rotate_reclaimable_page(struct page *page); extern void deactivate_page(struct page *page); extern void swap_setup(void); diff --git a/mm/swap.c b/mm/swap.c index 4a1d0d2..8d19543 100644 --- a/mm/swap.c +++ b/mm/swap.c @@ -405,6 +405,11 @@ static void activate_page_drain(int cpu) pagevec_lru_move_fn(pvec, __activate_page, NULL); } +static bool need_activate_page_drain(int cpu) +{ + return pagevec_count(&per_cpu(activate_page_pvecs, cpu)) != 0; +} + void activate_page(struct page *page) { if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) { @@ -422,6 +427,11 @@ static inline void activate_page_drain(int cpu) { } +static bool need_activate_page_drain(int cpu) +{ + return false; +} + void activate_page(struct page *page) { struct zone *zone = page_zone(page); @@ -678,12 +688,36 @@ static void lru_add_drain_per_cpu(struct work_struct *dummy) lru_add_drain(); } -/* - * Returns 0 for success - */ -int lru_add_drain_all(void) +static DEFINE_PER_CPU(struct work_struct, lru_add_drain_work); + +void lru_add_drain_all(void) { - return schedule_on_each_cpu(lru_add_drain_per_cpu); + static DEFINE_MUTEX(lock); + static struct cpumask has_work; + int cpu; + + mutex_lock(&lock); + get_online_cpus(); + cpumask_clear(&has_work); + + for_each_online_cpu(cpu) { + struct work_struct *work = &per_cpu(lru_add_drain_work, cpu); + + if (pagevec_count(&per_cpu(lru_add_pvec, cpu)) || + pagevec_count(&per_cpu(lru_rotate_pvecs, cpu)) || + pagevec_count(&per_cpu(lru_deactivate_pvecs, cpu)) || + need_activate_page_drain(cpu)) { + INIT_WORK(work, lru_add_drain_per_cpu); + schedule_work_on(cpu, work); + cpumask_set_cpu(cpu, &has_work); + } + } + + for_each_cpu(cpu, &has_work) + flush_work(&per_cpu(lru_add_drain_work, cpu)); + + put_online_cpus(); + mutex_unlock(&lock); } /* -- 1.8.3.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/