From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751352AbdBXLkz (ORCPT ); Fri, 24 Feb 2017 06:40:55 -0500 Received: from mga05.intel.com ([192.55.52.43]:23851 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751257AbdBXLkf (ORCPT ); Fri, 24 Feb 2017 06:40:35 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.35,200,1484035200"; d="scan'208";a="69710325" From: Aaron Lu To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Dave Hansen , Tim Chen , Andrew Morton , Ying Huang , Aaron Lu Subject: [PATCH 3/5] mm: use a dedicated workqueue for the free workers Date: Fri, 24 Feb 2017 19:40:34 +0800 Message-Id: <20170224114036.15621-4-aaron.lu@intel.com> X-Mailer: git-send-email 2.9.3 In-Reply-To: <20170224114036.15621-1-aaron.lu@intel.com> References: <20170224114036.15621-1-aaron.lu@intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Introduce a workqueue for all the free workers so that user can fine tune how many workers can be active through sysfs interface: max_active. More workers will normally lead to better performance, but too many can cause severe lock contention. Note that since the zone lock is global, the workqueue is also global for all processes, i.e. if we set 8 to max_active, we will have at most 8 workers active for all processes that are doing munmap()/exit()/etc. Signed-off-by: Aaron Lu --- mm/memory.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/mm/memory.c b/mm/memory.c index b98cd25075f0..eb8b17fc1b2b 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -254,6 +254,18 @@ static void tlb_flush_mmu_tlbonly(struct mmu_gather *tlb) __tlb_reset_range(tlb); } +static struct workqueue_struct *batch_free_wq; +static int __init batch_free_wq_init(void) +{ + batch_free_wq = alloc_workqueue("batch_free_wq", WQ_UNBOUND | WQ_SYSFS, 0); + if (!batch_free_wq) { + pr_warn("failed to create workqueue batch_free_wq\n"); + return -ENOMEM; + } + return 0; +} +subsys_initcall(batch_free_wq_init); + static void tlb_flush_mmu_free_batches(struct mmu_gather_batch *batch_start, int free_batch_page) { @@ -305,7 +317,7 @@ static void tlb_flush_mmu_free(struct mmu_gather *tlb) batch_free->batch_start = tlb->local.next; INIT_WORK(&batch_free->work, batch_free_work); list_add(&batch_free->list, &tlb->worker_list); - queue_work(system_unbound_wq, &batch_free->work); + queue_work(batch_free_wq, &batch_free->work); tlb->batch_count = 0; tlb->local.next = NULL; -- 2.9.3