From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755290AbbJ1Clw (ORCPT ); Tue, 27 Oct 2015 22:41:52 -0400 Received: from resqmta-ch2-02v.sys.comcast.net ([69.252.207.34]:37790 "EHLO resqmta-ch2-02v.sys.comcast.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755244AbbJ1Clg (ORCPT ); Tue, 27 Oct 2015 22:41:36 -0400 Message-Id: <20151028024131.719968999@linux.com> Date: Tue, 27 Oct 2015 21:41:17 -0500 From: Christoph Lameter To: akpm@linux-foundation.org Cc: Michal Hocko , Tejun Heo Cc: Tetsuo Handa , linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, torvalds@linux-foundation.org Cc: hannes@cmpxchg.org, mgorman@suse.de Subject: [patch 3/3] vmstat: Create our own workqueue References: <20151028024114.370693277@linux.com> Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline; filename=vmstat_add_workqueue Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Seems that vmstat needs its own workqueue now since the general workqueue mechanism has been *enhanced* which means that the vmstat_updates cannot run reliably but are being blocked by work requests doing memory allocation. Which causes vmstat to be unable to keep the counters up to date. Bad. Fix this by creating our own workqueue. Signed-off-by: Christoph Lameter Index: linux/mm/vmstat.c =================================================================== --- linux.orig/mm/vmstat.c +++ linux/mm/vmstat.c @@ -1359,6 +1359,8 @@ static const struct file_operations proc #endif /* CONFIG_PROC_FS */ #ifdef CONFIG_SMP +static struct workqueue_struct *vmstat_wq; + static DEFINE_PER_CPU(struct delayed_work, vmstat_work); int sysctl_stat_interval __read_mostly = HZ; static cpumask_var_t cpu_stat_off; @@ -1371,7 +1373,7 @@ static void vmstat_update(struct work_st * to occur in the future. Keep on running the * update worker thread. */ - schedule_delayed_work_on(smp_processor_id(), + queue_delayed_work_on(smp_processor_id(), vmstat_wq, this_cpu_ptr(&vmstat_work), round_jiffies_relative(sysctl_stat_interval)); } else { @@ -1454,7 +1456,7 @@ static void vmstat_shepherd(struct work_ if (need_update(cpu) && cpumask_test_and_clear_cpu(cpu, cpu_stat_off)) - schedule_delayed_work_on(cpu, + queue_delayed_work_on(cpu, vmstat_wq, &per_cpu(vmstat_work, cpu), 0); put_online_cpus(); @@ -1543,6 +1545,10 @@ static int __init setup_vmstat(void) start_shepherd_timer(); cpu_notifier_register_done(); + vmstat_wq = alloc_workqueue("vmstat", + WQ_FREEZABLE| + WQ_SYSFS| + WQ_MEM_RECLAIM, 0); #endif #ifdef CONFIG_PROC_FS proc_create("buddyinfo", S_IRUGO, NULL, &fragmentation_file_operations);