Date: Fri, 11 Jul 2014 10:17:41 -0500 (CDT)
From: Christoph Lameter <cl@gentwo.org>
To: Frederic Weisbecker <fweisbec@gmail.com>
cc: akpm@linux-foundation.org, Gilad Ben-Yossef <gilad@benyossef.com>,
        Thomas Gleixner <tglx@linutronix.de>, Tejun Heo <tj@kernel.org>,
        John Stultz <johnstul@us.ibm.com>, Mike Frysinger <vapier@gentoo.org>,
        Minchan Kim <minchan.kim@gmail.com>,
        Hakan Akkan <hakanakkan@gmail.com>,
        Max Krasnyansky <maxk@qualcomm.com>,
        "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org, hughd@google.com,
        viresh.kumar@linaro.org, hpa@zytor.com, mingo@kernel.org,
        peterz@infradead.org
Subject: Re: vmstat: On demand vmstat workers V8
In-Reply-To: <20140711135854.GD26045@localhost.localdomain>
Message-ID: <alpine.DEB.2.11.1407111016040.26485@gentwo.org>
References: <alpine.DEB.2.11.1407100903130.12483@gentwo.org> <20140711132032.GB26045@localhost.localdomain> <alpine.DEB.2.11.1407110855030.25432@gentwo.org> <20140711135854.GD26045@localhost.localdomain>
Content-Type: TEXT/PLAIN; charset=US-ASCII
Sender: linux-kernel-owner@vger.kernel.org

On Fri, 11 Jul 2014, Frederic Weisbecker wrote:

> > Converted what? We still need to keep a cpumask around that tells us which
> > processor have vmstat running and which do not.
> >
>
> Converted to cpumask_var_t.
>
> I mean we spent dozens emails on that...


Oh there is this outstanding fix, right.


Subject: on demand vmstat: Do not open code alloc_cpumask_var

Signed-off-by: Christoph Lameter <cl@linux.com>

Index: linux/mm/vmstat.c
===================================================================
--- linux.orig/mm/vmstat.c	2014-07-11 10:15:55.356856916 -0500
+++ linux/mm/vmstat.c	2014-07-11 10:15:55.352856994 -0500
@@ -1244,7 +1244,7 @@
 #ifdef CONFIG_SMP
 static DEFINE_PER_CPU(struct delayed_work, vmstat_work);
 int sysctl_stat_interval __read_mostly = HZ;
-struct cpumask *cpu_stat_off;
+cpumask_var_t cpu_stat_off;

 static void vmstat_update(struct work_struct *w)
 {
@@ -1338,7 +1338,8 @@
 		INIT_DEFERRABLE_WORK(per_cpu_ptr(&vmstat_work, cpu),
 			vmstat_update);

-	cpu_stat_off = kmalloc(cpumask_size(), GFP_KERNEL);
+	if (!alloc_cpumask_var(&cpu_stat_off, GFP_KERNEL))
+		BUG();
 	cpumask_copy(cpu_stat_off, cpu_online_mask);

 	schedule_delayed_work(&shepherd,
--
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