From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qg0-f51.google.com (mail-qg0-f51.google.com [209.85.192.51]) by kanga.kvack.org (Postfix) with ESMTP id B04276B0039 for ; Thu, 29 May 2014 12:40:24 -0400 (EDT) Received: by mail-qg0-f51.google.com with SMTP id q107so1774557qgd.10 for ; Thu, 29 May 2014 09:40:24 -0700 (PDT) Received: from e39.co.us.ibm.com (e39.co.us.ibm.com. [32.97.110.160]) by mx.google.com with ESMTPS id e67si2391341yhm.158.2014.05.29.09.40.23 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Thu, 29 May 2014 09:40:24 -0700 (PDT) Received: from /spool/local by e39.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 29 May 2014 10:40:23 -0600 Received: from b03cxnp08027.gho.boulder.ibm.com (b03cxnp08027.gho.boulder.ibm.com [9.17.130.19]) by d03dlp01.boulder.ibm.com (Postfix) with ESMTP id 22B00C40002 for ; Thu, 29 May 2014 10:40:20 -0600 (MDT) Received: from d03av06.boulder.ibm.com (d03av06.boulder.ibm.com [9.17.195.245]) by b03cxnp08027.gho.boulder.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id s4TGdOoF5046564 for ; Thu, 29 May 2014 18:39:24 +0200 Received: from d03av06.boulder.ibm.com (loopback [127.0.0.1]) by d03av06.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id s4TGiH9o016865 for ; Thu, 29 May 2014 10:44:18 -0600 Date: Thu, 29 May 2014 09:40:18 -0700 From: "Paul E. McKenney" Subject: Re: vmstat: On demand vmstat workers V5 Message-ID: <20140529164018.GM22231@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <20140528152107.GB6507@localhost.localdomain> <20140529003609.GG6507@localhost.localdomain> <20140529142602.GA20258@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: Christoph Lameter Cc: Frederic Weisbecker , Andrew Morton , Gilad Ben-Yossef , Thomas Gleixner , Tejun Heo , John Stultz , Mike Frysinger , Minchan Kim , Hakan Akkan , Max Krasnyansky , 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 On Thu, May 29, 2014 at 11:24:15AM -0500, Christoph Lameter wrote: > On Thu, 29 May 2014, Frederic Weisbecker wrote: > > > > Well yes and I am tying directly into that scheme there in cpu.c to > > > display the active vmstat threads in sysfs. so its the same. > > > > I don't think so. Or is there something in vmstat that cpumask_var_t > > definition depends upon? > > This patch definitely ties the vmstat cpumask into the scheme in cpu.c > > > > I would like to have some way to display the activities on cpus in /sysfs > > > like I have done here with the active vmstat workers. > > > > > > What I think we need is display cpumasks for > > > > > > 1. Cpus where the tick is currently off > > > 2. Cpus that have dynticks enabled. > > > 3. Cpus that are idle > > > > You should find all that in /proc/timer_list > > True. I could actually drop the vmstat cpumask support. > > > Now for CPUs that have full dynticks enabled, we probably need something > > in sysfs. We could dump the nohz cpumask somewhere. For now you can only grep > > the dmesg > > There is a nohz mode in /proc/timer_list right? > > > > 4. Cpus that are used for RCU. > > > > So, you mean those that aren't in extended grace period (between rcu_user_enter()/exit > > or rcu_idle_enter/exit)? > > No I mean cpus that have their RCU processing directed to another > processor. Ah, that is easier! In kernel/rcu/tree_plugin.c under #ifdef CONFIG_RCU_NOCB_CPU: cpumask_var_t get_rcu_nocb_mask(void) { return rcu_nocb_mask; } In include/linux/rcupdate.h: #if defined(CONFIG_TINY_RCU) || !defined(CONFIG_RCU_NOCB_CPU) static inline cpumask_var_t get_rcu_nocb_mask(void) { return NULL; } #else cpumask_var_t get_rcu_nocb_mask(void); #endif Then display the mask however you prefer. Modifying the mask is a very bad idea, and will void your warranty, etc., etc. Thanx, Paul -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org