Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758297Ab3CYP1e (ORCPT ); Mon, 25 Mar 2013 11:27:34 -0400 Received: from a192-102.smtp-out.amazonses.com ([199.255.192.102]:19365 "EHLO a192-102.smtp-out.amazonses.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758128Ab3CYP1d (ORCPT ); Mon, 25 Mar 2013 11:27:33 -0400 X-Greylist: delayed 566 seconds by postgrey-1.27 at vger.kernel.org; Mon, 25 Mar 2013 11:27:33 EDT Date: Mon, 25 Mar 2013 15:18:06 +0000 From: Christoph Lameter X-X-Sender: cl@gentwo.org To: Frederic Weisbecker cc: "Paul E. McKenney" , Steven Rostedt , Rob Landley , linux-kernel@vger.kernel.org, josh@joshtriplett.org, zhong@linux.vnet.ibm.com, khilman@linaro.org, geoff@infradead.org, tglx@linutronix.de Subject: Re: [PATCH] nohz1: Documentation In-Reply-To: Message-ID: <0000013da220b8b2-ed8dbc75-ac8c-4e1c-94df-c62f1625ec3a-000000@email.amazonses.com> References: <20130318222548.GG3656@linux.vnet.ibm.com> <1363822338.6345.33.camel@gandalf.local.home> <20130320235545.GL3637@linux.vnet.ibm.com> <0000013d8db514e4-bf492080-82c9-412a-90b8-54ddc1463e4b-000000@email.amazonses.com> <20130321171518.GW3637@linux.vnet.ibm.com> <0000013d8e3f58ce-0f6ea95f-780a-49c1-a633-5aa0cf3e5040-000000@email.amazonses.com> <20130321185821.GF3637@linux.vnet.ibm.com> <0000013d8e8d24fd-d2931c45-2722-46d1-8b47-2ef11e21096d-000000@email.amazonses.com> <20130321205054.GI3637@linux.vnet.ibm.com> <0000013d9289cebc-e6380265-3a74-4343-b851-765f785a3754-000000@email.amazonses.com> <20130322162820.GN3637@linux.vnet.ibm.com> <0000013da1f6170e-7b247826-93a9-4c2d-a316-ba3b0597a805-000000@email.amazonses.com> User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-SES-Outgoing: 199.255.192.102 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 961 Lines: 21 On Mon, 25 Mar 2013, Frederic Weisbecker wrote: > > The vm kernel threads do no useful work if no system calls are being done. > > If there is no kernel action then they can be deferred indefinitely. > > > > We can certainly add some user deferrable timer_list. But that's going > to be for extreme usecases (those who require pure isolation) because > we'll need to settle that with a timer reprogramming into user/kernel > boundaries. That won't be free. These timers are already marked deferrable and are deferred for the idle dynticks case. Could we reuse the same logic? See timer.h around the define of TIMER_DEFERRABLE. I just assumed so far that the dyntick idle logic would have been used for this case. -- 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/