From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Subject: Re: [PATCH] [RFC] kernel/cpu: Use lockref for online CPU reference counting Date: Wed, 17 Feb 2016 15:20:05 +0100 Message-ID: <20160217142005.GD6357@twins.programming.kicks-ass.net> References: <1455539803-13913-1-git-send-email-joonas.lahtinen@linux.intel.com> <20160215141755.GG6357@twins.programming.kicks-ass.net> <20160215170618.GL6375@twins.programming.kicks-ass.net> <1455612576.4977.11.camel@linux.intel.com> <20160216091440.GT6357@twins.programming.kicks-ass.net> <1455619863.4977.29.camel@linux.intel.com> <20160216110732.GU6357@twins.programming.kicks-ass.net> <1455713251.5622.9.camel@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) by gabe.freedesktop.org (Postfix) with ESMTPS id 81C276E9B9 for ; Wed, 17 Feb 2016 14:20:19 +0000 (UTC) Content-Disposition: inline In-Reply-To: <1455713251.5622.9.camel@linux.intel.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" To: Joonas Lahtinen Cc: "Gautham R. Shenoy" , Intel graphics driver community testing & development , Oleg Nesterov , Linux kernel development , David Hildenbrand , "Paul E. McKenney" , Ingo Molnar List-Id: intel-gfx@lists.freedesktop.org T24gV2VkLCBGZWIgMTcsIDIwMTYgYXQgMDI6NDc6MzFQTSArMDIwMCwgSm9vbmFzIExhaHRpbmVu IHdyb3RlOgo+IE9uIHRpLCAyMDE2LTAyLTE2IGF0IDEyOjA3ICswMTAwLCBQZXRlciBaaWpsc3Ry YSB3cm90ZToKPiA+IE9uIFR1ZSwgRmViIDE2LCAyMDE2IGF0IDEyOjUxOjAzUE0gKzAyMDAsIEpv b25hcyBMYWh0aW5lbiB3cm90ZToKPiA+ID4gUXVvdGluZyBteSBvcmlnaW5hbCBwYXRjaDsKPiA+ ID4gCj4gPiA+ICJTZWUgdGhlIEJ1Z3ppbGxhIGxpbmsgZm9yIG1vcmUgZGV0YWlscy4KPiA+IAo+ ID4gSWYgaXRzIG5vdCBpbiB0aGUgQ2hhbmdlbG9nIGl0IGRvZXNuJ3QgZXhpc3QuIFBhdGNoZXMg c2hvdWxkIGJlIHNlbGYKPiA+IGNvbnRhaW5lZCBhbmQgbm90IHJlZmVyIHRvIGV4dGVybmFsIHNv dXJjZXMgZm9yIGNyaXRpY2FsIGluZm9ybWF0aW9uLgo+IAo+IFRoZSBleGFjdCBsb2NraW5nIGNh c2UgaW4gQ1BVZnJlcSBkcml2ZXJzIGNhdXNpbmcgYSBzcGxhdCBpcyBkZXNjcmliZWQKPiBpbiB0 aGUgcGF0Y2guIERldGFpbHMgd2VyZSBhbHJlYWR5IGluY2x1ZGVkLCB0aGF0J3Mgd2h5IHRlcm0g Im1vcmUKPiBkZXRhaWxzIiB3YXMgdXNlZC4KCkJhcmVseS4gV2hhdCB3YXMgbm90IGRlc2NyaWJl ZCB3YXMgd2h5IHlvdSB3ZW50IHRvIHRpbmtlciB3aXRoIHRoZQpob3RwbHVnIGxvY2sgaW5zdGVh ZCBvZiBzYW5pdGl6aW5nIGNwdWZyZXEuIE5vciB3aHkgeW91ciBjaG9zZW4gc29sdXRpb24KaXMg Z29vZC4KCj4gVGhpcyBpcyBub3QgZXhhY3RseSB0YWtpbmcgdXMgY2xvc2VyIHRvIGEgZml4LCAK CldoeSB5b3UgdGhpbmsgd2UgY2FuIGRpc2N1c3MgZml4ZXMgaWYgeW91J3ZlIG5vdCBhY3R1YWxs eSBkZXNjcmliZWQgeW91cgpwcm9ibGVtIGlzIGJleW9uZCBtZS4KCgpfX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fXwpJbnRlbC1nZnggbWFpbGluZyBsaXN0Cklu dGVsLWdmeEBsaXN0cy5mcmVlZGVza3RvcC5vcmcKaHR0cHM6Ly9saXN0cy5mcmVlZGVza3RvcC5v cmcvbWFpbG1hbi9saXN0aW5mby9pbnRlbC1nZngK From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934572AbcBQOUZ (ORCPT ); Wed, 17 Feb 2016 09:20:25 -0500 Received: from bombadil.infradead.org ([198.137.202.9]:40079 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934551AbcBQOUW (ORCPT ); Wed, 17 Feb 2016 09:20:22 -0500 Date: Wed, 17 Feb 2016 15:20:05 +0100 From: Peter Zijlstra To: Joonas Lahtinen Cc: Oleg Nesterov , Intel graphics driver community testing & development , Linux kernel development , Ingo Molnar , David Hildenbrand , "Paul E. McKenney" , "Gautham R. Shenoy" , Chris Wilson , Daniel Vetter Subject: Re: [PATCH] [RFC] kernel/cpu: Use lockref for online CPU reference counting Message-ID: <20160217142005.GD6357@twins.programming.kicks-ass.net> References: <1455539803-13913-1-git-send-email-joonas.lahtinen@linux.intel.com> <20160215141755.GG6357@twins.programming.kicks-ass.net> <20160215170618.GL6375@twins.programming.kicks-ass.net> <1455612576.4977.11.camel@linux.intel.com> <20160216091440.GT6357@twins.programming.kicks-ass.net> <1455619863.4977.29.camel@linux.intel.com> <20160216110732.GU6357@twins.programming.kicks-ass.net> <1455713251.5622.9.camel@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1455713251.5622.9.camel@linux.intel.com> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Feb 17, 2016 at 02:47:31PM +0200, Joonas Lahtinen wrote: > On ti, 2016-02-16 at 12:07 +0100, Peter Zijlstra wrote: > > On Tue, Feb 16, 2016 at 12:51:03PM +0200, Joonas Lahtinen wrote: > > > Quoting my original patch; > > > > > > "See the Bugzilla link for more details. > > > > If its not in the Changelog it doesn't exist. Patches should be self > > contained and not refer to external sources for critical information. > > The exact locking case in CPUfreq drivers causing a splat is described > in the patch. Details were already included, that's why term "more > details" was used. Barely. What was not described was why you went to tinker with the hotplug lock instead of sanitizing cpufreq. Nor why your chosen solution is good. > This is not exactly taking us closer to a fix, Why you think we can discuss fixes if you've not actually described your problem is beyond me.