Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751561AbbHAUQJ (ORCPT ); Sat, 1 Aug 2015 16:16:09 -0400 Received: from g1t5425.austin.hp.com ([15.216.225.55]:38076 "EHLO g1t5425.austin.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751436AbbHAUQH (ORCPT ); Sat, 1 Aug 2015 16:16:07 -0400 From: "Long, Wai Man" To: Davidlohr Bueso CC: Peter Zijlstra , Ingo Molnar , Thomas Gleixner , "H. Peter Anvin" , "x86@kernel.org" , "linux-kernel@vger.kernel.org" , "Norton, Scott J" , "Hatch, Douglas B (HPS Linux PM)" Subject: RE: [PATCH v4 1/7] locking/pvqspinlock: Unconditional PV kick with _Q_SLOW_VAL Thread-Topic: [PATCH v4 1/7] locking/pvqspinlock: Unconditional PV kick with _Q_SLOW_VAL Thread-Index: AQHQzADm35klY6OeIk2+jBWeFTs3e533cA2AgAAkmWA= Date: Sat, 1 Aug 2015 20:12:34 +0000 Message-ID: <401F72D6D1DFE3499766D25AA4EED18A440D6B10@G2W2529.americas.hpqcorp.net> References: <1438395724-25910-1-git-send-email-Waiman.Long@hp.com> <1438395724-25910-2-git-send-email-Waiman.Long@hp.com> <1438452063.2249.98.camel@stgolabs.net> In-Reply-To: <1438452063.2249.98.camel@stgolabs.net> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [16.192.129.45] Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by mail.home.local id t71KGa4S018994 Content-Length: 1387 Lines: 29 Davidlohr, I am sorry that I forgot to put in your tag. Cheers, Longman -----Original Message----- From: linux-kernel-owner@vger.kernel.org [mailto:linux-kernel-owner@vger.kernel.org] On Behalf Of Davidlohr Bueso Sent: Saturday, August 01, 2015 2:01 PM To: Long, Wai Man Cc: Peter Zijlstra; Ingo Molnar; Thomas Gleixner; H. Peter Anvin; x86@kernel.org; linux-kernel@vger.kernel.org; Norton, Scott J; Hatch, Douglas B (HPS Linux PM) Subject: Re: [PATCH v4 1/7] locking/pvqspinlock: Unconditional PV kick with _Q_SLOW_VAL On Fri, 2015-07-31 at 22:21 -0400, Waiman Long wrote: > The smp_store_release() is not a full barrier. In order to avoid > missed wakeup, we may need to add memory barrier around locked and cpu > state variables adding to complexity. As the chance of spurious wakeup > is very low, it is easier and safer to just do an unconditional kick > at unlock time. > > Signed-off-by: Waiman Long Please keep tags from previous versions ;) -- 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/ ????{.n?+???????+%?????ݶ??w??{.n?+????{??G?????{ay?ʇڙ?,j??f???h?????????z_??(?階?ݢj"???m??????G????????????&???~???iO???z??v?^?m???? ????????I?