From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1031331AbWI1Bzn (ORCPT ); Wed, 27 Sep 2006 21:55:43 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1031332AbWI1Bzn (ORCPT ); Wed, 27 Sep 2006 21:55:43 -0400 Received: from dsl027-180-168.sfo1.dsl.speakeasy.net ([216.27.180.168]:62136 "EHLO sunset.davemloft.net") by vger.kernel.org with ESMTP id S1031331AbWI1Bzm (ORCPT ); Wed, 27 Sep 2006 21:55:42 -0400 Date: Wed, 27 Sep 2006 18:55:41 -0700 (PDT) Message-Id: <20060927.185541.02300409.davem@davemloft.net> To: suresh.b.siddha@intel.com Cc: akpm@osdl.org, hugh@veritas.com, linux-kernel@vger.kernel.org, asit.k.mallick@intel.com Subject: Re: [patch] mm: fix a race condition under SMC + COW From: David Miller In-Reply-To: <20060927172355.B12423@unix-os.sc.intel.com> References: <20060927151507.A12423@unix-os.sc.intel.com> <20060927.155442.71092068.davem@davemloft.net> <20060927172355.B12423@unix-os.sc.intel.com> X-Mailer: Mew version 4.2 on Emacs 21.4 / Mule 5.0 (SAKAKI) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org From: "Siddha, Suresh B" Date: Wed, 27 Sep 2006 17:23:55 -0700 > I am flushing the pte entry in ptep_clear_flush() and it is Ok not > to do another TLB flush after doing set_pte_at(). > > On Sparc64, this new set_pte_at() (after ptep_clear_flush) will not batch > any TLB flush as the previous pte contents were zero. > > We are Ok with this patch, isn't it? Ok, it seems PowerPC also has the "don't do anything if previous PTE was zero" logic. So yes, it should be ok.