Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755882Ab1CRCTN (ORCPT ); Thu, 17 Mar 2011 22:19:13 -0400 Received: from mga09.intel.com ([134.134.136.24]:29069 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755555Ab1CRCTL (ORCPT ); Thu, 17 Mar 2011 22:19:11 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.63,203,1299484800"; d="scan'208";a="721435628" Subject: Re: [PATCH]x86: flush tlb if PGD entry is changed in i386 PAE mode From: Shaohua Li To: Ingo Molnar , Andrew Morton Cc: lkml , linux-mm , Rik van Riel , "y-goto@jp.fujitsu.com" , "Mallick, Asit K" In-Reply-To: <4D80B514.3030409@redhat.com> References: <1300246649.2337.95.camel@sli10-conroe> <4D80B514.3030409@redhat.com> Content-Type: text/plain; charset="UTF-8" Date: Fri, 18 Mar 2011 10:19:08 +0800 Message-ID: <1300414748.2337.137.camel@sli10-conroe> Mime-Version: 1.0 X-Mailer: Evolution 2.30.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1252 Lines: 29 On Wed, 2011-03-16 at 21:03 +0800, Rik van Riel wrote: > On 03/15/2011 11:37 PM, Shaohua Li wrote: > > According to intel CPU manual, every time PGD entry is changed in i386 PAE mode, > > we need do a full TLB flush. Current code follows this and there is comment > > for this too in the code. But current code misses the multi-threaded case. A > > changed page table might be used by several CPUs, every such CPU should flush > > TLB. > > Usually this isn't a problem, because we prepopulate all PGD entries at process > > fork. But when the process does munmap and follows new mmap, this issue will be > > triggered. When it happens, some CPUs will keep doing page fault. > > > > See: http://marc.info/?l=linux-kernel&m=129915020508238&w=2 > > > > Reported-by: Yasunori Goto > > Signed-off-by: Shaohua Li > > Tested-by: Yasunori Goto > > Reviewed-by: Rik van Riel Ingo & akpm, can you pick this one? Thanks, Shaohua -- 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/