From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762165AbXIUStQ (ORCPT ); Fri, 21 Sep 2007 14:49:16 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1760110AbXIUStA (ORCPT ); Fri, 21 Sep 2007 14:49:00 -0400 Received: from netops-testserver-3-out.sgi.com ([192.48.171.28]:36719 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1759454AbXIUSs7 (ORCPT ); Fri, 21 Sep 2007 14:48:59 -0400 Date: Fri, 21 Sep 2007 11:48:58 -0700 (PDT) From: Christoph Lameter X-X-Sender: clameter@schroedinger.engr.sgi.com To: "Siddha, Suresh B" cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, ak@suse.de, linux-kernel@vger.kernel.org, tony.luck@intel.com, asit.k.mallick@intel.com Subject: Re: x86_64: potential critical issue with quicklists and page table pages In-Reply-To: <20070921180742.GH20863@linux-os.sc.intel.com> Message-ID: References: <20070921180742.GH20863@linux-os.sc.intel.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 21 Sep 2007, Siddha, Suresh B wrote: > Essentially quicklist free routines are doing something like > __quicklist_free() > ... > if (unlikely(nid != numa_node_id())) { > __free_page(page); > ... > } > > .... > > > Now this will potentially cause a problem, if a cpu in someother node starts > using this page, while the corresponding TLB entries are still alive > in the original cpu which is still freeing the page table pages. Hmmm... Yes could be. > This potentially can cause SW failures and hard to debug issues like > http://www.ussg.iu.edu/hypermail/linux/kernel/0205.2/1254.html Cannot get to this page: Not Found The requested URL /hypermail/linux/kernel/0205.2/1254.htm was not found on this server. > Can we revert this commit for 2.6.23 and look at this code post 2.6.23? We can remove this piece alone since it was an optimization. --- include/linux/quicklist.h | 7 ------- 1 file changed, 7 deletions(-) Index: linux-2.6/include/linux/quicklist.h =================================================================== --- linux-2.6.orig/include/linux/quicklist.h 2007-09-21 11:46:44.000000000 -0700 +++ linux-2.6/include/linux/quicklist.h 2007-09-21 11:47:01.000000000 -0700 @@ -58,13 +58,6 @@ static inline void __quicklist_free(int struct quicklist *q; int nid = page_to_nid(page); - if (unlikely(nid != numa_node_id())) { - if (dtor) - dtor(p); - __free_page(page); - return; - } - q = &get_cpu_var(quicklist)[nr]; *(void **)p = q->page; q->page = p;