From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761979AbXIUSsw (ORCPT ); Fri, 21 Sep 2007 14:48:52 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758567AbXIUSsq (ORCPT ); Fri, 21 Sep 2007 14:48:46 -0400 Received: from smtp2.linux-foundation.org ([207.189.120.14]:59217 "EHLO smtp2.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757374AbXIUSsp (ORCPT ); Fri, 21 Sep 2007 14:48:45 -0400 Date: Fri, 21 Sep 2007 11:48:55 -0700 (PDT) From: Linus Torvalds To: "Siddha, Suresh B" cc: clameter@sgi.com, 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: > > git commit 34feb2c83beb3bdf13535a36770f7e50b47ef299 started using quicklists > for freeing page table pages and removed the usage of tlb_remove_page() > > And looking at quicklist_free() and quicklist_free_page(), on a NUMA platform, > this can potentially free the page before the corresponding TLB caches > are flushed. Hmm? We only add them to the quicklists in the exact same places where we *used* to just free them entirely. So I don't see why semantics would have changed.. > Can we revert this commit for 2.6.23 and look at this code post 2.6.23? I'll happily revert it, but I want to understand this better, so more of an explanation of the codepath that actually does something wrong, please. Linus