From mboxrd@z Thu Jan 1 00:00:00 1970 From: Linus Torvalds Subject: Re: [PATCH 7/8] mm: reinstate ZERO_PAGE Date: Tue, 8 Sep 2009 07:13:55 -0700 (PDT) Message-ID: References: <20090908073119.GA29902@wotan.suse.de> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Return-path: In-Reply-To: <20090908073119.GA29902@wotan.suse.de> Sender: owner-linux-mm@kvack.org To: Nick Piggin Cc: Hugh Dickins , Andrew Morton , KAMEZAWA Hiroyuki , KOSAKI Motohiro , Rik van Riel , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org List-Id: linux-arch.vger.kernel.org On Tue, 8 Sep 2009, Nick Piggin wrote: > > Without looking closely, why is it a big problem to have a > !HAVE PTE SPECIAL case? Couldn't it just be a check for > pfn == zero_pfn that is conditionally compiled away for pte > special architectures anyway? At least traditionally, there wasn't a single zero_pfn, but multiple (for VIPT caches that have performance issues with aliases). But yeah, we could check just the pfn number, and allow any architecture to do it. Linus -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp1.linux-foundation.org ([140.211.169.13]:52553 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753788AbZIHOOt (ORCPT ); Tue, 8 Sep 2009 10:14:49 -0400 Date: Tue, 8 Sep 2009 07:13:55 -0700 (PDT) From: Linus Torvalds Subject: Re: [PATCH 7/8] mm: reinstate ZERO_PAGE In-Reply-To: <20090908073119.GA29902@wotan.suse.de> Message-ID: References: <20090908073119.GA29902@wotan.suse.de> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-arch-owner@vger.kernel.org List-ID: To: Nick Piggin Cc: Hugh Dickins , Andrew Morton , KAMEZAWA Hiroyuki , KOSAKI Motohiro , Rik van Riel , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org Message-ID: <20090908141355.jjBS9ebrAGiifrv1MEEp_3zUb3dz4e9cdhjvUb7nC7c@z> On Tue, 8 Sep 2009, Nick Piggin wrote: > > Without looking closely, why is it a big problem to have a > !HAVE PTE SPECIAL case? Couldn't it just be a check for > pfn == zero_pfn that is conditionally compiled away for pte > special architectures anyway? At least traditionally, there wasn't a single zero_pfn, but multiple (for VIPT caches that have performance issues with aliases). But yeah, we could check just the pfn number, and allow any architecture to do it. Linus