From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 7F183DDFA8 for ; Thu, 17 Jul 2008 08:16:25 +1000 (EST) Message-Id: From: Kumar Gala To: benh@kernel.crashing.org In-Reply-To: <1216244518.7740.205.camel@pasglop> Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes Mime-Version: 1.0 (Apple Message framework v926) Subject: Re: SW TLB MMU rework and SMP issues (pte read/write) Date: Wed, 16 Jul 2008 17:12:55 -0500 References: <1216174045.7740.152.camel@pasglop> <1216244518.7740.205.camel@pasglop> Cc: linuxppc-dev list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Jul 16, 2008, at 4:41 PM, Benjamin Herrenschmidt wrote: > On Wed, 2008-07-16 at 15:57 -0500, Kumar Gala wrote: >> This makes sense. I think we need to order the stores in set_pte_at >> regardless of CONFIG_SMP. > > Nah, that shouldn't be necessary. Yeah I finally came to that realization. >> Also, I think we should change pte_clear to >> use pte_update() so we only clear the low-order flag bits. Patch >> will >> be sent shortly for review. > > Well... at one point at least we did rely on a PTE page with all PTEs > cleared to be blank. It don't know if that's still the case, I need to > look. Doesn't look like we do anything special, we just call free_pages or __free_pages in arch/powerpc/mm/pgtable_32.c. - k