From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail203.messagelabs.com (mail203.messagelabs.com [216.82.254.243]) by kanga.kvack.org (Postfix) with ESMTP id 266D66B0055 for ; Wed, 15 Jul 2009 09:18:52 -0400 (EDT) Date: Wed, 15 Jul 2009 15:56:20 +0200 From: Nick Piggin Subject: Re: [RFC/PATCH] mm: Pass virtual address to [__]p{te,ud,md}_free_tlb() Message-ID: <20090715135620.GD7298@wotan.suse.de> References: <20090715074952.A36C7DDDB2@ozlabs.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090715074952.A36C7DDDB2@ozlabs.org> Sender: owner-linux-mm@kvack.org To: Benjamin Herrenschmidt Cc: Linux Memory Management , Linux-Arch , linux-kernel@vger.kernel.org, linuxppc-dev@ozlabs.org, Hugh Dickins List-ID: On Wed, Jul 15, 2009 at 05:49:47PM +1000, Benjamin Herrenschmidt wrote: > Upcoming paches to support the new 64-bit "BookE" powerpc architecture > will need to have the virtual address corresponding to PTE page when > freeing it, due to the way the HW table walker works. > > Basically, the TLB can be loaded with "large" pages that cover the whole > virtual space (well, sort-of, half of it actually) represented by a PTE > page, and which contain an "indirect" bit indicating that this TLB entry > RPN points to an array of PTEs from which the TLB can then create direct > entries. RPN is PFN in ppc speak, right? > Thus, in order to invalidate those when PTE pages are deleted, > we need the virtual address to pass to tlbilx or tlbivax instructions. Interesting arrangement. So are these last level ptes modifieable from userspace or something? If not, I wonder if you could manage them as another level of pointers with the existing pagetable functions? > The old trick of sticking it somewhere in the PTE page struct page sucks > too much, the address is almost readily available in all call sites and > almost everybody implemets these as macros, so we may as well add the > argument everywhere. I added it to the pmd and pud variants for consistency. > > Signed-off-by: Benjamin Herrenschmidt > --- > > I would like to merge the new support that depends on this in 2.6.32, > so unless there's major objections, I'd like this to go in early during > the merge window. We can sort out separately how to carry the patch > around in -next until then since the powerpc tree will have a dependency > on it. Can't see any problem with that. -- 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