Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964861AbWJIVES (ORCPT ); Mon, 9 Oct 2006 17:04:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964862AbWJIVES (ORCPT ); Mon, 9 Oct 2006 17:04:18 -0400 Received: from gate.crashing.org ([63.228.1.57]:45257 "EHLO gate.crashing.org") by vger.kernel.org with ESMTP id S964861AbWJIVER (ORCPT ); Mon, 9 Oct 2006 17:04:17 -0400 Subject: Re: User switchable HW mappings & cie From: Benjamin Herrenschmidt To: Ingo Oeser Cc: Thomas =?ISO-8859-1?Q?Hellstr=F6m?= , linux-mm@kvack.org, Linux Kernel list , Hugh Dickins , Arnd Bergmann , Linus Torvalds , Nick Piggin In-Reply-To: <200610092036.50010.ioe-lkml@rameria.de> References: <1160347065.5926.52.camel@localhost.localdomain> <452A35FF.50009@tungstengraphics.com> <1160394662.10229.30.camel@localhost.localdomain> <200610092036.50010.ioe-lkml@rameria.de> Content-Type: text/plain Date: Tue, 10 Oct 2006 07:03:49 +1000 Message-Id: <1160427829.7752.21.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.8.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1478 Lines: 40 On Mon, 2006-10-09 at 20:36 +0200, Ingo Oeser wrote: > Hi all, > > On Monday, 9. October 2006 13:51, Benjamin Herrenschmidt wrote: > > > One problem that occurs is that the rule for ptes with non-backing > > > struct pages > > > Which I think was introduced in 2.6.16: > > > > > > pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT) > > > > > > cannot be honored, at least not with the DRM memory manager, since the > > > graphics object will be associated with a vma and not the underlying > > > physical address. User space will have vma->vm_pgoff as a handle to the > > > object, which may move around in graphics memory. > > > > That's a problem with VM_PFNMAP set indeed. get_user_pages() is a > > non-issue with VM_IO set too but I'm not sure about other code path that > > might try to hit here... though I think we don't hit that if MAP_SHARED, > > Nick ? > > Istn't this just a non-linear PFN mapping, you are describing here? > > Nick: > Cant your new fault consolidation code handle that? > AFAICS your new .fault handler just gets the > vma and pgoff and install the matching PTE via install_THINGIE() > or vm_insert_THINGIE() > > Or do I miss sth. here? It is somewhat yes. Ben. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/