From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Fri, 21 Dec 2007 11:14:19 +0100 From: Nick Piggin Subject: Re: [rfc][patch 2/2] xip: support non-struct page memory Message-ID: <20071221101419.GA28484@wotan.suse.de> References: <20071214133817.GB28555@wotan.suse.de> <20071214134106.GC28555@wotan.suse.de> <476A73F0.4070704@de.ibm.com> <476A7D21.7070607@de.ibm.com> <476A8133.5050809@de.ibm.com> <20071221005049.GC31040@wotan.suse.de> <476B8F2B.7010409@de.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <476B8F2B.7010409@de.ibm.com> Sender: owner-linux-mm@kvack.org Return-Path: To: carsteno@de.ibm.com Cc: Jared Hulbert , Linux Memory Management List , Martin Schwidefsky List-ID: On Fri, Dec 21, 2007 at 11:02:19AM +0100, Carsten Otte wrote: > Nick Piggin wrote: > >You wouldn't even need to store it in the vm_area_struct -- you could just > >set up eg. an rb tree of flash extents, and have a function that looks up > >that tree for you. > We have a list aready, and I don't see the number of plugged extents > get so large that rb tree saves us CPU cycles over a list implementation. > Martin Schwidefsky suggested to use a bit in the page table entry to > prevent refcounting. fault() could set it up proper for xip pages. > That would be way faster then walking a list. Would that be an option? I thought s390 was short on OS-available pte bits. There are a couple of other nice things to use them for, so I'd rather not for this if possible (it is not so critical if you can use a list, I would have thought) -- 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