From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Fri, 21 Dec 2007 11:20:52 +0100 From: Nick Piggin Subject: Re: [rfc][patch 2/2] xip: support non-struct page memory Message-ID: <20071221102052.GB28484@wotan.suse.de> References: <20071214133817.GB28555@wotan.suse.de> <20071214134106.GC28555@wotan.suse.de> <476A73F0.4070704@de.ibm.com> <476A7D21.7070607@de.ibm.com> <20071221004556.GB31040@wotan.suse.de> <476B9000.2090707@de.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <476B9000.2090707@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 , Heiko Carstens List-ID: On Fri, Dec 21, 2007 at 11:05:52AM +0100, Carsten Otte wrote: > Nick Piggin wrote: > >So then you're back to needing struct pages again. Do you allocate > >them at hotplug time? > They get allocated by cathing kernel page faults when accessing the > mem_map array and filling in pages on demand. This happens at hotplug > time, where we initialize the content of struct page. Yep OK. > >AFAIK, sparsemem keeps track of all sections for pfn_valid(), which would > >work. Any plans to convert s390 to it? ;) > I think vmem_map is superior to sparsemem, because a > single-dimensional mem_map array is faster work with (single step > lookup). And we've got plenty of virtual address space for the > vmem_map array on 64bit. But it doesn't still retain sparsemem sections behind that? Ie. so that pfn_valid could be used? (I admittedly don't know enough eabout the memory model code). -- 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