Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261872AbVEPUvw (ORCPT ); Mon, 16 May 2005 16:51:52 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261873AbVEPUvw (ORCPT ); Mon, 16 May 2005 16:51:52 -0400 Received: from dvhart.com ([64.146.134.43]:55969 "EHLO localhost.localdomain") by vger.kernel.org with ESMTP id S261872AbVEPUvo (ORCPT ); Mon, 16 May 2005 16:51:44 -0400 Date: Mon, 16 May 2005 13:51:36 -0700 From: "Martin J. Bligh" Reply-To: "Martin J. Bligh" To: christoph , Dave Hansen , Andy Whitcroft Cc: linux-mm , shai@scalex86.org, Linux Kernel Mailing List Subject: Re: [PATCH] Factor in buddy allocator alignment requirements in node memory alignment Message-ID: <731890000.1116276696@flay> In-Reply-To: References: <1116274451.1005.106.camel@localhost> X-Mailer: Mulberry/2.1.2 (Linux/x86) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1610 Lines: 44 --On Monday, May 16, 2005 12:43:17 -0700 christoph wrote: > On Mon, 16 May 2005, Dave Hansen wrote: > >> On Mon, 2005-05-16 at 12:05 -0700, christoph wrote: >> > Memory for nodes on i386 is currently aligned on 2 MB boundaries. >> > However, the buddy allocator needs pages to be aligned on >> > PAGE_SIZE << MAX_ORDER which is 8MB if MAX_ORDER = 11. >> >> Why do you need this? Are you planning on allowing NUMA KVA remap pages >> to be handed over to the buddy allocator? That would be a major >> departure from what we do now, and I'd be very interested in seeing how >> that is implemented before a infrastructure for it goes in. > > Because the buddy allocator is complaining about wrongly allocated zones! > > in page_alloc.c: > > static void __init free_area_init_core(struct pglist_data *pgdat, > unsigned long *zones_size, unsigned long *zholes_size) > { > ... > > const unsigned long zone_required_alignment = 1UL << (MAX_ORDER-1); > > ... > > if ((zone_start_pfn) & (zone_required_alignment-1)) > printk(KERN_CRIT "BUG: wrong zone alignment, it will crash\n"); IIRC, we decided that warning was worthless ... and I *think* Andy fixed it to do non-aligned zones, though it might have been someone else. Andy, can you remember what you did to fix this up? M. - 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/