From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Mon, 16 May 2005 12:43:17 -0700 (PDT) From: christoph Subject: Re: [PATCH] Factor in buddy allocator alignment requirements in node memory alignment In-Reply-To: <1116274451.1005.106.camel@localhost> Message-ID: References: <1116274451.1005.106.camel@localhost> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Dave Hansen Cc: linux-mm , shai@scalex86.org, Linux Kernel Mailing List List-ID: 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"); -- 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: aart@kvack.org