From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Mon, 5 May 2008 08:23:34 -0700 (PDT) From: Linus Torvalds Subject: Re: [rfc][patch 0/3] bootmem2: a memory block-oriented boot time allocator In-Reply-To: <20080505095938.326928514@symbol.fehenstaub.lan> Message-ID: References: <20080505095938.326928514@symbol.fehenstaub.lan> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Johannes Weiner Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Ingo Molnar , Andi Kleen , Yinghai Lu , Andrew Morton , Yasunori Goto List-ID: On Mon, 5 May 2008, Johannes Weiner wrote: > > here is a bootmem allocator replacement that uses one bitmap for all > available pages and works with a model of contiguous memory blocks > that reside on nodes instead of nodes only as the current allocator > does. Won't this have problems with huge non-contiguous areas? Some setups have traditionally had node memory separated in physical space by the high bits of the memory address, and using a single bitmap for such things would potentially be basically impossible - even with a single bit per page, the "span" of possible pages is potentially just too high, even if the nodes themselves don't have tons of memory, because the memory is just very spread out - and allocating the initial bitmap may not work reliably. Now, admittedly I don't know if we even support that kind of thing or if people really do things that way any more, so maybe it's not an issue. Linus -- 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