From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: [patch 7/8] slub: Adjust order boundaries and minimum objects per slab. From: Matt Mackall In-Reply-To: References: <20080215230811.635628223@sgi.com> <20080215230854.643455255@sgi.com> <47B6A928.7000309@cs.helsinki.fi> Content-Type: text/plain Date: Sat, 16 Feb 2008 14:20:59 -0600 Message-Id: <1203193259.6324.12.camel@cinder.waste.org> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Christoph Lameter Cc: Pekka Enberg , Mel Gorman , linux-mm@kvack.org List-ID: On Sat, 2008-02-16 at 11:00 -0800, Christoph Lameter wrote: > On Sat, 16 Feb 2008, Pekka Enberg wrote: > > > These look quite excessive from memory usage point of view. I saw you dropping > > DEFAULT_MAX_ORDER to 4 but it seems a lot for embedded guys, at least? > > What would be a good max order then? 4 means we can allocate a 64k segment > for 16 4k objects. Why are 4k objects even going through SLUB? What happens if we have 8k free and try to allocate one 4k object through SLUB? Using an order greater than 0 is generally frowned upon. Kernels can and do get into situations where they can't find two contiguous pages, which is why we've gone to so much trouble on x86 to fit into a single page of stack. -- Mathematics is the supreme nostalgia of our time. -- 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