From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <47B49ADD.9010001@cs.helsinki.fi> Date: Thu, 14 Feb 2008 21:47:41 +0200 From: Pekka Enberg MIME-Version: 1.0 Subject: Re: [patch 2/5] slub: Fallback to kmalloc_large for failing higher order allocs References: <20080214040245.915842795@sgi.com> <20080214040313.616551392@sgi.com> <20080214140614.GE17641@csn.ul.ie> <47B49520.4070201@cs.helsinki.fi> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Christoph Lameter Cc: Mel Gorman , Nick Piggin , Andrew Morton , linux-mm@kvack.org List-ID: Christoph Lameter wrote: > That would mean reducing the number of objects that can be allocated from > the fastpath before we have to go to the page allocator again. Increasing > the number of fastpath uses vs slowpath increases the overall performance > of a slab. > > If we would use order 0 slab allocs for 4k slabs then every call to > slab_alloc would lead to a corresponding call to the page allocator. The > regression would not be fixed. We just add slab_alloc overhead to an > already bad page allocator call. Aah, I see. I wonder if we can fix up allocate_slab() to try with a smaller order as long as the size allows that? The only problem I can see is s->objects but I think we can just move that to be a per-slab variable. So sort of variable-order slabs kind of a thing. What do you think? Pekka -- 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