From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail191.messagelabs.com (mail191.messagelabs.com [216.82.242.19]) by kanga.kvack.org (Postfix) with ESMTP id 8DC0D6B01B2 for ; Thu, 17 Jun 2010 05:01:45 -0400 (EDT) Message-ID: <4C19E476.9010303@cs.helsinki.fi> Date: Thu, 17 Jun 2010 12:01:42 +0300 From: Pekka Enberg MIME-Version: 1.0 Subject: Re: [RFC] slub: Simplify boot kmem_cache_cpu allocations References: <4C189119.5050801@kernel.org> <4C190748.7030400@kernel.org> <4C19E19D.2020802@kernel.org> In-Reply-To: <4C19E19D.2020802@kernel.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Tejun Heo Cc: Christoph Lameter , David Rientjes , linux-mm@kvack.org List-ID: On 6/17/10 11:49 AM, Tejun Heo wrote: > Hello, > > On 06/16/2010 07:35 PM, Christoph Lameter wrote: >>> It's primarily controlled by PERCPU_DYNAMIC_RESERVE. I don't think >>> there will be any systematic way to do it other than sizing it >>> sufficiently. Can you calculate the upper bound? The constant has >>> been used primarily for optimization so how it's used needs to be >>> audited if we wanna guarantee free space in the first chunk but I >>> don't think it would be too difficult. >> >> The upper bound is SLUB_PAGE_SHIFT * sizeof(struct kmem_cache_cpu). >> >> Thats usually 14 * 104 bytes = 1456 bytes. This may increase to more >> than 8k given the future plans to add queues into kmem_cache_cpu. > > Alright, will work on that. Does slab allocator guarantee to return > NULL if called before initialized or is it undefined? If latter, is > there a way to determine whether slab is initialized yet? It's undefined and you can use slab_is_available() to check if it's available or not. -- 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