From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail172.messagelabs.com (mail172.messagelabs.com [216.82.254.3]) by kanga.kvack.org (Postfix) with ESMTP id 57E416B007B for ; Mon, 23 Nov 2009 14:14:08 -0500 (EST) Message-ID: <4B0ADEF5.9040001@cs.helsinki.fi> Date: Mon, 23 Nov 2009 21:13:57 +0200 From: Pekka Enberg MIME-Version: 1.0 Subject: Re: lockdep complaints in slab allocator References: <20091118181202.GA12180@linux.vnet.ibm.com> <84144f020911192249l6c7fa495t1a05294c8f5b6ac8@mail.gmail.com> <1258709153.11284.429.camel@laptop> <84144f020911200238w3d3ecb38k92ca595beee31de5@mail.gmail.com> <1258714328.11284.522.camel@laptop> <4B067816.6070304@cs.helsinki.fi> <1258729748.4104.223.camel@laptop> <1259002800.5630.1.camel@penberg-laptop> <1259003425.17871.328.camel@calx> In-Reply-To: <1259003425.17871.328.camel@calx> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Matt Mackall Cc: Peter Zijlstra , paulmck@linux.vnet.ibm.com, linux-mm@kvack.org, cl@linux-foundation.org, LKML , Nick Piggin List-ID: Matt Mackall wrote: > This seems like a lot of work to paper over a lockdep false positive in > code that should be firmly in the maintenance end of its lifecycle? I'd > rather the fix or papering over happen in lockdep. True that. Is __raw_spin_lock() out of question, Peter?-) Passing the state is pretty invasive because of the kmem_cache_free() call in slab_destroy(). We re-enter the slab allocator from the outer edges which makes spin_lock_nested() very inconvenient. > Introducing extra cacheline pressure by passing to_destroy around also > seems like a good way to trickle away SLAB's narrow remaining > performance advantages. We can probably fix that to affect CONFIG_NUMA only which sucks already. 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