From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755555Ab2GEJ34 (ORCPT ); Thu, 5 Jul 2012 05:29:56 -0400 Received: from e28smtp05.in.ibm.com ([122.248.162.5]:46486 "EHLO e28smtp05.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754798Ab2GEJ3x (ORCPT ); Thu, 5 Jul 2012 05:29:53 -0400 Message-ID: <1341480578.23916.7.camel@ThinkPad-T420> Subject: Re: [PATCH powerpc 2/2] kfree the cache name of pgtable cache if SLUB is used From: Li Zhong To: Glauber Costa Cc: Christoph Lameter , LKML , Pekka Enberg , Matt Mackall , Benjamin Herrenschmidt , Paul Mackerras , linux-mm , PowerPC email list Date: Thu, 05 Jul 2012 17:29:38 +0800 In-Reply-To: <4FF54F18.50300@parallels.com> References: <1340617984.13778.37.camel@ThinkPad-T420> <1340618099.13778.39.camel@ThinkPad-T420> <1341392420.18505.41.camel@ThinkPad-T420> <4FF439D0.1000603@parallels.com> <1341452486.18505.49.camel@ThinkPad-T420> <4FF54F18.50300@parallels.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3-0ubuntu6 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 x-cbid: 12070509-8256-0000-0000-00000331BA9B Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2012-07-05 at 12:23 +0400, Glauber Costa wrote: > On 07/05/2012 05:41 AM, Li Zhong wrote: > > On Wed, 2012-07-04 at 16:40 +0400, Glauber Costa wrote: > >> On 07/04/2012 01:00 PM, Li Zhong wrote: > >>> On Tue, 2012-07-03 at 15:36 -0500, Christoph Lameter wrote: > >>>>> Looking through the emails it seems that there is an issue with alias > >>>>> strings. > >>> To be more precise, there seems no big issue currently. I just wanted to > >>> make following usage of kmem_cache_create (SLUB) possible: > >>> > >>> name = some string kmalloced > >>> kmem_cache_create(name, ...) > >>> kfree(name); > >> > >> Out of curiosity: Why? > >> This is not (currently) possible with the other allocators (may change > >> with christoph's unification patches), so you would be making your code > >> slub-dependent. > >> > > > > For slub itself, I think it's not good that: in some cases, the name > > string could be kfreed ( if it was kmalloced ) immediately after calling > > the cache create; in some other case, the name string needs to be kept > > valid until some init calls finished. > > > > I agree with you that it would make the code slub-dependent, so I'm now > > working on the consistency of the other allocators regarding this name > > string duplicating thing. > > If you really need to kfree the string, or even if it is easier for you > this way, it can be done. As a matter of fact, this is the case for me. > Just that your patch is not enough. Christoph has a patch that makes > this behavior consistent over all allocators. Sorry, I didn't know that. Seems I don't need to continue the half-done work in slab. If possible, would you please give me a link of the patch? Thank you. > This just needs to be pushed again to the tree. >