Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756937AbZKDQCJ (ORCPT ); Wed, 4 Nov 2009 11:02:09 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756856AbZKDQCI (ORCPT ); Wed, 4 Nov 2009 11:02:08 -0500 Received: from mx1.redhat.com ([209.132.183.28]:23561 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756657AbZKDQCI (ORCPT ); Wed, 4 Nov 2009 11:02:08 -0500 From: Jeff Moyer To: Vivek Goyal Cc: linux-kernel@vger.kernel.org, jens.axboe@oracle.com, nauman@google.com, dpshah@google.com, lizf@cn.fujitsu.com, ryov@valinux.co.jp, fernando@oss.ntt.co.jp, s-uchida@ap.jp.nec.com, taka@valinux.co.jp, guijianfeng@cn.fujitsu.com, balbir@linux.vnet.ibm.com, righi.andrea@gmail.com, m-ikeda@ds.jp.nec.com, akpm@linux-foundation.org, riel@redhat.com, kamezawa.hiroyu@jp.fujitsu.com Subject: Re: [PATCH 08/20] blkio: Add support for dynamic creation of cfq_groups References: <1257291837-6246-1-git-send-email-vgoyal@redhat.com> <1257291837-6246-9-git-send-email-vgoyal@redhat.com> X-PGP-KeyID: 1F78E1B4 X-PGP-CertKey: F6FE 280D 8293 F72C 65FD 5A58 1FF8 A7CA 1F78 E1B4 X-PCLoadLetter: What the f**k does that mean? Date: Wed, 04 Nov 2009 11:01:51 -0500 In-Reply-To: <1257291837-6246-9-git-send-email-vgoyal@redhat.com> (Vivek Goyal's message of "Tue, 3 Nov 2009 18:43:45 -0500") Message-ID: User-Agent: Gnus/5.110011 (No Gnus v0.11) Emacs/23.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1101 Lines: 34 Vivek Goyal writes: > + /* Do we need to take this reference */ > + if (!css_tryget(&blkcg->css)) > + return NULL;; Interesting question. It seems like, so long as you want to reference that cgroup, you need a reference on it. ->alloc will only give you one, so as long as we have pointers to these squirreled away, we need to bump the reference count. Please take a look at this before your next posting. > + > + cfqg = cfqg_of_blkg(blkiocg_lookup_group(blkcg, key)); > + if (cfqg || !create) > + goto done; > + > + cfqg = kzalloc_node(sizeof(*cfqg), GFP_ATOMIC | __GFP_ZERO, > + cfqd->queue->node); Do you really have to OR in __GFP_ZERO for kzalloc? > + cfqg = cfq_find_alloc_cfqg(cfqd, cgroup, create); > + if (!cfqg && create) > + cfqg = &cfqd->root_group; Hmm, is that really the behaviour you want? Cheers, Jeff -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/