Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753108AbaFTTKc (ORCPT ); Fri, 20 Jun 2014 15:10:32 -0400 Received: from mail-qa0-f43.google.com ([209.85.216.43]:60324 "EHLO mail-qa0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751114AbaFTTKa (ORCPT ); Fri, 20 Jun 2014 15:10:30 -0400 Date: Fri, 20 Jun 2014 15:10:25 -0400 From: Tejun Heo To: Li Zefan Cc: LKML , Cgroups Subject: Re: [PATCH 3/5] cgroup: fix mount failure in a corner case Message-ID: <20140620191025.GA28324@mtj.dyndns.org> References: <53994943.60703@huawei.com> <5399496D.6060003@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5399496D.6060003@huawei.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 12, 2014 at 02:32:13PM +0800, Li Zefan wrote: > @@ -1677,6 +1679,22 @@ static struct dentry *cgroup_mount(struct file_system_type *fs_type, > goto out_unlock; > } > > + /* > + * If some subsystems have been bound to existing cgroup hierarchies, > + * but those hierachies are being destroyed, let's wait a little bit > + * and retry. > + */ > + for_each_subsys(ss, i) { > + if (!(opts.subsys_mask & (1 << i))) > + continue; > + if (!percpu_ref_alive(&ss->root->cgrp.self.refcnt)) { Can't we just do tryget_live() instead and then put before retrying? It's not exactly a hot path and the operations are dirt cheap anyway. Thanks. -- tejun -- 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/