Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758891Ab2HHQm0 (ORCPT ); Wed, 8 Aug 2012 12:42:26 -0400 Received: from mail.renton.name ([90.155.165.44]:39824 "EHLO beaver.old-horrors.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758837Ab2HHQmZ (ORCPT ); Wed, 8 Aug 2012 12:42:25 -0400 Date: Wed, 8 Aug 2012 20:40:33 +0400 From: Alexey Vlasov To: Mike Galbraith Cc: linux-kernel@vger.kernel.org, paulmck@linux.vnet.ibm.com Subject: Re: Attaching a process to cgroups Message-ID: <20120808164033.GB13735@beaver> References: <20120619185856.GC31797@beaver> <1340195298.15707.3.camel@marge.simpson.net> <20120725133637.GA9169@beaver> <1343224667.5745.67.camel@marge.simpson.net> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <1343224667.5745.67.camel@marge.simpson.net> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 964 Lines: 21 On Wed, Jul 25, 2012 at 03:57:47PM +0200, Mike Galbraith wrote: > > Hanging on read(): > > > > # strace -ttT cat /proc/cgroups > > > > 17:30:43.825005 fstat(1, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 13), ...}) = 0 <0.000005> > > 17:30:43.825048 open("/proc/cgroups", O_RDONLY) = 3 <0.000014> > > 17:30:43.825085 fstat(3, {st_mode=S_IFREG|0444, st_size=0, ...}) = 0 <0.000004> > > 17:30:43.825125 fadvise64(3, 0, 0, POSIX_FADV_SEQUENTIAL) = 0 <0.000005> > > 17:30:43.825161 read(3, "#subsys_name\thierarchy\tnum_cgrou"..., 32768) = 112 <7.447084> In general I've changed it to synchronize_rcu_expedited () and all the delays have gone both on writing and reading files from cgroups. -- BRGDS. Alexey Vlasov. -- 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/