Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755026AbbG3KFA (ORCPT ); Thu, 30 Jul 2015 06:05:00 -0400 Received: from mail-io0-f182.google.com ([209.85.223.182]:34456 "EHLO mail-io0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752103AbbG3KE7 (ORCPT ); Thu, 30 Jul 2015 06:04:59 -0400 MIME-Version: 1.0 In-Reply-To: References: <1438201199-2809-1-git-send-email-Waiman.Long@hp.com> Date: Thu, 30 Jul 2015 13:04:58 +0300 Message-ID: Subject: Re: [PATCH] proc: change proc_subdir_lock to a rwlock From: Alexey Dobriyan To: "Eric W. Biederman" Cc: Waiman Long , Andrew Morton , Nicolas Dichtel , Al Viro , Linux Kernel , Scott J Norton , Douglas Hatch Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 859 Lines: 24 On Thu, Jul 30, 2015 at 1:21 AM, Eric W. Biederman wrote: > Two quick questions. > > - What motivates this work? Are you seeing lots of > parallel reads on proc? Well, yes, benchmark looks like very synthetic. But even gcc opens /proc/meminfo, so might as well apply the change. Patch looks like obviously correct to me. > - Why not rcu? Additions and removal of proc generic > files is very rare. Conversion to rcu for reads should > perform better and not take much more work. If you want proc locking to be understood by ~10 people on the planet then yes, there is RCU. :-) -- 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/