From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757482Ab2BBV7R (ORCPT ); Thu, 2 Feb 2012 16:59:17 -0500 Received: from merlin.infradead.org ([205.233.59.134]:42839 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751322Ab2BBV7Q convert rfc822-to-8bit (ORCPT ); Thu, 2 Feb 2012 16:59:16 -0500 Message-ID: <1328219944.2446.277.camel@twins> Subject: Re: [PATCH] backing-dev: use synchronize_rcu_expedited instead of synchronize_rcu From: Peter Zijlstra To: Mikulas Patocka Cc: axboe@kernel.dk, "Alasdair G. Kergon" , dm-devel@redhat.com, linux-kernel@vger.kernel.org, "Paul E. McKenney" Date: Thu, 02 Feb 2012 22:59:04 +0100 In-Reply-To: References: <1328042063.2446.250.camel@twins> Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT X-Mailer: Evolution 3.2.1- Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2012-02-02 at 15:43 -0500, Mikulas Patocka wrote: > Do you have some measurable use case where the user is removing block > devices so heavily that this causes a problem? Even one can be a problem, we're having people spend lots of time and effort to reduce machine wide jitter and interference. Adding it with such disregard isn't cool. There's no reason a management cpu adding or removing block devices should perturb the high-freq trading or industrial laser control running on the other side of the machine.