From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751593Ab3K1XP7 (ORCPT ); Thu, 28 Nov 2013 18:15:59 -0500 Received: from shards.monkeyblade.net ([149.20.54.216]:47313 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751072Ab3K1XP4 (ORCPT ); Thu, 28 Nov 2013 18:15:56 -0500 Date: Thu, 28 Nov 2013 18:15:54 -0500 (EST) Message-Id: <20131128.181554.1888077442034865299.davem@davemloft.net> To: hannes@stressinduktion.org Cc: eric.dumazet@gmail.com, jongman.heo@samsung.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] inet: further fixes of possible seqlock deadlocks From: David Miller In-Reply-To: <20131128221926.GG24171@order.stressinduktion.org> References: <1385672502.5352.38.camel@edumazet-glaptop2.roam.corp.google.com> <20131128212700.GF24171@order.stressinduktion.org> <20131128221926.GG24171@order.stressinduktion.org> X-Mailer: Mew version 6.5 on Emacs 24.1 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.1 (shards.monkeyblade.net [0.0.0.0]); Thu, 28 Nov 2013 15:15:56 -0800 (PST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Hannes Frederic Sowa Date: Thu, 28 Nov 2013 23:19:26 +0100 > I don't really understand why we distinguish between _BH and plain ICMP stat > calls then. > > The non-_BH versions deactivate interrupts when updating the per-cpu counter. This level of distinction exists back in the day where we did per-cpu counters by hand. We used to have a BH counter and a non-BH counter for each statistic and it really helped performance wise. These days most of that may not be so relevant any more.