From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752817AbbFVPUg (ORCPT ); Mon, 22 Jun 2015 11:20:36 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:50358 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751682AbbFVPU1 (ORCPT ); Mon, 22 Jun 2015 11:20:27 -0400 Date: Mon, 22 Jun 2015 17:20:13 +0200 From: Peter Zijlstra To: "Paul E. McKenney" Cc: Dave Hansen , Andi Kleen , dave.hansen@linux.intel.com, akpm@linux-foundation.org, jack@suse.cz, viro@zeniv.linux.org.uk, eparis@redhat.com, john@johnmccutchan.com, rlove@rlove.org, tim.c.chen@linux.intel.com, linux-kernel@vger.kernel.org Subject: Re: [RFC][PATCH] fs: optimize inotify/fsnotify code for unwatched files Message-ID: <20150622152013.GW3644@twins.programming.kicks-ass.net> References: <20150619215025.4F689817@viggo.jf.intel.com> <20150619233306.GT25760@tassilo.jf.intel.com> <5584B62F.5080506@sr71.net> <20150620022135.GF3913@linux.vnet.ibm.com> <5585AAA0.1030305@sr71.net> <20150621013058.GH3913@linux.vnet.ibm.com> <20150622132821.GB12596@twins.programming.kicks-ass.net> <20150622151121.GK3913@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150622151121.GK3913@linux.vnet.ibm.com> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jun 22, 2015 at 08:11:21AM -0700, Paul E. McKenney wrote: > That depends on how slow the resulting slow global state would be. > We have some use cases (definitely KVM, perhaps also some of the VFS > code) that need the current speed, as opposed to the profound slowness > that three trips through synchronize_sched() would provide. But we have call_srcu() these days, not everything needs to use sync_srcu() anymore. Although I've not checked recently. > Plus we > would lose the ability to have SRCU readers on idle and offline CPUs. Are we actually doing that? offline CPUs in particular seems iffy, I don't think we need (or should) worry about that. I know its been an issue with regular RCU due to tracing, but I'm not sure we should care for it for SRCU. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in Please read the FAQ at http://www.tux.org/lkml/