From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933634AbbFWQWI (ORCPT ); Tue, 23 Jun 2015 12:22:08 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:36433 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932566AbbFWQV7 (ORCPT ); Tue, 23 Jun 2015 12:21:59 -0400 Date: Tue, 23 Jun 2015 18:21:46 +0200 From: Peter Zijlstra To: Davidlohr Bueso Cc: oleg@redhat.com, paulmck@linux.vnet.ibm.com, tj@kernel.org, mingo@redhat.com, linux-kernel@vger.kernel.org, der.herr@hofr.at, riel@redhat.com, viro@ZenIV.linux.org.uk, torvalds@linux-foundation.org Subject: Re: [RFC][PATCH 00/13] percpu rwsem -v2 Message-ID: <20150623162146.GC3644@twins.programming.kicks-ass.net> References: <20150622121623.291363374@infradead.org> <1435075803.2059.1.camel@stgolabs.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1435075803.2059.1.camel@stgolabs.net> 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 Tue, Jun 23, 2015 at 09:10:03AM -0700, Davidlohr Bueso wrote: > On Mon, 2015-06-22 at 14:16 +0200, Peter Zijlstra wrote: > > This series converts the cpu hotplug lock into a percpu-rwsem to provide a 3rd > > user. > > Curious, why not also mem hotplug? It seems to use the exact same > locking mayhem than cpu. Because it looks like they 'forgot' to copy the notifiers and therefore I suspect we could simplify things. We might not need the recursive nonsense. But I've not yet actually looked at it much. I was indeed greatly saddened that these people copied cpu hotplug; clearly they had not gotten the memo that cpu hotplug is a trainwreck.