From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f169.google.com (mail-pd0-f169.google.com [209.85.192.169]) by kanga.kvack.org (Postfix) with ESMTP id D542A6B0031 for ; Fri, 18 Apr 2014 16:18:31 -0400 (EDT) Received: by mail-pd0-f169.google.com with SMTP id fp1so1740520pdb.14 for ; Fri, 18 Apr 2014 13:18:31 -0700 (PDT) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org. [140.211.169.12]) by mx.google.com with ESMTP id c7si15545275pay.150.2014.04.18.13.18.30 for ; Fri, 18 Apr 2014 13:18:30 -0700 (PDT) Date: Fri, 18 Apr 2014 13:18:28 -0700 From: Andrew Morton Subject: Re: [PATCH -mm v2 1/2] mem-hotplug: implement get/put_online_mems Message-Id: <20140418131828.804a181e5b4364a704d786cc@linux-foundation.org> In-Reply-To: References: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Vladimir Davydov Cc: cl@linux-foundation.org, penberg@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, devel@openvz.org, Tang Chen , Zhang Yanfei , Toshi Kani , Xishi Qiu , Jiang Liu , "Rafael J. Wysocki" , David Rientjes , Wen Congyang , Yasuaki Ishimatsu , Lai Jiangshan On Mon, 7 Apr 2014 13:45:34 +0400 Vladimir Davydov wrote: > {un}lock_memory_hotplug, which is used to synchronize against memory > hotplug, is currently backed by a mutex, which makes it a bit of a > hammer - threads that only want to get a stable value of online nodes > mask won't be able to proceed concurrently. Also, it imposes some strong > locking ordering rules on it, which narrows down the set of its usage > scenarios. > > This patch introduces get/put_online_mems, which are the same as > get/put_online_cpus, but for memory hotplug, i.e. executing a code > inside a get/put_online_mems section will guarantee a stable value of > online nodes, present pages, etc. Well that seems a nice change. I added the important paragraph "lock_memory_hotplug()/unlock_memory_hotplug() are removed altogether." I'll Cc a large number of people who have recently worked on the memory hotplug code. Hopefully some of them will have time to review and test these patches, thanks. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org