From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-yh0-f44.google.com (mail-yh0-f44.google.com [209.85.213.44]) by kanga.kvack.org (Postfix) with ESMTP id E6A956B0085 for ; Thu, 4 Dec 2014 16:19:16 -0500 (EST) Received: by mail-yh0-f44.google.com with SMTP id c41so8613921yho.31 for ; Thu, 04 Dec 2014 13:19:16 -0800 (PST) Received: from mail-qa0-x234.google.com (mail-qa0-x234.google.com. [2607:f8b0:400d:c00::234]) by mx.google.com with ESMTPS id gt10si19155149qcb.1.2014.12.04.13.19.15 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Thu, 04 Dec 2014 13:19:16 -0800 (PST) Received: by mail-qa0-f52.google.com with SMTP id dc16so12697530qab.11 for ; Thu, 04 Dec 2014 13:19:15 -0800 (PST) Date: Thu, 4 Dec 2014 16:19:12 -0500 From: Tejun Heo Subject: Re: [RFC v2] percpu: Add a separate function to merge free areas Message-ID: <20141204211912.GG4080@htj.dyndns.org> References: <547E3E57.3040908@ixiacom.com> <20141204175713.GE2995@htj.dyndns.org> <5480BFAA.2020106@ixiacom.com> <20141204205202.GP29748@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: Christoph Lameter Cc: Al Viro , Leonard Crestez , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Sorin Dumitru On Thu, Dec 04, 2014 at 03:15:27PM -0600, Christoph Lameter wrote: > On Thu, 4 Dec 2014, Al Viro wrote: > > > ... except that somebody has not known that and took refcounts on e.g. > > vfsmounts into percpu. With massive amounts of hilarity once docker folks > > started to test the workloads that created/destroyed those in large amounts. > > Well, vfsmounts being a performance issue is a bit weird and unexpected. Docker usage is pretty wide-spread now, making what used to be siberia-cold paths hot enough to cause actual scalability issues. Besides, we're now using percpu_ref for things like aio and cgroup control structures which can be created and destroyed quite frequently. I don't think we can say these are "weird" use cases anymore. Thanks. -- tejun -- 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