From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail172.messagelabs.com (mail172.messagelabs.com [216.82.254.3]) by kanga.kvack.org (Postfix) with ESMTP id BB3FA8D003B for ; Fri, 4 Feb 2011 16:28:33 -0500 (EST) Received: from d03relay01.boulder.ibm.com (d03relay01.boulder.ibm.com [9.17.195.226]) by e34.co.us.ibm.com (8.14.4/8.13.1) with ESMTP id p14LHCgR006664 for ; Fri, 4 Feb 2011 14:17:12 -0700 Received: from d03av04.boulder.ibm.com (d03av04.boulder.ibm.com [9.17.195.170]) by d03relay01.boulder.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id p14LSSlG157514 for ; Fri, 4 Feb 2011 14:28:28 -0700 Received: from d03av04.boulder.ibm.com (loopback [127.0.0.1]) by d03av04.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id p14LSRE0006667 for ; Fri, 4 Feb 2011 14:28:27 -0700 Subject: Re: [RFC][PATCH 1/6] count transparent hugepage splits From: Dave Hansen In-Reply-To: <20110204211825.GJ30909@random.random> References: <20110201003357.D6F0BE0D@kernel> <20110201003358.98826457@kernel> <20110204211825.GJ30909@random.random> Content-Type: text/plain; charset="ANSI_X3.4-1968" Date: Fri, 04 Feb 2011 13:28:25 -0800 Message-ID: <1296854905.6737.2631.camel@nimitz> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Andrea Arcangeli Cc: David Rientjes , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Michael J Wolf On Fri, 2011-02-04 at 22:18 +0100, Andrea Arcangeli wrote: > On Thu, Feb 03, 2011 at 01:22:14PM -0800, David Rientjes wrote: > > i.e. no global locking, but we've accepted the occassional off-by-one > > error (even though splitting of hugepages isn't by any means lightning > > fast and the overhead of atomic ops would be negligible). > > Agreed losing an increment is not a problem, but in very large systems > it will become a bottleneck. It's not super urgent, but I think it > needs to become a per-cpu counter sooner than later (not needed > immediately but I would appreciate an incremental patch soon to > address that). Seems like something that would be fairly trivial with the existing count_vm_event() infrastructure. Any reason not to use that? I'll be happy to tack a patch on to my series. -- Dave -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org