From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail144.messagelabs.com (mail144.messagelabs.com [216.82.254.51]) by kanga.kvack.org (Postfix) with SMTP id CB03B6B0044 for ; Thu, 5 Nov 2009 12:56:41 -0500 (EST) Received: from localhost (smtp.ultrahosting.com [127.0.0.1]) by smtp.ultrahosting.com (Postfix) with ESMTP id 9C76882C83D for ; Thu, 5 Nov 2009 13:03:24 -0500 (EST) Received: from smtp.ultrahosting.com ([74.213.175.253]) by localhost (smtp.ultrahosting.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id OBSjj5xKkJ2T for ; Thu, 5 Nov 2009 13:03:20 -0500 (EST) Received: from V090114053VZO-1 (unknown [74.213.171.31]) by smtp.ultrahosting.com (Postfix) with ESMTP id D595B7003D9 for ; Thu, 5 Nov 2009 10:18:35 -0500 (EST) Date: Thu, 5 Nov 2009 10:10:56 -0500 (EST) From: Christoph Lameter Subject: Re: [MM] Make mm counters per cpu instead of atomic In-Reply-To: <20091105101650.45204e4e.kamezawa.hiroyu@jp.fujitsu.com> Message-ID: References: <20091105101650.45204e4e.kamezawa.hiroyu@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org To: KAMEZAWA Hiroyuki Cc: "hugh.dickins@tiscali.co.uk" , linux-mm@kvack.org, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, Tejun Heo List-ID: On Thu, 5 Nov 2009, KAMEZAWA Hiroyuki wrote: > Hmm, I don't fully understand _new_ percpu but... > In logical (even if not realistic), x86-32 supports up to 512 ? cpus in Kconfig. > BIGSMP. x86-32 only supports 32 processors. Plus per cpu areas are only allocated for the possible processors. > Then, if 65536 process runs, this consumes > > 65536(nr_proc) * 8 (size) * 512(cpus) = 256MBytes. With 32 possible cpus this results in 16m of per cpu space use. -- 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