From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760396AbXGYJqY (ORCPT ); Wed, 25 Jul 2007 05:46:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756276AbXGYJqO (ORCPT ); Wed, 25 Jul 2007 05:46:14 -0400 Received: from one.firstfloor.org ([213.235.205.2]:38607 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755609AbXGYJqO (ORCPT ); Wed, 25 Jul 2007 05:46:14 -0400 Date: Wed, 25 Jul 2007 11:46:05 +0200 From: Andi Kleen To: Peter Zijlstra Cc: Benjamin Herrenschmidt , Andi Kleen , Andrew Morton , Ingo Molnar , linux-kernel@vger.kernel.org, Hugh Dickins Subject: Re: [patch] mm: reduce pagetable-freeing latencies Message-ID: <20070725094605.GA9045@one.firstfloor.org> References: <20070724083855.GA858@elte.hu> <20070724015441.8604d85d.akpm@linux-foundation.org> <1185270045.5439.249.camel@localhost.localdomain> <1185312559.5439.276.camel@localhost.localdomain> <1185345850.8197.64.camel@twins> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1185345850.8197.64.camel@twins> User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > You could perhaps use C99 variable length arrays to avoid the stack > waste when not needed, however Andi once told me that generates rather > dubious code. It generates frame pointers, but that's not that bad. I'm not aware of any other bad side effects. Ok the compiler will limit your goto usage, but that's more a good thing. But since you always have to strictly limit the array in kernel code anyways you could as well just allocate the fixed limit. -Andi