From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752768AbcAVIAS (ORCPT ); Fri, 22 Jan 2016 03:00:18 -0500 Received: from casper.infradead.org ([85.118.1.10]:58136 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752730AbcAVIAM (ORCPT ); Fri, 22 Jan 2016 03:00:12 -0500 Date: Fri, 22 Jan 2016 09:00:04 +0100 From: Peter Zijlstra To: Wang Nan Cc: linux-kernel@vger.kernel.org, pi3orama@163.com Subject: Re: [PATCH] perf core: Get rid of 'uses dynamic stack allocation' warning Message-ID: <20160122080004.GN6357@twins.programming.kicks-ass.net> References: <1453445521-230804-1-git-send-email-wangnan0@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1453445521-230804-1-git-send-email-wangnan0@huawei.com> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jan 22, 2016 at 06:52:01AM +0000, Wang Nan wrote: > On s390 with CONFIG_WARN_DYNAMIC_STACK set, 'uses dynamic stack > allocation' warning is issued when defining 'struct perf_sample_data' > local variable. > > This patch suppress this warning by allocating extra 255 bytes and > compute aligned pointer manually. I've seen the warning and always wondered wtf it was about. This Changelog doesn't actually explain what the problem is, so I cannot judge the solution. That said, 255 extra bytes does sound excessive just to avoid a warn.