From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 68E31C10F0E for ; Mon, 15 Apr 2019 15:25:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 47E8B20818 for ; Mon, 15 Apr 2019 15:25:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="lecSp0+j" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727673AbfDOPZz (ORCPT ); Mon, 15 Apr 2019 11:25:55 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:59520 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727372AbfDOPZy (ORCPT ); Mon, 15 Apr 2019 11:25:54 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=CPQA+mNJvI1vGfPejlJ8PSoFXrtpz7wLC6wSJjdw80Y=; b=lecSp0+jbSDLNuY1XH/WF4NRT qSiuQI4ukq+CxnkNt6xwabapyPjMpyOiwwZmUIjtl5+q0nLyuFqkGEmSi1xByb+fSGx6tUDSBhFrd alUJIsogDD58b1UjSxEoyBM5yrsUU0HlMp4jDpA3qHgdLPXoDOyYmemhq/uNLFetye0e/P9YT9qu8 IKbkUYu3E+lUnGIZ/thC2SbmP36iBx+lAQEt6a91uBh+uxfui8B/ee8wWmulXMn8XCFfHfcFf9YGq 4aKXa+PHRKY17okZ7NrrDIr9Ib+3q3/eoLlkvqJW09XGRCz6kNTYD+e1sWrF5AeV5gNRzCyWUK0v7 lAmV7Q15w==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1hG3UV-0003Wm-TK; Mon, 15 Apr 2019 15:25:52 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 0E64B23925996; Mon, 15 Apr 2019 17:25:49 +0200 (CEST) Date: Mon, 15 Apr 2019 17:25:49 +0200 From: Peter Zijlstra To: "chengjian (D)" Cc: huawei.libin@huawei.com, xiexiuqi@huawei.com, yangyingliang@huawei.com, mingo@redhat.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH] sched/fair: Use 'unsigned long' for group_shares,group_runnable Message-ID: <20190415152549.GQ11158@hirez.programming.kicks-ass.net> References: <20190413033234.30002-1-cj.chengjian@huawei.com> <20190415124617.GP11158@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Apr 15, 2019 at 11:20:31PM +0800, chengjian (D) wrote: > Hi, Peter > > > On 2019/4/15 20:46, Peter Zijlstra wrote: > > I write a demo about this, which I described it as overflow. I'm not saying there's no overflow, I'm saying there's nothing UB about it.