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=-2.4 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID, 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 1C545C46471 for ; Mon, 6 Aug 2018 16:03:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C9FED217B9 for ; Mon, 6 Aug 2018 16:03:42 +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="bSkuTjxY" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C9FED217B9 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733132AbeHFSN0 (ORCPT ); Mon, 6 Aug 2018 14:13:26 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:48820 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730724AbeHFSNZ (ORCPT ); Mon, 6 Aug 2018 14:13:25 -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=8IaTbGiI2kBzPlXkTibDxExERHMd3REdT8BW2Nz2qnY=; b=bSkuTjxYN4NMHmlhw2dJhmPpJ P/0O5ZWufJug37n30eMX6zn9IQ0QpAMnZAkNcmK7ou43dU+XTgCRkMmrSLxP6K8g2QeSdU49zFQUk UKVCQQkrwn65ney/0EdNe2Jnp9GQB66ViYynnHVgRlOeS4wcg/b791Co6Qn7TbL5q8sJcAQTAGpKP qK6iCvfApWakeMjob3w18AAJ53W+BD+pkUu590MFo5HHgYEY4zeE3PDYCg9VX6qeP2R/r5aVuarbv nPOtSdbtiXpN80LRv/aCX3eAYocf/L9kvVddGLD3aVruUatVCx0nrIh8Rcf/LEUn+5bFekxQ4rWVI 17xROMavw==; 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 1fmhyl-0006hP-05; Mon, 06 Aug 2018 16:03:31 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 7547920589AA1; Mon, 6 Aug 2018 18:03:29 +0200 (CEST) Date: Mon, 6 Aug 2018 18:03:29 +0200 From: Peter Zijlstra To: Johannes Weiner Cc: Ingo Molnar , Andrew Morton , Linus Torvalds , Tejun Heo , Suren Baghdasaryan , Daniel Drake , Vinayak Menon , Christopher Lameter , Mike Galbraith , Shakeel Butt , Peter Enderborg , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@fb.com Subject: Re: [PATCH 8/9] psi: pressure stall information for CPU, memory, and IO Message-ID: <20180806160329.GP2494@hirez.programming.kicks-ass.net> References: <20180801151958.32590-1-hannes@cmpxchg.org> <20180801151958.32590-9-hannes@cmpxchg.org> <20180803165641.GA2476@hirez.programming.kicks-ass.net> <20180806151928.GB9888@cmpxchg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180806151928.GB9888@cmpxchg.org> User-Agent: Mutt/1.10.0 (2018-05-17) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 06, 2018 at 11:19:28AM -0400, Johannes Weiner wrote: > On Fri, Aug 03, 2018 at 06:56:41PM +0200, Peter Zijlstra wrote: > > On Wed, Aug 01, 2018 at 11:19:57AM -0400, Johannes Weiner wrote: > > > + u32 uninitialized_var(nonidle); > > > > urgh.. I can see why the compiler got confused. Dodgy :-) > > :-) I think we can make this cleaner. Something like this (modulo the > READ_ONCE/WRITE_ONCE you pointed out in the other email)? > > @@ -244,60 +287,17 @@ static bool psi_update_stats(struct psi_group *group) > */ > for_each_online_cpu(cpu) { > struct psi_group_cpu *groupc = per_cpu_ptr(group->pcpu, cpu); > + u32 nonidle; > + > + nonidle = read_update_delta(groupc, PSI_NONIDLE, cpu); > + nonidle = nsecs_to_jiffies(nonidle); > + nonidle_total += nonidle; > + > + for (s = 0; s < PSI_NONIDLE; s++) { > + u32 delta; > + > + delta = read_update_delta(groupc, s, cpu); > + deltas[s] += (u64)delta * nonidle; > } > } Yes, much clearer, thanks!