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=-2.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 19281C35646 for ; Fri, 21 Feb 2020 15:47:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E43EF208E4 for ; Fri, 21 Feb 2020 15:47:31 +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="GLzUnTFN" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728198AbgBUPr2 (ORCPT ); Fri, 21 Feb 2020 10:47:28 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:43784 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727312AbgBUPr2 (ORCPT ); Fri, 21 Feb 2020 10:47:28 -0500 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; bh=8Rh9xF8Ip+2XcAggrOCPjsFTFtbK8F8PUpCWjSbTVZU=; b=GLzUnTFNRf5WlpOSGlBaxxK1ZC IpoU1NE44kNrImK1uh9Sef+I0YAdgnqwG1Pkhh7KtJ70ldksZ923AfJu7Uq9wzl0RzXmMxUna3bxY FOINcJWjHZV56i8v5AqYZx1o4FhLnFILkOxt/jIjvPTg++KVb3LQKGWrIaCg34EMdUegjJe4Ao8h2 6Yw618dxo9zCnjgA8G8znMLAP2JDiMaZDGeQUQbe32RmYzbdo7kelLvdyKPjMTQV/QfJPi5u4HARf E0X6deyikcdxVDGDGvg0Aaf2ppErTkox1UMU1QjthyaXNKn3O5NKgKPdv9KfySiS7Vlfv1xCIyjjo wCTf5cfA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1j5AWF-0001Zj-0o; Fri, 21 Feb 2020 15:47:11 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id D0EB1300478; Fri, 21 Feb 2020 16:45:13 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 0B17B209DB0F7; Fri, 21 Feb 2020 16:47:07 +0100 (CET) Date: Fri, 21 Feb 2020 16:47:07 +0100 From: Peter Zijlstra To: Mel Gorman Cc: ?????? , Ingo Molnar , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Luis Chamberlain , Kees Cook , Iurii Zaikin , Michal Koutn? , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, "Paul E. McKenney" , Randy Dunlap , Jonathan Corbet Subject: Re: [PATCH RESEND v8 1/2] sched/numa: introduce per-cgroup NUMA locality info Message-ID: <20200221154706.GI18400@hirez.programming.kicks-ass.net> References: <20200214151048.GL14914@hirez.programming.kicks-ass.net> <20200217115810.GA3420@suse.de> <881deb50-163e-442a-41ec-b375cc445e4d@linux.alibaba.com> <20200217141616.GB3420@suse.de> <114519ab-4e9e-996a-67b8-4f5fcecba72a@linux.alibaba.com> <20200221142010.GT3420@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200221142010.GT3420@suse.de> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Fri, Feb 21, 2020 at 02:20:10PM +0000, Mel Gorman wrote: > I fully acknowledge that this may have value for sysadmins and may be a > good enough reason to merge it for environments that typically build and > configure their own kernels. I doubt that general distributions would > enable it but that's a guess. OTOH, many sysadmins seem to 'rely' on BPF scripts and other such fancy things these days. ( of course, we have the open question on what happens when we break one of those BPF 'important' scripts ... ) My main reservation with this patch is that it exposes, to userspace, an ABI that is very hard to interpret and subject to implementation details. So while it can be disabled; people who have it enabled might suddenly complain when we change the meaning/interpretation/whatever of these magic numbers. Michael; you seem to have ignored the tracepoint / BPF angle earlier in this discussion; that is not something that could/would work for you?