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=-1.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_PASS 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 14C35C43381 for ; Wed, 20 Feb 2019 18:45:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DED2120859 for ; Wed, 20 Feb 2019 18:45:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="DUnKh8UH" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727008AbfBTSpt (ORCPT ); Wed, 20 Feb 2019 13:45:49 -0500 Received: from aserp2130.oracle.com ([141.146.126.79]:48572 "EHLO aserp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725877AbfBTSpt (ORCPT ); Wed, 20 Feb 2019 13:45:49 -0500 Received: from pps.filterd (aserp2130.oracle.com [127.0.0.1]) by aserp2130.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x1KIYINx006799; Wed, 20 Feb 2019 18:45:24 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=subject : to : cc : references : from : message-id : date : mime-version : in-reply-to : content-type : content-transfer-encoding; s=corp-2018-07-02; bh=6QdK9boB/GprqfvOOeLbljG89BjD1NPQ8GkF2zwBFnw=; b=DUnKh8UH2y8hARzAXu7lVsNV6Zh3/QVkPUwULHEDg0xrLUWgDGVXRVFrNm0ZaYgTlIzp C7Db1sPEROEe1yNLa7DZMIdiTBKZkONPjoAph59Q12GQYjNuIsWcotJQJPou7x+UFI0X jUr40p6Z96AWLxv22Pfu8wwBuWKBLJHUJEcm6tedln7B8fRugHXVMMV0TExrI6C1nfeF sPfVhHdpO4r954lFVD6OIti4NiP9IJ/Tznhw0ZG6pIsEJYe9h29Y+RQFd0wZp9M8j2ur wsakQNqU/NpuJTh0nx9CrKV4w46L3F/r+OLVphQtJd3GDdOzgColNcP+S2ZU711EW5Mc IQ== Received: from userv0021.oracle.com (userv0021.oracle.com [156.151.31.71]) by aserp2130.oracle.com with ESMTP id 2qp81ebky1-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 20 Feb 2019 18:45:24 +0000 Received: from aserv0121.oracle.com (aserv0121.oracle.com [141.146.126.235]) by userv0021.oracle.com (8.14.4/8.14.4) with ESMTP id x1KIjH9R013633 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 20 Feb 2019 18:45:18 GMT Received: from abhmp0015.oracle.com (abhmp0015.oracle.com [141.146.116.21]) by aserv0121.oracle.com (8.14.4/8.13.8) with ESMTP id x1KIjHEB023687; Wed, 20 Feb 2019 18:45:17 GMT Received: from [10.132.91.175] (/10.132.91.175) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 20 Feb 2019 10:45:17 -0800 Subject: Re: [RFC][PATCH 00/16] sched: Core scheduling To: Peter Zijlstra , Greg Kerr Cc: mingo@kernel.org, tglx@linutronix.de, Paul Turner , tim.c.chen@linux.intel.com, torvalds@linux-foundation.org, linux-kernel@vger.kernel.org, fweisbec@gmail.com, keescook@chromium.org References: <20190218165620.383905466@infradead.org> <20190220094255.GE32494@hirez.programming.kicks-ass.net> From: Subhra Mazumdar Message-ID: Date: Wed, 20 Feb 2019 10:43:09 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: <20190220094255.GE32494@hirez.programming.kicks-ass.net> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9173 signatures=668683 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1011 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1902200129 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2/20/19 1:42 AM, Peter Zijlstra wrote: > A: Because it messes up the order in which people normally read text. > Q: Why is top-posting such a bad thing? > A: Top-posting. > Q: What is the most annoying thing in e-mail? > > On Tue, Feb 19, 2019 at 02:07:01PM -0800, Greg Kerr wrote: >> Thanks for posting this patchset Peter. Based on the patch titled, "sched: A >> quick and dirty cgroup tagging interface," I believe cgroups are used to >> define co-scheduling groups in this implementation. >> >> Chrome OS engineers (kerrnel@google.com, mpdenton@google.com, and >> palmer@google.com) are considering an interface that is usable by unprivileged >> userspace apps. cgroups are a global resource that require privileged access. >> Have you considered an interface that is akin to namespaces? Consider the >> following strawperson API proposal (I understand prctl() is generally >> used for process >> specific actions, so we aren't married to using prctl()): > I don't think we're anywhere near the point where I care about > interfaces with this stuff. > > Interfaces are a trivial but tedious matter once the rest works to > satisfaction. > > As it happens; there is actually a bug in that very cgroup patch that > can cause undesired scheduling. Try spotting and fixing that. > > Another question is if we want to be L1TF complete (and how strict) or > not, and if so, build the missing pieces (for instance we currently > don't kick siblings on IRQ/trap/exception entry -- and yes that's nasty > and horrible code and missing for that reason). I remember asking Paul about this and he mentioned he has a Address Space Isolation proposal to cover this. So it seems this is out of scope of core scheduling? > > So first; does this provide what we need? If that's sorted we can > bike-shed on uapi/abi.