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=-13.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL 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 06DBCC433B4 for ; Wed, 12 May 2021 20:46:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CDB7061221 for ; Wed, 12 May 2021 20:46:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1387930AbhELUlD (ORCPT ); Wed, 12 May 2021 16:41:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55502 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1386849AbhELUWY (ORCPT ); Wed, 12 May 2021 16:22:24 -0400 Received: from mail-qt1-x829.google.com (mail-qt1-x829.google.com [IPv6:2607:f8b0:4864:20::829]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3C814C061353 for ; Wed, 12 May 2021 13:20:15 -0700 (PDT) Received: by mail-qt1-x829.google.com with SMTP id j19so18198734qtp.7 for ; Wed, 12 May 2021 13:20:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=dUIJstx/27xJVJz6QvCNOVh0gIQL6FYmLOnlZbT26JY=; b=gHtfhdTydYQykUTziTudHgN3fY5eRaL0TRbmCbpE/HyutC8I7eMRHymRr0f/F94N/q mDhKFMgyHunn8V1UvTp453K69fOaVBWqmCxPSLAyvQBRnujT00a2RCjMQqcord9iYI9Q DgikAWPXqoLdPCm2cv9GuFTKyablXEAcS6dUKsUy8GWTFTzqtR+lFSIXcchBFuJDQTVI ee8VsLYjNhW5H51afxzp73EcbEhAQcRk4mzK5s5t9C3K0XzrgmEseLbPZyS+KQLhr9bY BjzOCT1RSNrq+EE6oo05Z8m91yxppvW0iTyMG477mdxXC9iH8S5l7W/m/r4E2bupSKHU ER9g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=dUIJstx/27xJVJz6QvCNOVh0gIQL6FYmLOnlZbT26JY=; b=t/OUEkhlXdB9RBa2dLt8BT35jCXzaKHrLUygSqqCa5DdhA1GFdga/VYNYcjWR1c1uP LZaChGducifSe9ULaxXDoY0/6inQt2UdRp3DqP2dvVAFdtsTZyZEEc5kaMsU5Zp1aoXf UH0fQIWrZhQewQp3U49RpKHlgPFgjXw2xMAzhmfM8IXGb8Cn3RSpC8mFRYH1eD9L4T8q X17qat7PFtzvJKwLXWDL/zCfrflEkfQq1BVHXCmkP9el6cTo/Ggy7NlrpvY8WFaMECw8 WqZZNngRssFBN9N5BFn+CbpMjzBPiyoY15IJbJHRPRdjc3Pk/6ixGqU9CuY8jXD37Myq g5VQ== X-Gm-Message-State: AOAM533Dm7Qb1vVpSe6pyJHkMNgfWt6P+PkIyoMCoQ/FUQ9aBqV4UA4X kwMQal3Yr0lxbX9Zf1tqF4CuOz6FONZof6bu3dAN0Q== X-Google-Smtp-Source: ABdhPJxtMXLhHYJuWiY0OsXg1Vwzw0RC9z7My1doZmIhPaMmNZmmtY48fMAiP4xOY5Y5j5Fi2FbfcrWCKiwFMmKBvys= X-Received: by 2002:a05:622a:114:: with SMTP id u20mr34729020qtw.317.1620850814080; Wed, 12 May 2021 13:20:14 -0700 (PDT) MIME-Version: 1.0 References: <20210422120459.447350175@infradead.org> <20210422123308.980003687@infradead.org> <3dbce4ff-44ed-73ca-2ea1-97b126dd664e@oracle.com> <2b4ae2b4-62e5-96be-ddae-b261139842c1@oracle.com> In-Reply-To: From: Josh Don Date: Wed, 12 May 2021 13:20:02 -0700 Message-ID: Subject: Re: [PATCH 17/19] sched: Inherit task cookie on fork() To: Peter Zijlstra Cc: Chris Hyser , Joel Fernandes , Ingo Molnar , Vincent Guittot , Valentin Schneider , Mel Gorman , LKML , Thomas Glexiner Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 12, 2021 at 2:05 AM Peter Zijlstra wrote: > Right, I need a Champion that actually cares about cgroups and has > use-cases to go argue with TJ on this. I've proposed code that I think > has sane semantics, but I'm not in a position to argue for it, given I > think a world without cgroups is a better world :-))) Not sure if Tejun has any thoughts on http://lkml.kernel.org/r/CABk29NtahuW6UERvRdK5v8My_MfPsoESDKXUjGdvaQcHOJEMvg@mail.gmail.com. We're looking at using the prctl interface with one of our main internal users of core scheduling. As an example, suppose we have a management process that wants to make tasks A and B share a cookie: - Spawn a new thread m, which then does the following, and exits. - PR_SCHED_CORE_CREATE for just its own PID - PR_SCHED_CORE_SHARE_TO A - PR_SCHED_CORE_SHARE_TO B That seems to work ok; I'll follow up if there are any pain points that aren't easily addressed with the prctl interface.