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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 30F56C433F5 for ; Thu, 6 Oct 2022 21:31:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232350AbiJFVb2 (ORCPT ); Thu, 6 Oct 2022 17:31:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42082 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229567AbiJFVb0 (ORCPT ); Thu, 6 Oct 2022 17:31:26 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 730B7C6979 for ; Thu, 6 Oct 2022 14:31:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1665091884; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=mQPGA0km9mF9Y0hk7+wuSbQLv4IDl43JAA6JVzQkHnY=; b=JHu/VBuEfgM0XjNssEK9qtDghBvOnjhAySjp4IoPpXX6O/AtnSpynV5RuoSEkfrldoNlKu +IbcA+INpftHQE5nJoaqFYsY17bJzqVgHWNyujwOaMLWhGPbssKVwFCKrqFqjcMfpg2u6s /MfXCB6VnF7RIUDQCQOUNue6Zw2KYxA= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-255-Xro4KT9JNLiceytZRHq0Ag-1; Thu, 06 Oct 2022 17:31:13 -0400 X-MC-Unique: Xro4KT9JNLiceytZRHq0Ag-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 799C781B081; Thu, 6 Oct 2022 21:31:12 +0000 (UTC) Received: from [10.22.8.198] (unknown [10.22.8.198]) by smtp.corp.redhat.com (Postfix) with ESMTP id 6ADA01402BDA; Thu, 6 Oct 2022 21:31:11 +0000 (UTC) Message-ID: <9777b2f5-2dae-679e-4fe6-f5019ac7a18f@redhat.com> Date: Thu, 6 Oct 2022 17:31:11 -0400 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.12.0 Subject: Re: [PATCH v10 0/5] sched: Persistent user requested affinity Content-Language: en-US To: Peter Zijlstra Cc: linux-kernel@vger.kernel.org, Linus Torvalds , Lai Jiangshan , Juri Lelli , Ingo Molnar , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Daniel Bristot de Oliveira , Valentin Schneider , Tejun Heo , Zefan Li , Johannes Weiner , Will Deacon References: <20220922180041.1768141-1-longman@redhat.com> From: Waiman Long In-Reply-To: <20220922180041.1768141-1-longman@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 3.1 on 10.11.54.7 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 9/22/22 14:00, Waiman Long wrote: > v10: > - Squash patches 4, 5 & 6 together into a single patch as suggested > by PeterZ. > > v9: > - Fix non-SMP config build errors in patch 4 reported by kernel test > robot. > - Disable user_cpus_ptr masking also when any of the SCA_MIGRATE_* > flags are set. > > v8: > - Add patches "sched: Introduce affinity_context structure" and > "sched: Always clear user_cpus_ptr in do_set_cpus_allowed()" as > suggested by PeterZ. > - Better handle cpuset and sched_setaffinity() race in patch 5. > > v7: > - Make changes recommended by Peter such as making scratch_mask > allocation earlier and using percpu variable to pass information. > > The user_cpus_ptr field is added by commit b90ca8badbd1 ("sched: > Introduce task_struct::user_cpus_ptr to track requested affinity") > which uses it narrowly to allow keeping cpus affinity intact with > asymmetric cpu setup. > > This patchset extends user_cpus_ptr to store user requested cpus affinity > via the sched_setaffinity() API. With that information available, it will > enable cpuset and other callers of set_cpus_allowed_ptr() like hotplug > to keep cpus afinity as close to what the user wants as possible within > the cpu list constraint of the current cpuset. Otherwise some change > to the cpuset hierarchy or a hotplug event may reset the cpumask of > the tasks in the affected cpusets to the default cpuset value even if > those tasks have cpus affinity explicitly set by the users before. > > It also means that once sched_setaffinity() is called successfully, > user_cpus_ptr will remain allocated until the task exits except in some > rare circumstances. > > Waiman Long (5): > sched: Add __releases annotations to affine_move_task() > sched: Use user_cpus_ptr for saving user provided cpumask in > sched_setaffinity() > sched: Enforce user requested affinity > sched: Handle set_cpus_allowed_ptr(), sched_setaffinity() & other > races > sched: Always clear user_cpus_ptr in do_set_cpus_allowed() > > kernel/sched/core.c | 231 +++++++++++++++++++++++++--------------- > kernel/sched/deadline.c | 7 +- > kernel/sched/sched.h | 22 +++- > 3 files changed, 169 insertions(+), 91 deletions(-) > Peter, do you have any further suggestion on how to improve this series? Thanks, Longman