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=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 955BAC4320E for ; Thu, 26 Aug 2021 10:00:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7479A610D2 for ; Thu, 26 Aug 2021 10:00:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241112AbhHZKBT (ORCPT ); Thu, 26 Aug 2021 06:01:19 -0400 Received: from mail.kernel.org ([198.145.29.99]:34894 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241085AbhHZKBT (ORCPT ); Thu, 26 Aug 2021 06:01:19 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 60C0A610D0; Thu, 26 Aug 2021 10:00:28 +0000 (UTC) Date: Thu, 26 Aug 2021 12:00:25 +0200 From: Christian Brauner To: Eugene Syromiatnikov , "Peter Zijlstra (Intel)" Cc: "Joel Fernandes (Google)" , Chris Hyser , Josh Don , Ingo Molnar , Vincent Guittot , Valentin Schneider , Mel Gorman , linux-kernel@vger.kernel.org, Thomas Gleixner , "Dmitry V. Levin" , linux-doc@vger.kernel.org, linux-api@vger.kernel.org, Jonathan Corbet Subject: Re: [PATCH v4] uapi/linux/prctl: provide macro definitions for the PR_SCHED_CORE type argument Message-ID: <20210826100025.pdakvmg24gomnuk5@wittgenstein> References: <20210825170613.GA3884@asgard.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20210825170613.GA3884@asgard.redhat.com> Precedence: bulk List-ID: X-Mailing-List: linux-api@vger.kernel.org On Wed, Aug 25, 2021 at 07:06:13PM +0200, Eugene Syromiatnikov wrote: > Commit 7ac592aa35a684ff ("sched: prctl() core-scheduling interface") > made use of enum pid_type in prctl's arg4; this type and the associated > enumeration definitions are not exposed to userspace. Christian > has suggested to provide additional macro definitions that convey > the meaning of the type argument more in alignment with its actual > usage, and this patch does exactly that. > > Suggested-by: Christian Brauner > Complements: 7ac592aa35a684ff ("sched: prctl() core-scheduling interface") > Signed-off-by: Eugene Syromiatnikov > --- I mean, I proposed the names so I'm ok with them. :) Acked-by: Christian Brauner Peter et al. are you ok with this and do the names make sense to you? Christian > v4: > - Rewritten in accordance with Christian Brauner's suggestion to provide > macro definitions that are explicitly tailored for the prctl op. > > v3: https://lore.kernel.org/lkml/20210807120905.GA14706@asgard.redhat.com/ > - Fixed header guard macro: s/_UAPI_LINUX_PID_H/_UAPI_LINUX_PIDTYPE_H/, > as noted by Dmitry Levin. > > v2: https://lore.kernel.org/lkml/20210807104800.GA22620@asgard.redhat.com/ > - Header file is renamed from pid.h to pidtype.h to avoid collisions > with include/linux/pid.h when included from uapi headers; > - The enum type has renamed from __kernel_pid_type to __kernel_pidtype > to avoid possible confusion with __kernel_pid_t. > > v1: https://lore.kernel.org/lkml/20210807010123.GA5174@asgard.redhat.com/ > --- > Documentation/admin-guide/hw-vuln/core-scheduling.rst | 5 +++-- > include/uapi/linux/prctl.h | 3 +++ > kernel/sched/core_sched.c | 4 ++++ > 3 files changed, 10 insertions(+), 2 deletions(-) > > diff --git a/Documentation/admin-guide/hw-vuln/core-scheduling.rst b/Documentation/admin-guide/hw-vuln/core-scheduling.rst > index 7b410ae..9a65fed 100644 > --- a/Documentation/admin-guide/hw-vuln/core-scheduling.rst > +++ b/Documentation/admin-guide/hw-vuln/core-scheduling.rst > @@ -61,8 +61,9 @@ arg3: > ``pid`` of the task for which the operation applies. > > arg4: > - ``pid_type`` for which the operation applies. It is of type ``enum pid_type``. > - For example, if arg4 is ``PIDTYPE_TGID``, then the operation of this command > + ``pid_type`` for which the operation applies. It is one of > + ``PR_SCHED_CORE_SCOPE_``-prefixed macro constants. For example, if arg4 > + is ``PR_SCHED_CORE_SCOPE_THREAD_GROUP``, then the operation of this command > will be performed for all tasks in the task group of ``pid``. > > arg5: > diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h > index 967d9c5..644a3b4 100644 > --- a/include/uapi/linux/prctl.h > +++ b/include/uapi/linux/prctl.h > @@ -266,5 +266,8 @@ struct prctl_mm_map { > # define PR_SCHED_CORE_SHARE_TO 2 /* push core_sched cookie to pid */ > # define PR_SCHED_CORE_SHARE_FROM 3 /* pull core_sched cookie to pid */ > # define PR_SCHED_CORE_MAX 4 > +# define PR_SCHED_CORE_SCOPE_THREAD 0 > +# define PR_SCHED_CORE_SCOPE_THREAD_GROUP 1 > +# define PR_SCHED_CORE_SCOPE_PROCESS_GROUP 2 > > #endif /* _LINUX_PRCTL_H */ > diff --git a/kernel/sched/core_sched.c b/kernel/sched/core_sched.c > index 9a80e9a..20f6409 100644 > --- a/kernel/sched/core_sched.c > +++ b/kernel/sched/core_sched.c > @@ -134,6 +134,10 @@ int sched_core_share_pid(unsigned int cmd, pid_t pid, enum pid_type type, > if (!static_branch_likely(&sched_smt_present)) > return -ENODEV; > > + BUILD_BUG_ON(PR_SCHED_CORE_SCOPE_THREAD != PIDTYPE_PID); > + BUILD_BUG_ON(PR_SCHED_CORE_SCOPE_THREAD_GROUP != PIDTYPE_TGID); > + BUILD_BUG_ON(PR_SCHED_CORE_SCOPE_PROCESS_GROUP != PIDTYPE_PGID); > + > if (type > PIDTYPE_PGID || cmd >= PR_SCHED_CORE_MAX || pid < 0 || > (cmd != PR_SCHED_CORE_GET && uaddr)) > return -EINVAL; > -- > 2.1.4 >