From patchwork Wed May 15 09:44:48 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Patrick Bellasi X-Patchwork-Id: 10944473 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 8B39D1390 for ; Wed, 15 May 2019 09:45:51 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7A65628740 for ; Wed, 15 May 2019 09:45:51 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 6DF8F2882E; Wed, 15 May 2019 09:45:51 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0906C28740 for ; Wed, 15 May 2019 09:45:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726201AbfEOJpt (ORCPT ); Wed, 15 May 2019 05:45:49 -0400 Received: from foss.arm.com ([217.140.101.70]:39294 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726501AbfEOJps (ORCPT ); Wed, 15 May 2019 05:45:48 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 52674A78; Wed, 15 May 2019 02:45:48 -0700 (PDT) Received: from e110439-lin.cambridge.arm.com (e110439-lin.cambridge.arm.com [10.1.194.43]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 37C443F703; Wed, 15 May 2019 02:45:45 -0700 (PDT) From: Patrick Bellasi To: linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, linux-api@vger.kernel.org Cc: Ingo Molnar , Peter Zijlstra , Tejun Heo , "Rafael J . Wysocki" , Vincent Guittot , Viresh Kumar , Paul Turner , Quentin Perret , Dietmar Eggemann , Morten Rasmussen , Juri Lelli , Todd Kjos , Joel Fernandes , Steve Muckle , Suren Baghdasaryan Subject: [PATCH v9 05/16] sched/core: Allow sched_setattr() to use the current policy Date: Wed, 15 May 2019 10:44:48 +0100 Message-Id: <20190515094459.10317-6-patrick.bellasi@arm.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190515094459.10317-1-patrick.bellasi@arm.com> References: <20190515094459.10317-1-patrick.bellasi@arm.com> MIME-Version: 1.0 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The sched_setattr() syscall mandates that a policy is always specified. This requires to always know which policy a task will have when attributes are configured and this makes it impossible to add more generic task attributes valid across different scheduling policies. Reading the policy before setting generic tasks attributes is racy since we cannot be sure it is not changed concurrently. Introduce the required support to change generic task attributes without affecting the current task policy. This is done by adding an attribute flag (SCHED_FLAG_KEEP_POLICY) to enforce the usage of the current policy. Add support for the SETPARAM_POLICY policy, which is already used by the sched_setparam() POSIX syscall, to the sched_setattr() non-POSIX syscall. Signed-off-by: Patrick Bellasi Cc: Ingo Molnar Cc: Peter Zijlstra --- Changes in v9: Message-ID: <20190509145901.um7rrsslg7de4blf@e110439-lin> - get rid of not necessary SCHED_POLICY_MAX define - update sched_setattr() syscall to just force the current policy on SCHED_FLAG_KEEP_POLICY --- include/uapi/linux/sched.h | 4 +++- kernel/sched/core.c | 2 ++ 2 files changed, 5 insertions(+), 1 deletion(-) diff --git a/include/uapi/linux/sched.h b/include/uapi/linux/sched.h index 22627f80063e..261b6e43846c 100644 --- a/include/uapi/linux/sched.h +++ b/include/uapi/linux/sched.h @@ -50,9 +50,11 @@ #define SCHED_FLAG_RESET_ON_FORK 0x01 #define SCHED_FLAG_RECLAIM 0x02 #define SCHED_FLAG_DL_OVERRUN 0x04 +#define SCHED_FLAG_KEEP_POLICY 0x08 #define SCHED_FLAG_ALL (SCHED_FLAG_RESET_ON_FORK | \ SCHED_FLAG_RECLAIM | \ - SCHED_FLAG_DL_OVERRUN) + SCHED_FLAG_DL_OVERRUN | \ + SCHED_FLAG_KEEP_POLICY) #endif /* _UAPI_LINUX_SCHED_H */ diff --git a/kernel/sched/core.c b/kernel/sched/core.c index dac73a5959b6..43b29b2efa4c 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -4863,6 +4863,8 @@ SYSCALL_DEFINE3(sched_setattr, pid_t, pid, struct sched_attr __user *, uattr, if ((int)attr.sched_policy < 0) return -EINVAL; + if (attr.sched_flags & SCHED_FLAG_KEEP_POLICY) + attr.sched_policy = SETPARAM_POLICY; rcu_read_lock(); retval = -ESRCH;