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 42996C38142 for ; Wed, 1 Feb 2023 10:01:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229612AbjBAKBE (ORCPT ); Wed, 1 Feb 2023 05:01:04 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40936 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232303AbjBAKAz (ORCPT ); Wed, 1 Feb 2023 05:00:55 -0500 Received: from 189.cn (ptr.189.cn [183.61.185.102]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 3A4AE32517 for ; Wed, 1 Feb 2023 02:00:52 -0800 (PST) HMM_SOURCE_IP: 10.64.8.31:49242.919551229 HMM_ATTACHE_NUM: 0000 HMM_SOURCE_TYPE: SMTP Received: from clientip-123.150.8.42 (unknown [10.64.8.31]) by 189.cn (HERMES) with SMTP id C7CAB1002AE; Wed, 1 Feb 2023 18:00:49 +0800 (CST) Received: from ([123.150.8.42]) by gateway-153622-dep-5cf44cb88-lf9qz with ESMTP id 2a85ec2559e34408a72b32d4ebc4d7fa for mingo@redhat.com; Wed, 01 Feb 2023 18:00:50 CST X-Transaction-ID: 2a85ec2559e34408a72b32d4ebc4d7fa X-Real-From: chensong_2000@189.cn X-Receive-IP: 123.150.8.42 X-MEDUSA-Status: 0 Sender: chensong_2000@189.cn From: Song Chen To: mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, vschneid@redhat.com Cc: linux-kernel@vger.kernel.org, Song Chen Subject: [PATCH] kernel/sched/core: adjust rt_priority accordingly when prio is changed Date: Wed, 1 Feb 2023 18:01:20 +0800 Message-Id: <1675245680-2811-1-git-send-email-chensong_2000@189.cn> X-Mailer: git-send-email 2.7.4 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When a high priority process is acquiring a rtmutex which is held by a low priority process, the latter's priority will be boosted up by calling rt_mutex_setprio->__setscheduler_prio. However, p->prio is changed but p->rt_priority is not, as a result, the equation between prio and rt_priority is broken, which is: prio = MAX_RT_PRIO - 1 - rt_priority It's confusing to the user when it calls sched_getparam, which only returns rt_priority. This patch addresses this issue by adjusting rt_priority according to the new value of prio, what's more, it also returns normal_prio for CFS processes instead of just a zero. Signed-off-by: Song Chen --- kernel/sched/core.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index bb1ee6d7bdde..1c2c4ada08cc 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -6933,14 +6933,16 @@ EXPORT_SYMBOL(default_wake_function); static void __setscheduler_prio(struct task_struct *p, int prio) { + p->prio = prio; + if (dl_prio(prio)) p->sched_class = &dl_sched_class; - else if (rt_prio(prio)) + else if (rt_prio(prio)) { + p->rt_priority = MAX_RT_PRIO - 1 - prio; p->sched_class = &rt_sched_class; + } else p->sched_class = &fair_sched_class; - - p->prio = prio; } #ifdef CONFIG_RT_MUTEXES @@ -8058,6 +8060,8 @@ SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param) if (task_has_rt_policy(p)) lp.sched_priority = p->rt_priority; + else + lp.sched_priority = normal_prio(p); rcu_read_unlock(); /* -- 2.25.1