From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx0b-00069f02.pphosted.com (mx0b-00069f02.pphosted.com [205.220.177.32]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AA02E2EAB92 for ; Thu, 24 Jul 2025 16:16:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=205.220.177.32 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753373807; cv=none; b=mDk27Y3hlblCb0GRBRhnPqpkqtZ7A6OcB3AnOkJKg9/J5Tm4WEbV5crvSLv4anwWL6UzaTPiqyK5bDkHmUVtw8c8ImysKQmbw3Ge4Q0g8mzzKlswV5bzHb5ekWNHU6hsa+gYlZRvZaBUhR2tG2UZqqcSPITOjPewVSJdUdKUuBU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753373807; c=relaxed/simple; bh=WzDMjhtrij63D1Wchw5KY7l5YrcHibk05bu7jqh+tSc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Y6vgScxBfds4o9PcsQjHfvDohCk1cCIQPX1fyGpMuHridmRRy1aWzrFVmNYh2Fg50010nH/BOR7mq7GKPFVxoRwEvlQCs0CmsuSbijmoYQhzBSBgAtaB8CZ2vbaQJGCMOKEPENk26f4xjlH+dCUoxnvNU5bFUkzYIG0xEg3S1Fc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=oracle.com; spf=pass smtp.mailfrom=oracle.com; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b=an565Mhy; arc=none smtp.client-ip=205.220.177.32 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=oracle.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=oracle.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="an565Mhy" Received: from pps.filterd (m0333520.ppops.net [127.0.0.1]) by mx0b-00069f02.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 56ODRSlB013384; Thu, 24 Jul 2025 16:16:33 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=cc :content-transfer-encoding:date:from:in-reply-to:message-id :mime-version:references:subject:to; s=corp-2025-04-25; bh=EExTV jVes3B45GrPCTCkse+AO/P8tSAm6iyo/WLjQKI=; b=an565MhygqCiuAVKd+AhC WPRh6XxhgzUKr21ezgakRalSjpVf/4BgFDo2XkkFsi7EKWz2x5cbo5EQH9KAHbjP pN8yMYAIj1zAStLuPYN/J1UGPXwEy5o/DYDRSgF2hRz2eq9iOM8PhIHoFGip+xqA V1hbC/FVEXVLuDrG/F1w76C2AbpHgOYF/mg8FJ0zFMea+FUFpHmCERfKqqwDFoJC lGE+8mPDKPvzkRG5T/+RjEumNDSfv0KAwDaDpEwCVT5PMZDgB7IUctgT19OaAeLC XX2un6hbICfFy/MPTytlSfvH+eEJ2aJhX/n/BC2Q1tj3Ykk7HvLrHCscrpO68J9G w== Received: from iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com (iadpaimrmta01.appoci.oracle.com [130.35.100.223]) by mx0b-00069f02.pphosted.com (PPS) with ESMTPS id 48057r24ky-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 24 Jul 2025 16:16:32 +0000 (GMT) Received: from pps.filterd (iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com [127.0.0.1]) by iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com (8.18.1.2/8.18.1.2) with ESMTP id 56OFRZwU014611; Thu, 24 Jul 2025 16:16:32 GMT Received: from pps.reinject (localhost [127.0.0.1]) by iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com (PPS) with ESMTPS id 4801tjcfsm-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Thu, 24 Jul 2025 16:16:32 +0000 Received: from iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com (iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com [127.0.0.1]) by pps.reinject (8.17.1.5/8.17.1.5) with ESMTP id 56OGGRNY034466; Thu, 24 Jul 2025 16:16:31 GMT Received: from psang-work.osdevelopmeniad.oraclevcn.com (psang-work.allregionaliads.osdevelopmeniad.oraclevcn.com [100.100.253.35]) by iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com (PPS) with ESMTPS id 4801tjcfne-10 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Thu, 24 Jul 2025 16:16:31 +0000 From: Prakash Sangappa To: linux-kernel@vger.kernel.org Cc: peterz@infradead.org, rostedt@goodmis.org, mathieu.desnoyers@efficios.com, tglx@linutronix.de, bigeasy@linutronix.de, kprateek.nayak@amd.com, vineethr@linux.ibm.com, prakash.sangappa@oracle.com Subject: [PATCH V7 09/11] sched: Add nodelay scheduling Date: Thu, 24 Jul 2025 16:16:23 +0000 Message-ID: <20250724161625.2360309-10-prakash.sangappa@oracle.com> X-Mailer: git-send-email 2.43.5 In-Reply-To: <20250724161625.2360309-1-prakash.sangappa@oracle.com> References: <20250724161625.2360309-1-prakash.sangappa@oracle.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1099,Hydra:6.1.9,FMLib:17.12.80.40 definitions=2025-07-24_02,2025-07-24_01,2025-03-28_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 adultscore=0 bulkscore=0 suspectscore=0 mlxscore=0 phishscore=0 mlxlogscore=999 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2505160000 definitions=main-2507240123 X-Authority-Analysis: v=2.4 cv=MNRgmNZl c=1 sm=1 tr=0 ts=68825c60 b=1 cx=c_pps a=zPCbziy225d3KhSqZt3L1A==:117 a=zPCbziy225d3KhSqZt3L1A==:17 a=Wb1JkmetP80A:10 a=yPCof4ZbAAAA:8 a=wwdHoo5uXkV_8ci4LmkA:9 cc=ntf awl=host:12061 X-Proofpoint-ORIG-GUID: 1KeYoU0hqspgGoK6MYEYfpxMsLFhxEqR X-Proofpoint-GUID: 1KeYoU0hqspgGoK6MYEYfpxMsLFhxEqR X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUwNzI0MDEyMyBTYWx0ZWRfXwS4b//ccepKx aWj9p6oA3dmsNZTaov85hbR4z2gFaVETK/S1GOR+9gsJm/stlOG7oBQJo83KR2sxaUOaMIDVvFB 8tLQVXbYtt+rCM1PUsVmucE/6dlCi621kJRh53uN4VSYyzg/OVOPy05CvgG4zq4iOURSvlDav7M f4JH1QaFZ4SizuBfB3CgH5x779tTAQ6FKSOsQ1hf3jsLNpBXLPy3AFND1pL3GcnLgVGamsW8Lvv zZCg2wFYrGjACMbMuXdZGm1ATwArOd2D37mbGoltMq6REtAiCcR68GcvyyLDoJ9l1+ZFKtVnzg0 PLx+SCAbzFlPq1ptyeGuR3xUqbMobCepua+GOq9iy1pG7qbw4v5Ol5GQFJJkjB5p4l/qvs+NsBO KvMKy4hmPxVPtxMzAuOFVrRqsMPL2T7O1yBtwbxAn6I8L3J0QkEI4d//jvFz5Xa5diXXF5+a Realtime threads that are sensitive can indicate not to be delayed by a thread running on th cpu, that has requested scheduler time slice extension. Suggested-by: Thomas Gleixner Signed-off-by: Prakash Sangappa --- init/Kconfig | 2 +- kernel/Kconfig.preempt | 3 +++ kernel/sched/core.c | 14 ++++++++++++++ kernel/sched/rt.c | 10 +++++----- kernel/sched/sched.h | 1 + 5 files changed, 24 insertions(+), 6 deletions(-) diff --git a/init/Kconfig b/init/Kconfig index 3005abab77cf..119448f0b9e1 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1132,7 +1132,7 @@ config SCHED_MM_CID config RSEQ_RESCHED_DELAY def_bool y - depends on SMP && RSEQ && SCHED_HRTICK + depends on SMP && RSEQ && SCHED_HRTICK && ARCH_HAS_PREEMPT_NODELAY help This feature enables a thread to request extending its time slice on the cpu by delaying preemption. diff --git a/kernel/Kconfig.preempt b/kernel/Kconfig.preempt index 54ea59ff8fbe..96809d8d8bcb 100644 --- a/kernel/Kconfig.preempt +++ b/kernel/Kconfig.preempt @@ -14,6 +14,9 @@ config PREEMPT_BUILD config ARCH_HAS_PREEMPT_LAZY bool +config ARCH_HAS_PREEMPT_NODELAY + bool + choice prompt "Preemption Model" default PREEMPT_NONE diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 035eec8911c2..e9be8a6b8851 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1185,6 +1185,20 @@ void resched_curr_lazy(struct rq *rq) __resched_curr(rq, get_lazy_tif_bit()); } +#ifdef CONFIG_RSEQ_RESCHED_DELAY +void resched_curr_nodelay(struct rq *rq, struct task_struct *p) +{ + int tif; + tif = p->sched_nodelay ? TIF_NEED_RESCHED_NODELAY : TIF_NEED_RESCHED; + __resched_curr(rq, tif); +} +#else +void resched_curr_nodelay(struct rq *rq, struct task_struct *p) +{ + __resched_curr(rq, TIF_NEED_RESCHED); +} +#endif + void resched_cpu(int cpu) { struct rq *rq = cpu_rq(cpu); diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index e40422c37033..1beae971799e 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -1027,7 +1027,7 @@ static void update_curr_rt(struct rq *rq) rt_rq->rt_time += delta_exec; exceeded = sched_rt_runtime_exceeded(rt_rq); if (exceeded) - resched_curr(rq); + resched_curr_nodelay(rq, rq->curr); raw_spin_unlock(&rt_rq->rt_runtime_lock); if (exceeded) do_start_rt_bandwidth(sched_rt_bandwidth(rt_rq)); @@ -1634,7 +1634,7 @@ static void check_preempt_equal_prio(struct rq *rq, struct task_struct *p) * to try and push the current task away: */ requeue_task_rt(rq, p, 1); - resched_curr(rq); + resched_curr_nodelay(rq, p); } static int balance_rt(struct rq *rq, struct task_struct *p, struct rq_flags *rf) @@ -1663,7 +1663,7 @@ static void wakeup_preempt_rt(struct rq *rq, struct task_struct *p, int flags) struct task_struct *donor = rq->donor; if (p->prio < donor->prio) { - resched_curr(rq); + resched_curr_nodelay(rq, p); return; } @@ -1999,7 +1999,7 @@ static int push_rt_task(struct rq *rq, bool pull) * just reschedule current. */ if (unlikely(next_task->prio < rq->donor->prio)) { - resched_curr(rq); + resched_curr_nodelay(rq, next_task); return 0; } @@ -2087,7 +2087,7 @@ static int push_rt_task(struct rq *rq, bool pull) } move_queued_task_locked(rq, lowest_rq, next_task); - resched_curr(lowest_rq); + resched_curr_nodelay(lowest_rq, next_task); ret = 1; double_unlock_balance(rq, lowest_rq); diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index f213f9e68aa6..b81354dfed3c 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -2698,6 +2698,7 @@ extern void init_sched_fair_class(void); extern void resched_curr(struct rq *rq); extern void resched_curr_lazy(struct rq *rq); extern void resched_cpu(int cpu); +extern void resched_curr_nodelay(struct rq *rq, struct task_struct *p); extern void init_rt_bandwidth(struct rt_bandwidth *rt_b, u64 period, u64 runtime); extern bool sched_rt_bandwidth_account(struct rt_rq *rt_rq); -- 2.43.5