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From: subhra mazumdar <subhra.mazumdar@oracle.com>
To: linux-kernel@vger.kernel.org
Cc: peterz@infradead.org, mingo@redhat.com, tglx@linutronix.de,
	steven.sistare@oracle.com, dhaval.giani@oracle.com,
	daniel.lezcano@linaro.org, vincent.guittot@linaro.org,
	viresh.kumar@linaro.org, tim.c.chen@linux.intel.com,
	mgorman@techsingularity.net, parth@linux.ibm.com,
	patrick.bellasi@arm.com
Subject: [RFC PATCH 1/9] sched,cgroup: Add interface for latency-nice
Date: Fri, 30 Aug 2019 10:49:36 -0700
Message-ID: <20190830174944.21741-2-subhra.mazumdar@oracle.com> (raw)
In-Reply-To: <20190830174944.21741-1-subhra.mazumdar@oracle.com>

Add Cgroup interface for latency-nice. Each CPU Cgroup adds a new file
"latency-nice" which is shared by all the threads in that Cgroup.

Signed-off-by: subhra mazumdar <subhra.mazumdar@oracle.com>
---
 include/linux/sched.h |  1 +
 kernel/sched/core.c   | 40 ++++++++++++++++++++++++++++++++++++++++
 kernel/sched/fair.c   |  1 +
 kernel/sched/sched.h  |  8 ++++++++
 4 files changed, 50 insertions(+)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 1183741..b4a79c3 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -631,6 +631,7 @@ struct task_struct {
 	int				static_prio;
 	int				normal_prio;
 	unsigned int			rt_priority;
+	u64				latency_nice;
 
 	const struct sched_class	*sched_class;
 	struct sched_entity		se;
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 874c427..47969bc 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5976,6 +5976,7 @@ void __init sched_init(void)
 		init_dl_rq(&rq->dl);
 #ifdef CONFIG_FAIR_GROUP_SCHED
 		root_task_group.shares = ROOT_TASK_GROUP_LOAD;
+		root_task_group.latency_nice = LATENCY_NICE_DEFAULT;
 		INIT_LIST_HEAD(&rq->leaf_cfs_rq_list);
 		rq->tmp_alone_branch = &rq->leaf_cfs_rq_list;
 		/*
@@ -6345,6 +6346,7 @@ static void sched_change_group(struct task_struct *tsk, int type)
 	 */
 	tg = container_of(task_css_check(tsk, cpu_cgrp_id, true),
 			  struct task_group, css);
+	tsk->latency_nice = tg->latency_nice;
 	tg = autogroup_task_group(tsk, tg);
 	tsk->sched_task_group = tg;
 
@@ -6812,6 +6814,34 @@ static u64 cpu_rt_period_read_uint(struct cgroup_subsys_state *css,
 }
 #endif /* CONFIG_RT_GROUP_SCHED */
 
+static u64 cpu_latency_nice_read_u64(struct cgroup_subsys_state *css,
+				     struct cftype *cft)
+{
+	struct task_group *tg = css_tg(css);
+
+	return tg->latency_nice;
+}
+
+static int cpu_latency_nice_write_u64(struct cgroup_subsys_state *css,
+				      struct cftype *cft, u64 latency_nice)
+{
+	struct task_group *tg = css_tg(css);
+	struct css_task_iter it;
+	struct task_struct *p;
+
+	if (latency_nice < LATENCY_NICE_MIN || latency_nice > LATENCY_NICE_MAX)
+		return -ERANGE;
+
+	tg->latency_nice = latency_nice;
+
+	css_task_iter_start(css, 0, &it);
+	while ((p = css_task_iter_next(&it)))
+		p->latency_nice = latency_nice;
+	css_task_iter_end(&it);
+
+	return 0;
+}
+
 static struct cftype cpu_legacy_files[] = {
 #ifdef CONFIG_FAIR_GROUP_SCHED
 	{
@@ -6848,6 +6878,11 @@ static struct cftype cpu_legacy_files[] = {
 		.write_u64 = cpu_rt_period_write_uint,
 	},
 #endif
+	{
+		.name = "latency-nice",
+		.read_u64 = cpu_latency_nice_read_u64,
+		.write_u64 = cpu_latency_nice_write_u64,
+	},
 	{ }	/* Terminate */
 };
 
@@ -7015,6 +7050,11 @@ static struct cftype cpu_files[] = {
 		.write = cpu_max_write,
 	},
 #endif
+	{
+		.name = "latency-nice",
+		.read_u64 = cpu_latency_nice_read_u64,
+		.write_u64 = cpu_latency_nice_write_u64,
+	},
 	{ }	/* terminate */
 };
 
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index f35930f..b08d00c 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -10479,6 +10479,7 @@ int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
 		goto err;
 
 	tg->shares = NICE_0_LOAD;
+	tg->latency_nice = LATENCY_NICE_DEFAULT;
 
 	init_cfs_bandwidth(tg_cfs_bandwidth(tg));
 
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index b52ed1a..365c928 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -143,6 +143,13 @@ static inline void cpu_load_update_active(struct rq *this_rq) { }
 #define NICE_0_LOAD		(1L << NICE_0_LOAD_SHIFT)
 
 /*
+ * Latency-nice default value
+ */
+#define	LATENCY_NICE_DEFAULT	5
+#define	LATENCY_NICE_MIN	1
+#define	LATENCY_NICE_MAX	100
+
+/*
  * Single value that decides SCHED_DEADLINE internal math precision.
  * 10 -> just above 1us
  * 9  -> just above 0.5us
@@ -362,6 +369,7 @@ struct cfs_bandwidth {
 /* Task group related information */
 struct task_group {
 	struct cgroup_subsys_state css;
+	u64 latency_nice;
 
 #ifdef CONFIG_FAIR_GROUP_SCHED
 	/* schedulable entities of this group on each CPU */
-- 
2.9.3


  reply index

Thread overview: 55+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-30 17:49 [RFC PATCH 0/9] Task latency-nice subhra mazumdar
2019-08-30 17:49 ` subhra mazumdar [this message]
2019-09-04 17:32   ` [RFC PATCH 1/9] sched,cgroup: Add interface for latency-nice Tim Chen
2019-09-05  6:15     ` Parth Shah
2019-09-05 10:11       ` Patrick Bellasi
2019-09-06 12:22         ` Parth Shah
2019-09-05  8:31   ` Peter Zijlstra
2019-09-05  9:45     ` Patrick Bellasi
2019-09-05 10:46       ` Peter Zijlstra
2019-09-05 11:13         ` Qais Yousef
2019-09-05 11:30           ` Peter Zijlstra
2019-09-05 11:40             ` Patrick Bellasi
2019-09-05 11:48               ` Peter Zijlstra
2019-09-05 13:32                 ` Qais Yousef
2019-09-05 11:47             ` Qais Yousef
2020-04-16  0:02               ` Joel Fernandes
2020-04-16 17:23                 ` Dietmar Eggemann
2020-04-18 16:01                   ` Joel Fernandes
2020-04-20 11:26                     ` Parth Shah
2020-04-20 19:14                       ` Joel Fernandes
2020-04-20 11:47                     ` Qais Yousef
2020-04-20 19:10                       ` Joel Fernandes
2019-09-05 11:30           ` Patrick Bellasi
2019-09-05 11:47             ` Peter Zijlstra
2019-09-05 11:18         ` Patrick Bellasi
2019-09-05 11:40           ` Peter Zijlstra
2019-09-05 11:46             ` Patrick Bellasi
2019-09-05 11:46           ` Valentin Schneider
2019-09-05 13:07             ` Patrick Bellasi
2019-09-05 14:48               ` Valentin Schneider
2019-09-06 12:45               ` Parth Shah
2019-09-06 14:13                 ` Valentin Schneider
2019-09-06 14:32                   ` Vincent Guittot
2019-09-06 17:10                   ` Parth Shah
2019-09-06 22:50                     ` Valentin Schneider
2019-09-06 12:31       ` Parth Shah
2019-09-05 10:05   ` Patrick Bellasi
2019-09-05 10:48     ` Peter Zijlstra
2019-08-30 17:49 ` [RFC PATCH 2/9] sched: add search limit as per latency-nice subhra mazumdar
2019-09-05  6:22   ` Parth Shah
2019-08-30 17:49 ` [RFC PATCH 3/9] sched: add sched feature to disable idle core search subhra mazumdar
2019-09-05 10:17   ` Patrick Bellasi
2019-09-05 22:02     ` Subhra Mazumdar
2019-08-30 17:49 ` [RFC PATCH 4/9] sched: SIS_CORE " subhra mazumdar
2019-09-05 10:19   ` Patrick Bellasi
2019-08-30 17:49 ` [RFC PATCH 5/9] sched: Define macro for number of CPUs in core subhra mazumdar
2019-08-30 17:49 ` [RFC PATCH 6/9] x86/smpboot: Optimize cpumask_weight_sibling macro for x86 subhra mazumdar
2019-08-30 17:49 ` [RFC PATCH 7/9] sched: search SMT before LLC domain subhra mazumdar
2019-09-05  9:31   ` Peter Zijlstra
2019-09-05 20:40     ` Subhra Mazumdar
2019-08-30 17:49 ` [RFC PATCH 8/9] sched: introduce per-cpu var next_cpu to track search limit subhra mazumdar
2019-08-30 17:49 ` [RFC PATCH 9/9] sched: rotate the cpu search window for better spread subhra mazumdar
2019-09-05  6:37   ` Parth Shah
2019-09-05  5:55 ` [RFC PATCH 0/9] Task latency-nice Parth Shah
2019-09-05 10:31 ` Patrick Bellasi

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