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Re: [PATCH] Hookup group-scheduler with task container infrastructure [message #19998] Mon, 10 September 2007 17:22 Go to next message
akpm is currently offline  akpm
Messages: 224
Registered: March 2007
Senior Member
On Mon, 10 Sep 2007 22:53:34 +0530 Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> wrote:

> On Mon, Sep 10, 2007 at 07:05:00PM +0200, Jan Engelhardt wrote:
> > On Sep 10 2007 22:40, Srivatsa Vaddagiri wrote:
> > >+#ifdef CONFIG_FAIR_GROUP_SCHED
> > >+SUBSYS(cpuctlr)
> > >+#endif
> > 
> > cpuctl, cpuctrl, cpu_controller?
> 
> *shrug* .. I used "cpuctlr" to mean "CPU Controller". Any other short names
> would do. From your list, cpuctl or cpuctrl both qualifies IMO!
> 
> Unless folks have strong objection to it, I prefer "cptctlr", the way it is.
> 

objection ;)  "cpuctlr" isn't memorable.  Kernel code is write-rarely,
read-often.  "cpu_controller", please.  The extra typing is worth it ;)
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Re: Re: [PATCH] Hookup group-scheduler with task container infrastructure [message #20004 is a reply to message #19998] Mon, 10 September 2007 18:38 Go to previous messageGo to next message
Paul Menage is currently offline  Paul Menage
Messages: 642
Registered: September 2006
Senior Member
On 9/10/07, Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> wrote:
>
> Unless folks have strong objection to it, I prefer "cptctlr", the way it is.
>

By definition any container (about to be renamed control group)
subsystem is some kind of "controller" so that bit seems a bit
redundant.

Any reason not to just call it "cpu" or "cpu_sched"

Paul
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Re: [PATCH] Hookup group-scheduler with task container infrastructure [message #20021 is a reply to message #19998] Mon, 10 September 2007 17:41 Go to previous messageGo to next message
Jan Engelhardt is currently offline  Jan Engelhardt
Messages: 18
Registered: August 2006
Junior Member
On Sep 10 2007 10:22, Andrew Morton wrote:
>> Unless folks have strong objection to it, I prefer "cptctlr", the way it is.
>
>Kernel code is write-rarely, read-often.

I think you mean __read_mostly. :-)




	Jan
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Re: [PATCH] Hookup group-scheduler with task container infrastructure [message #20031 is a reply to message #19998] Mon, 10 September 2007 17:46 Go to previous messageGo to next message
Srivatsa Vaddagiri is currently offline  Srivatsa Vaddagiri
Messages: 241
Registered: August 2006
Senior Member
On Mon, Sep 10, 2007 at 10:22:59AM -0700, Andrew Morton wrote:
> objection ;)  "cpuctlr" isn't memorable.  Kernel code is write-rarely,
> read-often.  "cpu_controller", please.  The extra typing is worth it ;)

Ok! Here's the modified patch (against 2.6.23-rc4-mm1).

Signed-off-by : Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Signed-off-by : Dhaval Giani <dhaval@linux.vnet.ibm.com>

---
 include/linux/container_subsys.h |    5 
 init/Kconfig                     |    9 +
 kernel/sched.c                   |  311 +++++++++++++++++++++++++++++++++++++--
 kernel/sched_fair.c              |    3 
 4 files changed, 313 insertions(+), 15 deletions(-)

Index: current/include/linux/container_subsys.h
===================================================================
--- current.orig/include/linux/container_subsys.h
+++ current/include/linux/container_subsys.h
@@ -36,3 +36,8 @@ SUBSYS(mem_container)
 #endif
 
 /* */
+#ifdef CONFIG_FAIR_GROUP_SCHED
+SUBSYS(cpu_controller)
+#endif
+
+/* */
Index: current/init/Kconfig
===================================================================
--- current.orig/init/Kconfig
+++ current/init/Kconfig
@@ -326,6 +326,15 @@ config RESOURCE_COUNTERS
           infrastructure that works with containers
 	depends on CONTAINERS
 
+config FAIR_GROUP_SCHED
+	bool "Fair group scheduler"
+	depends on EXPERIMENTAL && CONTAINERS
+	help
+	  This option enables you to group tasks and control CPU resource
+	  allocation to such groups.
+
+	  Say N if unsure.
+
 config SYSFS_DEPRECATED
 	bool "Create deprecated sysfs files"
 	default y
Index: current/kernel/sched.c
===================================================================
--- current.orig/kernel/sched.c
+++ current/kernel/sched.c
@@ -179,6 +179,58 @@ struct load_stat {
 	unsigned long delta_fair, delta_exec, delta_stat;
 };
 
+#ifdef CONFIG_FAIR_GROUP_SCHED
+
+#include <linux/container.h>
+
+struct cfs_rq;
+
+/* task group related information */
+struct task_grp {
+	struct container_subsys_state css;
+	/* schedulable entities of this group on each cpu */
+	struct sched_entity **se;
+	/* runqueue "owned" by this group on each cpu */
+	struct cfs_rq **cfs_rq;
+	unsigned long shares;
+};
+
+/* Default task group's sched entity on each cpu */
+static DEFINE_PER_CPU(struct sched_entity, init_sched_entity);
+/* Default task group's cfs_rq on each cpu */
+static DEFINE_PER_CPU(struct cfs_rq, init_cfs_rq) ____cacheline_aligned_in_smp;
+
+static struct sched_entity *init_sched_entity_p[CONFIG_NR_CPUS];
+static struct cfs_rq *init_cfs_rq_p[CONFIG_NR_CPUS];
+
+/* Default task group.
+ * 	Every task in system belong to this group at bootup.
+ */
+static struct task_grp init_task_grp =  {
+					.se     = init_sched_entity_p,
+					.cfs_rq = init_cfs_rq_p,
+					};
+
+/* return group to which a task belongs */
+static inline struct task_grp *task_grp(struct task_struct *p)
+{
+	return container_of(task_subsys_state(p, cpu_controller_subsys_id),
+				struct task_grp, css);
+}
+
+/* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
+static inline void set_task_cfs_rq(struct task_struct *p)
+{
+	p->se.cfs_rq = task_grp(p)->cfs_rq[task_cpu(p)];
+	p->se.parent = task_grp(p)->se[task_cpu(p)];
+}
+
+#else
+
+static inline void set_task_cfs_rq(struct task_struct *p) { }
+
+#endif	/* CONFIG_FAIR_GROUP_SCHED */
+
 /* CFS-related fields in a runqueue */
 struct cfs_rq {
 	struct load_weight load;
@@ -208,6 +260,7 @@ struct cfs_rq {
 	 * list is used during load balance.
 	 */
 	struct list_head leaf_cfs_rq_list; /* Better name : task_cfs_rq_list? */
+	struct task_grp *tg;    /* group that "owns" this runqueue */
 #endif
 };
 
@@ -405,18 +458,6 @@ unsigned long long cpu_clock(int cpu)
 
 EXPORT_SYMBOL_GPL(cpu_clock);
 
-#ifdef CONFIG_FAIR_GROUP_SCHED
-/* Change a task's ->cfs_rq if it moves across CPUs */
-static inline void set_task_cfs_rq(struct task_struct *p)
-{
-	p->se.cfs_rq = &task_rq(p)->cfs;
-}
-#else
-static inline void set_task_cfs_rq(struct task_struct *p)
-{
-}
-#endif
-
 #ifndef prepare_arch_switch
 # define prepare_arch_switch(next)	do { } while (0)
 #endif
@@ -6567,7 +6608,25 @@ void __init sched_init(void)
 		init_cfs_rq(&rq->cfs, rq);
 #ifdef CONFIG_FAIR_GROUP_SCHED
 		INIT_LIST_HEAD(&rq->leaf_cfs_rq_list);
-		list_add(&rq->cfs.leaf_cfs_rq_list, &rq->leaf_cfs_rq_list);
+	 	{
+ 			struct cfs_rq *cfs_rq = &per_cpu(init_cfs_rq, i);
+ 			struct sched_entity *se =
+ 					 &per_cpu(init_sched_entity, i);
+
+ 			init_cfs_rq_p[i] = cfs_rq;
+ 			init_cfs_rq(cfs_rq, rq);
+ 			cfs_rq->tg = &init_task_grp;
+ 			list_add(&cfs_rq->leaf_cfs_rq_list,
+							 &rq->leaf_cfs_rq_list);
+
+ 			init_sched_entity_p[i] = se;
+ 			se->cfs_rq = &rq->cfs;
+ 			se->my_q = cfs_rq;
+ 			se->load.weight = NICE_0_LOAD;
+			se->load.inv_weight = div64_64(1ULL<<32, NICE_0_LOAD);
+ 			se->parent = NULL;
+ 		}
+		init_task_grp.shares = NICE_0_LOAD;
 #endif
 		rq->ls.load_update_last = now;
 		rq->ls.load_update_start = now;
@@ -6764,3 +6823,229 @@ void set_curr_task(int cpu, struct task_
 }
 
 #endif
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+
+/* return corresponding task_grp object of a container */
+static inline struct task_grp *container_tg(struct container *cont)
+{
+	return container_of(container_subsys_state(cont,
+			 cpu_controller_subsys_id), struct task_grp, css);
+}
+
+/* allocate runqueue etc for a new task group */
+static struct container_subsys_state *
+sched_create_group(struct container_subsys *ss, struct container *cont)
+{
+	struct task_grp *tg;
+	struct cfs_rq *cfs_rq;
+	struct sched_entity *se;
+	int i;
+
+	if (!cont->parent) {
+		/* This is early initialization for the top container */
+		init_task_grp.css.container = cont;
+		return &init_task_grp.css;
+	}
+
+	/* we support only 1-level deep hierarchical scheduler atm */
+	if (cont->parent->parent)
+		return ERR_PTR(-EINVAL);
+
+	tg = kzalloc(sizeof(*tg), GFP_KERNEL);
+	if (!tg)
+		return ERR_PTR(-ENOMEM);
+
+	tg->cfs_rq = kzalloc(sizeof(cfs_rq) * num_possible_cpus(), GFP_KERNEL);
+	if (!tg->cfs_rq)
+		goto err;
+	tg->se = kzalloc(sizeof(se) * num_possible_cpus(), GFP_KERNEL);
+	if (!tg->se)
+		goto err;
+
+	for_each_possible_cpu(i) {
+		struct rq *rq = cpu_rq(i);
+
+		cfs_rq = kmalloc_node(sizeof(struct cfs_rq), GFP_KERNEL,
+							 cpu_to_node(i));
+		if (!cfs_rq)
+			goto err;
+
+		se = kmalloc_node(sizeof(struct sched_entity), GFP_KERNEL,
+							cpu_to_node(i));
+		if (!se)
+			goto err;
+
+		memset(cfs_rq, 0, sizeof(struct cfs_rq));
+		memset(se, 0, sizeof(struct sched_entity));
+
+		tg->cfs_rq[i] = cfs_rq;
+		init_cfs_rq(cfs_rq, rq);
+		cfs_rq->tg = tg;
+		list_add_rcu(&cfs_rq->leaf_cfs_rq_list, &rq->leaf_cfs_rq_list);
+
+		tg->se[i] = se;
+		se->cfs_rq = &rq->cfs;
+		se->my_q = cfs_rq;
+		se->load.weight = NICE_0_LOAD;
+		se->load.inv_weight = div64_64(1ULL<<32, NICE_0_LOAD);
+		se->parent = NULL;
+	}
+
+	tg->shares = NICE_0_LOAD;
+
+	/* Bind the container to task_grp object we just created */
+	tg->css.container = cont;
+
+	return &tg->css;
+
+err:
+	for_each_possible_cpu(i) {
+		if (tg->cfs_rq && tg->cfs_rq[i])
+			kfree(tg->cfs_rq[i]);
+		if (tg->se && tg->se[i])
+			kfree(tg->se[i]);
+	}
+	if (tg->cfs_rq)
+		kfree(tg->cfs_rq);
+	if (tg->se)
+		kfree(tg->se);
+	if (tg)
+		kfree(tg);
+
+	return ERR_PTR(-ENOMEM);
+}
+
+
+/* destroy runqueue etc associated with a task group */
+static void sched_destroy_group(struct container_subsys *ss,
+					struct container *cont)
+{
+	struct task_grp *tg = container_tg(cont);
+	struct cfs_rq *cfs_rq;
+	struct sched_entity *se;
+	int i;
+
+	for_each_possible_cpu(i) {
+		cfs_rq = tg->cfs_rq[i];
+		list_del_rcu(&cfs_rq->leaf_cfs_rq_list);
+	}
+
+	/* wait for possible concurrent references to cfs_rqs complete */
+	synchronize_sched();
+
+	/* now it should be safe to free those cfs_rqs */
+	for_each_possible_cpu(i) {
+		cfs_rq = tg->cfs_rq[i];
+		kfree(cfs_rq);
+
+		se = tg->se[i];
+		kfree(se);
+	}
+
+	kfree(tg);
+}
+
+/* change task's runqueue when it moves between groups */
+static void sched_move_task(struct container_subsys *ss, struct container *cont,
+			struct container *old_cont, struct task_struct *tsk)
+{
+	int on_rq;
+	unsigned long flags;
+	struct rq *rq;
+
+	rq = task_rq_lock(tsk, &flags);
+
+	on_rq = tsk->se.on_rq;
+	if (on_rq)
+		deactivate_task(rq, tsk, 0);
+
+	if (unlikely(rq->curr == tsk) && tsk->sched_class == &fair_sched_class)
+		tsk->sched_class->put_prev_task(rq, tsk);
+
+	set_task_cfs_rq(tsk);
+
+	if (on_rq)
+		 activate_task(rq, tsk, 0);
+
+	if (unlikely(rq->curr == tsk) && tsk->sched_class == &fair_sched_class)
+		tsk->sched_class->set_curr_task(rq);
+
+	task_rq_unlock(rq, &flags);
+}
+
+static void set_se_shares(struct sched_entity *se, unsigned long shares)
+{
+	struct cfs_rq *cfs_rq = se->cfs_rq;
+	struct rq *rq = cfs_rq->rq;
+	int on_rq;
+
+	spin_lock_irq(&rq->lock);
+
+	on_rq = se->on_rq;
+	if (on_rq)
+		__dequeue_entity(cfs_rq, se);
+
+	se->load.weight = shares;
+	se->load.inv_weight = div64_64((1ULL<<32), shares);
+
+	if (on_rq)
+		__enqueue_entity(cfs_rq, se);
+
+	spin_unlock_irq(&rq->lock);
+}
+
+static ssize_t cpu_shares_write(struct container *cont, struct cftype *cftype,
+				struct file *file, const char __user *userbuf,
+				size_t nbytes, loff_t *ppos)
+{
+	int i;
+	unsigned long shareval;
+	struct task_grp *tg = container_tg(cont);
+	char buffer[2*sizeof(unsigned long)];
+
+	if (nbytes > 2*sizeof(unsigned long))	/* safety check */
+		return -E2BIG;
+
+	if (copy_from_user(buffer, userbuf, nbytes))
+		return -EFAULT;
+
+	buffer[nbytes] = 0;	/* nul-terminate */
+
...

Re: [PATCH] Hookup group-scheduler with task container infrastructure [message #20032 is a reply to message #20031] Mon, 10 September 2007 22:28 Go to previous messageGo to next message
Dmitry Adamushko is currently offline  Dmitry Adamushko
Messages: 20
Registered: June 2007
Junior Member
On 10/09/2007, Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> wrote:
> On Mon, Sep 10, 2007 at 10:22:59AM -0700, Andrew Morton wrote:
> > objection ;)  "cpuctlr" isn't memorable.  Kernel code is write-rarely,
> > read-often.  "cpu_controller", please.  The extra typing is worth it ;)
>
> Ok! Here's the modified patch (against 2.6.23-rc4-mm1).
>
> [ ... ]
>
> +/* change task's runqueue when it moves between groups */
> +static void sched_move_task(struct container_subsys *ss, struct container *cont,
> +                       struct container *old_cont, struct task_struct *tsk)
> +{
> +       int on_rq;
> +       unsigned long flags;
> +       struct rq *rq;
> +
> +       rq = task_rq_lock(tsk, &flags);
> +

I guess, update_rq_clock(rq) should be placed here.

humm... do you really need deactivate/activate_task() here? 'rq' and
p->se.load.weight stay unchanged so enqueue/dequeue_task() would do a
job, no?
Although, I might be missing (definitely, as this part is not
completely clear to me yet) something important at this late hour :)


> +       on_rq = tsk->se.on_rq;
> +       if (on_rq)
> +               deactivate_task(rq, tsk, 0);
> +
> +       if (unlikely(rq->curr == tsk) && tsk->sched_class == &fair_sched_class)
> +               tsk->sched_class->put_prev_task(rq, tsk);
> +
> +       set_task_cfs_rq(tsk);
> +
> +       if (on_rq)
> +                activate_task(rq, tsk, 0);
> +
> +       if (unlikely(rq->curr == tsk) && tsk->sched_class == &fair_sched_class)
> +               tsk->sched_class->set_curr_task(rq);
> +
> +       task_rq_unlock(rq, &flags);
> +}
> +


-- 
Best regards,
Dmitry Adamushko
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Re: [PATCH] Hookup group-scheduler with task container infrastructure [message #20033 is a reply to message #20031] Mon, 10 September 2007 22:37 Go to previous messageGo to next message
Dmitry Adamushko is currently offline  Dmitry Adamushko
Messages: 20
Registered: June 2007
Junior Member
On 10/09/2007, Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> wrote:
> On Mon, Sep 10, 2007 at 10:22:59AM -0700, Andrew Morton wrote:
> > objection ;)  "cpuctlr" isn't memorable.  Kernel code is write-rarely,
> > read-often.  "cpu_controller", please.  The extra typing is worth it ;)
>
> Ok! Here's the modified patch (against 2.6.23-rc4-mm1).

as everyone seems to be in a quest for a better name... I think, the
obvious one would be just 'group_sched'.


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Re: [PATCH] Hookup group-scheduler with task container infrastructure [message #20037 is a reply to message #20032] Tue, 11 September 2007 04:41 Go to previous messageGo to next message
Srivatsa Vaddagiri is currently offline  Srivatsa Vaddagiri
Messages: 241
Registered: August 2006
Senior Member
On Tue, Sep 11, 2007 at 12:28:51AM +0200, Dmitry Adamushko wrote:
> > +       rq = task_rq_lock(tsk, &flags);
> > +
> 
> I guess, update_rq_clock(rq) should be placed here.
> 
> humm... do you really need deactivate/activate_task() here? 'rq' and
> p->se.load.weight stay unchanged so enqueue/dequeue_task() would do a
> job, no?

Good catch. Here's the updated patch.


Signed-off-by : Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Signed-off-by : Dhaval Giani <dhaval@linux.vnet.ibm.com>


---
 include/linux/container_subsys.h |    6 
 init/Kconfig                     |    9 +
 kernel/sched.c                   |  312 +++++++++++++++++++++++++++++++++++++--
 kernel/sched_fair.c              |    3 
 4 files changed, 315 insertions(+), 15 deletions(-)

Index: current/include/linux/container_subsys.h
===================================================================
--- current.orig/include/linux/container_subsys.h
+++ current/include/linux/container_subsys.h
@@ -36,3 +36,9 @@ SUBSYS(mem_container)
 #endif
 
 /* */
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+SUBSYS(cpu)
+#endif
+
+/* */
Index: current/init/Kconfig
===================================================================
--- current.orig/init/Kconfig
+++ current/init/Kconfig
@@ -326,6 +326,15 @@ config RESOURCE_COUNTERS
           infrastructure that works with containers
 	depends on CONTAINERS
 
+config FAIR_GROUP_SCHED
+	bool "Fair group scheduler"
+	depends on EXPERIMENTAL && CONTAINERS
+	help
+	  This option enables you to group tasks and control CPU resource
+	  allocation to such groups.
+
+	  Say N if unsure.
+
 config SYSFS_DEPRECATED
 	bool "Create deprecated sysfs files"
 	default y
Index: current/kernel/sched.c
===================================================================
--- current.orig/kernel/sched.c
+++ current/kernel/sched.c
@@ -179,6 +179,58 @@ struct load_stat {
 	unsigned long delta_fair, delta_exec, delta_stat;
 };
 
+#ifdef CONFIG_FAIR_GROUP_SCHED
+
+#include <linux/container.h>
+
+struct cfs_rq;
+
+/* task group related information */
+struct task_grp {
+	struct container_subsys_state css;
+	/* schedulable entities of this group on each cpu */
+	struct sched_entity **se;
+	/* runqueue "owned" by this group on each cpu */
+	struct cfs_rq **cfs_rq;
+	unsigned long shares;
+};
+
+/* Default task group's sched entity on each cpu */
+static DEFINE_PER_CPU(struct sched_entity, init_sched_entity);
+/* Default task group's cfs_rq on each cpu */
+static DEFINE_PER_CPU(struct cfs_rq, init_cfs_rq) ____cacheline_aligned_in_smp;
+
+static struct sched_entity *init_sched_entity_p[CONFIG_NR_CPUS];
+static struct cfs_rq *init_cfs_rq_p[CONFIG_NR_CPUS];
+
+/* Default task group.
+ * 	Every task in system belong to this group at bootup.
+ */
+static struct task_grp init_task_grp =  {
+					.se     = init_sched_entity_p,
+					.cfs_rq = init_cfs_rq_p,
+					};
+
+/* return group to which a task belongs */
+static inline struct task_grp *task_grp(struct task_struct *p)
+{
+	return container_of(task_subsys_state(p, cpu_subsys_id),
+				struct task_grp, css);
+}
+
+/* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
+static inline void set_task_cfs_rq(struct task_struct *p)
+{
+	p->se.cfs_rq = task_grp(p)->cfs_rq[task_cpu(p)];
+	p->se.parent = task_grp(p)->se[task_cpu(p)];
+}
+
+#else
+
+static inline void set_task_cfs_rq(struct task_struct *p) { }
+
+#endif	/* CONFIG_FAIR_GROUP_SCHED */
+
 /* CFS-related fields in a runqueue */
 struct cfs_rq {
 	struct load_weight load;
@@ -208,6 +260,7 @@ struct cfs_rq {
 	 * list is used during load balance.
 	 */
 	struct list_head leaf_cfs_rq_list; /* Better name : task_cfs_rq_list? */
+	struct task_grp *tg;    /* group that "owns" this runqueue */
 #endif
 };
 
@@ -405,18 +458,6 @@ unsigned long long cpu_clock(int cpu)
 
 EXPORT_SYMBOL_GPL(cpu_clock);
 
-#ifdef CONFIG_FAIR_GROUP_SCHED
-/* Change a task's ->cfs_rq if it moves across CPUs */
-static inline void set_task_cfs_rq(struct task_struct *p)
-{
-	p->se.cfs_rq = &task_rq(p)->cfs;
-}
-#else
-static inline void set_task_cfs_rq(struct task_struct *p)
-{
-}
-#endif
-
 #ifndef prepare_arch_switch
 # define prepare_arch_switch(next)	do { } while (0)
 #endif
@@ -6567,7 +6608,25 @@ void __init sched_init(void)
 		init_cfs_rq(&rq->cfs, rq);
 #ifdef CONFIG_FAIR_GROUP_SCHED
 		INIT_LIST_HEAD(&rq->leaf_cfs_rq_list);
-		list_add(&rq->cfs.leaf_cfs_rq_list, &rq->leaf_cfs_rq_list);
+	 	{
+ 			struct cfs_rq *cfs_rq = &per_cpu(init_cfs_rq, i);
+ 			struct sched_entity *se =
+ 					 &per_cpu(init_sched_entity, i);
+
+ 			init_cfs_rq_p[i] = cfs_rq;
+ 			init_cfs_rq(cfs_rq, rq);
+ 			cfs_rq->tg = &init_task_grp;
+ 			list_add(&cfs_rq->leaf_cfs_rq_list,
+							 &rq->leaf_cfs_rq_list);
+
+ 			init_sched_entity_p[i] = se;
+ 			se->cfs_rq = &rq->cfs;
+ 			se->my_q = cfs_rq;
+ 			se->load.weight = NICE_0_LOAD;
+			se->load.inv_weight = div64_64(1ULL<<32, NICE_0_LOAD);
+ 			se->parent = NULL;
+ 		}
+		init_task_grp.shares = NICE_0_LOAD;
 #endif
 		rq->ls.load_update_last = now;
 		rq->ls.load_update_start = now;
@@ -6764,3 +6823,230 @@ void set_curr_task(int cpu, struct task_
 }
 
 #endif
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+
+/* return corresponding task_grp object of a container */
+static inline struct task_grp *container_tg(struct container *cont)
+{
+	return container_of(container_subsys_state(cont, cpu_subsys_id),
+					 struct task_grp, css);
+}
+
+/* allocate runqueue etc for a new task group */
+static struct container_subsys_state *
+sched_create_group(struct container_subsys *ss, struct container *cont)
+{
+	struct task_grp *tg;
+	struct cfs_rq *cfs_rq;
+	struct sched_entity *se;
+	int i;
+
+	if (!cont->parent) {
+		/* This is early initialization for the top container */
+		init_task_grp.css.container = cont;
+		return &init_task_grp.css;
+	}
+
+	/* we support only 1-level deep hierarchical scheduler atm */
+	if (cont->parent->parent)
+		return ERR_PTR(-EINVAL);
+
+	tg = kzalloc(sizeof(*tg), GFP_KERNEL);
+	if (!tg)
+		return ERR_PTR(-ENOMEM);
+
+	tg->cfs_rq = kzalloc(sizeof(cfs_rq) * num_possible_cpus(), GFP_KERNEL);
+	if (!tg->cfs_rq)
+		goto err;
+	tg->se = kzalloc(sizeof(se) * num_possible_cpus(), GFP_KERNEL);
+	if (!tg->se)
+		goto err;
+
+	for_each_possible_cpu(i) {
+		struct rq *rq = cpu_rq(i);
+
+		cfs_rq = kmalloc_node(sizeof(struct cfs_rq), GFP_KERNEL,
+							 cpu_to_node(i));
+		if (!cfs_rq)
+			goto err;
+
+		se = kmalloc_node(sizeof(struct sched_entity), GFP_KERNEL,
+							cpu_to_node(i));
+		if (!se)
+			goto err;
+
+		memset(cfs_rq, 0, sizeof(struct cfs_rq));
+		memset(se, 0, sizeof(struct sched_entity));
+
+		tg->cfs_rq[i] = cfs_rq;
+		init_cfs_rq(cfs_rq, rq);
+		cfs_rq->tg = tg;
+		list_add_rcu(&cfs_rq->leaf_cfs_rq_list, &rq->leaf_cfs_rq_list);
+
+		tg->se[i] = se;
+		se->cfs_rq = &rq->cfs;
+		se->my_q = cfs_rq;
+		se->load.weight = NICE_0_LOAD;
+		se->load.inv_weight = div64_64(1ULL<<32, NICE_0_LOAD);
+		se->parent = NULL;
+	}
+
+	tg->shares = NICE_0_LOAD;
+
+	/* Bind the container to task_grp object we just created */
+	tg->css.container = cont;
+
+	return &tg->css;
+
+err:
+	for_each_possible_cpu(i) {
+		if (tg->cfs_rq && tg->cfs_rq[i])
+			kfree(tg->cfs_rq[i]);
+		if (tg->se && tg->se[i])
+			kfree(tg->se[i]);
+	}
+	if (tg->cfs_rq)
+		kfree(tg->cfs_rq);
+	if (tg->se)
+		kfree(tg->se);
+	if (tg)
+		kfree(tg);
+
+	return ERR_PTR(-ENOMEM);
+}
+
+
+/* destroy runqueue etc associated with a task group */
+static void sched_destroy_group(struct container_subsys *ss,
+					struct container *cont)
+{
+	struct task_grp *tg = container_tg(cont);
+	struct cfs_rq *cfs_rq;
+	struct sched_entity *se;
+	int i;
+
+	for_each_possible_cpu(i) {
+		cfs_rq = tg->cfs_rq[i];
+		list_del_rcu(&cfs_rq->leaf_cfs_rq_list);
+	}
+
+	/* wait for possible concurrent references to cfs_rqs complete */
+	synchronize_sched();
+
+	/* now it should be safe to free those cfs_rqs */
+	for_each_possible_cpu(i) {
+		cfs_rq = tg->cfs_rq[i];
+		kfree(cfs_rq);
+
+		se = tg->se[i];
+		kfree(se);
+	}
+
+	kfree(tg);
+}
+
+/* change task's runqueue when it moves between groups */
+static void sched_move_task(struct container_subsys *ss, struct container *cont,
+			struct container *old_cont, struct task_struct *tsk)
+{
+	int on_rq;
+	unsigned long flags;
+	struct rq *rq;
+
+	rq = task_rq_lock(tsk, &flags);
+	update_rq_clock(rq);
+
+	on_rq = tsk->se.on_rq;
+	if (on_rq)
+		dequeue_task(rq, tsk, 0);
+
+	if (unlikely(rq->curr == tsk) && tsk->sched_class == &fair_sched_class)
+		tsk->sched_class->put_prev_task(rq, tsk);
+
+	set_task_cfs_rq(tsk);
+
+	if (on_rq)
+		 enqueue_task(rq, tsk, 0);
+
+	if (unlikely(rq->curr == tsk) && tsk->sched_class == &fair_sched_class)
+		tsk->sched_class->set_curr_task(rq);
+
+	task_rq_unlock(rq, &flags);
+}
+
+static void set_se_shares(struct sched_entity *se, unsigned long shares)
+{
+	struct cfs_rq *cfs_rq = se->cfs_rq;
+	struct rq *rq = cfs_rq->rq;
+	int on_rq;
+
+	spin_lock_irq(&rq->lock);
+
+	on_rq = se->on_rq;
+	if (on_rq)
+		__dequeue_entity(cfs_rq, se);
+
+	se->load.weight = shares;
+	se->load.inv_weight = div64_64((1ULL<<32), shares);
+
+	if (on_rq)
+		__enqueue_entity(cfs_rq, se);
+
+	spin_unlock_irq(&rq->lock);
+}
+
+static ssize_t cpu_shares_write(struct container *cont, struct cftype *cftype,
+				struct file *file, const char __user *userbuf,
+				size_t nbytes, loff_t *ppos)
+{
+	int i;
+	unsigned long shareval;
+	struct task_grp *tg = container_tg(cont);
+	char buffer[2*sizeof(unsigned long) + 1];
+
+	if (nbytes > 2*sizeof(unsigned long))	/* safety check */
+		return -E2BIG;
+
+	
...

Re: Re: [PATCH] Hookup group-scheduler with task container infrastructure [message #20038 is a reply to message #20004] Tue, 11 September 2007 04:44 Go to previous messageGo to next message
Srivatsa Vaddagiri is currently offline  Srivatsa Vaddagiri
Messages: 241
Registered: August 2006
Senior Member
On Mon, Sep 10, 2007 at 11:38:10AM -0700, Paul Menage wrote:
> By definition any container (about to be renamed control group)
> subsystem is some kind of "controller" so that bit seems a bit
> redundant.
> 
> Any reason not to just call it "cpu" or "cpu_sched"

Done (in the latest patch I sent a while back)!

-- 
Regards,
vatsa
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Containers mailing list
Containers@lists.linux-foundation.org
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Re: [PATCH] Hookup group-scheduler with task container infrastructure [message #20040 is a reply to message #20037] Tue, 11 September 2007 09:53 Go to previous messageGo to next message
Dmitry Adamushko is currently offline  Dmitry Adamushko
Messages: 20
Registered: June 2007
Junior Member
On 11/09/2007, Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> wrote:
>
> [ ... ]

I guess, 'rq->curr == tsk' implies a task was on the 'rq' (before
dequeueing) in this particular case. What's about a minor optimization
like below (plus, let's make use of task_running()):

[ btw., real-time task can be also added to a container, right? I
guess, it can be used at least for group-aware load-balancing of
rt_tasks... otherwise, I guess, cpu-resource controlling is not that
applicable to, say, SCHED_FIFO :-)
Anyway, to this goal rt_task should become aware of group-related bits
of the 'struct sched_entity'... and at the moment, the code below is
effectively just a 'nop' for them.. right? ]

/* change task's runqueue when it moves between groups */
static void sched_move_task(struct container_subsys *ss, struct container *cont,
                      struct container *old_cont, struct task_struct *tsk)
{
       int on_rq, running;
       unsigned long flags;
       struct rq *rq;

       rq = task_rq_lock(tsk, &flags);
       update_rq_clock(rq);

       running = task_running(rq, tsk);
       on_rq = tsk->se.on_rq;
       if (on_rq) {
               dequeue_task(rq, tsk, 0);

               if (unlikely(running) && tsk->sched_class == &fair_sched_class)
                      tsk->sched_class->put_prev_task(rq, tsk);
       }

       set_task_cfs_rq(tsk);

       if (on_rq) {
                enqueue_task(rq, tsk, 0);

                if (unlikely(running) && tsk->sched_class == &fair_sched_class)
                       tsk->sched_class->set_curr_task(rq);
       }

       task_rq_unlock(rq, &flags);
}


> --
> Regards,
> vatsa
>

-- 
Best regards,
Dmitry Adamushko
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Re: [PATCH] Hookup group-scheduler with task container infrastructure [message #20121 is a reply to message #20040] Wed, 12 September 2007 11:33 Go to previous messageGo to next message
Srivatsa Vaddagiri is currently offline  Srivatsa Vaddagiri
Messages: 241
Registered: August 2006
Senior Member
On Tue, Sep 11, 2007 at 11:53:51AM +0200, Dmitry Adamushko wrote:
> I guess, 'rq->curr == tsk' implies a task was on the 'rq' (before
> dequeueing) in this particular case. What's about a minor optimization
> like below (plus, let's make use of task_running()):

Hi Dmitry,
	The modified code looks very good to me (and neater too!). Updated 
patch below.

> [ btw., real-time task can be also added to a container, right?

I am not sure whether we want to allow that. I have been assuming that
only SCHED_NORMAL tasks will be in containers.

Imagine two SCHED_FIFO tasks being put in two different containers -and- 
controlling cpu cycle allocation to both containers. Do we actually timeslice 
the two SCHED_FIFO tasks now that are across containers? Also we need a
mechanism to choose a container first to schedule and then the real-time
task in it (similar to how its being done in SCHED_NORMAL case). Which
means we need one rt_rq per container per cpu.

Kirill, do you require real-time tasks to be present in containers?

> I guess, it can be used at least for group-aware load-balancing of
> rt_tasks... otherwise, I guess, cpu-resource controlling is not that
> applicable to, say, SCHED_FIFO :-)

Yes, if we were to allow SCHED_FIFO/RR tasks in containers, then the
load balancer would need to spread rt-tasks of a container across CPUs
to ensure low scheduling latencies for them.

> Anyway, to this goal rt_task should become aware of group-related bits
> of the 'struct sched_entity'... and at the moment, the code below is
> effectively just a 'nop' for them.. right? ]

Yes. To emphasise this code doesn't support real-time tasks in a container, I 
am returning -ENOTSUP when trying to move a rt-task into a container.

Thanks for all your review!




Add interface to control cpu bandwidth allocation to task-groups.

Signed-off-by : Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Signed-off-by : Dhaval Giani <dhaval@linux.vnet.ibm.com>


---
 include/linux/container_subsys.h |    6 
 init/Kconfig                     |    9 +
 kernel/sched.c                   |  330 +++++++++++++++++++++++++++++++++++++--
 kernel/sched_fair.c              |    3 
 4 files changed, 333 insertions(+), 15 deletions(-)

Index: current/include/linux/container_subsys.h
===================================================================
--- current.orig/include/linux/container_subsys.h
+++ current/include/linux/container_subsys.h
@@ -36,3 +36,9 @@ SUBSYS(mem_container)
 #endif
 
 /* */
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+SUBSYS(cpu)
+#endif
+
+/* */
Index: current/init/Kconfig
===================================================================
--- current.orig/init/Kconfig
+++ current/init/Kconfig
@@ -326,6 +326,15 @@ config RESOURCE_COUNTERS
           infrastructure that works with containers
 	depends on CONTAINERS
 
+config FAIR_GROUP_SCHED
+	bool "Fair group scheduler"
+	depends on EXPERIMENTAL && CONTAINERS
+	help
+	  This option enables you to group tasks and control CPU resource
+	  allocation to such groups.
+
+	  Say N if unsure.
+
 config SYSFS_DEPRECATED
 	bool "Create deprecated sysfs files"
 	default y
Index: current/kernel/sched.c
===================================================================
--- current.orig/kernel/sched.c
+++ current/kernel/sched.c
@@ -179,6 +179,58 @@ struct load_stat {
 	unsigned long delta_fair, delta_exec, delta_stat;
 };
 
+#ifdef CONFIG_FAIR_GROUP_SCHED
+
+#include <linux/container.h>
+
+struct cfs_rq;
+
+/* task group related information */
+struct task_grp {
+	struct container_subsys_state css;
+	/* schedulable entities of this group on each cpu */
+	struct sched_entity **se;
+	/* runqueue "owned" by this group on each cpu */
+	struct cfs_rq **cfs_rq;
+	unsigned long shares;
+};
+
+/* Default task group's sched entity on each cpu */
+static DEFINE_PER_CPU(struct sched_entity, init_sched_entity);
+/* Default task group's cfs_rq on each cpu */
+static DEFINE_PER_CPU(struct cfs_rq, init_cfs_rq) ____cacheline_aligned_in_smp;
+
+static struct sched_entity *init_sched_entity_p[CONFIG_NR_CPUS];
+static struct cfs_rq *init_cfs_rq_p[CONFIG_NR_CPUS];
+
+/* Default task group.
+ * 	Every task in system belong to this group at bootup.
+ */
+static struct task_grp init_task_grp =  {
+					.se     = init_sched_entity_p,
+					.cfs_rq = init_cfs_rq_p,
+					};
+
+/* return group to which a task belongs */
+static inline struct task_grp *task_grp(struct task_struct *p)
+{
+	return container_of(task_subsys_state(p, cpu_subsys_id),
+				struct task_grp, css);
+}
+
+/* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
+static inline void set_task_cfs_rq(struct task_struct *p)
+{
+	p->se.cfs_rq = task_grp(p)->cfs_rq[task_cpu(p)];
+	p->se.parent = task_grp(p)->se[task_cpu(p)];
+}
+
+#else
+
+static inline void set_task_cfs_rq(struct task_struct *p) { }
+
+#endif	/* CONFIG_FAIR_GROUP_SCHED */
+
 /* CFS-related fields in a runqueue */
 struct cfs_rq {
 	struct load_weight load;
@@ -208,6 +260,7 @@ struct cfs_rq {
 	 * list is used during load balance.
 	 */
 	struct list_head leaf_cfs_rq_list; /* Better name : task_cfs_rq_list? */
+	struct task_grp *tg;    /* group that "owns" this runqueue */
 #endif
 };
 
@@ -405,18 +458,6 @@ unsigned long long cpu_clock(int cpu)
 
 EXPORT_SYMBOL_GPL(cpu_clock);
 
-#ifdef CONFIG_FAIR_GROUP_SCHED
-/* Change a task's ->cfs_rq if it moves across CPUs */
-static inline void set_task_cfs_rq(struct task_struct *p)
-{
-	p->se.cfs_rq = &task_rq(p)->cfs;
-}
-#else
-static inline void set_task_cfs_rq(struct task_struct *p)
-{
-}
-#endif
-
 #ifndef prepare_arch_switch
 # define prepare_arch_switch(next)	do { } while (0)
 #endif
@@ -6567,7 +6608,25 @@ void __init sched_init(void)
 		init_cfs_rq(&rq->cfs, rq);
 #ifdef CONFIG_FAIR_GROUP_SCHED
 		INIT_LIST_HEAD(&rq->leaf_cfs_rq_list);
-		list_add(&rq->cfs.leaf_cfs_rq_list, &rq->leaf_cfs_rq_list);
+	 	{
+ 			struct cfs_rq *cfs_rq = &per_cpu(init_cfs_rq, i);
+ 			struct sched_entity *se =
+ 					 &per_cpu(init_sched_entity, i);
+
+ 			init_cfs_rq_p[i] = cfs_rq;
+ 			init_cfs_rq(cfs_rq, rq);
+ 			cfs_rq->tg = &init_task_grp;
+ 			list_add(&cfs_rq->leaf_cfs_rq_list,
+							 &rq->leaf_cfs_rq_list);
+
+ 			init_sched_entity_p[i] = se;
+ 			se->cfs_rq = &rq->cfs;
+ 			se->my_q = cfs_rq;
+ 			se->load.weight = NICE_0_LOAD;
+			se->load.inv_weight = div64_64(1ULL<<32, NICE_0_LOAD);
+ 			se->parent = NULL;
+ 		}
+		init_task_grp.shares = NICE_0_LOAD;
 #endif
 		rq->ls.load_update_last = now;
 		rq->ls.load_update_start = now;
@@ -6764,3 +6823,248 @@ void set_curr_task(int cpu, struct task_
 }
 
 #endif
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+
+/* return corresponding task_grp object of a container */
+static inline struct task_grp *container_tg(struct container *cont)
+{
+	return container_of(container_subsys_state(cont, cpu_subsys_id),
+					 struct task_grp, css);
+}
+
+/* allocate runqueue etc for a new task group */
+static struct container_subsys_state *
+sched_create_group(struct container_subsys *ss, struct container *cont)
+{
+	struct task_grp *tg;
+	struct cfs_rq *cfs_rq;
+	struct sched_entity *se;
+	int i;
+
+	if (!cont->parent) {
+		/* This is early initialization for the top container */
+		init_task_grp.css.container = cont;
+		return &init_task_grp.css;
+	}
+
+	/* we support only 1-level deep hierarchical scheduler atm */
+	if (cont->parent->parent)
+		return ERR_PTR(-EINVAL);
+
+	tg = kzalloc(sizeof(*tg), GFP_KERNEL);
+	if (!tg)
+		return ERR_PTR(-ENOMEM);
+
+	tg->cfs_rq = kzalloc(sizeof(cfs_rq) * num_possible_cpus(), GFP_KERNEL);
+	if (!tg->cfs_rq)
+		goto err;
+	tg->se = kzalloc(sizeof(se) * num_possible_cpus(), GFP_KERNEL);
+	if (!tg->se)
+		goto err;
+
+	for_each_possible_cpu(i) {
+		struct rq *rq = cpu_rq(i);
+
+		cfs_rq = kmalloc_node(sizeof(struct cfs_rq), GFP_KERNEL,
+							 cpu_to_node(i));
+		if (!cfs_rq)
+			goto err;
+
+		se = kmalloc_node(sizeof(struct sched_entity), GFP_KERNEL,
+							cpu_to_node(i));
+		if (!se)
+			goto err;
+
+		memset(cfs_rq, 0, sizeof(struct cfs_rq));
+		memset(se, 0, sizeof(struct sched_entity));
+
+		tg->cfs_rq[i] = cfs_rq;
+		init_cfs_rq(cfs_rq, rq);
+		cfs_rq->tg = tg;
+		list_add_rcu(&cfs_rq->leaf_cfs_rq_list, &rq->leaf_cfs_rq_list);
+
+		tg->se[i] = se;
+		se->cfs_rq = &rq->cfs;
+		se->my_q = cfs_rq;
+		se->load.weight = NICE_0_LOAD;
+		se->load.inv_weight = div64_64(1ULL<<32, NICE_0_LOAD);
+		se->parent = NULL;
+	}
+
+	tg->shares = NICE_0_LOAD;
+
+	/* Bind the container to task_grp object we just created */
+	tg->css.container = cont;
+
+	return &tg->css;
+
+err:
+	for_each_possible_cpu(i) {
+		if (tg->cfs_rq && tg->cfs_rq[i])
+			kfree(tg->cfs_rq[i]);
+		if (tg->se && tg->se[i])
+			kfree(tg->se[i]);
+	}
+	if (tg->cfs_rq)
+		kfree(tg->cfs_rq);
+	if (tg->se)
+		kfree(tg->se);
+	if (tg)
+		kfree(tg);
+
+	return ERR_PTR(-ENOMEM);
+}
+
+
+/* destroy runqueue etc associated with a task group */
+static void sched_destroy_group(struct container_subsys *ss,
+					struct container *cont)
+{
+	struct task_grp *tg = container_tg(cont);
+	struct cfs_rq *cfs_rq;
+	struct sched_entity *se;
+	int i;
+
+	for_each_possible_cpu(i) {
+		cfs_rq = tg->cfs_rq[i];
+		list_del_rcu(&cfs_rq->leaf_cfs_rq_list);
+	}
+
+	/* wait for possible concurrent references to cfs_rqs complete */
+	synchronize_sched();
+
+	/* now it should be safe to free those cfs_rqs */
+	for_each_possible_cpu(i) {
+		cfs_rq = tg->cfs_rq[i];
+		kfree(cfs_rq);
+
+		se = tg->se[i];
+		kfree(se);
+	}
+
+	kfree(tg);
+}
+
+static int sched_can_attach(struct container_subsys *ss,
+			     struct container *cont, struct task_struct *tsk)
+{
+	/* We don't support RT-tasks being in separat
...

Re: [PATCH] Hookup group-scheduler with task container infrastructure [message #20128 is a reply to message #20121] Wed, 12 September 2007 12:05 Go to previous messageGo to next message
Srivatsa Vaddagiri is currently offline  Srivatsa Vaddagiri
Messages: 241
Registered: August 2006
Senior Member
On Wed, Sep 12, 2007 at 05:12:02PM +0530, Srivatsa Vaddagiri wrote:
> Yes. To emphasise this code doesn't support real-time tasks in a container, I 
> am returning -ENOTSUP when trying to move a rt-task into a container.

s/ENOTSUP/EINVAL

-- 
Regards,
vatsa
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Re: [PATCH] Hookup group-scheduler with task container infrastructure [message #20157 is a reply to message #20121] Wed, 12 September 2007 16:25 Go to previous messageGo to next message
Dmitry Adamushko is currently offline  Dmitry Adamushko
Messages: 20
Registered: June 2007
Junior Member
Hi Srivatsa,

please find a few more minor comments below.

> [ ... ]
> +
> +/* destroy runqueue etc associated with a task group */
> +static void sched_destroy_group(struct container_subsys *ss,
> +                                       struct container *cont)
> +{
> +       struct task_grp *tg = container_tg(cont);
> +       struct cfs_rq *cfs_rq;
> +       struct sched_entity *se;
> +       int i;
> +
> +       for_each_possible_cpu(i) {
> +               cfs_rq = tg->cfs_rq[i];
> +               list_del_rcu(&cfs_rq->leaf_cfs_rq_list);
> +       }
> +
> +       /* wait for possible concurrent references to cfs_rqs complete */
> +       synchronize_sched();
> +
> +       /* now it should be safe to free those cfs_rqs */
> +       for_each_possible_cpu(i) {
> +               cfs_rq = tg->cfs_rq[i];
> +               kfree(cfs_rq);
> +
> +               se = tg->se[i];
> +               kfree(se);
> +       }
> +
> +       kfree(tg);
> +}

kfree(tg->cfs_rq) && kfree(tg->se) ?


> +
> +/* change task's runqueue when it moves between groups */
> +static void sched_move_task(struct container_subsys *ss, struct container *cont,
> +                       struct container *old_cont, struct task_struct *tsk)
> +{
> +       int on_rq, running;
> +       unsigned long flags;
> +       struct rq *rq;
> +
> +       rq = task_rq_lock(tsk, &flags);
> +
> +       if (tsk->sched_class != &fair_sched_class)
> +               goto done;

this check should be redundant now with sched_can_attach() in place.


> +static void set_se_shares(struct sched_entity *se, unsigned long shares)
> +{
> +       struct cfs_rq *cfs_rq = se->cfs_rq;
> +       struct rq *rq = cfs_rq->rq;
> +       int on_rq;
> +
> +       spin_lock_irq(&rq->lock);
> +
> +       on_rq = se->on_rq;
> +       if (on_rq)
> +               __dequeue_entity(cfs_rq, se);
> +
> +       se->load.weight = shares;
> +       se->load.inv_weight = div64_64((1ULL<<32), shares);

A bit of nit-picking... are you sure, there is no need in non '__'
versions of dequeue/enqueu() here (at least, for the sake of
update_curr())? Although, I don't have -mm at hand at this very moment
and original -rc4 (that I have at hand) doesn't already have
'se->load' at all... so will look later.

>
> --
> Regards,
> vatsa
>


-- 
Best regards,
Dmitry Adamushko
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Re: [PATCH] Hookup group-scheduler with task container infrastructure [message #20218 is a reply to message #20157] Thu, 13 September 2007 12:27 Go to previous messageGo to next message
Srivatsa Vaddagiri is currently offline  Srivatsa Vaddagiri
Messages: 241
Registered: August 2006
Senior Member
On Wed, Sep 12, 2007 at 06:25:37PM +0200, Dmitry Adamushko wrote:
> > +       kfree(tg);
> > +}
> 
> kfree(tg->cfs_rq) && kfree(tg->se) ?

oops, yes!

> > +       if (tsk->sched_class != &fair_sched_class)
> > +               goto done;
> 
> this check should be redundant now with sched_can_attach() in place.

well, there is remote possibility that task could have changed policies
between sched_can_attach() and sched_move_task()! In the updated patch
below, I have put some hooks to deal with that scenario elsewhere also
(in rt_mutex_setprio and __setscheduler). Pls let me know if you see 
any issues with that.

> > +static void set_se_shares(struct sched_entity *se, unsigned long shares)
> > +{
> > +       struct cfs_rq *cfs_rq = se->cfs_rq;
> > +       struct rq *rq = cfs_rq->rq;
> > +       int on_rq;
> > +
> > +       spin_lock_irq(&rq->lock);
> > +
> > +       on_rq = se->on_rq;
> > +       if (on_rq)
> > +               __dequeue_entity(cfs_rq, se);
> > +
> > +       se->load.weight = shares;
> > +       se->load.inv_weight = div64_64((1ULL<<32), shares);
> 
> A bit of nit-picking... are you sure, there is no need in non '__'
> versions of dequeue/enqueu() here (at least, for the sake of

You are right, we need the dequeue/enqueue_entity here, as the sched
entity load is changing in between the two function calls.

How does the updated patch look?  (Thanks again for all your review so far!)


--


Add interface to control cpu bandwidth allocation to task-groups.

Signed-off-by : Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Signed-off-by : Dhaval Giani <dhaval@linux.vnet.ibm.com>


---
 include/linux/container_subsys.h |    6 
 init/Kconfig                     |    9 +
 kernel/sched.c                   |  344 +++++++++++++++++++++++++++++++++++++--
 kernel/sched_fair.c              |    3 
 kernel/sched_idletask.c          |    5 
 kernel/sched_rt.c                |    5 
 6 files changed, 355 insertions(+), 17 deletions(-)

Index: current/include/linux/container_subsys.h
===================================================================
--- current.orig/include/linux/container_subsys.h
+++ current/include/linux/container_subsys.h
@@ -36,3 +36,9 @@ SUBSYS(mem_container)
 #endif
 
 /* */
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+SUBSYS(cpu)
+#endif
+
+/* */
Index: current/init/Kconfig
===================================================================
--- current.orig/init/Kconfig
+++ current/init/Kconfig
@@ -326,6 +326,15 @@ config RESOURCE_COUNTERS
           infrastructure that works with containers
 	depends on CONTAINERS
 
+config FAIR_GROUP_SCHED
+	bool "Fair group scheduler"
+	depends on EXPERIMENTAL && CONTAINERS
+	help
+	  This option enables you to group tasks and control CPU resource
+	  allocation to such groups.
+
+	  Say N if unsure.
+
 config SYSFS_DEPRECATED
 	bool "Create deprecated sysfs files"
 	default y
Index: current/kernel/sched.c
===================================================================
--- current.orig/kernel/sched.c
+++ current/kernel/sched.c
@@ -179,6 +179,58 @@ struct load_stat {
 	unsigned long delta_fair, delta_exec, delta_stat;
 };
 
+#ifdef CONFIG_FAIR_GROUP_SCHED
+
+#include <linux/container.h>
+
+struct cfs_rq;
+
+/* task group related information */
+struct task_grp {
+	struct container_subsys_state css;
+	/* schedulable entities of this group on each cpu */
+	struct sched_entity **se;
+	/* runqueue "owned" by this group on each cpu */
+	struct cfs_rq **cfs_rq;
+	unsigned long shares;
+};
+
+/* Default task group's sched entity on each cpu */
+static DEFINE_PER_CPU(struct sched_entity, init_sched_entity);
+/* Default task group's cfs_rq on each cpu */
+static DEFINE_PER_CPU(struct cfs_rq, init_cfs_rq) ____cacheline_aligned_in_smp;
+
+static struct sched_entity *init_sched_entity_p[CONFIG_NR_CPUS];
+static struct cfs_rq *init_cfs_rq_p[CONFIG_NR_CPUS];
+
+/* Default task group.
+ * 	Every task in system belong to this group at bootup.
+ */
+static struct task_grp init_task_grp =  {
+					.se     = init_sched_entity_p,
+					.cfs_rq = init_cfs_rq_p,
+					};
+
+/* return group to which a task belongs */
+static inline struct task_grp *task_grp(struct task_struct *p)
+{
+	return container_of(task_subsys_state(p, cpu_subsys_id),
+				struct task_grp, css);
+}
+
+/* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
+static inline void set_task_cfs_rq(struct task_struct *p)
+{
+	p->se.cfs_rq = task_grp(p)->cfs_rq[task_cpu(p)];
+	p->se.parent = task_grp(p)->se[task_cpu(p)];
+}
+
+#else
+
+static inline void set_task_cfs_rq(struct task_struct *p) { }
+
+#endif	/* CONFIG_FAIR_GROUP_SCHED */
+
 /* CFS-related fields in a runqueue */
 struct cfs_rq {
 	struct load_weight load;
@@ -208,6 +260,7 @@ struct cfs_rq {
 	 * list is used during load balance.
 	 */
 	struct list_head leaf_cfs_rq_list; /* Better name : task_cfs_rq_list? */
+	struct task_grp *tg;    /* group that "owns" this runqueue */
 #endif
 };
 
@@ -405,18 +458,6 @@ unsigned long long cpu_clock(int cpu)
 
 EXPORT_SYMBOL_GPL(cpu_clock);
 
-#ifdef CONFIG_FAIR_GROUP_SCHED
-/* Change a task's ->cfs_rq if it moves across CPUs */
-static inline void set_task_cfs_rq(struct task_struct *p)
-{
-	p->se.cfs_rq = &task_rq(p)->cfs;
-}
-#else
-static inline void set_task_cfs_rq(struct task_struct *p)
-{
-}
-#endif
-
 #ifndef prepare_arch_switch
 # define prepare_arch_switch(next)	do { } while (0)
 #endif
@@ -3987,8 +4028,11 @@ void rt_mutex_setprio(struct task_struct
 
 	oldprio = p->prio;
 	on_rq = p->se.on_rq;
-	if (on_rq)
+	if (on_rq) {
 		dequeue_task(rq, p, 0);
+		if (task_running(rq, p))
+			p->sched_class->put_prev_task(rq, p);
+	}
 
 	if (rt_prio(prio))
 		p->sched_class = &rt_sched_class;
@@ -4007,6 +4051,7 @@ void rt_mutex_setprio(struct task_struct
 		if (task_running(rq, p)) {
 			if (p->prio > oldprio)
 				resched_task(rq->curr);
+			p->sched_class->set_curr_task(rq);
 		} else {
 			check_preempt_curr(rq, p);
 		}
@@ -4293,8 +4338,11 @@ recheck:
 	}
 	update_rq_clock(rq);
 	on_rq = p->se.on_rq;
-	if (on_rq)
+	if (on_rq) {
 		deactivate_task(rq, p, 0);
+		if (task_running(rq, p))
+			p->sched_class->put_prev_task(rq, p);
+	}
 	oldprio = p->prio;
 	__setscheduler(rq, p, policy, param->sched_priority);
 	if (on_rq) {
@@ -4307,6 +4355,7 @@ recheck:
 		if (task_running(rq, p)) {
 			if (p->prio > oldprio)
 				resched_task(rq->curr);
+			p->sched_class->set_curr_task(rq);
 		} else {
 			check_preempt_curr(rq, p);
 		}
@@ -6567,7 +6616,25 @@ void __init sched_init(void)
 		init_cfs_rq(&rq->cfs, rq);
 #ifdef CONFIG_FAIR_GROUP_SCHED
 		INIT_LIST_HEAD(&rq->leaf_cfs_rq_list);
-		list_add(&rq->cfs.leaf_cfs_rq_list, &rq->leaf_cfs_rq_list);
+	 	{
+ 			struct cfs_rq *cfs_rq = &per_cpu(init_cfs_rq, i);
+ 			struct sched_entity *se =
+ 					 &per_cpu(init_sched_entity, i);
+
+ 			init_cfs_rq_p[i] = cfs_rq;
+ 			init_cfs_rq(cfs_rq, rq);
+ 			cfs_rq->tg = &init_task_grp;
+ 			list_add(&cfs_rq->leaf_cfs_rq_list,
+							 &rq->leaf_cfs_rq_list);
+
+ 			init_sched_entity_p[i] = se;
+ 			se->cfs_rq = &rq->cfs;
+ 			se->my_q = cfs_rq;
+ 			se->load.weight = NICE_0_LOAD;
+			se->load.inv_weight = div64_64(1ULL<<32, NICE_0_LOAD);
+ 			se->parent = NULL;
+ 		}
+		init_task_grp.shares = NICE_0_LOAD;
 #endif
 		rq->ls.load_update_last = now;
 		rq->ls.load_update_start = now;
@@ -6764,3 +6831,250 @@ void set_curr_task(int cpu, struct task_
 }
 
 #endif
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+
+/* return corresponding task_grp object of a container */
+static inline struct task_grp *container_tg(struct container *cont)
+{
+	return container_of(container_subsys_state(cont, cpu_subsys_id),
+					 struct task_grp, css);
+}
+
+/* allocate runqueue etc for a new task group */
+static struct container_subsys_state *
+sched_create_group(struct container_subsys *ss, struct container *cont)
+{
+	struct task_grp *tg;
+	struct cfs_rq *cfs_rq;
+	struct sched_entity *se;
+	int i;
+
+	if (!cont->parent) {
+		/* This is early initialization for the top container */
+		init_task_grp.css.container = cont;
+		return &init_task_grp.css;
+	}
+
+	/* we support only 1-level deep hierarchical scheduler atm */
+	if (cont->parent->parent)
+		return ERR_PTR(-EINVAL);
+
+	tg = kzalloc(sizeof(*tg), GFP_KERNEL);
+	if (!tg)
+		return ERR_PTR(-ENOMEM);
+
+	tg->cfs_rq = kzalloc(sizeof(cfs_rq) * num_possible_cpus(), GFP_KERNEL);
+	if (!tg->cfs_rq)
+		goto err;
+	tg->se = kzalloc(sizeof(se) * num_possible_cpus(), GFP_KERNEL);
+	if (!tg->se)
+		goto err;
+
+	for_each_possible_cpu(i) {
+		struct rq *rq = cpu_rq(i);
+
+		cfs_rq = kmalloc_node(sizeof(struct cfs_rq), GFP_KERNEL,
+							 cpu_to_node(i));
+		if (!cfs_rq)
+			goto err;
+
+		se = kmalloc_node(sizeof(struct sched_entity), GFP_KERNEL,
+							cpu_to_node(i));
+		if (!se)
+			goto err;
+
+		memset(cfs_rq, 0, sizeof(struct cfs_rq));
+		memset(se, 0, sizeof(struct sched_entity));
+
+		tg->cfs_rq[i] = cfs_rq;
+		init_cfs_rq(cfs_rq, rq);
+		cfs_rq->tg = tg;
+		list_add_rcu(&cfs_rq->leaf_cfs_rq_list, &rq->leaf_cfs_rq_list);
+
+		tg->se[i] = se;
+		se->cfs_rq = &rq->cfs;
+		se->my_q = cfs_rq;
+		se->load.weight = NICE_0_LOAD;
+		se->load.inv_weight = div64_64(1ULL<<32, NICE_0_LOAD);
+		se->parent = NULL;
+	}
+
+	tg->shares = NICE_0_LOAD;
+
+	/* Bind the container to task_grp object we just created */
+	tg->css.container = cont;
+
+	return &tg->css;
+
+err:
+	for_each_possible_cpu(i) {
+		if (tg->cfs_rq && tg->cfs_rq[i])
+			kfree(tg->cfs_rq[i]);
+		if (tg->se && tg->se[i])
+
...

Re: [PATCH] Hookup group-scheduler with task container infrastructure [message #20257 is a reply to message #20218] Fri, 14 September 2007 09:41 Go to previous messageGo to next message
Ingo Molnar is currently offline  Ingo Molnar
Messages: 51
Registered: December 2005
Member
* Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> wrote:

> Add interface to control cpu bandwidth allocation to task-groups.

btw., just in case it was not obvious, i'll repeat my older assessment 
of your patch: the general picture approach looks good to me and the 
code is upstream-worthy.

( suggestion: if you want more people to test it then you might want to 
  do some add-on "put all users into separate groups" patch and .config 
  option - which could be tried without people having to know anything 
  about container setup. )

	Ingo
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Re: [PATCH] Hookup group-scheduler with task container infrastructure [message #20282 is a reply to message #20257] Fri, 14 September 2007 15:51 Go to previous messageGo to next message
Srivatsa Vaddagiri is currently offline  Srivatsa Vaddagiri
Messages: 241
Registered: August 2006
Senior Member
On Fri, Sep 14, 2007 at 11:41:58AM +0200, Ingo Molnar wrote:
> * Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> wrote:
> > Add interface to control cpu bandwidth allocation to task-groups.
> 
> btw., just in case it was not obvious, i'll repeat my older assessment 
> of your patch: the general picture approach looks good to me and the 
> code is upstream-worthy.

Thanks for the feedback!

> ( suggestion: if you want more people to test it then you might want to 
>   do some add-on "put all users into separate groups" patch and .config 
>   option - which could be tried without people having to know anything 
>   about container setup. )

I do want more people to test it and I agree that hooking onto
user-id based groups is the best way to get that done. How do we
implement that? I have two choices:

1. Do a kernel patch, as you suggest above, which defines task-groups
   based on user-id and hook that group definition with group scheduler.
   We need to provide some means for the admin to tune relative
   nice-value of each user (perhaps thr' sysctl?). 

   This user-id based grouping will have to be mutually exclusive with
   task-container based grouping. Hence we need to ensure that only one
   form of grouping is selected and not both at compile time.

2. Enable only one form of grouping, which is task-container based. Provide a 
   user-space daemon (attached) which can automatically put tasks of different 
   users in different task-containers. The daemon will need to be started at 
   early boot-time. It can also be extended to support a configuration file
   (ex: inittab) where cpu allocation for different users are specified.
   The fact that daemon is managing to provide fair allocation to users
   should be transparent.

   I hope that task-containers (aka cgroups) will go into 2.6.24, in which case 
   the second option seems to be more attractive to me.

I will neverthless try to work out Option 1, just to see how it looks.

--
Regards,
vatsa
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Re: [PATCH] Hookup group-scheduler with task container infrastructure [message #20286 is a reply to message #20282] Fri, 14 September 2007 16:13 Go to previous message
Srivatsa Vaddagiri is currently offline  Srivatsa Vaddagiri
Messages: 241
Registered: August 2006
Senior Member
On Fri, Sep 14, 2007 at 09:29:13PM +0530, Srivatsa Vaddagiri wrote:
> 2. Enable only one form of grouping, which is task-container based. Provide a 
>    user-space daemon (attached) which can automatically put tasks of different 
Oops ..forgot to attach. But I realize that I had already sent the
source for the daemon here:

	http://article.gmane.org/gmane.linux.kernel/553267

-- 
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vatsa
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