Commit 24e377a8 authored by Srivatsa Vaddagiri's avatar Srivatsa Vaddagiri Committed by Ingo Molnar
Browse files

sched: add fair-user scheduler 



Enable user-id based fair group scheduling. This is useful for anyone
who wants to test the group scheduler w/o having to enable
CONFIG_CGROUPS.

A separate scheduling group (i.e struct task_grp) is automatically created for 
every new user added to the system. Upon uid change for a task, it is made to 
move to the corresponding scheduling group.

A /proc tunable (/proc/root_user_share) is also provided to tune root
user's quota of cpu bandwidth.

Signed-off-by: default avatarSrivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Signed-off-by: default avatarDhaval Giani <dhaval@linux.vnet.ibm.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 9b5b7751

include/linux/sched.h

+4 −0
Original line number Original line Diff line number Diff line
@@ -597,6 +597,10 @@ struct user_struct { 
	/* Hash table maintenance information */

	/* Hash table maintenance information */

	struct hlist_node uidhash_node;

	struct hlist_node uidhash_node;

	uid_t uid;

	uid_t uid;



#ifdef CONFIG_FAIR_USER_SCHED

	struct task_grp *tg;

#endif

};

};





extern struct user_struct *find_user(uid_t);

extern struct user_struct *find_user(uid_t);

init/Kconfig

+13 −0
Original line number Original line Diff line number Diff line
@@ -289,6 +289,19 @@ config FAIR_GROUP_SCHED 
	  This feature lets cpu scheduler recognize task groups and control cpu

	  This feature lets cpu scheduler recognize task groups and control cpu

	  bandwidth allocation to such task groups.

	  bandwidth allocation to such task groups.





choice

	depends on FAIR_GROUP_SCHED

	prompt "Basis for grouping tasks"

	default FAIR_USER_SCHED



 	config FAIR_USER_SCHED

 		bool "user id"

 		help

 		  This option will choose userid as the basis for grouping

		  tasks, thus providing equal cpu bandwidth to each user.



endchoice



config SYSFS_DEPRECATED

config SYSFS_DEPRECATED

	bool "Create deprecated sysfs files"

	bool "Create deprecated sysfs files"

	default y

	default y

kernel/sched.c

+9 −0
Original line number Original line Diff line number Diff line
@@ -200,7 +200,12 @@ struct task_grp init_task_grp = { 
				.cfs_rq = init_cfs_rq_p,

				.cfs_rq = init_cfs_rq_p,

				 };

				 };





#ifdef CONFIG_FAIR_USER_SCHED

#define INIT_TASK_GRP_LOAD	2*NICE_0_LOAD

#else

#define INIT_TASK_GRP_LOAD	NICE_0_LOAD

#define INIT_TASK_GRP_LOAD	NICE_0_LOAD

#endif



static int init_task_grp_load = INIT_TASK_GRP_LOAD;

static int init_task_grp_load = INIT_TASK_GRP_LOAD;





/* return group to which a task belongs */

/* return group to which a task belongs */
@@ -208,7 +213,11 @@ static inline struct task_grp *task_grp(struct task_struct *p) 
{

{

	struct task_grp *tg;

	struct task_grp *tg;





#ifdef CONFIG_FAIR_USER_SCHED

	tg = p->user->tg;

#else

	tg  = &init_task_grp;

	tg  = &init_task_grp;

#endif





	return tg;

	return tg;

}

}

kernel/sched_debug.c

+52 −0
Original line number Original line Diff line number Diff line
@@ -212,6 +212,49 @@ static void sysrq_sched_debug_show(void) 
	sched_debug_show(NULL, NULL);

	sched_debug_show(NULL, NULL);

}

}





#ifdef CONFIG_FAIR_USER_SCHED



static DEFINE_MUTEX(root_user_share_mutex);



static int

root_user_share_read_proc(char *page, char **start, off_t off, int count,

				 int *eof, void *data)

{

	int len;



	len = sprintf(page, "%d\n", init_task_grp_load);



	return len;

}



static int

root_user_share_write_proc(struct file *file, const char __user *buffer,

				 unsigned long count, void *data)

{

	unsigned long shares;

	char kbuf[sizeof(unsigned long)+1];

	int rc = 0;



	if (copy_from_user(kbuf, buffer, sizeof(kbuf)))

		return -EFAULT;



	shares = simple_strtoul(kbuf, NULL, 0);



	if (!shares)

		shares = NICE_0_LOAD;



	mutex_lock(&root_user_share_mutex);



	init_task_grp_load = shares;

	rc = sched_group_set_shares(&init_task_grp, shares);



	mutex_unlock(&root_user_share_mutex);



	return (rc < 0 ? rc : count);

}



#endif	/* CONFIG_FAIR_USER_SCHED */



static int sched_debug_open(struct inode *inode, struct file *filp)

static int sched_debug_open(struct inode *inode, struct file *filp)

{

{

	return single_open(filp, sched_debug_show, NULL);

	return single_open(filp, sched_debug_show, NULL);
@@ -234,6 +277,15 @@ static int __init init_sched_debug_procfs(void) 




	pe->proc_fops = &sched_debug_fops;

	pe->proc_fops = &sched_debug_fops;





#ifdef CONFIG_FAIR_USER_SCHED

	pe = create_proc_entry("root_user_share", 0644, NULL);

	if (!pe)

		return -ENOMEM;



	pe->read_proc = root_user_share_read_proc;

	pe->write_proc = root_user_share_write_proc;

#endif



	return 0;

	return 0;

}

}

kernel/user.c

+43 −0
Original line number Original line Diff line number Diff line
@@ -50,8 +50,41 @@ struct user_struct root_user = { 
	.uid_keyring	= &root_user_keyring,

	.uid_keyring	= &root_user_keyring,

	.session_keyring = &root_session_keyring,

	.session_keyring = &root_session_keyring,

#endif

#endif

#ifdef CONFIG_FAIR_USER_SCHED

	.tg		= &init_task_grp,

#endif

};

};





#ifdef CONFIG_FAIR_USER_SCHED

static void sched_destroy_user(struct user_struct *up)

{

	sched_destroy_group(up->tg);

}



static int sched_create_user(struct user_struct *up)

{

	int rc = 0;



	up->tg = sched_create_group();

	if (IS_ERR(up->tg))

		rc = -ENOMEM;



	return rc;

}



static void sched_switch_user(struct task_struct *p)

{

	sched_move_task(p);

}



#else	/* CONFIG_FAIR_USER_SCHED */



static void sched_destroy_user(struct user_struct *up) { }

static int sched_create_user(struct user_struct *up) { return 0; }

static void sched_switch_user(struct task_struct *p) { }



#endif	/* CONFIG_FAIR_USER_SCHED */



/*

/*

 * These routines must be called with the uidhash spinlock held!

 * These routines must be called with the uidhash spinlock held!

 */

 */
@@ -109,6 +142,7 @@ void free_uid(struct user_struct *up) 
	if (atomic_dec_and_lock(&up->__count, &uidhash_lock)) {

	if (atomic_dec_and_lock(&up->__count, &uidhash_lock)) {

		uid_hash_remove(up);

		uid_hash_remove(up);

		spin_unlock_irqrestore(&uidhash_lock, flags);

		spin_unlock_irqrestore(&uidhash_lock, flags);

		sched_destroy_user(up);

		key_put(up->uid_keyring);

		key_put(up->uid_keyring);

		key_put(up->session_keyring);

		key_put(up->session_keyring);

		kmem_cache_free(uid_cachep, up);

		kmem_cache_free(uid_cachep, up);
@@ -150,6 +184,13 @@ struct user_struct * alloc_uid(struct user_namespace *ns, uid_t uid) 
			return NULL;

			return NULL;

		}

		}





		if (sched_create_user(new) < 0) {

			key_put(new->uid_keyring);

			key_put(new->session_keyring);

			kmem_cache_free(uid_cachep, new);

			return NULL;

		}



		/*

		/*

		 * Before adding this, check whether we raced

		 * Before adding this, check whether we raced

		 * on adding the same user already..

		 * on adding the same user already..
@@ -157,6 +198,7 @@ struct user_struct * alloc_uid(struct user_namespace *ns, uid_t uid) 
		spin_lock_irq(&uidhash_lock);

		spin_lock_irq(&uidhash_lock);

		up = uid_hash_find(uid, hashent);

		up = uid_hash_find(uid, hashent);

		if (up) {

		if (up) {

			sched_destroy_user(new);

			key_put(new->uid_keyring);

			key_put(new->uid_keyring);

			key_put(new->session_keyring);

			key_put(new->session_keyring);

			kmem_cache_free(uid_cachep, new);

			kmem_cache_free(uid_cachep, new);
@@ -184,6 +226,7 @@ void switch_uid(struct user_struct *new_user) 
	atomic_dec(&old_user->processes);

	atomic_dec(&old_user->processes);

	switch_uid_keyring(new_user);

	switch_uid_keyring(new_user);

	current->user = new_user;

	current->user = new_user;

	sched_switch_user(current);





	/*

	/*

	 * We need to synchronize with __sigqueue_alloc()

	 * We need to synchronize with __sigqueue_alloc()