Commit 76d12132 authored by Joel Fernandes's avatar Joel Fernandes Committed by Peter Zijlstra
Browse files

sched/debug: Add support to change sched_ext server params 



When a sched_ext server is loaded, tasks in the fair class are
automatically moved to the sched_ext class. Add support to modify the
ext server parameters similar to how the fair server parameters are
modified.

Re-use common code between ext and fair servers as needed.

Co-developed-by: default avatarAndrea Righi <arighi@nvidia.com>
Signed-off-by: default avatarAndrea Righi <arighi@nvidia.com>
Signed-off-by: default avatarJoel Fernandes <joelagnelf@nvidia.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: default avatarJuri Lelli <juri.lelli@redhat.com>
Tested-by: default avatarChristian Loehle <christian.loehle@arm.com>
Link: https://patch.msgid.link/20260126100050.3854740-6-arighi@nvidia.com
parent cd959a35

kernel/sched/debug.c

+133 −24
Original line number Diff line number Diff line
@@ -330,14 +330,16 @@ enum dl_param { 
	DL_PERIOD,

};



static unsigned long fair_server_period_max = (1UL << 22) * NSEC_PER_USEC; /* ~4 seconds */

static unsigned long fair_server_period_min = (100) * NSEC_PER_USEC;     /* 100 us */

static unsigned long dl_server_period_max = (1UL << 22) * NSEC_PER_USEC; /* ~4 seconds */

static unsigned long dl_server_period_min = (100) * NSEC_PER_USEC;     /* 100 us */



static ssize_t sched_fair_server_write(struct file *filp, const char __user *ubuf,

				       size_t cnt, loff_t *ppos, enum dl_param param)

static ssize_t sched_server_write_common(struct file *filp, const char __user *ubuf,

					 size_t cnt, loff_t *ppos, enum dl_param param,

					 void *server)

{

	long cpu = (long) ((struct seq_file *) filp->private_data)->private;

	struct rq *rq = cpu_rq(cpu);

	struct sched_dl_entity *dl_se = (struct sched_dl_entity *)server;

	u64 runtime, period;

	int retval = 0;

	size_t err;
@@ -350,8 +352,8 @@ static ssize_t sched_fair_server_write(struct file *filp, const char __user *ubu 
	scoped_guard (rq_lock_irqsave, rq) {

		bool is_active;



		runtime  = rq->fair_server.dl_runtime;

		period = rq->fair_server.dl_period;

		runtime = dl_se->dl_runtime;

		period = dl_se->dl_period;



		switch (param) {

		case DL_RUNTIME:
@@ -367,25 +369,25 @@ static ssize_t sched_fair_server_write(struct file *filp, const char __user *ubu 
		}



		if (runtime > period ||

		    period > fair_server_period_max ||

		    period < fair_server_period_min) {

		    period > dl_server_period_max ||

		    period < dl_server_period_min) {

			return  -EINVAL;

		}



		is_active = dl_server_active(&rq->fair_server);

		is_active = dl_server_active(dl_se);

		if (is_active) {

			update_rq_clock(rq);

			dl_server_stop(&rq->fair_server);

			dl_server_stop(dl_se);

		}



		retval = dl_server_apply_params(&rq->fair_server, runtime, period, 0);

		retval = dl_server_apply_params(dl_se, runtime, period, 0);



		if (!runtime)

			printk_deferred("Fair server disabled in CPU %d, system may crash due to starvation.\n",

					cpu_of(rq));

			printk_deferred("%s server disabled in CPU %d, system may crash due to starvation.\n",

					server == &rq->fair_server ? "Fair" : "Ext", cpu_of(rq));



		if (is_active && runtime)

			dl_server_start(&rq->fair_server);

			dl_server_start(dl_se);



		if (retval < 0)

			return retval;
@@ -395,36 +397,42 @@ static ssize_t sched_fair_server_write(struct file *filp, const char __user *ubu 
	return cnt;

}



static size_t sched_fair_server_show(struct seq_file *m, void *v, enum dl_param param)

static size_t sched_server_show_common(struct seq_file *m, void *v, enum dl_param param,

				       void *server)

{

	unsigned long cpu = (unsigned long) m->private;

	struct rq *rq = cpu_rq(cpu);

	struct sched_dl_entity *dl_se = (struct sched_dl_entity *)server;

	u64 value;



	switch (param) {

	case DL_RUNTIME:

		value = rq->fair_server.dl_runtime;

		value = dl_se->dl_runtime;

		break;

	case DL_PERIOD:

		value = rq->fair_server.dl_period;

		value = dl_se->dl_period;

		break;

	}



	seq_printf(m, "%llu\n", value);

	return 0;



}



static ssize_t

sched_fair_server_runtime_write(struct file *filp, const char __user *ubuf,

				size_t cnt, loff_t *ppos)

{

	return sched_fair_server_write(filp, ubuf, cnt, ppos, DL_RUNTIME);

	long cpu = (long) ((struct seq_file *) filp->private_data)->private;

	struct rq *rq = cpu_rq(cpu);



	return sched_server_write_common(filp, ubuf, cnt, ppos, DL_RUNTIME,

					&rq->fair_server);

}



static int sched_fair_server_runtime_show(struct seq_file *m, void *v)

{

	return sched_fair_server_show(m, v, DL_RUNTIME);

	unsigned long cpu = (unsigned long) m->private;

	struct rq *rq = cpu_rq(cpu);



	return sched_server_show_common(m, v, DL_RUNTIME, &rq->fair_server);

}



static int sched_fair_server_runtime_open(struct inode *inode, struct file *filp)
@@ -440,16 +448,57 @@ static const struct file_operations fair_server_runtime_fops = { 
	.release	= single_release,

};



#ifdef CONFIG_SCHED_CLASS_EXT

static ssize_t

sched_ext_server_runtime_write(struct file *filp, const char __user *ubuf,

			       size_t cnt, loff_t *ppos)

{

	long cpu = (long) ((struct seq_file *) filp->private_data)->private;

	struct rq *rq = cpu_rq(cpu);



	return sched_server_write_common(filp, ubuf, cnt, ppos, DL_RUNTIME,

					&rq->ext_server);

}



static int sched_ext_server_runtime_show(struct seq_file *m, void *v)

{

	unsigned long cpu = (unsigned long) m->private;

	struct rq *rq = cpu_rq(cpu);



	return sched_server_show_common(m, v, DL_RUNTIME, &rq->ext_server);

}



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

{

	return single_open(filp, sched_ext_server_runtime_show, inode->i_private);

}



static const struct file_operations ext_server_runtime_fops = {

	.open		= sched_ext_server_runtime_open,

	.write		= sched_ext_server_runtime_write,

	.read		= seq_read,

	.llseek		= seq_lseek,

	.release	= single_release,

};

#endif /* CONFIG_SCHED_CLASS_EXT */



static ssize_t

sched_fair_server_period_write(struct file *filp, const char __user *ubuf,

			       size_t cnt, loff_t *ppos)

{

	return sched_fair_server_write(filp, ubuf, cnt, ppos, DL_PERIOD);

	long cpu = (long) ((struct seq_file *) filp->private_data)->private;

	struct rq *rq = cpu_rq(cpu);



	return sched_server_write_common(filp, ubuf, cnt, ppos, DL_PERIOD,

					&rq->fair_server);

}



static int sched_fair_server_period_show(struct seq_file *m, void *v)

{

	return sched_fair_server_show(m, v, DL_PERIOD);

	unsigned long cpu = (unsigned long) m->private;

	struct rq *rq = cpu_rq(cpu);



	return sched_server_show_common(m, v, DL_PERIOD, &rq->fair_server);

}



static int sched_fair_server_period_open(struct inode *inode, struct file *filp)
@@ -465,6 +514,40 @@ static const struct file_operations fair_server_period_fops = { 
	.release	= single_release,

};



#ifdef CONFIG_SCHED_CLASS_EXT

static ssize_t

sched_ext_server_period_write(struct file *filp, const char __user *ubuf,

			      size_t cnt, loff_t *ppos)

{

	long cpu = (long) ((struct seq_file *) filp->private_data)->private;

	struct rq *rq = cpu_rq(cpu);



	return sched_server_write_common(filp, ubuf, cnt, ppos, DL_PERIOD,

					&rq->ext_server);

}



static int sched_ext_server_period_show(struct seq_file *m, void *v)

{

	unsigned long cpu = (unsigned long) m->private;

	struct rq *rq = cpu_rq(cpu);



	return sched_server_show_common(m, v, DL_PERIOD, &rq->ext_server);

}



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

{

	return single_open(filp, sched_ext_server_period_show, inode->i_private);

}



static const struct file_operations ext_server_period_fops = {

	.open		= sched_ext_server_period_open,

	.write		= sched_ext_server_period_write,

	.read		= seq_read,

	.llseek		= seq_lseek,

	.release	= single_release,

};

#endif /* CONFIG_SCHED_CLASS_EXT */



static struct dentry *debugfs_sched;



static void debugfs_fair_server_init(void)
@@ -488,6 +571,29 @@ static void debugfs_fair_server_init(void) 
	}

}



#ifdef CONFIG_SCHED_CLASS_EXT

static void debugfs_ext_server_init(void)

{

	struct dentry *d_ext;

	unsigned long cpu;



	d_ext = debugfs_create_dir("ext_server", debugfs_sched);

	if (!d_ext)

		return;



	for_each_possible_cpu(cpu) {

		struct dentry *d_cpu;

		char buf[32];



		snprintf(buf, sizeof(buf), "cpu%lu", cpu);

		d_cpu = debugfs_create_dir(buf, d_ext);



		debugfs_create_file("runtime", 0644, d_cpu, (void *) cpu, &ext_server_runtime_fops);

		debugfs_create_file("period", 0644, d_cpu, (void *) cpu, &ext_server_period_fops);

	}

}

#endif /* CONFIG_SCHED_CLASS_EXT */



static __init int sched_init_debug(void)

{

	struct dentry __maybe_unused *numa;
@@ -526,6 +632,9 @@ static __init int sched_init_debug(void) 
	debugfs_create_file("debug", 0444, debugfs_sched, NULL, &sched_debug_fops);



	debugfs_fair_server_init();

#ifdef CONFIG_SCHED_CLASS_EXT

	debugfs_ext_server_init();

#endif



	return 0;

}