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Commit 5e1c12c3 authored by Pavankumar Kondeti's avatar Pavankumar Kondeti
Browse files

sched: Add a knob to disable the core_ctl 



The CPU hotplug tests does not work with core_ctl compiled
statically into kernel. Provide an interface to disable
the hotplug by core_ctl.

Change-Id: I61ea36332f21e8f456bdfba8b89dd4d148020b61
Signed-off-by: default avatarPavankumar Kondeti <pkondeti@codeaurora.org>
parent 9a997c11

kernel/sched/core_ctl.c

+39 −2
Original line number Diff line number Diff line
@@ -60,6 +60,7 @@ struct cpu_data { 
	struct task_struct *hotplug_thread;

	struct kobject kobj;

	struct list_head pending_lru;

	bool disabled;

};



static DEFINE_PER_CPU(struct cpu_data, cpu_state);
@@ -294,6 +295,9 @@ static ssize_t show_global_state(struct cpu_data *state, char *buf) 
					"\tAvail CPUs: %u\n", c->avail_cpus);

		count += snprintf(buf + count, PAGE_SIZE - count,

					"\tNeed CPUs: %u\n", c->need_cpus);

		count += snprintf(buf + count, PAGE_SIZE - count,

					"\tStatus: %s\n",

					c->disabled ? "disabled" : "enabled");

	}



	return count;
@@ -340,6 +344,33 @@ static ssize_t show_not_preferred(struct cpu_data *state, char *buf) 
	return count;

}



static ssize_t store_disable(struct cpu_data *state,

				const char *buf, size_t count)

{

	unsigned int val;



	if (sscanf(buf, "%u\n", &val) != 1)

		return -EINVAL;



	val = !!val;



	if (state->disabled == val)

		return count;



	state->disabled = val;



	if (!state->disabled)

		wake_up_hotplug_thread(state);





	return count;

}



static ssize_t show_disable(struct cpu_data *state, char *buf)

{

	return snprintf(buf, PAGE_SIZE, "%u\n", state->disabled);

}



struct core_ctl_attr {

	struct attribute attr;

	ssize_t (*show)(struct cpu_data *, char *);
@@ -366,6 +397,7 @@ core_ctl_attr_ro(need_cpus); 
core_ctl_attr_ro(online_cpus);

core_ctl_attr_ro(global_state);

core_ctl_attr_rw(not_preferred);

core_ctl_attr_rw(disable);



static struct attribute *default_attrs[] = {

	&min_cpus.attr,
@@ -380,6 +412,7 @@ static struct attribute *default_attrs[] = { 
	&online_cpus.attr,

	&global_state.attr,

	&not_preferred.attr,

	&disable.attr,

	NULL

};
@@ -624,6 +657,9 @@ static void wake_up_hotplug_thread(struct cpu_data *state) 
	struct cpu_data *pcpu;

	bool no_wakeup = false;



	if (unlikely(state->disabled))

		return;



	for_each_possible_cpu(cpu) {

		pcpu = &per_cpu(cpu_state, cpu);

		if (cpu != pcpu->first_cpu)
@@ -652,7 +688,7 @@ static void core_ctl_timer_func(unsigned long cpu) 
	struct cpu_data *state = &per_cpu(cpu_state, cpu);

	unsigned long flags;



	if (eval_need(state)) {

	if (eval_need(state) && !state->disabled) {

		spin_lock_irqsave(&state->pending_lock, flags);

		state->pending = true;

		spin_unlock_irqrestore(&state->pending_lock, flags);
@@ -866,7 +902,8 @@ static int __ref cpu_callback(struct notifier_block *nfb, 
		 * so that there's no race with hotplug thread bringing up more

		 * CPUs than necessary.

		 */

		if (apply_limits(f, f->need_cpus) <= f->online_cpus) {

		if (!f->disabled &&

			apply_limits(f, f->need_cpus) <= f->online_cpus) {

			pr_debug("Prevent CPU%d onlining\n", cpu);

			ret = NOTIFY_BAD;

		} else {