rcu: add tracing for RCU's kthread run states. (d71df90e) · Commits · e / devices / android_kernel_samsung_universal8895

kernel/rcutree.c

+10 −1

Original line number	Original line	Diff line number	Diff line
	@@ -91,8 +91,9 @@ EXPORT_SYMBOL_GPL(rcu_scheduler_active);
	* handle all flavors of RCU.		* handle all flavors of RCU.
	*/		*/
	static DEFINE_PER_CPU(struct task_struct *, rcu_cpu_kthread_task);		static DEFINE_PER_CPU(struct task_struct *, rcu_cpu_kthread_task);
			DEFINE_PER_CPU(unsigned int, rcu_cpu_kthread_status);
	static DEFINE_PER_CPU(wait_queue_head_t, rcu_cpu_wq);		static DEFINE_PER_CPU(wait_queue_head_t, rcu_cpu_wq);
	static DEFINE_PER_CPU(char, rcu_cpu_has_work);		DEFINE_PER_CPU(char, rcu_cpu_has_work);
	static char rcu_kthreads_spawnable;		static char rcu_kthreads_spawnable;

	static void rcu_node_kthread_setaffinity(struct rcu_node *rnp, int outgoingcpu);		static void rcu_node_kthread_setaffinity(struct rcu_node *rnp, int outgoingcpu);
	@@ -1563,11 +1564,13 @@ static int rcu_cpu_kthread(void *arg)
	int cpu = (int)(long)arg;		int cpu = (int)(long)arg;
	unsigned long flags;		unsigned long flags;
	int spincnt = 0;		int spincnt = 0;
			unsigned int *statusp = &per_cpu(rcu_cpu_kthread_status, cpu);
	wait_queue_head_t *wqp = &per_cpu(rcu_cpu_wq, cpu);		wait_queue_head_t *wqp = &per_cpu(rcu_cpu_wq, cpu);
	char work;		char work;
	char *workp = &per_cpu(rcu_cpu_has_work, cpu);		char *workp = &per_cpu(rcu_cpu_has_work, cpu);

	for (;;) {		for (;;) {
			*statusp = RCU_KTHREAD_WAITING;
	wait_event_interruptible(*wqp,		wait_event_interruptible(*wqp,
	*workp != 0 \|\| kthread_should_stop());		*workp != 0 \|\| kthread_should_stop());
	local_bh_disable();		local_bh_disable();
	@@ -1575,6 +1578,7 @@ static int rcu_cpu_kthread(void *arg)
	local_bh_enable();		local_bh_enable();
	break;		break;
	}		}
			*statusp = RCU_KTHREAD_RUNNING;
	local_irq_save(flags);		local_irq_save(flags);
	work = *workp;		work = *workp;
	*workp = 0;		*workp = 0;
	@@ -1587,10 +1591,12 @@ static int rcu_cpu_kthread(void *arg)
	else		else
	spincnt = 0;		spincnt = 0;
	if (spincnt > 10) {		if (spincnt > 10) {
			*statusp = RCU_KTHREAD_YIELDING;
	rcu_yield(rcu_cpu_kthread_timer, (unsigned long)cpu);		rcu_yield(rcu_cpu_kthread_timer, (unsigned long)cpu);
	spincnt = 0;		spincnt = 0;
	}		}
	}		}
			*statusp = RCU_KTHREAD_STOPPED;
	return 0;		return 0;
	}		}

	@@ -1637,10 +1643,12 @@ static int rcu_node_kthread(void *arg)
	struct task_struct *t;		struct task_struct *t;

	for (;;) {		for (;;) {
			rnp->node_kthread_status = RCU_KTHREAD_WAITING;
	wait_event_interruptible(rnp->node_wq, rnp->wakemask != 0 \|\|		wait_event_interruptible(rnp->node_wq, rnp->wakemask != 0 \|\|
	kthread_should_stop());		kthread_should_stop());
	if (kthread_should_stop())		if (kthread_should_stop())
	break;		break;
			rnp->node_kthread_status = RCU_KTHREAD_RUNNING;
	raw_spin_lock_irqsave(&rnp->lock, flags);		raw_spin_lock_irqsave(&rnp->lock, flags);
	mask = rnp->wakemask;		mask = rnp->wakemask;
	rnp->wakemask = 0;		rnp->wakemask = 0;
	@@ -1661,6 +1669,7 @@ static int rcu_node_kthread(void *arg)
	preempt_enable();		preempt_enable();
	}		}
	}		}
			rnp->node_kthread_status = RCU_KTHREAD_STOPPED;
	return 0;		return 0;
	}		}

kernel/rcutree.h

+11 −0

Original line number	Original line	Diff line number	Diff line
	@@ -89,6 +89,13 @@ struct rcu_dynticks {
	atomic_t dynticks; /* Even value for dynticks-idle, else odd. */		atomic_t dynticks; /* Even value for dynticks-idle, else odd. */
	};		};

			/* RCU's kthread states for tracing. */
			#define RCU_KTHREAD_STOPPED 0
			#define RCU_KTHREAD_RUNNING 1
			#define RCU_KTHREAD_WAITING 2
			#define RCU_KTHREAD_YIELDING 3
			#define RCU_KTHREAD_MAX 3

	/*		/*
	* Definition for node within the RCU grace-period-detection hierarchy.		* Definition for node within the RCU grace-period-detection hierarchy.
	*/		*/
	@@ -152,6 +159,8 @@ struct rcu_node {
	wait_queue_head_t boost_wq;		wait_queue_head_t boost_wq;
	/* Wait queue on which to park the boost */		/* Wait queue on which to park the boost */
	/* kthread. */		/* kthread. */
			unsigned int boost_kthread_status;
			/* State of boost_kthread_task for tracing. */
	unsigned long n_tasks_boosted;		unsigned long n_tasks_boosted;
	/* Total number of tasks boosted. */		/* Total number of tasks boosted. */
	unsigned long n_exp_boosts;		unsigned long n_exp_boosts;
	@@ -179,6 +188,8 @@ struct rcu_node {
	wait_queue_head_t node_wq;		wait_queue_head_t node_wq;
	/* Wait queue on which to park the per-node */		/* Wait queue on which to park the per-node */
	/* kthread. */		/* kthread. */
			unsigned int node_kthread_status;
			/* State of node_kthread_task for tracing. */
	} ____cacheline_internodealigned_in_smp;		} ____cacheline_internodealigned_in_smp;

	/*		/*

kernel/rcutree_plugin.h

+3 −0

Original line number	Original line	Diff line number	Diff line
	@@ -1198,11 +1198,13 @@ static int rcu_boost_kthread(void *arg)
	int more2boost;		int more2boost;

	for (;;) {		for (;;) {
			rnp->boost_kthread_status = RCU_KTHREAD_WAITING;
	wait_event_interruptible(rnp->boost_wq, rnp->boost_tasks \|\|		wait_event_interruptible(rnp->boost_wq, rnp->boost_tasks \|\|
	rnp->exp_tasks \|\|		rnp->exp_tasks \|\|
	kthread_should_stop());		kthread_should_stop());
	if (kthread_should_stop())		if (kthread_should_stop())
	break;		break;
			rnp->boost_kthread_status = RCU_KTHREAD_RUNNING;
	more2boost = rcu_boost(rnp);		more2boost = rcu_boost(rnp);
	if (more2boost)		if (more2boost)
	spincnt++;		spincnt++;
	@@ -1213,6 +1215,7 @@ static int rcu_boost_kthread(void *arg)
	spincnt = 0;		spincnt = 0;
	}		}
	}		}
			rnp->boost_kthread_status = RCU_KTHREAD_STOPPED;
	return 0;		return 0;
	}		}

kernel/rcutree_trace.c

+20 −3

Original line number	Original line	Diff line number	Diff line
	@@ -46,6 +46,16 @@
	#define RCU_TREE_NONCORE		#define RCU_TREE_NONCORE
	#include "rcutree.h"		#include "rcutree.h"

			DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_status);
			DECLARE_PER_CPU(char, rcu_cpu_has_work);

			static char convert_kthread_status(unsigned int kthread_status)
			{
			if (kthread_status > RCU_KTHREAD_MAX)
			return '?';
			return "SRWY"[kthread_status];
			}

	static void print_one_rcu_data(struct seq_file m, struct rcu_data rdp)		static void print_one_rcu_data(struct seq_file m, struct rcu_data rdp)
	{		{
	if (!rdp->beenonline)		if (!rdp->beenonline)
	@@ -64,7 +74,7 @@ static void print_one_rcu_data(struct seq_file m, struct rcu_data rdp)
	rdp->dynticks_fqs);		rdp->dynticks_fqs);
	#endif /* #ifdef CONFIG_NO_HZ */		#endif /* #ifdef CONFIG_NO_HZ */
	seq_printf(m, " of=%lu ri=%lu", rdp->offline_fqs, rdp->resched_ipi);		seq_printf(m, " of=%lu ri=%lu", rdp->offline_fqs, rdp->resched_ipi);
	seq_printf(m, " ql=%ld qs=%c%c%c%c b=%ld",		seq_printf(m, " ql=%ld qs=%c%c%c%c kt=%d/%c b=%ld",
	rdp->qlen,		rdp->qlen,
	".N"[rdp->nxttail[RCU_NEXT_READY_TAIL] !=		".N"[rdp->nxttail[RCU_NEXT_READY_TAIL] !=
	rdp->nxttail[RCU_NEXT_TAIL]],		rdp->nxttail[RCU_NEXT_TAIL]],
	@@ -73,6 +83,9 @@ static void print_one_rcu_data(struct seq_file m, struct rcu_data rdp)
	".W"[rdp->nxttail[RCU_DONE_TAIL] !=		".W"[rdp->nxttail[RCU_DONE_TAIL] !=
	rdp->nxttail[RCU_WAIT_TAIL]],		rdp->nxttail[RCU_WAIT_TAIL]],
	".D"[&rdp->nxtlist != rdp->nxttail[RCU_DONE_TAIL]],		".D"[&rdp->nxtlist != rdp->nxttail[RCU_DONE_TAIL]],
			per_cpu(rcu_cpu_has_work, rdp->cpu),
			convert_kthread_status(per_cpu(rcu_cpu_kthread_status,
			rdp->cpu)),
	rdp->blimit);		rdp->blimit);
	seq_printf(m, " ci=%lu co=%lu ca=%lu\n",		seq_printf(m, " ci=%lu co=%lu ca=%lu\n",
	rdp->n_cbs_invoked, rdp->n_cbs_orphaned, rdp->n_cbs_adopted);		rdp->n_cbs_invoked, rdp->n_cbs_orphaned, rdp->n_cbs_adopted);
	@@ -130,7 +143,7 @@ static void print_one_rcu_data_csv(struct seq_file m, struct rcu_data rdp)
	rdp->dynticks_fqs);		rdp->dynticks_fqs);
	#endif /* #ifdef CONFIG_NO_HZ */		#endif /* #ifdef CONFIG_NO_HZ */
	seq_printf(m, ",%lu,%lu", rdp->offline_fqs, rdp->resched_ipi);		seq_printf(m, ",%lu,%lu", rdp->offline_fqs, rdp->resched_ipi);
	seq_printf(m, ",%ld,\"%c%c%c%c\",%ld", rdp->qlen,		seq_printf(m, ",%ld,\"%c%c%c%c\",%d,\"%c\",%ld", rdp->qlen,
	".N"[rdp->nxttail[RCU_NEXT_READY_TAIL] !=		".N"[rdp->nxttail[RCU_NEXT_READY_TAIL] !=
	rdp->nxttail[RCU_NEXT_TAIL]],		rdp->nxttail[RCU_NEXT_TAIL]],
	".R"[rdp->nxttail[RCU_WAIT_TAIL] !=		".R"[rdp->nxttail[RCU_WAIT_TAIL] !=
	@@ -138,6 +151,9 @@ static void print_one_rcu_data_csv(struct seq_file m, struct rcu_data rdp)
	".W"[rdp->nxttail[RCU_DONE_TAIL] !=		".W"[rdp->nxttail[RCU_DONE_TAIL] !=
	rdp->nxttail[RCU_WAIT_TAIL]],		rdp->nxttail[RCU_WAIT_TAIL]],
	".D"[&rdp->nxtlist != rdp->nxttail[RCU_DONE_TAIL]],		".D"[&rdp->nxtlist != rdp->nxttail[RCU_DONE_TAIL]],
			per_cpu(rcu_cpu_has_work, rdp->cpu),
			convert_kthread_status(per_cpu(rcu_cpu_kthread_status,
			rdp->cpu)),
	rdp->blimit);		rdp->blimit);
	seq_printf(m, ",%lu,%lu,%lu\n",		seq_printf(m, ",%lu,%lu,%lu\n",
	rdp->n_cbs_invoked, rdp->n_cbs_orphaned, rdp->n_cbs_adopted);		rdp->n_cbs_invoked, rdp->n_cbs_orphaned, rdp->n_cbs_adopted);
	@@ -178,13 +194,14 @@ static const struct file_operations rcudata_csv_fops = {

	static void print_one_rcu_node_boost(struct seq_file m, struct rcu_node rnp)		static void print_one_rcu_node_boost(struct seq_file m, struct rcu_node rnp)
	{		{
	seq_printf(m, "%d:%d tasks=%c%c%c%c ntb=%lu neb=%lu nnb=%lu "		seq_printf(m, "%d:%d tasks=%c%c%c%c kt=%c ntb=%lu neb=%lu nnb=%lu "
	"j=%04x bt=%04x\n",		"j=%04x bt=%04x\n",
	rnp->grplo, rnp->grphi,		rnp->grplo, rnp->grphi,
	"T."[list_empty(&rnp->blkd_tasks)],		"T."[list_empty(&rnp->blkd_tasks)],
	"N."[!rnp->gp_tasks],		"N."[!rnp->gp_tasks],
	"E."[!rnp->exp_tasks],		"E."[!rnp->exp_tasks],
	"B."[!rnp->boost_tasks],		"B."[!rnp->boost_tasks],
			convert_kthread_status(rnp->boost_kthread_status),
	rnp->n_tasks_boosted, rnp->n_exp_boosts,		rnp->n_tasks_boosted, rnp->n_exp_boosts,
	rnp->n_normal_boosts,		rnp->n_normal_boosts,
	(int)(jiffies & 0xffff),		(int)(jiffies & 0xffff),