diff options
| -rw-r--r-- | kernel/rcutree.h | 19 | ||||
| -rw-r--r-- | kernel/rcutree_plugin.h | 42 | ||||
| -rw-r--r-- | kernel/rcutree_trace.c | 68 |
3 files changed, 125 insertions, 4 deletions
diff --git a/kernel/rcutree.h b/kernel/rcutree.h index 8db0cdc7f450..d49046c79c59 100644 --- a/kernel/rcutree.h +++ b/kernel/rcutree.h @@ -152,6 +152,25 @@ struct rcu_node { wait_queue_head_t boost_wq; /* Wait queue on which to park the boost */ /* kthread. */ + unsigned long n_tasks_boosted; + /* Total number of tasks boosted. */ + unsigned long n_exp_boosts; + /* Number of tasks boosted for expedited GP. */ + unsigned long n_normal_boosts; + /* Number of tasks boosted for normal GP. */ + unsigned long n_balk_blkd_tasks; + /* Refused to boost: no blocked tasks. */ + unsigned long n_balk_exp_gp_tasks; + /* Refused to boost: nothing blocking GP. */ + unsigned long n_balk_boost_tasks; + /* Refused to boost: already boosting. */ + unsigned long n_balk_notblocked; + /* Refused to boost: RCU RS CS still running. */ + unsigned long n_balk_notyet; + /* Refused to boost: not yet time. */ + unsigned long n_balk_nos; + /* Refused to boost: not sure why, though. */ + /* This can happen due to race conditions. */ #endif /* #ifdef CONFIG_RCU_BOOST */ struct task_struct *node_kthread_task; /* kthread that takes care of this rcu_node */ diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index 4e486255df63..07d346445d12 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -1073,6 +1073,33 @@ static void __init __rcu_init_preempt(void) #include "rtmutex_common.h" +#ifdef CONFIG_RCU_TRACE + +static void rcu_initiate_boost_trace(struct rcu_node *rnp) +{ + if (list_empty(&rnp->blkd_tasks)) + rnp->n_balk_blkd_tasks++; + else if (rnp->exp_tasks == NULL && rnp->gp_tasks == NULL) + rnp->n_balk_exp_gp_tasks++; + else if (rnp->gp_tasks != NULL && rnp->boost_tasks != NULL) + rnp->n_balk_boost_tasks++; + else if (rnp->gp_tasks != NULL && rnp->qsmask != 0) + rnp->n_balk_notblocked++; + else if (rnp->gp_tasks != NULL && + ULONG_CMP_GE(jiffies, rnp->boost_time)) + rnp->n_balk_notyet++; + else + rnp->n_balk_nos++; +} + +#else /* #ifdef CONFIG_RCU_TRACE */ + +static void rcu_initiate_boost_trace(struct rcu_node *rnp) +{ +} + +#endif /* #else #ifdef CONFIG_RCU_TRACE */ + /* * Carry out RCU priority boosting on the task indicated by ->exp_tasks * or ->boost_tasks, advancing the pointer to the next task in the @@ -1108,10 +1135,14 @@ static int rcu_boost(struct rcu_node *rnp) * expedited grace period must boost all blocked tasks, including * those blocking the pre-existing normal grace period. */ - if (rnp->exp_tasks != NULL) + if (rnp->exp_tasks != NULL) { tb = rnp->exp_tasks; - else + rnp->n_exp_boosts++; + } else { tb = rnp->boost_tasks; + rnp->n_normal_boosts++; + } + rnp->n_tasks_boosted++; /* * We boost task t by manufacturing an rt_mutex that appears to @@ -1197,8 +1228,10 @@ static void rcu_initiate_boost(struct rcu_node *rnp) { struct task_struct *t; - if (!rcu_preempt_blocked_readers_cgp(rnp) && rnp->exp_tasks == NULL) + if (!rcu_preempt_blocked_readers_cgp(rnp) && rnp->exp_tasks == NULL) { + rnp->n_balk_exp_gp_tasks++; return; + } if (rnp->exp_tasks != NULL || (rnp->gp_tasks != NULL && rnp->boost_tasks == NULL && @@ -1209,7 +1242,8 @@ static void rcu_initiate_boost(struct rcu_node *rnp) t = rnp->boost_kthread_task; if (t != NULL) wake_up_process(t); - } + } else + rcu_initiate_boost_trace(rnp); } /* diff --git a/kernel/rcutree_trace.c b/kernel/rcutree_trace.c index 1cedf94e2c4f..ead5736f99b5 100644 --- a/kernel/rcutree_trace.c +++ b/kernel/rcutree_trace.c @@ -157,6 +157,71 @@ static const struct file_operations rcudata_csv_fops = { .release = single_release, }; +#ifdef CONFIG_RCU_BOOST + +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 " + "j=%04x bt=%04x\n", + rnp->grplo, rnp->grphi, + "T."[list_empty(&rnp->blkd_tasks)], + "N."[!rnp->gp_tasks], + "E."[!rnp->exp_tasks], + "B."[!rnp->boost_tasks], + rnp->n_tasks_boosted, rnp->n_exp_boosts, + rnp->n_normal_boosts, + (int)(jiffies & 0xffff), + (int)(rnp->boost_time & 0xffff)); + seq_printf(m, "%s: nt=%lu egt=%lu bt=%lu nb=%lu ny=%lu nos=%lu\n", + " balk", + rnp->n_balk_blkd_tasks, + rnp->n_balk_exp_gp_tasks, + rnp->n_balk_boost_tasks, + rnp->n_balk_notblocked, + rnp->n_balk_notyet, + rnp->n_balk_nos); +} + +static int show_rcu_node_boost(struct seq_file *m, void *unused) +{ + struct rcu_node *rnp; + + rcu_for_each_leaf_node(&rcu_preempt_state, rnp) + print_one_rcu_node_boost(m, rnp); + return 0; +} + +static int rcu_node_boost_open(struct inode *inode, struct file *file) +{ + return single_open(file, show_rcu_node_boost, NULL); +} + +static const struct file_operations rcu_node_boost_fops = { + .owner = THIS_MODULE, + .open = rcu_node_boost_open, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; + +/* + * Create the rcuboost debugfs entry. Standard error return. + */ +static int rcu_boost_trace_create_file(struct dentry *rcudir) +{ + return !debugfs_create_file("rcuboost", 0444, rcudir, NULL, + &rcu_node_boost_fops); +} + +#else /* #ifdef CONFIG_RCU_BOOST */ + +static int rcu_boost_trace_create_file(struct dentry *rcudir) +{ + return 0; /* There cannot be an error if we didn't create it! */ +} + +#endif /* #else #ifdef CONFIG_RCU_BOOST */ + static void print_one_rcu_state(struct seq_file *m, struct rcu_state *rsp) { unsigned long gpnum; @@ -315,6 +380,9 @@ static int __init rcutree_trace_init(void) if (!retval) goto free_out; + if (rcu_boost_trace_create_file(rcudir)) + goto free_out; + retval = debugfs_create_file("rcugp", 0444, rcudir, NULL, &rcugp_fops); if (!retval) goto free_out; |