diff options
Diffstat (limited to 'kernel/rcutree.h')
| -rw-r--r-- | kernel/rcutree.h | 165 |
1 files changed, 113 insertions, 52 deletions
diff --git a/kernel/rcutree.h b/kernel/rcutree.h index 91d4170c5c13..257664815d5d 100644 --- a/kernel/rcutree.h +++ b/kernel/rcutree.h @@ -31,46 +31,51 @@ /* * Define shape of hierarchy based on NR_CPUS and CONFIG_RCU_FANOUT. * In theory, it should be possible to add more levels straightforwardly. - * In practice, this has not been tested, so there is probably some - * bug somewhere. + * In practice, this did work well going from three levels to four. + * Of course, your mileage may vary. */ #define MAX_RCU_LVLS 4 -#define RCU_FANOUT (CONFIG_RCU_FANOUT) -#define RCU_FANOUT_SQ (RCU_FANOUT * RCU_FANOUT) -#define RCU_FANOUT_CUBE (RCU_FANOUT_SQ * RCU_FANOUT) -#define RCU_FANOUT_FOURTH (RCU_FANOUT_CUBE * RCU_FANOUT) - -#if NR_CPUS <= RCU_FANOUT +#if CONFIG_RCU_FANOUT > 16 +#define RCU_FANOUT_LEAF 16 +#else /* #if CONFIG_RCU_FANOUT > 16 */ +#define RCU_FANOUT_LEAF (CONFIG_RCU_FANOUT) +#endif /* #else #if CONFIG_RCU_FANOUT > 16 */ +#define RCU_FANOUT_1 (RCU_FANOUT_LEAF) +#define RCU_FANOUT_2 (RCU_FANOUT_1 * CONFIG_RCU_FANOUT) +#define RCU_FANOUT_3 (RCU_FANOUT_2 * CONFIG_RCU_FANOUT) +#define RCU_FANOUT_4 (RCU_FANOUT_3 * CONFIG_RCU_FANOUT) + +#if NR_CPUS <= RCU_FANOUT_1 # define NUM_RCU_LVLS 1 # define NUM_RCU_LVL_0 1 # define NUM_RCU_LVL_1 (NR_CPUS) # define NUM_RCU_LVL_2 0 # define NUM_RCU_LVL_3 0 # define NUM_RCU_LVL_4 0 -#elif NR_CPUS <= RCU_FANOUT_SQ +#elif NR_CPUS <= RCU_FANOUT_2 # define NUM_RCU_LVLS 2 # define NUM_RCU_LVL_0 1 -# define NUM_RCU_LVL_1 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT) +# define NUM_RCU_LVL_1 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_1) # define NUM_RCU_LVL_2 (NR_CPUS) # define NUM_RCU_LVL_3 0 # define NUM_RCU_LVL_4 0 -#elif NR_CPUS <= RCU_FANOUT_CUBE +#elif NR_CPUS <= RCU_FANOUT_3 # define NUM_RCU_LVLS 3 # define NUM_RCU_LVL_0 1 -# define NUM_RCU_LVL_1 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_SQ) -# define NUM_RCU_LVL_2 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT) -# define NUM_RCU_LVL_3 NR_CPUS +# define NUM_RCU_LVL_1 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_2) +# define NUM_RCU_LVL_2 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_1) +# define NUM_RCU_LVL_3 (NR_CPUS) # define NUM_RCU_LVL_4 0 -#elif NR_CPUS <= RCU_FANOUT_FOURTH +#elif NR_CPUS <= RCU_FANOUT_4 # define NUM_RCU_LVLS 4 # define NUM_RCU_LVL_0 1 -# define NUM_RCU_LVL_1 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_CUBE) -# define NUM_RCU_LVL_2 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_SQ) -# define NUM_RCU_LVL_3 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT) -# define NUM_RCU_LVL_4 NR_CPUS +# define NUM_RCU_LVL_1 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_3) +# define NUM_RCU_LVL_2 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_2) +# define NUM_RCU_LVL_3 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_1) +# define NUM_RCU_LVL_4 (NR_CPUS) #else # error "CONFIG_RCU_FANOUT insufficient for NR_CPUS" -#endif /* #if (NR_CPUS) <= RCU_FANOUT */ +#endif /* #if (NR_CPUS) <= RCU_FANOUT_1 */ #define RCU_SUM (NUM_RCU_LVL_0 + NUM_RCU_LVL_1 + NUM_RCU_LVL_2 + NUM_RCU_LVL_3 + NUM_RCU_LVL_4) #define NUM_RCU_NODES (RCU_SUM - NR_CPUS) @@ -86,6 +91,14 @@ struct rcu_dynticks { /* remains even for nmi from irq handler. */ }; +/* RCU's kthread states for tracing. */ +#define RCU_KTHREAD_STOPPED 0 +#define RCU_KTHREAD_RUNNING 1 +#define RCU_KTHREAD_WAITING 2 +#define RCU_KTHREAD_OFFCPU 3 +#define RCU_KTHREAD_YIELDING 4 +#define RCU_KTHREAD_MAX 4 + /* * Definition for node within the RCU grace-period-detection hierarchy. */ @@ -104,10 +117,11 @@ struct rcu_node { /* an rcu_data structure, otherwise, each */ /* bit corresponds to a child rcu_node */ /* structure. */ - unsigned long expmask; /* Groups that have ->blocked_tasks[] */ + unsigned long expmask; /* Groups that have ->blkd_tasks */ /* elements that need to drain to allow the */ /* current expedited grace period to */ /* complete (only for TREE_PREEMPT_RCU). */ + unsigned long wakemask; /* CPUs whose kthread needs to be awakened. */ unsigned long qsmaskinit; /* Per-GP initial value for qsmask & expmask. */ unsigned long grpmask; /* Mask to apply to parent qsmask. */ @@ -117,11 +131,68 @@ struct rcu_node { u8 grpnum; /* CPU/group number for next level up. */ u8 level; /* root is at level 0. */ struct rcu_node *parent; - struct list_head blocked_tasks[4]; - /* Tasks blocked in RCU read-side critsect. */ - /* Grace period number (->gpnum) x blocked */ - /* by tasks on the (x & 0x1) element of the */ - /* blocked_tasks[] array. */ + struct list_head blkd_tasks; + /* Tasks blocked in RCU read-side critical */ + /* section. Tasks are placed at the head */ + /* of this list and age towards the tail. */ + struct list_head *gp_tasks; + /* Pointer to the first task blocking the */ + /* current grace period, or NULL if there */ + /* is no such task. */ + struct list_head *exp_tasks; + /* Pointer to the first task blocking the */ + /* current expedited grace period, or NULL */ + /* if there is no such task. If there */ + /* is no current expedited grace period, */ + /* then there can cannot be any such task. */ +#ifdef CONFIG_RCU_BOOST + struct list_head *boost_tasks; + /* Pointer to first task that needs to be */ + /* priority boosted, or NULL if no priority */ + /* boosting is needed for this rcu_node */ + /* structure. If there are no tasks */ + /* queued on this rcu_node structure that */ + /* are blocking the current grace period, */ + /* there can be no such task. */ + unsigned long boost_time; + /* When to start boosting (jiffies). */ + struct task_struct *boost_kthread_task; + /* kthread that takes care of priority */ + /* boosting for this rcu_node structure. */ + wait_queue_head_t boost_wq; + /* Wait queue on which to park the boost */ + /* kthread. */ + unsigned int boost_kthread_status; + /* State of boost_kthread_task for tracing. */ + 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 */ + /* structure, for example, awakening the */ + /* per-CPU kthreads as needed. */ + wait_queue_head_t node_wq; + /* Wait queue on which to park the per-node */ + /* kthread. */ + unsigned int node_kthread_status; + /* State of node_kthread_task for tracing. */ } ____cacheline_internodealigned_in_smp; /* @@ -170,7 +241,7 @@ struct rcu_data { bool passed_quiesc; /* User-mode/idle loop etc. */ bool qs_pending; /* Core waits for quiesc state. */ bool beenonline; /* CPU online at least once. */ - bool preemptable; /* Preemptable RCU? */ + bool preemptible; /* Preemptible RCU? */ struct rcu_node *mynode; /* This CPU's leaf of hierarchy */ unsigned long grpmask; /* Mask to apply to leaf qsmask. */ @@ -203,8 +274,8 @@ struct rcu_data { long qlen_last_fqs_check; /* qlen at last check for QS forcing */ unsigned long n_cbs_invoked; /* count of RCU cbs invoked. */ - unsigned long n_cbs_orphaned; /* RCU cbs sent to orphanage. */ - unsigned long n_cbs_adopted; /* RCU cbs adopted from orphanage. */ + unsigned long n_cbs_orphaned; /* RCU cbs orphaned by dying CPU */ + unsigned long n_cbs_adopted; /* RCU cbs adopted from dying CPU */ unsigned long n_force_qs_snap; /* did other CPU force QS recently? */ long blimit; /* Upper limit on a processed batch */ @@ -249,7 +320,6 @@ struct rcu_data { #endif /* #else #ifdef CONFIG_NO_HZ */ #define RCU_JIFFIES_TILL_FORCE_QS 3 /* for rsp->jiffies_force_qs */ -#ifdef CONFIG_RCU_CPU_STALL_DETECTOR #ifdef CONFIG_PROVE_RCU #define RCU_STALL_DELAY_DELTA (5 * HZ) @@ -267,13 +337,6 @@ struct rcu_data { /* scheduling clock irq */ /* before ratting on them. */ -#ifdef CONFIG_RCU_CPU_STALL_DETECTOR_RUNNABLE -#define RCU_CPU_STALL_SUPPRESS_INIT 0 -#else -#define RCU_CPU_STALL_SUPPRESS_INIT 1 -#endif - -#endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */ /* * RCU global state, including node hierarchy. This hierarchy is @@ -309,15 +372,7 @@ struct rcu_state { /* End of fields guarded by root rcu_node's lock. */ raw_spinlock_t onofflock; /* exclude on/offline and */ - /* starting new GP. Also */ - /* protects the following */ - /* orphan_cbs fields. */ - struct rcu_head *orphan_cbs_list; /* list of rcu_head structs */ - /* orphaned by all CPUs in */ - /* a given leaf rcu_node */ - /* going offline. */ - struct rcu_head **orphan_cbs_tail; /* And tail pointer. */ - long orphan_qlen; /* Number of orphaned cbs. */ + /* starting new GP. */ raw_spinlock_t fqslock; /* Only one task forcing */ /* quiescent states. */ unsigned long jiffies_force_qs; /* Time at which to invoke */ @@ -328,12 +383,12 @@ struct rcu_state { /* due to lock unavailable. */ unsigned long n_force_qs_ngp; /* Number of calls leaving */ /* due to no GP active. */ -#ifdef CONFIG_RCU_CPU_STALL_DETECTOR unsigned long gp_start; /* Time at which GP started, */ /* but in jiffies. */ unsigned long jiffies_stall; /* Time at which to check */ /* for CPU stalls. */ -#endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */ + unsigned long gp_max; /* Maximum GP duration in */ + /* jiffies. */ char *name; /* Name of structure. */ }; @@ -364,16 +419,14 @@ DECLARE_PER_CPU(struct rcu_data, rcu_preempt_data); static void rcu_bootup_announce(void); long rcu_batches_completed(void); static void rcu_preempt_note_context_switch(int cpu); -static int rcu_preempted_readers(struct rcu_node *rnp); +static int rcu_preempt_blocked_readers_cgp(struct rcu_node *rnp); #ifdef CONFIG_HOTPLUG_CPU static void rcu_report_unblock_qs_rnp(struct rcu_node *rnp, unsigned long flags); #endif /* #ifdef CONFIG_HOTPLUG_CPU */ -#ifdef CONFIG_RCU_CPU_STALL_DETECTOR static void rcu_print_detail_task_stall(struct rcu_state *rsp); static void rcu_print_task_stall(struct rcu_node *rnp); static void rcu_preempt_stall_reset(void); -#endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */ static void rcu_preempt_check_blocked_tasks(struct rcu_node *rnp); #ifdef CONFIG_HOTPLUG_CPU static int rcu_preempt_offline_tasks(struct rcu_state *rsp, @@ -390,8 +443,16 @@ static void rcu_report_exp_rnp(struct rcu_state *rsp, struct rcu_node *rnp); static int rcu_preempt_pending(int cpu); static int rcu_preempt_needs_cpu(int cpu); static void __cpuinit rcu_preempt_init_percpu_data(int cpu); -static void rcu_preempt_send_cbs_to_orphanage(void); +static void rcu_preempt_send_cbs_to_online(void); static void __init __rcu_init_preempt(void); static void rcu_needs_cpu_flush(void); +static void __init rcu_init_boost_waitqueue(struct rcu_node *rnp); +static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags); +static void rcu_boost_kthread_setaffinity(struct rcu_node *rnp, + cpumask_var_t cm); +static void rcu_preempt_boost_start_gp(struct rcu_node *rnp); +static int __cpuinit rcu_spawn_one_boost_kthread(struct rcu_state *rsp, + struct rcu_node *rnp, + int rnp_index); #endif /* #ifndef RCU_TREE_NONCORE */ |