diff options
Diffstat (limited to 'kernel/rcutree.h')
| -rw-r--r-- | kernel/rcutree.h | 475 |
1 files changed, 0 insertions, 475 deletions
diff --git a/kernel/rcutree.h b/kernel/rcutree.h deleted file mode 100644 index fddff92d667..00000000000 --- a/kernel/rcutree.h +++ /dev/null @@ -1,475 +0,0 @@ -/* - * Read-Copy Update mechanism for mutual exclusion (tree-based version) - * Internal non-public definitions. - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation; either version 2 of the License, or - * (at your option) any later version. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public License - * along with this program; if not, write to the Free Software - * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. - * - * Copyright IBM Corporation, 2008 - * - * Author: Ingo Molnar <mingo@elte.hu> - * Paul E. McKenney <paulmck@linux.vnet.ibm.com> - */ - -#include <linux/cache.h> -#include <linux/spinlock.h> -#include <linux/threads.h> -#include <linux/cpumask.h> -#include <linux/seqlock.h> - -/* - * 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 did work well going from three levels to four. - * Of course, your mileage may vary. - */ -#define MAX_RCU_LVLS 4 -#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_2 -# define NUM_RCU_LVLS 2 -# define NUM_RCU_LVL_0 1 -# 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_3 -# define NUM_RCU_LVLS 3 -# define NUM_RCU_LVL_0 1 -# 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_4 -# define NUM_RCU_LVLS 4 -# define NUM_RCU_LVL_0 1 -# 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_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) - -/* - * Dynticks per-CPU state. - */ -struct rcu_dynticks { - long long dynticks_nesting; /* Track irq/process nesting level. */ - /* Process level is worth LLONG_MAX/2. */ - int dynticks_nmi_nesting; /* Track NMI nesting level. */ - atomic_t dynticks; /* Even value for 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_OFFCPU 3 -#define RCU_KTHREAD_YIELDING 4 -#define RCU_KTHREAD_MAX 4 - -/* - * Definition for node within the RCU grace-period-detection hierarchy. - */ -struct rcu_node { - raw_spinlock_t lock; /* Root rcu_node's lock protects some */ - /* rcu_state fields as well as following. */ - unsigned long gpnum; /* Current grace period for this node. */ - /* This will either be equal to or one */ - /* behind the root rcu_node's gpnum. */ - unsigned long completed; /* Last GP completed for this node. */ - /* This will either be equal to or one */ - /* behind the root rcu_node's gpnum. */ - unsigned long qsmask; /* CPUs or groups that need to switch in */ - /* order for current grace period to proceed.*/ - /* In leaf rcu_node, each bit corresponds to */ - /* an rcu_data structure, otherwise, each */ - /* bit corresponds to a child rcu_node */ - /* structure. */ - 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). */ - atomic_t wakemask; /* CPUs whose kthread needs to be awakened. */ - /* Since this has meaning only for leaf */ - /* rcu_node structures, 32 bits suffices. */ - unsigned long qsmaskinit; - /* Per-GP initial value for qsmask & expmask. */ - unsigned long grpmask; /* Mask to apply to parent qsmask. */ - /* Only one bit will be set in this mask. */ - int grplo; /* lowest-numbered CPU or group here. */ - int grphi; /* highest-numbered CPU or group here. */ - u8 grpnum; /* CPU/group number for next level up. */ - u8 level; /* root is at level 0. */ - struct rcu_node *parent; - 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. */ - 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. */ - unsigned int node_kthread_status; - /* State of node_kthread_task for tracing. */ -} ____cacheline_internodealigned_in_smp; - -/* - * Do a full breadth-first scan of the rcu_node structures for the - * specified rcu_state structure. - */ -#define rcu_for_each_node_breadth_first(rsp, rnp) \ - for ((rnp) = &(rsp)->node[0]; \ - (rnp) < &(rsp)->node[NUM_RCU_NODES]; (rnp)++) - -/* - * Do a breadth-first scan of the non-leaf rcu_node structures for the - * specified rcu_state structure. Note that if there is a singleton - * rcu_node tree with but one rcu_node structure, this loop is a no-op. - */ -#define rcu_for_each_nonleaf_node_breadth_first(rsp, rnp) \ - for ((rnp) = &(rsp)->node[0]; \ - (rnp) < (rsp)->level[NUM_RCU_LVLS - 1]; (rnp)++) - -/* - * Scan the leaves of the rcu_node hierarchy for the specified rcu_state - * structure. Note that if there is a singleton rcu_node tree with but - * one rcu_node structure, this loop -will- visit the rcu_node structure. - * It is still a leaf node, even if it is also the root node. - */ -#define rcu_for_each_leaf_node(rsp, rnp) \ - for ((rnp) = (rsp)->level[NUM_RCU_LVLS - 1]; \ - (rnp) < &(rsp)->node[NUM_RCU_NODES]; (rnp)++) - -/* Index values for nxttail array in struct rcu_data. */ -#define RCU_DONE_TAIL 0 /* Also RCU_WAIT head. */ -#define RCU_WAIT_TAIL 1 /* Also RCU_NEXT_READY head. */ -#define RCU_NEXT_READY_TAIL 2 /* Also RCU_NEXT head. */ -#define RCU_NEXT_TAIL 3 -#define RCU_NEXT_SIZE 4 - -/* Per-CPU data for read-copy update. */ -struct rcu_data { - /* 1) quiescent-state and grace-period handling : */ - unsigned long completed; /* Track rsp->completed gp number */ - /* in order to detect GP end. */ - unsigned long gpnum; /* Highest gp number that this CPU */ - /* is aware of having started. */ - unsigned long passed_quiesce_gpnum; - /* gpnum at time of quiescent state. */ - bool passed_quiesce; /* User-mode/idle loop etc. */ - bool qs_pending; /* Core waits for quiesc state. */ - bool beenonline; /* CPU online at least once. */ - bool preemptible; /* Preemptible RCU? */ - struct rcu_node *mynode; /* This CPU's leaf of hierarchy */ - unsigned long grpmask; /* Mask to apply to leaf qsmask. */ - - /* 2) batch handling */ - /* - * If nxtlist is not NULL, it is partitioned as follows. - * Any of the partitions might be empty, in which case the - * pointer to that partition will be equal to the pointer for - * the following partition. When the list is empty, all of - * the nxttail elements point to the ->nxtlist pointer itself, - * which in that case is NULL. - * - * [nxtlist, *nxttail[RCU_DONE_TAIL]): - * Entries that batch # <= ->completed - * The grace period for these entries has completed, and - * the other grace-period-completed entries may be moved - * here temporarily in rcu_process_callbacks(). - * [*nxttail[RCU_DONE_TAIL], *nxttail[RCU_WAIT_TAIL]): - * Entries that batch # <= ->completed - 1: waiting for current GP - * [*nxttail[RCU_WAIT_TAIL], *nxttail[RCU_NEXT_READY_TAIL]): - * Entries known to have arrived before current GP ended - * [*nxttail[RCU_NEXT_READY_TAIL], *nxttail[RCU_NEXT_TAIL]): - * Entries that might have arrived after current GP ended - * Note that the value of *nxttail[RCU_NEXT_TAIL] will - * always be NULL, as this is the end of the list. - */ - struct rcu_head *nxtlist; - struct rcu_head **nxttail[RCU_NEXT_SIZE]; - long qlen; /* # of queued callbacks */ - 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 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 */ - - /* 3) dynticks interface. */ - struct rcu_dynticks *dynticks; /* Shared per-CPU dynticks state. */ - int dynticks_snap; /* Per-GP tracking for dynticks. */ - - /* 4) reasons this CPU needed to be kicked by force_quiescent_state */ - unsigned long dynticks_fqs; /* Kicked due to dynticks idle. */ - unsigned long offline_fqs; /* Kicked due to being offline. */ - unsigned long resched_ipi; /* Sent a resched IPI. */ - - /* 5) __rcu_pending() statistics. */ - unsigned long n_rcu_pending; /* rcu_pending() calls since boot. */ - unsigned long n_rp_qs_pending; - unsigned long n_rp_report_qs; - unsigned long n_rp_cb_ready; - unsigned long n_rp_cpu_needs_gp; - unsigned long n_rp_gp_completed; - unsigned long n_rp_gp_started; - unsigned long n_rp_need_fqs; - unsigned long n_rp_need_nothing; - - int cpu; - struct rcu_state *rsp; -}; - -/* Values for fqs_state field in struct rcu_state. */ -#define RCU_GP_IDLE 0 /* No grace period in progress. */ -#define RCU_GP_INIT 1 /* Grace period being initialized. */ -#define RCU_SAVE_DYNTICK 2 /* Need to scan dyntick state. */ -#define RCU_FORCE_QS 3 /* Need to force quiescent state. */ -#define RCU_SIGNAL_INIT RCU_SAVE_DYNTICK - -#define RCU_JIFFIES_TILL_FORCE_QS 3 /* for rsp->jiffies_force_qs */ - -#ifdef CONFIG_PROVE_RCU -#define RCU_STALL_DELAY_DELTA (5 * HZ) -#else -#define RCU_STALL_DELAY_DELTA 0 -#endif - -#define RCU_SECONDS_TILL_STALL_CHECK (CONFIG_RCU_CPU_STALL_TIMEOUT * HZ + \ - RCU_STALL_DELAY_DELTA) - /* for rsp->jiffies_stall */ -#define RCU_SECONDS_TILL_STALL_RECHECK (3 * RCU_SECONDS_TILL_STALL_CHECK + 30) - /* for rsp->jiffies_stall */ -#define RCU_STALL_RAT_DELAY 2 /* Allow other CPUs time */ - /* to take at least one */ - /* scheduling clock irq */ - /* before ratting on them. */ - -#define rcu_wait(cond) \ -do { \ - for (;;) { \ - set_current_state(TASK_INTERRUPTIBLE); \ - if (cond) \ - break; \ - schedule(); \ - } \ - __set_current_state(TASK_RUNNING); \ -} while (0) - -/* - * RCU global state, including node hierarchy. This hierarchy is - * represented in "heap" form in a dense array. The root (first level) - * of the hierarchy is in ->node[0] (referenced by ->level[0]), the second - * level in ->node[1] through ->node[m] (->node[1] referenced by ->level[1]), - * and the third level in ->node[m+1] and following (->node[m+1] referenced - * by ->level[2]). The number of levels is determined by the number of - * CPUs and by CONFIG_RCU_FANOUT. Small systems will have a "hierarchy" - * consisting of a single rcu_node. - */ -struct rcu_state { - struct rcu_node node[NUM_RCU_NODES]; /* Hierarchy. */ - struct rcu_node *level[NUM_RCU_LVLS]; /* Hierarchy levels. */ - u32 levelcnt[MAX_RCU_LVLS + 1]; /* # nodes in each level. */ - u8 levelspread[NUM_RCU_LVLS]; /* kids/node in each level. */ - struct rcu_data __percpu *rda; /* pointer of percu rcu_data. */ - - /* The following fields are guarded by the root rcu_node's lock. */ - - u8 fqs_state ____cacheline_internodealigned_in_smp; - /* Force QS state. */ - u8 fqs_active; /* force_quiescent_state() */ - /* is running. */ - u8 fqs_need_gp; /* A CPU was prevented from */ - /* starting a new grace */ - /* period because */ - /* force_quiescent_state() */ - /* was running. */ - u8 boost; /* Subject to priority boost. */ - unsigned long gpnum; /* Current gp number. */ - unsigned long completed; /* # of last completed gp. */ - - /* End of fields guarded by root rcu_node's lock. */ - - raw_spinlock_t onofflock; /* exclude on/offline and */ - /* starting new GP. */ - raw_spinlock_t fqslock; /* Only one task forcing */ - /* quiescent states. */ - unsigned long jiffies_force_qs; /* Time at which to invoke */ - /* force_quiescent_state(). */ - unsigned long n_force_qs; /* Number of calls to */ - /* force_quiescent_state(). */ - unsigned long n_force_qs_lh; /* ~Number of calls leaving */ - /* due to lock unavailable. */ - unsigned long n_force_qs_ngp; /* Number of calls leaving */ - /* due to no GP active. */ - unsigned long gp_start; /* Time at which GP started, */ - /* but in jiffies. */ - unsigned long jiffies_stall; /* Time at which to check */ - /* for CPU stalls. */ - unsigned long gp_max; /* Maximum GP duration in */ - /* jiffies. */ - char *name; /* Name of structure. */ -}; - -/* Return values for rcu_preempt_offline_tasks(). */ - -#define RCU_OFL_TASKS_NORM_GP 0x1 /* Tasks blocking normal */ - /* GP were moved to root. */ -#define RCU_OFL_TASKS_EXP_GP 0x2 /* Tasks blocking expedited */ - /* GP were moved to root. */ - -/* - * RCU implementation internal declarations: - */ -extern struct rcu_state rcu_sched_state; -DECLARE_PER_CPU(struct rcu_data, rcu_sched_data); - -extern struct rcu_state rcu_bh_state; -DECLARE_PER_CPU(struct rcu_data, rcu_bh_data); - -#ifdef CONFIG_TREE_PREEMPT_RCU -extern struct rcu_state rcu_preempt_state; -DECLARE_PER_CPU(struct rcu_data, rcu_preempt_data); -#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */ - -#ifdef CONFIG_RCU_BOOST -DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_status); -DECLARE_PER_CPU(int, rcu_cpu_kthread_cpu); -DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_loops); -DECLARE_PER_CPU(char, rcu_cpu_has_work); -#endif /* #ifdef CONFIG_RCU_BOOST */ - -#ifndef RCU_TREE_NONCORE - -/* Forward declarations for rcutree_plugin.h */ -static void rcu_bootup_announce(void); -long rcu_batches_completed(void); -static void rcu_preempt_note_context_switch(int cpu); -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); -static void rcu_stop_cpu_kthread(int cpu); -#endif /* #ifdef CONFIG_HOTPLUG_CPU */ -static void rcu_print_detail_task_stall(struct rcu_state *rsp); -static int rcu_print_task_stall(struct rcu_node *rnp); -static void rcu_preempt_stall_reset(void); -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, - struct rcu_node *rnp, - struct rcu_data *rdp); -static void rcu_preempt_offline_cpu(int cpu); -#endif /* #ifdef CONFIG_HOTPLUG_CPU */ -static void rcu_preempt_check_callbacks(int cpu); -static void rcu_preempt_process_callbacks(void); -void call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu)); -#if defined(CONFIG_HOTPLUG_CPU) || defined(CONFIG_TREE_PREEMPT_RCU) -static void rcu_report_exp_rnp(struct rcu_state *rsp, struct rcu_node *rnp, - bool wake); -#endif /* #if defined(CONFIG_HOTPLUG_CPU) || defined(CONFIG_TREE_PREEMPT_RCU) */ -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_online(void); -static void __init __rcu_init_preempt(void); -static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags); -static void rcu_preempt_boost_start_gp(struct rcu_node *rnp); -static void invoke_rcu_callbacks_kthread(void); -static bool rcu_is_callbacks_kthread(void); -#ifdef CONFIG_RCU_BOOST -static void rcu_preempt_do_callbacks(void); -static void rcu_boost_kthread_setaffinity(struct rcu_node *rnp, - cpumask_var_t cm); -static int __cpuinit rcu_spawn_one_boost_kthread(struct rcu_state *rsp, - struct rcu_node *rnp, - int rnp_index); -static void invoke_rcu_node_kthread(struct rcu_node *rnp); -static void rcu_yield(void (*f)(unsigned long), unsigned long arg); -#endif /* #ifdef CONFIG_RCU_BOOST */ -static void rcu_cpu_kthread_setrt(int cpu, int to_rt); -static void __cpuinit rcu_prepare_kthreads(int cpu); -static void rcu_prepare_for_idle_init(int cpu); -static void rcu_cleanup_after_idle(int cpu); -static void rcu_prepare_for_idle(int cpu); - -#endif /* #ifndef RCU_TREE_NONCORE */ |