diff options
Diffstat (limited to 'kernel/rcu/rcu.h')
| -rw-r--r-- | kernel/rcu/rcu.h | 430 |
1 files changed, 428 insertions, 2 deletions
diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h index 0d6ff3e471be..808b8c85f626 100644 --- a/kernel/rcu/rcu.h +++ b/kernel/rcu/rcu.h @@ -56,6 +56,83 @@ #define DYNTICK_TASK_EXIT_IDLE (DYNTICK_TASK_NEST_VALUE + \ DYNTICK_TASK_FLAG) + +/* + * Grace-period counter management. + */ + +#define RCU_SEQ_CTR_SHIFT 2 +#define RCU_SEQ_STATE_MASK ((1 << RCU_SEQ_CTR_SHIFT) - 1) + +/* + * Return the counter portion of a sequence number previously returned + * by rcu_seq_snap() or rcu_seq_current(). + */ +static inline unsigned long rcu_seq_ctr(unsigned long s) +{ + return s >> RCU_SEQ_CTR_SHIFT; +} + +/* + * Return the state portion of a sequence number previously returned + * by rcu_seq_snap() or rcu_seq_current(). + */ +static inline int rcu_seq_state(unsigned long s) +{ + return s & RCU_SEQ_STATE_MASK; +} + +/* + * Set the state portion of the pointed-to sequence number. + * The caller is responsible for preventing conflicting updates. + */ +static inline void rcu_seq_set_state(unsigned long *sp, int newstate) +{ + WARN_ON_ONCE(newstate & ~RCU_SEQ_STATE_MASK); + WRITE_ONCE(*sp, (*sp & ~RCU_SEQ_STATE_MASK) + newstate); +} + +/* Adjust sequence number for start of update-side operation. */ +static inline void rcu_seq_start(unsigned long *sp) +{ + WRITE_ONCE(*sp, *sp + 1); + smp_mb(); /* Ensure update-side operation after counter increment. */ + WARN_ON_ONCE(rcu_seq_state(*sp) != 1); +} + +/* Adjust sequence number for end of update-side operation. */ +static inline void rcu_seq_end(unsigned long *sp) +{ + smp_mb(); /* Ensure update-side operation before counter increment. */ + WARN_ON_ONCE(!rcu_seq_state(*sp)); + WRITE_ONCE(*sp, (*sp | RCU_SEQ_STATE_MASK) + 1); +} + +/* Take a snapshot of the update side's sequence number. */ +static inline unsigned long rcu_seq_snap(unsigned long *sp) +{ + unsigned long s; + + s = (READ_ONCE(*sp) + 2 * RCU_SEQ_STATE_MASK + 1) & ~RCU_SEQ_STATE_MASK; + smp_mb(); /* Above access must not bleed into critical section. */ + return s; +} + +/* Return the current value the update side's sequence number, no ordering. */ +static inline unsigned long rcu_seq_current(unsigned long *sp) +{ + return READ_ONCE(*sp); +} + +/* + * Given a snapshot from rcu_seq_snap(), determine whether or not a + * full update-side operation has occurred. + */ +static inline bool rcu_seq_done(unsigned long *sp, unsigned long s) +{ + return ULONG_CMP_GE(READ_ONCE(*sp), s); +} + /* * debug_rcu_head_queue()/debug_rcu_head_unqueue() are used internally * by call_rcu() and rcu callback execution, and are therefore not part of the @@ -109,12 +186,12 @@ static inline bool __rcu_reclaim(const char *rn, struct rcu_head *head) rcu_lock_acquire(&rcu_callback_map); if (__is_kfree_rcu_offset(offset)) { - RCU_TRACE(trace_rcu_invoke_kfree_callback(rn, head, offset)); + RCU_TRACE(trace_rcu_invoke_kfree_callback(rn, head, offset);) kfree((void *)head - offset); rcu_lock_release(&rcu_callback_map); return true; } else { - RCU_TRACE(trace_rcu_invoke_callback(rn, head)); + RCU_TRACE(trace_rcu_invoke_callback(rn, head);) head->func(head); rcu_lock_release(&rcu_callback_map); return false; @@ -135,6 +212,18 @@ int rcu_jiffies_till_stall_check(void); */ #define TPS(x) tracepoint_string(x) +/* + * Dump the ftrace buffer, but only one time per callsite per boot. + */ +#define rcu_ftrace_dump(oops_dump_mode) \ +do { \ + static atomic_t ___rfd_beenhere = ATOMIC_INIT(0); \ + \ + if (!atomic_read(&___rfd_beenhere) && \ + !atomic_xchg(&___rfd_beenhere, 1)) \ + ftrace_dump(oops_dump_mode); \ +} while (0) + void rcu_early_boot_tests(void); void rcu_test_sync_prims(void); @@ -144,4 +233,341 @@ void rcu_test_sync_prims(void); */ extern void resched_cpu(int cpu); +#if defined(SRCU) || !defined(TINY_RCU) + +#include <linux/rcu_node_tree.h> + +extern int rcu_num_lvls; +extern int num_rcu_lvl[]; +extern int rcu_num_nodes; +static bool rcu_fanout_exact; +static int rcu_fanout_leaf; + +/* + * Compute the per-level fanout, either using the exact fanout specified + * or balancing the tree, depending on the rcu_fanout_exact boot parameter. + */ +static inline void rcu_init_levelspread(int *levelspread, const int *levelcnt) +{ + int i; + + if (rcu_fanout_exact) { + levelspread[rcu_num_lvls - 1] = rcu_fanout_leaf; + for (i = rcu_num_lvls - 2; i >= 0; i--) + levelspread[i] = RCU_FANOUT; + } else { + int ccur; + int cprv; + + cprv = nr_cpu_ids; + for (i = rcu_num_lvls - 1; i >= 0; i--) { + ccur = levelcnt[i]; + levelspread[i] = (cprv + ccur - 1) / ccur; + cprv = ccur; + } + } +} + +/* + * 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[rcu_num_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[rcu_num_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[rcu_num_lvls - 1]; \ + (rnp) < &(rsp)->node[rcu_num_nodes]; (rnp)++) + +/* + * Iterate over all possible CPUs in a leaf RCU node. + */ +#define for_each_leaf_node_possible_cpu(rnp, cpu) \ + for ((cpu) = cpumask_next(rnp->grplo - 1, cpu_possible_mask); \ + cpu <= rnp->grphi; \ + cpu = cpumask_next((cpu), cpu_possible_mask)) + +/* + * Wrappers for the rcu_node::lock acquire and release. + * + * Because the rcu_nodes form a tree, the tree traversal locking will observe + * different lock values, this in turn means that an UNLOCK of one level + * followed by a LOCK of another level does not imply a full memory barrier; + * and most importantly transitivity is lost. + * + * In order to restore full ordering between tree levels, augment the regular + * lock acquire functions with smp_mb__after_unlock_lock(). + * + * As ->lock of struct rcu_node is a __private field, therefore one should use + * these wrappers rather than directly call raw_spin_{lock,unlock}* on ->lock. + */ +#define raw_spin_lock_rcu_node(p) \ +do { \ + raw_spin_lock(&ACCESS_PRIVATE(p, lock)); \ + smp_mb__after_unlock_lock(); \ +} while (0) + +#define raw_spin_unlock_rcu_node(p) raw_spin_unlock(&ACCESS_PRIVATE(p, lock)) + +#define raw_spin_lock_irq_rcu_node(p) \ +do { \ + raw_spin_lock_irq(&ACCESS_PRIVATE(p, lock)); \ + smp_mb__after_unlock_lock(); \ +} while (0) + +#define raw_spin_unlock_irq_rcu_node(p) \ + raw_spin_unlock_irq(&ACCESS_PRIVATE(p, lock)) + +#define raw_spin_lock_irqsave_rcu_node(p, flags) \ +do { \ + raw_spin_lock_irqsave(&ACCESS_PRIVATE(p, lock), flags); \ + smp_mb__after_unlock_lock(); \ +} while (0) + +#define raw_spin_unlock_irqrestore_rcu_node(p, flags) \ + raw_spin_unlock_irqrestore(&ACCESS_PRIVATE(p, lock), flags) \ + +#define raw_spin_trylock_rcu_node(p) \ +({ \ + bool ___locked = raw_spin_trylock(&ACCESS_PRIVATE(p, lock)); \ + \ + if (___locked) \ + smp_mb__after_unlock_lock(); \ + ___locked; \ +}) + +#endif /* #if defined(SRCU) || !defined(TINY_RCU) */ + +#ifdef CONFIG_TINY_RCU +/* Tiny RCU doesn't expedite, as its purpose in life is instead to be tiny. */ +static inline bool rcu_gp_is_normal(void) /* Internal RCU use. */ +{ + return true; +} +static inline bool rcu_gp_is_expedited(void) /* Internal RCU use. */ +{ + return false; +} + +static inline void rcu_expedite_gp(void) +{ +} + +static inline void rcu_unexpedite_gp(void) +{ +} +#else /* #ifdef CONFIG_TINY_RCU */ +bool rcu_gp_is_normal(void); /* Internal RCU use. */ +bool rcu_gp_is_expedited(void); /* Internal RCU use. */ +void rcu_expedite_gp(void); +void rcu_unexpedite_gp(void); +void rcupdate_announce_bootup_oddness(void); +#endif /* #else #ifdef CONFIG_TINY_RCU */ + +#define RCU_SCHEDULER_INACTIVE 0 +#define RCU_SCHEDULER_INIT 1 +#define RCU_SCHEDULER_RUNNING 2 + +#ifdef CONFIG_TINY_RCU +static inline void rcu_request_urgent_qs_task(struct task_struct *t) { } +#else /* #ifdef CONFIG_TINY_RCU */ +void rcu_request_urgent_qs_task(struct task_struct *t); +#endif /* #else #ifdef CONFIG_TINY_RCU */ + +enum rcutorture_type { + RCU_FLAVOR, + RCU_BH_FLAVOR, + RCU_SCHED_FLAVOR, + RCU_TASKS_FLAVOR, + SRCU_FLAVOR, + INVALID_RCU_FLAVOR +}; + +#if defined(CONFIG_TREE_RCU) || defined(CONFIG_PREEMPT_RCU) +void rcutorture_get_gp_data(enum rcutorture_type test_type, int *flags, + unsigned long *gpnum, unsigned long *completed); +void rcutorture_record_test_transition(void); +void rcutorture_record_progress(unsigned long vernum); +void do_trace_rcu_torture_read(const char *rcutorturename, + struct rcu_head *rhp, + unsigned long secs, + unsigned long c_old, + unsigned long c); +#else +static inline void rcutorture_get_gp_data(enum rcutorture_type test_type, + int *flags, + unsigned long *gpnum, + unsigned long *completed) +{ + *flags = 0; + *gpnum = 0; + *completed = 0; +} +static inline void rcutorture_record_test_transition(void) +{ +} +static inline void rcutorture_record_progress(unsigned long vernum) +{ +} +#ifdef CONFIG_RCU_TRACE +void do_trace_rcu_torture_read(const char *rcutorturename, + struct rcu_head *rhp, + unsigned long secs, + unsigned long c_old, + unsigned long c); +#else +#define do_trace_rcu_torture_read(rcutorturename, rhp, secs, c_old, c) \ + do { } while (0) +#endif +#endif + +#ifdef CONFIG_TINY_SRCU + +static inline void srcutorture_get_gp_data(enum rcutorture_type test_type, + struct srcu_struct *sp, int *flags, + unsigned long *gpnum, + unsigned long *completed) +{ + if (test_type != SRCU_FLAVOR) + return; + *flags = 0; + *completed = sp->srcu_idx; + *gpnum = *completed; +} + +#elif defined(CONFIG_TREE_SRCU) + +void srcutorture_get_gp_data(enum rcutorture_type test_type, + struct srcu_struct *sp, int *flags, + unsigned long *gpnum, unsigned long *completed); + +#endif + +#ifdef CONFIG_TINY_RCU + +/* + * Return the number of grace periods started. + */ +static inline unsigned long rcu_batches_started(void) +{ + return 0; +} + +/* + * Return the number of bottom-half grace periods started. + */ +static inline unsigned long rcu_batches_started_bh(void) +{ + return 0; +} + +/* + * Return the number of sched grace periods started. + */ +static inline unsigned long rcu_batches_started_sched(void) +{ + return 0; +} + +/* + * Return the number of grace periods completed. + */ +static inline unsigned long rcu_batches_completed(void) +{ + return 0; +} + +/* + * Return the number of bottom-half grace periods completed. + */ +static inline unsigned long rcu_batches_completed_bh(void) +{ + return 0; +} + +/* + * Return the number of sched grace periods completed. + */ +static inline unsigned long rcu_batches_completed_sched(void) +{ + return 0; +} + +/* + * Return the number of expedited grace periods completed. + */ +static inline unsigned long rcu_exp_batches_completed(void) +{ + return 0; +} + +/* + * Return the number of expedited sched grace periods completed. + */ +static inline unsigned long rcu_exp_batches_completed_sched(void) +{ + return 0; +} + +static inline unsigned long srcu_batches_completed(struct srcu_struct *sp) +{ + return 0; +} + +static inline void rcu_force_quiescent_state(void) +{ +} + +static inline void rcu_bh_force_quiescent_state(void) +{ +} + +static inline void rcu_sched_force_quiescent_state(void) +{ +} + +static inline void show_rcu_gp_kthreads(void) +{ +} + +#else /* #ifdef CONFIG_TINY_RCU */ +extern unsigned long rcutorture_testseq; +extern unsigned long rcutorture_vernum; +unsigned long rcu_batches_started(void); +unsigned long rcu_batches_started_bh(void); +unsigned long rcu_batches_started_sched(void); +unsigned long rcu_batches_completed(void); +unsigned long rcu_batches_completed_bh(void); +unsigned long rcu_batches_completed_sched(void); +unsigned long rcu_exp_batches_completed(void); +unsigned long rcu_exp_batches_completed_sched(void); +unsigned long srcu_batches_completed(struct srcu_struct *sp); +void show_rcu_gp_kthreads(void); +void rcu_force_quiescent_state(void); +void rcu_bh_force_quiescent_state(void); +void rcu_sched_force_quiescent_state(void); +#endif /* #else #ifdef CONFIG_TINY_RCU */ + +#ifdef CONFIG_RCU_NOCB_CPU +bool rcu_is_nocb_cpu(int cpu); +#else +static inline bool rcu_is_nocb_cpu(int cpu) { return false; } +#endif + #endif /* __LINUX_RCU_H */ |