diff options
Diffstat (limited to 'include/linux/rcupdate.h')
| -rw-r--r-- | include/linux/rcupdate.h | 72 |
1 files changed, 71 insertions, 1 deletions
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 00a7fd61b3c6..5a75d19aa661 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -44,6 +44,7 @@ #include <linux/debugobjects.h> #include <linux/bug.h> #include <linux/compiler.h> +#include <linux/percpu.h> #include <asm/barrier.h> extern int rcu_expedited; /* for sysctl */ @@ -51,7 +52,17 @@ extern int rcu_expedited; /* for sysctl */ extern int rcutorture_runnable; /* for sysctl */ #endif /* #ifdef CONFIG_RCU_TORTURE_TEST */ +enum rcutorture_type { + RCU_FLAVOR, + RCU_BH_FLAVOR, + RCU_SCHED_FLAVOR, + SRCU_FLAVOR, + INVALID_RCU_FLAVOR +}; + #if defined(CONFIG_TREE_RCU) || defined(CONFIG_TREE_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, @@ -60,6 +71,15 @@ void do_trace_rcu_torture_read(const char *rcutorturename, 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) { } @@ -228,6 +248,18 @@ void rcu_idle_exit(void); void rcu_irq_enter(void); void rcu_irq_exit(void); +#ifdef CONFIG_RCU_STALL_COMMON +void rcu_sysrq_start(void); +void rcu_sysrq_end(void); +#else /* #ifdef CONFIG_RCU_STALL_COMMON */ +static inline void rcu_sysrq_start(void) +{ +} +static inline void rcu_sysrq_end(void) +{ +} +#endif /* #else #ifdef CONFIG_RCU_STALL_COMMON */ + #ifdef CONFIG_RCU_USER_QS void rcu_user_enter(void); void rcu_user_exit(void); @@ -268,6 +300,41 @@ bool __rcu_is_watching(void); #endif /* #if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE) || defined(CONFIG_SMP) */ /* + * Hooks for cond_resched() and friends to avoid RCU CPU stall warnings. + */ + +#define RCU_COND_RESCHED_LIM 256 /* ms vs. 100s of ms. */ +DECLARE_PER_CPU(int, rcu_cond_resched_count); +void rcu_resched(void); + +/* + * Is it time to report RCU quiescent states? + * + * Note unsynchronized access to rcu_cond_resched_count. Yes, we might + * increment some random CPU's count, and possibly also load the result from + * yet another CPU's count. We might even clobber some other CPU's attempt + * to zero its counter. This is all OK because the goal is not precision, + * but rather reasonable amortization of rcu_note_context_switch() overhead + * and extremely high probability of avoiding RCU CPU stall warnings. + * Note that this function has to be preempted in just the wrong place, + * many thousands of times in a row, for anything bad to happen. + */ +static inline bool rcu_should_resched(void) +{ + return raw_cpu_inc_return(rcu_cond_resched_count) >= + RCU_COND_RESCHED_LIM; +} + +/* + * Report quiscent states to RCU if it is time to do so. + */ +static inline void rcu_cond_resched(void) +{ + if (unlikely(rcu_should_resched())) + rcu_resched(); +} + +/* * Infrastructure to implement the synchronize_() primitives in * TREE_RCU and rcu_barrier_() primitives in TINY_RCU. */ @@ -328,7 +395,7 @@ extern struct lockdep_map rcu_lock_map; extern struct lockdep_map rcu_bh_lock_map; extern struct lockdep_map rcu_sched_lock_map; extern struct lockdep_map rcu_callback_map; -extern int debug_lockdep_rcu_enabled(void); +int debug_lockdep_rcu_enabled(void); /** * rcu_read_lock_held() - might we be in RCU read-side critical section? @@ -949,6 +1016,9 @@ static inline notrace void rcu_read_unlock_sched_notrace(void) * pointers, but you must use rcu_assign_pointer() to initialize the * external-to-structure pointer -after- you have completely initialized * the reader-accessible portions of the linked structure. + * + * Note that unlike rcu_assign_pointer(), RCU_INIT_POINTER() provides no + * ordering guarantees for either the CPU or the compiler. */ #define RCU_INIT_POINTER(p, v) \ do { \ |