482 lines
14 KiB
C
482 lines
14 KiB
C
/*
|
|
* Read-Copy Update definitions shared among RCU implementations.
|
|
*
|
|
* 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, you can access it online at
|
|
* http://www.gnu.org/licenses/gpl-2.0.html.
|
|
*
|
|
* Copyright IBM Corporation, 2011
|
|
*
|
|
* Author: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
|
|
*/
|
|
|
|
#ifndef __LINUX_RCU_H
|
|
#define __LINUX_RCU_H
|
|
|
|
#include <trace/events/rcu.h>
|
|
#ifdef CONFIG_RCU_TRACE
|
|
#define RCU_TRACE(stmt) stmt
|
|
#else /* #ifdef CONFIG_RCU_TRACE */
|
|
#define RCU_TRACE(stmt)
|
|
#endif /* #else #ifdef CONFIG_RCU_TRACE */
|
|
|
|
/* Offset to allow for unmatched rcu_irq_{enter,exit}(). */
|
|
#define DYNTICK_IRQ_NONIDLE ((LONG_MAX / 2) + 1)
|
|
|
|
|
|
/*
|
|
* 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
|
|
* RCU API. Leaving in rcupdate.h because they are used by all RCU flavors.
|
|
*/
|
|
|
|
#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
|
|
# define STATE_RCU_HEAD_READY 0
|
|
# define STATE_RCU_HEAD_QUEUED 1
|
|
|
|
extern struct debug_obj_descr rcuhead_debug_descr;
|
|
|
|
static inline int debug_rcu_head_queue(struct rcu_head *head)
|
|
{
|
|
int r1;
|
|
|
|
r1 = debug_object_activate(head, &rcuhead_debug_descr);
|
|
debug_object_active_state(head, &rcuhead_debug_descr,
|
|
STATE_RCU_HEAD_READY,
|
|
STATE_RCU_HEAD_QUEUED);
|
|
return r1;
|
|
}
|
|
|
|
static inline void debug_rcu_head_unqueue(struct rcu_head *head)
|
|
{
|
|
debug_object_active_state(head, &rcuhead_debug_descr,
|
|
STATE_RCU_HEAD_QUEUED,
|
|
STATE_RCU_HEAD_READY);
|
|
debug_object_deactivate(head, &rcuhead_debug_descr);
|
|
}
|
|
#else /* !CONFIG_DEBUG_OBJECTS_RCU_HEAD */
|
|
static inline int debug_rcu_head_queue(struct rcu_head *head)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
static inline void debug_rcu_head_unqueue(struct rcu_head *head)
|
|
{
|
|
}
|
|
#endif /* #else !CONFIG_DEBUG_OBJECTS_RCU_HEAD */
|
|
|
|
void kfree(const void *);
|
|
|
|
/*
|
|
* Reclaim the specified callback, either by invoking it (non-lazy case)
|
|
* or freeing it directly (lazy case). Return true if lazy, false otherwise.
|
|
*/
|
|
static inline bool __rcu_reclaim(const char *rn, struct rcu_head *head)
|
|
{
|
|
unsigned long offset = (unsigned long)head->func;
|
|
|
|
rcu_lock_acquire(&rcu_callback_map);
|
|
if (__is_kfree_rcu_offset(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);)
|
|
head->func(head);
|
|
rcu_lock_release(&rcu_callback_map);
|
|
return false;
|
|
}
|
|
}
|
|
|
|
#ifdef CONFIG_RCU_STALL_COMMON
|
|
|
|
extern int rcu_cpu_stall_suppress;
|
|
int rcu_jiffies_till_stall_check(void);
|
|
|
|
#define rcu_ftrace_dump_stall_suppress() \
|
|
do { \
|
|
if (!rcu_cpu_stall_suppress) \
|
|
rcu_cpu_stall_suppress = 3; \
|
|
} while (0)
|
|
|
|
#define rcu_ftrace_dump_stall_unsuppress() \
|
|
do { \
|
|
if (rcu_cpu_stall_suppress == 3) \
|
|
rcu_cpu_stall_suppress = 0; \
|
|
} while (0)
|
|
|
|
#else /* #endif #ifdef CONFIG_RCU_STALL_COMMON */
|
|
#define rcu_ftrace_dump_stall_suppress()
|
|
#define rcu_ftrace_dump_stall_unsuppress()
|
|
#endif /* #ifdef CONFIG_RCU_STALL_COMMON */
|
|
|
|
/*
|
|
* Strings used in tracepoints need to be exported via the
|
|
* tracing system such that tools like perf and trace-cmd can
|
|
* translate the string address pointers to actual text.
|
|
*/
|
|
#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)) { \
|
|
tracing_off(); \
|
|
rcu_ftrace_dump_stall_suppress(); \
|
|
ftrace_dump(oops_dump_mode); \
|
|
rcu_ftrace_dump_stall_unsuppress(); \
|
|
} \
|
|
} while (0)
|
|
|
|
void rcu_early_boot_tests(void);
|
|
void rcu_test_sync_prims(void);
|
|
|
|
/*
|
|
* This function really isn't for public consumption, but RCU is special in
|
|
* that context switches can allow the state machine to make progress.
|
|
*/
|
|
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) { return true; }
|
|
static inline bool rcu_gp_is_expedited(void) { 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
|
|
static inline unsigned long rcu_batches_started(void) { return 0; }
|
|
static inline unsigned long rcu_batches_started_bh(void) { return 0; }
|
|
static inline unsigned long rcu_batches_started_sched(void) { return 0; }
|
|
static inline unsigned long rcu_batches_completed(void) { return 0; }
|
|
static inline unsigned long rcu_batches_completed_bh(void) { return 0; }
|
|
static inline unsigned long rcu_batches_completed_sched(void) { return 0; }
|
|
static inline unsigned long rcu_exp_batches_completed(void) { return 0; }
|
|
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 */
|