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Add barriers
[userspace-rcu.git]
/
urcu.h
diff --git
a/urcu.h
b/urcu.h
index c4a7992b4b7b166d527411d4ae5108cac174fc95..3eca5ea3c44ccc7135635229c41141d5050df1e2 100644
(file)
--- a/
urcu.h
+++ b/
urcu.h
@@
-31,6
+31,19
@@
#define rmb() asm volatile("lfence":::"memory")
#define wmb() asm volatile("sfence" ::: "memory")
#define rmb() asm volatile("lfence":::"memory")
#define wmb() asm volatile("sfence" ::: "memory")
+/* Assume SMP machine, given we don't have this information */
+#define CONFIG_SMP 1
+
+#ifdef CONFIG_SMP
+#define smp_mb() mb()
+#define smp_rmb() rmb()
+#define smp_wmb() wmb()
+#else
+#define smp_mb() barrier()
+#define smp_rmb() barrier()
+#define smp_wmb() barrier()
+#endif
+
static inline void atomic_inc(int *v)
{
asm volatile("lock; incl %0"
static inline void atomic_inc(int *v)
{
asm volatile("lock; incl %0"
@@
-117,6
+130,13
@@
static inline unsigned long __xchg(unsigned long x, volatile void *ptr,
#define SIGURCU SIGUSR1
#define SIGURCU SIGUSR1
+/*
+ * If a reader is really non-cooperative and refuses to commit its
+ * urcu_active_readers count to memory (there is no barrier in the reader
+ * per-se), kick it after a few loops waiting for it.
+ */
+#define KICK_READER_LOOPS 10000
+
#ifdef DEBUG_YIELD
#include <sched.h>
#include <time.h>
#ifdef DEBUG_YIELD
#include <sched.h>
#include <time.h>
@@
-173,7
+193,7
@@
static inline void debug_yield_init(void)
#ifdef DEBUG_FULL_MB
static inline void read_barrier()
{
#ifdef DEBUG_FULL_MB
static inline void read_barrier()
{
- mb();
+
smp_
mb();
}
#else
static inline void read_barrier()
}
#else
static inline void read_barrier()
@@
-206,13
+226,11
@@
static inline int rcu_old_gp_ongoing(long *value)
if (value == NULL)
return 0;
if (value == NULL)
return 0;
- debug_yield_write();
/*
* Make sure both tests below are done on the same version of *value
* to insure consistency.
*/
v = ACCESS_ONCE(*value);
/*
* Make sure both tests below are done on the same version of *value
* to insure consistency.
*/
v = ACCESS_ONCE(*value);
- debug_yield_write();
return (v & RCU_GP_CTR_NEST_MASK) &&
((v ^ urcu_gp_ctr) & RCU_GP_CTR_BIT);
}
return (v & RCU_GP_CTR_NEST_MASK) &&
((v ^ urcu_gp_ctr) & RCU_GP_CTR_BIT);
}
@@
-221,34
+239,29
@@
static inline void rcu_read_lock(void)
{
long tmp;
{
long tmp;
- debug_yield_read();
tmp = urcu_active_readers;
tmp = urcu_active_readers;
- debug_yield_read();
/* urcu_gp_ctr = RCU_GP_COUNT | (~RCU_GP_CTR_BIT or RCU_GP_CTR_BIT) */
/* urcu_gp_ctr = RCU_GP_COUNT | (~RCU_GP_CTR_BIT or RCU_GP_CTR_BIT) */
+ /* The data dependency "read urcu_gp_ctr, write urcu_active_readers",
+ * serializes those two memory operations. */
if (likely(!(tmp & RCU_GP_CTR_NEST_MASK)))
urcu_active_readers = urcu_gp_ctr;
else
urcu_active_readers = tmp + RCU_GP_COUNT;
if (likely(!(tmp & RCU_GP_CTR_NEST_MASK)))
urcu_active_readers = urcu_gp_ctr;
else
urcu_active_readers = tmp + RCU_GP_COUNT;
- debug_yield_read();
/*
* Increment active readers count before accessing the pointer.
* See force_mb_all_threads().
*/
read_barrier();
/*
* Increment active readers count before accessing the pointer.
* See force_mb_all_threads().
*/
read_barrier();
- debug_yield_read();
}
static inline void rcu_read_unlock(void)
{
}
static inline void rcu_read_unlock(void)
{
- debug_yield_read();
read_barrier();
read_barrier();
- debug_yield_read();
/*
* Finish using rcu before decrementing the pointer.
* See force_mb_all_threads().
*/
urcu_active_readers -= RCU_GP_COUNT;
/*
* Finish using rcu before decrementing the pointer.
* See force_mb_all_threads().
*/
urcu_active_readers -= RCU_GP_COUNT;
- debug_yield_read();
}
/**
}
/**
@@
-289,7
+302,6
@@
extern void synchronize_rcu(void);
#define urcu_publish_content(p, v) \
({ \
void *oldptr; \
#define urcu_publish_content(p, v) \
({ \
void *oldptr; \
- debug_yield_write(); \
oldptr = rcu_xchg_pointer(p, v); \
synchronize_rcu(); \
oldptr; \
oldptr = rcu_xchg_pointer(p, v); \
synchronize_rcu(); \
oldptr; \
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