#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"
#include <sched.h>
#include <time.h>
#include <pthread.h>
+#include <unistd.h>
#define YIELD_READ (1 << 0)
#define YIELD_WRITE (1 << 1)
+/* Updates without DEBUG_FULL_MB are much slower. Account this in the delay */
+#ifdef DEBUG_FULL_MB
+/* maximum sleep delay, in us */
+#define MAX_SLEEP 50
+#else
+#define MAX_SLEEP 30000
+#endif
+
extern unsigned int yield_active;
extern unsigned int __thread rand_yield;
{
if (yield_active & YIELD_READ)
if (rand_r(&rand_yield) & 0x1)
- sched_yield();
+ usleep(rand_r(&rand_yield) % MAX_SLEEP);
}
static inline void debug_yield_write(void)
{
if (yield_active & YIELD_WRITE)
if (rand_r(&rand_yield) & 0x1)
- sched_yield();
+ usleep(rand_r(&rand_yield) % MAX_SLEEP);
}
static inline void debug_yield_init(void)
}
#endif
+#ifdef DEBUG_FULL_MB
+static inline void read_barrier()
+{
+ smp_mb();
+}
+#else
+static inline void read_barrier()
+{
+ barrier();
+}
+#endif
+
/*
* The trick here is that RCU_GP_CTR_BIT must be a multiple of 8 so we can use a
* full 8-bits, 16-bits or 32-bits bitmask for the lower order bits.
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);
debug_yield_write();
return (v & RCU_GP_CTR_NEST_MASK) &&
- ((v ^ ACCESS_ONCE(urcu_gp_ctr)) & RCU_GP_CTR_BIT);
+ ((v ^ urcu_gp_ctr) & RCU_GP_CTR_BIT);
}
static inline void rcu_read_lock(void)
debug_yield_read();
tmp = urcu_active_readers;
debug_yield_read();
+ /* urcu_gp_ctr = RCU_GP_COUNT | (~RCU_GP_CTR_BIT or RCU_GP_CTR_BIT) */
if (likely(!(tmp & RCU_GP_CTR_NEST_MASK)))
urcu_active_readers = urcu_gp_ctr;
else
* Increment active readers count before accessing the pointer.
* See force_mb_all_threads().
*/
- barrier();
+ read_barrier();
debug_yield_read();
}
static inline void rcu_read_unlock(void)
{
debug_yield_read();
- barrier();
+ read_barrier();
debug_yield_read();
/*
* Finish using rcu before decrementing the pointer.