* TO BE INCLUDED ONLY IN LGPL-COMPATIBLE CODE. See urcu.h for linking
* dynamically with the userspace rcu library.
*
- * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
+ * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
* Copyright (c) 2009 Paul E. McKenney, IBM Corporation.
*
* This library is free software; you can redistribute it and/or
extern "C" {
#endif
+/* Default is RCU_MEMBARRIER */
+#if !defined(RCU_MEMBARRIER) && !defined(RCU_MB) && !defined(RCU_SIGNAL)
+#define RCU_MEMBARRIER
+#endif
+
+#ifdef RCU_MEMBARRIER
+#include <unistd.h>
+#include <sys/syscall.h>
+
+/* If the headers do not support SYS_membarrier, statically use RCU_MB */
+#ifdef SYS_membarrier
+# define MEMBARRIER_EXPEDITED (1 << 0)
+# define MEMBARRIER_DELAYED (1 << 1)
+# define MEMBARRIER_QUERY (1 << 16)
+# define membarrier(...) syscall(SYS_membarrier, __VA_ARGS__)
+#else
+# undef RCU_MEMBARRIER
+# define RCU_MB
+#endif
+#endif
+
/*
* This code section can only be included in LGPL 2.1 compatible source code.
* See below for the function call wrappers which can be used in code meant to
/*
* The signal number used by the RCU library can be overridden with
* -DSIGRCU= when compiling the library.
+ * Provide backward compatibility for liburcu 0.3.x SIGURCU.
*/
+#ifdef SIGURCU
+#define SIGRCU SIGURCU
+#endif
+
#ifndef SIGRCU
#define SIGRCU SIGUSR1
#endif
#define YIELD_WRITE (1 << 1)
/*
- * Updates without RCU_MB are much slower. Account this in
- * the delay.
+ * Updates with RCU_SIGNAL are much slower. Account this in the delay.
*/
-#ifdef RCU_MB
+#ifdef RCU_SIGNAL
/* maximum sleep delay, in us */
-#define MAX_SLEEP 50
-#else
#define MAX_SLEEP 30000
+#else
+#define MAX_SLEEP 50
#endif
extern unsigned int yield_active;
}
#endif
+/*
+ * RCU memory barrier broadcast group. Currently, only broadcast to all process
+ * threads is supported (group 0).
+ *
+ * Slave barriers are only guaranteed to be ordered wrt master barriers.
+ *
+ * The pair ordering is detailed as (O: ordered, X: not ordered) :
+ * slave master
+ * slave X O
+ * master O O
+ */
+
+#define MB_GROUP_ALL 0
+#define RCU_MB_GROUP MB_GROUP_ALL
+
+#ifdef RCU_MEMBARRIER
+extern int has_sys_membarrier;
+
+static inline void smp_mb_slave(int group)
+{
+ if (likely(has_sys_membarrier))
+ cmm_barrier();
+ else
+ cmm_smp_mb();
+}
+#endif
+
#ifdef RCU_MB
-static inline void reader_barrier()
+static inline void smp_mb_slave(int group)
{
- smp_mb();
+ cmm_smp_mb();
}
-#else
-static inline void reader_barrier()
+#endif
+
+#ifdef RCU_SIGNAL
+static inline void smp_mb_slave(int group)
{
- barrier();
+ cmm_barrier();
}
#endif
*/
#define RCU_GP_COUNT (1UL << 0)
/* Use the amount of bits equal to half of the architecture long size */
-#define RCU_GP_CTR_PHASE (1UL << (sizeof(long) << 2))
+#define RCU_GP_CTR_PHASE (1UL << (sizeof(unsigned long) << 2))
#define RCU_GP_CTR_NEST_MASK (RCU_GP_CTR_PHASE - 1)
/*
* Using a int rather than a char to eliminate false register dependencies
* causing stalls on some architectures.
*/
-extern long rcu_gp_ctr;
+extern unsigned long rcu_gp_ctr;
struct rcu_reader {
/* Data used by both reader and synchronize_rcu() */
- long ctr;
+ unsigned long ctr;
char need_mb;
/* Data used for registry */
- struct list_head head __attribute__((aligned(CACHE_LINE_SIZE)));
+ struct cds_list_head node __attribute__((aligned(CAA_CACHE_LINE_SIZE)));
pthread_t tid;
};
}
}
-static inline int rcu_old_gp_ongoing(long *value)
+static inline int rcu_gp_ongoing(unsigned long *ctr)
{
- long v;
+ unsigned long v;
- if (value == NULL)
- return 0;
/*
* Make sure both tests below are done on the same version of *value
* to insure consistency.
*/
- v = LOAD_SHARED(*value);
+ v = CMM_LOAD_SHARED(*ctr);
return (v & RCU_GP_CTR_NEST_MASK) &&
((v ^ rcu_gp_ctr) & RCU_GP_CTR_PHASE);
}
static inline void _rcu_read_lock(void)
{
- long tmp;
+ unsigned long tmp;
+ cmm_barrier(); /* Ensure the compiler does not reorder us with mutex */
tmp = rcu_reader.ctr;
/*
* rcu_gp_ctr is
* RCU_GP_COUNT | (~RCU_GP_CTR_PHASE or RCU_GP_CTR_PHASE)
*/
if (likely(!(tmp & RCU_GP_CTR_NEST_MASK))) {
- _STORE_SHARED(rcu_reader.ctr, _LOAD_SHARED(rcu_gp_ctr));
+ _CMM_STORE_SHARED(rcu_reader.ctr, _CMM_LOAD_SHARED(rcu_gp_ctr));
/*
* Set active readers count for outermost nesting level before
- * accessing the pointer. See force_mb_all_readers().
+ * accessing the pointer. See smp_mb_master().
*/
- reader_barrier();
+ smp_mb_slave(RCU_MB_GROUP);
} else {
- _STORE_SHARED(rcu_reader.ctr, tmp + RCU_GP_COUNT);
+ _CMM_STORE_SHARED(rcu_reader.ctr, tmp + RCU_GP_COUNT);
}
}
static inline void _rcu_read_unlock(void)
{
- long tmp;
+ unsigned long tmp;
tmp = rcu_reader.ctr;
/*
* Finish using rcu before decrementing the pointer.
- * See force_mb_all_readers().
+ * See smp_mb_master().
*/
if (likely((tmp & RCU_GP_CTR_NEST_MASK) == RCU_GP_COUNT)) {
- reader_barrier();
- _STORE_SHARED(rcu_reader.ctr, rcu_reader.ctr - RCU_GP_COUNT);
+ smp_mb_slave(RCU_MB_GROUP);
+ _CMM_STORE_SHARED(rcu_reader.ctr, rcu_reader.ctr - RCU_GP_COUNT);
/* write rcu_reader.ctr before read futex */
- reader_barrier();
+ smp_mb_slave(RCU_MB_GROUP);
wake_up_gp();
} else {
- _STORE_SHARED(rcu_reader.ctr, rcu_reader.ctr - RCU_GP_COUNT);
+ _CMM_STORE_SHARED(rcu_reader.ctr, rcu_reader.ctr - RCU_GP_COUNT);
}
+ cmm_barrier(); /* Ensure the compiler does not reorder us with mutex */
}
-#ifdef __cplusplus
+#ifdef __cplusplus
}
#endif
projects / urcu.git / blobdiff