+++ /dev/null
-#ifndef _URCU_STATIC_H
-#define _URCU_STATIC_H
-
-/*
- * urcu-static.h
- *
- * Userspace RCU header.
- *
- * 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@efficios.com>
- * Copyright (c) 2009 Paul E. McKenney, IBM Corporation.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2.1 of the License, or (at your option) any later version.
- *
- * This library 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
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
- *
- * IBM's contributions to this file may be relicensed under LGPLv2 or later.
- */
-
-#include <stdlib.h>
-#include <pthread.h>
-#include <syscall.h>
-#include <unistd.h>
-
-#include <urcu/compiler.h>
-#include <urcu/arch.h>
-#include <urcu/system.h>
-#include <urcu/uatomic_arch.h>
-#include <urcu/list.h>
-#include <urcu/urcu-futex.h>
-
-#ifdef __cplusplus
-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
- * be only linked with the Userspace RCU library. This comes with a small
- * performance degradation on the read-side due to the added function calls.
- * This is required to permit relinking with newer versions of the library.
- */
-
-/*
- * 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
-
-/*
- * If a reader is really non-cooperative and refuses to commit its
- * rcu_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
-
-/*
- * Active attempts to check for reader Q.S. before calling futex().
- */
-#define RCU_QS_ACTIVE_ATTEMPTS 100
-
-#ifdef DEBUG_RCU
-#define rcu_assert(args...) assert(args)
-#else
-#define rcu_assert(args...)
-#endif
-
-#ifdef DEBUG_YIELD
-#include <sched.h>
-#include <time.h>
-#include <pthread.h>
-#include <unistd.h>
-
-#define YIELD_READ (1 << 0)
-#define YIELD_WRITE (1 << 1)
-
-/*
- * Updates with RCU_SIGNAL are much slower. Account this in the delay.
- */
-#ifdef RCU_SIGNAL
-/* maximum sleep delay, in us */
-#define MAX_SLEEP 30000
-#else
-#define MAX_SLEEP 50
-#endif
-
-extern unsigned int yield_active;
-extern unsigned int __thread rand_yield;
-
-static inline void debug_yield_read(void)
-{
- if (yield_active & YIELD_READ)
- if (rand_r(&rand_yield) & 0x1)
- 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)
- usleep(rand_r(&rand_yield) % MAX_SLEEP);
-}
-
-static inline void debug_yield_init(void)
-{
- rand_yield = time(NULL) ^ pthread_self();
-}
-#else
-static inline void debug_yield_read(void)
-{
-}
-
-static inline void debug_yield_write(void)
-{
-}
-
-static inline void debug_yield_init(void)
-{
-
-}
-#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 smp_mb_slave(int group)
-{
- cmm_smp_mb();
-}
-#endif
-
-#ifdef RCU_SIGNAL
-static inline void smp_mb_slave(int group)
-{
- cmm_barrier();
-}
-#endif
-
-/*
- * The trick here is that RCU_GP_CTR_PHASE 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.
- */
-#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(unsigned long) << 2))
-#define RCU_GP_CTR_NEST_MASK (RCU_GP_CTR_PHASE - 1)
-
-/*
- * Global quiescent period counter with low-order bits unused.
- * Using a int rather than a char to eliminate false register dependencies
- * causing stalls on some architectures.
- */
-extern unsigned long rcu_gp_ctr;
-
-struct rcu_reader {
- /* Data used by both reader and synchronize_rcu() */
- unsigned long ctr;
- char need_mb;
- /* Data used for registry */
- struct cds_list_head node __attribute__((aligned(CAA_CACHE_LINE_SIZE)));
- pthread_t tid;
-};
-
-extern struct rcu_reader __thread rcu_reader;
-
-extern int gp_futex;
-
-/*
- * Wake-up waiting synchronize_rcu(). Called from many concurrent threads.
- */
-static inline void wake_up_gp(void)
-{
- if (unlikely(uatomic_read(&gp_futex) == -1)) {
- uatomic_set(&gp_futex, 0);
- futex_async(&gp_futex, FUTEX_WAKE, 1,
- NULL, NULL, 0);
- }
-}
-
-static inline int rcu_gp_ongoing(unsigned long *ctr)
-{
- unsigned long v;
-
- /*
- * Make sure both tests below are done on the same version of *value
- * to insure consistency.
- */
- 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)
-{
- 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))) {
- _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 smp_mb_master().
- */
- smp_mb_slave(RCU_MB_GROUP);
- } else {
- _CMM_STORE_SHARED(rcu_reader.ctr, tmp + RCU_GP_COUNT);
- }
-}
-
-static inline void _rcu_read_unlock(void)
-{
- unsigned long tmp;
-
- tmp = rcu_reader.ctr;
- /*
- * Finish using rcu before decrementing the pointer.
- * See smp_mb_master().
- */
- if (likely((tmp & RCU_GP_CTR_NEST_MASK) == 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 */
- smp_mb_slave(RCU_MB_GROUP);
- wake_up_gp();
- } else {
- _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
-}
-#endif
-
-#endif /* _URCU_STATIC_H */
projects / urcu.git / blobdiff