+++ /dev/null
-#ifndef _URCU_BP_STATIC_H
-#define _URCU_BP_STATIC_H
-
-/*
- * urcu-bp-static.h
- *
- * Userspace RCU header.
- *
- * TO BE INCLUDED ONLY IN CODE THAT IS TO BE RECOMPILED ON EACH LIBURCU
- * RELEASE. 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 <unistd.h>
-
-#include <urcu/compiler.h>
-#include <urcu/arch.h>
-#include <urcu/system.h>
-#include <urcu/uatomic.h>
-#include <urcu/list.h>
-#include <urcu/tls-compat.h>
-#include <urcu/debug.h>
-
-/*
- * 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.
- */
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-enum rcu_state {
- RCU_READER_ACTIVE_CURRENT,
- RCU_READER_ACTIVE_OLD,
- RCU_READER_INACTIVE,
-};
-
-/*
- * 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(long) << 2))
-#define RCU_GP_CTR_NEST_MASK (RCU_GP_CTR_PHASE - 1)
-
-/*
- * Used internally by _rcu_read_lock.
- */
-extern void rcu_bp_register(void);
-
-struct rcu_gp {
- /*
- * Global grace period counter.
- * Contains the current RCU_GP_CTR_PHASE.
- * Also has a RCU_GP_COUNT of 1, to accelerate the reader fast path.
- * Written to only by writer with mutex taken.
- * Read by both writer and readers.
- */
- unsigned long ctr;
-} __attribute__((aligned(CAA_CACHE_LINE_SIZE)));
-
-extern struct rcu_gp rcu_gp;
-
-struct rcu_reader {
- /* Data used by both reader and synchronize_rcu() */
- unsigned long ctr;
- /* Data used for registry */
- struct cds_list_head node __attribute__((aligned(CAA_CACHE_LINE_SIZE)));
- pthread_t tid;
- int alloc; /* registry entry allocated */
-};
-
-/*
- * Bulletproof version keeps a pointer to a registry not part of the TLS.
- * Adds a pointer dereference on the read-side, but won't require to unregister
- * the reader thread.
- */
-extern DECLARE_URCU_TLS(struct rcu_reader *, rcu_reader);
-
-extern int urcu_bp_has_sys_membarrier;
-
-static inline void urcu_bp_smp_mb_slave(void)
-{
- if (caa_likely(urcu_bp_has_sys_membarrier))
- cmm_barrier();
- else
- cmm_smp_mb();
-}
-
-static inline enum rcu_state rcu_reader_state(unsigned long *ctr)
-{
- unsigned long v;
-
- if (ctr == NULL)
- return RCU_READER_INACTIVE;
- /*
- * Make sure both tests below are done on the same version of *value
- * to insure consistency.
- */
- v = CMM_LOAD_SHARED(*ctr);
- if (!(v & RCU_GP_CTR_NEST_MASK))
- return RCU_READER_INACTIVE;
- if (!((v ^ rcu_gp.ctr) & RCU_GP_CTR_PHASE))
- return RCU_READER_ACTIVE_CURRENT;
- return RCU_READER_ACTIVE_OLD;
-}
-
-/*
- * Helper for _rcu_read_lock(). The format of rcu_gp.ctr (as well as
- * the per-thread rcu_reader.ctr) has the upper bits containing a count of
- * _rcu_read_lock() nesting, and a lower-order bit that contains either zero
- * or RCU_GP_CTR_PHASE. The smp_mb_slave() ensures that the accesses in
- * _rcu_read_lock() happen before the subsequent read-side critical section.
- */
-static inline void _rcu_read_lock_update(unsigned long tmp)
-{
- if (caa_likely(!(tmp & RCU_GP_CTR_NEST_MASK))) {
- _CMM_STORE_SHARED(URCU_TLS(rcu_reader)->ctr, _CMM_LOAD_SHARED(rcu_gp.ctr));
- urcu_bp_smp_mb_slave();
- } else
- _CMM_STORE_SHARED(URCU_TLS(rcu_reader)->ctr, tmp + RCU_GP_COUNT);
-}
-
-/*
- * Enter an RCU read-side critical section.
- *
- * The first cmm_barrier() call ensures that the compiler does not reorder
- * the body of _rcu_read_lock() with a mutex.
- *
- * This function and its helper are both less than 10 lines long. The
- * intent is that this function meets the 10-line criterion in LGPL,
- * allowing this function to be invoked directly from non-LGPL code.
- */
-static inline void _rcu_read_lock(void)
-{
- unsigned long tmp;
-
- if (caa_unlikely(!URCU_TLS(rcu_reader)))
- rcu_bp_register(); /* If not yet registered. */
- cmm_barrier(); /* Ensure the compiler does not reorder us with mutex */
- tmp = URCU_TLS(rcu_reader)->ctr;
- urcu_assert((tmp & RCU_GP_CTR_NEST_MASK) != RCU_GP_CTR_NEST_MASK);
- _rcu_read_lock_update(tmp);
-}
-
-/*
- * Exit an RCU read-side critical section. This function is less than
- * 10 lines of code, and is intended to be usable by non-LGPL code, as
- * called out in LGPL.
- */
-static inline void _rcu_read_unlock(void)
-{
- unsigned long tmp;
-
- tmp = URCU_TLS(rcu_reader)->ctr;
- urcu_assert(tmp & RCU_GP_CTR_NEST_MASK);
- /* Finish using rcu before decrementing the pointer. */
- urcu_bp_smp_mb_slave();
- _CMM_STORE_SHARED(URCU_TLS(rcu_reader)->ctr, tmp - RCU_GP_COUNT);
- cmm_barrier(); /* Ensure the compiler does not reorder us with mutex */
-}
-
-/*
- * Returns whether within a RCU read-side critical section.
- *
- * This function is less than 10 lines long. The intent is that this
- * function meets the 10-line criterion for LGPL, allowing this function
- * to be invoked directly from non-LGPL code.
- */
-static inline int _rcu_read_ongoing(void)
-{
- if (caa_unlikely(!URCU_TLS(rcu_reader)))
- rcu_bp_register(); /* If not yet registered. */
- return URCU_TLS(rcu_reader)->ctr & RCU_GP_CTR_NEST_MASK;
-}
-
-#ifdef __cplusplus
-}
-#endif
-
-#endif /* _URCU_BP_STATIC_H */
projects / urcu.git / blobdiff