X-Git-Url: https://git.liburcu.org/?p=urcu.git;a=blobdiff_plain;f=urcu%2Fstatic%2Furcu-bp.h;fp=urcu%2Fstatic%2Furcu-bp.h;h=0000000000000000000000000000000000000000;hp=6e52d84bafe84f75dfd45593a2b58cad6431bcd0;hb=6893800a4d1cc14dff0395ddcd660a5138db183d;hpb=a59f39055b5ecb77b68cf78b9839aa9e8e4ec332 diff --git a/urcu/static/urcu-bp.h b/urcu/static/urcu-bp.h deleted file mode 100644 index 6e52d84..0000000 --- a/urcu/static/urcu-bp.h +++ /dev/null @@ -1,206 +0,0 @@ -#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 - * 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 -#include -#include - -#include -#include -#include -#include -#include -#include -#include - -/* - * 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 */