X-Git-Url: http://git.liburcu.org/?p=urcu.git;a=blobdiff_plain;f=doc%2Frcu-api.txt;fp=doc%2Frcu-api.txt;h=0000000000000000000000000000000000000000;hp=b64731671e3a78fd15b669e9927f646f45235852;hb=dcb9c05a081e2c8d4fe0250f3700e3efb1200cac;hpb=2fec8f05f010408e989356e6f9d8c1e191ba4dfa diff --git a/doc/rcu-api.txt b/doc/rcu-api.txt deleted file mode 100644 index b647316..0000000 --- a/doc/rcu-api.txt +++ /dev/null @@ -1,171 +0,0 @@ -Userspace RCU API -by Mathieu Desnoyers and Paul E. McKenney - - -void rcu_init(void); - - This must be called before any of the following functions - are invoked. - -void rcu_read_lock(void); - - Begin an RCU read-side critical section. These critical - sections may be nested. - -void rcu_read_unlock(void); - - End an RCU read-side critical section. - -void rcu_register_thread(void); - - Each thread must invoke this function before its first call to - rcu_read_lock(). Threads that never call rcu_read_lock() need - not invoke this function. In addition, rcu-bp ("bullet proof" - RCU) does not require any thread to invoke rcu_register_thread(). - -void rcu_unregister_thread(void); - - Each thread that invokes rcu_register_thread() must invoke - rcu_unregister_thread() before invoking pthread_exit() - or before returning from its top-level function. - -void synchronize_rcu(void); - - Wait until every pre-existing RCU read-side critical section - has completed. Note that this primitive will not necessarily - wait for RCU read-side critical sections that have not yet - started: this is not a reader-writer lock. The duration - actually waited is called an RCU grace period. - -void call_rcu(struct rcu_head *head, - void (*func)(struct rcu_head *head)); - - Registers the callback indicated by "head". This means - that "func" will be invoked after the end of a future - RCU grace period. The rcu_head structure referenced - by "head" will normally be a field in a larger RCU-protected - structure. A typical implementation of "func" is as - follows: - - void func(struct rcu_head *head) - { - struct foo *p = container_of(head, struct foo, rcu); - - free(p); - } - - This RCU callback function can be registered as follows - given a pointer "p" to the enclosing structure: - - call_rcu(&p->rcu, func); - - call_rcu should be called from registered RCU read-side threads. - For the QSBR flavor, the caller should be online. - -void rcu_barrier(void); - - Wait for all call_rcu() work initiated prior to rcu_barrier() by - _any_ thread on the system to have completed before rcu_barrier() - returns. rcu_barrier() should never be called from a call_rcu() - thread. This function can be used, for instance, to ensure that - all memory reclaim involving a shared object has completed - before allowing dlclose() of this shared object to complete. - -struct call_rcu_data *create_call_rcu_data(unsigned long flags, - int cpu_affinity); - - Returns a handle that can be passed to the following - primitives. The "flags" argument can be zero, or can be - URCU_CALL_RCU_RT if the worker threads associated with the - new helper thread are to get real-time response. The argument - "cpu_affinity" specifies a cpu on which the call_rcu thread should - be affined to. It is ignored if negative. - -void call_rcu_data_free(struct call_rcu_data *crdp); - - Terminates a call_rcu() helper thread and frees its associated - data. The caller must have ensured that this thread is no longer - in use, for example, by passing NULL to set_thread_call_rcu_data() - and set_cpu_call_rcu_data() as required. - -struct call_rcu_data *get_default_call_rcu_data(void); - - Returns the handle for the default call_rcu() helper thread. - Creates it if necessary. - -struct call_rcu_data *get_cpu_call_rcu_data(int cpu); - - Returns the handle for the current cpu's call_rcu() helper - thread, or NULL if the current CPU has no helper thread - currently assigned. The call to this function and use of the - returned call_rcu_data should be protected by RCU read-side - lock. - -struct call_rcu_data *get_thread_call_rcu_data(void); - - Returns the handle for the current thread's hard-assigned - call_rcu() helper thread, or NULL if the current thread is - instead using a per-CPU or the default helper thread. - -struct call_rcu_data *get_call_rcu_data(void); - - Returns the handle for the current thread's call_rcu() helper - thread, which is either, in increasing order of preference: - per-thread hard-assigned helper thread, per-cpu helper thread, - or default helper thread. get_call_rcu_data should be called - from registered RCU read-side threads. For the QSBR flavor, the - caller should be online. - -pthread_t get_call_rcu_thread(struct call_rcu_data *crdp); - - Returns the helper thread's pthread identifier linked to a call - rcu helper thread data. - -void set_thread_call_rcu_data(struct call_rcu_data *crdp); - - Sets the current thread's hard-assigned call_rcu() helper to the - handle specified by "crdp". Note that "crdp" can be NULL to - disassociate this thread from its helper. Once a thread is - disassociated from its helper, further call_rcu() invocations - use the current CPU's helper if there is one and the default - helper otherwise. - -int set_cpu_call_rcu_data(int cpu, struct call_rcu_data *crdp); - - Sets the specified CPU's call_rcu() helper to the handle - specified by "crdp". Again, "crdp" can be NULL to disassociate - this CPU from its helper thread. Once a CPU has been - disassociated from its helper, further call_rcu() invocations - that would otherwise have used this CPU's helper will instead - use the default helper. The caller must wait for a grace-period - to pass between return from set_cpu_call_rcu_data() and call to - call_rcu_data_free() passing the previous call rcu data as - argument. - -int create_all_cpu_call_rcu_data(unsigned long flags) - - Creates a separate call_rcu() helper thread for each CPU. - After this primitive is invoked, the global default call_rcu() - helper thread will not be called. - - The set_thread_call_rcu_data(), set_cpu_call_rcu_data(), and - create_all_cpu_call_rcu_data() functions may be combined to set up - pretty much any desired association between worker and call_rcu() - helper threads. If a given executable calls only call_rcu(), - then that executable will have only the single global default - call_rcu() helper thread. This will suffice in most cases. - -void free_all_cpu_call_rcu_data(void); - - Clean up all the per-CPU call_rcu threads. Should be paired with - create_all_cpu_call_rcu_data() to perform teardown. Note that - this function invokes synchronize_rcu() internally, so the - caller should be careful not to hold mutexes (or mutexes within a - dependency chain) that are also taken within a RCU read-side - critical section, or in a section where QSBR threads are online. - -void call_rcu_after_fork_child(void); - - Should be used as pthread_atfork() handler for programs using - call_rcu and performing fork() or clone() without a following - exec().