This patch introduces deferred event register/unregister mechanism. Newly added APIs are: - deferred_register_event(): thread safe register_event() - deferred_register_event_prio(): thread safe register_event_prio() - deferred_unregister_event(): thread safe unregister_event()
These functions can be called by worker threads safely. They allocate data structure which represents registering/unregistering event add queue it to the list shared with the main thread. After queuing, the main thread registers and unregisters events in a safe way. Signed-off-by: Hitoshi Mitake <[email protected]> --- include/event.h | 5 +++ lib/event.c | 132 ++++++++++++++++++++++++++++++++++++++++++++++++++------ 2 files changed, 124 insertions(+), 13 deletions(-) diff --git a/include/event.h b/include/event.h index 8f8b21f..b64b06e 100644 --- a/include/event.h +++ b/include/event.h @@ -32,4 +32,9 @@ static inline int register_event(int fd, event_handler_t h, void *data) return register_event_prio(fd, h, data, EVENT_PRIO_DEFAULT); } +void deferred_register_event_prio(int fd, event_handler_t h, void *data, + int prio); +void deferred_register_event(int fd, event_handler_t h, void *data); +void deferred_unregister_event(int fd); + #endif diff --git a/lib/event.c b/lib/event.c index 88078f4..2549dcd 100644 --- a/lib/event.c +++ b/lib/event.c @@ -76,19 +76,6 @@ static int event_cmp(const struct event_info *e1, const struct event_info *e2) return intcmp(e1->fd, e2->fd); } -int init_event(int nr) -{ - nr_events = nr; - events = xcalloc(nr_events, sizeof(struct epoll_event)); - - efd = epoll_create(nr); - if (efd < 0) { - sd_err("failed to create epoll fd"); - return -1; - } - return 0; -} - static struct event_info *lookup_event(int fd) { struct event_info key = { .fd = fd }; @@ -224,3 +211,122 @@ void event_loop_prio(int timeout) { do_event_loop(timeout, true); } + +struct deferred_event_info { + bool is_register; /* true: register, false: unregister */ + + int fd; + event_handler_t h; + void *data; + int prio; + + struct list_node list; +}; + +static LIST_HEAD(deferred_event_list); +static struct sd_mutex deferred_event_mutex = SD_MUTEX_INITIALIZER; + +static int deferred_event_fd; + +static void add_deferred_event_info(struct deferred_event_info *info) +{ + sd_mutex_lock(&deferred_event_mutex); + list_add_tail(&info->list, &deferred_event_list); + sd_mutex_unlock(&deferred_event_mutex); + + eventfd_xwrite(deferred_event_fd, 1); + event_force_refresh(); +} + +void deferred_register_event_prio(int fd, event_handler_t h, void *data, + int prio) +{ + struct deferred_event_info *info = xzalloc(sizeof(*info)); + + info->is_register = true; + + info->fd = fd; + info->h = h; + info->data = data; + info->prio = prio; + + add_deferred_event_info(info); +} + +void deferred_register_event(int fd, event_handler_t h, void *data) +{ + deferred_register_event_prio(fd, h, data, EVENT_PRIO_DEFAULT); +} + +void deferred_unregister_event(int fd) +{ + struct deferred_event_info *info = xzalloc(sizeof(*info)); + + info->is_register = false; + info->fd = fd; + + add_deferred_event_info(info); +} + +static void deferred_event_handler(int fd, int _events, void *data) +{ + LIST_HEAD(list); + + assert(fd == deferred_event_fd); + eventfd_xread(fd); + + sd_mutex_lock(&deferred_event_mutex); + list_splice_init(&deferred_event_list, &list); + sd_mutex_unlock(&deferred_event_mutex); + + while (!list_empty(&list)) { + int ret; + struct deferred_event_info *info; + + info = list_first_entry(&list, struct deferred_event_info, + list); + + if (info->is_register) { + ret = register_event_prio(info->fd, info->h, + info->data, info->prio); + if (ret < 0) + sd_err("failed to register event." + " fd: %d, handler: %p", + info->fd, info->h); + } else + unregister_event(info->fd); + + list_del(&info->list); + free(info); + } +} + +int init_event(int nr) +{ + int ret; + + nr_events = nr; + events = xcalloc(nr_events, sizeof(struct epoll_event)); + + efd = epoll_create(nr); + if (efd < 0) { + sd_err("failed to create epoll fd"); + return -1; + } + + deferred_event_fd = eventfd(0, EFD_NONBLOCK); + if (deferred_event_fd < 0) { + sd_err("failed to create eventfd for deferred event" + " register/unregister: %m"); + return -1; + } + + ret = register_event_prio(deferred_event_fd, deferred_event_handler, + NULL, EVENT_PRIO_MAX); + if (ret < 0) { + sd_err("failed to register deferred_event_handler()"); + return -1; + } + + return 0; +} -- 1.8.3.2 -- sheepdog mailing list [email protected] http://lists.wpkg.org/mailman/listinfo/sheepdog
