From: Mathieu Desnoyers Date: Sat, 9 Jul 2011 17:28:01 +0000 (-0400) Subject: rculfhash: wait for call_rcu quiescence before destroy X-Git-Tag: v0.7.0~43^2~207 X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=848d408839fe4f829db477644c776eba166a0e9a;p=userspace-rcu.git rculfhash: wait for call_rcu quiescence before destroy Signed-off-by: Mathieu Desnoyers --- diff --git a/rculfhash.c b/rculfhash.c index 556ec36..a3223f3 100644 --- a/rculfhash.c +++ b/rculfhash.c @@ -67,6 +67,7 @@ struct rcu_ht { ht_compare_fct compare_fct; unsigned long hash_seed; pthread_mutex_t resize_mutex; /* resize mutex: add/del mutex */ + unsigned int in_progress_resize; void (*ht_call_rcu)(struct rcu_head *head, void (*func)(struct rcu_head *head)); }; @@ -373,6 +374,7 @@ struct rcu_ht *ht_new(ht_hash_fct hash_fct, ht->compare_fct = compare_fct; ht->hash_seed = hash_seed; ht->ht_call_rcu = ht_call_rcu; + ht->in_progress_resize = 0; /* this mutex should not nest in read-side C.S. */ pthread_mutex_init(&ht->resize_mutex, NULL); ht->t = calloc(1, sizeof(struct rcu_table) @@ -477,6 +479,9 @@ int ht_destroy(struct rcu_ht *ht) { int ret; + /* Wait for in-flight resize operations to complete */ + while (uatomic_read(&ht->in_progress_resize)) + poll(NULL, 0, 100); /* wait for 100ms */ ret = ht_delete_dummy(ht); if (ret) return ret; @@ -576,6 +581,8 @@ void do_resize_cb(struct rcu_head *head) _do_ht_resize(ht); pthread_mutex_unlock(&ht->resize_mutex); free(work); + cmm_smp_mb(); /* finish resize before decrement */ + uatomic_dec(&ht->in_progress_resize); } static @@ -586,6 +593,8 @@ void ht_resize_lazy(struct rcu_ht *ht, struct rcu_table *t, int growth) target_size = resize_target_update(t, growth); if (!CMM_LOAD_SHARED(t->resize_initiated) && t->size < target_size) { + uatomic_inc(&ht->in_progress_resize); + cmm_smp_mb(); /* increment resize count before calling it */ work = malloc(sizeof(*work)); work->ht = ht; ht->ht_call_rcu(&work->head, do_resize_cb);