rculfhash test: add missing call_rcu per-cpu worker threads teardown

[urcu.git] / rculfhash.c

diff --git a/rculfhash.c b/rculfhash.c
index 6a80049ddd1f783a21e117d63437eec5771ba514..4080e8e54b9ee87a6cbccb93fbea49cd0901b3b3 100644 (file)
--- a/rculfhash.c
+++ b/rculfhash.c
@@ -156,9 +156,6 @@
 #define dbg_printf(fmt, args...)
 #endif
 
-/* For testing */
-#define POISON_FREE
-
 /*
  * Per-CPU split-counters lazily update the global counter each 1024
  * addition/removal. It automatically keeps track of resize required.
@@ -220,6 +217,8 @@ struct cds_lfht {
        void (*cds_lfht_call_rcu)(struct rcu_head *head,
                      void (*func)(struct rcu_head *head));
        void (*cds_lfht_synchronize_rcu)(void);
+       void (*cds_lfht_rcu_read_lock)(void);
+       void (*cds_lfht_rcu_read_unlock)(void);
        unsigned long count;            /* global approximate item count */
        struct ht_items_count *percpu_count;    /* per-cpu item count */
 };
@@ -675,20 +674,15 @@ static
 void _cds_lfht_gc_bucket(struct cds_lfht_node *dummy, struct cds_lfht_node *node)
 {
        struct cds_lfht_node *iter_prev, *iter, *next, *new_next;
-       struct cds_lfht_node *iter_trace[64];
-       unsigned long trace_idx = 0;
 
-       memset(iter_trace, 0, sizeof(iter_trace));
        assert(!is_dummy(dummy));
        assert(!is_removed(dummy));
        assert(!is_dummy(node));
        assert(!is_removed(node));
        for (;;) {
-               iter_trace[trace_idx++ & (64 - 1)] = (void *) 0x1;
                iter_prev = dummy;
                /* We can always skip the dummy node initially */
                iter = rcu_dereference(iter_prev->p.next);
-               iter_trace[trace_idx++ & (64 - 1)] = iter;
                assert(iter_prev->p.reverse_hash <= node->p.reverse_hash);
                /*
                 * We should never be called with dummy (start of chain)
@@ -707,7 +701,6 @@ void _cds_lfht_gc_bucket(struct cds_lfht_node *dummy, struct cds_lfht_node *node
                                break;
                        iter_prev = clear_flag(iter);
                        iter = next;
-                       iter_trace[trace_idx++ & (64 - 1)] = iter;
                }
                assert(!is_removed(iter));
                if (is_dummy(iter))
@@ -715,7 +708,6 @@ void _cds_lfht_gc_bucket(struct cds_lfht_node *dummy, struct cds_lfht_node *node
                else
                        new_next = clear_flag(next);
                (void) uatomic_cmpxchg(&iter_prev->p.next, iter, new_next);
-               iter_trace[trace_idx++ & (64 - 1)] = (void *) 0x2;
        }
 }
 
@@ -862,6 +854,11 @@ end:
                return -ENOENT;
 }
 
+/*
+ * Holding RCU read lock to protect _cds_lfht_add against memory
+ * reclaim that could be performed by other call_rcu worker threads (ABA
+ * problem).
+ */
 static
 void init_table(struct cds_lfht *ht, struct rcu_table *t,
                unsigned long first_order, unsigned long len_order)
@@ -879,6 +876,7 @@ void init_table(struct cds_lfht *ht, struct rcu_table *t,
                dbg_printf("init order %lu len: %lu\n", i, len);
                t->tbl[i] = calloc(1, sizeof(struct rcu_level)
                                + (len * sizeof(struct _cds_lfht_node)));
+               ht->cds_lfht_rcu_read_lock();
                for (j = 0; j < len; j++) {
                        struct cds_lfht_node *new_node =
                                (struct cds_lfht_node *) &t->tbl[i]->nodes[j];
@@ -891,6 +889,7 @@ void init_table(struct cds_lfht *ht, struct rcu_table *t,
                        if (CMM_LOAD_SHARED(ht->in_progress_destroy))
                                break;
                }
+               ht->cds_lfht_rcu_read_unlock();
                /* Update table size */
                t->size = !i ? 1 : (1UL << i);
                dbg_printf("init new size: %lu\n", t->size);
@@ -901,6 +900,11 @@ void init_table(struct cds_lfht *ht, struct rcu_table *t,
        t->resize_initiated = 0;
 }
 
+/*
+ * Holding RCU read lock to protect _cds_lfht_remove against memory
+ * reclaim that could be performed by other call_rcu worker threads (ABA
+ * problem).
+ */
 static
 void fini_table(struct cds_lfht *ht, struct rcu_table *t,
                unsigned long first_order, unsigned long len_order)
@@ -924,6 +928,7 @@ void fini_table(struct cds_lfht *ht, struct rcu_table *t,
                 */
                t->size = 1UL << (i - 1);
                /* Unlink */
+               ht->cds_lfht_rcu_read_lock();
                for (j = 0; j < len; j++) {
                        struct cds_lfht_node *fini_node =
                                (struct cds_lfht_node *) &t->tbl[i]->nodes[j];
@@ -936,6 +941,7 @@ void fini_table(struct cds_lfht *ht, struct rcu_table *t,
                        if (CMM_LOAD_SHARED(ht->in_progress_destroy))
                                break;
                }
+               ht->cds_lfht_rcu_read_unlock();
                ht->cds_lfht_call_rcu(&t->tbl[i]->head, cds_lfht_free_level);
                dbg_printf("fini new size: %lu\n", t->size);
                if (CMM_LOAD_SHARED(ht->in_progress_destroy))
@@ -952,7 +958,9 @@ struct cds_lfht *cds_lfht_new(cds_lfht_hash_fct hash_fct,
                        int flags,
                        void (*cds_lfht_call_rcu)(struct rcu_head *head,
                                        void (*func)(struct rcu_head *head)),
-                       void (*cds_lfht_synchronize_rcu)(void))
+                       void (*cds_lfht_synchronize_rcu)(void),
+                       void (*cds_lfht_rcu_read_lock)(void),
+                       void (*cds_lfht_rcu_read_unlock)(void))
 {
        struct cds_lfht *ht;
        unsigned long order;
@@ -966,6 +974,8 @@ struct cds_lfht *cds_lfht_new(cds_lfht_hash_fct hash_fct,
        ht->hash_seed = hash_seed;
        ht->cds_lfht_call_rcu = cds_lfht_call_rcu;
        ht->cds_lfht_synchronize_rcu = cds_lfht_synchronize_rcu;
+       ht->cds_lfht_rcu_read_lock = cds_lfht_rcu_read_lock;
+       ht->cds_lfht_rcu_read_unlock = cds_lfht_rcu_read_unlock;
        ht->in_progress_resize = 0;
        ht->percpu_count = alloc_per_cpu_items_count();
        /* this mutex should not nest in read-side C.S. */