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authorAndy Wingo <wingo@pobox.com>2012-02-17 11:47:52 +0100
committerAndy Wingo <wingo@pobox.com>2012-02-17 12:09:28 +0100
commitf609480611cfd1585409fd6b1b90beb730b026cf (patch)
treeae054e365a2980bf9836447ba4cd9bf6c0f88e72 /libguile/weak-table.c
parent58565208bdfe7544f7e4da8762e4c331171f9876 (diff)
downloadguile-f609480611cfd1585409fd6b1b90beb730b026cf.tar.gz
with a threaded guile, lock weak sets and tables during a fork
* libguile/weak-set.c (make_weak_set): * libguile/weak-table.c (make_weak_table): If we have a threaded Guile, * keep a weak set (table) of weak sets (tables). Use this and the pthread_atfork mechanism to lock and unlock weak sets and weak tables during a fork(). * libguile/weak-set.h (scm_weak_set_prehistory): New internal API. * libguile/init.c: Add call to scm_weak_set_prehistory().
Diffstat (limited to 'libguile/weak-table.c')
-rw-r--r--libguile/weak-table.c108
1 files changed, 94 insertions, 14 deletions
diff --git a/libguile/weak-table.c b/libguile/weak-table.c
index 38fd23d30..3d453bafd 100644
--- a/libguile/weak-table.c
+++ b/libguile/weak-table.c
@@ -736,10 +736,79 @@ weak_table_remove_x (scm_t_weak_table *table, unsigned long hash,
+
+static void
+lock_weak_table (scm_t_weak_table *table)
+{
+ scm_i_pthread_mutex_lock (&table->lock);
+}
+
+static void
+unlock_weak_table (scm_t_weak_table *table)
+{
+ scm_i_pthread_mutex_unlock (&table->lock);
+}
+
+/* A weak table of weak tables, for use in the pthread_atfork handler. */
+static SCM all_weak_tables = SCM_BOOL_F;
+
+#if SCM_USE_PTHREAD_THREADS
+
+static void
+lock_all_weak_tables (void)
+{
+ scm_t_weak_table *s;
+ scm_t_weak_entry *entries;
+ unsigned long k, size;
+ scm_t_weak_entry copy;
+
+ s = SCM_WEAK_TABLE (all_weak_tables);
+ lock_weak_table (s);
+ size = s->size;
+ entries = s->entries;
+
+ for (k = 0; k < size; k++)
+ if (entries[k].hash)
+ {
+ copy_weak_entry (&entries[k], &copy);
+ if (copy.key)
+ lock_weak_table (SCM_WEAK_TABLE (SCM_PACK (copy.key)));
+ }
+}
+
+static void
+unlock_all_weak_tables (void)
+{
+ scm_t_weak_table *s;
+ scm_t_weak_entry *entries;
+ unsigned long k, size;
+ scm_t_weak_entry copy;
+
+ s = SCM_WEAK_TABLE (all_weak_tables);
+ size = s->size;
+ entries = s->entries;
+
+ for (k = 0; k < size; k++)
+ if (entries[k].hash)
+ {
+ copy_weak_entry (&entries[k], &copy);
+ if (copy.key)
+ unlock_weak_table (SCM_WEAK_TABLE (SCM_PACK (copy.key)));
+ }
+
+ unlock_weak_table (s);
+}
+
+#endif /* SCM_USE_PTHREAD_THREADS */
+
+
+
+
static SCM
make_weak_table (unsigned long k, scm_t_weak_table_kind kind)
{
scm_t_weak_table *table;
+ SCM ret;
int i = 0, n = k ? k : 31;
while (i + 1 < HASHTABLE_SIZE_N && n > hashtable_size[i])
@@ -757,7 +826,12 @@ make_weak_table (unsigned long k, scm_t_weak_table_kind kind)
table->min_size_index = i;
scm_i_pthread_mutex_init (&table->lock, NULL);
- return scm_cell (scm_tc7_weak_table, (scm_t_bits)table);
+ ret = scm_cell (scm_tc7_weak_table, (scm_t_bits)table);
+
+ if (scm_is_true (all_weak_tables))
+ scm_weak_table_putq_x (all_weak_tables, ret, SCM_BOOL_T);
+
+ return ret;
}
void
@@ -781,7 +855,7 @@ do_vacuum_weak_table (SCM table)
if (scm_i_pthread_mutex_trylock (&t->lock) == 0)
{
vacuum_weak_table (t);
- scm_i_pthread_mutex_unlock (&t->lock);
+ unlock_weak_table (t);
}
return;
@@ -868,11 +942,11 @@ scm_c_weak_table_ref (SCM table, unsigned long raw_hash,
t = SCM_WEAK_TABLE (table);
- scm_i_pthread_mutex_lock (&t->lock);
+ lock_weak_table (t);
ret = weak_table_ref (t, raw_hash, pred, closure, dflt);
- scm_i_pthread_mutex_unlock (&t->lock);
+ unlock_weak_table (t);
return ret;
}
@@ -890,11 +964,11 @@ scm_c_weak_table_put_x (SCM table, unsigned long raw_hash,
t = SCM_WEAK_TABLE (table);
- scm_i_pthread_mutex_lock (&t->lock);
+ lock_weak_table (t);
weak_table_put_x (t, raw_hash, pred, closure, key, value);
- scm_i_pthread_mutex_unlock (&t->lock);
+ unlock_weak_table (t);
}
#undef FUNC_NAME
@@ -910,11 +984,11 @@ scm_c_weak_table_remove_x (SCM table, unsigned long raw_hash,
t = SCM_WEAK_TABLE (table);
- scm_i_pthread_mutex_lock (&t->lock);
+ lock_weak_table (t);
weak_table_remove_x (t, raw_hash, pred, closure);
- scm_i_pthread_mutex_unlock (&t->lock);
+ unlock_weak_table (t);
}
#undef FUNC_NAME
@@ -962,12 +1036,12 @@ scm_weak_table_clear_x (SCM table)
t = SCM_WEAK_TABLE (table);
- scm_i_pthread_mutex_lock (&t->lock);
+ lock_weak_table (t);
memset (t->entries, 0, sizeof (scm_t_weak_entry) * t->size);
t->n_items = 0;
- scm_i_pthread_mutex_unlock (&t->lock);
+ unlock_weak_table (t);
return SCM_UNSPECIFIED;
}
@@ -983,7 +1057,7 @@ scm_c_weak_table_fold (scm_t_table_fold_fn proc, void *closure,
t = SCM_WEAK_TABLE (table);
- scm_i_pthread_mutex_lock (&t->lock);
+ lock_weak_table (t);
size = t->size;
entries = t->entries;
@@ -999,16 +1073,16 @@ scm_c_weak_table_fold (scm_t_table_fold_fn proc, void *closure,
if (copy.key && copy.value)
{
/* Release table lock while we call the function. */
- scm_i_pthread_mutex_unlock (&t->lock);
+ unlock_weak_table (t);
init = proc (closure,
SCM_PACK (copy.key), SCM_PACK (copy.value),
init);
- scm_i_pthread_mutex_lock (&t->lock);
+ lock_weak_table (t);
}
}
}
- scm_i_pthread_mutex_unlock (&t->lock);
+ unlock_weak_table (t);
return init;
}
@@ -1163,6 +1237,12 @@ scm_weak_table_prehistory (void)
GC_new_kind (GC_new_free_list (),
GC_MAKE_PROC (GC_new_proc (mark_weak_value_table), 0),
0, 0);
+
+#if SCM_USE_PTHREAD_THREADS
+ all_weak_tables = scm_c_make_weak_table (0, SCM_WEAK_TABLE_KIND_KEY);
+ pthread_atfork (lock_all_weak_tables, unlock_all_weak_tables,
+ unlock_all_weak_tables);
+#endif
}
void