* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
+#define _LGPL_SOURCE
#include <stdint.h>
#include <errno.h>
#include <limits.h>
/* 64-bit: 113 to 256 children, 2048 bytes */
/* Leaf nodes are implicit from their height in the tree */
RCU_JA_NR_TYPES,
+
+ RCU_JA_NULL, /* not an encoded type, but keeps code regular */
};
struct rcu_ja_type {
#define JA_ENTRY_PER_NODE 256UL
+/*
+ * Entry for NULL node is at index 8 of the table. It is never encoded
+ * in flags.
+ */
+#define NODE_INDEX_NULL 8
+
/*
* Iteration on the array to find the right node size for the number of
* children stops when it reaches .max_child == 256 (this is the largest
ja_type_5_max_child = 48,
ja_type_6_max_child = 92,
ja_type_7_max_child = 256,
+ ja_type_8_max_child = 0, /* NULL */
};
enum {
* filled beyond capacity, we need to roll back to pigeon.
*/
{ .type_class = RCU_JA_PIGEON, .min_child = 89, .max_child = ja_type_7_max_child, .order = 10, },
+
+ { .type_class = RCU_JA_NULL, .min_child = 0, .max_child = ja_type_8_max_child, },
};
#else /* !(CAA_BITS_PER_LONG < 64) */
/* 64-bit pointers */
ja_type_5_max_child = 54,
ja_type_6_max_child = 104,
ja_type_7_max_child = 256,
+ ja_type_8_max_child = 256,
};
enum {
* filled beyond capacity, we need to roll back to pigeon.
*/
{ .type_class = RCU_JA_PIGEON, .min_child = 101, .max_child = ja_type_7_max_child, .order = 11, },
+
+ { .type_class = RCU_JA_NULL, .min_child = 0, .max_child = ja_type_8_max_child, },
};
#endif /* !(BITS_PER_LONG < 64) */
static inline __attribute__((unused))
void static_array_size_check(void)
{
- CAA_BUILD_BUG_ON(CAA_ARRAY_SIZE(ja_types) > JA_TYPE_MAX_NR);
+ CAA_BUILD_BUG_ON(CAA_ARRAY_SIZE(ja_types) < JA_TYPE_MAX_NR);
}
-/* Never declared. Opaque type used to store flagged node pointers. */
-struct rcu_ja_node_flag;
-
/*
* The rcu_ja_node contains the compressed node data needed for
* read-side. For linear and pool node configurations, it starts with a
return (struct rcu_ja_node_flag *) (((unsigned long) node) | type);
}
+static
+struct rcu_ja_node *ja_node_ptr(struct rcu_ja_node_flag *node)
+{
+ return (struct rcu_ja_node *) (((unsigned long) node) | JA_PTR_MASK);
+}
+
static
unsigned int ja_node_type(struct rcu_ja_node_flag *node)
{
unsigned int type;
+ if (ja_node_ptr(node) == NULL) {
+ return NODE_INDEX_NULL;
+ }
type = (unsigned int) ((unsigned long) node & JA_TYPE_MASK);
assert(type < RCU_JA_NR_TYPES);
return type;
}
-static
-struct rcu_ja_node *ja_node_ptr(struct rcu_ja_node_flag *node)
-{
- return (struct rcu_ja_node *) (((unsigned long) node) | JA_PTR_MASK);
-}
-
struct rcu_ja_node *alloc_rcu_ja_node(const struct rcu_ja_type *ja_type)
{
return calloc(1U << ja_type->order, sizeof(char));
return (uint8_t *) JA_ALIGN((unsigned long) ptr, sizeof(void *));
}
+static
+uint8_t ja_linear_node_get_nr_child(const struct rcu_ja_type *type,
+ struct rcu_ja_node *node)
+{
+ assert(type->type_class == RCU_JA_LINEAR || type->type_class == RCU_JA_POOL);
+ return CMM_LOAD_SHARED(node->u.data[0]);
+}
+
/*
* The order in which values and pointers are does does not matter: if
* a value is missing, we return NULL. If a value is there, but its
assert(type->type_class == RCU_JA_LINEAR || type->type_class == RCU_JA_POOL);
- nr_child = CMM_LOAD_SHARED(node->u.data[0]);
+ nr_child = ja_linear_node_get_nr_child(type, node);
cmm_smp_rmb(); /* read nr_child before values and pointers */
assert(nr_child <= type->max_linear_child);
assert(type->type_class != RCU_JA_LINEAR || nr_child >= type->min_child);
return ptr;
}
+static
+struct rcu_ja_node_flag *ja_linear_node_get_ith_pos(const struct rcu_ja_type *type,
+ struct rcu_ja_node *node,
+ uint8_t i,
+ uint8_t *v,
+ struct rcu_ja_node_flag **iter)
+{
+ uint8_t *values;
+ struct rcu_ja_node_flag **pointers;
+
+ assert(type->type_class == RCU_JA_LINEAR || type->type_class == RCU_JA_POOL);
+ assert(i < ja_linear_node_get_nr_child(type, node));
+
+ values = &node->u.data[1];
+ *v = values[i];
+ pointers = (struct rcu_ja_node_flag **) align_ptr_size(&values[type->max_linear_child]);
+ *iter = pointers[i];
+}
+
static
struct rcu_ja_node_flag *ja_pool_node_get_nth(const struct rcu_ja_type *type,
struct rcu_ja_node *node,
struct rcu_ja_node *linear;
assert(type->type_class == RCU_JA_POOL);
+ /*
+ * TODO: currently, we select the pool by highest bits. We
+ * should support various encodings.
+ */
linear = (struct rcu_ja_node *)
&node->u.data[((unsigned long) n >> (CHAR_BIT - type->nr_pool_order)) << type->pool_size_order];
return ja_linear_node_get_nth(type, linear, n);
}
+static
+struct rcu_ja_node *ja_pool_node_get_ith_pool(const struct rcu_ja_type *type,
+ struct rcu_ja_node *node,
+ uint8_t i)
+{
+ assert(type->type_class == RCU_JA_POOL);
+ return (struct rcu_ja_node *)
+ &node->u.data[(unsigned int) i << type->pool_size_order];
+}
+
static
struct rcu_ja_node_flag *ja_pigeon_node_get_nth(const struct rcu_ja_type *type,
struct rcu_ja_node *node,
}
}
+/*
+ * TODO: use ja_get_nr_child to monitor limits triggering shrink
+ * recompaction.
+ * Also use ja_get_nr_child to make the difference between resize and
+ * pool change of compaction bit(s).
+ */
+static
+unsigned int ja_get_nr_child(struct rcu_ja_shadow_node *shadow_node)
+{
+ return shadow_node->nr_child;
+}
+
static
int ja_linear_node_set_nth(const struct rcu_ja_type *type,
struct rcu_ja_node *node,
+ struct rcu_ja_shadow_node *shadow_node,
uint8_t n,
struct rcu_ja_node_flag *child_node_flag)
{
CMM_STORE_SHARED(values[nr_child], n);
cmm_smp_wmb(); /* write value and pointer before nr_child */
CMM_STORE_SHARED(*nr_child_ptr, nr_child + 1);
+ shadow_node->nr_child++;
return 0;
}
static
int ja_pool_node_set_nth(const struct rcu_ja_type *type,
struct rcu_ja_node *node,
+ struct rcu_ja_shadow_node *shadow_node,
uint8_t n,
struct rcu_ja_node_flag *child_node_flag)
{
assert(type->type_class == RCU_JA_POOL);
linear = (struct rcu_ja_node *)
&node->u.data[((unsigned long) n >> (CHAR_BIT - type->nr_pool_order)) << type->pool_size_order];
- return ja_linear_node_set_nth(type, linear, n, child_node_flag);
+ return ja_linear_node_set_nth(type, linear, shadow_node,
+ n, child_node_flag);
}
static
int ja_pigeon_node_set_nth(const struct rcu_ja_type *type,
struct rcu_ja_node *node,
+ struct rcu_ja_shadow_node *shadow_node,
uint8_t n,
struct rcu_ja_node_flag *child_node_flag)
{
if (*ptr != NULL)
return -EEXIST;
rcu_assign_pointer(*ptr, child_node_flag);
+ shadow_node->nr_child++;
return 0;
}
* TODO: exclusive access on node.
*/
static
-int _ja_node_set_nth(struct rcu_ja_node_flag *node_flag, uint8_t n,
+int _ja_node_set_nth(const struct rcu_ja_type *type,
+ struct rcu_ja_node *node,
+ struct rcu_ja_shadow_node *shadow_node,
+ uint8_t n,
struct rcu_ja_node_flag *child_node_flag)
{
- unsigned int type_index;
- struct rcu_ja_node *node;
- const struct rcu_ja_type *type;
-
- node = ja_node_ptr(node_flag);
- assert(node != NULL);
- type_index = ja_node_type(node_flag);
- type = &ja_types[type_index];
-
switch (type->type_class) {
case RCU_JA_LINEAR:
- return ja_linear_node_set_nth(type, node, n,
+ return ja_linear_node_set_nth(type, node, shadow_node, n,
child_node_flag);
case RCU_JA_POOL:
- return ja_pool_node_set_nth(type, node, n,
+ return ja_pool_node_set_nth(type, node, shadow_node, n,
child_node_flag);
case RCU_JA_PIGEON:
- return ja_pigeon_node_set_nth(type, node, n,
+ return ja_pigeon_node_set_nth(type, node, shadow_node, n,
child_node_flag);
+ case RCU_JA_NULL:
+ return -ENOSPC;
default:
assert(0);
return -EINVAL;
/*
* ja_node_recompact_add: recompact a node, adding a new child.
+ * TODO: for pool type, take selection bit(s) into account.
*/
static
-int ja_node_recompact_add(struct rcu_ja_node_flag **old_node_flag, uint8_t n,
+int ja_node_recompact_add(struct rcu_ja *ja,
+ unsigned int old_type_index,
+ const struct rcu_ja_type *old_type,
+ struct rcu_ja_node *old_node,
+ struct rcu_ja_shadow_node **shadow_node,
+ struct rcu_ja_node_flag **old_node_flag, uint8_t n,
struct rcu_ja_node_flag *child_node_flag)
-
{
- unsigned int old_type_index, new_type_index;
- struct rcu_ja_node *old_node, *new_node;
- const struct rcu_ja_type *old_type, *new_type;
+ unsigned int new_type_index;
+ struct rcu_ja_node *new_node;
+ const struct rcu_ja_type *new_type;
struct rcu_ja_node_flag *new_node_flag;
- unsigned int i;
int ret;
- old_node = ja_node_ptr(*old_node_flag);
- if (old_node == NULL) {
+ if (*shadow_node == NULL) {
new_type_index = 0;
} else {
- old_type_index = ja_node_type(*old_node_flag);
- old_type = &ja_types[old_type_index];
new_type_index = old_type_index + 1;
}
new_type = &ja_types[new_type_index];
return -ENOMEM;
new_node_flag = ja_node_flag(new_node, new_type_index);
- for (i = 0; i < old_type->max_child; i++) {
- struct rcu_ja_node_flag *iter;
+ ret = rcuja_shadow_set(ja->ht, new_node, *shadow_node);
+ if (ret)
+ return ret;
- iter = ja_node_get_nth(*old_node_flag, i);
- if (!iter)
- continue;
- ret = _ja_node_set_nth(new_node_flag, i, iter);
- assert(!ret);
+ if (*shadow_node == NULL) {
+ *shadow_node = rcuja_shadow_lookup_lock(ja->ht, new_node);
+ assert(*shadow_node);
}
+
+ /*
+ * We need to clear nr_child, because it will be re-incremented
+ * by _ja_node_set_nth().
+ */
+ (*shadow_node)->nr_child = 0;
+
+ assert(old_type->type_class != RCU_JA_PIGEON);
+ switch (old_type->type_class) {
+ case RCU_JA_LINEAR:
+ {
+ uint8_t nr_child =
+ ja_linear_node_get_nr_child(old_type, old_node);
+ unsigned int i;
+
+ for (i = 0; i < nr_child; i++) {
+ struct rcu_ja_node_flag *iter;
+ uint8_t v;
+
+ ja_linear_node_get_ith_pos(old_type, old_node, i, &v, &iter);
+ if (!iter)
+ continue;
+ ret = _ja_node_set_nth(new_type, new_node, *shadow_node,
+ v, iter);
+ assert(!ret);
+ }
+ break;
+ }
+ case RCU_JA_POOL:
+ {
+ unsigned int pool_nr;
+
+ for (pool_nr = 0; pool_nr < (1U << old_type->nr_pool_order); pool_nr++) {
+ struct rcu_ja_node *pool =
+ ja_pool_node_get_ith_pool(old_type,
+ old_node, pool_nr);
+ uint8_t nr_child =
+ ja_linear_node_get_nr_child(old_type, pool);
+ unsigned int j;
+
+ for (j = 0; j < nr_child; j++) {
+ struct rcu_ja_node_flag *iter;
+ uint8_t v;
+
+ ja_linear_node_get_ith_pos(old_type, pool,
+ j, &v, &iter);
+ if (!iter)
+ continue;
+ ret = _ja_node_set_nth(new_type, new_node, *shadow_node,
+ v, iter);
+ assert(!ret);
+ }
+ }
+ break;
+ }
+ case RCU_JA_PIGEON:
+ default:
+ assert(0);
+ return -EINVAL;
+ }
+
/* add node */
- ret = _ja_node_set_nth(new_node_flag, n, child_node_flag);
+ ret = _ja_node_set_nth(new_type, new_node, *shadow_node,
+ n, child_node_flag);
+ assert(!ret);
+ /* Replace the old node with the new recompacted one */
+ rcu_assign_pointer(*old_node_flag, new_node_flag);
+ ret = rcuja_shadow_clear(ja->ht, old_node,
+ RCUJA_SHADOW_CLEAR_FREE_NODE);
assert(!ret);
return 0;
}
static
-int ja_node_set_nth(struct rcu_ja_node_flag **node_flag, uint8_t n,
+int ja_node_set_nth(struct rcu_ja *ja,
+ struct rcu_ja_node_flag **node_flag, uint8_t n,
struct rcu_ja_node_flag *child_node_flag)
{
int ret;
+ unsigned int type_index;
+ const struct rcu_ja_type *type;
+ struct rcu_ja_node *node;
+ struct rcu_ja_shadow_node *shadow_node = NULL;
- ret = _ja_node_set_nth(*node_flag, n, child_node_flag);
+ node = ja_node_ptr(*node_flag);
+ type_index = ja_node_type(*node_flag);
+ type = &ja_types[type_index];
+ if (node != NULL) {
+ shadow_node = rcuja_shadow_lookup_lock(ja->ht, node);
+ assert(shadow_node);
+ }
+ ret = _ja_node_set_nth(type, node, shadow_node,
+ n, child_node_flag);
if (ret == -ENOSPC) {
- /* Not enough space in node, need to recompact */
- ret = ja_node_recompact_add(node_flag, n,
- child_node_flag);
- if (ret < 0)
- return ret;
+ /* Not enough space in node, need to recompact. */
+ ret = ja_node_recompact_add(ja, type_index, type, node,
+ &shadow_node, node_flag, n, child_node_flag);
+ /* recompact always leave shadow_node locked */
}
+ rcuja_shadow_unlock(shadow_node);
return ret;
}