#include <urcu/arch.h>
#include <assert.h>
#include <urcu-pointer.h>
+#include <urcu/uatomic.h>
#include <stdint.h>
#include "rcuja-internal.h"
* child type.
*/
#define JA_TYPE_BITS 3
-#define JA_TYPE_MAX_NR (1U << JA_TYPE_BITS)
+#define JA_TYPE_MAX_NR (1UL << JA_TYPE_BITS)
#define JA_TYPE_MASK (JA_TYPE_MAX_NR - 1)
#define JA_PTR_MASK (~JA_TYPE_MASK)
#define JA_ENTRY_PER_NODE 256UL
#define JA_BITS_PER_BYTE 3
+#define JA_MAX_DEPTH 5 /* Maximum depth, including leafs */
+
/*
* Entry for NULL node is at index 8 of the table. It is never encoded
* in flags.
*/
#define NODE_INDEX_NULL 8
+/*
+ * Number of removals needed on a fallback node before we try to shrink
+ * it.
+ */
+#define JA_FALLBACK_REMOVAL_COUNT 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
static
struct cds_ja_inode_flag *ja_node_flag(struct cds_ja_inode *node,
- unsigned int type)
+ unsigned long type)
{
- assert(type < RCU_JA_NR_TYPES);
+ assert(type < (1UL << JA_TYPE_BITS));
return (struct cds_ja_inode_flag *) (((unsigned long) node) | type);
}
static
struct cds_ja_inode *ja_node_ptr(struct cds_ja_inode_flag *node)
{
- return (struct cds_ja_inode *) (((unsigned long) node) | JA_PTR_MASK);
+ return (struct cds_ja_inode *) (((unsigned long) node) & JA_PTR_MASK);
}
static
-unsigned int ja_node_type(struct cds_ja_inode_flag *node)
+unsigned long ja_node_type(struct cds_ja_inode_flag *node)
{
- unsigned int type;
+ unsigned long 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);
+ assert(type < (1UL << JA_TYPE_BITS));
return type;
}
static
struct cds_ja_inode_flag *ja_linear_node_get_nth(const struct cds_ja_type *type,
struct cds_ja_inode *node,
+ struct cds_ja_inode_flag ***child_node_flag_ptr,
uint8_t n)
{
uint8_t nr_child;
if (i >= nr_child)
return NULL;
pointers = (struct cds_ja_inode_flag **) align_ptr_size(&values[type->max_linear_child]);
+ if (caa_unlikely(child_node_flag_ptr))
+ *child_node_flag_ptr = &pointers[i];
ptr = rcu_dereference(pointers[i]);
assert(ja_node_ptr(ptr) != NULL);
return ptr;
}
static
-struct cds_ja_inode_flag *ja_linear_node_get_ith_pos(const struct cds_ja_type *type,
+void ja_linear_node_get_ith_pos(const struct cds_ja_type *type,
struct cds_ja_inode *node,
uint8_t i,
uint8_t *v,
static
struct cds_ja_inode_flag *ja_pool_node_get_nth(const struct cds_ja_type *type,
struct cds_ja_inode *node,
+ struct cds_ja_inode_flag ***child_node_flag_ptr,
uint8_t n)
{
struct cds_ja_inode *linear;
*/
linear = (struct cds_ja_inode *)
&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);
+ return ja_linear_node_get_nth(type, linear, child_node_flag_ptr, n);
}
static
static
struct cds_ja_inode_flag *ja_pigeon_node_get_nth(const struct cds_ja_type *type,
struct cds_ja_inode *node,
+ struct cds_ja_inode_flag ***child_node_flag_ptr,
uint8_t n)
{
+ struct cds_ja_inode_flag **child_node_flag;
+
assert(type->type_class == RCU_JA_PIGEON);
- return rcu_dereference(((struct cds_ja_inode_flag **) node->u.data)[n]);
+ child_node_flag = &((struct cds_ja_inode_flag **) node->u.data)[n];
+ if (caa_unlikely(child_node_flag_ptr))
+ *child_node_flag_ptr = child_node_flag;
+ return rcu_dereference(*child_node_flag);
}
/*
*/
static
struct cds_ja_inode_flag * ja_node_get_nth(struct cds_ja_inode_flag *node_flag,
+ struct cds_ja_inode_flag ***child_node_flag_ptr,
uint8_t n)
{
unsigned int type_index;
const struct cds_ja_type *type;
node = ja_node_ptr(node_flag);
- if (caa_unlikely(node == NULL))
- return NULL;
+ 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_get_nth(type, node, n);
+ return ja_linear_node_get_nth(type, node,
+ child_node_flag_ptr, n);
case RCU_JA_POOL:
- return ja_pool_node_get_nth(type, node, n);
+ return ja_pool_node_get_nth(type, node,
+ child_node_flag_ptr, n);
case RCU_JA_PIGEON:
- return ja_pigeon_node_get_nth(type, node, n);
+ return ja_pigeon_node_get_nth(type, node,
+ child_node_flag_ptr, n);
default:
assert(0);
return (void *) -1UL;
assert(type->type_class == RCU_JA_LINEAR || type->type_class == RCU_JA_POOL);
nr_child_ptr = &node->u.data[0];
+ dbg_printf("linear set nth: nr_child_ptr %p\n", nr_child_ptr);
nr_child = *nr_child_ptr;
assert(nr_child <= type->max_linear_child);
- assert(type->type_class != RCU_JA_LINEAR || nr_child >= type->min_child);
values = &node->u.data[1];
for (i = 0; i < nr_child; i++) {
cmm_smp_wmb(); /* write value and pointer before nr_child */
CMM_STORE_SHARED(*nr_child_ptr, nr_child + 1);
shadow_node->nr_child++;
+ dbg_printf("linear set nth: %u child, shadow: %u child, for node %p shadow %p\n",
+ (unsigned int) CMM_LOAD_SHARED(*nr_child_ptr),
+ (unsigned int) shadow_node->nr_child,
+ node, shadow_node);
+
return 0;
}
assert(type->type_class == RCU_JA_PIGEON);
ptr = &((struct cds_ja_inode_flag **) node->u.data)[n];
- if (*ptr != NULL)
+ if (*ptr)
return -EEXIST;
rcu_assign_pointer(*ptr, child_node_flag);
shadow_node->nr_child++;
/*
* ja_node_recompact_add: recompact a node, adding a new child.
* TODO: for pool type, take selection bit(s) into account.
+ * Return 0 on success, -ENOENT if need to retry, or other negative
+ * error value otherwise.
*/
static
int ja_node_recompact_add(struct cds_ja *ja,
unsigned int old_type_index,
const struct cds_ja_type *old_type,
struct cds_ja_inode *old_node,
- struct cds_ja_shadow_node **shadow_node,
+ struct cds_ja_shadow_node *shadow_node,
struct cds_ja_inode_flag **old_node_flag, uint8_t n,
struct cds_ja_inode_flag *child_node_flag)
{
unsigned int new_type_index;
struct cds_ja_inode *new_node;
+ struct cds_ja_shadow_node *new_shadow_node;
const struct cds_ja_type *new_type;
struct cds_ja_inode_flag *new_node_flag;
int ret;
+ int fallback = 0;
- if (*shadow_node == NULL) {
+ if (!shadow_node || old_type_index == NODE_INDEX_NULL) {
new_type_index = 0;
} else {
new_type_index = old_type_index + 1;
}
+
+retry: /* for fallback */
+ dbg_printf("Recompact to type %d\n", new_type_index);
new_type = &ja_types[new_type_index];
new_node = alloc_cds_ja_node(new_type);
if (!new_node)
return -ENOMEM;
new_node_flag = ja_node_flag(new_node, new_type_index);
- ret = rcuja_shadow_set(ja->ht, new_node, *shadow_node);
- if (ret)
- return ret;
-
- if (*shadow_node == NULL) {
- *shadow_node = rcuja_shadow_lookup_lock(ja->ht, new_node);
- assert(*shadow_node);
+ dbg_printf("Recompact inherit lock from %p\n", shadow_node);
+ new_shadow_node = rcuja_shadow_set(ja->ht, new_node, shadow_node);
+ if (!new_shadow_node) {
+ free(new_node);
+ return -ENOMEM;
}
-
- /*
- * We need to clear nr_child, because it will be re-incremented
- * by _ja_node_set_nth().
- */
- (*shadow_node)->nr_child = 0;
+ if (fallback)
+ new_shadow_node->fallback_removal_count =
+ JA_FALLBACK_REMOVAL_COUNT;
assert(old_type->type_class != RCU_JA_PIGEON);
switch (old_type->type_class) {
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,
+ ret = _ja_node_set_nth(new_type, new_node,
+ new_shadow_node,
v, iter);
+ if (new_type->type_class == RCU_JA_POOL && ret) {
+ goto fallback_toosmall;
+ }
assert(!ret);
}
break;
j, &v, &iter);
if (!iter)
continue;
- ret = _ja_node_set_nth(new_type, new_node, *shadow_node,
+ ret = _ja_node_set_nth(new_type, new_node,
+ new_shadow_node,
v, iter);
+ if (new_type->type_class == RCU_JA_POOL
+ && ret) {
+ goto fallback_toosmall;
+ }
assert(!ret);
}
}
break;
}
+ case RCU_JA_NULL:
+ /* Nothing to copy */
+ break;
case RCU_JA_PIGEON:
default:
assert(0);
- return -EINVAL;
+ ret = -EINVAL;
+ goto end;
}
/* add node */
- ret = _ja_node_set_nth(new_type, new_node, *shadow_node,
+ ret = _ja_node_set_nth(new_type, new_node,
+ new_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,
+ /* Return pointer to new recompacted new through old_node_flag */
+ *old_node_flag = new_node_flag;
+ if (old_node) {
+ ret = rcuja_shadow_clear(ja->ht, old_node, shadow_node,
+ RCUJA_SHADOW_CLEAR_FREE_NODE);
+ assert(!ret);
+ }
+
+ ret = 0;
+end:
+ return ret;
+
+fallback_toosmall:
+ /* fallback if next pool is too small */
+ ret = rcuja_shadow_clear(ja->ht, new_node, new_shadow_node,
RCUJA_SHADOW_CLEAR_FREE_NODE);
assert(!ret);
- return 0;
+
+ /* Last type: pigeon */
+ new_type_index = (1UL << JA_TYPE_BITS) - 1;
+ dbg_printf("Fallback to type %d\n", new_type_index);
+ uatomic_inc(&ja->nr_fallback);
+ fallback = 1;
+ goto retry;
}
+/*
+ * Return 0 on success, -ENOENT if need to retry, or other negative
+ * error value otherwise.
+ */
static
int ja_node_set_nth(struct cds_ja *ja,
struct cds_ja_inode_flag **node_flag, uint8_t n,
- struct cds_ja_inode_flag *child_node_flag)
+ struct cds_ja_inode_flag *child_node_flag,
+ struct cds_ja_shadow_node *shadow_node)
{
int ret;
unsigned int type_index;
const struct cds_ja_type *type;
struct cds_ja_inode *node;
- struct cds_ja_shadow_node *shadow_node = NULL;
+
+ dbg_printf("ja_node_set_nth for n=%u, node %p, shadow %p\n",
+ (unsigned int) n, ja_node_ptr(*node_flag), shadow_node);
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(ja, type_index, type, node,
- &shadow_node, node_flag, n, child_node_flag);
- /* recompact always leave shadow_node locked */
+ shadow_node, node_flag, n, child_node_flag);
}
- rcuja_shadow_unlock(shadow_node);
return ret;
}
-struct cds_ja_node *cds_ja_lookup(struct cds_ja *ja, uint64_t key)
+struct cds_hlist_head *cds_ja_lookup(struct cds_ja *ja, uint64_t key)
{
unsigned int tree_depth, i;
struct cds_ja_inode_flag *node_flag;
if (caa_unlikely(key > ja->key_max))
return NULL;
tree_depth = ja->tree_depth;
- node_flag = ja->root;
+ node_flag = rcu_dereference(ja->root);
- for (i = 0; i < tree_depth; i++) {
- node_flag = ja_node_get_nth(node_flag,
+ /* level 0: root node */
+ if (!ja_node_ptr(node_flag))
+ return NULL;
+
+ for (i = 1; i < tree_depth; i++) {
+ node_flag = ja_node_get_nth(node_flag, NULL,
(unsigned char) key);
if (!ja_node_ptr(node_flag))
return NULL;
key >>= JA_BITS_PER_BYTE;
}
- /* Last level lookup succeded. We got an actual node. */
- return (struct cds_ja_node *) node_flag;
+ /* Last level lookup succeded. We got an actual match. */
+ return (struct cds_hlist_head *) node_flag;
+}
+
+/*
+ * We reached an unpopulated node. Create it and the children we need,
+ * and then attach the entire branch to the current node. This may
+ * trigger recompaction of the current node. Locks needed: node lock
+ * (for add), and, possibly, parent node lock (to update pointer due to
+ * node recompaction).
+ *
+ * First take node lock, check if recompaction is needed, then take
+ * parent lock (if needed). Then we can proceed to create the new
+ * branch. Publish the new branch, and release locks.
+ * TODO: we currently always take the parent lock even when not needed.
+ */
+static
+int ja_attach_node(struct cds_ja *ja,
+ struct cds_ja_inode_flag **node_flag_ptr,
+ struct cds_ja_inode_flag *node_flag,
+ struct cds_ja_inode_flag *parent_node_flag,
+ uint64_t key,
+ unsigned int depth,
+ struct cds_ja_node *child_node)
+{
+ struct cds_ja_shadow_node *shadow_node = NULL,
+ *parent_shadow_node = NULL,
+ *iter_shadow_node;
+ struct cds_ja_inode *node = ja_node_ptr(node_flag);
+ struct cds_ja_inode *parent_node = ja_node_ptr(parent_node_flag);
+ struct cds_hlist_head head;
+ struct cds_ja_inode_flag *iter_node_flag, *iter_dest_node_flag;
+ int ret, i;
+ struct cds_ja_inode_flag *created_nodes[JA_MAX_DEPTH];
+ int nr_created_nodes = 0;
+
+ dbg_printf("Attach node at depth %u\n", depth);
+
+ assert(node);
+ shadow_node = rcuja_shadow_lookup_lock(ja->ht, node);
+ if (!shadow_node) {
+ ret = -ENOENT;
+ goto end;
+ }
+ if (parent_node) {
+ parent_shadow_node = rcuja_shadow_lookup_lock(ja->ht,
+ parent_node);
+ if (!parent_shadow_node) {
+ ret = -ENOENT;
+ goto unlock_shadow;
+ }
+ }
+
+ /* Create new branch, starting from bottom */
+ CDS_INIT_HLIST_HEAD(&head);
+ cds_hlist_add_head_rcu(&child_node->list, &head);
+ iter_node_flag = (struct cds_ja_inode_flag *) head.next;
+
+ /* Create shadow node for the leaf node */
+ dbg_printf("leaf shadow node creation\n");
+ iter_shadow_node = rcuja_shadow_set(ja->ht,
+ ja_node_ptr(iter_node_flag), NULL);
+ if (!iter_shadow_node) {
+ ret = -ENOMEM;
+ goto check_error;
+ }
+ created_nodes[nr_created_nodes++] = iter_node_flag;
+
+ for (i = ja->tree_depth - 1; i >= (int) depth; i--) {
+ dbg_printf("branch creation level %d, key %" PRIu64 "\n",
+ i, key >> (JA_BITS_PER_BYTE * (i - 2)));
+ iter_dest_node_flag = NULL;
+ ret = ja_node_set_nth(ja, &iter_dest_node_flag,
+ key >> (JA_BITS_PER_BYTE * (i - 2)),
+ iter_node_flag,
+ NULL);
+ if (ret)
+ goto check_error;
+ created_nodes[nr_created_nodes++] = iter_dest_node_flag;
+ iter_node_flag = iter_dest_node_flag;
+ }
+
+ if (depth > 1) {
+ /* We need to use set_nth on the previous level. */
+ iter_dest_node_flag = node_flag;
+ ret = ja_node_set_nth(ja, &iter_dest_node_flag,
+ key >> (JA_BITS_PER_BYTE * (depth - 2)),
+ iter_node_flag,
+ shadow_node);
+ if (ret)
+ goto check_error;
+ created_nodes[nr_created_nodes++] = iter_dest_node_flag;
+ iter_node_flag = iter_dest_node_flag;
+ }
+
+ /* Publish new branch */
+ dbg_printf("Publish branch %p, replacing %p\n",
+ iter_node_flag, *node_flag_ptr);
+ rcu_assign_pointer(*node_flag_ptr, iter_node_flag);
+
+ /* Success */
+ ret = 0;
+
+check_error:
+ if (ret) {
+ for (i = 0; i < nr_created_nodes; i++) {
+ int tmpret;
+ int flags;
+
+ flags = RCUJA_SHADOW_CLEAR_FREE_LOCK;
+ if (i)
+ flags |= RCUJA_SHADOW_CLEAR_FREE_NODE;
+ tmpret = rcuja_shadow_clear(ja->ht,
+ ja_node_ptr(created_nodes[i]),
+ NULL,
+ flags);
+ assert(!tmpret);
+ }
+ }
+ if (parent_shadow_node)
+ rcuja_shadow_unlock(parent_shadow_node);
+unlock_shadow:
+ if (shadow_node)
+ rcuja_shadow_unlock(shadow_node);
+end:
+ return ret;
+}
+
+/*
+ * Lock the hlist head shadow node mutex, and add node to list of
+ * duplicates. Failure can happen if concurrent removal removes the last
+ * node with same key before we get the lock.
+ * Return 0 on success, negative error value on failure.
+ */
+static
+int ja_chain_node(struct cds_ja *ja,
+ struct cds_hlist_head *head,
+ struct cds_ja_node *node)
+{
+ struct cds_ja_shadow_node *shadow_node;
+
+ shadow_node = rcuja_shadow_lookup_lock(ja->ht,
+ (struct cds_ja_inode *) head);
+ if (!shadow_node)
+ return -ENOENT;
+ cds_hlist_add_head_rcu(&node->list, head);
+ rcuja_shadow_unlock(shadow_node);
+ return 0;
+}
+
+int cds_ja_add(struct cds_ja *ja, uint64_t key,
+ struct cds_ja_node *new_node)
+{
+ unsigned int tree_depth, i;
+ uint64_t iter_key;
+ struct cds_ja_inode_flag **node_flag_ptr; /* in parent */
+ struct cds_ja_inode_flag *node_flag,
+ *parent_node_flag,
+ *parent2_node_flag;
+ int ret;
+
+ if (caa_unlikely(key > ja->key_max))
+ return -EINVAL;
+ tree_depth = ja->tree_depth;
+
+retry:
+ dbg_printf("cds_ja_add attempt: key %" PRIu64 ", node %p\n",
+ key, new_node);
+ iter_key = key;
+ parent2_node_flag = NULL;
+ parent_node_flag =
+ (struct cds_ja_inode_flag *) &ja->root; /* Use root ptr address as key for mutex */
+ node_flag_ptr = &ja->root;
+ node_flag = rcu_dereference(*node_flag_ptr);
+
+ /* Iterate on all internal levels */
+ for (i = 1; i < tree_depth; i++) {
+ if (!ja_node_ptr(node_flag)) {
+ ret = ja_attach_node(ja, node_flag_ptr,
+ parent_node_flag, parent2_node_flag,
+ key, i, new_node);
+ if (ret == -ENOENT || ret == -EEXIST)
+ goto retry;
+ else
+ goto end;
+ }
+ parent2_node_flag = parent_node_flag;
+ parent_node_flag = node_flag;
+ node_flag = ja_node_get_nth(node_flag,
+ &node_flag_ptr,
+ (unsigned char) iter_key);
+ iter_key >>= JA_BITS_PER_BYTE;
+ }
+
+ /*
+ * We reached bottom of tree, simply add node to last internal
+ * level, or chain it if key is already present.
+ */
+ if (!ja_node_ptr(node_flag)) {
+ ret = ja_attach_node(ja, node_flag_ptr, parent_node_flag,
+ parent2_node_flag, key, i, new_node);
+ } else {
+ ret = ja_chain_node(ja,
+ (struct cds_hlist_head *) ja_node_ptr(node_flag),
+ new_node);
+ }
+ if (ret == -ENOENT)
+ goto retry;
+end:
+ return ret;
}
struct cds_ja *_cds_ja_new(unsigned int key_bits,
const struct rcu_flavor_struct *flavor)
{
struct cds_ja *ja;
-
+ int ret;
+ struct cds_ja_shadow_node *root_shadow_node;
ja = calloc(sizeof(*ja), 1);
if (!ja)
}
/* ja->root is NULL */
- ja->tree_depth = key_bits >> JA_BITS_PER_BYTE;
+ /* tree_depth 0 is for pointer to root node */
+ ja->tree_depth = (key_bits >> JA_BITS_PER_BYTE) + 1;
+ assert(ja->tree_depth <= JA_MAX_DEPTH);
ja->ht = rcuja_create_ht(flavor);
if (!ja->ht)
goto ht_error;
+
+ /*
+ * Note: we should not free this node until judy array destroy.
+ */
+ root_shadow_node = rcuja_shadow_set(ja->ht,
+ ja_node_ptr((struct cds_ja_inode_flag *) &ja->root),
+ NULL);
+ if (!root_shadow_node) {
+ ret = -ENOMEM;
+ goto ht_node_error;
+ }
+
return ja;
+ht_node_error:
+ ret = rcuja_delete_ht(ja->ht);
+ assert(!ret);
ht_error:
check_error:
free(ja);
ret = rcuja_delete_ht(ja->ht);
if (ret)
return ret;
+ if (uatomic_read(&ja->nr_fallback))
+ fprintf(stderr,
+ "[warning] RCU Judy Array used %lu fallback node(s)\n",
+ uatomic_read(&ja->nr_fallback));
free(ja);
return 0;
}
projects / userspace-rcu.git / blobdiff