* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
+#define _LGPL_SOURCE
#include <stdint.h>
#include <errno.h>
#include <limits.h>
#include <urcu/arch.h>
#include <assert.h>
#include <urcu-pointer.h>
+#include <urcu/uatomic.h>
+#include <stdint.h>
#include "rcuja-internal.h"
#include "bitfield.h"
-enum rcu_ja_type_class {
+enum cds_ja_type_class {
RCU_JA_LINEAR = 0, /* Type A */
/* 32-bit: 1 to 25 children, 8 to 128 bytes */
/* 64-bit: 1 to 28 children, 16 to 256 bytes */
/* 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 {
- enum rcu_ja_type_class type_class;
+struct cds_ja_type {
+ enum cds_ja_type_class type_class;
uint16_t min_child; /* minimum number of children: 1 to 256 */
uint16_t max_child; /* maximum number of children: 1 to 256 */
uint16_t max_linear_child; /* per-pool max nr. children: 1 to 256 */
uint16_t pool_size_order; /* pool size */
};
-/*
- * Number of least significant pointer bits reserved to represent the
- * child type.
- */
-#define JA_TYPE_BITS 3
-#define JA_TYPE_MAX_NR (1U << 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
-
/*
* 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 {
ja_type_6_nr_pool_order = 2,
};
-const struct rcu_ja_type ja_types[] = {
+const struct cds_ja_type ja_types[] = {
{ .type_class = RCU_JA_LINEAR, .min_child = 1, .max_child = ja_type_0_max_child, .max_linear_child = ja_type_0_max_linear_child, .order = 3, },
{ .type_class = RCU_JA_LINEAR, .min_child = 1, .max_child = ja_type_1_max_child, .max_linear_child = ja_type_1_max_linear_child, .order = 4, },
{ .type_class = RCU_JA_LINEAR, .min_child = 3, .max_child = ja_type_2_max_child, .max_linear_child = ja_type_2_max_linear_child, .order = 5, },
* 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 {
ja_type_6_nr_pool_order = 2,
};
-const struct rcu_ja_type ja_types[] = {
+const struct cds_ja_type ja_types[] = {
{ .type_class = RCU_JA_LINEAR, .min_child = 1, .max_child = ja_type_0_max_child, .max_linear_child = ja_type_0_max_linear_child, .order = 4, },
{ .type_class = RCU_JA_LINEAR, .min_child = 1, .max_child = ja_type_1_max_child, .max_linear_child = ja_type_1_max_linear_child, .order = 5, },
{ .type_class = RCU_JA_LINEAR, .min_child = 3, .max_child = ja_type_2_max_child, .max_linear_child = ja_type_2_max_linear_child, .order = 6, },
* 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);
}
/*
- * The rcu_ja_node contains the compressed node data needed for
+ * The cds_ja_node contains the compressed node data needed for
* read-side. For linear and pool node configurations, it starts with a
* byte counting the number of children in the node. Then, the
* node-specific data is placed.
struct { \
uint8_t nr_child; \
uint8_t child_value[ja_type_## index ##_max_linear_child]; \
- struct rcu_ja_node_flag *child_ptr[ja_type_## index ##_max_linear_child]; \
+ struct cds_ja_inode_flag *child_ptr[ja_type_## index ##_max_linear_child]; \
}
#define DECLARE_POOL_NODE(index) \
struct { \
uint8_t nr_child; \
uint8_t child_value[ja_type_## index ##_max_linear_child]; \
- struct rcu_ja_node_flag *child_ptr[ja_type_## index ##_max_linear_child]; \
+ struct cds_ja_inode_flag *child_ptr[ja_type_## index ##_max_linear_child]; \
} linear[1U << ja_type_## index ##_nr_pool_order]; \
}
-struct rcu_ja_node {
+struct cds_ja_inode {
union {
/* Linear configuration */
DECLARE_LINEAR_NODE(0) conf_0;
/* Pigeon configuration */
struct {
- struct rcu_ja_node_flag *child[ja_type_7_max_child];
+ struct cds_ja_inode_flag *child[ja_type_7_max_child];
} conf_7;
/* data aliasing nodes for computed accesses */
- uint8_t data[sizeof(struct rcu_ja_node_flag *) * ja_type_7_max_child];
+ uint8_t data[sizeof(struct cds_ja_inode_flag *) * ja_type_7_max_child];
} u;
};
-static
-struct rcu_ja_node_flag *ja_node_flag(struct rcu_ja_node *node,
- unsigned int type)
-{
- assert(type < RCU_JA_NR_TYPES);
- return (struct rcu_ja_node_flag *) (((unsigned long) node) | type);
-}
-
-static
-unsigned int ja_node_type(struct rcu_ja_node_flag *node)
-{
- unsigned int type;
-
- 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);
-}
+enum ja_recompact {
+ JA_RECOMPACT,
+ JA_RECOMPACT_ADD,
+ JA_RECOMPACT_DEL,
+};
-struct rcu_ja_node *alloc_rcu_ja_node(const struct rcu_ja_type *ja_type)
+struct cds_ja_inode *alloc_cds_ja_node(const struct cds_ja_type *ja_type)
{
return calloc(1U << ja_type->order, sizeof(char));
}
-void free_rcu_ja_node(struct rcu_ja_node *node)
+void free_cds_ja_node(struct cds_ja_inode *node)
{
free(node);
}
return (uint8_t *) JA_ALIGN((unsigned long) ptr, sizeof(void *));
}
+static
+uint8_t ja_linear_node_get_nr_child(const struct cds_ja_type *type,
+ struct cds_ja_inode *node)
+{
+ assert(type->type_class == RCU_JA_LINEAR || type->type_class == RCU_JA_POOL);
+ return rcu_dereference(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
* associated pointers is still NULL, we return NULL too.
*/
static
-struct rcu_ja_node_flag *ja_linear_node_get_nth(const struct rcu_ja_type *type,
- struct rcu_ja_node *node,
+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,
+ struct cds_ja_inode_flag ***node_flag_ptr,
uint8_t n)
{
uint8_t nr_child;
uint8_t *values;
- struct rcu_ja_node_flag **pointers;
- struct rcu_ja_node_flag *ptr;
+ struct cds_ja_inode_flag **pointers;
+ struct cds_ja_inode_flag *ptr;
unsigned int i;
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);
if (CMM_LOAD_SHARED(values[i]) == n)
break;
}
- if (i >= nr_child)
+ if (i >= nr_child) {
+ if (caa_unlikely(node_flag_ptr))
+ *node_flag_ptr = NULL;
return NULL;
- pointers = (struct rcu_ja_node_flag **) align_ptr_size(&values[type->max_linear_child]);
+ }
+ pointers = (struct cds_ja_inode_flag **) align_ptr_size(&values[type->max_linear_child]);
ptr = rcu_dereference(pointers[i]);
- assert(ja_node_ptr(ptr) != NULL);
+ if (caa_unlikely(child_node_flag_ptr) && ptr)
+ *child_node_flag_ptr = &pointers[i];
+ if (caa_unlikely(node_flag_ptr))
+ *node_flag_ptr = &pointers[i];
return ptr;
}
static
-struct rcu_ja_node_flag *ja_pool_node_get_nth(const struct rcu_ja_type *type,
- struct rcu_ja_node *node,
+void ja_linear_node_get_ith_pos(const struct cds_ja_type *type,
+ struct cds_ja_inode *node,
+ uint8_t i,
+ uint8_t *v,
+ struct cds_ja_inode_flag **iter)
+{
+ uint8_t *values;
+ struct cds_ja_inode_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 cds_ja_inode_flag **) align_ptr_size(&values[type->max_linear_child]);
+ *iter = pointers[i];
+}
+
+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,
+ struct cds_ja_inode_flag ***node_flag_ptr,
uint8_t n)
{
- struct rcu_ja_node *linear;
+ struct cds_ja_inode *linear;
assert(type->type_class == RCU_JA_POOL);
- linear = (struct rcu_ja_node *)
+ /*
+ * TODO: currently, we select the pool by highest bits. We
+ * should support various encodings.
+ */
+ 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,
+ node_flag_ptr, n);
+}
+
+static
+struct cds_ja_inode *ja_pool_node_get_ith_pool(const struct cds_ja_type *type,
+ struct cds_ja_inode *node,
+ uint8_t i)
+{
+ assert(type->type_class == RCU_JA_POOL);
+ return (struct cds_ja_inode *)
+ &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,
+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,
+ struct cds_ja_inode_flag ***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 rcu_ja_node_flag **) node->u.data)[n]);
+ child_node_flag = &((struct cds_ja_inode_flag **) node->u.data)[n];
+ dbg_printf("ja_pigeon_node_get_nth child_node_flag_ptr %p\n",
+ child_node_flag);
+ if (caa_unlikely(child_node_flag_ptr) && *child_node_flag)
+ *child_node_flag_ptr = child_node_flag;
+ if (caa_unlikely(node_flag_ptr))
+ *node_flag_ptr = child_node_flag;
+ return rcu_dereference(*child_node_flag);
+}
+
+static
+struct cds_ja_inode_flag *ja_pigeon_node_get_ith_pos(const struct cds_ja_type *type,
+ struct cds_ja_inode *node,
+ uint8_t i)
+{
+ return ja_pigeon_node_get_nth(type, node, NULL, NULL, i);
}
/*
* node_flag is already rcu_dereference'd.
*/
static
-struct rcu_ja_node_flag *ja_node_get_nth(struct rcu_ja_node_flag *node_flag,
+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,
+ struct cds_ja_inode_flag ***node_flag_ptr,
uint8_t n)
{
unsigned int type_index;
- struct rcu_ja_node *node;
- const struct rcu_ja_type *type;
+ struct cds_ja_inode *node;
+ const struct cds_ja_type *type;
node = ja_node_ptr(node_flag);
assert(node != NULL);
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, 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, 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, node_flag_ptr, n);
default:
assert(0);
return (void *) -1UL;
}
static
-int ja_linear_node_set_nth(const struct rcu_ja_type *type,
- struct rcu_ja_node *node,
+int ja_linear_node_set_nth(const struct cds_ja_type *type,
+ struct cds_ja_inode *node,
+ struct cds_ja_shadow_node *shadow_node,
uint8_t n,
- struct rcu_ja_node_flag *child_node_flag)
+ struct cds_ja_inode_flag *child_node_flag)
{
uint8_t nr_child;
uint8_t *values, *nr_child_ptr;
- struct rcu_ja_node_flag **pointers;
- unsigned int i;
+ struct cds_ja_inode_flag **pointers;
+ unsigned int i, unused = 0;
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];
+ pointers = (struct cds_ja_inode_flag **) align_ptr_size(&values[type->max_linear_child]);
+ /* Check if node value is already populated */
for (i = 0; i < nr_child; i++) {
- if (values[i] == n)
- return -EEXIST;
+ if (values[i] == n) {
+ if (pointers[i])
+ return -EEXIST;
+ else
+ break;
+ } else {
+ if (!pointers[i])
+ unused++;
+ }
}
- if (nr_child >= type->max_linear_child) {
- /* No space left in this node type */
- return -ENOSPC;
+ if (i == nr_child && nr_child >= type->max_linear_child) {
+ if (unused)
+ return -ERANGE; /* recompact node */
+ else
+ return -ENOSPC; /* No space left in this node type */
}
- pointers = (struct rcu_ja_node_flag **) align_ptr_size(&values[type->max_linear_child]);
- assert(pointers[nr_child] == NULL);
- rcu_assign_pointer(pointers[nr_child], 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);
+
+ assert(pointers[i] == NULL);
+ rcu_assign_pointer(pointers[i], child_node_flag);
+ /* If we expanded the nr_child, increment it */
+ if (i == nr_child) {
+ CMM_STORE_SHARED(values[nr_child], n);
+ /* write pointer and value before nr_child */
+ cmm_smp_wmb();
+ 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;
}
static
-int ja_pool_node_set_nth(const struct rcu_ja_type *type,
- struct rcu_ja_node *node,
+int ja_pool_node_set_nth(const struct cds_ja_type *type,
+ struct cds_ja_inode *node,
+ struct cds_ja_shadow_node *shadow_node,
uint8_t n,
- struct rcu_ja_node_flag *child_node_flag)
+ struct cds_ja_inode_flag *child_node_flag)
{
- struct rcu_ja_node *linear;
+ struct cds_ja_inode *linear;
assert(type->type_class == RCU_JA_POOL);
- linear = (struct rcu_ja_node *)
+ 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_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,
+int ja_pigeon_node_set_nth(const struct cds_ja_type *type,
+ struct cds_ja_inode *node,
+ struct cds_ja_shadow_node *shadow_node,
uint8_t n,
- struct rcu_ja_node_flag *child_node_flag)
+ struct cds_ja_inode_flag *child_node_flag)
{
- struct rcu_ja_node_flag **ptr;
+ struct cds_ja_inode_flag **ptr;
assert(type->type_class == RCU_JA_PIGEON);
- ptr = &((struct rcu_ja_node_flag **) node->u.data)[n];
- if (*ptr != NULL)
+ ptr = &((struct cds_ja_inode_flag **) node->u.data)[n];
+ if (*ptr)
return -EEXIST;
rcu_assign_pointer(*ptr, child_node_flag);
+ shadow_node->nr_child++;
return 0;
}
/*
* _ja_node_set_nth: set nth item within a node. Return an error
* (negative error value) if it is already there.
- * TODO: exclusive access on node.
*/
static
-int _ja_node_set_nth(struct rcu_ja_node_flag *node_flag, uint8_t n,
- struct rcu_ja_node_flag *child_node_flag)
+int _ja_node_set_nth(const struct cds_ja_type *type,
+ struct cds_ja_inode *node,
+ struct cds_ja_shadow_node *shadow_node,
+ uint8_t n,
+ struct cds_ja_inode_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;
return 0;
}
+static
+int ja_linear_node_clear_ptr(const struct cds_ja_type *type,
+ struct cds_ja_inode *node,
+ struct cds_ja_shadow_node *shadow_node,
+ struct cds_ja_inode_flag **node_flag_ptr)
+{
+ uint8_t nr_child;
+ uint8_t *nr_child_ptr;
+
+ assert(type->type_class == RCU_JA_LINEAR || type->type_class == RCU_JA_POOL);
+
+ nr_child_ptr = &node->u.data[0];
+ dbg_printf("linear clear ptr: nr_child_ptr %p\n", nr_child_ptr);
+ nr_child = *nr_child_ptr;
+ assert(nr_child <= type->max_linear_child);
+
+ if (shadow_node->fallback_removal_count) {
+ shadow_node->fallback_removal_count--;
+ } else {
+ if (shadow_node->nr_child <= type->min_child) {
+ /* We need to try recompacting the node */
+ return -EFBIG;
+ }
+ }
+ assert(*node_flag_ptr != NULL);
+ rcu_assign_pointer(*node_flag_ptr, NULL);
+ /*
+ * Value and nr_child are never changed (would cause ABA issue).
+ * Instead, we leave the pointer to NULL and recompact the node
+ * once in a while. It is allowed to set a NULL pointer to a new
+ * value without recompaction though.
+ * Only update the shadow node accounting.
+ */
+ shadow_node->nr_child--;
+ dbg_printf("linear clear ptr: %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;
+}
+
+static
+int ja_pool_node_clear_ptr(const struct cds_ja_type *type,
+ struct cds_ja_inode *node,
+ struct cds_ja_shadow_node *shadow_node,
+ struct cds_ja_inode_flag **node_flag_ptr,
+ uint8_t n)
+{
+ struct cds_ja_inode *linear;
+
+ assert(type->type_class == RCU_JA_POOL);
+ 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_clear_ptr(type, linear, shadow_node, node_flag_ptr);
+}
+
+static
+int ja_pigeon_node_clear_ptr(const struct cds_ja_type *type,
+ struct cds_ja_inode *node,
+ struct cds_ja_shadow_node *shadow_node,
+ struct cds_ja_inode_flag **node_flag_ptr)
+{
+ assert(type->type_class == RCU_JA_PIGEON);
+ dbg_printf("ja_pigeon_node_clear_ptr: clearing ptr: %p\n", *node_flag_ptr);
+ rcu_assign_pointer(*node_flag_ptr, NULL);
+ shadow_node->nr_child--;
+ return 0;
+}
+
/*
- * ja_node_recompact_add: recompact a node, adding a new child.
+ * _ja_node_clear_ptr: clear ptr item within a node. Return an error
+ * (negative error value) if it is not found (-ENOENT).
*/
static
-int ja_node_recompact_add(struct rcu_ja_node_flag **old_node_flag, uint8_t n,
- struct rcu_ja_node_flag *child_node_flag)
+int _ja_node_clear_ptr(const struct cds_ja_type *type,
+ struct cds_ja_inode *node,
+ struct cds_ja_shadow_node *shadow_node,
+ struct cds_ja_inode_flag **node_flag_ptr,
+ uint8_t n)
+{
+ switch (type->type_class) {
+ case RCU_JA_LINEAR:
+ return ja_linear_node_clear_ptr(type, node, shadow_node, node_flag_ptr);
+ case RCU_JA_POOL:
+ return ja_pool_node_clear_ptr(type, node, shadow_node, node_flag_ptr, n);
+ case RCU_JA_PIGEON:
+ return ja_pigeon_node_clear_ptr(type, node, shadow_node, node_flag_ptr);
+ case RCU_JA_NULL:
+ return -ENOENT;
+ default:
+ assert(0);
+ return -EINVAL;
+ }
+ return 0;
+}
+
+/*
+ * 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, -EAGAIN if need to retry, or other negative
+ * error value otherwise.
+ */
+static
+int ja_node_recompact(enum ja_recompact mode,
+ 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_inode_flag **old_node_flag_ptr, uint8_t n,
+ struct cds_ja_inode_flag *child_node_flag,
+ struct cds_ja_inode_flag **nullify_node_flag_ptr)
{
- 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;
- struct rcu_ja_node_flag *new_node_flag;
- unsigned int i;
+ unsigned int new_type_index;
+ struct cds_ja_inode *new_node;
+ struct cds_ja_shadow_node *new_shadow_node = NULL;
+ const struct cds_ja_type *new_type;
+ struct cds_ja_inode_flag *new_node_flag, *old_node_flag;
int ret;
+ int fallback = 0;
- old_node = ja_node_ptr(*old_node_flag);
- if (old_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;
+ old_node_flag = *old_node_flag_ptr;
+
+ switch (mode) {
+ case JA_RECOMPACT:
+ new_type_index = old_type_index;
+ break;
+ case JA_RECOMPACT_ADD:
+ if (!shadow_node || old_type_index == NODE_INDEX_NULL) {
+ new_type_index = 0;
+ } else {
+ new_type_index = old_type_index + 1;
+ }
+ break;
+ case JA_RECOMPACT_DEL:
+ if (old_type_index == 0) {
+ new_type_index = NODE_INDEX_NULL;
+ } else {
+ new_type_index = old_type_index - 1;
+ }
+ break;
+ default:
+ assert(0);
}
+
+retry: /* for fallback */
+ dbg_printf("Recompact from type %d to type %d\n",
+ old_type_index, new_type_index);
new_type = &ja_types[new_type_index];
- new_node = alloc_rcu_ja_node(new_type);
- if (!new_node)
- 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;
-
- iter = ja_node_get_nth(*old_node_flag, i);
- if (!iter)
- continue;
- ret = _ja_node_set_nth(new_node_flag, i, iter);
+ if (new_type_index != NODE_INDEX_NULL) {
+ new_node = alloc_cds_ja_node(new_type);
+ if (!new_node)
+ return -ENOMEM;
+ new_node_flag = ja_node_flag(new_node, new_type_index);
+ dbg_printf("Recompact inherit lock from %p\n", shadow_node);
+ new_shadow_node = rcuja_shadow_set(ja->ht, new_node_flag, shadow_node, ja);
+ if (!new_shadow_node) {
+ free(new_node);
+ return -ENOMEM;
+ }
+ if (fallback)
+ new_shadow_node->fallback_removal_count =
+ JA_FALLBACK_REMOVAL_COUNT;
+ } else {
+ new_node = NULL;
+ new_node_flag = NULL;
+ }
+
+ assert(mode != JA_RECOMPACT_ADD || old_type->type_class != RCU_JA_PIGEON);
+
+ if (new_type_index == NODE_INDEX_NULL)
+ goto skip_copy;
+
+ 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 cds_ja_inode_flag *iter;
+ uint8_t v;
+
+ ja_linear_node_get_ith_pos(old_type, old_node, i, &v, &iter);
+ if (!iter)
+ continue;
+ if (mode == JA_RECOMPACT_DEL && *nullify_node_flag_ptr == iter)
+ continue;
+ 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_POOL:
+ {
+ unsigned int pool_nr;
+
+ for (pool_nr = 0; pool_nr < (1U << old_type->nr_pool_order); pool_nr++) {
+ struct cds_ja_inode *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 cds_ja_inode_flag *iter;
+ uint8_t v;
+
+ ja_linear_node_get_ith_pos(old_type, pool,
+ j, &v, &iter);
+ if (!iter)
+ continue;
+ if (mode == JA_RECOMPACT_DEL && *nullify_node_flag_ptr == iter)
+ continue;
+ 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:
+ assert(mode == JA_RECOMPACT_ADD);
+ break;
+ case RCU_JA_PIGEON:
+ {
+ uint8_t nr_child;
+ unsigned int i;
+
+ assert(mode == JA_RECOMPACT_DEL);
+ nr_child = shadow_node->nr_child;
+ for (i = 0; i < nr_child; i++) {
+ struct cds_ja_inode_flag *iter;
+
+ iter = ja_pigeon_node_get_ith_pos(old_type, old_node, i);
+ if (!iter)
+ continue;
+ if (mode == JA_RECOMPACT_DEL && *nullify_node_flag_ptr == iter)
+ continue;
+ ret = _ja_node_set_nth(new_type, new_node,
+ new_shadow_node,
+ i, iter);
+ if (new_type->type_class == RCU_JA_POOL && ret) {
+ goto fallback_toosmall;
+ }
+ assert(!ret);
+ }
+ break;
+ }
+ default:
+ assert(0);
+ ret = -EINVAL;
+ goto end;
+ }
+skip_copy:
+
+ if (mode == JA_RECOMPACT_ADD) {
+ /* add node */
+ ret = _ja_node_set_nth(new_type, new_node,
+ new_shadow_node,
+ n, child_node_flag);
assert(!ret);
}
- /* add node */
- ret = _ja_node_set_nth(new_node_flag, n, child_node_flag);
+ /* Return pointer to new recompacted node through old_node_flag_ptr */
+ *old_node_flag_ptr = new_node_flag;
+ if (old_node) {
+ int flags;
+
+ flags = RCUJA_SHADOW_CLEAR_FREE_NODE;
+ /*
+ * It is OK to free the lock associated with a node
+ * going to NULL, since we are holding the parent lock.
+ * This synchronizes removal with re-add of that node.
+ */
+ if (new_type_index == NODE_INDEX_NULL)
+ flags = RCUJA_SHADOW_CLEAR_FREE_LOCK;
+ ret = rcuja_shadow_clear(ja->ht, old_node_flag, shadow_node,
+ flags);
+ assert(!ret);
+ }
+
+ ret = 0;
+end:
+ return ret;
+
+fallback_toosmall:
+ /* fallback if next pool is too small */
+ assert(new_shadow_node);
+ ret = rcuja_shadow_clear(ja->ht, new_node_flag, new_shadow_node,
+ RCUJA_SHADOW_CLEAR_FREE_NODE);
assert(!ret);
- /* Replace the old node with the new recompacted one */
- rcu_assign_pointer(*old_node_flag, new_node_flag);
- /* TODO: free old_node (call_rcu) */
+
+ /* Choose fallback 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, -EAGAIN 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_shadow_node *shadow_node)
+{
+ int ret;
+ unsigned int type_index;
+ const struct cds_ja_type *type;
+ struct cds_ja_inode *node;
+
+ 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];
+ ret = _ja_node_set_nth(type, node, shadow_node,
+ n, child_node_flag);
+ switch (ret) {
+ case -ENOSPC:
+ /* Not enough space in node, need to recompact. */
+ ret = ja_node_recompact(JA_RECOMPACT_ADD, ja, type_index, type, node,
+ shadow_node, node_flag, n, child_node_flag, NULL);
+ break;
+ case -ERANGE:
+ /* Node needs to be recompacted. */
+ ret = ja_node_recompact(JA_RECOMPACT, ja, type_index, type, node,
+ shadow_node, node_flag, n, child_node_flag, NULL);
+ break;
+ }
+ return ret;
+}
+
+/*
+ * Return 0 on success, -EAGAIN if need to retry, or other negative
+ * error value otherwise.
+ */
+static
+int ja_node_clear_ptr(struct cds_ja *ja,
+ struct cds_ja_inode_flag **node_flag_ptr, /* Pointer to location to nullify */
+ struct cds_ja_inode_flag **parent_node_flag_ptr, /* Address of parent ptr in its parent */
+ struct cds_ja_shadow_node *shadow_node, /* of parent */
+ uint8_t n)
+{
+ int ret;
+ unsigned int type_index;
+ const struct cds_ja_type *type;
+ struct cds_ja_inode *node;
+
+ dbg_printf("ja_node_clear_ptr for node %p, shadow %p, target ptr %p\n",
+ ja_node_ptr(*parent_node_flag_ptr), shadow_node, node_flag_ptr);
+
+ node = ja_node_ptr(*parent_node_flag_ptr);
+ type_index = ja_node_type(*parent_node_flag_ptr);
+ type = &ja_types[type_index];
+ ret = _ja_node_clear_ptr(type, node, shadow_node, node_flag_ptr, n);
+ if (ret == -EFBIG) {
+ /* Should to try recompaction. */
+ ret = ja_node_recompact(JA_RECOMPACT_DEL, ja, type_index, type, node,
+ shadow_node, parent_node_flag_ptr, n, NULL,
+ node_flag_ptr);
+ }
+ return ret;
+}
+
+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;
+ struct cds_hlist_head head = { NULL };
+
+ if (caa_unlikely(key > ja->key_max))
+ return head;
+ tree_depth = ja->tree_depth;
+ node_flag = rcu_dereference(ja->root);
+
+ /* level 0: root node */
+ if (!ja_node_ptr(node_flag))
+ return head;
+
+ for (i = 1; i < tree_depth; i++) {
+ uint8_t iter_key;
+
+ iter_key = (uint8_t) (key >> (JA_BITS_PER_BYTE * (tree_depth - i - 1)));
+ node_flag = ja_node_get_nth(node_flag, NULL, NULL,
+ iter_key);
+ dbg_printf("cds_ja_lookup iter key lookup %u finds node_flag %p\n",
+ (unsigned int) iter_key, node_flag);
+ if (!ja_node_ptr(node_flag))
+ return head;
+ }
+
+ /* Last level lookup succeded. We got an actual match. */
+ head.next = (struct cds_hlist_node *) node_flag;
+ return head;
+}
+
+/*
+ * 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 **attach_node_flag_ptr,
+ 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 level,
+ struct cds_ja_node *child_node)
+{
+ struct cds_ja_shadow_node *shadow_node = NULL,
+ *parent_shadow_node = NULL;
+ 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 level %u (node %p, node_flag %p)\n",
+ level, node, node_flag);
+
+ assert(node);
+ shadow_node = rcuja_shadow_lookup_lock(ja->ht, node_flag);
+ if (!shadow_node) {
+ ret = -EAGAIN;
+ goto end;
+ }
+ if (parent_node) {
+ parent_shadow_node = rcuja_shadow_lookup_lock(ja->ht,
+ parent_node_flag);
+ if (!parent_shadow_node) {
+ ret = -EAGAIN;
+ goto unlock_shadow;
+ }
+ }
+
+ if (node_flag_ptr && ja_node_ptr(*node_flag_ptr) != NULL) {
+ /*
+ * Target node is non-NULL: it has been updated between
+ * RCU lookup and lock acquisition. We need to re-try
+ * lookup and attach.
+ */
+ ret = -EAGAIN;
+ goto unlock_parent;
+ }
+
+ /* 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;
+
+ for (i = ja->tree_depth; i > (int) level; i--) {
+ uint8_t iter_key;
+
+ iter_key = (uint8_t) (key >> (JA_BITS_PER_BYTE * (ja->tree_depth - i)));
+ dbg_printf("branch creation level %d, key %u\n",
+ i - 1, (unsigned int) iter_key);
+ iter_dest_node_flag = NULL;
+ ret = ja_node_set_nth(ja, &iter_dest_node_flag,
+ iter_key,
+ 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 (level > 1) {
+ uint8_t iter_key;
+
+ iter_key = (uint8_t) (key >> (JA_BITS_PER_BYTE * (ja->tree_depth - level)));
+ /* 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,
+ iter_key,
+ 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, *attach_node_flag_ptr);
+ rcu_assign_pointer(*attach_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,
+ created_nodes[i],
+ NULL,
+ flags);
+ assert(!tmpret);
+ }
+ }
+unlock_parent:
+ 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 parent containing the hlist head pointer, and add node to list of
+ * duplicates. Failure can happen if concurrent update changes the
+ * parent before we get the lock. We return -EAGAIN in that case.
+ * Return 0 on success, negative error value on failure.
+ */
+static
+int ja_chain_node(struct cds_ja *ja,
+ struct cds_ja_inode_flag *parent_node_flag,
+ 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, parent_node_flag);
+ if (!shadow_node) {
+ return -EAGAIN;
+ }
+ 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;
+ struct cds_ja_inode_flag **attach_node_flag_ptr,
+ **node_flag_ptr;
+ 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);
+ parent2_node_flag = NULL;
+ parent_node_flag =
+ (struct cds_ja_inode_flag *) &ja->root; /* Use root ptr address as key for mutex */
+ attach_node_flag_ptr = &ja->root;
+ node_flag_ptr = &ja->root;
+ node_flag = rcu_dereference(ja->root);
+
+ /* Iterate on all internal levels */
+ for (i = 1; i < tree_depth; i++) {
+ uint8_t iter_key;
+
+ dbg_printf("cds_ja_add iter attach_node_flag_ptr %p node_flag_ptr %p node_flag %p\n",
+ *attach_node_flag_ptr, *node_flag_ptr, node_flag);
+ if (!ja_node_ptr(node_flag)) {
+ ret = ja_attach_node(ja, attach_node_flag_ptr,
+ node_flag_ptr,
+ parent_node_flag, parent2_node_flag,
+ key, i, new_node);
+ if (ret == -EAGAIN || ret == -EEXIST)
+ goto retry;
+ else
+ goto end;
+ }
+ iter_key = (uint8_t) (key >> (JA_BITS_PER_BYTE * (tree_depth - i - 1)));
+ parent2_node_flag = parent_node_flag;
+ parent_node_flag = node_flag;
+ node_flag = ja_node_get_nth(node_flag,
+ &attach_node_flag_ptr,
+ &node_flag_ptr,
+ iter_key);
+ dbg_printf("cds_ja_add iter key lookup %u finds node_flag %p attach_node_flag_ptr %p node_flag_ptr %p\n",
+ (unsigned int) iter_key, node_flag,
+ *attach_node_flag_ptr,
+ *node_flag_ptr);
+ }
+
+ /*
+ * 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)) {
+ dbg_printf("cds_ja_add last attach_node_flag_ptr %p node_flag_ptr %p node_flag %p\n",
+ *attach_node_flag_ptr, *node_flag_ptr, node_flag);
+ ret = ja_attach_node(ja, attach_node_flag_ptr,
+ node_flag_ptr, parent_node_flag,
+ parent2_node_flag, key, i, new_node);
+ } else {
+ ret = ja_chain_node(ja,
+ parent_node_flag,
+ (struct cds_hlist_head *) attach_node_flag_ptr,
+ new_node);
+ }
+ if (ret == -EAGAIN || ret == -EEXIST)
+ goto retry;
+end:
+ return ret;
+}
+
+/*
+ * Note: there is no need to lookup the pointer address associated with
+ * each node's nth item after taking the lock: it's already been done by
+ * cds_ja_del while holding the rcu read-side lock, and our node rules
+ * ensure that when a match value -> pointer is found in a node, it is
+ * _NEVER_ changed for that node without recompaction, and recompaction
+ * reallocates the node.
+ * However, when a child is removed from "linear" nodes, its pointer
+ * is set to NULL. We therefore check, while holding the locks, if this
+ * pointer is NULL, and return -ENOENT to the caller if it is the case.
+ */
+static
+int ja_detach_node(struct cds_ja *ja,
+ struct cds_ja_inode_flag **snapshot,
+ struct cds_ja_inode_flag ***snapshot_ptr,
+ uint8_t *snapshot_n,
+ int nr_snapshot,
+ uint64_t key,
+ struct cds_ja_node *node)
+{
+ struct cds_ja_shadow_node *shadow_nodes[JA_MAX_DEPTH];
+ struct cds_ja_inode_flag **node_flag_ptr = NULL,
+ *parent_node_flag = NULL,
+ **parent_node_flag_ptr = NULL;
+ struct cds_ja_inode_flag *iter_node_flag;
+ int ret, i, nr_shadow = 0, nr_clear = 0, nr_branch = 0;
+ uint8_t n = 0;
+
+ assert(nr_snapshot == ja->tree_depth + 1);
+
+ /*
+ * From the last internal level node going up, get the node
+ * lock, check if the node has only one child left. If it is the
+ * case, we continue iterating upward. When we reach a node
+ * which has more that one child left, we lock the parent, and
+ * proceed to the node deletion (removing its children too).
+ */
+ for (i = nr_snapshot - 2; i >= 1; i--) {
+ struct cds_ja_shadow_node *shadow_node;
+
+ shadow_node = rcuja_shadow_lookup_lock(ja->ht,
+ snapshot[i]);
+ if (!shadow_node) {
+ ret = -EAGAIN;
+ goto end;
+ }
+ assert(shadow_node->nr_child > 0);
+ shadow_nodes[nr_shadow++] = shadow_node;
+ if (shadow_node->nr_child == 1 && i > 1)
+ nr_clear++;
+ nr_branch++;
+ if (shadow_node->nr_child > 1 || i == 1) {
+ /* Lock parent and break */
+ shadow_node = rcuja_shadow_lookup_lock(ja->ht,
+ snapshot[i - 1]);
+ if (!shadow_node) {
+ ret = -EAGAIN;
+ goto end;
+ }
+ shadow_nodes[nr_shadow++] = shadow_node;
+ node_flag_ptr = snapshot_ptr[i + 1];
+ n = snapshot_n[i + 1];
+ parent_node_flag_ptr = snapshot_ptr[i];
+ parent_node_flag = snapshot[i];
+ if (i > 1) {
+ /*
+ * Lock parent's parent, in case we need
+ * to recompact parent.
+ */
+ shadow_node = rcuja_shadow_lookup_lock(ja->ht,
+ snapshot[i - 2]);
+ if (!shadow_node) {
+ ret = -EAGAIN;
+ goto end;
+ }
+ shadow_nodes[nr_shadow++] = shadow_node;
+ }
+ break;
+ }
+ }
+
+ /*
+ * Check if node has been removed between RCU lookup and lock
+ * acquisition.
+ */
+ assert(node_flag_ptr);
+ if (ja_node_ptr(*node_flag_ptr) == NULL) {
+ ret = -ENOENT;
+ goto end;
+ }
+
+ /*
+ * At this point, we want to delete all nodes that are about to
+ * be removed from shadow_nodes (except the last one, which is
+ * either the root or the parent of the upmost node with 1
+ * child). OK to as to free lock here, because RCU read lock is
+ * held, and free only performed in call_rcu.
+ */
+
+ for (i = 0; i < nr_clear; i++) {
+ ret = rcuja_shadow_clear(ja->ht,
+ shadow_nodes[i]->node_flag,
+ shadow_nodes[i],
+ RCUJA_SHADOW_CLEAR_FREE_NODE
+ | RCUJA_SHADOW_CLEAR_FREE_LOCK);
+ assert(!ret);
+ }
+
+ iter_node_flag = parent_node_flag;
+ /* Remove from parent */
+ ret = ja_node_clear_ptr(ja,
+ node_flag_ptr, /* Pointer to location to nullify */
+ &iter_node_flag, /* Old new parent ptr in its parent */
+ shadow_nodes[nr_branch - 1], /* of parent */
+ n);
+ if (ret)
+ goto end;
+
+ dbg_printf("ja_detach_node: publish %p instead of %p\n",
+ iter_node_flag, *parent_node_flag_ptr);
+ /* Update address of parent ptr in its parent */
+ rcu_assign_pointer(*parent_node_flag_ptr, iter_node_flag);
+
+end:
+ for (i = 0; i < nr_shadow; i++)
+ rcuja_shadow_unlock(shadow_nodes[i]);
+ return ret;
+}
+
static
-int ja_node_set_nth(struct rcu_ja_node_flag **node_flag, uint8_t n,
- struct rcu_ja_node_flag *child_node_flag)
+int ja_unchain_node(struct cds_ja *ja,
+ struct cds_ja_inode_flag *parent_node_flag,
+ struct cds_hlist_head *head,
+ struct cds_ja_node *node)
+{
+ struct cds_ja_shadow_node *shadow_node;
+ struct cds_hlist_node *hlist_node;
+ int ret = 0, count = 0;
+
+ shadow_node = rcuja_shadow_lookup_lock(ja->ht, parent_node_flag);
+ if (!shadow_node)
+ return -EAGAIN;
+ /*
+ * Retry if another thread removed all but one of duplicates
+ * since check (that was performed without lock).
+ */
+ cds_hlist_for_each_rcu(hlist_node, head, list) {
+ count++;
+ }
+
+ if (count == 1) {
+ ret = -EAGAIN;
+ goto end;
+ }
+ cds_hlist_del_rcu(&node->list);
+end:
+ rcuja_shadow_unlock(shadow_node);
+ return ret;
+}
+
+/*
+ * Called with RCU read lock held.
+ */
+int cds_ja_del(struct cds_ja *ja, uint64_t key,
+ struct cds_ja_node *node)
{
+ unsigned int tree_depth, i;
+ struct cds_ja_inode_flag *snapshot[JA_MAX_DEPTH];
+ struct cds_ja_inode_flag **snapshot_ptr[JA_MAX_DEPTH];
+ uint8_t snapshot_n[JA_MAX_DEPTH];
+ struct cds_ja_inode_flag *node_flag;
+ struct cds_ja_inode_flag **prev_node_flag_ptr;
+ int nr_snapshot;
int ret;
- ret = _ja_node_set_nth(*node_flag, 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;
+ if (caa_unlikely(key > ja->key_max))
+ return -EINVAL;
+ tree_depth = ja->tree_depth;
+
+retry:
+ nr_snapshot = 0;
+ dbg_printf("cds_ja_del attempt: key %" PRIu64 ", node %p\n",
+ key, node);
+
+ /* snapshot for level 0 is only for shadow node lookup */
+ snapshot_n[0] = 0;
+ snapshot_n[1] = 0;
+ snapshot_ptr[nr_snapshot] = NULL;
+ snapshot[nr_snapshot++] = (struct cds_ja_inode_flag *) &ja->root;
+ node_flag = rcu_dereference(ja->root);
+ prev_node_flag_ptr = &ja->root;
+
+ /* Iterate on all internal levels */
+ for (i = 1; i < tree_depth; i++) {
+ uint8_t iter_key;
+
+ dbg_printf("cds_ja_del iter node_flag %p\n",
+ node_flag);
+ if (!ja_node_ptr(node_flag)) {
+ return -ENOENT;
+ }
+ iter_key = (uint8_t) (key >> (JA_BITS_PER_BYTE * (tree_depth - i - 1)));
+ snapshot_n[nr_snapshot + 1] = iter_key;
+ snapshot_ptr[nr_snapshot] = prev_node_flag_ptr;
+ snapshot[nr_snapshot++] = node_flag;
+ node_flag = ja_node_get_nth(node_flag,
+ &prev_node_flag_ptr,
+ NULL,
+ iter_key);
+ dbg_printf("cds_ja_del iter key lookup %u finds node_flag %p, prev_node_flag_ptr %p\n",
+ (unsigned int) iter_key, node_flag,
+ prev_node_flag_ptr);
}
+
+ /*
+ * We reached bottom of tree, try to find the node we are trying
+ * to remove. Fail if we cannot find it.
+ */
+ if (!ja_node_ptr(node_flag)) {
+ dbg_printf("cds_ja_del: no node found for key %" PRIu64 "\n",
+ key);
+ return -ENOENT;
+ } else {
+ struct cds_hlist_head hlist_head;
+ struct cds_hlist_node *hlist_node;
+ struct cds_ja_node *entry, *match = NULL;
+ int count = 0;
+
+ hlist_head.next =
+ (struct cds_hlist_node *) ja_node_ptr(node_flag);
+ cds_hlist_for_each_entry_rcu(entry,
+ hlist_node,
+ &hlist_head,
+ list) {
+ dbg_printf("cds_ja_del: compare %p with entry %p\n", node, entry);
+ if (entry == node)
+ match = entry;
+ count++;
+ }
+ if (!match) {
+ dbg_printf("cds_ja_del: no node match for node %p key %" PRIu64 "\n", node, key);
+ return -ENOENT;
+ }
+ assert(count > 0);
+ if (count == 1) {
+ /*
+ * Removing last of duplicates. Last snapshot
+ * does not have a shadow node (external leafs).
+ */
+ snapshot_ptr[nr_snapshot] = prev_node_flag_ptr;
+ snapshot[nr_snapshot++] = node_flag;
+ ret = ja_detach_node(ja, snapshot, snapshot_ptr,
+ snapshot_n, nr_snapshot, key, node);
+ } else {
+ ret = ja_unchain_node(ja, snapshot[nr_snapshot - 1],
+ &hlist_head, match);
+ }
+ }
+ /*
+ * Explanation of -ENOENT handling: caused by concurrent delete
+ * between RCU lookup and actual removal. Need to re-do the
+ * lookup and removal attempt.
+ */
+ if (ret == -EAGAIN || ret == -ENOENT)
+ goto retry;
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)
+ goto ja_error;
+
+ switch (key_bits) {
+ case 8:
+ case 16:
+ case 24:
+ case 32:
+ case 40:
+ case 48:
+ case 56:
+ ja->key_max = (1ULL << key_bits) - 1;
+ break;
+ case 64:
+ ja->key_max = UINT64_MAX;
+ break;
+ default:
+ goto check_error;
+ }
+
+ /* ja->root is NULL */
+ /* tree_depth 0 is for pointer to root node */
+ ja->tree_depth = (key_bits >> JA_LOG2_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,
+ (struct cds_ja_inode_flag *) &ja->root,
+ NULL, ja);
+ if (!root_shadow_node) {
+ ret = -ENOMEM;
+ goto ht_node_error;
+ }
+ root_shadow_node->level = 0;
+
+ return ja;
+
+ht_node_error:
+ ret = rcuja_delete_ht(ja->ht);
+ assert(!ret);
+ht_error:
+check_error:
+ free(ja);
+ja_error:
+ return NULL;
+}
+
+/*
+ * Called from RCU read-side CS.
+ */
+__attribute__((visibility("protected")))
+void rcuja_free_all_children(struct cds_ja_shadow_node *shadow_node,
+ struct cds_ja_inode_flag *node_flag,
+ void (*free_node_cb)(struct rcu_head *head))
+{
+ const struct rcu_flavor_struct *flavor;
+ unsigned int type_index;
+ struct cds_ja_inode *node;
+ const struct cds_ja_type *type;
+
+ flavor = cds_lfht_rcu_flavor(shadow_node->ja->ht);
+ 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:
+ {
+ uint8_t nr_child =
+ ja_linear_node_get_nr_child(type, node);
+ unsigned int i;
+
+ for (i = 0; i < nr_child; i++) {
+ struct cds_ja_inode_flag *iter;
+ struct cds_hlist_head head;
+ struct cds_ja_node *entry;
+ struct cds_hlist_node *pos;
+ uint8_t v;
+
+ ja_linear_node_get_ith_pos(type, node, i, &v, &iter);
+ if (!iter)
+ continue;
+ head.next = (struct cds_hlist_node *) iter;
+ cds_hlist_for_each_entry_rcu(entry, pos, &head, list) {
+ flavor->update_call_rcu(&entry->head, free_node_cb);
+ }
+ }
+ break;
+ }
+ case RCU_JA_POOL:
+ {
+ unsigned int pool_nr;
+
+ for (pool_nr = 0; pool_nr < (1U << type->nr_pool_order); pool_nr++) {
+ struct cds_ja_inode *pool =
+ ja_pool_node_get_ith_pool(type, node, pool_nr);
+ uint8_t nr_child =
+ ja_linear_node_get_nr_child(type, pool);
+ unsigned int j;
+
+ for (j = 0; j < nr_child; j++) {
+ struct cds_ja_inode_flag *iter;
+ struct cds_hlist_head head;
+ struct cds_ja_node *entry;
+ struct cds_hlist_node *pos;
+ uint8_t v;
+
+ ja_linear_node_get_ith_pos(type, node, j, &v, &iter);
+ if (!iter)
+ continue;
+ head.next = (struct cds_hlist_node *) iter;
+ cds_hlist_for_each_entry_rcu(entry, pos, &head, list) {
+ flavor->update_call_rcu(&entry->head, free_node_cb);
+ }
+ }
+ }
+ break;
+ }
+ case RCU_JA_NULL:
+ break;
+ case RCU_JA_PIGEON:
+ {
+ uint8_t nr_child;
+ unsigned int i;
+
+ nr_child = shadow_node->nr_child;
+ for (i = 0; i < nr_child; i++) {
+ struct cds_ja_inode_flag *iter;
+ struct cds_hlist_head head;
+ struct cds_ja_node *entry;
+ struct cds_hlist_node *pos;
+
+ iter = ja_pigeon_node_get_ith_pos(type, node, i);
+ if (!iter)
+ continue;
+ head.next = (struct cds_hlist_node *) iter;
+ cds_hlist_for_each_entry_rcu(entry, pos, &head, list) {
+ flavor->update_call_rcu(&entry->head, free_node_cb);
+ }
+ }
+ break;
+ }
+ default:
+ assert(0);
+ }
+}
+
+/*
+ * There should be no more concurrent add to the judy array while it is
+ * being destroyed (ensured by the caller).
+ */
+int cds_ja_destroy(struct cds_ja *ja,
+ void (*free_node_cb)(struct rcu_head *head))
+{
+ int ret;
+
+ rcuja_shadow_prune(ja->ht,
+ RCUJA_SHADOW_CLEAR_FREE_NODE | RCUJA_SHADOW_CLEAR_FREE_LOCK,
+ free_node_cb);
+ 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;
+}