* 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/rcuja.h>
#include <urcu/compiler.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 */
/* 32-bit: 101 to 256 children, 1024 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;
- uint16_t min_child; /* minimum number of children: 1 to 256 */
- uint16_t max_child; /* maximum number of children: 1 to 256 */
- uint16_t order; /* node size is (1 << order), in bytes */
+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 order; /* node size is (1 << order), in bytes */
uint16_t nr_pool_order; /* number of pools */
uint16_t pool_size_order; /* pool size */
};
* 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
* The node the index within the following arrays is represented on 3
* bits. It identifies the node type, min/max number of children, and
* the size order.
+ * The max_child values for the RCU_JA_POOL below result from
+ * statistical approximation: over million populations, the max_child
+ * covers between 97% and 99% of the populations generated. Therefore, a
+ * fallback should exist to cover the rare extreme population unbalance
+ * cases, but it will not have a major impact on speed nor space
+ * consumption, since those are rare cases.
*/
#if (CAA_BITS_PER_LONG < 64)
/* 32-bit pointers */
-const struct rcu_ja_type ja_types[] = {
- { .type_class = RCU_JA_LINEAR, .min_child = 1, .max_child = 1, .order = 3, },
- { .type_class = RCU_JA_LINEAR, .min_child = 1, .max_child = 3, .order = 4, },
- { .type_class = RCU_JA_LINEAR, .min_child = 3, .max_child = 6, .order = 5, },
- { .type_class = RCU_JA_LINEAR, .min_child = 4, .max_child = 12, .order = 6, },
- { .type_class = RCU_JA_LINEAR, .min_child = 10, .max_child = 25, .order = 7, },
+enum {
+ ja_type_0_max_child = 1,
+ ja_type_1_max_child = 3,
+ ja_type_2_max_child = 6,
+ ja_type_3_max_child = 12,
+ ja_type_4_max_child = 25,
+ 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_0_max_linear_child = 1,
+ ja_type_1_max_linear_child = 3,
+ ja_type_2_max_linear_child = 6,
+ ja_type_3_max_linear_child = 12,
+ ja_type_4_max_linear_child = 25,
+ ja_type_5_max_linear_child = 24,
+ ja_type_6_max_linear_child = 23,
+};
+
+enum {
+ ja_type_5_nr_pool_order = 1,
+ ja_type_6_nr_pool_order = 2,
+};
+
+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, },
+ { .type_class = RCU_JA_LINEAR, .min_child = 4, .max_child = ja_type_3_max_child, .max_linear_child = ja_type_3_max_linear_child, .order = 6, },
+ { .type_class = RCU_JA_LINEAR, .min_child = 10, .max_child = ja_type_4_max_child, .max_linear_child = ja_type_4_max_linear_child, .order = 7, },
/* Pools may fill sooner than max_child */
- { .type_class = RCU_JA_POOL, .min_child = 20, .max_child = 50, .order = 8, .nr_pool_order = 1, .pool_size_order = 7, },
- { .type_class = RCU_JA_POOL, .min_child = 42, .max_child = 100, .order = 9, .nr_pool_order = 2, .pool_size_order = 7, },
+ { .type_class = RCU_JA_POOL, .min_child = 20, .max_child = ja_type_5_max_child, .max_linear_child = ja_type_5_max_linear_child, .order = 8, .nr_pool_order = ja_type_5_nr_pool_order, .pool_size_order = 7, },
+ { .type_class = RCU_JA_POOL, .min_child = 45, .max_child = ja_type_6_max_child, .max_linear_child = ja_type_6_max_linear_child, .order = 9, .nr_pool_order = ja_type_6_nr_pool_order, .pool_size_order = 7, },
- /* TODO: Upon downsize, if at least one pool is filled, we need to keep pigeon */
- { .type_class = RCU_JA_PIGEON, .min_child = 90, .max_child = 256, .order = 10, },
+ /*
+ * TODO: Upon node removal below min_child, if child pool is
+ * 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, },
};
-CAA_BUILD_BUG_ON(CAA_ARRAY_SIZE(ja_types) > JA_TYPE_MAX_NR);
#else /* !(CAA_BITS_PER_LONG < 64) */
/* 64-bit pointers */
-const struct rcu_ja_type ja_types[] = {
- { .type_class = RCU_JA_LINEAR, .min_child = 1, .max_child = 1, .order = 4, },
- { .type_class = RCU_JA_LINEAR, .min_child = 1, .max_child = 3, .order = 5, },
- { .type_class = RCU_JA_LINEAR, .min_child = 3, .max_child = 7, .order = 6, },
- { .type_class = RCU_JA_LINEAR, .min_child = 5, .max_child = 14, .order = 7, },
- { .type_class = RCU_JA_LINEAR, .min_child = 10, .max_child = 28, .order = 8, },
+enum {
+ ja_type_0_max_child = 1,
+ ja_type_1_max_child = 3,
+ ja_type_2_max_child = 7,
+ ja_type_3_max_child = 14,
+ ja_type_4_max_child = 28,
+ ja_type_5_max_child = 54,
+ ja_type_6_max_child = 104,
+ ja_type_7_max_child = 256,
+ ja_type_8_max_child = 256,
+};
- /* Pools may fill sooner than max_child */
- { .type_class = RCU_JA_POOL, .min_child = 22, .max_child = 56, .order = 9, .nr_pool_order = 1, .pool_size_order = 8, },
- { .type_class = RCU_JA_POOL, .min_child = 44, .max_child = 112, .order = 10, .nr_pool_order = 2, .pool_size_order = 8, },
+enum {
+ ja_type_0_max_linear_child = 1,
+ ja_type_1_max_linear_child = 3,
+ ja_type_2_max_linear_child = 7,
+ ja_type_3_max_linear_child = 14,
+ ja_type_4_max_linear_child = 28,
+ ja_type_5_max_linear_child = 27,
+ ja_type_6_max_linear_child = 26,
+};
- /* TODO: Upon downsize, if at least one pool is filled, we need to keep pigeon */
- { .type_class = RCU_JA_PIGEON, .min_child = 100, .max_child = 256, .order = 11, },
+enum {
+ ja_type_5_nr_pool_order = 1,
+ ja_type_6_nr_pool_order = 2,
+};
+
+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, },
+ { .type_class = RCU_JA_LINEAR, .min_child = 5, .max_child = ja_type_3_max_child, .max_linear_child = ja_type_3_max_linear_child, .order = 7, },
+ { .type_class = RCU_JA_LINEAR, .min_child = 10, .max_child = ja_type_4_max_child, .max_linear_child = ja_type_4_max_linear_child, .order = 8, },
+
+ /* Pools may fill sooner than max_child. */
+ { .type_class = RCU_JA_POOL, .min_child = 22, .max_child = ja_type_5_max_child, .max_linear_child = ja_type_5_max_linear_child, .order = 9, .nr_pool_order = ja_type_5_nr_pool_order, .pool_size_order = 8, },
+ { .type_class = RCU_JA_POOL, .min_child = 51, .max_child = ja_type_6_max_child, .max_linear_child = ja_type_6_max_linear_child, .order = 10, .nr_pool_order = ja_type_6_nr_pool_order, .pool_size_order = 8, },
+
+ /*
+ * TODO: Upon node removal below min_child, if child pool is
+ * 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, },
};
-CAA_BUILD_BUG_ON(CAA_ARRAY_SIZE(ja_types) > JA_TYPE_MAX_NR);
#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);
+}
+
/*
- * The rcu_ja_node starts with a byte counting the number of children in
- * the node. Then, the node-specific data is placed.
- * TODO: where should we put the mutex for the node ?
- * -> mutex could be a 0-value node count.
- * TODO: where do we keep nr children for pigeon ?
+ * 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.
+ * The node mutex, if any is needed, protecting concurrent updated of
+ * each node is placed in a separate hash table indexed by node address.
+ * For the pigeon configuration, the number of children is also kept in
+ * a separate hash table, indexed by node address, because it is only
+ * required for updates.
*/
-struct rcu_ja_node {
- char data[];
-};
-/* Never declared. Opaque type used to store flagged node pointers. */
-struct rcu_ja_node_flag;
+#define DECLARE_LINEAR_NODE(index) \
+ struct { \
+ uint8_t nr_child; \
+ uint8_t child_value[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 { \
+ struct { \
+ uint8_t nr_child; \
+ uint8_t child_value[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 cds_ja_inode {
+ union {
+ /* Linear configuration */
+ DECLARE_LINEAR_NODE(0) conf_0;
+ DECLARE_LINEAR_NODE(1) conf_1;
+ DECLARE_LINEAR_NODE(2) conf_2;
+ DECLARE_LINEAR_NODE(3) conf_3;
+ DECLARE_LINEAR_NODE(4) conf_4;
+
+ /* Pool configuration */
+ DECLARE_POOL_NODE(5) conf_5;
+ DECLARE_POOL_NODE(6) conf_6;
+
+ /* Pigeon configuration */
+ struct {
+ struct cds_ja_inode_flag *child[ja_type_7_max_child];
+ } conf_7;
+ /* data aliasing nodes for computed accesses */
+ 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)
+struct cds_ja_inode_flag *ja_node_flag(struct cds_ja_inode *node,
+ unsigned long type)
{
- assert(type < JA_TYPE_NR);
- return (struct rcu_ja_node_flag *) (((unsigned long) node) | type);
+ assert(type < (1UL << JA_TYPE_BITS));
+ return (struct cds_ja_inode_flag *) (((unsigned long) node) | type);
}
static
-unsigned int ja_node_type(struct rcu_ja_node_flag *node)
+struct cds_ja_inode *ja_node_ptr(struct cds_ja_inode_flag *node)
{
- unsigned int type;
-
- type = (unsigned int) ((unsigned long) node & JA_TYPE_MASK);
- assert(type < JA_TYPE_NR);
- return type;
+ return (struct cds_ja_inode *) (((unsigned long) node) & JA_PTR_MASK);
}
static
-struct rcu_ja_node *ja_node_ptr(struct rcu_ja_node_flag *node)
+unsigned long ja_node_type(struct cds_ja_inode_flag *node)
{
- return (struct rcu_ja_node *) (((unsigned long) node) | JA_PTR_MASK);
+ unsigned long type;
+
+ if (ja_node_ptr(node) == NULL) {
+ return NODE_INDEX_NULL;
+ }
+ type = (unsigned int) ((unsigned long) node & JA_TYPE_MASK);
+ assert(type < (1UL << JA_TYPE_BITS));
+ return type;
}
-struct rcu_ja_node *alloc_rcu_ja_node(struct rcu_ja_type *ja_type)
+struct cds_ja_inode *alloc_cds_ja_node(const struct cds_ja_type *ja_type)
{
- return zmalloc(1 << ja_type->node_order);
+ 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);
}
#define JA_FLOOR(v, align) __JA_FLOOR_MASK(v, (typeof(v)) (align) - 1)
static
-char *align_ptr_size(char *ptr)
+uint8_t *align_ptr_size(uint8_t *ptr)
{
- return JA_ALIGN(ptr, sizeof(ptr));
+ return (uint8_t *) JA_ALIGN((unsigned long) ptr, sizeof(void *));
}
static
-struct rcu_ja_node_flag *ja_linear_node_get_nth(const struct rcu_ja_type *type,
- struct rcu_ja_node *node,
- uint8_t n)
+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 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
+ * associated pointers is still NULL, we return NULL too.
+ */
+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;
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->type_class == RCU_JA_LINEAR);
+ assert(type->type_class == RCU_JA_LINEAR || type->type_class == RCU_JA_POOL);
- nr_child = node->data[0];
- cmm_smp_rmb(); /* read nr_child before values */
- assert(!type || nr_child <= type->max_child);
- assert(!type || nr_child >= type->min_child);
+ 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);
- values = &node[1];
+ values = &node->u.data[1];
for (i = 0; i < nr_child; i++) {
- if (values[i] == n)
+ if (CMM_LOAD_SHARED(values[i]) == n)
break;
}
if (i >= nr_child)
return NULL;
- cmm_smp_rmb(); /* read values before pointer */
- pointers = align_ptr_size(&values[nr_child]);
- ptr = pointers[i];
+ 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 rcu_ja_node_flag *ja_pool_node_get_nth(const struct rcu_ja_type *type,
- struct rcu_ja_node *node,
- uint8_t n)
+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,
+ uint8_t n)
{
- struct rcu_ja_node_flag *ptr;
- struct rcu_ja_node *linear;
+ struct cds_ja_inode *linear;
assert(type->type_class == RCU_JA_POOL);
- linear = (struct rcu_ja_node *)
- &node->data[(n >> (CHAR_BIT - type->nr_pool_order)) << type->pool_size_order];
- return ja_linear_node_get_nth(NULL, linear, n);
+ /*
+ * 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, child_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,
- uint8_t n)
+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 ((struct rcu_ja_node_flag *) node->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);
}
-/* ja_node_get_nth: get nth item from a node */
+/*
+ * ja_node_get_nth: get nth item from a node.
+ * node_flag is already rcu_dereference'd.
+ */
static
-struct rcu_ja_node_flag *ja_node_get_nth(struct rcu_ja_node_flag *node_flag,
- uint8_t n)
+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;
- struct rcu_ja_node *node;
- const struct rcu_ja_type *type;
+ struct cds_ja_inode *node;
+ const struct cds_ja_type *type;
- node_flag = rcu_dereference(node_flag);
node = ja_node_ptr(node_flag);
assert(node != NULL);
type_index = ja_node_type(node_flag);
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;
}
/*
- * ja_node_set_nth: set nth item within a node. asserts that it is not
- * there yet.
+ * 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 cds_ja_shadow_node *shadow_node)
+{
+ return shadow_node->nr_child;
+}
+
+static
+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 cds_ja_inode_flag *child_node_flag)
+{
+ uint8_t nr_child;
+ uint8_t *values, *nr_child_ptr;
+ struct cds_ja_inode_flag **pointers;
+ unsigned int i;
+
+ 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);
+
+ values = &node->u.data[1];
+ for (i = 0; i < nr_child; i++) {
+ if (values[i] == n)
+ return -EEXIST;
+ }
+ if (nr_child >= type->max_linear_child) {
+ /* No space left in this node type */
+ return -ENOSPC;
+ }
+ pointers = (struct cds_ja_inode_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);
+ 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 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)
+{
+ 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_set_nth(type, linear, shadow_node,
+ n, child_node_flag);
+}
+
+static
+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 cds_ja_inode_flag *child_node_flag)
+{
+ struct cds_ja_inode_flag **ptr;
+
+ assert(type->type_class == RCU_JA_PIGEON);
+ 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(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)
+{
+ switch (type->type_class) {
+ case RCU_JA_LINEAR:
+ 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, shadow_node, n,
+ child_node_flag);
+ case RCU_JA_PIGEON:
+ 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;
+}
+/*
+ * 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_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 || 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);
+
+ 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;
+ }
+ 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) {
+ 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;
+ 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;
+ 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);
+ ret = -EINVAL;
+ goto end;
+ }
+
+ /* add node */
+ ret = _ja_node_set_nth(new_type, new_node,
+ new_shadow_node,
+ n, child_node_flag);
+ assert(!ret);
+ /* 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);
+
+ /* 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_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);
+ 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);
+ }
+ 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;
+
+ if (caa_unlikely(key > ja->key_max))
+ return NULL;
+ tree_depth = ja->tree_depth;
+ node_flag = rcu_dereference(ja->root);
+
+ /* 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 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)
+ goto ja_error;
+
+ switch (key_bits) {
+ case 8:
+ ja->key_max = UINT8_MAX;
+ break;
+ case 16:
+ ja->key_max = UINT16_MAX;
+ break;
+ case 32:
+ ja->key_max = UINT32_MAX;
+ 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_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);
+ja_error:
+ return NULL;
+}
+
+/*
+ * 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)
+{
+ int ret;
+
+ rcuja_shadow_prune(ja->ht,
+ RCUJA_SHADOW_CLEAR_FREE_NODE | RCUJA_SHADOW_CLEAR_FREE_LOCK);
+ 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