--- /dev/null
+/*
+ * rcuja/rcuja.c
+ *
+ * Userspace RCU library - RCU Judy Array
+ *
+ * Copyright (C) 2000 - 2002 Hewlett-Packard Company
+ * Copyright 2012-2013 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * 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 <string.h>
+#include <assert.h>
+#include <urcu/rcuja.h>
+#include <urcu/compiler.h>
+#include <urcu/arch.h>
+#include <urcu-pointer.h>
+#include <urcu/uatomic.h>
+
+#include "rcuja-internal.h"
+
+#ifndef abs
+#define abs_int(a) ((int) (a) > 0 ? (int) (a) : -((int) (a)))
+#endif
+
+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 */
+ RCU_JA_POOL = 1, /* Type B */
+ /* 32-bit: 26 to 100 children, 256 to 512 bytes */
+ /* 64-bit: 29 to 112 children, 512 to 1024 bytes */
+ RCU_JA_PIGEON = 2, /* Type C */
+ /* 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 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 */
+};
+
+/*
+ * 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
+ * possible node size, which contains 256 children).
+ * The min_child overlaps with the previous max_child to provide an
+ * hysteresis loop to reallocation for patterns of cyclic add/removal
+ * within the same node.
+ * 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 */
+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 */
+ /* This pool is hardcoded at index 5. See ja_node_ptr(). */
+ { .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, },
+ /* This pool is hardcoded at index 6. See ja_node_ptr(). */
+ { .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, },
+
+ /*
+ * Upon node removal below min_child, if child pool is filled
+ * beyond capacity, we roll back to pigeon.
+ */
+ { .type_class = RCU_JA_PIGEON, .min_child = 83, .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 */
+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,
+};
+
+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,
+};
+
+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. */
+ /* This pool is hardcoded at index 5. See ja_node_ptr(). */
+ { .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, },
+ /* This pool is hardcoded at index 6. See ja_node_ptr(). */
+ { .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, },
+
+ /*
+ * Upon node removal below min_child, if child pool is filled
+ * beyond capacity, we roll back to pigeon.
+ */
+ { .type_class = RCU_JA_PIGEON, .min_child = 95, .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);
+}
+
+/*
+ * 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.
+ */
+
+#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;
+};
+
+enum ja_recompact {
+ JA_RECOMPACT_ADD_SAME,
+ JA_RECOMPACT_ADD_NEXT,
+ JA_RECOMPACT_DEL,
+};
+
+enum ja_lookup_inequality {
+ JA_LOOKUP_BE,
+ JA_LOOKUP_AE,
+};
+
+enum ja_direction {
+ JA_LEFT,
+ JA_RIGHT,
+ JA_LEFTMOST,
+ JA_RIGHTMOST,
+};
+
+static
+struct cds_ja_inode *_ja_node_mask_ptr(struct cds_ja_inode_flag *node)
+{
+ return (struct cds_ja_inode *) (((unsigned long) node) & JA_PTR_MASK);
+}
+
+unsigned long ja_node_type(struct cds_ja_inode_flag *node)
+{
+ unsigned long type;
+
+ if (_ja_node_mask_ptr(node) == NULL) {
+ return NODE_INDEX_NULL;
+ }
+ type = (unsigned int) ((unsigned long) node & JA_TYPE_MASK);
+ assert(type < (1UL << JA_TYPE_BITS));
+ return type;
+}
+
+static
+struct cds_ja_inode *alloc_cds_ja_node(struct cds_ja *ja,
+ const struct cds_ja_type *ja_type)
+{
+ size_t len = 1U << ja_type->order;
+ void *p;
+ int ret;
+
+ ret = posix_memalign(&p, len, len);
+ if (ret || !p) {
+ return NULL;
+ }
+ memset(p, 0, len);
+ if (ja_debug_counters())
+ uatomic_inc(&ja->nr_nodes_allocated);
+ return p;
+}
+
+void free_cds_ja_node(struct cds_ja *ja, struct cds_ja_inode *node)
+{
+ free(node);
+ if (ja_debug_counters() && node)
+ uatomic_inc(&ja->nr_nodes_freed);
+}
+
+#define __JA_ALIGN_MASK(v, mask) (((v) + (mask)) & ~(mask))
+#define JA_ALIGN(v, align) __JA_ALIGN_MASK(v, (typeof(v)) (align) - 1)
+#define __JA_FLOOR_MASK(v, mask) ((v) & ~(mask))
+#define JA_FLOOR(v, align) __JA_FLOOR_MASK(v, (typeof(v)) (align) - 1)
+
+static
+uint8_t *align_ptr_size(uint8_t *ptr)
+{
+ 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 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 ***node_flag_ptr,
+ uint8_t n)
+{
+ uint8_t nr_child;
+ uint8_t *values;
+ 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 = 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->u.data[1];
+ for (i = 0; i < nr_child; i++) {
+ if (CMM_LOAD_SHARED(values[i]) == n)
+ break;
+ }
+ if (i >= nr_child) {
+ if (caa_unlikely(node_flag_ptr))
+ *node_flag_ptr = NULL;
+ return NULL;
+ }
+ pointers = (struct cds_ja_inode_flag **) align_ptr_size(&values[type->max_linear_child]);
+ ptr = rcu_dereference(pointers[i]);
+ if (caa_unlikely(node_flag_ptr))
+ *node_flag_ptr = &pointers[i];
+ return ptr;
+}
+
+static
+struct cds_ja_inode_flag *ja_linear_node_get_direction(const struct cds_ja_type *type,
+ struct cds_ja_inode *node,
+ int n, uint8_t *result_key,
+ enum ja_direction dir)
+{
+ uint8_t nr_child;
+ uint8_t *values;
+ struct cds_ja_inode_flag **pointers;
+ struct cds_ja_inode_flag *ptr, *match_ptr = NULL;
+ unsigned int i;
+ int match_v;
+
+ assert(type->type_class == RCU_JA_LINEAR || type->type_class == RCU_JA_POOL);
+ assert(dir == JA_LEFT || dir == JA_RIGHT);
+
+ if (dir == JA_LEFT) {
+ match_v = -1;
+ } else {
+ match_v = JA_ENTRY_PER_NODE;
+ }
+
+ 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->u.data[1];
+ pointers = (struct cds_ja_inode_flag **) align_ptr_size(&values[type->max_linear_child]);
+ for (i = 0; i < nr_child; i++) {
+ unsigned int v;
+
+ v = CMM_LOAD_SHARED(values[i]);
+ ptr = CMM_LOAD_SHARED(pointers[i]);
+ if (!ptr)
+ continue;
+ if (dir == JA_LEFT) {
+ if ((int) v < n && (int) v > match_v) {
+ match_v = v;
+ match_ptr = ptr;
+ }
+ } else {
+ if ((int) v > n && (int) v < match_v) {
+ match_v = v;
+ match_ptr = ptr;
+ }
+ }
+ }
+
+ if (!match_ptr) {
+ return NULL;
+ }
+ assert(match_v >= 0 && match_v < JA_ENTRY_PER_NODE);
+
+ *result_key = (uint8_t) match_v;
+ return rcu_dereference(match_ptr);
+}
+
+static
+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 *node_flag,
+ struct cds_ja_inode_flag ***node_flag_ptr,
+ uint8_t n)
+{
+ struct cds_ja_inode *linear;
+
+ assert(type->type_class == RCU_JA_POOL);
+
+ switch (type->nr_pool_order) {
+ case 1:
+ {
+ unsigned long bitsel, index;
+
+ bitsel = ja_node_pool_1d_bitsel(node_flag);
+ assert(bitsel < CHAR_BIT);
+ index = ((unsigned long) n >> bitsel) & 0x1;
+ linear = (struct cds_ja_inode *) &node->u.data[index << type->pool_size_order];
+ break;
+ }
+ case 2:
+ {
+ unsigned long bitsel[2], index[2], rindex;
+
+ ja_node_pool_2d_bitsel(node_flag, bitsel);
+ assert(bitsel[0] < CHAR_BIT);
+ assert(bitsel[1] < CHAR_BIT);
+ index[0] = ((unsigned long) n >> bitsel[0]) & 0x1;
+ index[0] <<= 1;
+ index[1] = ((unsigned long) n >> bitsel[1]) & 0x1;
+ rindex = index[0] | index[1];
+ linear = (struct cds_ja_inode *) &node->u.data[rindex << type->pool_size_order];
+ break;
+ }
+ default:
+ linear = NULL;
+ assert(0);
+ }
+ return ja_linear_node_get_nth(type, linear, 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 cds_ja_inode_flag *ja_pool_node_get_direction(const struct cds_ja_type *type,
+ struct cds_ja_inode *node,
+ int n, uint8_t *result_key,
+ enum ja_direction dir)
+{
+ unsigned int pool_nr;
+ int match_v;
+ struct cds_ja_inode_flag *match_node_flag = NULL;
+
+ assert(type->type_class == RCU_JA_POOL);
+ assert(dir == JA_LEFT || dir == JA_RIGHT);
+
+ if (dir == JA_LEFT) {
+ match_v = -1;
+ } else {
+ match_v = JA_ENTRY_PER_NODE;
+ }
+
+ 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;
+ uint8_t v;
+
+ ja_linear_node_get_ith_pos(type, pool,
+ j, &v, &iter);
+ if (!iter)
+ continue;
+ if (dir == JA_LEFT) {
+ if ((int) v < n && (int) v > match_v) {
+ match_v = v;
+ match_node_flag = iter;
+ }
+ } else {
+ if ((int) v > n && (int) v < match_v) {
+ match_v = v;
+ match_node_flag = iter;
+ }
+ }
+ }
+ }
+ if (match_node_flag)
+ *result_key = (uint8_t) match_v;
+ return match_node_flag;
+}
+
+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 ***node_flag_ptr,
+ uint8_t n)
+{
+ struct cds_ja_inode_flag **child_node_flag_ptr;
+ struct cds_ja_inode_flag *child_node_flag;
+
+ assert(type->type_class == RCU_JA_PIGEON);
+ child_node_flag_ptr = &((struct cds_ja_inode_flag **) node->u.data)[n];
+ child_node_flag = rcu_dereference(*child_node_flag_ptr);
+ dbg_printf("ja_pigeon_node_get_nth child_node_flag_ptr %p\n",
+ child_node_flag_ptr);
+ if (caa_unlikely(node_flag_ptr))
+ *node_flag_ptr = child_node_flag_ptr;
+ return child_node_flag;
+}
+
+static
+struct cds_ja_inode_flag *ja_pigeon_node_get_direction(const struct cds_ja_type *type,
+ struct cds_ja_inode *node,
+ int n, uint8_t *result_key,
+ enum ja_direction dir)
+{
+ struct cds_ja_inode_flag **child_node_flag_ptr;
+ struct cds_ja_inode_flag *child_node_flag;
+ int i;
+
+ assert(type->type_class == RCU_JA_PIGEON);
+ assert(dir == JA_LEFT || dir == JA_RIGHT);
+
+ if (dir == JA_LEFT) {
+ /* n - 1 is first value left of n */
+ for (i = n - 1; i >= 0; i--) {
+ child_node_flag_ptr = &((struct cds_ja_inode_flag **) node->u.data)[i];
+ child_node_flag = rcu_dereference(*child_node_flag_ptr);
+ if (child_node_flag) {
+ dbg_printf("ja_pigeon_node_get_left child_node_flag %p\n",
+ child_node_flag);
+ *result_key = (uint8_t) i;
+ return child_node_flag;
+ }
+ }
+ } else {
+ /* n + 1 is first value right of n */
+ for (i = n + 1; i < JA_ENTRY_PER_NODE; i++) {
+ child_node_flag_ptr = &((struct cds_ja_inode_flag **) node->u.data)[i];
+ child_node_flag = rcu_dereference(*child_node_flag_ptr);
+ if (child_node_flag) {
+ dbg_printf("ja_pigeon_node_get_right child_node_flag %p\n",
+ child_node_flag);
+ *result_key = (uint8_t) i;
+ return child_node_flag;
+ }
+ }
+ }
+ return NULL;
+}
+
+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, i);
+}
+
+/*
+ * ja_node_get_nth: get nth item from a node.
+ * node_flag is already rcu_dereference'd.
+ */
+static
+struct cds_ja_inode_flag *ja_node_get_nth(struct cds_ja_inode_flag *node_flag,
+ struct cds_ja_inode_flag ***node_flag_ptr,
+ uint8_t n)
+{
+ unsigned int type_index;
+ struct cds_ja_inode *node;
+ const struct cds_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_get_nth(type, node,
+ node_flag_ptr, n);
+ case RCU_JA_POOL:
+ return ja_pool_node_get_nth(type, node, node_flag,
+ node_flag_ptr, n);
+ case RCU_JA_PIGEON:
+ return ja_pigeon_node_get_nth(type, node,
+ node_flag_ptr, n);
+ default:
+ assert(0);
+ return (void *) -1UL;
+ }
+}
+
+static
+struct cds_ja_inode_flag *ja_node_get_direction(struct cds_ja_inode_flag *node_flag,
+ int n, uint8_t *result_key,
+ enum ja_direction dir)
+{
+ unsigned int type_index;
+ struct cds_ja_inode *node;
+ const struct cds_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_get_direction(type, node, n, result_key, dir);
+ case RCU_JA_POOL:
+ return ja_pool_node_get_direction(type, node, n, result_key, dir);
+ case RCU_JA_PIGEON:
+ return ja_pigeon_node_get_direction(type, node, n, result_key, dir);
+ default:
+ assert(0);
+ return (void *) -1UL;
+ }
+}
+
+static
+struct cds_ja_inode_flag *ja_node_get_leftright(struct cds_ja_inode_flag *node_flag,
+ unsigned int n, uint8_t *result_key,
+ enum ja_direction dir)
+{
+ return ja_node_get_direction(node_flag, n, result_key, dir);
+}
+
+static
+struct cds_ja_inode_flag *ja_node_get_minmax(struct cds_ja_inode_flag *node_flag,
+ uint8_t *result_key,
+ enum ja_direction dir)
+{
+ switch (dir) {
+ case JA_LEFTMOST:
+ return ja_node_get_direction(node_flag,
+ -1, result_key, JA_RIGHT);
+ case JA_RIGHTMOST:
+ return ja_node_get_direction(node_flag,
+ JA_ENTRY_PER_NODE, result_key, JA_LEFT);
+ default:
+ assert(0);
+ }
+}
+
+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, 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: n %u, nr_child_ptr %p\n",
+ (unsigned int) n, nr_child_ptr);
+ nr_child = *nr_child_ptr;
+ assert(nr_child <= type->max_linear_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) {
+ if (pointers[i])
+ return -EEXIST;
+ else
+ break;
+ } else {
+ if (!pointers[i])
+ unused++;
+ }
+ }
+ 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 */
+ }
+
+ 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 cds_ja_type *type,
+ struct cds_ja_inode *node,
+ struct cds_ja_inode_flag *node_flag,
+ 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);
+
+ switch (type->nr_pool_order) {
+ case 1:
+ {
+ unsigned long bitsel, index;
+
+ bitsel = ja_node_pool_1d_bitsel(node_flag);
+ assert(bitsel < CHAR_BIT);
+ index = ((unsigned long) n >> bitsel) & 0x1;
+ linear = (struct cds_ja_inode *) &node->u.data[index << type->pool_size_order];
+ break;
+ }
+ case 2:
+ {
+ unsigned long bitsel[2], index[2], rindex;
+
+ ja_node_pool_2d_bitsel(node_flag, bitsel);
+ assert(bitsel[0] < CHAR_BIT);
+ assert(bitsel[1] < CHAR_BIT);
+ index[0] = ((unsigned long) n >> bitsel[0]) & 0x1;
+ index[0] <<= 1;
+ index[1] = ((unsigned long) n >> bitsel[1]) & 0x1;
+ rindex = index[0] | index[1];
+ linear = (struct cds_ja_inode *) &node->u.data[rindex << type->pool_size_order];
+ break;
+ }
+ default:
+ linear = NULL;
+ assert(0);
+ }
+
+ 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.
+ */
+static
+int _ja_node_set_nth(const struct cds_ja_type *type,
+ struct cds_ja_inode *node,
+ struct cds_ja_inode_flag *node_flag,
+ 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, node_flag, 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;
+}
+
+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];
+ nr_child = *nr_child_ptr;
+ assert(nr_child <= type->max_linear_child);
+
+ if (type->type_class == RCU_JA_LINEAR) {
+ assert(!shadow_node->fallback_removal_count);
+ if (shadow_node->nr_child <= type->min_child) {
+ /* We need to try recompacting the node */
+ return -EFBIG;
+ }
+ }
+ dbg_printf("linear clear ptr: nr_child_ptr %p\n", nr_child_ptr);
+ 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_inode_flag *node_flag,
+ 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);
+
+ if (shadow_node->fallback_removal_count) {
+ shadow_node->fallback_removal_count--;
+ } else {
+ /* We should try recompacting the node */
+ if (shadow_node->nr_child <= type->min_child)
+ return -EFBIG;
+ }
+
+ switch (type->nr_pool_order) {
+ case 1:
+ {
+ unsigned long bitsel, index;
+
+ bitsel = ja_node_pool_1d_bitsel(node_flag);
+ assert(bitsel < CHAR_BIT);
+ index = ((unsigned long) n >> bitsel) & type->nr_pool_order;
+ linear = (struct cds_ja_inode *) &node->u.data[index << type->pool_size_order];
+ break;
+ }
+ case 2:
+ {
+ unsigned long bitsel[2], index[2], rindex;
+
+ ja_node_pool_2d_bitsel(node_flag, bitsel);
+ assert(bitsel[0] < CHAR_BIT);
+ assert(bitsel[1] < CHAR_BIT);
+ index[0] = ((unsigned long) n >> bitsel[0]) & 0x1;
+ index[0] <<= 1;
+ index[1] = ((unsigned long) n >> bitsel[1]) & 0x1;
+ rindex = index[0] | index[1];
+ linear = (struct cds_ja_inode *) &node->u.data[rindex << type->pool_size_order];
+ break;
+ }
+ default:
+ linear = NULL;
+ assert(0);
+ }
+
+ 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);
+
+ if (shadow_node->fallback_removal_count) {
+ shadow_node->fallback_removal_count--;
+ } else {
+ /* We should try recompacting the node */
+ if (shadow_node->nr_child <= type->min_child)
+ return -EFBIG;
+ }
+ 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_clear_ptr: clear ptr item within a node. Return an error
+ * (negative error value) if it is not found (-ENOENT).
+ */
+static
+int _ja_node_clear_ptr(const struct cds_ja_type *type,
+ struct cds_ja_inode *node,
+ struct cds_ja_inode_flag *node_flag,
+ 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, node_flag, 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;
+}
+
+/*
+ * Calculate bit distribution. Returns the bit (0 to 7) that splits the
+ * distribution in two sub-distributions containing as much elements one
+ * compared to the other.
+ */
+static
+unsigned int ja_node_sum_distribution_1d(enum ja_recompact mode,
+ struct cds_ja *ja,
+ unsigned int type_index,
+ 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 **nullify_node_flag_ptr)
+{
+ uint8_t nr_one[JA_BITS_PER_BYTE];
+ unsigned int bitsel = 0, bit_i, overall_best_distance = UINT_MAX;
+ unsigned int distrib_nr_child = 0;
+
+ memset(nr_one, 0, sizeof(nr_one));
+
+ 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;
+ uint8_t v;
+
+ ja_linear_node_get_ith_pos(type, node, i, &v, &iter);
+ if (!iter)
+ continue;
+ if (mode == JA_RECOMPACT_DEL && *nullify_node_flag_ptr == iter)
+ continue;
+ for (bit_i = 0; bit_i < JA_BITS_PER_BYTE; bit_i++) {
+ if (v & (1U << bit_i))
+ nr_one[bit_i]++;
+ }
+ distrib_nr_child++;
+ }
+ 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;
+ uint8_t v;
+
+ ja_linear_node_get_ith_pos(type, pool,
+ j, &v, &iter);
+ if (!iter)
+ continue;
+ if (mode == JA_RECOMPACT_DEL && *nullify_node_flag_ptr == iter)
+ continue;
+ for (bit_i = 0; bit_i < JA_BITS_PER_BYTE; bit_i++) {
+ if (v & (1U << bit_i))
+ nr_one[bit_i]++;
+ }
+ distrib_nr_child++;
+ }
+ }
+ break;
+ }
+ case RCU_JA_PIGEON:
+ {
+ unsigned int i;
+
+ assert(mode == JA_RECOMPACT_DEL);
+ for (i = 0; i < JA_ENTRY_PER_NODE; i++) {
+ struct cds_ja_inode_flag *iter;
+
+ iter = ja_pigeon_node_get_ith_pos(type, node, i);
+ if (!iter)
+ continue;
+ if (mode == JA_RECOMPACT_DEL && *nullify_node_flag_ptr == iter)
+ continue;
+ for (bit_i = 0; bit_i < JA_BITS_PER_BYTE; bit_i++) {
+ if (i & (1U << bit_i))
+ nr_one[bit_i]++;
+ }
+ distrib_nr_child++;
+ }
+ break;
+ }
+ case RCU_JA_NULL:
+ assert(mode == JA_RECOMPACT_ADD_NEXT);
+ break;
+ default:
+ assert(0);
+ break;
+ }
+
+ if (mode == JA_RECOMPACT_ADD_NEXT || mode == JA_RECOMPACT_ADD_SAME) {
+ for (bit_i = 0; bit_i < JA_BITS_PER_BYTE; bit_i++) {
+ if (n & (1U << bit_i))
+ nr_one[bit_i]++;
+ }
+ distrib_nr_child++;
+ }
+
+ /*
+ * The best bit selector is that for which the number of ones is
+ * closest to half of the number of children in the
+ * distribution. We calculate the distance using the double of
+ * the sub-distribution sizes to eliminate truncation error.
+ */
+ for (bit_i = 0; bit_i < JA_BITS_PER_BYTE; bit_i++) {
+ unsigned int distance_to_best;
+
+ distance_to_best = abs_int(((unsigned int) nr_one[bit_i] << 1U) - distrib_nr_child);
+ if (distance_to_best < overall_best_distance) {
+ overall_best_distance = distance_to_best;
+ bitsel = bit_i;
+ }
+ }
+ dbg_printf("1 dimension pool bit selection: (%u)\n", bitsel);
+ return bitsel;
+}
+
+/*
+ * Calculate bit distribution in two dimensions. Returns the two bits
+ * (each 0 to 7) that splits the distribution in four sub-distributions
+ * containing as much elements one compared to the other.
+ */
+static
+void ja_node_sum_distribution_2d(enum ja_recompact mode,
+ struct cds_ja *ja,
+ unsigned int type_index,
+ 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 **nullify_node_flag_ptr,
+ unsigned int *_bitsel)
+{
+ uint8_t nr_2d_11[JA_BITS_PER_BYTE][JA_BITS_PER_BYTE],
+ nr_2d_10[JA_BITS_PER_BYTE][JA_BITS_PER_BYTE],
+ nr_2d_01[JA_BITS_PER_BYTE][JA_BITS_PER_BYTE],
+ nr_2d_00[JA_BITS_PER_BYTE][JA_BITS_PER_BYTE];
+ unsigned int bitsel[2] = { 0, 1 };
+ unsigned int bit_i, bit_j;
+ int overall_best_distance = INT_MAX;
+ unsigned int distrib_nr_child = 0;
+
+ memset(nr_2d_11, 0, sizeof(nr_2d_11));
+ memset(nr_2d_10, 0, sizeof(nr_2d_10));
+ memset(nr_2d_01, 0, sizeof(nr_2d_01));
+ memset(nr_2d_00, 0, sizeof(nr_2d_00));
+
+ 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;
+ uint8_t v;
+
+ ja_linear_node_get_ith_pos(type, node, i, &v, &iter);
+ if (!iter)
+ continue;
+ if (mode == JA_RECOMPACT_DEL && *nullify_node_flag_ptr == iter)
+ continue;
+ for (bit_i = 0; bit_i < JA_BITS_PER_BYTE; bit_i++) {
+ for (bit_j = 0; bit_j < bit_i; bit_j++) {
+ if (v & (1U << bit_i)) {
+ if (v & (1U << bit_j)) {
+ nr_2d_11[bit_i][bit_j]++;
+ } else {
+ nr_2d_10[bit_i][bit_j]++;
+ }
+ } else {
+ if (v & (1U << bit_j)) {
+ nr_2d_01[bit_i][bit_j]++;
+ } else {
+ nr_2d_00[bit_i][bit_j]++;
+ }
+ }
+ }
+ }
+ distrib_nr_child++;
+ }
+ 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;
+ uint8_t v;
+
+ ja_linear_node_get_ith_pos(type, pool,
+ j, &v, &iter);
+ if (!iter)
+ continue;
+ if (mode == JA_RECOMPACT_DEL && *nullify_node_flag_ptr == iter)
+ continue;
+ for (bit_i = 0; bit_i < JA_BITS_PER_BYTE; bit_i++) {
+ for (bit_j = 0; bit_j < bit_i; bit_j++) {
+ if (v & (1U << bit_i)) {
+ if (v & (1U << bit_j)) {
+ nr_2d_11[bit_i][bit_j]++;
+ } else {
+ nr_2d_10[bit_i][bit_j]++;
+ }
+ } else {
+ if (v & (1U << bit_j)) {
+ nr_2d_01[bit_i][bit_j]++;
+ } else {
+ nr_2d_00[bit_i][bit_j]++;
+ }
+ }
+ }
+ }
+ distrib_nr_child++;
+ }
+ }
+ break;
+ }
+ case RCU_JA_PIGEON:
+ {
+ unsigned int i;
+
+ assert(mode == JA_RECOMPACT_DEL);
+ for (i = 0; i < JA_ENTRY_PER_NODE; i++) {
+ struct cds_ja_inode_flag *iter;
+
+ iter = ja_pigeon_node_get_ith_pos(type, node, i);
+ if (!iter)
+ continue;
+ if (mode == JA_RECOMPACT_DEL && *nullify_node_flag_ptr == iter)
+ continue;
+ for (bit_i = 0; bit_i < JA_BITS_PER_BYTE; bit_i++) {
+ for (bit_j = 0; bit_j < bit_i; bit_j++) {
+ if (i & (1U << bit_i)) {
+ if (i & (1U << bit_j)) {
+ nr_2d_11[bit_i][bit_j]++;
+ } else {
+ nr_2d_10[bit_i][bit_j]++;
+ }
+ } else {
+ if (i & (1U << bit_j)) {
+ nr_2d_01[bit_i][bit_j]++;
+ } else {
+ nr_2d_00[bit_i][bit_j]++;
+ }
+ }
+ }
+ }
+ distrib_nr_child++;
+ }
+ break;
+ }
+ case RCU_JA_NULL:
+ assert(mode == JA_RECOMPACT_ADD_NEXT);
+ break;
+ default:
+ assert(0);
+ break;
+ }
+
+ if (mode == JA_RECOMPACT_ADD_NEXT || mode == JA_RECOMPACT_ADD_SAME) {
+ for (bit_i = 0; bit_i < JA_BITS_PER_BYTE; bit_i++) {
+ for (bit_j = 0; bit_j < bit_i; bit_j++) {
+ if (n & (1U << bit_i)) {
+ if (n & (1U << bit_j)) {
+ nr_2d_11[bit_i][bit_j]++;
+ } else {
+ nr_2d_10[bit_i][bit_j]++;
+ }
+ } else {
+ if (n & (1U << bit_j)) {
+ nr_2d_01[bit_i][bit_j]++;
+ } else {
+ nr_2d_00[bit_i][bit_j]++;
+ }
+ }
+ }
+ }
+ distrib_nr_child++;
+ }
+
+ /*
+ * The best bit selector is that for which the number of nodes
+ * in each sub-class is closest to one-fourth of the number of
+ * children in the distribution. We calculate the distance using
+ * 4 times the size of the sub-distribution to eliminate
+ * truncation error.
+ */
+ for (bit_i = 0; bit_i < JA_BITS_PER_BYTE; bit_i++) {
+ for (bit_j = 0; bit_j < bit_i; bit_j++) {
+ int distance_to_best[4];
+
+ distance_to_best[0] = ((unsigned int) nr_2d_11[bit_i][bit_j] << 2U) - distrib_nr_child;
+ distance_to_best[1] = ((unsigned int) nr_2d_10[bit_i][bit_j] << 2U) - distrib_nr_child;
+ distance_to_best[2] = ((unsigned int) nr_2d_01[bit_i][bit_j] << 2U) - distrib_nr_child;
+ distance_to_best[3] = ((unsigned int) nr_2d_00[bit_i][bit_j] << 2U) - distrib_nr_child;
+
+ /* Consider worse distance above best */
+ if (distance_to_best[1] > 0 && distance_to_best[1] > distance_to_best[0])
+ distance_to_best[0] = distance_to_best[1];
+ if (distance_to_best[2] > 0 && distance_to_best[2] > distance_to_best[0])
+ distance_to_best[0] = distance_to_best[2];
+ if (distance_to_best[3] > 0 && distance_to_best[3] > distance_to_best[0])
+ distance_to_best[0] = distance_to_best[3];
+
+ /*
+ * If our worse distance is better than overall,
+ * we become new best candidate.
+ */
+ if (distance_to_best[0] < overall_best_distance) {
+ overall_best_distance = distance_to_best[0];
+ bitsel[0] = bit_i;
+ bitsel[1] = bit_j;
+ }
+ }
+ }
+
+ dbg_printf("2 dimensions pool bit selection: (%u,%u)\n", bitsel[0], bitsel[1]);
+
+ /* Return our bit selection */
+ _bitsel[0] = bitsel[0];
+ _bitsel[1] = bitsel[1];
+}
+
+static
+unsigned int find_nearest_type_index(unsigned int type_index,
+ unsigned int nr_nodes)
+{
+ const struct cds_ja_type *type;
+
+ assert(type_index != NODE_INDEX_NULL);
+ if (nr_nodes == 0)
+ return NODE_INDEX_NULL;
+ for (;;) {
+ type = &ja_types[type_index];
+ if (nr_nodes < type->min_child)
+ type_index--;
+ else if (nr_nodes > type->max_child)
+ type_index++;
+ else
+ break;
+ }
+ return type_index;
+}
+
+/*
+ * ja_node_recompact_add: recompact a node, adding a new child.
+ * 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,
+ int level)
+{
+ 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_flag = *old_node_flag_ptr;
+
+ /*
+ * Need to find nearest type index even for ADD_SAME, because
+ * this recompaction, when applied to linear nodes, will garbage
+ * collect dummy (NULL) entries, and can therefore cause a few
+ * linear representations to be skipped.
+ */
+ switch (mode) {
+ case JA_RECOMPACT_ADD_SAME:
+ new_type_index = find_nearest_type_index(old_type_index,
+ shadow_node->nr_child + 1);
+ dbg_printf("Recompact for node with %u children\n",
+ shadow_node->nr_child + 1);
+ break;
+ case JA_RECOMPACT_ADD_NEXT:
+ if (!shadow_node || old_type_index == NODE_INDEX_NULL) {
+ new_type_index = 0;
+ dbg_printf("Recompact for NULL\n");
+ } else {
+ new_type_index = find_nearest_type_index(old_type_index,
+ shadow_node->nr_child + 1);
+ dbg_printf("Recompact for node with %u children\n",
+ shadow_node->nr_child + 1);
+ }
+ break;
+ case JA_RECOMPACT_DEL:
+ new_type_index = find_nearest_type_index(old_type_index,
+ shadow_node->nr_child - 1);
+ dbg_printf("Recompact for node with %u children\n",
+ shadow_node->nr_child - 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];
+ if (new_type_index != NODE_INDEX_NULL) {
+ new_node = alloc_cds_ja_node(ja, new_type);
+ if (!new_node)
+ return -ENOMEM;
+
+ if (new_type->type_class == RCU_JA_POOL) {
+ switch (new_type->nr_pool_order) {
+ case 1:
+ {
+ unsigned int node_distrib_bitsel;
+
+ node_distrib_bitsel =
+ ja_node_sum_distribution_1d(mode, ja,
+ old_type_index, old_type,
+ old_node, shadow_node,
+ n, child_node_flag,
+ nullify_node_flag_ptr);
+ assert(!((unsigned long) new_node & JA_POOL_1D_MASK));
+ new_node_flag = ja_node_flag_pool_1d(new_node,
+ new_type_index, node_distrib_bitsel);
+ break;
+ }
+ case 2:
+ {
+ unsigned int node_distrib_bitsel[2];
+
+ ja_node_sum_distribution_2d(mode, ja,
+ old_type_index, old_type,
+ old_node, shadow_node,
+ n, child_node_flag,
+ nullify_node_flag_ptr,
+ node_distrib_bitsel);
+ assert(!((unsigned long) new_node & JA_POOL_1D_MASK));
+ assert(!((unsigned long) new_node & JA_POOL_2D_MASK));
+ new_node_flag = ja_node_flag_pool_2d(new_node,
+ new_type_index, node_distrib_bitsel);
+ break;
+ }
+ default:
+ assert(0);
+ }
+ } else {
+ 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, level);
+ if (!new_shadow_node) {
+ free_cds_ja_node(ja, 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_NEXT || 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_node_flag,
+ 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_node_flag,
+ 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_NEXT);
+ break;
+ case RCU_JA_PIGEON:
+ {
+ unsigned int i;
+
+ assert(mode == JA_RECOMPACT_DEL);
+ for (i = 0; i < JA_ENTRY_PER_NODE; 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_node_flag,
+ 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_NEXT || mode == JA_RECOMPACT_ADD_SAME) {
+ /* add node */
+ ret = _ja_node_set_nth(new_type, new_node, new_node_flag,
+ new_shadow_node,
+ n, child_node_flag);
+ if (new_type->type_class == RCU_JA_POOL && ret) {
+ goto fallback_toosmall;
+ }
+ assert(!ret);
+ }
+
+ if (fallback) {
+ dbg_printf("Using fallback for %u children, node type index: %u, mode %s\n",
+ new_shadow_node->nr_child, old_type_index, mode == JA_RECOMPACT_ADD_NEXT ? "add_next" :
+ (mode == JA_RECOMPACT_DEL ? "del" : "add_same"));
+ if (ja_debug_counters())
+ uatomic_inc(&ja->node_fallback_count_distribution[new_shadow_node->nr_child]);
+ }
+
+ /* 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);
+
+ switch (mode) {
+ case JA_RECOMPACT_ADD_SAME:
+ /*
+ * JA_RECOMPACT_ADD_SAME is only triggered if a linear
+ * node within a pool has unused entries. It should
+ * therefore _never_ be too small.
+ */
+ assert(0);
+
+ /* Fall-through */
+ case JA_RECOMPACT_ADD_NEXT:
+ {
+ const struct cds_ja_type *next_type;
+
+ /*
+ * Recompaction attempt on add failed. Should only
+ * happen if target node type is pool. Caused by
+ * hard-to-split distribution. Recompact using the next
+ * distribution size.
+ */
+ assert(new_type->type_class == RCU_JA_POOL);
+ next_type = &ja_types[new_type_index + 1];
+ /*
+ * Try going to the next pool size if our population
+ * fits within its range. This is not flagged as a
+ * fallback.
+ */
+ if (shadow_node->nr_child + 1 >= next_type->min_child
+ && shadow_node->nr_child + 1 <= next_type->max_child) {
+ new_type_index++;
+ goto retry;
+ } else {
+ new_type_index++;
+ dbg_printf("Add fallback to type %d\n", new_type_index);
+ if (ja_debug_counters())
+ uatomic_inc(&ja->nr_fallback);
+ fallback = 1;
+ goto retry;
+ }
+ break;
+ }
+ case JA_RECOMPACT_DEL:
+ /*
+ * Recompaction attempt on delete failed. Should only
+ * happen if target node type is pool. This is caused by
+ * a hard-to-split distribution. Recompact on same node
+ * size, but flag current node as "fallback" to ensure
+ * we don't attempt recompaction before some activity
+ * has reshuffled our node.
+ */
+ assert(new_type->type_class == RCU_JA_POOL);
+ new_type_index = old_type_index;
+ dbg_printf("Delete fallback keeping type %d\n", new_type_index);
+ uatomic_inc(&ja->nr_fallback);
+ fallback = 1;
+ goto retry;
+ default:
+ assert(0);
+ return -EINVAL;
+ }
+
+ /*
+ * Last resort fallback: 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 level)
+{
+ 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, *node_flag, shadow_node,
+ n, child_node_flag);
+ switch (ret) {
+ case -ENOSPC:
+ /* Not enough space in node, need to recompact to next type. */
+ ret = ja_node_recompact(JA_RECOMPACT_ADD_NEXT, ja, type_index, type, node,
+ shadow_node, node_flag, n, child_node_flag, NULL, level);
+ break;
+ case -ERANGE:
+ /* Node needs to be recompacted. */
+ ret = ja_node_recompact(JA_RECOMPACT_ADD_SAME, ja, type_index, type, node,
+ shadow_node, node_flag, n, child_node_flag, NULL, level);
+ 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 level)
+{
+ 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, *parent_node_flag_ptr, shadow_node, node_flag_ptr, n);
+ if (ret == -EFBIG) {
+ /* Should 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, level);
+ }
+ return ret;
+}
+
+struct cds_ja_node *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 || key == UINT64_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++) {
+ 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, 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 NULL;
+ }
+
+ /* Last level lookup succeded. We got an actual match. */
+ return (struct cds_ja_node *) node_flag;
+}
+
+static
+struct cds_ja_node *cds_ja_lookup_inequality(struct cds_ja *ja, uint64_t key,
+ uint64_t *result_key, enum ja_lookup_inequality mode)
+{
+ int tree_depth, level;
+ struct cds_ja_inode_flag *node_flag, *cur_node_depth[JA_MAX_DEPTH];
+ uint8_t cur_key[JA_MAX_DEPTH];
+ uint64_t _result_key = 0;
+ enum ja_direction dir;
+
+ switch (mode) {
+ case JA_LOOKUP_BE:
+ case JA_LOOKUP_AE:
+ if (caa_unlikely(key > ja->key_max || key == UINT64_MAX))
+ return NULL;
+ break;
+ default:
+ return NULL;
+ }
+
+ memset(cur_node_depth, 0, sizeof(cur_node_depth));
+ memset(cur_key, 0, sizeof(cur_key));
+ tree_depth = ja->tree_depth;
+ node_flag = rcu_dereference(ja->root);
+ cur_node_depth[0] = node_flag;
+
+ /* level 0: root node */
+ if (!ja_node_ptr(node_flag))
+ return NULL;
+
+ for (level = 1; level < tree_depth; level++) {
+ uint8_t iter_key;
+
+ iter_key = (uint8_t) (key >> (JA_BITS_PER_BYTE * (tree_depth - level - 1)));
+ node_flag = ja_node_get_nth(node_flag, NULL, iter_key);
+ if (!ja_node_ptr(node_flag))
+ break;
+ cur_key[level - 1] = iter_key;
+ cur_node_depth[level] = node_flag;
+ dbg_printf("cds_ja_lookup_inequality iter key lookup %u finds node_flag %p\n",
+ (unsigned int) iter_key, node_flag);
+ }
+
+ if (level == tree_depth) {
+ /* Last level lookup succeded. We got an equal match. */
+ if (result_key)
+ *result_key = key;
+ return (struct cds_ja_node *) node_flag;
+ }
+
+ /*
+ * Find highest value left/right of current node.
+ * Current node is cur_node_depth[level].
+ * Start at current level. If we cannot find any key left/right
+ * of ours, go one level up, seek highest value left/right of
+ * current (recursively), and when we find one, get the
+ * rightmost/leftmost child of its rightmost/leftmost child
+ * (recursively).
+ */
+ switch (mode) {
+ case JA_LOOKUP_BE:
+ dir = JA_LEFT;
+ break;
+ case JA_LOOKUP_AE:
+ dir = JA_RIGHT;
+ break;
+ default:
+ assert(0);
+ }
+ for (; level > 0; level--) {
+ uint8_t iter_key;
+
+ iter_key = (uint8_t) (key >> (JA_BITS_PER_BYTE * (tree_depth - level - 1)));
+ node_flag = ja_node_get_leftright(cur_node_depth[level - 1],
+ iter_key, &cur_key[level - 1], dir);
+ dbg_printf("cds_ja_lookup_inequality find sibling from %u at %u finds node_flag %p\n",
+ (unsigned int) iter_key, (unsigned int) cur_key[level - 1],
+ node_flag);
+ /* If found left/right sibling, find rightmost/leftmost child. */
+ if (ja_node_ptr(node_flag))
+ break;
+ }
+
+ if (!level) {
+ /* Reached the root and could not find a left/right sibling. */
+ return NULL;
+ }
+
+ level++;
+
+ /*
+ * From this point, we are guaranteed to be able to find a
+ * "below than"/"above than" match. ja_attach_node() and
+ * ja_detach_node() both guarantee that it is not possible for a
+ * lookup to reach a dead-end.
+ */
+
+ /*
+ * Find rightmost/leftmost child of rightmost/leftmost child
+ * (recursively).
+ */
+ switch (mode) {
+ case JA_LOOKUP_BE:
+ dir = JA_RIGHTMOST;
+ break;
+ case JA_LOOKUP_AE:
+ dir = JA_LEFTMOST;
+ break;
+ default:
+ assert(0);
+ }
+ for (; level < tree_depth; level++) {
+ node_flag = ja_node_get_minmax(node_flag, &cur_key[level - 1], dir);
+ dbg_printf("cds_ja_lookup_inequality find minmax at %u finds node_flag %p\n",
+ (unsigned int) cur_key[level - 1],
+ node_flag);
+ if (!ja_node_ptr(node_flag))
+ break;
+ }
+
+ assert(level == tree_depth);
+
+ if (result_key) {
+ for (level = 1; level < tree_depth; level++) {
+ _result_key |= ((uint64_t) cur_key[level - 1])
+ << (JA_BITS_PER_BYTE * (tree_depth - level - 1));
+ }
+ *result_key = _result_key;
+ }
+ return (struct cds_ja_node *) node_flag;
+}
+
+struct cds_ja_node *cds_ja_lookup_below_equal(struct cds_ja *ja,
+ uint64_t key, uint64_t *result_key)
+{
+ dbg_printf("cds_ja_lookup_below_equal key %" PRIu64 "\n", key);
+ return cds_ja_lookup_inequality(ja, key, result_key, JA_LOOKUP_BE);
+}
+
+struct cds_ja_node *cds_ja_lookup_above_equal(struct cds_ja *ja,
+ uint64_t key, uint64_t *result_key)
+{
+ dbg_printf("cds_ja_lookup_above_equal key %" PRIu64 "\n", key);
+ return cds_ja_lookup_inequality(ja, key, result_key, JA_LOOKUP_AE);
+}
+
+/*
+ * 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.
+ *
+ * ja_attach_node() ensures that a lookup will _never_ see a branch that
+ * leads to a dead-end: before attaching a branch, the entire content of
+ * the new branch is populated, thus creating a cluster, before
+ * attaching the cluster to the rest of the tree, thus making it visible
+ * to lookups.
+ */
+static
+int ja_attach_node(struct cds_ja *ja,
+ struct cds_ja_inode_flag **attach_node_flag_ptr,
+ struct cds_ja_inode_flag *attach_node_flag,
+ struct cds_ja_inode_flag *parent_attach_node_flag,
+ struct cds_ja_inode_flag **old_node_flag_ptr,
+ struct cds_ja_inode_flag *old_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_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 (old_node_flag %p, attach_node_flag_ptr %p attach_node_flag %p, parent_attach_node_flag %p)\n",
+ level, old_node_flag, attach_node_flag_ptr, attach_node_flag, parent_attach_node_flag);
+
+ assert(!old_node_flag);
+ if (attach_node_flag) {
+ shadow_node = rcuja_shadow_lookup_lock(ja->ht, attach_node_flag);
+ if (!shadow_node) {
+ ret = -EAGAIN;
+ goto end;
+ }
+ }
+ if (parent_attach_node_flag) {
+ parent_shadow_node = rcuja_shadow_lookup_lock(ja->ht,
+ parent_attach_node_flag);
+ if (!parent_shadow_node) {
+ ret = -EAGAIN;
+ goto unlock_shadow;
+ }
+ }
+
+ if (old_node_flag_ptr && ja_node_ptr(*old_node_flag_ptr)) {
+ /*
+ * Target node has been updated between RCU lookup and
+ * lock acquisition. We need to re-try lookup and
+ * attach.
+ */
+ ret = -EAGAIN;
+ goto unlock_parent;
+ }
+
+ /*
+ * Perform a lookup query to handle the case where
+ * old_node_flag_ptr is NULL. We cannot use it to check if the
+ * node has been populated between RCU lookup and mutex
+ * acquisition.
+ */
+ if (!old_node_flag_ptr) {
+ uint8_t iter_key;
+ struct cds_ja_inode_flag *lookup_node_flag;
+ struct cds_ja_inode_flag **lookup_node_flag_ptr;
+
+ iter_key = (uint8_t) (key >> (JA_BITS_PER_BYTE * (ja->tree_depth - level)));
+ lookup_node_flag = ja_node_get_nth(attach_node_flag,
+ &lookup_node_flag_ptr,
+ iter_key);
+ if (lookup_node_flag) {
+ ret = -EEXIST;
+ goto unlock_parent;
+ }
+ }
+
+ if (attach_node_flag_ptr && ja_node_ptr(*attach_node_flag_ptr) !=
+ ja_node_ptr(attach_node_flag)) {
+ /*
+ * Target node 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 */
+ iter_node_flag = (struct cds_ja_inode_flag *) child_node;
+
+ for (i = ja->tree_depth - 1; i >= (int) level; i--) {
+ uint8_t iter_key;
+
+ iter_key = (uint8_t) (key >> (JA_BITS_PER_BYTE * (ja->tree_depth - i - 1)));
+ dbg_printf("branch creation level %d, key %u\n",
+ i, (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, i);
+ if (ret) {
+ dbg_printf("branch creation error %d\n", ret);
+ goto check_error;
+ }
+ created_nodes[nr_created_nodes++] = iter_dest_node_flag;
+ iter_node_flag = iter_dest_node_flag;
+ }
+ assert(level > 0);
+
+ /* Publish branch */
+ if (level == 1) {
+ /*
+ * Attaching to root node.
+ */
+ rcu_assign_pointer(ja->root, iter_node_flag);
+ } else {
+ uint8_t iter_key;
+
+ iter_key = (uint8_t) (key >> (JA_BITS_PER_BYTE * (ja->tree_depth - level)));
+ dbg_printf("publish branch at level %d, key %u\n",
+ level - 1, (unsigned int) iter_key);
+ /* We need to use set_nth on the previous level. */
+ iter_dest_node_flag = attach_node_flag;
+ ret = ja_node_set_nth(ja, &iter_dest_node_flag,
+ iter_key,
+ iter_node_flag,
+ shadow_node, level - 1);
+ if (ret) {
+ dbg_printf("branch publish error %d\n", ret);
+ goto check_error;
+ }
+ /*
+ * Attach branch
+ */
+ rcu_assign_pointer(*attach_node_flag_ptr, iter_dest_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 pointer to list of duplicates, and add
+ * node to this list. 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_ja_inode_flag **node_flag_ptr,
+ struct cds_ja_inode_flag *node_flag,
+ struct cds_ja_node *last_node,
+ struct cds_ja_node *node)
+{
+ struct cds_ja_shadow_node *shadow_node;
+ struct cds_ja_node *iter_node;
+ int ret = 0, found = 0;
+
+ shadow_node = rcuja_shadow_lookup_lock(ja->ht, parent_node_flag);
+ if (!shadow_node) {
+ return -EAGAIN;
+ }
+ /*
+ * Ensure that previous node is still there at end of list.
+ */
+ iter_node = (struct cds_ja_node *) ja_node_ptr(node_flag);
+ if ((struct cds_ja_node *) ja_node_ptr(*node_flag_ptr) != iter_node) {
+ ret = -EAGAIN;
+ goto end;
+ }
+ cds_ja_for_each_duplicate(iter_node) {
+ if (iter_node == last_node)
+ found = 1;
+ }
+ if (!found) {
+ ret = -EAGAIN;
+ goto end;
+ }
+ /*
+ * Add node to tail of list to ensure that RCU traversals will
+ * always see either the prior node or the newly added if
+ * executed concurrently with a sequence of add followed by del
+ * on the same key. Safe against concurrent RCU read traversals.
+ */
+ node->next = NULL;
+ rcu_assign_pointer(last_node->next, node);
+end:
+ rcuja_shadow_unlock(shadow_node);
+ return ret;
+}
+
+static
+int _cds_ja_add(struct cds_ja *ja, uint64_t key,
+ struct cds_ja_node *node,
+ struct cds_ja_node **unique_node_ret)
+{
+ unsigned int tree_depth, i;
+ struct cds_ja_inode_flag *attach_node_flag,
+ *parent_node_flag,
+ *parent2_node_flag,
+ *node_flag,
+ *parent_attach_node_flag;
+ struct cds_ja_inode_flag **attach_node_flag_ptr,
+ **parent_node_flag_ptr,
+ **node_flag_ptr;
+ int ret;
+
+ if (caa_unlikely(key > ja->key_max || key == UINT64_MAX)) {
+ return -EINVAL;
+ }
+ tree_depth = ja->tree_depth;
+
+retry:
+ dbg_printf("cds_ja_add attempt: key %" PRIu64 ", node %p\n",
+ key, node);
+ parent2_node_flag = NULL;
+ parent_node_flag =
+ (struct cds_ja_inode_flag *) &ja->root; /* Use root ptr address as key for mutex */
+ parent_node_flag_ptr = NULL;
+ node_flag = rcu_dereference(ja->root);
+ node_flag_ptr = &ja->root;
+
+ /* Iterate on all internal levels */
+ for (i = 1; i < tree_depth; i++) {
+ uint8_t iter_key;
+
+ if (!ja_node_ptr(node_flag))
+ break;
+ dbg_printf("cds_ja_add iter parent2_node_flag %p parent_node_flag %p node_flag_ptr %p node_flag %p\n",
+ parent2_node_flag, parent_node_flag, node_flag_ptr, node_flag);
+ iter_key = (uint8_t) (key >> (JA_BITS_PER_BYTE * (tree_depth - i - 1)));
+ parent2_node_flag = parent_node_flag;
+ parent_node_flag = node_flag;
+ parent_node_flag_ptr = node_flag_ptr;
+ node_flag = ja_node_get_nth(node_flag,
+ &node_flag_ptr,
+ iter_key);
+ }
+
+ /*
+ * We reached either bottom of tree or internal NULL node,
+ * 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 NULL parent2_node_flag %p parent_node_flag %p node_flag_ptr %p node_flag %p\n",
+ parent2_node_flag, parent_node_flag, node_flag_ptr, node_flag);
+
+ attach_node_flag = parent_node_flag;
+ attach_node_flag_ptr = parent_node_flag_ptr;
+ parent_attach_node_flag = parent2_node_flag;
+
+ ret = ja_attach_node(ja, attach_node_flag_ptr,
+ attach_node_flag,
+ parent_attach_node_flag,
+ node_flag_ptr,
+ node_flag,
+ key, i, node);
+ } else {
+ struct cds_ja_node *iter_node, *last_node = NULL;
+
+ if (unique_node_ret) {
+ *unique_node_ret = (struct cds_ja_node *) ja_node_ptr(node_flag);
+ return -EEXIST;
+ }
+
+ /* Find last duplicate */
+ iter_node = (struct cds_ja_node *) ja_node_ptr(node_flag);
+ cds_ja_for_each_duplicate_rcu(iter_node)
+ last_node = iter_node;
+
+ dbg_printf("cds_ja_add duplicate parent2_node_flag %p parent_node_flag %p node_flag_ptr %p node_flag %p\n",
+ parent2_node_flag, parent_node_flag, node_flag_ptr, node_flag);
+
+ attach_node_flag = node_flag;
+ attach_node_flag_ptr = node_flag_ptr;
+ parent_attach_node_flag = parent_node_flag;
+
+ ret = ja_chain_node(ja,
+ parent_attach_node_flag,
+ attach_node_flag_ptr,
+ attach_node_flag,
+ last_node,
+ node);
+ }
+ if (ret == -EAGAIN || ret == -EEXIST)
+ goto retry;
+
+ return ret;
+}
+
+int cds_ja_add(struct cds_ja *ja, uint64_t key,
+ struct cds_ja_node *node)
+{
+ return _cds_ja_add(ja, key, node, NULL);
+}
+
+struct cds_ja_node *cds_ja_add_unique(struct cds_ja *ja, uint64_t key,
+ struct cds_ja_node *node)
+{
+ int ret;
+ struct cds_ja_node *ret_node;
+
+ ret = _cds_ja_add(ja, key, node, &ret_node);
+ if (ret == -EEXIST)
+ return ret_node;
+ else
+ return node;
+}
+
+/*
+ * 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.
+ *
+ * ja_detach_node() ensures that a lookup will _never_ see a branch that
+ * leads to a dead-end: when removing branch, it makes sure to perform
+ * the "cut" at the highest node that has only one child, effectively
+ * replacing it with a NULL pointer.
+ */
+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;
+ }
+ shadow_nodes[nr_shadow++] = shadow_node;
+
+ /*
+ * Check if node has been removed between RCU
+ * lookup and lock acquisition.
+ */
+ assert(snapshot_ptr[i + 1]);
+ if (ja_node_ptr(*snapshot_ptr[i + 1])
+ != ja_node_ptr(snapshot[i + 1])) {
+ ret = -ENOENT;
+ goto end;
+ }
+
+ assert(shadow_node->nr_child > 0);
+ 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;
+
+ /*
+ * Check if node has been removed between RCU
+ * lookup and lock acquisition.
+ */
+ assert(snapshot_ptr[i]);
+ if (ja_node_ptr(*snapshot_ptr[i])
+ != ja_node_ptr(snapshot[i])) {
+ ret = -ENOENT;
+ goto end;
+ }
+
+ 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;
+
+ /*
+ * Check if node has been removed between RCU
+ * lookup and lock acquisition.
+ */
+ assert(snapshot_ptr[i - 1]);
+ if (ja_node_ptr(*snapshot_ptr[i - 1])
+ != ja_node_ptr(snapshot[i - 1])) {
+ ret = -ENOENT;
+ goto end;
+ }
+ }
+
+ break;
+ }
+ }
+
+ /*
+ * 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 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 */
+ if (nr_branch < 1)
+ abort(); /* Should never happen. */
+ 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, nr_branch - 1);
+ 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_unchain_node(struct cds_ja *ja,
+ struct cds_ja_inode_flag *parent_node_flag,
+ struct cds_ja_inode_flag **node_flag_ptr,
+ struct cds_ja_inode_flag *node_flag,
+ struct cds_ja_node *node)
+{
+ struct cds_ja_shadow_node *shadow_node;
+ struct cds_ja_node *iter_node, **iter_node_ptr, **prev_node_ptr = NULL;
+ int ret = 0, count = 0, found = 0;
+
+ shadow_node = rcuja_shadow_lookup_lock(ja->ht, parent_node_flag);
+ if (!shadow_node)
+ return -EAGAIN;
+ if (ja_node_ptr(*node_flag_ptr) != ja_node_ptr(node_flag)) {
+ ret = -EAGAIN;
+ goto end;
+ }
+ /*
+ * Find the previous node's next pointer pointing to our node,
+ * so we can update it. Retry if another thread removed all but
+ * one of duplicates since check (this check was performed
+ * without lock). Ensure that the node we are about to remove is
+ * still in the list (while holding lock). No need for RCU
+ * traversal here since we hold the lock on the parent.
+ */
+ iter_node_ptr = (struct cds_ja_node **) node_flag_ptr;
+ iter_node = (struct cds_ja_node *) ja_node_ptr(node_flag);
+ cds_ja_for_each_duplicate(iter_node) {
+ count++;
+ if (iter_node == node) {
+ prev_node_ptr = iter_node_ptr;
+ found++;
+ }
+ iter_node_ptr = &iter_node->next;
+ }
+ assert(found <= 1);
+ if (!found || count == 1) {
+ ret = -EAGAIN;
+ goto end;
+ }
+ CMM_STORE_SHARED(*prev_node_ptr, node->next);
+ /*
+ * Validate that we indeed removed the node from linked list.
+ */
+ assert(ja_node_ptr(*node_flag_ptr) != (struct cds_ja_inode *) node);
+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,
+ **node_flag_ptr;
+ int nr_snapshot;
+ int ret;
+
+ if (caa_unlikely(key > ja->key_max || key == UINT64_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;
+ 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,
+ &node_flag_ptr,
+ iter_key);
+ if (node_flag)
+ prev_node_flag_ptr = node_flag_ptr;
+ 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_ja_node *iter_node, *match = NULL;
+ int count = 0;
+
+ iter_node = (struct cds_ja_node *) ja_node_ptr(node_flag);
+ cds_ja_for_each_duplicate_rcu(iter_node) {
+ dbg_printf("cds_ja_del: compare %p with iter_node %p\n", node, iter_node);
+ if (iter_node == node)
+ match = iter_node;
+ 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],
+ node_flag_ptr, node_flag, 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, 0);
+ 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;
+}
+
+static
+void print_debug_fallback_distribution(struct cds_ja *ja)
+{
+ int i;
+
+ fprintf(stderr, "Fallback node distribution:\n");
+ for (i = 0; i < JA_ENTRY_PER_NODE; i++) {
+ if (!ja->node_fallback_count_distribution[i])
+ continue;
+ fprintf(stderr, " %3u: %4lu\n",
+ i, ja->node_fallback_count_distribution[i]);
+ }
+}
+
+static
+int ja_final_checks(struct cds_ja *ja)
+{
+ double fallback_ratio;
+ unsigned long na, nf, nr_fallback;
+ int ret = 0;
+
+ if (!ja_debug_counters())
+ return 0;
+
+ fallback_ratio = (double) uatomic_read(&ja->nr_fallback);
+ fallback_ratio /= (double) uatomic_read(&ja->nr_nodes_allocated);
+ nr_fallback = uatomic_read(&ja->nr_fallback);
+ if (nr_fallback)
+ fprintf(stderr,
+ "[warning] RCU Judy Array used %lu fallback node(s) (ratio: %g)\n",
+ uatomic_read(&ja->nr_fallback),
+ fallback_ratio);
+
+ na = uatomic_read(&ja->nr_nodes_allocated);
+ nf = uatomic_read(&ja->nr_nodes_freed);
+ dbg_printf("Nodes allocated: %lu, Nodes freed: %lu.\n", na, nf);
+ if (nr_fallback)
+ print_debug_fallback_distribution(ja);
+
+ if (na != nf) {
+ fprintf(stderr, "[error] Judy array leaked %ld nodes. Allocated: %lu, freed: %lu.\n",
+ (long) na - nf, na, nf);
+ ret = -1;
+ }
+ return ret;
+}
+
+/*
+ * There should be no more concurrent add, delete, nor look-up performed
+ * on the Judy array while it is being destroyed (ensured by the
+ * caller).
+ */
+int cds_ja_destroy(struct cds_ja *ja)
+{
+ const struct rcu_flavor_struct *flavor;
+ int ret;
+
+ flavor = cds_lfht_rcu_flavor(ja->ht);
+ rcuja_shadow_prune(ja->ht,
+ RCUJA_SHADOW_CLEAR_FREE_NODE | RCUJA_SHADOW_CLEAR_FREE_LOCK);
+ flavor->thread_offline();
+ ret = rcuja_delete_ht(ja->ht);
+ if (ret)
+ return ret;
+
+ /* Wait for in-flight call_rcu free to complete. */
+ flavor->barrier();
+
+ flavor->thread_online();
+ ret = ja_final_checks(ja);
+ free(ja);
+ return ret;
+}
projects / userspace-rcu.git / blobdiff