From: Mathieu Desnoyers Date: Mon, 30 Jul 2012 03:47:36 +0000 (-0400) Subject: rcuja: introduce union to represent nodes X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=1db4943cd6737d7a9be541f825ec94149b61fbf7;p=userspace-rcu.git rcuja: introduce union to represent nodes Signed-off-by: Mathieu Desnoyers --- diff --git a/rcuja/rcuja.c b/rcuja/rcuja.c index 6b69fc8..586b29b 100644 --- a/rcuja/rcuja.c +++ b/rcuja/rcuja.c @@ -40,6 +40,7 @@ enum rcu_ja_type_class { /* 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, }; struct rcu_ja_type { @@ -82,64 +83,139 @@ struct rcu_ja_type { #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, +}; + +enum { + ja_type_5_nr_pool_order = 1, + ja_type_6_nr_pool_order = 2, +}; + 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, }, + { .type_class = RCU_JA_LINEAR, .min_child = 1, .max_child = ja_type_0_max_child, .order = 3, }, + { .type_class = RCU_JA_LINEAR, .min_child = 1, .max_child = ja_type_1_max_child, .order = 4, }, + { .type_class = RCU_JA_LINEAR, .min_child = 3, .max_child = ja_type_2_max_child, .order = 5, }, + { .type_class = RCU_JA_LINEAR, .min_child = 4, .max_child = ja_type_3_max_child, .order = 6, }, + { .type_class = RCU_JA_LINEAR, .min_child = 10, .max_child = ja_type_4_max_child, .order = 7, }, /* Pools may fill sooner than max_child */ - { .type_class = RCU_JA_POOL, .min_child = 20, .max_child = 48, .order = 8, .nr_pool_order = 1, .pool_size_order = 7, }, - { .type_class = RCU_JA_POOL, .min_child = 45, .max_child = 92, .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, .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, .order = 9, .nr_pool_order = ja_type_6_nr_pool_order, .pool_size_order = 7, }, /* * 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 = 256, .order = 10, }, + { .type_class = RCU_JA_PIGEON, .min_child = 89, .max_child = ja_type_7_max_child, .order = 10, }, }; -CAA_BUILD_BUG_ON(CAA_ARRAY_SIZE(ja_types) > JA_TYPE_MAX_NR); #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, +}; + +enum { + ja_type_5_nr_pool_order = 1, + ja_type_6_nr_pool_order = 2, +}; + 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, }, + { .type_class = RCU_JA_LINEAR, .min_child = 1, .max_child = ja_type_0_max_child, .order = 4, }, + { .type_class = RCU_JA_LINEAR, .min_child = 1, .max_child = ja_type_1_max_child, .order = 5, }, + { .type_class = RCU_JA_LINEAR, .min_child = 3, .max_child = ja_type_2_max_child, .order = 6, }, + { .type_class = RCU_JA_LINEAR, .min_child = 5, .max_child = ja_type_3_max_child, .order = 7, }, + { .type_class = RCU_JA_LINEAR, .min_child = 10, .max_child = ja_type_4_max_child, .order = 8, }, /* Pools may fill sooner than max_child. */ - { .type_class = RCU_JA_POOL, .min_child = 22, .max_child = 54, .order = 9, .nr_pool_order = 1, .pool_size_order = 8, }, - { .type_class = RCU_JA_POOL, .min_child = 51, .max_child = 104, .order = 10, .nr_pool_order = 2, .pool_size_order = 8, }, + { .type_class = RCU_JA_POOL, .min_child = 22, .max_child = ja_type_5_max_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, .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 = 256, .order = 11, }, + { .type_class = RCU_JA_PIGEON, .min_child = 101, .max_child = ja_type_7_max_child, .order = 11, }, }; -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); +} + +/* Never declared. Opaque type used to store flagged node pointers. */ +struct rcu_ja_node_flag; + /* - * 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 rcu_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_child]; \ + struct rcu_ja_node_flag *child_ptr[ja_type_## index ##_max_child]; \ + } + +#define DECLARE_POOL_NODE(index) \ + struct { \ + struct { \ + uint8_t nr_child; \ + uint8_t child_value[ja_type_## index ##_max_child >> ja_type_## index ##_nr_pool_order]; \ + struct rcu_ja_node_flag *child_ptr[ja_type_## index ##_max_child >> ja_type_## index ##_nr_pool_order]; \ + } linear[1U << ja_type_## index ##_nr_pool_order]; \ + } + struct rcu_ja_node { - char data[]; + 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 rcu_ja_node_flag *child[ja_type_7_max_child]; + } conf_7; + /* data aliasing nodes for computed accesses */ + uint8_t data[sizeof(struct rcu_ja_node_flag *) * ja_type_7_max_child]; + } u; }; -/* Never declared. Opaque type used to store flagged node pointers. */ -struct rcu_ja_node_flag; - static struct rcu_ja_node_flag *ja_node_flag(struct rcu_ja_node *node, unsigned int type) { - assert(type < JA_TYPE_NR); + assert(type < RCU_JA_NR_TYPES); return (struct rcu_ja_node_flag *) (((unsigned long) node) | type); } @@ -149,7 +225,7 @@ unsigned int ja_node_type(struct rcu_ja_node_flag *node) unsigned int type; type = (unsigned int) ((unsigned long) node & JA_TYPE_MASK); - assert(type < JA_TYPE_NR); + assert(type < RCU_JA_NR_TYPES); return type; } @@ -161,7 +237,7 @@ struct rcu_ja_node *ja_node_ptr(struct rcu_ja_node_flag *node) struct rcu_ja_node *alloc_rcu_ja_node(struct rcu_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) @@ -175,9 +251,9 @@ void free_rcu_ja_node(struct rcu_ja_node *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 @@ -187,18 +263,18 @@ struct rcu_ja_node_flag *ja_linear_node_get_nth(const struct rcu_ja_type *type, { uint8_t nr_child; uint8_t *values; - struct rcu_ja_node_flag *pointers; + struct rcu_ja_node_flag **pointers; struct rcu_ja_node_flag *ptr; unsigned int i; assert(!type || type->type_class == RCU_JA_LINEAR); - nr_child = node->data[0]; + nr_child = node->u.data[0]; cmm_smp_rmb(); /* read nr_child before values */ assert(!type || nr_child <= type->max_child); assert(!type || nr_child >= type->min_child); - values = &node[1]; + values = &node->u.data[1]; for (i = 0; i < nr_child; i++) { if (values[i] == n) break; @@ -206,7 +282,7 @@ struct rcu_ja_node_flag *ja_linear_node_get_nth(const struct rcu_ja_type *type, if (i >= nr_child) return NULL; cmm_smp_rmb(); /* read values before pointer */ - pointers = align_ptr_size(&values[nr_child]); + pointers = (struct rcu_ja_node_flag **) align_ptr_size(&values[nr_child]); ptr = pointers[i]; assert(ja_node_ptr(ptr) != NULL); return ptr; @@ -217,12 +293,11 @@ struct rcu_ja_node_flag *ja_pool_node_get_nth(const struct rcu_ja_type *type, struct rcu_ja_node *node, uint8_t n) { - struct rcu_ja_node_flag *ptr; struct rcu_ja_node *linear; assert(type->type_class == RCU_JA_POOL); linear = (struct rcu_ja_node *) - &node->data[((unsigned long) n >> (CHAR_BIT - type->nr_pool_order)) << type->pool_size_order]; + &node->u.data[((unsigned long) n >> (CHAR_BIT - type->nr_pool_order)) << type->pool_size_order]; return ja_linear_node_get_nth(NULL, linear, n); } @@ -232,7 +307,7 @@ struct rcu_ja_node_flag *ja_pigeon_node_get_nth(const struct rcu_ja_type *type, uint8_t n) { assert(type->type_class == RCU_JA_PIGEON); - return ((struct rcu_ja_node_flag *) node->data)[n]; + return ((struct rcu_ja_node_flag **) node->u.data)[n]; } /* ja_node_get_nth: get nth item from a node */