* operation.
* - The resize operation for larger tables (and available through an
* API) allows both expanding and shrinking the hash table.
- * - Per-CPU Split-counters are used to keep track of the number of
+ * - Split-counters are used to keep track of the number of
* nodes within the hash table for automatic resize triggering.
* - Resize operation initiated by long chain detection is executed by a
* call_rcu thread, which keeps lock-freedom of add and remove.
* the "dummy node" tables.
* - There is one dummy node table per hash index order. The size of
* each dummy node table is half the number of hashes contained in
- * this order.
- * - call_rcu is used to garbage-collect the old order table.
+ * this order (except for order 0).
+ * - synchronzie_rcu is used to garbage-collect the old dummy node table.
* - The per-order dummy node tables contain a compact version of the
* hash table nodes. These tables are invariant after they are
* populated into the hash table.
- *
+ *
+ * Dummy node tables:
+ *
+ * hash table hash table the last all dummy node tables
+ * order size dummy node 0 1 2 3 4 5 6(index)
+ * table size
+ * 0 1 1 1
+ * 1 2 1 1 1
+ * 2 4 2 1 1 2
+ * 3 8 4 1 1 2 4
+ * 4 16 8 1 1 2 4 8
+ * 5 32 16 1 1 2 4 8 16
+ * 6 64 32 1 1 2 4 8 16 32
+ *
+ * When growing/shrinking, we only focus on the last dummy node table
+ * which size is (!order ? 1 : (1 << (order -1))).
+ *
+ * Example for growing/shrinking:
+ * grow hash table from order 5 to 6: init the index=6 dummy node table
+ * shrink hash table from order 6 to 5: fini the index=6 dummy node table
+ *
* A bit of ascii art explanation:
*
* Order index is the off-by-one compare to the actual power of 2 because
*
* order bits reverse
* 0 0 000 000
- * |
- * 1 | 1 001 100 <- <-
- * | | | |
- * 2 | | 2 010 010 | |
+ * 1 | 1 001 100 <-
+ * 2 | | 2 010 010 <- |
* | | | 3 011 110 | <- |
- * | | | | | | |
* 3 -> | | | 4 100 001 | |
* -> | | 5 101 101 |
* -> | 6 110 011
#include <stdint.h>
#include <string.h>
+#include "config.h"
#include <urcu.h>
#include <urcu-call-rcu.h>
#include <urcu/arch.h>
#endif
/*
- * Per-CPU split-counters lazily update the global counter each 1024
+ * Split-counters lazily update the global counter each 1024
* addition/removal. It automatically keeps track of resize required.
* We use the bucket length as indicator for need to expand for small
* tables and machines lacking per-cpu data suppport.
*/
#define COUNT_COMMIT_ORDER 10
+#define DEFAULT_SPLIT_COUNT_MASK 0xFUL
#define CHAIN_LEN_TARGET 1
#define CHAIN_LEN_RESIZE_THRESHOLD 3
/* Value of the end pointer. Should not interact with flags. */
#define END_VALUE NULL
+/*
+ * ht_items_count: Split-counters counting the number of node addition
+ * and removal in the table. Only used if the CDS_LFHT_ACCOUNTING flag
+ * is set at hash table creation.
+ *
+ * These are free-running counters, never reset to zero. They count the
+ * number of add/remove, and trigger every (1 << COUNT_COMMIT_ORDER)
+ * operations to update the global counter. We choose a power-of-2 value
+ * for the trigger to deal with 32 or 64-bit overflow of the counter.
+ */
struct ht_items_count {
unsigned long add, del;
} __attribute__((aligned(CAA_CACHE_LINE_SIZE)));
+/*
+ * rcu_level: Contains the per order-index-level dummy node table. The
+ * size of each dummy node table is half the number of hashes contained
+ * in this order (except for order 0). The minimum allocation size
+ * parameter allows combining the dummy node arrays of the lowermost
+ * levels to improve cache locality for small index orders.
+ */
struct rcu_level {
- struct rcu_head head;
+ /* Note: manually update allocation length when adding a field */
struct _cds_lfht_node nodes[0];
};
+/*
+ * rcu_table: Contains the size and desired new size if a resize
+ * operation is in progress, as well as the statically-sized array of
+ * rcu_level pointers.
+ */
struct rcu_table {
unsigned long size; /* always a power of 2, shared (RCU) */
unsigned long resize_target;
struct rcu_level *tbl[MAX_TABLE_ORDER];
};
+/*
+ * cds_lfht: Top-level data structure representing a lock-free hash
+ * table. Defined in the implementation file to make it be an opaque
+ * cookie to users.
+ */
struct cds_lfht {
struct rcu_table t;
cds_lfht_hash_fct hash_fct;
cds_lfht_compare_fct compare_fct;
+ unsigned long min_alloc_order;
+ unsigned long min_alloc_size;
unsigned long hash_seed;
int flags;
/*
void (*cds_lfht_rcu_unregister_thread)(void);
pthread_attr_t *resize_attr; /* Resize threads attributes */
long count; /* global approximate item count */
- struct ht_items_count *percpu_count; /* per-cpu item count */
+ struct ht_items_count *split_count; /* split item count */
};
+/*
+ * rcu_resize_work: Contains arguments passed to RCU worker thread
+ * responsible for performing lazy resize.
+ */
struct rcu_resize_work {
struct rcu_head head;
struct cds_lfht *ht;
};
+/*
+ * partition_resize_work: Contains arguments passed to worker threads
+ * executing the hash table resize on partitions of the hash table
+ * assigned to each processor's worker thread.
+ */
struct partition_resize_work {
- struct rcu_head head;
+ pthread_t thread_id;
struct cds_lfht *ht;
unsigned long i, start, len;
void (*fct)(struct cds_lfht *ht, unsigned long i,
unsigned long start, unsigned long len);
};
-enum add_mode {
- ADD_DEFAULT = 0,
- ADD_UNIQUE = 1,
- ADD_REPLACE = 2,
-};
-
static
-struct cds_lfht_node *_cds_lfht_add(struct cds_lfht *ht,
- unsigned long size,
- struct cds_lfht_node *node,
- enum add_mode mode, int dummy);
+void _cds_lfht_add(struct cds_lfht *ht,
+ unsigned long size,
+ struct cds_lfht_node *node,
+ struct cds_lfht_iter *unique_ret,
+ int dummy);
/*
* Algorithm to reverse bits in a word by lookup table, extended to
unsigned int fls_ulong(unsigned long x)
{
-#if (CAA_BITS_PER_lONG == 32)
+#if (CAA_BITS_PER_LONG == 32)
return fls_u32(x);
#else
return fls_u64(x);
#endif
}
+/*
+ * Return the minimum order for which x <= (1UL << order).
+ * Return -1 if x is 0.
+ */
int get_count_order_u32(uint32_t x)
{
- int order;
+ if (!x)
+ return -1;
- order = fls_u32(x) - 1;
- if (x & (x - 1))
- order++;
- return order;
+ return fls_u32(x - 1);
}
+/*
+ * Return the minimum order for which x <= (1UL << order).
+ * Return -1 if x is 0.
+ */
int get_count_order_ulong(unsigned long x)
{
- int order;
+ if (!x)
+ return -1;
- order = fls_ulong(x) - 1;
- if (x & (x - 1))
- order++;
- return order;
+ return fls_ulong(x - 1);
}
#ifdef POISON_FREE
-#define poison_free(ptr) \
- do { \
- memset(ptr, 0x42, sizeof(*(ptr))); \
- free(ptr); \
+#define poison_free(ptr) \
+ do { \
+ if (ptr) { \
+ memset(ptr, 0x42, sizeof(*(ptr))); \
+ free(ptr); \
+ } \
} while (0)
#else
#define poison_free(ptr) free(ptr)
static
void cds_lfht_resize_lazy(struct cds_lfht *ht, unsigned long size, int growth);
-/*
- * If the sched_getcpu() and sysconf(_SC_NPROCESSORS_CONF) calls are
- * available, then we support hash table item accounting.
- * In the unfortunate event the number of CPUs reported would be
- * inaccurate, we use modulo arithmetic on the number of CPUs we got.
- */
-#if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF)
-
static
void cds_lfht_resize_lazy_count(struct cds_lfht *ht, unsigned long size,
unsigned long count);
static long nr_cpus_mask = -1;
+static long split_count_mask = -1;
+
+#if defined(HAVE_SYSCONF)
+static void ht_init_nr_cpus_mask(void)
+{
+ long maxcpus;
+
+ maxcpus = sysconf(_SC_NPROCESSORS_CONF);
+ if (maxcpus <= 0) {
+ nr_cpus_mask = -2;
+ return;
+ }
+ /*
+ * round up number of CPUs to next power of two, so we
+ * can use & for modulo.
+ */
+ maxcpus = 1UL << get_count_order_ulong(maxcpus);
+ nr_cpus_mask = maxcpus - 1;
+}
+#else /* #if defined(HAVE_SYSCONF) */
+static void ht_init_nr_cpus_mask(void)
+{
+ nr_cpus_mask = -2;
+}
+#endif /* #else #if defined(HAVE_SYSCONF) */
static
-struct ht_items_count *alloc_per_cpu_items_count(void)
+void alloc_split_items_count(struct cds_lfht *ht)
{
struct ht_items_count *count;
- switch (nr_cpus_mask) {
- case -2:
- return NULL;
- case -1:
- {
- long maxcpus;
-
- maxcpus = sysconf(_SC_NPROCESSORS_CONF);
- if (maxcpus <= 0) {
- nr_cpus_mask = -2;
- return NULL;
- }
- /*
- * round up number of CPUs to next power of two, so we
- * can use & for modulo.
- */
- maxcpus = 1UL << get_count_order_ulong(maxcpus);
- nr_cpus_mask = maxcpus - 1;
+ if (nr_cpus_mask == -1) {
+ ht_init_nr_cpus_mask();
+ if (nr_cpus_mask < 0)
+ split_count_mask = DEFAULT_SPLIT_COUNT_MASK;
+ else
+ split_count_mask = nr_cpus_mask;
}
- /* Fall-through */
- default:
- return calloc(nr_cpus_mask + 1, sizeof(*count));
+
+ assert(split_count_mask >= 0);
+
+ if (ht->flags & CDS_LFHT_ACCOUNTING) {
+ ht->split_count = calloc(split_count_mask + 1, sizeof(*count));
+ assert(ht->split_count);
+ } else {
+ ht->split_count = NULL;
}
}
static
-void free_per_cpu_items_count(struct ht_items_count *count)
+void free_split_items_count(struct cds_lfht *ht)
{
- poison_free(count);
+ poison_free(ht->split_count);
}
+#if defined(HAVE_SCHED_GETCPU)
static
-int ht_get_cpu(void)
+int ht_get_split_count_index(unsigned long hash)
{
int cpu;
- assert(nr_cpus_mask >= 0);
+ assert(split_count_mask >= 0);
cpu = sched_getcpu();
if (unlikely(cpu < 0))
- return cpu;
+ return hash & split_count_mask;
else
- return cpu & nr_cpus_mask;
+ return cpu & split_count_mask;
}
+#else /* #if defined(HAVE_SCHED_GETCPU) */
+static
+int ht_get_split_count_index(unsigned long hash)
+{
+ return hash & split_count_mask;
+}
+#endif /* #else #if defined(HAVE_SCHED_GETCPU) */
static
-void ht_count_add(struct cds_lfht *ht, unsigned long size)
+void ht_count_add(struct cds_lfht *ht, unsigned long size, unsigned long hash)
{
- unsigned long percpu_count;
- int cpu;
+ unsigned long split_count;
+ int index;
- if (unlikely(!ht->percpu_count))
- return;
- cpu = ht_get_cpu();
- if (unlikely(cpu < 0))
+ if (unlikely(!ht->split_count))
return;
- percpu_count = uatomic_add_return(&ht->percpu_count[cpu].add, 1);
- if (unlikely(!(percpu_count & ((1UL << COUNT_COMMIT_ORDER) - 1)))) {
+ index = ht_get_split_count_index(hash);
+ split_count = uatomic_add_return(&ht->split_count[index].add, 1);
+ if (unlikely(!(split_count & ((1UL << COUNT_COMMIT_ORDER) - 1)))) {
long count;
- dbg_printf("add percpu %lu\n", percpu_count);
+ dbg_printf("add split count %lu\n", split_count);
count = uatomic_add_return(&ht->count,
1UL << COUNT_COMMIT_ORDER);
/* If power of 2 */
}
static
-void ht_count_del(struct cds_lfht *ht, unsigned long size)
+void ht_count_del(struct cds_lfht *ht, unsigned long size, unsigned long hash)
{
- unsigned long percpu_count;
- int cpu;
+ unsigned long split_count;
+ int index;
- if (unlikely(!ht->percpu_count))
- return;
- cpu = ht_get_cpu();
- if (unlikely(cpu < 0))
+ if (unlikely(!ht->split_count))
return;
- percpu_count = uatomic_add_return(&ht->percpu_count[cpu].del, 1);
- if (unlikely(!(percpu_count & ((1UL << COUNT_COMMIT_ORDER) - 1)))) {
+ index = ht_get_split_count_index(hash);
+ split_count = uatomic_add_return(&ht->split_count[index].del, 1);
+ if (unlikely(!(split_count & ((1UL << COUNT_COMMIT_ORDER) - 1)))) {
long count;
- dbg_printf("del percpu %lu\n", percpu_count);
+ dbg_printf("del split count %lu\n", split_count);
count = uatomic_add_return(&ht->count,
-(1UL << COUNT_COMMIT_ORDER));
/* If power of 2 */
* Don't shrink table if the number of nodes is below a
* certain threshold.
*/
- if (count < (1UL << COUNT_COMMIT_ORDER) * (nr_cpus_mask + 1))
+ if (count < (1UL << COUNT_COMMIT_ORDER) * (split_count_mask + 1))
return;
cds_lfht_resize_lazy_count(ht, size,
count >> (CHAIN_LEN_TARGET - 1));
}
}
-#else /* #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) */
-
-static const long nr_cpus_mask = -2;
-
-static
-struct ht_items_count *alloc_per_cpu_items_count(void)
-{
- return NULL;
-}
-
-static
-void free_per_cpu_items_count(struct ht_items_count *count)
-{
-}
-
-static
-void ht_count_add(struct cds_lfht *ht, unsigned long size)
-{
-}
-
-static
-void ht_count_del(struct cds_lfht *ht, unsigned long size)
-{
-}
-
-#endif /* #else #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) */
-
-
static
void check_resize(struct cds_lfht *ht, unsigned long size, uint32_t chain_len)
{
}
static
-void cds_lfht_free_level(struct rcu_head *head)
+struct _cds_lfht_node *lookup_bucket(struct cds_lfht *ht, unsigned long size,
+ unsigned long hash)
{
- struct rcu_level *l =
- caa_container_of(head, struct rcu_level, head);
- poison_free(l);
+ unsigned long index, order;
+
+ assert(size > 0);
+ index = hash & (size - 1);
+
+ if (index < ht->min_alloc_size) {
+ dbg_printf("lookup hash %lu index %lu order 0 aridx 0\n",
+ hash, index);
+ return &ht->t.tbl[0]->nodes[index];
+ }
+ /*
+ * equivalent to get_count_order_ulong(index + 1), but optimizes
+ * away the non-existing 0 special-case for
+ * get_count_order_ulong.
+ */
+ order = fls_ulong(index);
+ dbg_printf("lookup hash %lu index %lu order %lu aridx %lu\n",
+ hash, index, order, index & ((1UL << (order - 1)) - 1));
+ return &ht->t.tbl[order]->nodes[index & ((1UL << (order - 1)) - 1)];
}
/*
iter_prev = dummy;
/* We can always skip the dummy node initially */
iter = rcu_dereference(iter_prev->p.next);
+ assert(!is_removed(iter));
assert(iter_prev->p.reverse_hash <= node->p.reverse_hash);
/*
* We should never be called with dummy (start of chain)
new_next = flag_dummy(clear_flag(next));
else
new_next = clear_flag(next);
- if (is_removed(iter))
- new_next = flag_removed(new_next);
(void) uatomic_cmpxchg(&iter_prev->p.next, iter, new_next);
}
return;
static
int _cds_lfht_replace(struct cds_lfht *ht, unsigned long size,
struct cds_lfht_node *old_node,
- struct cds_lfht_node *ret_next,
+ struct cds_lfht_node *old_next,
struct cds_lfht_node *new_node)
{
- struct cds_lfht_node *dummy, *old_next;
+ struct cds_lfht_node *dummy, *ret_next;
struct _cds_lfht_node *lookup;
- int flagged = 0;
- unsigned long hash, index, order;
if (!old_node) /* Return -ENOENT if asked to replace NULL node */
- goto end;
+ return -ENOENT;
assert(!is_removed(old_node));
assert(!is_dummy(old_node));
assert(!is_removed(new_node));
assert(!is_dummy(new_node));
assert(new_node != old_node);
- do {
+ for (;;) {
/* Insert after node to be replaced */
- old_next = ret_next;
if (is_removed(old_next)) {
/*
* Too late, the old node has been removed under us
* between lookup and replace. Fail.
*/
- goto end;
+ return -ENOENT;
}
assert(!is_dummy(old_next));
assert(new_node != clear_flag(old_next));
*/
ret_next = uatomic_cmpxchg(&old_node->p.next,
old_next, flag_removed(new_node));
- } while (ret_next != old_next);
-
- /* We performed the replacement. */
- flagged = 1;
+ if (ret_next == old_next)
+ break; /* We performed the replacement. */
+ old_next = ret_next;
+ }
/*
* Ensure that the old node is not visible to readers anymore:
* lookup for the node, and remove it (along with any other
* logically removed node) if found.
*/
- hash = bit_reverse_ulong(old_node->p.reverse_hash);
- assert(size > 0);
- index = hash & (size - 1);
- order = get_count_order_ulong(index + 1);
- lookup = &ht->t.tbl[order]->nodes[index & (!order ? 0 : ((1UL << (order - 1)) - 1))];
+ lookup = lookup_bucket(ht, size, bit_reverse_ulong(old_node->p.reverse_hash));
dummy = (struct cds_lfht_node *) lookup;
_cds_lfht_gc_bucket(dummy, new_node);
-end:
- /*
- * Only the flagging action indicated that we (and no other)
- * replaced the node from the hash table.
- */
- if (flagged) {
- assert(is_removed(rcu_dereference(old_node->p.next)));
- return 0;
- } else {
- return -ENOENT;
- }
+
+ assert(is_removed(rcu_dereference(old_node->p.next)));
+ return 0;
}
+/*
+ * A non-NULL unique_ret pointer uses the "add unique" (or uniquify) add
+ * mode. A NULL unique_ret allows creation of duplicate keys.
+ */
static
-struct cds_lfht_node *_cds_lfht_add(struct cds_lfht *ht,
- unsigned long size,
- struct cds_lfht_node *node,
- enum add_mode mode, int dummy)
+void _cds_lfht_add(struct cds_lfht *ht,
+ unsigned long size,
+ struct cds_lfht_node *node,
+ struct cds_lfht_iter *unique_ret,
+ int dummy)
{
struct cds_lfht_node *iter_prev, *iter, *next, *new_node, *new_next,
- *dummy_node, *return_node;
+ *return_node;
struct _cds_lfht_node *lookup;
- unsigned long hash, index, order;
assert(!is_dummy(node));
assert(!is_removed(node));
- if (!size) {
- assert(dummy);
- node->p.next = flag_dummy(get_end());
- return node; /* Initial first add (head) */
- }
- hash = bit_reverse_ulong(node->p.reverse_hash);
+ lookup = lookup_bucket(ht, size, bit_reverse_ulong(node->p.reverse_hash));
for (;;) {
uint32_t chain_len = 0;
* iter_prev points to the non-removed node prior to the
* insert location.
*/
- index = hash & (size - 1);
- order = get_count_order_ulong(index + 1);
- lookup = &ht->t.tbl[order]->nodes[index & ((!order ? 0 : (1UL << (order - 1))) - 1)];
iter_prev = (struct cds_lfht_node *) lookup;
/* We can always skip the dummy node initially */
iter = rcu_dereference(iter_prev->p.next);
goto insert;
if (likely(clear_flag(iter)->p.reverse_hash > node->p.reverse_hash))
goto insert;
+
+ /* dummy node is the first node of the identical-hash-value chain */
+ if (dummy && clear_flag(iter)->p.reverse_hash == node->p.reverse_hash)
+ goto insert;
+
next = rcu_dereference(clear_flag(iter)->p.next);
if (unlikely(is_removed(next)))
goto gc_node;
- if ((mode == ADD_UNIQUE || mode == ADD_REPLACE)
+
+ /* uniquely add */
+ if (unique_ret
&& !is_dummy(next)
- && !ht->compare_fct(node->key, node->key_len,
- clear_flag(iter)->key,
- clear_flag(iter)->key_len)) {
- if (mode == ADD_UNIQUE)
- return clear_flag(iter);
- else /* mode == ADD_REPLACE */
- goto replace;
+ && clear_flag(iter)->p.reverse_hash == node->p.reverse_hash) {
+ struct cds_lfht_iter d_iter = { .node = node, .next = iter, };
+
+ /*
+ * uniquely adding inserts the node as the first
+ * node of the identical-hash-value node chain.
+ *
+ * This semantic ensures no duplicated keys
+ * should ever be observable in the table
+ * (including observe one node by one node
+ * by forward iterations)
+ */
+ cds_lfht_next_duplicate(ht, &d_iter);
+ if (!d_iter.node)
+ goto insert;
+
+ *unique_ret = d_iter;
+ return;
}
+
/* Only account for identical reverse hash once */
if (iter_prev->p.reverse_hash != clear_flag(iter)->p.reverse_hash
&& !is_dummy(next))
new_node) != iter) {
continue; /* retry */
} else {
- if (mode == ADD_REPLACE)
- return_node = NULL;
- else /* ADD_DEFAULT and ADD_UNIQUE */
- return_node = node;
- goto gc_end;
- }
-
- replace:
-
- if (!_cds_lfht_replace(ht, size, clear_flag(iter), next,
- node)) {
- return_node = clear_flag(iter);
- goto end; /* gc already done */
- } else {
- continue; /* retry */
+ return_node = node;
+ goto end;
}
gc_node:
(void) uatomic_cmpxchg(&iter_prev->p.next, iter, new_next);
/* retry */
}
-gc_end:
- /* Garbage collect logically removed nodes in the bucket */
- index = hash & (size - 1);
- order = get_count_order_ulong(index + 1);
- lookup = &ht->t.tbl[order]->nodes[index & (!order ? 0 : ((1UL << (order - 1)) - 1))];
- dummy_node = (struct cds_lfht_node *) lookup;
- _cds_lfht_gc_bucket(dummy_node, node);
end:
- return return_node;
+ if (unique_ret) {
+ unique_ret->node = return_node;
+ /* unique_ret->next left unset, never used. */
+ }
}
static
{
struct cds_lfht_node *dummy, *next, *old;
struct _cds_lfht_node *lookup;
- int flagged = 0;
- unsigned long hash, index, order;
if (!node) /* Return -ENOENT if asked to delete NULL node */
- goto end;
+ return -ENOENT;
/* logically delete the node */
assert(!is_dummy(node));
next = old;
if (unlikely(is_removed(next)))
- goto end;
+ return -ENOENT;
if (dummy_removal)
assert(is_dummy(next));
else
new_next = flag_removed(next);
old = uatomic_cmpxchg(&node->p.next, next, new_next);
} while (old != next);
-
/* We performed the (logical) deletion. */
- flagged = 1;
/*
* Ensure that the node is not visible to readers anymore: lookup for
* the node, and remove it (along with any other logically removed node)
* if found.
*/
- hash = bit_reverse_ulong(node->p.reverse_hash);
- assert(size > 0);
- index = hash & (size - 1);
- order = get_count_order_ulong(index + 1);
- lookup = &ht->t.tbl[order]->nodes[index & (!order ? 0 : ((1UL << (order - 1)) - 1))];
+ lookup = lookup_bucket(ht, size, bit_reverse_ulong(node->p.reverse_hash));
dummy = (struct cds_lfht_node *) lookup;
_cds_lfht_gc_bucket(dummy, node);
-end:
- /*
- * Only the flagging action indicated that we (and no other)
- * removed the node from the hash.
- */
- if (flagged) {
- assert(is_removed(rcu_dereference(node->p.next)));
- return 0;
- } else {
- return -ENOENT;
- }
+
+ assert(is_removed(rcu_dereference(node->p.next)));
+ return 0;
}
static
struct partition_resize_work *work;
int thread, ret;
unsigned long nr_threads;
- pthread_t *thread_id;
/*
* Note: nr_cpus_mask + 1 is always power of 2.
}
partition_len = len >> get_count_order_ulong(nr_threads);
work = calloc(nr_threads, sizeof(*work));
- thread_id = calloc(nr_threads, sizeof(*thread_id));
assert(work);
for (thread = 0; thread < nr_threads; thread++) {
work[thread].ht = ht;
work[thread].len = partition_len;
work[thread].start = thread * partition_len;
work[thread].fct = fct;
- ret = pthread_create(&thread_id[thread], ht->resize_attr,
+ ret = pthread_create(&(work[thread].thread_id), ht->resize_attr,
partition_resize_thread, &work[thread]);
assert(!ret);
}
for (thread = 0; thread < nr_threads; thread++) {
- ret = pthread_join(thread_id[thread], NULL);
+ ret = pthread_join(work[thread].thread_id, NULL);
assert(!ret);
}
free(work);
- free(thread_id);
}
/*
{
unsigned long j;
+ assert(i > ht->min_alloc_order);
ht->cds_lfht_rcu_read_lock();
for (j = start; j < start + len; j++) {
struct cds_lfht_node *new_node =
(struct cds_lfht_node *) &ht->t.tbl[i]->nodes[j];
dbg_printf("init populate: i %lu j %lu hash %lu\n",
- i, j, !i ? 0 : (1UL << (i - 1)) + j);
+ i, j, (1UL << (i - 1)) + j);
new_node->p.reverse_hash =
- bit_reverse_ulong(!i ? 0 : (1UL << (i - 1)) + j);
- (void) _cds_lfht_add(ht, !i ? 0 : (1UL << (i - 1)),
- new_node, ADD_DEFAULT, 1);
- if (CMM_LOAD_SHARED(ht->in_progress_destroy))
- break;
+ bit_reverse_ulong((1UL << (i - 1)) + j);
+ _cds_lfht_add(ht, 1UL << (i - 1),
+ new_node, NULL, 1);
}
ht->cds_lfht_rcu_read_unlock();
}
static
void init_table(struct cds_lfht *ht,
- unsigned long first_order, unsigned long len_order)
+ unsigned long first_order, unsigned long last_order)
{
- unsigned long i, end_order;
+ unsigned long i;
- dbg_printf("init table: first_order %lu end_order %lu\n",
- first_order, first_order + len_order);
- end_order = first_order + len_order;
- for (i = first_order; i < end_order; i++) {
+ dbg_printf("init table: first_order %lu last_order %lu\n",
+ first_order, last_order);
+ assert(first_order > ht->min_alloc_order);
+ for (i = first_order; i <= last_order; i++) {
unsigned long len;
- len = !i ? 1 : 1UL << (i - 1);
+ len = 1UL << (i - 1);
dbg_printf("init order %lu len: %lu\n", i, len);
/* Stop expand if the resize target changes under us */
- if (CMM_LOAD_SHARED(ht->t.resize_target) < (!i ? 1 : (1UL << i)))
+ if (CMM_LOAD_SHARED(ht->t.resize_target) < (1UL << i))
break;
- ht->t.tbl[i] = calloc(1, sizeof(struct rcu_level)
- + (len * sizeof(struct _cds_lfht_node)));
+ ht->t.tbl[i] = calloc(1, len * sizeof(struct _cds_lfht_node));
assert(ht->t.tbl[i]);
/*
* Update table size.
*/
cmm_smp_wmb(); /* populate data before RCU size */
- CMM_STORE_SHARED(ht->t.size, !i ? 1 : (1UL << i));
+ CMM_STORE_SHARED(ht->t.size, 1UL << i);
- dbg_printf("init new size: %lu\n", !i ? 1 : (1UL << i));
+ dbg_printf("init new size: %lu\n", 1UL << i);
if (CMM_LOAD_SHARED(ht->in_progress_destroy))
break;
}
{
unsigned long j;
+ assert(i > ht->min_alloc_order);
ht->cds_lfht_rcu_read_lock();
for (j = start; j < start + len; j++) {
struct cds_lfht_node *fini_node =
(struct cds_lfht_node *) &ht->t.tbl[i]->nodes[j];
dbg_printf("remove entry: i %lu j %lu hash %lu\n",
- i, j, !i ? 0 : (1UL << (i - 1)) + j);
+ i, j, (1UL << (i - 1)) + j);
fini_node->p.reverse_hash =
- bit_reverse_ulong(!i ? 0 : (1UL << (i - 1)) + j);
- (void) _cds_lfht_del(ht, !i ? 0 : (1UL << (i - 1)),
- fini_node, 1);
- if (CMM_LOAD_SHARED(ht->in_progress_destroy))
- break;
+ bit_reverse_ulong((1UL << (i - 1)) + j);
+ (void) _cds_lfht_del(ht, 1UL << (i - 1), fini_node, 1);
}
ht->cds_lfht_rcu_read_unlock();
}
static
void fini_table(struct cds_lfht *ht,
- unsigned long first_order, unsigned long len_order)
+ unsigned long first_order, unsigned long last_order)
{
- long i, end_order;
+ long i;
+ void *free_by_rcu = NULL;
- dbg_printf("fini table: first_order %lu end_order %lu\n",
- first_order, first_order + len_order);
- end_order = first_order + len_order;
- assert(first_order > 0);
- for (i = end_order - 1; i >= first_order; i--) {
+ dbg_printf("fini table: first_order %lu last_order %lu\n",
+ first_order, last_order);
+ assert(first_order > ht->min_alloc_order);
+ for (i = last_order; i >= first_order; i--) {
unsigned long len;
- len = !i ? 1 : 1UL << (i - 1);
+ len = 1UL << (i - 1);
dbg_printf("fini order %lu len: %lu\n", i, len);
/* Stop shrink if the resize target changes under us */
* return a logically removed node as insert position.
*/
ht->cds_lfht_synchronize_rcu();
+ if (free_by_rcu)
+ free(free_by_rcu);
/*
* Set "removed" flag in dummy nodes about to be removed.
*/
remove_table(ht, i, len);
- ht->cds_lfht_call_rcu(&ht->t.tbl[i]->head, cds_lfht_free_level);
+ free_by_rcu = ht->t.tbl[i];
dbg_printf("fini new size: %lu\n", 1UL << i);
if (CMM_LOAD_SHARED(ht->in_progress_destroy))
break;
}
+
+ if (free_by_rcu) {
+ ht->cds_lfht_synchronize_rcu();
+ free(free_by_rcu);
+ }
+}
+
+static
+void cds_lfht_create_dummy(struct cds_lfht *ht, unsigned long size)
+{
+ struct _cds_lfht_node *prev, *node;
+ unsigned long order, len, i, j;
+
+ ht->t.tbl[0] = calloc(1, ht->min_alloc_size * sizeof(struct _cds_lfht_node));
+ assert(ht->t.tbl[0]);
+
+ dbg_printf("create dummy: order %lu index %lu hash %lu\n", 0, 0, 0);
+ ht->t.tbl[0]->nodes[0].next = flag_dummy(get_end());
+ ht->t.tbl[0]->nodes[0].reverse_hash = 0;
+
+ for (order = 1; order < get_count_order_ulong(size) + 1; order++) {
+ len = 1UL << (order - 1);
+ if (order <= ht->min_alloc_order) {
+ ht->t.tbl[order] = (struct rcu_level *) (ht->t.tbl[0]->nodes + len);
+ } else {
+ ht->t.tbl[order] = calloc(1, len * sizeof(struct _cds_lfht_node));
+ assert(ht->t.tbl[order]);
+ }
+
+ i = 0;
+ prev = ht->t.tbl[i]->nodes;
+ for (j = 0; j < len; j++) {
+ if (j & (j - 1)) { /* Between power of 2 */
+ prev++;
+ } else if (j) { /* At each power of 2 */
+ i++;
+ prev = ht->t.tbl[i]->nodes;
+ }
+
+ node = &ht->t.tbl[order]->nodes[j];
+ dbg_printf("create dummy: order %lu index %lu hash %lu\n",
+ order, j, j + len);
+ node->next = prev->next;
+ assert(is_dummy(node->next));
+ node->reverse_hash = bit_reverse_ulong(j + len);
+ prev->next = flag_dummy((struct cds_lfht_node *)node);
+ }
+ }
}
struct cds_lfht *_cds_lfht_new(cds_lfht_hash_fct hash_fct,
cds_lfht_compare_fct compare_fct,
unsigned long hash_seed,
unsigned long init_size,
+ unsigned long min_alloc_size,
int flags,
void (*cds_lfht_call_rcu)(struct rcu_head *head,
void (*func)(struct rcu_head *head)),
struct cds_lfht *ht;
unsigned long order;
+ /* min_alloc_size must be power of two */
+ if (!min_alloc_size || (min_alloc_size & (min_alloc_size - 1)))
+ return NULL;
/* init_size must be power of two */
- if (init_size && (init_size & (init_size - 1)))
+ if (!init_size || (init_size & (init_size - 1)))
return NULL;
+ min_alloc_size = max(min_alloc_size, MIN_TABLE_SIZE);
+ init_size = max(init_size, min_alloc_size);
ht = calloc(1, sizeof(struct cds_lfht));
assert(ht);
+ ht->flags = flags;
ht->hash_fct = hash_fct;
ht->compare_fct = compare_fct;
ht->hash_seed = hash_seed;
ht->cds_lfht_rcu_register_thread = cds_lfht_rcu_register_thread;
ht->cds_lfht_rcu_unregister_thread = cds_lfht_rcu_unregister_thread;
ht->resize_attr = attr;
- ht->percpu_count = alloc_per_cpu_items_count();
+ alloc_split_items_count(ht);
/* this mutex should not nest in read-side C.S. */
pthread_mutex_init(&ht->resize_mutex, NULL);
- order = get_count_order_ulong(max(init_size, MIN_TABLE_SIZE)) + 1;
- ht->flags = flags;
- ht->cds_lfht_rcu_thread_offline();
- pthread_mutex_lock(&ht->resize_mutex);
- ht->t.resize_target = 1UL << (order - 1);
- init_table(ht, 0, order);
- pthread_mutex_unlock(&ht->resize_mutex);
- ht->cds_lfht_rcu_thread_online();
+ order = get_count_order_ulong(init_size);
+ ht->t.resize_target = 1UL << order;
+ ht->min_alloc_size = min_alloc_size;
+ ht->min_alloc_order = get_count_order_ulong(min_alloc_size);
+ cds_lfht_create_dummy(ht, 1UL << order);
+ ht->t.size = 1UL << order;
return ht;
}
{
struct cds_lfht_node *node, *next, *dummy_node;
struct _cds_lfht_node *lookup;
- unsigned long hash, reverse_hash, index, order, size;
+ unsigned long hash, reverse_hash, size;
hash = ht->hash_fct(key, key_len, ht->hash_seed);
reverse_hash = bit_reverse_ulong(hash);
size = rcu_dereference(ht->t.size);
- index = hash & (size - 1);
- order = get_count_order_ulong(index + 1);
- lookup = &ht->t.tbl[order]->nodes[index & (!order ? 0 : ((1UL << (order - 1))) - 1)];
- dbg_printf("lookup hash %lu index %lu order %lu aridx %lu\n",
- hash, index, order, index & (!order ? 0 : ((1UL << (order - 1)) - 1)));
+ lookup = lookup_bucket(ht, size, hash);
dummy_node = (struct cds_lfht_node *) lookup;
/* We can always skip the dummy node initially */
node = rcu_dereference(dummy_node->p.next);
break;
}
next = rcu_dereference(node->p.next);
+ assert(node == clear_flag(node));
if (likely(!is_removed(next))
&& !is_dummy(next)
+ && node->p.reverse_hash == reverse_hash
&& likely(!ht->compare_fct(node->key, node->key_len, key, key_len))) {
break;
}
node->p.reverse_hash = bit_reverse_ulong((unsigned long) hash);
size = rcu_dereference(ht->t.size);
- (void) _cds_lfht_add(ht, size, node, ADD_DEFAULT, 0);
- ht_count_add(ht, size);
+ _cds_lfht_add(ht, size, node, NULL, 0);
+ ht_count_add(ht, size, hash);
}
struct cds_lfht_node *cds_lfht_add_unique(struct cds_lfht *ht,
struct cds_lfht_node *node)
{
unsigned long hash, size;
- struct cds_lfht_node *ret;
+ struct cds_lfht_iter iter;
hash = ht->hash_fct(node->key, node->key_len, ht->hash_seed);
node->p.reverse_hash = bit_reverse_ulong((unsigned long) hash);
size = rcu_dereference(ht->t.size);
- ret = _cds_lfht_add(ht, size, node, ADD_UNIQUE, 0);
- if (ret == node)
- ht_count_add(ht, size);
- return ret;
+ _cds_lfht_add(ht, size, node, &iter, 0);
+ if (iter.node == node)
+ ht_count_add(ht, size, hash);
+ return iter.node;
}
struct cds_lfht_node *cds_lfht_add_replace(struct cds_lfht *ht,
struct cds_lfht_node *node)
{
unsigned long hash, size;
- struct cds_lfht_node *ret;
+ struct cds_lfht_iter iter;
hash = ht->hash_fct(node->key, node->key_len, ht->hash_seed);
node->p.reverse_hash = bit_reverse_ulong((unsigned long) hash);
size = rcu_dereference(ht->t.size);
- ret = _cds_lfht_add(ht, size, node, ADD_REPLACE, 0);
- if (ret == NULL)
- ht_count_add(ht, size);
- return ret;
+ for (;;) {
+ _cds_lfht_add(ht, size, node, &iter, 0);
+ if (iter.node == node) {
+ ht_count_add(ht, size, hash);
+ return NULL;
+ }
+
+ if (!_cds_lfht_replace(ht, size, iter.node, iter.next, node))
+ return iter.node;
+ }
}
int cds_lfht_replace(struct cds_lfht *ht, struct cds_lfht_iter *old_iter,
int cds_lfht_del(struct cds_lfht *ht, struct cds_lfht_iter *iter)
{
- unsigned long size;
+ unsigned long size, hash;
int ret;
size = rcu_dereference(ht->t.size);
ret = _cds_lfht_del(ht, size, iter->node, 0);
- if (!ret)
- ht_count_del(ht, size);
+ if (!ret) {
+ hash = bit_reverse_ulong(iter->node->p.reverse_hash);
+ ht_count_del(ht, size, hash);
+ }
return ret;
}
bit_reverse_ulong(ht->t.tbl[order]->nodes[i].reverse_hash));
assert(is_dummy(ht->t.tbl[order]->nodes[i].next));
}
- poison_free(ht->t.tbl[order]);
+
+ if (order == ht->min_alloc_order)
+ poison_free(ht->t.tbl[0]);
+ else if (order > ht->min_alloc_order)
+ poison_free(ht->t.tbl[order]);
+ /* Nothing to delete for order < ht->min_alloc_order */
}
return 0;
}
int ret;
/* Wait for in-flight resize operations to complete */
- CMM_STORE_SHARED(ht->in_progress_destroy, 1);
+ _CMM_STORE_SHARED(ht->in_progress_destroy, 1);
+ cmm_smp_mb(); /* Store destroy before load resize */
while (uatomic_read(&ht->in_progress_resize))
poll(NULL, 0, 100); /* wait for 100ms */
ret = cds_lfht_delete_dummy(ht);
if (ret)
return ret;
- free_per_cpu_items_count(ht->percpu_count);
+ free_split_items_count(ht);
if (attr)
*attr = ht->resize_attr;
poison_free(ht);
unsigned long nr_dummy = 0;
*approx_before = 0;
- if (nr_cpus_mask >= 0) {
+ if (ht->split_count) {
int i;
- for (i = 0; i < nr_cpus_mask + 1; i++) {
- *approx_before += uatomic_read(&ht->percpu_count[i].add);
- *approx_before -= uatomic_read(&ht->percpu_count[i].del);
+ for (i = 0; i < split_count_mask + 1; i++) {
+ *approx_before += uatomic_read(&ht->split_count[i].add);
+ *approx_before -= uatomic_read(&ht->split_count[i].del);
}
}
} while (!is_end(node));
dbg_printf("number of dummy nodes: %lu\n", nr_dummy);
*approx_after = 0;
- if (nr_cpus_mask >= 0) {
+ if (ht->split_count) {
int i;
- for (i = 0; i < nr_cpus_mask + 1; i++) {
- *approx_after += uatomic_read(&ht->percpu_count[i].add);
- *approx_after -= uatomic_read(&ht->percpu_count[i].del);
+ for (i = 0; i < split_count_mask + 1; i++) {
+ *approx_after += uatomic_read(&ht->split_count[i].add);
+ *approx_after -= uatomic_read(&ht->split_count[i].del);
}
}
}
{
unsigned long old_order, new_order;
- old_order = get_count_order_ulong(old_size) + 1;
- new_order = get_count_order_ulong(new_size) + 1;
- printf("resize from %lu (order %lu) to %lu (order %lu) buckets\n",
- old_size, old_order, new_size, new_order);
+ old_order = get_count_order_ulong(old_size);
+ new_order = get_count_order_ulong(new_size);
+ dbg_printf("resize from %lu (order %lu) to %lu (order %lu) buckets\n",
+ old_size, old_order, new_size, new_order);
assert(new_size > old_size);
- init_table(ht, old_order, new_order - old_order);
+ init_table(ht, old_order + 1, new_order);
}
/* called with resize mutex held */
{
unsigned long old_order, new_order;
- new_size = max(new_size, MIN_TABLE_SIZE);
- old_order = get_count_order_ulong(old_size) + 1;
- new_order = get_count_order_ulong(new_size) + 1;
- printf("resize from %lu (order %lu) to %lu (order %lu) buckets\n",
- old_size, old_order, new_size, new_order);
+ new_size = max(new_size, ht->min_alloc_size);
+ old_order = get_count_order_ulong(old_size);
+ new_order = get_count_order_ulong(new_size);
+ dbg_printf("resize from %lu (order %lu) to %lu (order %lu) buckets\n",
+ old_size, old_order, new_size, new_order);
assert(new_size < old_size);
/* Remove and unlink all dummy nodes to remove. */
- fini_table(ht, new_order, old_order - new_order);
+ fini_table(ht, new_order + 1, old_order);
}
* Resize table, re-do if the target size has changed under us.
*/
do {
+ assert(uatomic_read(&ht->in_progress_resize));
+ if (CMM_LOAD_SHARED(ht->in_progress_destroy))
+ break;
ht->t.resize_initiated = 1;
old_size = ht->t.size;
new_size = CMM_LOAD_SHARED(ht->t.resize_target);
void resize_target_update_count(struct cds_lfht *ht,
unsigned long count)
{
- count = max(count, MIN_TABLE_SIZE);
+ count = max(count, ht->min_alloc_size);
uatomic_set(&ht->t.resize_target, count);
}
cmm_smp_mb();
if (!CMM_LOAD_SHARED(ht->t.resize_initiated) && size < target_size) {
uatomic_inc(&ht->in_progress_resize);
- cmm_smp_mb(); /* increment resize count before calling it */
+ cmm_smp_mb(); /* increment resize count before load destroy */
+ if (CMM_LOAD_SHARED(ht->in_progress_destroy)) {
+ uatomic_dec(&ht->in_progress_resize);
+ return;
+ }
work = malloc(sizeof(*work));
work->ht = ht;
ht->cds_lfht_call_rcu(&work->head, do_resize_cb);
}
}
-#if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF)
-
static
void cds_lfht_resize_lazy_count(struct cds_lfht *ht, unsigned long size,
unsigned long count)
cmm_smp_mb();
if (!CMM_LOAD_SHARED(ht->t.resize_initiated)) {
uatomic_inc(&ht->in_progress_resize);
- cmm_smp_mb(); /* increment resize count before calling it */
+ cmm_smp_mb(); /* increment resize count before load destroy */
+ if (CMM_LOAD_SHARED(ht->in_progress_destroy)) {
+ uatomic_dec(&ht->in_progress_resize);
+ return;
+ }
work = malloc(sizeof(*work));
work->ht = ht;
ht->cds_lfht_call_rcu(&work->head, do_resize_cb);
CMM_STORE_SHARED(ht->t.resize_initiated, 1);
}
}
-
-#endif
projects / lttng-tools.git / commitdiff
