From cd235703c0f59f24fe809f3a15c1fc30037aad09 Mon Sep 17 00:00:00 2001 From: Mathieu Desnoyers Date: Thu, 17 Sep 2015 12:48:41 -0400 Subject: [PATCH] Cleanup: remove duplicated implementation of rculfhash MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit lttng-tools features a duplicated copy of Userspace RCU rculfhash due to interaction issues between runas clone() and internal libc mutexes. Now that the runas implementation has been changed to use fork() and a worker process, we don't need this work-around anymore. Remove the duplicated rculfhash to lessen the maintenance burden. Signed-off-by: Mathieu Desnoyers Signed-off-by: Jérémie Galarneau --- src/common/hashtable/Makefile.am | 7 +- src/common/hashtable/hashtable.h | 3 +- src/common/hashtable/rculfhash-internal.h | 184 -- src/common/hashtable/rculfhash-mm-chunk.c | 99 - src/common/hashtable/rculfhash-mm-mmap.c | 162 -- src/common/hashtable/rculfhash-mm-order.c | 92 - src/common/hashtable/rculfhash.c | 2035 --------------------- src/common/hashtable/rculfhash.h | 480 ----- src/common/hashtable/urcu-flavor.h | 65 - 9 files changed, 2 insertions(+), 3125 deletions(-) delete mode 100644 src/common/hashtable/rculfhash-internal.h delete mode 100644 src/common/hashtable/rculfhash-mm-chunk.c delete mode 100644 src/common/hashtable/rculfhash-mm-mmap.c delete mode 100644 src/common/hashtable/rculfhash-mm-order.c delete mode 100644 src/common/hashtable/rculfhash.c delete mode 100644 src/common/hashtable/rculfhash.h delete mode 100644 src/common/hashtable/urcu-flavor.h diff --git a/src/common/hashtable/Makefile.am b/src/common/hashtable/Makefile.am index 021f01c79..765f64953 100644 --- a/src/common/hashtable/Makefile.am +++ b/src/common/hashtable/Makefile.am @@ -4,11 +4,6 @@ noinst_LTLIBRARIES = libhashtable.la libhashtable_la_SOURCES = hashtable.c hashtable.h \ utils.c utils.h \ - rculfhash-internal.h urcu-flavor.h \ - rculfhash.h rculfhash.c \ - rculfhash-mm-chunk.c \ - rculfhash-mm-mmap.c \ - rculfhash-mm-order.c \ hashtable-symbols.h -libhashtable_la_LIBADD = -lurcu-common -lurcu +libhashtable_la_LIBADD = -lurcu-common -lurcu -lurcu-cds diff --git a/src/common/hashtable/hashtable.h b/src/common/hashtable/hashtable.h index 05c174228..a3d41d94d 100644 --- a/src/common/hashtable/hashtable.h +++ b/src/common/hashtable/hashtable.h @@ -21,9 +21,8 @@ #include #include -#include "rculfhash.h" -#include "rculfhash-internal.h" #include +#include extern unsigned long lttng_ht_seed; diff --git a/src/common/hashtable/rculfhash-internal.h b/src/common/hashtable/rculfhash-internal.h deleted file mode 100644 index e3a59ba17..000000000 --- a/src/common/hashtable/rculfhash-internal.h +++ /dev/null @@ -1,184 +0,0 @@ -#ifndef URCU_RCULFHASH_INTERNAL_H -#define URCU_RCULFHASH_INTERNAL_H - -/* - * urcu/rculfhash-internal.h - * - * Internal header for Lock-Free RCU Hash Table - * - * Copyright 2011 - Mathieu Desnoyers - * Copyright 2011 - Lai Jiangshan - * - * 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 - */ - -#include - -#include "rculfhash.h" - -#ifdef DEBUG -#define dbg_printf(fmt, args...) printf("[debug rculfhash] " fmt, ## args) -#else -#define dbg_printf(fmt, args...) \ -do { \ - /* do nothing but check printf format */ \ - if (0) \ - printf("[debug rculfhash] " fmt, ## args); \ -} while (0) -#endif - -#if (CAA_BITS_PER_LONG == 32) -#define MAX_TABLE_ORDER 32 -#else -#define MAX_TABLE_ORDER 64 -#endif - -#define MAX_CHUNK_TABLE (1UL << 10) - -#ifndef min -#define min(a, b) ((a) < (b) ? (a) : (b)) -#endif - -#ifndef max -#define max(a, b) ((a) > (b) ? (a) : (b)) -#endif - -struct ht_items_count; - -/* - * 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. - * - * The fields used in fast-paths are placed near the end of the - * structure, because we need to have a variable-sized union to contain - * the mm plugin fields, which are used in the fast path. - */ -struct cds_lfht { - /* Initial configuration items */ - unsigned long max_nr_buckets; - const struct cds_lfht_mm_type *mm; /* memory management plugin */ - const struct rcu_flavor_struct *flavor; /* RCU flavor */ - - long count; /* global approximate item count */ - - /* - * We need to put the work threads offline (QSBR) when taking this - * mutex, because we use synchronize_rcu within this mutex critical - * section, which waits on read-side critical sections, and could - * therefore cause grace-period deadlock if we hold off RCU G.P. - * completion. - */ - pthread_mutex_t resize_mutex; /* resize mutex: add/del mutex */ - pthread_attr_t *resize_attr; /* Resize threads attributes */ - unsigned int in_progress_resize, in_progress_destroy; - unsigned long resize_target; - int resize_initiated; - - /* - * Variables needed for add and remove fast-paths. - */ - int flags; - unsigned long min_alloc_buckets_order; - unsigned long min_nr_alloc_buckets; - struct ht_items_count *split_count; /* split item count */ - - /* - * Variables needed for the lookup, add and remove fast-paths. - */ - unsigned long size; /* always a power of 2, shared (RCU) */ - /* - * bucket_at pointer is kept here to skip the extra level of - * dereference needed to get to "mm" (this is a fast-path). - */ - struct cds_lfht_node *(*bucket_at)(struct cds_lfht *ht, - unsigned long index); - /* - * Dynamic length "tbl_chunk" needs to be at the end of - * cds_lfht. - */ - union { - /* - * Contains the per order-index-level bucket node table. - * The size of each bucket node table is half the number - * of hashes contained in this order (except for order 0). - * The minimum allocation buckets size parameter allows - * combining the bucket node arrays of the lowermost - * levels to improve cache locality for small index orders. - */ - struct cds_lfht_node *tbl_order[MAX_TABLE_ORDER]; - - /* - * Contains the bucket node chunks. The size of each - * bucket node chunk is ->min_alloc_size (we avoid to - * allocate chunks with different size). Chunks improve - * cache locality for small index orders, and are more - * friendly with environments where allocation of large - * contiguous memory areas is challenging due to memory - * fragmentation concerns or inability to use virtual - * memory addressing. - */ - struct cds_lfht_node *tbl_chunk[0]; - - /* - * Memory mapping with room for all possible buckets. - * Their memory is allocated when needed. - */ - struct cds_lfht_node *tbl_mmap; - }; - /* - * End of variables needed for the lookup, add and remove - * fast-paths. - */ -}; - -extern unsigned int cds_lfht_fls_ulong(unsigned long x); -extern int cds_lfht_get_count_order_ulong(unsigned long x); - -#ifdef POISON_FREE -#define poison_free(ptr) \ - do { \ - if (ptr) { \ - memset(ptr, 0x42, sizeof(*(ptr))); \ - free(ptr); \ - } \ - } while (0) -#else -#define poison_free(ptr) free(ptr) -#endif - -static inline -struct cds_lfht *__default_alloc_cds_lfht( - const struct cds_lfht_mm_type *mm, - unsigned long cds_lfht_size, - unsigned long min_nr_alloc_buckets, - unsigned long max_nr_buckets) -{ - struct cds_lfht *ht; - - ht = calloc(1, cds_lfht_size); - assert(ht); - - ht->mm = mm; - ht->bucket_at = mm->bucket_at; - ht->min_nr_alloc_buckets = min_nr_alloc_buckets; - ht->min_alloc_buckets_order = - cds_lfht_get_count_order_ulong(min_nr_alloc_buckets); - ht->max_nr_buckets = max_nr_buckets; - - return ht; -} - -#endif /* _URCU_RCULFHASH_INTERNAL_H */ diff --git a/src/common/hashtable/rculfhash-mm-chunk.c b/src/common/hashtable/rculfhash-mm-chunk.c deleted file mode 100644 index 2e4e049dd..000000000 --- a/src/common/hashtable/rculfhash-mm-chunk.c +++ /dev/null @@ -1,99 +0,0 @@ -/* - * rculfhash-mm-chunk.c - * - * Chunk based memory management for Lock-Free RCU Hash Table - * - * Copyright 2011 - Lai Jiangshan - * - * 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 _GNU_SOURCE -#define _LGPL_SOURCE -#include -#include "rculfhash-internal.h" - -static -void cds_lfht_alloc_bucket_table(struct cds_lfht *ht, unsigned long order) -{ - if (order == 0) { - ht->tbl_chunk[0] = calloc(ht->min_nr_alloc_buckets, - sizeof(struct cds_lfht_node)); - assert(ht->tbl_chunk[0]); - } else if (order > ht->min_alloc_buckets_order) { - unsigned long i, len = 1UL << (order - 1 - ht->min_alloc_buckets_order); - - for (i = len; i < 2 * len; i++) { - ht->tbl_chunk[i] = calloc(ht->min_nr_alloc_buckets, - sizeof(struct cds_lfht_node)); - assert(ht->tbl_chunk[i]); - } - } - /* Nothing to do for 0 < order && order <= ht->min_alloc_buckets_order */ -} - -/* - * cds_lfht_free_bucket_table() should be called with decreasing order. - * When cds_lfht_free_bucket_table(0) is called, it means the whole - * lfht is destroyed. - */ -static -void cds_lfht_free_bucket_table(struct cds_lfht *ht, unsigned long order) -{ - if (order == 0) - poison_free(ht->tbl_chunk[0]); - else if (order > ht->min_alloc_buckets_order) { - unsigned long i, len = 1UL << (order - 1 - ht->min_alloc_buckets_order); - - for (i = len; i < 2 * len; i++) - poison_free(ht->tbl_chunk[i]); - } - /* Nothing to do for 0 < order && order <= ht->min_alloc_buckets_order */ -} - -static -struct cds_lfht_node *bucket_at(struct cds_lfht *ht, unsigned long index) -{ - unsigned long chunk, offset; - - chunk = index >> ht->min_alloc_buckets_order; - offset = index & (ht->min_nr_alloc_buckets - 1); - return &ht->tbl_chunk[chunk][offset]; -} - -static -struct cds_lfht *alloc_cds_lfht(unsigned long min_nr_alloc_buckets, - unsigned long max_nr_buckets) -{ - unsigned long nr_chunks, cds_lfht_size; - - min_nr_alloc_buckets = max(min_nr_alloc_buckets, - max_nr_buckets / MAX_CHUNK_TABLE); - nr_chunks = max_nr_buckets / min_nr_alloc_buckets; - cds_lfht_size = offsetof(struct cds_lfht, tbl_chunk) + - sizeof(struct cds_lfht_node *) * nr_chunks; - cds_lfht_size = max(cds_lfht_size, sizeof(struct cds_lfht)); - - return __default_alloc_cds_lfht( - &cds_lfht_mm_chunk, cds_lfht_size, - min_nr_alloc_buckets, max_nr_buckets); -} - -const struct cds_lfht_mm_type cds_lfht_mm_chunk = { - .alloc_cds_lfht = alloc_cds_lfht, - .alloc_bucket_table = cds_lfht_alloc_bucket_table, - .free_bucket_table = cds_lfht_free_bucket_table, - .bucket_at = bucket_at, -}; diff --git a/src/common/hashtable/rculfhash-mm-mmap.c b/src/common/hashtable/rculfhash-mm-mmap.c deleted file mode 100644 index cd415dbde..000000000 --- a/src/common/hashtable/rculfhash-mm-mmap.c +++ /dev/null @@ -1,162 +0,0 @@ -/* - * rculfhash-mm-mmap.c - * - * mmap/reservation based memory management for Lock-Free RCU Hash Table - * - * Copyright 2011 - Lai Jiangshan - * - * 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 _GNU_SOURCE -#define _LGPL_SOURCE -#include -#include -#include "rculfhash-internal.h" - -#ifndef MAP_ANONYMOUS -#define MAP_ANONYMOUS MAP_ANON -#endif - -/* reserve inaccessible memory space without allocation any memory */ -static void *memory_map(size_t length) -{ - void *ret = mmap(NULL, length, PROT_NONE, - MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); - - assert(ret != MAP_FAILED); - return ret; -} - -static void memory_unmap(void *ptr, size_t length) -{ - int ret __attribute__((unused)); - - ret = munmap(ptr, length); - - assert(ret == 0); -} - -static void memory_populate(void *ptr, size_t length) -{ - void *ret __attribute__((unused)); - - ret = mmap(ptr, length, PROT_READ | PROT_WRITE, - MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); - - assert(ret == ptr); -} - -/* - * Discard garbage memory and avoid system save it when try to swap it out. - * Make it still reserved, inaccessible. - */ -static void memory_discard(void *ptr, size_t length) -{ - void *ret __attribute__((unused)); - - ret = mmap(ptr, length, PROT_NONE, - MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); - - assert(ret == ptr); -} - -static -void cds_lfht_alloc_bucket_table(struct cds_lfht *ht, unsigned long order) -{ - if (order == 0) { - if (ht->min_nr_alloc_buckets == ht->max_nr_buckets) { - /* small table */ - ht->tbl_mmap = calloc(ht->max_nr_buckets, - sizeof(*ht->tbl_mmap)); - assert(ht->tbl_mmap); - return; - } - /* large table */ - ht->tbl_mmap = memory_map(ht->max_nr_buckets - * sizeof(*ht->tbl_mmap)); - memory_populate(ht->tbl_mmap, - ht->min_nr_alloc_buckets * sizeof(*ht->tbl_mmap)); - } else if (order > ht->min_alloc_buckets_order) { - /* large table */ - unsigned long len = 1UL << (order - 1); - - assert(ht->min_nr_alloc_buckets < ht->max_nr_buckets); - memory_populate(ht->tbl_mmap + len, - len * sizeof(*ht->tbl_mmap)); - } - /* Nothing to do for 0 < order && order <= ht->min_alloc_buckets_order */ -} - -/* - * cds_lfht_free_bucket_table() should be called with decreasing order. - * When cds_lfht_free_bucket_table(0) is called, it means the whole - * lfht is destroyed. - */ -static -void cds_lfht_free_bucket_table(struct cds_lfht *ht, unsigned long order) -{ - if (order == 0) { - if (ht->min_nr_alloc_buckets == ht->max_nr_buckets) { - /* small table */ - poison_free(ht->tbl_mmap); - return; - } - /* large table */ - memory_unmap(ht->tbl_mmap, - ht->max_nr_buckets * sizeof(*ht->tbl_mmap)); - } else if (order > ht->min_alloc_buckets_order) { - /* large table */ - unsigned long len = 1UL << (order - 1); - - assert(ht->min_nr_alloc_buckets < ht->max_nr_buckets); - memory_discard(ht->tbl_mmap + len, len * sizeof(*ht->tbl_mmap)); - } - /* Nothing to do for 0 < order && order <= ht->min_alloc_buckets_order */ -} - -static -struct cds_lfht_node *bucket_at(struct cds_lfht *ht, unsigned long index) -{ - return &ht->tbl_mmap[index]; -} - -static -struct cds_lfht *alloc_cds_lfht(unsigned long min_nr_alloc_buckets, - unsigned long max_nr_buckets) -{ - unsigned long page_bucket_size; - - page_bucket_size = getpagesize() / sizeof(struct cds_lfht_node); - if (max_nr_buckets <= page_bucket_size) { - /* small table */ - min_nr_alloc_buckets = max_nr_buckets; - } else { - /* large table */ - min_nr_alloc_buckets = max(min_nr_alloc_buckets, - page_bucket_size); - } - - return __default_alloc_cds_lfht( - &cds_lfht_mm_mmap, sizeof(struct cds_lfht), - min_nr_alloc_buckets, max_nr_buckets); -} - -const struct cds_lfht_mm_type cds_lfht_mm_mmap = { - .alloc_cds_lfht = alloc_cds_lfht, - .alloc_bucket_table = cds_lfht_alloc_bucket_table, - .free_bucket_table = cds_lfht_free_bucket_table, - .bucket_at = bucket_at, -}; diff --git a/src/common/hashtable/rculfhash-mm-order.c b/src/common/hashtable/rculfhash-mm-order.c deleted file mode 100644 index 0ce98d7a9..000000000 --- a/src/common/hashtable/rculfhash-mm-order.c +++ /dev/null @@ -1,92 +0,0 @@ -/* - * rculfhash-mm-order.c - * - * Order based memory management for Lock-Free RCU Hash Table - * - * Copyright 2011 - Mathieu Desnoyers - * Copyright 2011 - Lai Jiangshan - * - * 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 _GNU_SOURCE -#define _LGPL_SOURCE -#include "rculfhash-internal.h" - -static -void cds_lfht_alloc_bucket_table(struct cds_lfht *ht, unsigned long order) -{ - if (order == 0) { - ht->tbl_order[0] = calloc(ht->min_nr_alloc_buckets, - sizeof(struct cds_lfht_node)); - assert(ht->tbl_order[0]); - } else if (order > ht->min_alloc_buckets_order) { - ht->tbl_order[order] = calloc(1UL << (order -1), - sizeof(struct cds_lfht_node)); - assert(ht->tbl_order[order]); - } - /* Nothing to do for 0 < order && order <= ht->min_alloc_buckets_order */ -} - -/* - * cds_lfht_free_bucket_table() should be called with decreasing order. - * When cds_lfht_free_bucket_table(0) is called, it means the whole - * lfht is destroyed. - */ -static -void cds_lfht_free_bucket_table(struct cds_lfht *ht, unsigned long order) -{ - if (order == 0) - poison_free(ht->tbl_order[0]); - else if (order > ht->min_alloc_buckets_order) - poison_free(ht->tbl_order[order]); - /* Nothing to do for 0 < order && order <= ht->min_alloc_buckets_order */ -} - -static -struct cds_lfht_node *bucket_at(struct cds_lfht *ht, unsigned long index) -{ - unsigned long order; - - if (index < ht->min_nr_alloc_buckets) { - dbg_printf("bucket index %lu order 0 aridx 0\n", index); - return &ht->tbl_order[0][index]; - } - /* - * equivalent to cds_lfht_get_count_order_ulong(index + 1), but - * optimizes away the non-existing 0 special-case for - * cds_lfht_get_count_order_ulong. - */ - order = cds_lfht_fls_ulong(index); - dbg_printf("bucket index %lu order %lu aridx %lu\n", - index, order, index & ((1UL << (order - 1)) - 1)); - return &ht->tbl_order[order][index & ((1UL << (order - 1)) - 1)]; -} - -static -struct cds_lfht *alloc_cds_lfht(unsigned long min_nr_alloc_buckets, - unsigned long max_nr_buckets) -{ - return __default_alloc_cds_lfht( - &cds_lfht_mm_order, sizeof(struct cds_lfht), - min_nr_alloc_buckets, max_nr_buckets); -} - -const struct cds_lfht_mm_type cds_lfht_mm_order = { - .alloc_cds_lfht = alloc_cds_lfht, - .alloc_bucket_table = cds_lfht_alloc_bucket_table, - .free_bucket_table = cds_lfht_free_bucket_table, - .bucket_at = bucket_at, -}; diff --git a/src/common/hashtable/rculfhash.c b/src/common/hashtable/rculfhash.c deleted file mode 100644 index 9baf40798..000000000 --- a/src/common/hashtable/rculfhash.c +++ /dev/null @@ -1,2035 +0,0 @@ -/* - * rculfhash.c - * - * Userspace RCU library - Lock-Free Resizable RCU Hash Table - * - * Copyright 2010-2011 - Mathieu Desnoyers - * Copyright 2011 - Lai Jiangshan - * - * 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 - */ - -/* - * Based on the following articles: - * - Ori Shalev and Nir Shavit. Split-ordered lists: Lock-free - * extensible hash tables. J. ACM 53, 3 (May 2006), 379-405. - * - Michael, M. M. High performance dynamic lock-free hash tables - * and list-based sets. In Proceedings of the fourteenth annual ACM - * symposium on Parallel algorithms and architectures, ACM Press, - * (2002), 73-82. - * - * Some specificities of this Lock-Free Resizable RCU Hash Table - * implementation: - * - * - RCU read-side critical section allows readers to perform hash - * table lookups, as well as traversals, and use the returned objects - * safely by allowing memory reclaim to take place only after a grace - * period. - * - Add and remove operations are lock-free, and do not need to - * allocate memory. They need to be executed within RCU read-side - * critical section to ensure the objects they read are valid and to - * deal with the cmpxchg ABA problem. - * - add and add_unique operations are supported. add_unique checks if - * the node key already exists in the hash table. It ensures not to - * populate a duplicate key if the node key already exists in the hash - * table. - * - The resize operation executes concurrently with - * add/add_unique/add_replace/remove/lookup/traversal. - * - Hash table nodes are contained within a split-ordered list. This - * list is ordered by incrementing reversed-bits-hash value. - * - An index of bucket nodes is kept. These bucket nodes are the hash - * table "buckets". These buckets are internal nodes that allow to - * perform a fast hash lookup, similarly to a skip list. These - * buckets are chained together in the split-ordered list, which - * allows recursive expansion by inserting new buckets between the - * existing buckets. The split-ordered list allows adding new buckets - * between existing buckets as the table needs to grow. - * - The resize operation for small tables only allows expanding the - * hash table. It is triggered automatically by detecting long chains - * in the add operation. - * - The resize operation for larger tables (and available through an - * API) allows both expanding and shrinking the hash table. - * - 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. - * - Resize operations are protected by a mutex. - * - The removal operation is split in two parts: first, a "removed" - * flag is set in the next pointer within the node to remove. Then, - * a "garbage collection" is performed in the bucket containing the - * removed node (from the start of the bucket up to the removed node). - * All encountered nodes with "removed" flag set in their next - * pointers are removed from the linked-list. If the cmpxchg used for - * removal fails (due to concurrent garbage-collection or concurrent - * add), we retry from the beginning of the bucket. This ensures that - * the node with "removed" flag set is removed from the hash table - * (not visible to lookups anymore) before the RCU read-side critical - * section held across removal ends. Furthermore, this ensures that - * the node with "removed" flag set is removed from the linked-list - * before its memory is reclaimed. After setting the "removal" flag, - * only the thread which removal is the first to set the "removal - * owner" flag (with an xchg) into a node's next pointer is considered - * to have succeeded its removal (and thus owns the node to reclaim). - * Because we garbage-collect starting from an invariant node (the - * start-of-bucket bucket node) up to the "removed" node (or find a - * reverse-hash that is higher), we are sure that a successful - * traversal of the chain leads to a chain that is present in the - * linked-list (the start node is never removed) and that it does not - * contain the "removed" node anymore, even if concurrent delete/add - * operations are changing the structure of the list concurrently. - * - The add operations perform garbage collection of buckets if they - * encounter nodes with removed flag set in the bucket where they want - * to add their new node. This ensures lock-freedom of add operation by - * helping the remover unlink nodes from the list rather than to wait - * for it do to so. - * - There are three memory backends for the hash table buckets: the - * "order table", the "chunks", and the "mmap". - * - These bucket containers contain a compact version of the hash table - * nodes. - * - The RCU "order table": - * - has a first level table indexed by log2(hash index) which is - * copied and expanded by the resize operation. This order table - * allows finding the "bucket node" tables. - * - There is one bucket node table per hash index order. The size of - * each bucket node table is half the number of hashes contained in - * this order (except for order 0). - * - The RCU "chunks" is best suited for close interaction with a page - * allocator. It uses a linear array as index to "chunks" containing - * each the same number of buckets. - * - The RCU "mmap" memory backend uses a single memory map to hold - * all buckets. - * - synchronize_rcu is used to garbage-collect the old bucket node table. - * - * Ordering Guarantees: - * - * To discuss these guarantees, we first define "read" operation as any - * of the the basic cds_lfht_lookup, cds_lfht_next_duplicate, - * cds_lfht_first, cds_lfht_next operation, as well as - * cds_lfht_add_unique (failure). - * - * We define "read traversal" operation as any of the following - * group of operations - * - cds_lfht_lookup followed by iteration with cds_lfht_next_duplicate - * (and/or cds_lfht_next, although less common). - * - cds_lfht_add_unique (failure) followed by iteration with - * cds_lfht_next_duplicate (and/or cds_lfht_next, although less - * common). - * - cds_lfht_first followed iteration with cds_lfht_next (and/or - * cds_lfht_next_duplicate, although less common). - * - * We define "write" operations as any of cds_lfht_add, - * cds_lfht_add_unique (success), cds_lfht_add_replace, cds_lfht_del. - * - * When cds_lfht_add_unique succeeds (returns the node passed as - * parameter), it acts as a "write" operation. When cds_lfht_add_unique - * fails (returns a node different from the one passed as parameter), it - * acts as a "read" operation. A cds_lfht_add_unique failure is a - * cds_lfht_lookup "read" operation, therefore, any ordering guarantee - * referring to "lookup" imply any of "lookup" or cds_lfht_add_unique - * (failure). - * - * We define "prior" and "later" node as nodes observable by reads and - * read traversals respectively before and after a write or sequence of - * write operations. - * - * Hash-table operations are often cascaded, for example, the pointer - * returned by a cds_lfht_lookup() might be passed to a cds_lfht_next(), - * whose return value might in turn be passed to another hash-table - * operation. This entire cascaded series of operations must be enclosed - * by a pair of matching rcu_read_lock() and rcu_read_unlock() - * operations. - * - * The following ordering guarantees are offered by this hash table: - * - * A.1) "read" after "write": if there is ordering between a write and a - * later read, then the read is guaranteed to see the write or some - * later write. - * A.2) "read traversal" after "write": given that there is dependency - * ordering between reads in a "read traversal", if there is - * ordering between a write and the first read of the traversal, - * then the "read traversal" is guaranteed to see the write or - * some later write. - * B.1) "write" after "read": if there is ordering between a read and a - * later write, then the read will never see the write. - * B.2) "write" after "read traversal": given that there is dependency - * ordering between reads in a "read traversal", if there is - * ordering between the last read of the traversal and a later - * write, then the "read traversal" will never see the write. - * C) "write" while "read traversal": if a write occurs during a "read - * traversal", the traversal may, or may not, see the write. - * D.1) "write" after "write": if there is ordering between a write and - * a later write, then the later write is guaranteed to see the - * effects of the first write. - * D.2) Concurrent "write" pairs: The system will assign an arbitrary - * order to any pair of concurrent conflicting writes. - * Non-conflicting writes (for example, to different keys) are - * unordered. - * E) If a grace period separates a "del" or "replace" operation - * and a subsequent operation, then that subsequent operation is - * guaranteed not to see the removed item. - * F) Uniqueness guarantee: given a hash table that does not contain - * duplicate items for a given key, there will only be one item in - * the hash table after an arbitrary sequence of add_unique and/or - * add_replace operations. Note, however, that a pair of - * concurrent read operations might well access two different items - * with that key. - * G.1) If a pair of lookups for a given key are ordered (e.g. by a - * memory barrier), then the second lookup will return the same - * node as the previous lookup, or some later node. - * G.2) A "read traversal" that starts after the end of a prior "read - * traversal" (ordered by memory barriers) is guaranteed to see the - * same nodes as the previous traversal, or some later nodes. - * G.3) Concurrent "read" pairs: concurrent reads are unordered. For - * example, if a pair of reads to the same key run concurrently - * with an insertion of that same key, the reads remain unordered - * regardless of their return values. In other words, you cannot - * rely on the values returned by the reads to deduce ordering. - * - * Progress guarantees: - * - * * Reads are wait-free. These operations always move forward in the - * hash table linked list, and this list has no loop. - * * Writes are lock-free. Any retry loop performed by a write operation - * is triggered by progress made within another update operation. - * - * Bucket node tables: - * - * hash table hash table the last all bucket node tables - * order size bucket 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 bucket 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 bucket node table - * shrink hash table from order 6 to 5: fini the index=6 bucket node table - * - * A bit of ascii art explanation: - * - * The order index is the off-by-one compared to the actual power of 2 - * because we use index 0 to deal with the 0 special-case. - * - * This shows the nodes for a small table ordered by reversed bits: - * - * bits reverse - * 0 000 000 - * 4 100 001 - * 2 010 010 - * 6 110 011 - * 1 001 100 - * 5 101 101 - * 3 011 110 - * 7 111 111 - * - * This shows the nodes in order of non-reversed bits, linked by - * reversed-bit order. - * - * order bits reverse - * 0 0 000 000 - * 1 | 1 001 100 <- - * 2 | | 2 010 010 <- | - * | | | 3 011 110 | <- | - * 3 -> | | | 4 100 001 | | - * -> | | 5 101 101 | - * -> | 6 110 011 - * -> 7 111 111 - */ - -#define _LGPL_SOURCE -#define _GNU_SOURCE -#include -#include -#include -#include -#include -#include -#include - -#include "config.h" -#include -#include -#include -#include -#include -#include -#include - -#include "rculfhash.h" -#include "rculfhash-internal.h" -#include "urcu-flavor.h" - -#include - -/* - * 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 - -/* - * Define the minimum table size. - */ -#define MIN_TABLE_ORDER 0 -#define MIN_TABLE_SIZE (1UL << MIN_TABLE_ORDER) - -/* - * Minimum number of bucket nodes to touch per thread to parallelize grow/shrink. - */ -#define MIN_PARTITION_PER_THREAD_ORDER 12 -#define MIN_PARTITION_PER_THREAD (1UL << MIN_PARTITION_PER_THREAD_ORDER) - -/* - * The removed flag needs to be updated atomically with the pointer. - * It indicates that no node must attach to the node scheduled for - * removal, and that node garbage collection must be performed. - * The bucket flag does not require to be updated atomically with the - * pointer, but it is added as a pointer low bit flag to save space. - * The "removal owner" flag is used to detect which of the "del" - * operation that has set the "removed flag" gets to return the removed - * node to its caller. Note that the replace operation does not need to - * iteract with the "removal owner" flag, because it validates that - * the "removed" flag is not set before performing its cmpxchg. - */ -#define REMOVED_FLAG (1UL << 0) -#define BUCKET_FLAG (1UL << 1) -#define REMOVAL_OWNER_FLAG (1UL << 2) -#define FLAGS_MASK ((1UL << 3) - 1) - -/* 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_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 { - 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); -}; - -/* - * Algorithm to reverse bits in a word by lookup table, extended to - * 64-bit words. - * Source: - * http://graphics.stanford.edu/~seander/bithacks.html#BitReverseTable - * Originally from Public Domain. - */ - -static const uint8_t BitReverseTable256[256] = -{ -#define R2(n) (n), (n) + 2*64, (n) + 1*64, (n) + 3*64 -#define R4(n) R2(n), R2((n) + 2*16), R2((n) + 1*16), R2((n) + 3*16) -#define R6(n) R4(n), R4((n) + 2*4 ), R4((n) + 1*4 ), R4((n) + 3*4 ) - R6(0), R6(2), R6(1), R6(3) -}; -#undef R2 -#undef R4 -#undef R6 - -static -uint8_t bit_reverse_u8(uint8_t v) -{ - return BitReverseTable256[v]; -} - -static __attribute__((unused)) -uint32_t bit_reverse_u32(uint32_t v) -{ - return ((uint32_t) bit_reverse_u8(v) << 24) | - ((uint32_t) bit_reverse_u8(v >> 8) << 16) | - ((uint32_t) bit_reverse_u8(v >> 16) << 8) | - ((uint32_t) bit_reverse_u8(v >> 24)); -} - -static __attribute__((unused)) -uint64_t bit_reverse_u64(uint64_t v) -{ - return ((uint64_t) bit_reverse_u8(v) << 56) | - ((uint64_t) bit_reverse_u8(v >> 8) << 48) | - ((uint64_t) bit_reverse_u8(v >> 16) << 40) | - ((uint64_t) bit_reverse_u8(v >> 24) << 32) | - ((uint64_t) bit_reverse_u8(v >> 32) << 24) | - ((uint64_t) bit_reverse_u8(v >> 40) << 16) | - ((uint64_t) bit_reverse_u8(v >> 48) << 8) | - ((uint64_t) bit_reverse_u8(v >> 56)); -} - -static -unsigned long bit_reverse_ulong(unsigned long v) -{ -#if (CAA_BITS_PER_LONG == 32) - return bit_reverse_u32(v); -#else - return bit_reverse_u64(v); -#endif -} - -/* - * fls: returns the position of the most significant bit. - * Returns 0 if no bit is set, else returns the position of the most - * significant bit (from 1 to 32 on 32-bit, from 1 to 64 on 64-bit). - */ -#if defined(__i386) || defined(__x86_64) -static inline -unsigned int fls_u32(uint32_t x) -{ - int r; - - asm("bsrl %1,%0\n\t" - "jnz 1f\n\t" - "movl $-1,%0\n\t" - "1:\n\t" - : "=r" (r) : "rm" (x)); - return r + 1; -} -#define HAS_FLS_U32 -#endif - -#if defined(__x86_64) -static inline -unsigned int fls_u64(uint64_t x) -{ - long r; - - asm("bsrq %1,%0\n\t" - "jnz 1f\n\t" - "movq $-1,%0\n\t" - "1:\n\t" - : "=r" (r) : "rm" (x)); - return r + 1; -} -#define HAS_FLS_U64 -#endif - -#ifndef HAS_FLS_U64 -static __attribute__((unused)) -unsigned int fls_u64(uint64_t x) -{ - unsigned int r = 64; - - if (!x) - return 0; - - if (!(x & 0xFFFFFFFF00000000ULL)) { - x <<= 32; - r -= 32; - } - if (!(x & 0xFFFF000000000000ULL)) { - x <<= 16; - r -= 16; - } - if (!(x & 0xFF00000000000000ULL)) { - x <<= 8; - r -= 8; - } - if (!(x & 0xF000000000000000ULL)) { - x <<= 4; - r -= 4; - } - if (!(x & 0xC000000000000000ULL)) { - x <<= 2; - r -= 2; - } - if (!(x & 0x8000000000000000ULL)) { - x <<= 1; - r -= 1; - } - return r; -} -#endif - -#ifndef HAS_FLS_U32 -static __attribute__((unused)) -unsigned int fls_u32(uint32_t x) -{ - unsigned int r = 32; - - if (!x) - return 0; - if (!(x & 0xFFFF0000U)) { - x <<= 16; - r -= 16; - } - if (!(x & 0xFF000000U)) { - x <<= 8; - r -= 8; - } - if (!(x & 0xF0000000U)) { - x <<= 4; - r -= 4; - } - if (!(x & 0xC0000000U)) { - x <<= 2; - r -= 2; - } - if (!(x & 0x80000000U)) { - x <<= 1; - r -= 1; - } - return r; -} -#endif - -unsigned int cds_lfht_fls_ulong(unsigned long x) -{ -#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 cds_lfht_get_count_order_u32(uint32_t x) -{ - if (!x) - return -1; - - return fls_u32(x - 1); -} - -/* - * Return the minimum order for which x <= (1UL << order). - * Return -1 if x is 0. - */ -int cds_lfht_get_count_order_ulong(unsigned long x) -{ - if (!x) - return -1; - - return cds_lfht_fls_ulong(x - 1); -} - -static -void cds_lfht_resize_lazy_grow(struct cds_lfht *ht, unsigned long size, int growth); - -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; -static int split_count_order = -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 << cds_lfht_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 -void alloc_split_items_count(struct cds_lfht *ht) -{ - struct ht_items_count *count; - - 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; - split_count_order = - cds_lfht_get_count_order_ulong(split_count_mask + 1); - } - - 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_split_items_count(struct cds_lfht *ht) -{ - poison_free(ht->split_count); -} - -#if defined(HAVE_SCHED_GETCPU) && !defined(VALGRIND) -static -int ht_get_split_count_index(unsigned long hash) -{ - int cpu; - - assert(split_count_mask >= 0); - cpu = sched_getcpu(); - if (caa_unlikely(cpu < 0)) - return hash & split_count_mask; - else - 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, unsigned long hash) -{ - unsigned long split_count; - int index; - long count; - - if (caa_unlikely(!ht->split_count)) - return; - index = ht_get_split_count_index(hash); - split_count = uatomic_add_return(&ht->split_count[index].add, 1); - if (caa_likely(split_count & ((1UL << COUNT_COMMIT_ORDER) - 1))) - return; - /* Only if number of add multiple of 1UL << COUNT_COMMIT_ORDER */ - - dbg_printf("add split count %lu\n", split_count); - count = uatomic_add_return(&ht->count, - 1UL << COUNT_COMMIT_ORDER); - if (caa_likely(count & (count - 1))) - return; - /* Only if global count is power of 2 */ - - if ((count >> CHAIN_LEN_RESIZE_THRESHOLD) < size) - return; - dbg_printf("add set global %ld\n", count); - cds_lfht_resize_lazy_count(ht, size, - count >> (CHAIN_LEN_TARGET - 1)); -} - -static -void ht_count_del(struct cds_lfht *ht, unsigned long size, unsigned long hash) -{ - unsigned long split_count; - int index; - long count; - - if (caa_unlikely(!ht->split_count)) - return; - index = ht_get_split_count_index(hash); - split_count = uatomic_add_return(&ht->split_count[index].del, 1); - if (caa_likely(split_count & ((1UL << COUNT_COMMIT_ORDER) - 1))) - return; - /* Only if number of deletes multiple of 1UL << COUNT_COMMIT_ORDER */ - - dbg_printf("del split count %lu\n", split_count); - count = uatomic_add_return(&ht->count, - -(1UL << COUNT_COMMIT_ORDER)); - if (caa_likely(count & (count - 1))) - return; - /* Only if global count is power of 2 */ - - if ((count >> CHAIN_LEN_RESIZE_THRESHOLD) >= size) - return; - dbg_printf("del set global %ld\n", count); - /* - * Don't shrink table if the number of nodes is below a - * certain threshold. - */ - if (count < (1UL << COUNT_COMMIT_ORDER) * (split_count_mask + 1)) - return; - cds_lfht_resize_lazy_count(ht, size, - count >> (CHAIN_LEN_TARGET - 1)); -} - -static -void check_resize(struct cds_lfht *ht, unsigned long size, uint32_t chain_len) -{ - unsigned long count; - - if (!(ht->flags & CDS_LFHT_AUTO_RESIZE)) - return; - count = uatomic_read(&ht->count); - /* - * Use bucket-local length for small table expand and for - * environments lacking per-cpu data support. - */ - if (count >= (1UL << (COUNT_COMMIT_ORDER + split_count_order))) - return; - if (chain_len > 100) - dbg_printf("WARNING: large chain length: %u.\n", - chain_len); - if (chain_len >= CHAIN_LEN_RESIZE_THRESHOLD) { - int growth; - - /* - * Ideal growth calculated based on chain length. - */ - growth = cds_lfht_get_count_order_u32(chain_len - - (CHAIN_LEN_TARGET - 1)); - if ((ht->flags & CDS_LFHT_ACCOUNTING) - && (size << growth) - >= (1UL << (COUNT_COMMIT_ORDER - + split_count_order))) { - /* - * If ideal growth expands the hash table size - * beyond the "small hash table" sizes, use the - * maximum small hash table size to attempt - * expanding the hash table. This only applies - * when node accounting is available, otherwise - * the chain length is used to expand the hash - * table in every case. - */ - growth = COUNT_COMMIT_ORDER + split_count_order - - cds_lfht_get_count_order_ulong(size); - if (growth <= 0) - return; - } - cds_lfht_resize_lazy_grow(ht, size, growth); - } -} - -static -struct cds_lfht_node *clear_flag(struct cds_lfht_node *node) -{ - return (struct cds_lfht_node *) (((unsigned long) node) & ~FLAGS_MASK); -} - -static -int is_removed(struct cds_lfht_node *node) -{ - return ((unsigned long) node) & REMOVED_FLAG; -} - -static -int is_bucket(struct cds_lfht_node *node) -{ - return ((unsigned long) node) & BUCKET_FLAG; -} - -static -struct cds_lfht_node *flag_bucket(struct cds_lfht_node *node) -{ - return (struct cds_lfht_node *) (((unsigned long) node) | BUCKET_FLAG); -} - -static -int is_removal_owner(struct cds_lfht_node *node) -{ - return ((unsigned long) node) & REMOVAL_OWNER_FLAG; -} - -static -struct cds_lfht_node *flag_removal_owner(struct cds_lfht_node *node) -{ - return (struct cds_lfht_node *) (((unsigned long) node) | REMOVAL_OWNER_FLAG); -} - -static -struct cds_lfht_node *flag_removed_or_removal_owner(struct cds_lfht_node *node) -{ - return (struct cds_lfht_node *) (((unsigned long) node) | REMOVED_FLAG | REMOVAL_OWNER_FLAG); -} - -static -struct cds_lfht_node *get_end(void) -{ - return (struct cds_lfht_node *) END_VALUE; -} - -static -int is_end(struct cds_lfht_node *node) -{ - return clear_flag(node) == (struct cds_lfht_node *) END_VALUE; -} - -static -unsigned long _uatomic_xchg_monotonic_increase(unsigned long *ptr, - unsigned long v) -{ - unsigned long old1, old2; - - old1 = uatomic_read(ptr); - do { - old2 = old1; - if (old2 >= v) - return old2; - } while ((old1 = uatomic_cmpxchg(ptr, old2, v)) != old2); - return old2; -} - -static -void cds_lfht_alloc_bucket_table(struct cds_lfht *ht, unsigned long order) -{ - return ht->mm->alloc_bucket_table(ht, order); -} - -/* - * cds_lfht_free_bucket_table() should be called with decreasing order. - * When cds_lfht_free_bucket_table(0) is called, it means the whole - * lfht is destroyed. - */ -static -void cds_lfht_free_bucket_table(struct cds_lfht *ht, unsigned long order) -{ - return ht->mm->free_bucket_table(ht, order); -} - -static inline -struct cds_lfht_node *bucket_at(struct cds_lfht *ht, unsigned long index) -{ - return ht->bucket_at(ht, index); -} - -static inline -struct cds_lfht_node *lookup_bucket(struct cds_lfht *ht, unsigned long size, - unsigned long hash) -{ - assert(size > 0); - return bucket_at(ht, hash & (size - 1)); -} - -/* - * Remove all logically deleted nodes from a bucket up to a certain node key. - */ -static -void _cds_lfht_gc_bucket(struct cds_lfht_node *bucket, struct cds_lfht_node *node) -{ - struct cds_lfht_node *iter_prev, *iter, *next, *new_next; - - assert(!is_bucket(bucket)); - assert(!is_removed(bucket)); - assert(!is_bucket(node)); - assert(!is_removed(node)); - for (;;) { - iter_prev = bucket; - /* We can always skip the bucket node initially */ - iter = rcu_dereference(iter_prev->next); - assert(!is_removed(iter)); - assert(iter_prev->reverse_hash <= node->reverse_hash); - /* - * We should never be called with bucket (start of chain) - * and logically removed node (end of path compression - * marker) being the actual same node. This would be a - * bug in the algorithm implementation. - */ - assert(bucket != node); - for (;;) { - if (caa_unlikely(is_end(iter))) - return; - if (caa_likely(clear_flag(iter)->reverse_hash > node->reverse_hash)) - return; - next = rcu_dereference(clear_flag(iter)->next); - if (caa_likely(is_removed(next))) - break; - iter_prev = clear_flag(iter); - iter = next; - } - assert(!is_removed(iter)); - if (is_bucket(iter)) - new_next = flag_bucket(clear_flag(next)); - else - new_next = clear_flag(next); - (void) uatomic_cmpxchg(&iter_prev->next, iter, new_next); - } -} - -static -int _cds_lfht_replace(struct cds_lfht *ht, unsigned long size, - struct cds_lfht_node *old_node, - struct cds_lfht_node *old_next, - struct cds_lfht_node *new_node) -{ - struct cds_lfht_node *bucket, *ret_next; - - if (!old_node) /* Return -ENOENT if asked to replace NULL node */ - return -ENOENT; - - assert(!is_removed(old_node)); - assert(!is_bucket(old_node)); - assert(!is_removed(new_node)); - assert(!is_bucket(new_node)); - assert(new_node != old_node); - for (;;) { - /* Insert after node to be replaced */ - if (is_removed(old_next)) { - /* - * Too late, the old node has been removed under us - * between lookup and replace. Fail. - */ - return -ENOENT; - } - assert(old_next == clear_flag(old_next)); - assert(new_node != old_next); - /* - * REMOVAL_OWNER flag is _NEVER_ set before the REMOVED - * flag. It is either set atomically at the same time - * (replace) or after (del). - */ - assert(!is_removal_owner(old_next)); - new_node->next = old_next; - /* - * Here is the whole trick for lock-free replace: we add - * the replacement node _after_ the node we want to - * replace by atomically setting its next pointer at the - * same time we set its removal flag. Given that - * the lookups/get next use an iterator aware of the - * next pointer, they will either skip the old node due - * to the removal flag and see the new node, or use - * the old node, but will not see the new one. - * This is a replacement of a node with another node - * that has the same value: we are therefore not - * removing a value from the hash table. We set both the - * REMOVED and REMOVAL_OWNER flags atomically so we own - * the node after successful cmpxchg. - */ - ret_next = uatomic_cmpxchg(&old_node->next, - old_next, flag_removed_or_removal_owner(new_node)); - 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. - */ - bucket = lookup_bucket(ht, size, bit_reverse_ulong(old_node->reverse_hash)); - _cds_lfht_gc_bucket(bucket, new_node); - - assert(is_removed(CMM_LOAD_SHARED(old_node->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 -void _cds_lfht_add(struct cds_lfht *ht, - unsigned long hash, - cds_lfht_match_fct match, - const void *key, - unsigned long size, - struct cds_lfht_node *node, - struct cds_lfht_iter *unique_ret, - int bucket_flag) -{ - struct cds_lfht_node *iter_prev, *iter, *next, *new_node, *new_next, - *return_node; - struct cds_lfht_node *bucket; - - assert(!is_bucket(node)); - assert(!is_removed(node)); - bucket = lookup_bucket(ht, size, hash); - for (;;) { - uint32_t chain_len = 0; - - /* - * iter_prev points to the non-removed node prior to the - * insert location. - */ - iter_prev = bucket; - /* We can always skip the bucket node initially */ - iter = rcu_dereference(iter_prev->next); - assert(iter_prev->reverse_hash <= node->reverse_hash); - for (;;) { - if (caa_unlikely(is_end(iter))) - goto insert; - if (caa_likely(clear_flag(iter)->reverse_hash > node->reverse_hash)) - goto insert; - - /* bucket node is the first node of the identical-hash-value chain */ - if (bucket_flag && clear_flag(iter)->reverse_hash == node->reverse_hash) - goto insert; - - next = rcu_dereference(clear_flag(iter)->next); - if (caa_unlikely(is_removed(next))) - goto gc_node; - - /* uniquely add */ - if (unique_ret - && !is_bucket(next) - && clear_flag(iter)->reverse_hash == node->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 traversing the table node by - * node by forward iterations) - */ - cds_lfht_next_duplicate(ht, match, key, &d_iter); - if (!d_iter.node) - goto insert; - - *unique_ret = d_iter; - return; - } - - /* Only account for identical reverse hash once */ - if (iter_prev->reverse_hash != clear_flag(iter)->reverse_hash - && !is_bucket(next)) - check_resize(ht, size, ++chain_len); - iter_prev = clear_flag(iter); - iter = next; - } - - insert: - assert(node != clear_flag(iter)); - assert(!is_removed(iter_prev)); - assert(!is_removed(iter)); - assert(iter_prev != node); - if (!bucket_flag) - node->next = clear_flag(iter); - else - node->next = flag_bucket(clear_flag(iter)); - if (is_bucket(iter)) - new_node = flag_bucket(node); - else - new_node = node; - if (uatomic_cmpxchg(&iter_prev->next, iter, - new_node) != iter) { - continue; /* retry */ - } else { - return_node = node; - goto end; - } - - gc_node: - assert(!is_removed(iter)); - if (is_bucket(iter)) - new_next = flag_bucket(clear_flag(next)); - else - new_next = clear_flag(next); - (void) uatomic_cmpxchg(&iter_prev->next, iter, new_next); - /* retry */ - } -end: - if (unique_ret) { - unique_ret->node = return_node; - /* unique_ret->next left unset, never used. */ - } -} - -static -int _cds_lfht_del(struct cds_lfht *ht, unsigned long size, - struct cds_lfht_node *node) -{ - struct cds_lfht_node *bucket, *next; - - if (!node) /* Return -ENOENT if asked to delete NULL node */ - return -ENOENT; - - /* logically delete the node */ - assert(!is_bucket(node)); - assert(!is_removed(node)); - assert(!is_removal_owner(node)); - - /* - * We are first checking if the node had previously been - * logically removed (this check is not atomic with setting the - * logical removal flag). Return -ENOENT if the node had - * previously been removed. - */ - next = CMM_LOAD_SHARED(node->next); /* next is not dereferenced */ - if (caa_unlikely(is_removed(next))) - return -ENOENT; - assert(!is_bucket(next)); - /* - * The del operation semantic guarantees a full memory barrier - * before the uatomic_or atomic commit of the deletion flag. - */ - cmm_smp_mb__before_uatomic_or(); - /* - * We set the REMOVED_FLAG unconditionally. Note that there may - * be more than one concurrent thread setting this flag. - * Knowing which wins the race will be known after the garbage - * collection phase, stay tuned! - */ - uatomic_or(&node->next, REMOVED_FLAG); - /* We performed the (logical) deletion. */ - - /* - * 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. - */ - bucket = lookup_bucket(ht, size, bit_reverse_ulong(node->reverse_hash)); - _cds_lfht_gc_bucket(bucket, node); - - assert(is_removed(CMM_LOAD_SHARED(node->next))); - /* - * Last phase: atomically exchange node->next with a version - * having "REMOVAL_OWNER_FLAG" set. If the returned node->next - * pointer did _not_ have "REMOVAL_OWNER_FLAG" set, we now own - * the node and win the removal race. - * It is interesting to note that all "add" paths are forbidden - * to change the next pointer starting from the point where the - * REMOVED_FLAG is set, so here using a read, followed by a - * xchg() suffice to guarantee that the xchg() will ever only - * set the "REMOVAL_OWNER_FLAG" (or change nothing if the flag - * was already set). - */ - if (!is_removal_owner(uatomic_xchg(&node->next, - flag_removal_owner(node->next)))) - return 0; - else - return -ENOENT; -} - -static -void *partition_resize_thread(void *arg) -{ - struct partition_resize_work *work = arg; - - work->ht->flavor->register_thread(); - work->fct(work->ht, work->i, work->start, work->len); - work->ht->flavor->unregister_thread(); - return NULL; -} - -static -void partition_resize_helper(struct cds_lfht *ht, unsigned long i, - unsigned long len, - void (*fct)(struct cds_lfht *ht, unsigned long i, - unsigned long start, unsigned long len)) -{ - unsigned long partition_len; - struct partition_resize_work *work; - int thread, ret; - unsigned long nr_threads; - - /* - * Note: nr_cpus_mask + 1 is always power of 2. - * We spawn just the number of threads we need to satisfy the minimum - * partition size, up to the number of CPUs in the system. - */ - if (nr_cpus_mask > 0) { - nr_threads = min(nr_cpus_mask + 1, - len >> MIN_PARTITION_PER_THREAD_ORDER); - } else { - nr_threads = 1; - } - partition_len = len >> cds_lfht_get_count_order_ulong(nr_threads); - work = calloc(nr_threads, sizeof(*work)); - assert(work); - for (thread = 0; thread < nr_threads; thread++) { - work[thread].ht = ht; - work[thread].i = i; - work[thread].len = partition_len; - work[thread].start = thread * partition_len; - work[thread].fct = fct; - 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(work[thread].thread_id, NULL); - assert(!ret); - } - free(work); -} - -/* - * Holding RCU read lock to protect _cds_lfht_add against memory - * reclaim that could be performed by other call_rcu worker threads (ABA - * problem). - * - * When we reach a certain length, we can split this population phase over - * many worker threads, based on the number of CPUs available in the system. - * This should therefore take care of not having the expand lagging behind too - * many concurrent insertion threads by using the scheduler's ability to - * schedule bucket node population fairly with insertions. - */ -static -void init_table_populate_partition(struct cds_lfht *ht, unsigned long i, - unsigned long start, unsigned long len) -{ - unsigned long j, size = 1UL << (i - 1); - - assert(i > MIN_TABLE_ORDER); - ht->flavor->read_lock(); - for (j = size + start; j < size + start + len; j++) { - struct cds_lfht_node *new_node = bucket_at(ht, j); - - assert(j >= size && j < (size << 1)); - dbg_printf("init populate: order %lu index %lu hash %lu\n", - i, j, j); - new_node->reverse_hash = bit_reverse_ulong(j); - _cds_lfht_add(ht, j, NULL, NULL, size, new_node, NULL, 1); - } - ht->flavor->read_unlock(); -} - -static -void init_table_populate(struct cds_lfht *ht, unsigned long i, - unsigned long len) -{ - assert(nr_cpus_mask != -1); - if (nr_cpus_mask < 0 || len < 2 * MIN_PARTITION_PER_THREAD) { - ht->flavor->thread_online(); - init_table_populate_partition(ht, i, 0, len); - ht->flavor->thread_offline(); - return; - } - partition_resize_helper(ht, i, len, init_table_populate_partition); -} - -static -void init_table(struct cds_lfht *ht, - unsigned long first_order, unsigned long last_order) -{ - unsigned long i; - - dbg_printf("init table: first_order %lu last_order %lu\n", - first_order, last_order); - assert(first_order > MIN_TABLE_ORDER); - for (i = first_order; i <= last_order; i++) { - unsigned long len; - - 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->resize_target) < (1UL << i)) - break; - - cds_lfht_alloc_bucket_table(ht, i); - - /* - * Set all bucket nodes reverse hash values for a level and - * link all bucket nodes into the table. - */ - init_table_populate(ht, i, len); - - /* - * Update table size. - */ - cmm_smp_wmb(); /* populate data before RCU size */ - CMM_STORE_SHARED(ht->size, 1UL << i); - - dbg_printf("init new size: %lu\n", 1UL << i); - if (CMM_LOAD_SHARED(ht->in_progress_destroy)) - break; - } -} - -/* - * Holding RCU read lock to protect _cds_lfht_remove against memory - * reclaim that could be performed by other call_rcu worker threads (ABA - * problem). - * For a single level, we logically remove and garbage collect each node. - * - * As a design choice, we perform logical removal and garbage collection on a - * node-per-node basis to simplify this algorithm. We also assume keeping good - * cache locality of the operation would overweight possible performance gain - * that could be achieved by batching garbage collection for multiple levels. - * However, this would have to be justified by benchmarks. - * - * Concurrent removal and add operations are helping us perform garbage - * collection of logically removed nodes. We guarantee that all logically - * removed nodes have been garbage-collected (unlinked) before call_rcu is - * invoked to free a hole level of bucket nodes (after a grace period). - * - * Logical removal and garbage collection can therefore be done in batch - * or on a node-per-node basis, as long as the guarantee above holds. - * - * When we reach a certain length, we can split this removal over many worker - * threads, based on the number of CPUs available in the system. This should - * take care of not letting resize process lag behind too many concurrent - * updater threads actively inserting into the hash table. - */ -static -void remove_table_partition(struct cds_lfht *ht, unsigned long i, - unsigned long start, unsigned long len) -{ - unsigned long j, size = 1UL << (i - 1); - - assert(i > MIN_TABLE_ORDER); - ht->flavor->read_lock(); - for (j = size + start; j < size + start + len; j++) { - struct cds_lfht_node *fini_bucket = bucket_at(ht, j); - struct cds_lfht_node *parent_bucket = bucket_at(ht, j - size); - - assert(j >= size && j < (size << 1)); - dbg_printf("remove entry: order %lu index %lu hash %lu\n", - i, j, j); - /* Set the REMOVED_FLAG to freeze the ->next for gc */ - uatomic_or(&fini_bucket->next, REMOVED_FLAG); - _cds_lfht_gc_bucket(parent_bucket, fini_bucket); - } - ht->flavor->read_unlock(); -} - -static -void remove_table(struct cds_lfht *ht, unsigned long i, unsigned long len) -{ - - assert(nr_cpus_mask != -1); - if (nr_cpus_mask < 0 || len < 2 * MIN_PARTITION_PER_THREAD) { - ht->flavor->thread_online(); - remove_table_partition(ht, i, 0, len); - ht->flavor->thread_offline(); - return; - } - partition_resize_helper(ht, i, len, remove_table_partition); -} - -/* - * fini_table() is never called for first_order == 0, which is why - * free_by_rcu_order == 0 can be used as criterion to know if free must - * be called. - */ -static -void fini_table(struct cds_lfht *ht, - unsigned long first_order, unsigned long last_order) -{ - long i; - unsigned long free_by_rcu_order = 0; - - dbg_printf("fini table: first_order %lu last_order %lu\n", - first_order, last_order); - assert(first_order > MIN_TABLE_ORDER); - for (i = last_order; i >= first_order; i--) { - unsigned long len; - - len = 1UL << (i - 1); - dbg_printf("fini order %lu len: %lu\n", i, len); - - /* Stop shrink if the resize target changes under us */ - if (CMM_LOAD_SHARED(ht->resize_target) > (1UL << (i - 1))) - break; - - cmm_smp_wmb(); /* populate data before RCU size */ - CMM_STORE_SHARED(ht->size, 1UL << (i - 1)); - - /* - * We need to wait for all add operations to reach Q.S. (and - * thus use the new table for lookups) before we can start - * releasing the old bucket nodes. Otherwise their lookup will - * return a logically removed node as insert position. - */ - ht->flavor->update_synchronize_rcu(); - if (free_by_rcu_order) - cds_lfht_free_bucket_table(ht, free_by_rcu_order); - - /* - * Set "removed" flag in bucket nodes about to be removed. - * Unlink all now-logically-removed bucket node pointers. - * Concurrent add/remove operation are helping us doing - * the gc. - */ - remove_table(ht, i, len); - - free_by_rcu_order = i; - - dbg_printf("fini new size: %lu\n", 1UL << i); - if (CMM_LOAD_SHARED(ht->in_progress_destroy)) - break; - } - - if (free_by_rcu_order) { - ht->flavor->update_synchronize_rcu(); - cds_lfht_free_bucket_table(ht, free_by_rcu_order); - } -} - -static -void cds_lfht_create_bucket(struct cds_lfht *ht, unsigned long size) -{ - struct cds_lfht_node *prev, *node; - unsigned long order, len, i; - - cds_lfht_alloc_bucket_table(ht, 0); - - dbg_printf("create bucket: order 0 index 0 hash 0\n"); - node = bucket_at(ht, 0); - node->next = flag_bucket(get_end()); - node->reverse_hash = 0; - - for (order = 1; order < cds_lfht_get_count_order_ulong(size) + 1; order++) { - len = 1UL << (order - 1); - cds_lfht_alloc_bucket_table(ht, order); - - for (i = 0; i < len; i++) { - /* - * Now, we are trying to init the node with the - * hash=(len+i) (which is also a bucket with the - * index=(len+i)) and insert it into the hash table, - * so this node has to be inserted after the bucket - * with the index=(len+i)&(len-1)=i. And because there - * is no other non-bucket node nor bucket node with - * larger index/hash inserted, so the bucket node - * being inserted should be inserted directly linked - * after the bucket node with index=i. - */ - prev = bucket_at(ht, i); - node = bucket_at(ht, len + i); - - dbg_printf("create bucket: order %lu index %lu hash %lu\n", - order, len + i, len + i); - node->reverse_hash = bit_reverse_ulong(len + i); - - /* insert after prev */ - assert(is_bucket(prev->next)); - node->next = prev->next; - prev->next = flag_bucket(node); - } - } -} - -struct cds_lfht *_cds_lfht_new(unsigned long init_size, - unsigned long min_nr_alloc_buckets, - unsigned long max_nr_buckets, - int flags, - const struct cds_lfht_mm_type *mm, - const struct rcu_flavor_struct *flavor, - pthread_attr_t *attr) -{ - struct cds_lfht *ht; - unsigned long order; - - /* min_nr_alloc_buckets must be power of two */ - if (!min_nr_alloc_buckets || (min_nr_alloc_buckets & (min_nr_alloc_buckets - 1))) - return NULL; - - /* init_size must be power of two */ - if (!init_size || (init_size & (init_size - 1))) - return NULL; - - /* - * Memory management plugin default. - */ - if (!mm) { - if (CAA_BITS_PER_LONG > 32 - && max_nr_buckets - && max_nr_buckets <= (1ULL << 32)) { - /* - * For 64-bit architectures, with max number of - * buckets small enough not to use the entire - * 64-bit memory mapping space (and allowing a - * fair number of hash table instances), use the - * mmap allocator, which is faster than the - * order allocator. - */ - mm = &cds_lfht_mm_mmap; - } else { - /* - * The fallback is to use the order allocator. - */ - mm = &cds_lfht_mm_order; - } - } - - /* max_nr_buckets == 0 for order based mm means infinite */ - if (mm == &cds_lfht_mm_order && !max_nr_buckets) - max_nr_buckets = 1UL << (MAX_TABLE_ORDER - 1); - - /* max_nr_buckets must be power of two */ - if (!max_nr_buckets || (max_nr_buckets & (max_nr_buckets - 1))) - return NULL; - - min_nr_alloc_buckets = max(min_nr_alloc_buckets, MIN_TABLE_SIZE); - init_size = max(init_size, MIN_TABLE_SIZE); - max_nr_buckets = max(max_nr_buckets, min_nr_alloc_buckets); - init_size = min(init_size, max_nr_buckets); - - ht = mm->alloc_cds_lfht(min_nr_alloc_buckets, max_nr_buckets); - assert(ht); - assert(ht->mm == mm); - assert(ht->bucket_at == mm->bucket_at); - - ht->flags = flags; - ht->flavor = flavor; - ht->resize_attr = attr; - alloc_split_items_count(ht); - /* this mutex should not nest in read-side C.S. */ - pthread_mutex_init(&ht->resize_mutex, NULL); - order = cds_lfht_get_count_order_ulong(init_size); - ht->resize_target = 1UL << order; - cds_lfht_create_bucket(ht, 1UL << order); - ht->size = 1UL << order; - return ht; -} - -void cds_lfht_lookup(struct cds_lfht *ht, unsigned long hash, - cds_lfht_match_fct match, const void *key, - struct cds_lfht_iter *iter) -{ - struct cds_lfht_node *node, *next, *bucket; - unsigned long reverse_hash, size; - - reverse_hash = bit_reverse_ulong(hash); - - size = rcu_dereference(ht->size); - bucket = lookup_bucket(ht, size, hash); - /* We can always skip the bucket node initially */ - node = rcu_dereference(bucket->next); - node = clear_flag(node); - for (;;) { - if (caa_unlikely(is_end(node))) { - node = next = NULL; - break; - } - if (caa_unlikely(node->reverse_hash > reverse_hash)) { - node = next = NULL; - break; - } - next = rcu_dereference(node->next); - assert(node == clear_flag(node)); - if (caa_likely(!is_removed(next)) - && !is_bucket(next) - && node->reverse_hash == reverse_hash - && caa_likely(match(node, key))) { - break; - } - node = clear_flag(next); - } - assert(!node || !is_bucket(CMM_LOAD_SHARED(node->next))); - iter->node = node; - iter->next = next; -} - -void cds_lfht_next_duplicate(struct cds_lfht *ht, cds_lfht_match_fct match, - const void *key, struct cds_lfht_iter *iter) -{ - struct cds_lfht_node *node, *next; - unsigned long reverse_hash; - - node = iter->node; - reverse_hash = node->reverse_hash; - next = iter->next; - node = clear_flag(next); - - for (;;) { - if (caa_unlikely(is_end(node))) { - node = next = NULL; - break; - } - if (caa_unlikely(node->reverse_hash > reverse_hash)) { - node = next = NULL; - break; - } - next = rcu_dereference(node->next); - if (caa_likely(!is_removed(next)) - && !is_bucket(next) - && caa_likely(match(node, key))) { - break; - } - node = clear_flag(next); - } - assert(!node || !is_bucket(CMM_LOAD_SHARED(node->next))); - iter->node = node; - iter->next = next; -} - -void cds_lfht_next(struct cds_lfht *ht, struct cds_lfht_iter *iter) -{ - struct cds_lfht_node *node, *next; - - node = clear_flag(iter->next); - for (;;) { - if (caa_unlikely(is_end(node))) { - node = next = NULL; - break; - } - next = rcu_dereference(node->next); - if (caa_likely(!is_removed(next)) - && !is_bucket(next)) { - break; - } - node = clear_flag(next); - } - assert(!node || !is_bucket(CMM_LOAD_SHARED(node->next))); - iter->node = node; - iter->next = next; -} - -void cds_lfht_first(struct cds_lfht *ht, struct cds_lfht_iter *iter) -{ - /* - * Get next after first bucket node. The first bucket node is the - * first node of the linked list. - */ - iter->next = bucket_at(ht, 0)->next; - cds_lfht_next(ht, iter); -} - -void cds_lfht_add(struct cds_lfht *ht, unsigned long hash, - struct cds_lfht_node *node) -{ - unsigned long size; - - node->reverse_hash = bit_reverse_ulong(hash); - size = rcu_dereference(ht->size); - _cds_lfht_add(ht, hash, NULL, NULL, size, node, NULL, 0); - ht_count_add(ht, size, hash); -} - -struct cds_lfht_node *cds_lfht_add_unique(struct cds_lfht *ht, - unsigned long hash, - cds_lfht_match_fct match, - const void *key, - struct cds_lfht_node *node) -{ - unsigned long size; - struct cds_lfht_iter iter; - - node->reverse_hash = bit_reverse_ulong(hash); - size = rcu_dereference(ht->size); - _cds_lfht_add(ht, hash, match, key, 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, - unsigned long hash, - cds_lfht_match_fct match, - const void *key, - struct cds_lfht_node *node) -{ - unsigned long size; - struct cds_lfht_iter iter; - - node->reverse_hash = bit_reverse_ulong(hash); - size = rcu_dereference(ht->size); - for (;;) { - _cds_lfht_add(ht, hash, match, key, 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, - unsigned long hash, - cds_lfht_match_fct match, - const void *key, - struct cds_lfht_node *new_node) -{ - unsigned long size; - - new_node->reverse_hash = bit_reverse_ulong(hash); - if (!old_iter->node) - return -ENOENT; - if (caa_unlikely(old_iter->node->reverse_hash != new_node->reverse_hash)) - return -EINVAL; - if (caa_unlikely(!match(old_iter->node, key))) - return -EINVAL; - size = rcu_dereference(ht->size); - return _cds_lfht_replace(ht, size, old_iter->node, old_iter->next, - new_node); -} - -int cds_lfht_del(struct cds_lfht *ht, struct cds_lfht_node *node) -{ - unsigned long size, hash; - int ret; - - size = rcu_dereference(ht->size); - ret = _cds_lfht_del(ht, size, node); - if (!ret) { - hash = bit_reverse_ulong(node->reverse_hash); - ht_count_del(ht, size, hash); - } - return ret; -} - -int cds_lfht_is_node_deleted(struct cds_lfht_node *node) -{ - return is_removed(CMM_LOAD_SHARED(node->next)); -} - -static -int cds_lfht_delete_bucket(struct cds_lfht *ht) -{ - struct cds_lfht_node *node; - unsigned long order, i, size; - - /* Check that the table is empty */ - node = bucket_at(ht, 0); - do { - node = clear_flag(node)->next; - if (!is_bucket(node)) - return -EPERM; - assert(!is_removed(node)); - } while (!is_end(node)); - /* - * size accessed without rcu_dereference because hash table is - * being destroyed. - */ - size = ht->size; - /* Internal sanity check: all nodes left should be buckets */ - for (i = 0; i < size; i++) { - node = bucket_at(ht, i); - dbg_printf("delete bucket: index %lu expected hash %lu hash %lu\n", - i, i, bit_reverse_ulong(node->reverse_hash)); - assert(is_bucket(node->next)); - } - - for (order = cds_lfht_get_count_order_ulong(size); (long)order >= 0; order--) - cds_lfht_free_bucket_table(ht, order); - - return 0; -} - -/* - * Should only be called when no more concurrent readers nor writers can - * possibly access the table. - */ -int cds_lfht_destroy(struct cds_lfht *ht, pthread_attr_t **attr) -{ - int ret; -#ifdef rcu_read_ongoing_mb - int was_online; -#endif - - /* Wait for in-flight resize operations to complete */ - _CMM_STORE_SHARED(ht->in_progress_destroy, 1); - cmm_smp_mb(); /* Store destroy before load resize */ -#ifdef rcu_read_ongoing_mb - was_online = ht->flavor->read_ongoing(); - if (was_online) - ht->flavor->thread_offline(); - /* Calling with RCU read-side held is an error. */ - if (ht->flavor->read_ongoing()) { - ret = -EINVAL; - if (was_online) - ht->flavor->thread_online(); - goto end; - } -#endif - while (uatomic_read(&ht->in_progress_resize)) - (void) poll(NULL, 0, 100); /* wait for 100ms */ - ret = cds_lfht_delete_bucket(ht); - if (ret) - return ret; - free_split_items_count(ht); - if (attr) - *attr = ht->resize_attr; - poison_free(ht); -#ifdef rcu_read_ongoing_mb -end: -#endif - return ret; -} - -void cds_lfht_count_nodes(struct cds_lfht *ht, - long *approx_before, - unsigned long *count, - long *approx_after) -{ - struct cds_lfht_node *node, *next; - unsigned long nr_bucket = 0, nr_removed = 0; - - *approx_before = 0; - if (ht->split_count) { - int i; - - 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); - } - } - - *count = 0; - - /* Count non-bucket nodes in the table */ - node = bucket_at(ht, 0); - do { - next = rcu_dereference(node->next); - if (is_removed(next)) { - if (!is_bucket(next)) - (nr_removed)++; - else - (nr_bucket)++; - } else if (!is_bucket(next)) - (*count)++; - else - (nr_bucket)++; - node = clear_flag(next); - } while (!is_end(node)); - dbg_printf("number of logically removed nodes: %lu\n", nr_removed); - dbg_printf("number of bucket nodes: %lu\n", nr_bucket); - *approx_after = 0; - if (ht->split_count) { - int i; - - 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); - } - } -} - -/* called with resize mutex held */ -static -void _do_cds_lfht_grow(struct cds_lfht *ht, - unsigned long old_size, unsigned long new_size) -{ - unsigned long old_order, new_order; - - old_order = cds_lfht_get_count_order_ulong(old_size); - new_order = cds_lfht_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 + 1, new_order); -} - -/* called with resize mutex held */ -static -void _do_cds_lfht_shrink(struct cds_lfht *ht, - unsigned long old_size, unsigned long new_size) -{ - unsigned long old_order, new_order; - - new_size = max(new_size, MIN_TABLE_SIZE); - old_order = cds_lfht_get_count_order_ulong(old_size); - new_order = cds_lfht_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 bucket nodes to remove. */ - fini_table(ht, new_order + 1, old_order); -} - - -/* called with resize mutex held */ -static -void _do_cds_lfht_resize(struct cds_lfht *ht) -{ - unsigned long new_size, old_size; - - /* - * 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->resize_initiated = 1; - old_size = ht->size; - new_size = CMM_LOAD_SHARED(ht->resize_target); - if (old_size < new_size) - _do_cds_lfht_grow(ht, old_size, new_size); - else if (old_size > new_size) - _do_cds_lfht_shrink(ht, old_size, new_size); - ht->resize_initiated = 0; - /* write resize_initiated before read resize_target */ - cmm_smp_mb(); - } while (ht->size != CMM_LOAD_SHARED(ht->resize_target)); -} - -static -unsigned long resize_target_grow(struct cds_lfht *ht, unsigned long new_size) -{ - return _uatomic_xchg_monotonic_increase(&ht->resize_target, new_size); -} - -static -void resize_target_update_count(struct cds_lfht *ht, - unsigned long count) -{ - count = max(count, MIN_TABLE_SIZE); - count = min(count, ht->max_nr_buckets); - uatomic_set(&ht->resize_target, count); -} - -void cds_lfht_resize(struct cds_lfht *ht, unsigned long new_size) -{ -#ifdef rcu_read_ongoing_mb - int was_online; - - was_online = ht->flavor->read_ongoing(); - if (was_online) - ht->flavor->thread_offline(); - /* Calling with RCU read-side held is an error. */ - if (ht->flavor->read_ongoing()) { - static int print_once; - - if (!CMM_LOAD_SHARED(print_once)) - fprintf(stderr, "[error] rculfhash: cds_lfht_resize " - "called with RCU read-side lock held.\n"); - CMM_STORE_SHARED(print_once, 1); - assert(0); - goto end; - } -#endif - resize_target_update_count(ht, new_size); - CMM_STORE_SHARED(ht->resize_initiated, 1); - pthread_mutex_lock(&ht->resize_mutex); - _do_cds_lfht_resize(ht); - pthread_mutex_unlock(&ht->resize_mutex); -#ifdef rcu_read_ongoing_mb -end: - if (was_online) - ht->flavor->thread_online(); -#endif -} - -static -void do_resize_cb(struct rcu_head *head) -{ - struct rcu_resize_work *work = - caa_container_of(head, struct rcu_resize_work, head); - struct cds_lfht *ht = work->ht; - - ht->flavor->thread_offline(); - pthread_mutex_lock(&ht->resize_mutex); - _do_cds_lfht_resize(ht); - pthread_mutex_unlock(&ht->resize_mutex); - ht->flavor->thread_online(); - poison_free(work); - cmm_smp_mb(); /* finish resize before decrement */ - uatomic_dec(&ht->in_progress_resize); -} - -static -void __cds_lfht_resize_lazy_launch(struct cds_lfht *ht) -{ - struct rcu_resize_work *work; - - /* Store resize_target before read resize_initiated */ - cmm_smp_mb(); - if (!CMM_LOAD_SHARED(ht->resize_initiated)) { - uatomic_inc(&ht->in_progress_resize); - 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 = zmalloc(sizeof(*work)); - if (work == NULL) { - dbg_printf("error allocating resize work, bailing out\n"); - uatomic_dec(&ht->in_progress_resize); - return; - } - work->ht = ht; - ht->flavor->update_call_rcu(&work->head, do_resize_cb); - CMM_STORE_SHARED(ht->resize_initiated, 1); - } -} - -static -void cds_lfht_resize_lazy_grow(struct cds_lfht *ht, unsigned long size, int growth) -{ - unsigned long target_size = size << growth; - - target_size = min(target_size, ht->max_nr_buckets); - if (resize_target_grow(ht, target_size) >= target_size) - return; - - __cds_lfht_resize_lazy_launch(ht); -} - -/* - * We favor grow operations over shrink. A shrink operation never occurs - * if a grow operation is queued for lazy execution. A grow operation - * cancels any pending shrink lazy execution. - */ -static -void cds_lfht_resize_lazy_count(struct cds_lfht *ht, unsigned long size, - unsigned long count) -{ - if (!(ht->flags & CDS_LFHT_AUTO_RESIZE)) - return; - count = max(count, MIN_TABLE_SIZE); - count = min(count, ht->max_nr_buckets); - if (count == size) - return; /* Already the right size, no resize needed */ - if (count > size) { /* lazy grow */ - if (resize_target_grow(ht, count) >= count) - return; - } else { /* lazy shrink */ - for (;;) { - unsigned long s; - - s = uatomic_cmpxchg(&ht->resize_target, size, count); - if (s == size) - break; /* no resize needed */ - if (s > size) - return; /* growing is/(was just) in progress */ - if (s <= count) - return; /* some other thread do shrink */ - size = s; - } - } - __cds_lfht_resize_lazy_launch(ht); -} diff --git a/src/common/hashtable/rculfhash.h b/src/common/hashtable/rculfhash.h deleted file mode 100644 index adb5d9d4f..000000000 --- a/src/common/hashtable/rculfhash.h +++ /dev/null @@ -1,480 +0,0 @@ -#ifndef _URCU_RCULFHASH_H -#define _URCU_RCULFHASH_H - -/* - * urcu/rculfhash.h - * - * Userspace RCU library - Lock-Free RCU Hash Table - * - * Copyright 2011 - Mathieu Desnoyers - * Copyright 2011 - Lai Jiangshan - * - * 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 - * - * Include this file _after_ including your URCU flavor. - */ - -#include "hashtable-symbols.h" - -#include -#include -#include - -#include "urcu-flavor.h" - -#ifdef __cplusplus -extern "C" { -#endif - -/* - * cds_lfht_node: Contains the next pointers and reverse-hash - * value required for lookup and traversal of the hash table. - * - * struct cds_lfht_node should be aligned on 8-bytes boundaries because - * the three lower bits are used as flags. It is worth noting that the - * information contained within these three bits could be represented on - * two bits by re-using the same bit for REMOVAL_OWNER_FLAG and - * BUCKET_FLAG. This can be done if we ensure that no iterator nor - * updater check the BUCKET_FLAG after it detects that the REMOVED_FLAG - * is set. Given the minimum size of struct cds_lfht_node is 8 bytes on - * 32-bit architectures, we choose to go for simplicity and reserve - * three bits. - * - * struct cds_lfht_node can be embedded into a structure (as a field). - * caa_container_of() can be used to get the structure from the struct - * cds_lfht_node after a lookup. - * - * The structure which embeds it typically holds the key (or key-value - * pair) of the object. The caller code is responsible for calculation - * of the hash value for cds_lfht APIs. - */ -struct cds_lfht_node { - struct cds_lfht_node *next; /* ptr | REMOVAL_OWNER_FLAG | BUCKET_FLAG | REMOVED_FLAG */ - unsigned long reverse_hash; -} __attribute__((aligned(8))); - -/* cds_lfht_iter: Used to track state while traversing a hash chain. */ -struct cds_lfht_iter { - struct cds_lfht_node *node, *next; -}; - -static inline -struct cds_lfht_node *cds_lfht_iter_get_node(struct cds_lfht_iter *iter) -{ - return iter->node; -} - -struct cds_lfht; - -/* - * Caution ! - * Ensure reader and writer threads are registered as urcu readers. - */ - -typedef int (*cds_lfht_match_fct)(struct cds_lfht_node *node, const void *key); - -/* - * cds_lfht_node_init - initialize a hash table node - * @node: the node to initialize. - * - * This function is kept to be eventually used for debugging purposes - * (detection of memory corruption). - */ -static inline -void cds_lfht_node_init(struct cds_lfht_node *node) -{ -} - -/* - * Hash table creation flags. - */ -enum { - CDS_LFHT_AUTO_RESIZE = (1U << 0), - CDS_LFHT_ACCOUNTING = (1U << 1), -}; - -struct cds_lfht_mm_type { - struct cds_lfht *(*alloc_cds_lfht)(unsigned long min_nr_alloc_buckets, - unsigned long max_nr_buckets); - void (*alloc_bucket_table)(struct cds_lfht *ht, unsigned long order); - void (*free_bucket_table)(struct cds_lfht *ht, unsigned long order); - struct cds_lfht_node *(*bucket_at)(struct cds_lfht *ht, - unsigned long index); -}; - -extern const struct cds_lfht_mm_type cds_lfht_mm_order; -extern const struct cds_lfht_mm_type cds_lfht_mm_chunk; -extern const struct cds_lfht_mm_type cds_lfht_mm_mmap; - -/* - * _cds_lfht_new - API used by cds_lfht_new wrapper. Do not use directly. - */ -struct cds_lfht *_cds_lfht_new(unsigned long init_size, - unsigned long min_nr_alloc_buckets, - unsigned long max_nr_buckets, - int flags, - const struct cds_lfht_mm_type *mm, - const struct rcu_flavor_struct *flavor, - pthread_attr_t *attr); - -/* - * cds_lfht_new - allocate a hash table. - * @init_size: number of buckets to allocate initially. Must be power of two. - * @min_nr_alloc_buckets: the minimum number of allocated buckets. - * (must be power of two) - * @max_nr_buckets: the maximum number of hash table buckets allowed. - * (must be power of two) - * @flags: hash table creation flags (can be combined with bitwise or: '|'). - * 0: no flags. - * CDS_LFHT_AUTO_RESIZE: automatically resize hash table. - * CDS_LFHT_ACCOUNTING: count the number of node addition - * and removal in the table - * @attr: optional resize worker thread attributes. NULL for default. - * - * Return NULL on error. - * Note: the RCU flavor must be already included before the hash table header. - * - * The programmer is responsible for ensuring that resize operation has a - * priority equal to hash table updater threads. It should be performed by - * specifying the appropriate priority in the pthread "attr" argument, and, - * for CDS_LFHT_AUTO_RESIZE, by ensuring that call_rcu worker threads also have - * this priority level. Having lower priority for call_rcu and resize threads - * does not pose any correctness issue, but the resize operations could be - * starved by updates, thus leading to long hash table bucket chains. - * Threads calling cds_lfht_new are NOT required to be registered RCU - * read-side threads. It can be called very early. (e.g. before RCU is - * initialized) - */ -static inline -struct cds_lfht *cds_lfht_new(unsigned long init_size, - unsigned long min_nr_alloc_buckets, - unsigned long max_nr_buckets, - int flags, - pthread_attr_t *attr) -{ - return _cds_lfht_new(init_size, min_nr_alloc_buckets, max_nr_buckets, - flags, NULL, &rcu_flavor, attr); -} - -/* - * cds_lfht_destroy - destroy a hash table. - * @ht: the hash table to destroy. - * @attr: (output) resize worker thread attributes, as received by cds_lfht_new. - * The caller will typically want to free this pointer if dynamically - * allocated. The attr point can be NULL if the caller does not - * need to be informed of the value passed to cds_lfht_new(). - * - * Return 0 on success, negative error value on error. - * Threads calling this API need to be registered RCU read-side threads. - * cds_lfht_destroy should *not* be called from a RCU read-side critical - * section. - */ -int cds_lfht_destroy(struct cds_lfht *ht, pthread_attr_t **attr); - -/* - * cds_lfht_count_nodes - count the number of nodes in the hash table. - * @ht: the hash table. - * @split_count_before: sample the node count split-counter before traversal. - * @count: traverse the hash table, count the number of nodes observed. - * @split_count_after: sample the node count split-counter after traversal. - * - * Call with rcu_read_lock held. - * Threads calling this API need to be registered RCU read-side threads. - */ -void cds_lfht_count_nodes(struct cds_lfht *ht, - long *split_count_before, - unsigned long *count, - long *split_count_after); - -/* - * cds_lfht_lookup - lookup a node by key. - * @ht: the hash table. - * @hash: the key hash. - * @match: the key match function. - * @key: the current node key. - * @iter: node, if found (output). *iter->node set to NULL if not found. - * - * Call with rcu_read_lock held. - * Threads calling this API need to be registered RCU read-side threads. - * This function acts as a rcu_dereference() to read the node pointer. - */ -void cds_lfht_lookup(struct cds_lfht *ht, unsigned long hash, - cds_lfht_match_fct match, const void *key, - struct cds_lfht_iter *iter); - -/* - * cds_lfht_next_duplicate - get the next item with same key, after iterator. - * @ht: the hash table. - * @match: the key match function. - * @key: the current node key. - * @iter: input: current iterator. - * output: node, if found. *iter->node set to NULL if not found. - * - * Uses an iterator initialized by a lookup or traversal. Important: the - * iterator _needs_ to be initialized before calling - * cds_lfht_next_duplicate. - * Sets *iter-node to the following node with same key. - * Sets *iter->node to NULL if no following node exists with same key. - * RCU read-side lock must be held across cds_lfht_lookup and - * cds_lfht_next calls, and also between cds_lfht_next calls using the - * node returned by a previous cds_lfht_next. - * Call with rcu_read_lock held. - * Threads calling this API need to be registered RCU read-side threads. - * This function acts as a rcu_dereference() to read the node pointer. - */ -void cds_lfht_next_duplicate(struct cds_lfht *ht, - cds_lfht_match_fct match, const void *key, - struct cds_lfht_iter *iter); - -/* - * cds_lfht_first - get the first node in the table. - * @ht: the hash table. - * @iter: First node, if exists (output). *iter->node set to NULL if not found. - * - * Output in "*iter". *iter->node set to NULL if table is empty. - * Call with rcu_read_lock held. - * Threads calling this API need to be registered RCU read-side threads. - * This function acts as a rcu_dereference() to read the node pointer. - */ -void cds_lfht_first(struct cds_lfht *ht, struct cds_lfht_iter *iter); - -/* - * cds_lfht_next - get the next node in the table. - * @ht: the hash table. - * @iter: input: current iterator. - * output: next node, if exists. *iter->node set to NULL if not found. - * - * Input/Output in "*iter". *iter->node set to NULL if *iter was - * pointing to the last table node. - * Call with rcu_read_lock held. - * Threads calling this API need to be registered RCU read-side threads. - * This function acts as a rcu_dereference() to read the node pointer. - */ -void cds_lfht_next(struct cds_lfht *ht, struct cds_lfht_iter *iter); - -/* - * cds_lfht_add - add a node to the hash table. - * @ht: the hash table. - * @hash: the key hash. - * @node: the node to add. - * - * This function supports adding redundant keys into the table. - * Call with rcu_read_lock held. - * Threads calling this API need to be registered RCU read-side threads. - * This function issues a full memory barrier before and after its - * atomic commit. - */ -void cds_lfht_add(struct cds_lfht *ht, unsigned long hash, - struct cds_lfht_node *node); - -/* - * cds_lfht_add_unique - add a node to hash table, if key is not present. - * @ht: the hash table. - * @hash: the node's hash. - * @match: the key match function. - * @key: the node's key. - * @node: the node to try adding. - * - * Return the node added upon success. - * Return the unique node already present upon failure. If - * cds_lfht_add_unique fails, the node passed as parameter should be - * freed by the caller. In this case, the caller does NOT need to wait - * for a grace period before freeing the node. - * Call with rcu_read_lock held. - * Threads calling this API need to be registered RCU read-side threads. - * - * The semantic of this function is that if only this function is used - * to add keys into the table, no duplicated keys should ever be - * observable in the table. The same guarantee apply for combination of - * add_unique and add_replace (see below). - * - * Upon success, this function issues a full memory barrier before and - * after its atomic commit. Upon failure, this function acts like a - * simple lookup operation: it acts as a rcu_dereference() to read the - * node pointer. The failure case does not guarantee any other memory - * barrier. - */ -struct cds_lfht_node *cds_lfht_add_unique(struct cds_lfht *ht, - unsigned long hash, - cds_lfht_match_fct match, - const void *key, - struct cds_lfht_node *node); - -/* - * cds_lfht_add_replace - replace or add a node within hash table. - * @ht: the hash table. - * @hash: the node's hash. - * @match: the key match function. - * @key: the node's key. - * @node: the node to add. - * - * Return the node replaced upon success. If no node matching the key - * was present, return NULL, which also means the operation succeeded. - * This replacement operation should never fail. - * Call with rcu_read_lock held. - * Threads calling this API need to be registered RCU read-side threads. - * After successful replacement, a grace period must be waited for before - * freeing the memory reserved for the returned node. - * - * The semantic of replacement vs lookups and traversals is the - * following: if lookups and traversals are performed between a key - * unique insertion and its removal, we guarantee that the lookups and - * traversals will always find exactly one instance of the key if it is - * replaced concurrently with the lookups. - * - * Providing this semantic allows us to ensure that replacement-only - * schemes will never generate duplicated keys. It also allows us to - * guarantee that a combination of add_replace and add_unique updates - * will never generate duplicated keys. - * - * This function issues a full memory barrier before and after its - * atomic commit. - */ -struct cds_lfht_node *cds_lfht_add_replace(struct cds_lfht *ht, - unsigned long hash, - cds_lfht_match_fct match, - const void *key, - struct cds_lfht_node *node); - -/* - * cds_lfht_replace - replace a node pointed to by iter within hash table. - * @ht: the hash table. - * @old_iter: the iterator position of the node to replace. - * @hash: the node's hash. - * @match: the key match function. - * @key: the node's key. - * @new_node: the new node to use as replacement. - * - * Return 0 if replacement is successful, negative value otherwise. - * Replacing a NULL old node or an already removed node will fail with - * -ENOENT. - * If the hash or value of the node to replace and the new node differ, - * this function returns -EINVAL without proceeding to the replacement. - * Old node can be looked up with cds_lfht_lookup and cds_lfht_next. - * RCU read-side lock must be held between lookup and replacement. - * Call with rcu_read_lock held. - * Threads calling this API need to be registered RCU read-side threads. - * After successful replacement, a grace period must be waited for before - * freeing the memory reserved for the old node (which can be accessed - * with cds_lfht_iter_get_node). - * - * The semantic of replacement vs lookups is the same as - * cds_lfht_add_replace(). - * - * Upon success, this function issues a full memory barrier before and - * after its atomic commit. Upon failure, this function does not issue - * any memory barrier. - */ -int cds_lfht_replace(struct cds_lfht *ht, - struct cds_lfht_iter *old_iter, - unsigned long hash, - cds_lfht_match_fct match, - const void *key, - struct cds_lfht_node *new_node); - -/* - * cds_lfht_del - remove node pointed to by iterator from hash table. - * @ht: the hash table. - * @node: the node to delete. - * - * Return 0 if the node is successfully removed, negative value - * otherwise. - * Deleting a NULL node or an already removed node will fail with a - * negative value. - * Node can be looked up with cds_lfht_lookup and cds_lfht_next, - * followed by use of cds_lfht_iter_get_node. - * RCU read-side lock must be held between lookup and removal. - * Call with rcu_read_lock held. - * Threads calling this API need to be registered RCU read-side threads. - * After successful removal, a grace period must be waited for before - * freeing the memory reserved for old node (which can be accessed with - * cds_lfht_iter_get_node). - * Upon success, this function issues a full memory barrier before and - * after its atomic commit. Upon failure, this function does not issue - * any memory barrier. - */ -int cds_lfht_del(struct cds_lfht *ht, struct cds_lfht_node *node); - -/* - * cds_lfht_is_node_deleted - query whether a node is removed from hash table. - * - * Return non-zero if the node is deleted from the hash table, 0 - * otherwise. - * Node can be looked up with cds_lfht_lookup and cds_lfht_next, - * followed by use of cds_lfht_iter_get_node. - * RCU read-side lock must be held between lookup and call to this - * function. - * Call with rcu_read_lock held. - * Threads calling this API need to be registered RCU read-side threads. - * This function does not issue any memory barrier. - */ -int cds_lfht_is_node_deleted(struct cds_lfht_node *node); - -/* - * cds_lfht_resize - Force a hash table resize - * @ht: the hash table. - * @new_size: update to this hash table size. - * - * Threads calling this API need to be registered RCU read-side threads. - * This function does not (necessarily) issue memory barriers. - * cds_lfht_resize should *not* be called from a RCU read-side critical - * section. - */ -void cds_lfht_resize(struct cds_lfht *ht, unsigned long new_size); - -/* - * Note: it is safe to perform element removal (del), replacement, or - * any hash table update operation during any of the following hash - * table traversals. - * These functions act as rcu_dereference() to read the node pointers. - */ -#define cds_lfht_for_each(ht, iter, node) \ - for (cds_lfht_first(ht, iter), \ - node = cds_lfht_iter_get_node(iter); \ - node != NULL; \ - cds_lfht_next(ht, iter), \ - node = cds_lfht_iter_get_node(iter)) - -#define cds_lfht_for_each_duplicate(ht, hash, match, key, iter, node) \ - for (cds_lfht_lookup(ht, hash, match, key, iter), \ - node = cds_lfht_iter_get_node(iter); \ - node != NULL; \ - cds_lfht_next_duplicate(ht, match, key, iter), \ - node = cds_lfht_iter_get_node(iter)) - -#define cds_lfht_for_each_entry(ht, iter, pos, member) \ - for (cds_lfht_first(ht, iter), \ - pos = caa_container_of(cds_lfht_iter_get_node(iter), \ - __typeof__(*(pos)), member); \ - cds_lfht_iter_get_node(iter) != NULL; \ - cds_lfht_next(ht, iter), \ - pos = caa_container_of(cds_lfht_iter_get_node(iter), \ - __typeof__(*(pos)), member)) - -#define cds_lfht_for_each_entry_duplicate(ht, hash, match, key, \ - iter, pos, member) \ - for (cds_lfht_lookup(ht, hash, match, key, iter), \ - pos = caa_container_of(cds_lfht_iter_get_node(iter), \ - __typeof__(*(pos)), member); \ - cds_lfht_iter_get_node(iter) != NULL; \ - cds_lfht_next_duplicate(ht, match, key, iter), \ - pos = caa_container_of(cds_lfht_iter_get_node(iter), \ - __typeof__(*(pos)), member)) - -#ifdef __cplusplus -} -#endif - -#endif /* _URCU_RCULFHASH_H */ diff --git a/src/common/hashtable/urcu-flavor.h b/src/common/hashtable/urcu-flavor.h deleted file mode 100644 index 9af4d0e63..000000000 --- a/src/common/hashtable/urcu-flavor.h +++ /dev/null @@ -1,65 +0,0 @@ -#ifndef _URCU_FLAVOR_H -#define _URCU_FLAVOR_H - -/* - * urcu-flavor.h - * - * Userspace RCU header - rcu flavor declarations - * - * Copyright (c) 2011 Lai Jiangshan - * - * 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 - */ - -#ifdef __cplusplus -extern "C" { -#endif - -struct rcu_flavor_struct { - void (*read_lock)(void); - void (*read_unlock)(void); - void (*read_quiescent_state)(void); - void (*update_call_rcu)(struct rcu_head *head, - void (*func)(struct rcu_head *head)); - void (*update_synchronize_rcu)(void); - void (*update_defer_rcu)(void (*fct)(void *p), void *p); - - void (*thread_offline)(void); - void (*thread_online)(void); - void (*register_thread)(void); - void (*unregister_thread)(void); -}; - -#define DEFINE_RCU_FLAVOR(x) \ -const struct rcu_flavor_struct x = { \ - .read_lock = rcu_read_lock, \ - .read_unlock = rcu_read_unlock, \ - .read_quiescent_state = rcu_quiescent_state, \ - .update_call_rcu = call_rcu, \ - .update_synchronize_rcu = synchronize_rcu, \ - .update_defer_rcu = defer_rcu, \ - .thread_offline = rcu_thread_offline, \ - .thread_online = rcu_thread_online, \ - .register_thread = rcu_register_thread, \ - .unregister_thread = rcu_unregister_thread,\ -} - -extern const struct rcu_flavor_struct rcu_flavor; - -#ifdef __cplusplus -} -#endif - -#endif /* _URCU_FLAVOR_H */ -- 2.34.1