From: Mathieu Desnoyers Date: Sat, 2 Jul 2011 15:24:18 +0000 (-0400) Subject: Merge branch 'master' into urcu/ht X-Git-Tag: v0.7.0~43^2~235 X-Git-Url: https://git.lttng.org/?p=urcu.git;a=commitdiff_plain;h=bc2433a9853a945a825c244e9ccfe341b73b2ceb;hp=c5f52d0c6b1890f0c66f172665ae6793634f5287 Merge branch 'master' into urcu/ht Conflicts: Makefile.inc tests/Makefile.inc urcu-defer.h --- diff --git a/tests/test_ht.c b/tests/test_ht.c new file mode 100644 index 0000000..cdc78d5 --- /dev/null +++ b/tests/test_ht.c @@ -0,0 +1,456 @@ +/* + * test_ht.c + * + * Userspace RCU library - test program + * + * Copyright February 2009 - Mathieu Desnoyers + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program 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 General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +#define _GNU_SOURCE +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "../arch.h" + +#define HASH_SIZE 32 +#define RAND_POOL 1000 + +/* Make this big enough to include the POWER5+ L3 cacheline size of 256B */ +#define CACHE_LINE_SIZE 4096 + +/* hardcoded number of CPUs */ +#define NR_CPUS 16384 + +#if defined(_syscall0) +_syscall0(pid_t, gettid) +#elif defined(__NR_gettid) +static inline pid_t gettid(void) +{ + return syscall(__NR_gettid); +} +#else +#warning "use pid as tid" +static inline pid_t gettid(void) +{ + return getpid(); +} +#endif + +#ifndef DYNAMIC_LINK_TEST +#define _LGPL_SOURCE +#else +#define debug_yield_read() +#endif +#include "../urcu.h" + +static unsigned int __thread rand_lookup; +static unsigned long __thread nr_add; +static unsigned long __thread nr_addexist; +static unsigned long __thread nr_del; +static unsigned long __thread nr_delnoent; +static unsigned long __thread lookup_fail; +static unsigned long __thread lookup_ok; + +static struct rcu_ht *test_ht; + +struct test_data { + int a; + int b; +}; + +static volatile int test_go, test_stop; + +static unsigned long wdelay; + +static unsigned long duration; + +/* read-side C.S. duration, in loops */ +static unsigned long rduration; + +static inline void loop_sleep(unsigned long l) +{ + while(l-- != 0) + cpu_relax(); +} + +static int verbose_mode; + +#define printf_verbose(fmt, args...) \ + do { \ + if (verbose_mode) \ + printf(fmt, args); \ + } while (0) + +static unsigned int cpu_affinities[NR_CPUS]; +static unsigned int next_aff = 0; +static int use_affinity = 0; + +pthread_mutex_t affinity_mutex = PTHREAD_MUTEX_INITIALIZER; + +static void set_affinity(void) +{ + cpu_set_t mask; + int cpu; + int ret; + + if (!use_affinity) + return; + + ret = pthread_mutex_lock(&affinity_mutex); + if (ret) { + perror("Error in pthread mutex lock"); + exit(-1); + } + cpu = cpu_affinities[next_aff++]; + ret = pthread_mutex_unlock(&affinity_mutex); + if (ret) { + perror("Error in pthread mutex unlock"); + exit(-1); + } + CPU_ZERO(&mask); + CPU_SET(cpu, &mask); + sched_setaffinity(0, sizeof(mask), &mask); +} + +/* + * returns 0 if test should end. + */ +static int test_duration_write(void) +{ + return !test_stop; +} + +static int test_duration_read(void) +{ + return !test_stop; +} + +static unsigned long long __thread nr_writes; +static unsigned long long __thread nr_reads; + +static unsigned int nr_readers; +static unsigned int nr_writers; + +pthread_mutex_t rcu_copy_mutex = PTHREAD_MUTEX_INITIALIZER; + +void rcu_copy_mutex_lock(void) +{ + int ret; + ret = pthread_mutex_lock(&rcu_copy_mutex); + if (ret) { + perror("Error in pthread mutex lock"); + exit(-1); + } +} + +void rcu_copy_mutex_unlock(void) +{ + int ret; + + ret = pthread_mutex_unlock(&rcu_copy_mutex); + if (ret) { + perror("Error in pthread mutex unlock"); + exit(-1); + } +} + +#define ARRAY_POISON 0xDEADBEEF + +void *thr_reader(void *_count) +{ + unsigned long long *count = _count; + struct test_data *local_ptr; + + printf_verbose("thread_begin %s, thread id : %lx, tid %lu\n", + "reader", pthread_self(), (unsigned long)gettid()); + + set_affinity(); + + rcu_register_thread(); + + while (!test_go) + { + } + smp_mb(); + + for (;;) { + rcu_read_lock(); + local_ptr = ht_lookup(test_ht, + (void *)(unsigned long)(rand_r(&rand_lookup) % RAND_POOL)); + if (local_ptr == NULL) + lookup_fail++; + else + lookup_ok++; + debug_yield_read(); + if (unlikely(rduration)) + loop_sleep(rduration); + rcu_read_unlock(); + nr_reads++; + if (unlikely(!test_duration_read())) + break; + } + + rcu_unregister_thread(); + + *count = nr_reads; + printf_verbose("thread_end %s, thread id : %lx, tid %lu\n", + "reader", pthread_self(), (unsigned long)gettid()); + printf_verbose("readid : %lx, lookupfail %lu, lookupok %lu\n", + pthread_self(), lookup_fail, lookup_ok); + return ((void*)1); + +} + +void *thr_writer(void *_count) +{ + unsigned long long *count = _count; + struct test_data *data; + int ret; + + printf_verbose("thread_begin %s, thread id : %lx, tid %lu\n", + "writer", pthread_self(), (unsigned long)gettid()); + + set_affinity(); + + rcu_register_thread(); + rcu_defer_register_thread(); + + while (!test_go) + { + } + smp_mb(); + + for (;;) { + if (rand_r(&rand_lookup) & 1) { + data = malloc(sizeof(struct test_data)); + //rcu_copy_mutex_lock(); + ret = ht_add(test_ht, + (void *)(unsigned long)(rand_r(&rand_lookup) % RAND_POOL), + data); + if (ret == -EEXIST) { + free(data); + nr_addexist++; + } else { + nr_add++; + } + //rcu_copy_mutex_unlock(); + } else { + /* May delete */ + //rcu_copy_mutex_lock(); + ret = ht_delete(test_ht, + (void *)(unsigned long)(rand_r(&rand_lookup) % RAND_POOL)); + if (ret == -ENOENT) + nr_delnoent++; + else + nr_del++; + //rcu_copy_mutex_unlock(); + } + //if (nr_writes % 100000 == 0) { + if (nr_writes % 1000 == 0) { + if (rand_r(&rand_lookup) & 1) { + ht_resize(test_ht, 1); + } else { + ht_resize(test_ht, -1); + } + } + nr_writes++; + if (unlikely(!test_duration_write())) + break; + if (unlikely(wdelay)) + loop_sleep(wdelay); + } + + rcu_defer_unregister_thread(); + rcu_unregister_thread(); + + printf_verbose("thread_end %s, thread id : %lx, tid %lu\n", + "writer", pthread_self(), (unsigned long)gettid()); + printf_verbose("info id %lx: nr_add %lu, nr_addexist %lu, nr_del %lu, " + "nr_delnoent %lu\n", pthread_self(), nr_add, + nr_addexist, nr_del, nr_delnoent); + *count = nr_writes; + return ((void*)2); +} + +void show_usage(int argc, char **argv) +{ + printf("Usage : %s nr_readers nr_writers duration (s)", argv[0]); +#ifdef DEBUG_YIELD + printf(" [-r] [-w] (yield reader and/or writer)"); +#endif + printf(" [-d delay] (writer period (us))"); + printf(" [-c duration] (reader C.S. duration (in loops))"); + printf(" [-v] (verbose output)"); + printf(" [-a cpu#] [-a cpu#]... (affinity)"); + printf("\n"); +} + +int main(int argc, char **argv) +{ + int err; + pthread_t *tid_reader, *tid_writer; + void *tret; + unsigned long long *count_reader, *count_writer; + unsigned long long tot_reads = 0, tot_writes = 0; + int i, a, ret; + + if (argc < 4) { + show_usage(argc, argv); + return -1; + } + + err = sscanf(argv[1], "%u", &nr_readers); + if (err != 1) { + show_usage(argc, argv); + return -1; + } + + err = sscanf(argv[2], "%u", &nr_writers); + if (err != 1) { + show_usage(argc, argv); + return -1; + } + + err = sscanf(argv[3], "%lu", &duration); + if (err != 1) { + show_usage(argc, argv); + return -1; + } + + for (i = 4; i < argc; i++) { + if (argv[i][0] != '-') + continue; + switch (argv[i][1]) { +#ifdef DEBUG_YIELD + case 'r': + yield_active |= YIELD_READ; + break; + case 'w': + yield_active |= YIELD_WRITE; + break; +#endif + case 'a': + if (argc < i + 2) { + show_usage(argc, argv); + return -1; + } + a = atoi(argv[++i]); + cpu_affinities[next_aff++] = a; + use_affinity = 1; + printf_verbose("Adding CPU %d affinity\n", a); + break; + case 'c': + if (argc < i + 2) { + show_usage(argc, argv); + return -1; + } + rduration = atol(argv[++i]); + break; + case 'd': + if (argc < i + 2) { + show_usage(argc, argv); + return -1; + } + wdelay = atol(argv[++i]); + break; + case 'v': + verbose_mode = 1; + break; + } + } + + printf_verbose("running test for %lu seconds, %u readers, %u writers.\n", + duration, nr_readers, nr_writers); + printf_verbose("Writer delay : %lu loops.\n", wdelay); + printf_verbose("Reader duration : %lu loops.\n", rduration); + printf_verbose("thread %-6s, thread id : %lx, tid %lu\n", + "main", pthread_self(), (unsigned long)gettid()); + + tid_reader = malloc(sizeof(*tid_reader) * nr_readers); + tid_writer = malloc(sizeof(*tid_writer) * nr_writers); + count_reader = malloc(sizeof(*count_reader) * nr_readers); + count_writer = malloc(sizeof(*count_writer) * nr_writers); + test_ht = ht_new(ht_jhash, free, HASH_SIZE, sizeof(unsigned long), + 43223455); + next_aff = 0; + + for (i = 0; i < nr_readers; i++) { + err = pthread_create(&tid_reader[i], NULL, thr_reader, + &count_reader[i]); + if (err != 0) + exit(1); + } + for (i = 0; i < nr_writers; i++) { + err = pthread_create(&tid_writer[i], NULL, thr_writer, + &count_writer[i]); + if (err != 0) + exit(1); + } + + smp_mb(); + + test_go = 1; + + sleep(duration); + + test_stop = 1; + + for (i = 0; i < nr_readers; i++) { + err = pthread_join(tid_reader[i], &tret); + if (err != 0) + exit(1); + tot_reads += count_reader[i]; + } + for (i = 0; i < nr_writers; i++) { + err = pthread_join(tid_writer[i], &tret); + if (err != 0) + exit(1); + tot_writes += count_writer[i]; + } + rcu_register_thread(); + rcu_defer_register_thread(); + ret = ht_destroy(test_ht); + rcu_defer_unregister_thread(); + rcu_unregister_thread(); + + printf_verbose("final delete: %d items\n", ret); + printf_verbose("total number of reads : %llu, writes %llu\n", tot_reads, + tot_writes); + printf("SUMMARY %-25s testdur %4lu nr_readers %3u rdur %6lu " + "nr_writers %3u " + "wdelay %6lu nr_reads %12llu nr_writes %12llu nr_ops %12llu\n", + argv[0], duration, nr_readers, rduration, + nr_writers, wdelay, tot_reads, tot_writes, + tot_reads + tot_writes); + free(tid_reader); + free(tid_writer); + free(count_reader); + free(count_writer); + return 0; +} diff --git a/urcu-ht.c b/urcu-ht.c new file mode 100644 index 0000000..b8777ac --- /dev/null +++ b/urcu-ht.c @@ -0,0 +1,485 @@ + +/* + * TODO: keys are currently assumed <= sizeof(void *). Key target never freed. + */ + +#define _LGPL_SOURCE +#include +#include +#include +#include + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* + * Maximum number of hash table buckets: 256M on 64-bit. + * Should take about 512MB max if we assume 1 node per 4 buckets. + */ +#define MAX_HT_BUCKETS ((256 << 10) / sizeof(void *)) + +/* node flags */ +#define NODE_STOLEN (1 << 0) + +struct rcu_ht_node; + +struct rcu_ht_node { + struct rcu_ht_node *next; + void *key; + void *data; + unsigned int flags; +}; + +struct rcu_table { + unsigned long size; + struct rcu_ht_node *tbl[0]; +}; + +struct rcu_ht { + struct rcu_table *t; /* shared */ + ht_hash_fct hash_fct; + void (*free_fct)(void *data); /* fct to free data */ + uint32_t keylen; + uint32_t hashseed; + pthread_mutex_t resize_mutex; /* resize mutex: add/del mutex */ + int resize_ongoing; /* fast-path resize check */ +}; + +struct rcu_ht *ht_new(ht_hash_fct hash_fct, void (*free_fct)(void *data), + unsigned long init_size, uint32_t keylen, + uint32_t hashseed) +{ + struct rcu_ht *ht; + + ht = calloc(1, sizeof(struct rcu_ht)); + ht->hash_fct = hash_fct; + ht->free_fct = free_fct; + ht->keylen = keylen; + ht->hashseed = hashseed; + /* this mutex should not nest in read-side C.S. */ + pthread_mutex_init(&ht->resize_mutex, NULL); + ht->resize_ongoing = 0; /* shared */ + ht->t = calloc(1, sizeof(struct rcu_table) + + (init_size * sizeof(struct rcu_ht_node *))); + ht->t->size = init_size; + return ht; +} + +void *ht_lookup(struct rcu_ht *ht, void *key) +{ + struct rcu_table *t; + unsigned long hash; + struct rcu_ht_node *node; + void *ret; + + rcu_read_lock(); + t = rcu_dereference(ht->t); + smp_read_barrier_depends(); /* read t before size and table */ + hash = ht->hash_fct(key, ht->keylen, ht->hashseed) % t->size; + smp_read_barrier_depends(); /* read size before links */ + node = rcu_dereference(t->tbl[hash]); + for (;;) { + if (likely(!node)) { + ret = NULL; + break; + } + if (node->key == key) { + ret = node->data; + break; + } + node = rcu_dereference(node->next); + } + rcu_read_unlock(); + + return ret; +} + +/* + * Will re-try until either: + * - The key is already there (-EEXIST) + * - We successfully add the key at the head of a table bucket. + */ +int ht_add(struct rcu_ht *ht, void *key, void *data) +{ + struct rcu_ht_node *node, *old_head, *new_head; + struct rcu_table *t; + unsigned long hash; + int ret = 0; + + new_head = calloc(1, sizeof(struct rcu_ht_node)); + new_head->key = key; + new_head->data = data; + new_head->flags = 0; + /* here comes the fun and tricky part. + * Add at the beginning with a cmpxchg. + * Hold a read lock between the moment the first element is read + * and the nodes traversal (to find duplicates). This ensures + * the head pointer has not been reclaimed when cmpxchg is done. + * Always adding at the head ensures that we would have to + * re-try if a new item has been added concurrently. So we ensure that + * we never add duplicates. */ +retry: + rcu_read_lock(); + + if (unlikely(LOAD_SHARED(ht->resize_ongoing))) { + rcu_read_unlock(); + /* + * Wait for resize to complete before continuing. + */ + ret = pthread_mutex_lock(&ht->resize_mutex); + assert(!ret); + ret = pthread_mutex_unlock(&ht->resize_mutex); + assert(!ret); + goto retry; + } + + t = rcu_dereference(ht->t); + /* no read barrier needed, because no concurrency with resize */ + hash = ht->hash_fct(key, ht->keylen, ht->hashseed) % t->size; + + old_head = node = rcu_dereference(t->tbl[hash]); + for (;;) { + if (likely(!node)) { + break; + } + if (node->key == key) { + ret = -EEXIST; + goto end; + } + node = rcu_dereference(node->next); + } + new_head->next = old_head; + if (rcu_cmpxchg_pointer(&t->tbl[hash], old_head, new_head) != old_head) + goto restart; +end: + rcu_read_unlock(); + return ret; + + /* restart loop, release and re-take the read lock to be kind to GP */ +restart: + rcu_read_unlock(); + goto retry; +} + +/* + * Restart until we successfully remove the entry, or no entry is left + * ((void *)(unsigned long)-ENOENT). + * Deal with concurrent stealers by doing an extra verification pass to check + * that no element in the list are still pointing to the element stolen. + * This could happen if two concurrent steal for consecutive objects are + * executed. A pointer to an object being stolen could be saved by the + * concurrent stealer for the previous object. + * Also, given that in this precise scenario, another stealer can also want to + * delete the doubly-referenced object; use a "stolen" flag to let only one + * stealer delete the object. + */ +void *ht_steal(struct rcu_ht *ht, void *key) +{ + struct rcu_ht_node **prev, *node, *del_node = NULL; + struct rcu_table *t; + unsigned long hash; + void *data; + int ret; + +retry: + rcu_read_lock(); + + if (unlikely(LOAD_SHARED(ht->resize_ongoing))) { + rcu_read_unlock(); + /* + * Wait for resize to complete before continuing. + */ + ret = pthread_mutex_lock(&ht->resize_mutex); + assert(!ret); + ret = pthread_mutex_unlock(&ht->resize_mutex); + assert(!ret); + goto retry; + } + + t = rcu_dereference(ht->t); + /* no read barrier needed, because no concurrency with resize */ + hash = ht->hash_fct(key, ht->keylen, ht->hashseed) % t->size; + + prev = &t->tbl[hash]; + node = rcu_dereference(*prev); + for (;;) { + if (likely(!node)) { + if (del_node) { + goto end; + } else { + goto error; + } + } + if (node->key == key) { + break; + } + prev = &node->next; + node = rcu_dereference(*prev); + } + + if (!del_node) { + /* + * Another concurrent thread stole it ? If so, let it deal with + * this. Assume NODE_STOLEN is the only flag. If this changes, + * read flags before cmpxchg. + */ + if (cmpxchg(&node->flags, 0, NODE_STOLEN) != 0) + goto error; + } + + /* Found it ! pointer to object is in "prev" */ + if (rcu_cmpxchg_pointer(prev, node, node->next) == node) + del_node = node; + goto restart; + +end: + /* + * From that point, we own node. Note that there can still be concurrent + * RCU readers using it. We can free it outside of read lock after a GP. + */ + rcu_read_unlock(); + + data = del_node->data; + call_rcu(free, del_node); + return data; + +error: + data = (void *)(unsigned long)-ENOENT; + rcu_read_unlock(); + return data; + + /* restart loop, release and re-take the read lock to be kind to GP */ +restart: + rcu_read_unlock(); + goto retry; +} + +int ht_delete(struct rcu_ht *ht, void *key) +{ + void *data; + + data = ht_steal(ht, key); + if (data && data != (void *)(unsigned long)-ENOENT) { + if (ht->free_fct) + call_rcu(ht->free_fct, data); + return 0; + } else { + return -ENOENT; + } +} + +/* Delete all old elements. Allow concurrent writer accesses. */ +int ht_delete_all(struct rcu_ht *ht) +{ + unsigned long i; + struct rcu_ht_node **prev, *node, *inext; + struct rcu_table *t; + int cnt = 0; + int ret; + + /* + * Mutual exclusion with resize operations, but leave add/steal execute + * concurrently. This is OK because we operate only on the heads. + */ + ret = pthread_mutex_lock(&ht->resize_mutex); + assert(!ret); + + t = rcu_dereference(ht->t); + /* no read barrier needed, because no concurrency with resize */ + for (i = 0; i < t->size; i++) { + rcu_read_lock(); + prev = &t->tbl[i]; + /* + * Cut the head. After that, we own the first element. + */ + node = rcu_xchg_pointer(prev, NULL); + if (!node) { + rcu_read_unlock(); + continue; + } + /* + * We manage a list shared with concurrent writers and readers. + * Note that a concurrent add may or may not be deleted by us, + * depending if it arrives before or after the head is cut. + * "node" points to our first node. Remove first elements + * iteratively. + */ + for (;;) { + inext = NULL; + prev = &node->next; + if (prev) + inext = rcu_xchg_pointer(prev, NULL); + /* + * "node" is the first element of the list we have cut. + * We therefore own it, no concurrent writer may delete + * it. There can only be concurrent lookups. Concurrent + * add can only be done on a bucket head, but we've cut + * it already. inext is also owned by us, because we + * have exchanged it for "NULL". It will therefore be + * safe to use it after a G.P. + */ + rcu_read_unlock(); + if (node->data) + call_rcu(ht->free_fct, node->data); + call_rcu(free, node); + cnt++; + if (likely(!inext)) + break; + rcu_read_lock(); + node = inext; + } + } + + ret = pthread_mutex_unlock(&ht->resize_mutex); + assert(!ret); + return cnt; +} + +/* + * Should only be called when no more concurrent readers nor writers can + * possibly access the table. + */ +int ht_destroy(struct rcu_ht *ht) +{ + int ret; + + ret = ht_delete_all(ht); + free(ht->t); + free(ht); + return ret; +} + +static void ht_resize_grow(struct rcu_ht *ht) +{ + unsigned long i, new_size, old_size; + struct rcu_table *new_t, *old_t; + struct rcu_ht_node *node, *new_node, *tmp; + unsigned long hash; + + old_t = ht->t; + old_size = old_t->size; + + if (old_size == MAX_HT_BUCKETS) + return; + + new_size = old_size << 1; + new_t = calloc(1, sizeof(struct rcu_table) + + (new_size * sizeof(struct rcu_ht_node *))); + new_t->size = new_size; + + for (i = 0; i < old_size; i++) { + /* + * Re-hash each entry, insert in new table. + * It's important that a reader looking for a key _will_ find it + * if it's in the table. + * Copy each node. (just the node, not ->data) + */ + node = old_t->tbl[i]; + while (node) { + hash = ht->hash_fct(node->key, ht->keylen, ht->hashseed) + % new_size; + new_node = malloc(sizeof(struct rcu_ht_node)); + new_node->key = node->key; + new_node->data = node->data; + new_node->flags = node->flags; + new_node->next = new_t->tbl[hash]; /* link to first */ + new_t->tbl[hash] = new_node; /* add to head */ + node = node->next; + } + } + + /* Changing table and size atomically wrt lookups */ + rcu_assign_pointer(ht->t, new_t); + + /* Ensure all concurrent lookups use new size and table */ + synchronize_rcu(); + + for (i = 0; i < old_size; i++) { + node = old_t->tbl[i]; + while (node) { + tmp = node->next; + free(node); + node = tmp; + } + } + free(old_t); +} + +static void ht_resize_shrink(struct rcu_ht *ht) +{ + unsigned long i, new_size; + struct rcu_table *new_t, *old_t; + struct rcu_ht_node **prev, *node; + + old_t = ht->t; + if (old_t->size == 1) + return; + + new_size = old_t->size >> 1; + + for (i = 0; i < new_size; i++) { + /* Link end with first entry of i + new_size */ + prev = &old_t->tbl[i]; + node = *prev; + while (node) { + prev = &node->next; + node = *prev; + } + *prev = old_t->tbl[i + new_size]; + } + smp_wmb(); /* write links before changing size */ + STORE_SHARED(old_t->size, new_size); + + /* Ensure all concurrent lookups use new size */ + synchronize_rcu(); + + new_t = realloc(old_t, sizeof(struct rcu_table) + + (new_size * sizeof(struct rcu_ht_node *))); + /* shrinking, pointers should not move */ + assert(new_t == old_t); +} + +/* + * growth: >0: *2, <0: /2 + */ +void ht_resize(struct rcu_ht *ht, int growth) +{ + int ret; + + ret = pthread_mutex_lock(&ht->resize_mutex); + assert(!ret); + STORE_SHARED(ht->resize_ongoing, 1); + synchronize_rcu(); + /* All add/remove are waiting on the mutex. */ + if (growth > 0) + ht_resize_grow(ht); + else if (growth < 0) + ht_resize_shrink(ht); + smp_mb(); + STORE_SHARED(ht->resize_ongoing, 0); + ret = pthread_mutex_unlock(&ht->resize_mutex); + assert(!ret); +} + +/* + * Expects keys <= than pointer size to be encoded in the pointer itself. + */ +uint32_t ht_jhash(void *key, uint32_t length, uint32_t initval) +{ + uint32_t ret; + void *vkey; + + if (length <= sizeof(void *)) + vkey = &key; + else + vkey = key; + ret = jhash(vkey, length, initval); + return ret; +} diff --git a/urcu-ht.h b/urcu-ht.h new file mode 100644 index 0000000..7e3c36c --- /dev/null +++ b/urcu-ht.h @@ -0,0 +1,38 @@ +#ifndef _URCU_HT_H +#define _URCU_HT_H + +#include + +/* + * Caution ! + * Ensure writer threads are registered as urcu readers and with with + * urcu-defer. + * Ensure reader threads are registered as urcu readers. + */ + +typedef uint32_t (*ht_hash_fct)(void *key, uint32_t length, uint32_t initval); + +/* + * init_size must be power of two. + */ +struct rcu_ht *ht_new(ht_hash_fct hash_fct, void (*free_fct)(void *data), + unsigned long init_size, uint32_t keylen, + uint32_t hashseed); + +int ht_delete_all(struct rcu_ht *ht); + +int ht_destroy(struct rcu_ht *ht); + +void *ht_lookup(struct rcu_ht *ht, void *key); + +int ht_add(struct rcu_ht *ht, void *key, void *data); + +int ht_delete(struct rcu_ht *ht, void *key); + +void *ht_steal(struct rcu_ht *ht, void *key); + +void ht_resize(struct rcu_ht *ht, int growth); + +uint32_t ht_jhash(void *key, uint32_t length, uint32_t initval); + +#endif /* _URCU_HT_H */ diff --git a/urcu/jhash.h b/urcu/jhash.h new file mode 100644 index 0000000..def03b8 --- /dev/null +++ b/urcu/jhash.h @@ -0,0 +1,89 @@ +#ifndef _KCOMPAT_JHASH_H +#define _KCOMPAT_JHASH_H + +/* jhash.h: Jenkins hash support. + * + * Copyright (C) 1996 Bob Jenkins (bob_jenkins@burtleburtle.net) + * + * http://burtleburtle.net/bob/hash/ + * + * These are the credits from Bob's sources: + * + * lookup2.c, by Bob Jenkins, December 1996, Public Domain. + * hash(), hash2(), hash3, and mix() are externally useful functions. + * Routines to test the hash are included if SELF_TEST is defined. + * You can use this free for any purpose. It has no warranty. + * + * Copyright (C) 2003 David S. Miller (davem@redhat.com) + * + * I've modified Bob's hash to be useful in the Linux kernel, and + * any bugs present are surely my fault. -DaveM + */ + +#include + +typedef uint8_t u8; +typedef uint32_t u32; + +/* NOTE: Arguments are modified. */ +#define __jhash_mix(a, b, c) \ +{ \ + a -= b; a -= c; a ^= (c>>13); \ + b -= c; b -= a; b ^= (a<<8); \ + c -= a; c -= b; c ^= (b>>13); \ + a -= b; a -= c; a ^= (c>>12); \ + b -= c; b -= a; b ^= (a<<16); \ + c -= a; c -= b; c ^= (b>>5); \ + a -= b; a -= c; a ^= (c>>3); \ + b -= c; b -= a; b ^= (a<<10); \ + c -= a; c -= b; c ^= (b>>15); \ +} + +/* The golden ration: an arbitrary value */ +#define JHASH_GOLDEN_RATIO 0x9e3779b9 + +/* The most generic version, hashes an arbitrary sequence + * of bytes. No alignment or length assumptions are made about + * the input key. + */ +static inline u32 jhash(const void *key, u32 length, u32 initval) +{ + u32 a, b, c, len; + const u8 *k = key; + + len = length; + a = b = JHASH_GOLDEN_RATIO; + c = initval; + + while (len >= 12) { + a += (k[0] +((u32)k[1]<<8) +((u32)k[2]<<16) +((u32)k[3]<<24)); + b += (k[4] +((u32)k[5]<<8) +((u32)k[6]<<16) +((u32)k[7]<<24)); + c += (k[8] +((u32)k[9]<<8) +((u32)k[10]<<16)+((u32)k[11]<<24)); + + __jhash_mix(a,b,c); + + k += 12; + len -= 12; + } + + c += length; + switch (len) { + case 11: c += ((u32)k[10]<<24); + case 10: c += ((u32)k[9]<<16); + case 9 : c += ((u32)k[8]<<8); + case 8 : b += ((u32)k[7]<<24); + case 7 : b += ((u32)k[6]<<16); + case 6 : b += ((u32)k[5]<<8); + case 5 : b += k[4]; + case 4 : a += ((u32)k[3]<<24); + case 3 : a += ((u32)k[2]<<16); + case 2 : a += ((u32)k[1]<<8); + case 1 : a += k[0]; + }; + + __jhash_mix(a,b,c); + + return c; +} + +#endif /* _KCOMPAT_JHASH_H */