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Diffstat (limited to 'module/spl/spl-tsd.c')
| -rw-r--r-- | module/spl/spl-tsd.c | 720 |
1 files changed, 0 insertions, 720 deletions
diff --git a/module/spl/spl-tsd.c b/module/spl/spl-tsd.c deleted file mode 100644 index 14342d5a6..000000000 --- a/module/spl/spl-tsd.c +++ /dev/null @@ -1,720 +0,0 @@ -/* - * Copyright (C) 2010 Lawrence Livermore National Security, LLC. - * Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER). - * Written by Brian Behlendorf <[email protected]>. - * UCRL-CODE-235197 - * - * This file is part of the SPL, Solaris Porting Layer. - * For details, see <http://zfsonlinux.org/>. - * - * The SPL 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. - * - * The SPL 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 the SPL. If not, see <http://www.gnu.org/licenses/>. - * - * - * Solaris Porting Layer (SPL) Thread Specific Data Implementation. - * - * Thread specific data has implemented using a hash table, this avoids - * the need to add a member to the task structure and allows maximum - * portability between kernels. This implementation has been optimized - * to keep the tsd_set() and tsd_get() times as small as possible. - * - * The majority of the entries in the hash table are for specific tsd - * entries. These entries are hashed by the product of their key and - * pid because by design the key and pid are guaranteed to be unique. - * Their product also has the desirable properly that it will be uniformly - * distributed over the hash bins providing neither the pid nor key is zero. - * Under linux the zero pid is always the init process and thus won't be - * used, and this implementation is careful to never to assign a zero key. - * By default the hash table is sized to 512 bins which is expected to - * be sufficient for light to moderate usage of thread specific data. - * - * The hash table contains two additional type of entries. They first - * type is entry is called a 'key' entry and it is added to the hash during - * tsd_create(). It is used to store the address of the destructor function - * and it is used as an anchor point. All tsd entries which use the same - * key will be linked to this entry. This is used during tsd_destroy() to - * quickly call the destructor function for all tsd associated with the key. - * The 'key' entry may be looked up with tsd_hash_search() by passing the - * key you wish to lookup and DTOR_PID constant as the pid. - * - * The second type of entry is called a 'pid' entry and it is added to the - * hash the first time a process set a key. The 'pid' entry is also used - * as an anchor and all tsd for the process will be linked to it. This - * list is using during tsd_exit() to ensure all registered destructors - * are run for the process. The 'pid' entry may be looked up with - * tsd_hash_search() by passing the PID_KEY constant as the key, and - * the process pid. Note that tsd_exit() is called by thread_exit() - * so if your using the Solaris thread API you should not need to call - * tsd_exit() directly. - * - */ - -#include <sys/kmem.h> -#include <sys/thread.h> -#include <sys/tsd.h> -#include <linux/hash.h> - -typedef struct tsd_hash_bin { - spinlock_t hb_lock; - struct hlist_head hb_head; -} tsd_hash_bin_t; - -typedef struct tsd_hash_table { - spinlock_t ht_lock; - uint_t ht_bits; - uint_t ht_key; - tsd_hash_bin_t *ht_bins; -} tsd_hash_table_t; - -typedef struct tsd_hash_entry { - uint_t he_key; - pid_t he_pid; - dtor_func_t he_dtor; - void *he_value; - struct hlist_node he_list; - struct list_head he_key_list; - struct list_head he_pid_list; -} tsd_hash_entry_t; - -static tsd_hash_table_t *tsd_hash_table = NULL; - - -/* - * tsd_hash_search - searches hash table for tsd_hash_entry - * @table: hash table - * @key: search key - * @pid: search pid - */ -static tsd_hash_entry_t * -tsd_hash_search(tsd_hash_table_t *table, uint_t key, pid_t pid) -{ - struct hlist_node *node; - tsd_hash_entry_t *entry; - tsd_hash_bin_t *bin; - ulong_t hash; - - hash = hash_long((ulong_t)key * (ulong_t)pid, table->ht_bits); - bin = &table->ht_bins[hash]; - spin_lock(&bin->hb_lock); - hlist_for_each(node, &bin->hb_head) { - entry = list_entry(node, tsd_hash_entry_t, he_list); - if ((entry->he_key == key) && (entry->he_pid == pid)) { - spin_unlock(&bin->hb_lock); - return (entry); - } - } - - spin_unlock(&bin->hb_lock); - return (NULL); -} - -/* - * tsd_hash_dtor - call the destructor and free all entries on the list - * @work: list of hash entries - * - * For a list of entries which have all already been removed from the - * hash call their registered destructor then free the associated memory. - */ -static void -tsd_hash_dtor(struct hlist_head *work) -{ - tsd_hash_entry_t *entry; - - while (!hlist_empty(work)) { - entry = hlist_entry(work->first, tsd_hash_entry_t, he_list); - hlist_del(&entry->he_list); - - if (entry->he_dtor && entry->he_pid != DTOR_PID) - entry->he_dtor(entry->he_value); - - kmem_free(entry, sizeof (tsd_hash_entry_t)); - } -} - -/* - * tsd_hash_add - adds an entry to hash table - * @table: hash table - * @key: search key - * @pid: search pid - * - * The caller is responsible for ensuring the unique key/pid do not - * already exist in the hash table. This possible because all entries - * are thread specific thus a concurrent thread will never attempt to - * add this key/pid. Because multiple bins must be checked to add - * links to the dtor and pid entries the entire table is locked. - */ -static int -tsd_hash_add(tsd_hash_table_t *table, uint_t key, pid_t pid, void *value) -{ - tsd_hash_entry_t *entry, *dtor_entry, *pid_entry; - tsd_hash_bin_t *bin; - ulong_t hash; - int rc = 0; - - ASSERT3P(tsd_hash_search(table, key, pid), ==, NULL); - - /* New entry allocate structure, set value, and add to hash */ - entry = kmem_alloc(sizeof (tsd_hash_entry_t), KM_PUSHPAGE); - if (entry == NULL) - return (ENOMEM); - - entry->he_key = key; - entry->he_pid = pid; - entry->he_value = value; - INIT_HLIST_NODE(&entry->he_list); - INIT_LIST_HEAD(&entry->he_key_list); - INIT_LIST_HEAD(&entry->he_pid_list); - - spin_lock(&table->ht_lock); - - /* Destructor entry must exist for all valid keys */ - dtor_entry = tsd_hash_search(table, entry->he_key, DTOR_PID); - ASSERT3P(dtor_entry, !=, NULL); - entry->he_dtor = dtor_entry->he_dtor; - - /* Process entry must exist for all valid processes */ - pid_entry = tsd_hash_search(table, PID_KEY, entry->he_pid); - ASSERT3P(pid_entry, !=, NULL); - - hash = hash_long((ulong_t)key * (ulong_t)pid, table->ht_bits); - bin = &table->ht_bins[hash]; - spin_lock(&bin->hb_lock); - - /* Add to the hash, key, and pid lists */ - hlist_add_head(&entry->he_list, &bin->hb_head); - list_add(&entry->he_key_list, &dtor_entry->he_key_list); - list_add(&entry->he_pid_list, &pid_entry->he_pid_list); - - spin_unlock(&bin->hb_lock); - spin_unlock(&table->ht_lock); - - return (rc); -} - -/* - * tsd_hash_add_key - adds a destructor entry to the hash table - * @table: hash table - * @keyp: search key - * @dtor: key destructor - * - * For every unique key there is a single entry in the hash which is used - * as anchor. All other thread specific entries for this key are linked - * to this anchor via the 'he_key_list' list head. On return they keyp - * will be set to the next available key for the hash table. - */ -static int -tsd_hash_add_key(tsd_hash_table_t *table, uint_t *keyp, dtor_func_t dtor) -{ - tsd_hash_entry_t *tmp_entry, *entry; - tsd_hash_bin_t *bin; - ulong_t hash; - int keys_checked = 0; - - ASSERT3P(table, !=, NULL); - - /* Allocate entry to be used as a destructor for this key */ - entry = kmem_alloc(sizeof (tsd_hash_entry_t), KM_PUSHPAGE); - if (entry == NULL) - return (ENOMEM); - - /* Determine next available key value */ - spin_lock(&table->ht_lock); - do { - /* Limited to TSD_KEYS_MAX concurrent unique keys */ - if (table->ht_key++ > TSD_KEYS_MAX) - table->ht_key = 1; - - /* Ensure failure when all TSD_KEYS_MAX keys are in use */ - if (keys_checked++ >= TSD_KEYS_MAX) { - spin_unlock(&table->ht_lock); - return (ENOENT); - } - - tmp_entry = tsd_hash_search(table, table->ht_key, DTOR_PID); - } while (tmp_entry); - - /* Add destructor entry in to hash table */ - entry->he_key = *keyp = table->ht_key; - entry->he_pid = DTOR_PID; - entry->he_dtor = dtor; - entry->he_value = NULL; - INIT_HLIST_NODE(&entry->he_list); - INIT_LIST_HEAD(&entry->he_key_list); - INIT_LIST_HEAD(&entry->he_pid_list); - - hash = hash_long((ulong_t)*keyp * (ulong_t)DTOR_PID, table->ht_bits); - bin = &table->ht_bins[hash]; - spin_lock(&bin->hb_lock); - - hlist_add_head(&entry->he_list, &bin->hb_head); - - spin_unlock(&bin->hb_lock); - spin_unlock(&table->ht_lock); - - return (0); -} - -/* - * tsd_hash_add_pid - adds a process entry to the hash table - * @table: hash table - * @pid: search pid - * - * For every process there is a single entry in the hash which is used - * as anchor. All other thread specific entries for this process are - * linked to this anchor via the 'he_pid_list' list head. - */ -static int -tsd_hash_add_pid(tsd_hash_table_t *table, pid_t pid) -{ - tsd_hash_entry_t *entry; - tsd_hash_bin_t *bin; - ulong_t hash; - - /* Allocate entry to be used as the process reference */ - entry = kmem_alloc(sizeof (tsd_hash_entry_t), KM_PUSHPAGE); - if (entry == NULL) - return (ENOMEM); - - spin_lock(&table->ht_lock); - entry->he_key = PID_KEY; - entry->he_pid = pid; - entry->he_dtor = NULL; - entry->he_value = NULL; - INIT_HLIST_NODE(&entry->he_list); - INIT_LIST_HEAD(&entry->he_key_list); - INIT_LIST_HEAD(&entry->he_pid_list); - - hash = hash_long((ulong_t)PID_KEY * (ulong_t)pid, table->ht_bits); - bin = &table->ht_bins[hash]; - spin_lock(&bin->hb_lock); - - hlist_add_head(&entry->he_list, &bin->hb_head); - - spin_unlock(&bin->hb_lock); - spin_unlock(&table->ht_lock); - - return (0); -} - -/* - * tsd_hash_del - delete an entry from hash table, key, and pid lists - * @table: hash table - * @key: search key - * @pid: search pid - */ -static void -tsd_hash_del(tsd_hash_table_t *table, tsd_hash_entry_t *entry) -{ - hlist_del(&entry->he_list); - list_del_init(&entry->he_key_list); - list_del_init(&entry->he_pid_list); -} - -/* - * tsd_hash_table_init - allocate a hash table - * @bits: hash table size - * - * A hash table with 2^bits bins will be created, it may not be resized - * after the fact and must be free'd with tsd_hash_table_fini(). - */ -static tsd_hash_table_t * -tsd_hash_table_init(uint_t bits) -{ - tsd_hash_table_t *table; - int hash, size = (1 << bits); - - table = kmem_zalloc(sizeof (tsd_hash_table_t), KM_SLEEP); - if (table == NULL) - return (NULL); - - table->ht_bins = kmem_zalloc(sizeof (tsd_hash_bin_t) * size, KM_SLEEP); - if (table->ht_bins == NULL) { - kmem_free(table, sizeof (tsd_hash_table_t)); - return (NULL); - } - - for (hash = 0; hash < size; hash++) { - spin_lock_init(&table->ht_bins[hash].hb_lock); - INIT_HLIST_HEAD(&table->ht_bins[hash].hb_head); - } - - spin_lock_init(&table->ht_lock); - table->ht_bits = bits; - table->ht_key = 1; - - return (table); -} - -/* - * tsd_hash_table_fini - free a hash table - * @table: hash table - * - * Free a hash table allocated by tsd_hash_table_init(). If the hash - * table is not empty this function will call the proper destructor for - * all remaining entries before freeing the memory used by those entries. - */ -static void -tsd_hash_table_fini(tsd_hash_table_t *table) -{ - HLIST_HEAD(work); - tsd_hash_bin_t *bin; - tsd_hash_entry_t *entry; - int size, i; - - ASSERT3P(table, !=, NULL); - spin_lock(&table->ht_lock); - for (i = 0, size = (1 << table->ht_bits); i < size; i++) { - bin = &table->ht_bins[i]; - spin_lock(&bin->hb_lock); - while (!hlist_empty(&bin->hb_head)) { - entry = hlist_entry(bin->hb_head.first, - tsd_hash_entry_t, he_list); - tsd_hash_del(table, entry); - hlist_add_head(&entry->he_list, &work); - } - spin_unlock(&bin->hb_lock); - } - spin_unlock(&table->ht_lock); - - tsd_hash_dtor(&work); - kmem_free(table->ht_bins, sizeof (tsd_hash_bin_t)*(1<<table->ht_bits)); - kmem_free(table, sizeof (tsd_hash_table_t)); -} - -/* - * tsd_remove_entry - remove a tsd entry for this thread - * @entry: entry to remove - * - * Remove the thread specific data @entry for this thread. - * If this is the last entry for this thread, also remove the PID entry. - */ -static void -tsd_remove_entry(tsd_hash_entry_t *entry) -{ - HLIST_HEAD(work); - tsd_hash_table_t *table; - tsd_hash_entry_t *pid_entry; - tsd_hash_bin_t *pid_entry_bin, *entry_bin; - ulong_t hash; - - table = tsd_hash_table; - ASSERT3P(table, !=, NULL); - ASSERT3P(entry, !=, NULL); - - spin_lock(&table->ht_lock); - - hash = hash_long((ulong_t)entry->he_key * - (ulong_t)entry->he_pid, table->ht_bits); - entry_bin = &table->ht_bins[hash]; - - /* save the possible pid_entry */ - pid_entry = list_entry(entry->he_pid_list.next, tsd_hash_entry_t, - he_pid_list); - - /* remove entry */ - spin_lock(&entry_bin->hb_lock); - tsd_hash_del(table, entry); - hlist_add_head(&entry->he_list, &work); - spin_unlock(&entry_bin->hb_lock); - - /* if pid_entry is indeed pid_entry, then remove it if it's empty */ - if (pid_entry->he_key == PID_KEY && - list_empty(&pid_entry->he_pid_list)) { - hash = hash_long((ulong_t)pid_entry->he_key * - (ulong_t)pid_entry->he_pid, table->ht_bits); - pid_entry_bin = &table->ht_bins[hash]; - - spin_lock(&pid_entry_bin->hb_lock); - tsd_hash_del(table, pid_entry); - hlist_add_head(&pid_entry->he_list, &work); - spin_unlock(&pid_entry_bin->hb_lock); - } - - spin_unlock(&table->ht_lock); - - tsd_hash_dtor(&work); -} - -/* - * tsd_set - set thread specific data - * @key: lookup key - * @value: value to set - * - * Caller must prevent racing tsd_create() or tsd_destroy(), protected - * from racing tsd_get() or tsd_set() because it is thread specific. - * This function has been optimized to be fast for the update case. - * When setting the tsd initially it will be slower due to additional - * required locking and potential memory allocations. - */ -int -tsd_set(uint_t key, void *value) -{ - tsd_hash_table_t *table; - tsd_hash_entry_t *entry; - pid_t pid; - int rc; - /* mark remove if value is NULL */ - boolean_t remove = (value == NULL); - - table = tsd_hash_table; - pid = curthread->pid; - ASSERT3P(table, !=, NULL); - - if ((key == 0) || (key > TSD_KEYS_MAX)) - return (EINVAL); - - /* Entry already exists in hash table update value */ - entry = tsd_hash_search(table, key, pid); - if (entry) { - entry->he_value = value; - /* remove the entry */ - if (remove) - tsd_remove_entry(entry); - return (0); - } - - /* don't create entry if value is NULL */ - if (remove) - return (0); - - /* Add a process entry to the hash if not yet exists */ - entry = tsd_hash_search(table, PID_KEY, pid); - if (entry == NULL) { - rc = tsd_hash_add_pid(table, pid); - if (rc) - return (rc); - } - - rc = tsd_hash_add(table, key, pid, value); - return (rc); -} -EXPORT_SYMBOL(tsd_set); - -/* - * tsd_get - get thread specific data - * @key: lookup key - * - * Caller must prevent racing tsd_create() or tsd_destroy(). This - * implementation is designed to be fast and scalable, it does not - * lock the entire table only a single hash bin. - */ -void * -tsd_get(uint_t key) -{ - tsd_hash_entry_t *entry; - - ASSERT3P(tsd_hash_table, !=, NULL); - - if ((key == 0) || (key > TSD_KEYS_MAX)) - return (NULL); - - entry = tsd_hash_search(tsd_hash_table, key, curthread->pid); - if (entry == NULL) - return (NULL); - - return (entry->he_value); -} -EXPORT_SYMBOL(tsd_get); - -/* - * tsd_get_by_thread - get thread specific data for specified thread - * @key: lookup key - * @thread: thread to lookup - * - * Caller must prevent racing tsd_create() or tsd_destroy(). This - * implementation is designed to be fast and scalable, it does not - * lock the entire table only a single hash bin. - */ -void * -tsd_get_by_thread(uint_t key, kthread_t *thread) -{ - tsd_hash_entry_t *entry; - - ASSERT3P(tsd_hash_table, !=, NULL); - - if ((key == 0) || (key > TSD_KEYS_MAX)) - return (NULL); - - entry = tsd_hash_search(tsd_hash_table, key, thread->pid); - if (entry == NULL) - return (NULL); - - return (entry->he_value); -} -EXPORT_SYMBOL(tsd_get_by_thread); - -/* - * tsd_create - create thread specific data key - * @keyp: lookup key address - * @dtor: destructor called during tsd_destroy() or tsd_exit() - * - * Provided key must be set to 0 or it assumed to be already in use. - * The dtor is allowed to be NULL in which case no additional cleanup - * for the data is performed during tsd_destroy() or tsd_exit(). - * - * Caller must prevent racing tsd_set() or tsd_get(), this function is - * safe from racing tsd_create(), tsd_destroy(), and tsd_exit(). - */ -void -tsd_create(uint_t *keyp, dtor_func_t dtor) -{ - ASSERT3P(keyp, !=, NULL); - if (*keyp) - return; - - (void) tsd_hash_add_key(tsd_hash_table, keyp, dtor); -} -EXPORT_SYMBOL(tsd_create); - -/* - * tsd_destroy - destroy thread specific data - * @keyp: lookup key address - * - * Destroys the thread specific data on all threads which use this key. - * - * Caller must prevent racing tsd_set() or tsd_get(), this function is - * safe from racing tsd_create(), tsd_destroy(), and tsd_exit(). - */ -void -tsd_destroy(uint_t *keyp) -{ - HLIST_HEAD(work); - tsd_hash_table_t *table; - tsd_hash_entry_t *dtor_entry, *entry; - tsd_hash_bin_t *dtor_entry_bin, *entry_bin; - ulong_t hash; - - table = tsd_hash_table; - ASSERT3P(table, !=, NULL); - - spin_lock(&table->ht_lock); - dtor_entry = tsd_hash_search(table, *keyp, DTOR_PID); - if (dtor_entry == NULL) { - spin_unlock(&table->ht_lock); - return; - } - - /* - * All threads which use this key must be linked off of the - * DTOR_PID entry. They are removed from the hash table and - * linked in to a private working list to be destroyed. - */ - while (!list_empty(&dtor_entry->he_key_list)) { - entry = list_entry(dtor_entry->he_key_list.next, - tsd_hash_entry_t, he_key_list); - ASSERT3U(dtor_entry->he_key, ==, entry->he_key); - ASSERT3P(dtor_entry->he_dtor, ==, entry->he_dtor); - - hash = hash_long((ulong_t)entry->he_key * - (ulong_t)entry->he_pid, table->ht_bits); - entry_bin = &table->ht_bins[hash]; - - spin_lock(&entry_bin->hb_lock); - tsd_hash_del(table, entry); - hlist_add_head(&entry->he_list, &work); - spin_unlock(&entry_bin->hb_lock); - } - - hash = hash_long((ulong_t)dtor_entry->he_key * - (ulong_t)dtor_entry->he_pid, table->ht_bits); - dtor_entry_bin = &table->ht_bins[hash]; - - spin_lock(&dtor_entry_bin->hb_lock); - tsd_hash_del(table, dtor_entry); - hlist_add_head(&dtor_entry->he_list, &work); - spin_unlock(&dtor_entry_bin->hb_lock); - spin_unlock(&table->ht_lock); - - tsd_hash_dtor(&work); - *keyp = 0; -} -EXPORT_SYMBOL(tsd_destroy); - -/* - * tsd_exit - destroys all thread specific data for this thread - * - * Destroys all the thread specific data for this thread. - * - * Caller must prevent racing tsd_set() or tsd_get(), this function is - * safe from racing tsd_create(), tsd_destroy(), and tsd_exit(). - */ -void -tsd_exit(void) -{ - HLIST_HEAD(work); - tsd_hash_table_t *table; - tsd_hash_entry_t *pid_entry, *entry; - tsd_hash_bin_t *pid_entry_bin, *entry_bin; - ulong_t hash; - - table = tsd_hash_table; - ASSERT3P(table, !=, NULL); - - spin_lock(&table->ht_lock); - pid_entry = tsd_hash_search(table, PID_KEY, curthread->pid); - if (pid_entry == NULL) { - spin_unlock(&table->ht_lock); - return; - } - - /* - * All keys associated with this pid must be linked off of the - * PID_KEY entry. They are removed from the hash table and - * linked in to a private working list to be destroyed. - */ - - while (!list_empty(&pid_entry->he_pid_list)) { - entry = list_entry(pid_entry->he_pid_list.next, - tsd_hash_entry_t, he_pid_list); - ASSERT3U(pid_entry->he_pid, ==, entry->he_pid); - - hash = hash_long((ulong_t)entry->he_key * - (ulong_t)entry->he_pid, table->ht_bits); - entry_bin = &table->ht_bins[hash]; - - spin_lock(&entry_bin->hb_lock); - tsd_hash_del(table, entry); - hlist_add_head(&entry->he_list, &work); - spin_unlock(&entry_bin->hb_lock); - } - - hash = hash_long((ulong_t)pid_entry->he_key * - (ulong_t)pid_entry->he_pid, table->ht_bits); - pid_entry_bin = &table->ht_bins[hash]; - - spin_lock(&pid_entry_bin->hb_lock); - tsd_hash_del(table, pid_entry); - hlist_add_head(&pid_entry->he_list, &work); - spin_unlock(&pid_entry_bin->hb_lock); - spin_unlock(&table->ht_lock); - - tsd_hash_dtor(&work); -} -EXPORT_SYMBOL(tsd_exit); - -int -spl_tsd_init(void) -{ - tsd_hash_table = tsd_hash_table_init(TSD_HASH_TABLE_BITS_DEFAULT); - if (tsd_hash_table == NULL) - return (1); - - return (0); -} - -void -spl_tsd_fini(void) -{ - tsd_hash_table_fini(tsd_hash_table); - tsd_hash_table = NULL; -} |