| /* |
| * GPL HEADER START |
| * |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License version 2 only, |
| * as published by the Free Software Foundation. |
| * |
| * 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 version 2 for more details (a copy is included |
| * in the LICENSE file that accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License |
| * version 2 along with this program; If not, see |
| * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf |
| * |
| * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| * CA 95054 USA or visit www.sun.com if you need additional information or |
| * have any questions. |
| * |
| * GPL HEADER END |
| */ |
| /* |
| * Copyright (c) 2009, 2010, Oracle and/or its affiliates. All rights reserved. |
| * Use is subject to license terms. |
| * |
| * Copyright (c) 2011, 2012, Intel Corporation. |
| */ |
| /* |
| * This file is part of Lustre, http://www.lustre.org/ |
| * Lustre is a trademark of Sun Microsystems, Inc. |
| * |
| * libcfs/libcfs/hash.c |
| * |
| * Implement a hash class for hash process in lustre system. |
| * |
| * Author: YuZhangyong <yzy@clusterfs.com> |
| * |
| * 2008-08-15: Brian Behlendorf <behlendorf1@llnl.gov> |
| * - Simplified API and improved documentation |
| * - Added per-hash feature flags: |
| * * CFS_HASH_DEBUG additional validation |
| * * CFS_HASH_REHASH dynamic rehashing |
| * - Added per-hash statistics |
| * - General performance enhancements |
| * |
| * 2009-07-31: Liang Zhen <zhen.liang@sun.com> |
| * - move all stuff to libcfs |
| * - don't allow cur_bits != max_bits without setting of CFS_HASH_REHASH |
| * - ignore hs_rwlock if without CFS_HASH_REHASH setting |
| * - buckets are allocated one by one(instead of contiguous memory), |
| * to avoid unnecessary cacheline conflict |
| * |
| * 2010-03-01: Liang Zhen <zhen.liang@sun.com> |
| * - "bucket" is a group of hlist_head now, user can specify bucket size |
| * by bkt_bits of cfs_hash_create(), all hlist_heads in a bucket share |
| * one lock for reducing memory overhead. |
| * |
| * - support lockless hash, caller will take care of locks: |
| * avoid lock overhead for hash tables that are already protected |
| * by locking in the caller for another reason |
| * |
| * - support both spin_lock/rwlock for bucket: |
| * overhead of spinlock contention is lower than read/write |
| * contention of rwlock, so using spinlock to serialize operations on |
| * bucket is more reasonable for those frequently changed hash tables |
| * |
| * - support one-single lock mode: |
| * one lock to protect all hash operations to avoid overhead of |
| * multiple locks if hash table is always small |
| * |
| * - removed a lot of unnecessary addref & decref on hash element: |
| * addref & decref are atomic operations in many use-cases which |
| * are expensive. |
| * |
| * - support non-blocking cfs_hash_add() and cfs_hash_findadd(): |
| * some lustre use-cases require these functions to be strictly |
| * non-blocking, we need to schedule required rehash on a different |
| * thread on those cases. |
| * |
| * - safer rehash on large hash table |
| * In old implementation, rehash function will exclusively lock the |
| * hash table and finish rehash in one batch, it's dangerous on SMP |
| * system because rehash millions of elements could take long time. |
| * New implemented rehash can release lock and relax CPU in middle |
| * of rehash, it's safe for another thread to search/change on the |
| * hash table even it's in rehasing. |
| * |
| * - support two different refcount modes |
| * . hash table has refcount on element |
| * . hash table doesn't change refcount on adding/removing element |
| * |
| * - support long name hash table (for param-tree) |
| * |
| * - fix a bug for cfs_hash_rehash_key: |
| * in old implementation, cfs_hash_rehash_key could screw up the |
| * hash-table because @key is overwritten without any protection. |
| * Now we need user to define hs_keycpy for those rehash enabled |
| * hash tables, cfs_hash_rehash_key will overwrite hash-key |
| * inside lock by calling hs_keycpy. |
| * |
| * - better hash iteration: |
| * Now we support both locked iteration & lockless iteration of hash |
| * table. Also, user can break the iteration by return 1 in callback. |
| */ |
| |
| #include "../../include/linux/libcfs/libcfs.h" |
| #include <linux/seq_file.h> |
| |
| #if CFS_HASH_DEBUG_LEVEL >= CFS_HASH_DEBUG_1 |
| static unsigned int warn_on_depth = 8; |
| module_param(warn_on_depth, uint, 0644); |
| MODULE_PARM_DESC(warn_on_depth, "warning when hash depth is high."); |
| #endif |
| |
| struct cfs_wi_sched *cfs_sched_rehash; |
| |
| static inline void |
| cfs_hash_nl_lock(union cfs_hash_lock *lock, int exclusive) {} |
| |
| static inline void |
| cfs_hash_nl_unlock(union cfs_hash_lock *lock, int exclusive) {} |
| |
| static inline void |
| cfs_hash_spin_lock(union cfs_hash_lock *lock, int exclusive) |
| { |
| spin_lock(&lock->spin); |
| } |
| |
| static inline void |
| cfs_hash_spin_unlock(union cfs_hash_lock *lock, int exclusive) |
| { |
| spin_unlock(&lock->spin); |
| } |
| |
| static inline void |
| cfs_hash_rw_lock(union cfs_hash_lock *lock, int exclusive) |
| { |
| if (!exclusive) |
| read_lock(&lock->rw); |
| else |
| write_lock(&lock->rw); |
| } |
| |
| static inline void |
| cfs_hash_rw_unlock(union cfs_hash_lock *lock, int exclusive) |
| { |
| if (!exclusive) |
| read_unlock(&lock->rw); |
| else |
| write_unlock(&lock->rw); |
| } |
| |
| /** No lock hash */ |
| static cfs_hash_lock_ops_t cfs_hash_nl_lops = |
| { |
| .hs_lock = cfs_hash_nl_lock, |
| .hs_unlock = cfs_hash_nl_unlock, |
| .hs_bkt_lock = cfs_hash_nl_lock, |
| .hs_bkt_unlock = cfs_hash_nl_unlock, |
| }; |
| |
| /** no bucket lock, one spinlock to protect everything */ |
| static cfs_hash_lock_ops_t cfs_hash_nbl_lops = |
| { |
| .hs_lock = cfs_hash_spin_lock, |
| .hs_unlock = cfs_hash_spin_unlock, |
| .hs_bkt_lock = cfs_hash_nl_lock, |
| .hs_bkt_unlock = cfs_hash_nl_unlock, |
| }; |
| |
| /** spin bucket lock, rehash is enabled */ |
| static cfs_hash_lock_ops_t cfs_hash_bkt_spin_lops = |
| { |
| .hs_lock = cfs_hash_rw_lock, |
| .hs_unlock = cfs_hash_rw_unlock, |
| .hs_bkt_lock = cfs_hash_spin_lock, |
| .hs_bkt_unlock = cfs_hash_spin_unlock, |
| }; |
| |
| /** rw bucket lock, rehash is enabled */ |
| static cfs_hash_lock_ops_t cfs_hash_bkt_rw_lops = |
| { |
| .hs_lock = cfs_hash_rw_lock, |
| .hs_unlock = cfs_hash_rw_unlock, |
| .hs_bkt_lock = cfs_hash_rw_lock, |
| .hs_bkt_unlock = cfs_hash_rw_unlock, |
| }; |
| |
| /** spin bucket lock, rehash is disabled */ |
| static cfs_hash_lock_ops_t cfs_hash_nr_bkt_spin_lops = |
| { |
| .hs_lock = cfs_hash_nl_lock, |
| .hs_unlock = cfs_hash_nl_unlock, |
| .hs_bkt_lock = cfs_hash_spin_lock, |
| .hs_bkt_unlock = cfs_hash_spin_unlock, |
| }; |
| |
| /** rw bucket lock, rehash is disabled */ |
| static cfs_hash_lock_ops_t cfs_hash_nr_bkt_rw_lops = |
| { |
| .hs_lock = cfs_hash_nl_lock, |
| .hs_unlock = cfs_hash_nl_unlock, |
| .hs_bkt_lock = cfs_hash_rw_lock, |
| .hs_bkt_unlock = cfs_hash_rw_unlock, |
| }; |
| |
| static void |
| cfs_hash_lock_setup(struct cfs_hash *hs) |
| { |
| if (cfs_hash_with_no_lock(hs)) { |
| hs->hs_lops = &cfs_hash_nl_lops; |
| |
| } else if (cfs_hash_with_no_bktlock(hs)) { |
| hs->hs_lops = &cfs_hash_nbl_lops; |
| spin_lock_init(&hs->hs_lock.spin); |
| |
| } else if (cfs_hash_with_rehash(hs)) { |
| rwlock_init(&hs->hs_lock.rw); |
| |
| if (cfs_hash_with_rw_bktlock(hs)) |
| hs->hs_lops = &cfs_hash_bkt_rw_lops; |
| else if (cfs_hash_with_spin_bktlock(hs)) |
| hs->hs_lops = &cfs_hash_bkt_spin_lops; |
| else |
| LBUG(); |
| } else { |
| if (cfs_hash_with_rw_bktlock(hs)) |
| hs->hs_lops = &cfs_hash_nr_bkt_rw_lops; |
| else if (cfs_hash_with_spin_bktlock(hs)) |
| hs->hs_lops = &cfs_hash_nr_bkt_spin_lops; |
| else |
| LBUG(); |
| } |
| } |
| |
| /** |
| * Simple hash head without depth tracking |
| * new element is always added to head of hlist |
| */ |
| typedef struct { |
| struct hlist_head hh_head; /**< entries list */ |
| } cfs_hash_head_t; |
| |
| static int |
| cfs_hash_hh_hhead_size(struct cfs_hash *hs) |
| { |
| return sizeof(cfs_hash_head_t); |
| } |
| |
| static struct hlist_head * |
| cfs_hash_hh_hhead(struct cfs_hash *hs, struct cfs_hash_bd *bd) |
| { |
| cfs_hash_head_t *head = (cfs_hash_head_t *)&bd->bd_bucket->hsb_head[0]; |
| |
| return &head[bd->bd_offset].hh_head; |
| } |
| |
| static int |
| cfs_hash_hh_hnode_add(struct cfs_hash *hs, struct cfs_hash_bd *bd, |
| struct hlist_node *hnode) |
| { |
| hlist_add_head(hnode, cfs_hash_hh_hhead(hs, bd)); |
| return -1; /* unknown depth */ |
| } |
| |
| static int |
| cfs_hash_hh_hnode_del(struct cfs_hash *hs, struct cfs_hash_bd *bd, |
| struct hlist_node *hnode) |
| { |
| hlist_del_init(hnode); |
| return -1; /* unknown depth */ |
| } |
| |
| /** |
| * Simple hash head with depth tracking |
| * new element is always added to head of hlist |
| */ |
| typedef struct { |
| struct hlist_head hd_head; /**< entries list */ |
| unsigned int hd_depth; /**< list length */ |
| } cfs_hash_head_dep_t; |
| |
| static int |
| cfs_hash_hd_hhead_size(struct cfs_hash *hs) |
| { |
| return sizeof(cfs_hash_head_dep_t); |
| } |
| |
| static struct hlist_head * |
| cfs_hash_hd_hhead(struct cfs_hash *hs, struct cfs_hash_bd *bd) |
| { |
| cfs_hash_head_dep_t *head; |
| |
| head = (cfs_hash_head_dep_t *)&bd->bd_bucket->hsb_head[0]; |
| return &head[bd->bd_offset].hd_head; |
| } |
| |
| static int |
| cfs_hash_hd_hnode_add(struct cfs_hash *hs, struct cfs_hash_bd *bd, |
| struct hlist_node *hnode) |
| { |
| cfs_hash_head_dep_t *hh = container_of(cfs_hash_hd_hhead(hs, bd), |
| cfs_hash_head_dep_t, hd_head); |
| hlist_add_head(hnode, &hh->hd_head); |
| return ++hh->hd_depth; |
| } |
| |
| static int |
| cfs_hash_hd_hnode_del(struct cfs_hash *hs, struct cfs_hash_bd *bd, |
| struct hlist_node *hnode) |
| { |
| cfs_hash_head_dep_t *hh = container_of(cfs_hash_hd_hhead(hs, bd), |
| cfs_hash_head_dep_t, hd_head); |
| hlist_del_init(hnode); |
| return --hh->hd_depth; |
| } |
| |
| /** |
| * double links hash head without depth tracking |
| * new element is always added to tail of hlist |
| */ |
| typedef struct { |
| struct hlist_head dh_head; /**< entries list */ |
| struct hlist_node *dh_tail; /**< the last entry */ |
| } cfs_hash_dhead_t; |
| |
| static int |
| cfs_hash_dh_hhead_size(struct cfs_hash *hs) |
| { |
| return sizeof(cfs_hash_dhead_t); |
| } |
| |
| static struct hlist_head * |
| cfs_hash_dh_hhead(struct cfs_hash *hs, struct cfs_hash_bd *bd) |
| { |
| cfs_hash_dhead_t *head; |
| |
| head = (cfs_hash_dhead_t *)&bd->bd_bucket->hsb_head[0]; |
| return &head[bd->bd_offset].dh_head; |
| } |
| |
| static int |
| cfs_hash_dh_hnode_add(struct cfs_hash *hs, struct cfs_hash_bd *bd, |
| struct hlist_node *hnode) |
| { |
| cfs_hash_dhead_t *dh = container_of(cfs_hash_dh_hhead(hs, bd), |
| cfs_hash_dhead_t, dh_head); |
| |
| if (dh->dh_tail != NULL) /* not empty */ |
| hlist_add_behind(hnode, dh->dh_tail); |
| else /* empty list */ |
| hlist_add_head(hnode, &dh->dh_head); |
| dh->dh_tail = hnode; |
| return -1; /* unknown depth */ |
| } |
| |
| static int |
| cfs_hash_dh_hnode_del(struct cfs_hash *hs, struct cfs_hash_bd *bd, |
| struct hlist_node *hnd) |
| { |
| cfs_hash_dhead_t *dh = container_of(cfs_hash_dh_hhead(hs, bd), |
| cfs_hash_dhead_t, dh_head); |
| |
| if (hnd->next == NULL) { /* it's the tail */ |
| dh->dh_tail = (hnd->pprev == &dh->dh_head.first) ? NULL : |
| container_of(hnd->pprev, struct hlist_node, next); |
| } |
| hlist_del_init(hnd); |
| return -1; /* unknown depth */ |
| } |
| |
| /** |
| * double links hash head with depth tracking |
| * new element is always added to tail of hlist |
| */ |
| typedef struct { |
| struct hlist_head dd_head; /**< entries list */ |
| struct hlist_node *dd_tail; /**< the last entry */ |
| unsigned int dd_depth; /**< list length */ |
| } cfs_hash_dhead_dep_t; |
| |
| static int |
| cfs_hash_dd_hhead_size(struct cfs_hash *hs) |
| { |
| return sizeof(cfs_hash_dhead_dep_t); |
| } |
| |
| static struct hlist_head * |
| cfs_hash_dd_hhead(struct cfs_hash *hs, struct cfs_hash_bd *bd) |
| { |
| cfs_hash_dhead_dep_t *head; |
| |
| head = (cfs_hash_dhead_dep_t *)&bd->bd_bucket->hsb_head[0]; |
| return &head[bd->bd_offset].dd_head; |
| } |
| |
| static int |
| cfs_hash_dd_hnode_add(struct cfs_hash *hs, struct cfs_hash_bd *bd, |
| struct hlist_node *hnode) |
| { |
| cfs_hash_dhead_dep_t *dh = container_of(cfs_hash_dd_hhead(hs, bd), |
| cfs_hash_dhead_dep_t, dd_head); |
| |
| if (dh->dd_tail != NULL) /* not empty */ |
| hlist_add_behind(hnode, dh->dd_tail); |
| else /* empty list */ |
| hlist_add_head(hnode, &dh->dd_head); |
| dh->dd_tail = hnode; |
| return ++dh->dd_depth; |
| } |
| |
| static int |
| cfs_hash_dd_hnode_del(struct cfs_hash *hs, struct cfs_hash_bd *bd, |
| struct hlist_node *hnd) |
| { |
| cfs_hash_dhead_dep_t *dh = container_of(cfs_hash_dd_hhead(hs, bd), |
| cfs_hash_dhead_dep_t, dd_head); |
| |
| if (hnd->next == NULL) { /* it's the tail */ |
| dh->dd_tail = (hnd->pprev == &dh->dd_head.first) ? NULL : |
| container_of(hnd->pprev, struct hlist_node, next); |
| } |
| hlist_del_init(hnd); |
| return --dh->dd_depth; |
| } |
| |
| static cfs_hash_hlist_ops_t cfs_hash_hh_hops = { |
| .hop_hhead = cfs_hash_hh_hhead, |
| .hop_hhead_size = cfs_hash_hh_hhead_size, |
| .hop_hnode_add = cfs_hash_hh_hnode_add, |
| .hop_hnode_del = cfs_hash_hh_hnode_del, |
| }; |
| |
| static cfs_hash_hlist_ops_t cfs_hash_hd_hops = { |
| .hop_hhead = cfs_hash_hd_hhead, |
| .hop_hhead_size = cfs_hash_hd_hhead_size, |
| .hop_hnode_add = cfs_hash_hd_hnode_add, |
| .hop_hnode_del = cfs_hash_hd_hnode_del, |
| }; |
| |
| static cfs_hash_hlist_ops_t cfs_hash_dh_hops = { |
| .hop_hhead = cfs_hash_dh_hhead, |
| .hop_hhead_size = cfs_hash_dh_hhead_size, |
| .hop_hnode_add = cfs_hash_dh_hnode_add, |
| .hop_hnode_del = cfs_hash_dh_hnode_del, |
| }; |
| |
| static cfs_hash_hlist_ops_t cfs_hash_dd_hops = { |
| .hop_hhead = cfs_hash_dd_hhead, |
| .hop_hhead_size = cfs_hash_dd_hhead_size, |
| .hop_hnode_add = cfs_hash_dd_hnode_add, |
| .hop_hnode_del = cfs_hash_dd_hnode_del, |
| }; |
| |
| static void |
| cfs_hash_hlist_setup(struct cfs_hash *hs) |
| { |
| if (cfs_hash_with_add_tail(hs)) { |
| hs->hs_hops = cfs_hash_with_depth(hs) ? |
| &cfs_hash_dd_hops : &cfs_hash_dh_hops; |
| } else { |
| hs->hs_hops = cfs_hash_with_depth(hs) ? |
| &cfs_hash_hd_hops : &cfs_hash_hh_hops; |
| } |
| } |
| |
| static void |
| cfs_hash_bd_from_key(struct cfs_hash *hs, struct cfs_hash_bucket **bkts, |
| unsigned int bits, const void *key, struct cfs_hash_bd *bd) |
| { |
| unsigned int index = cfs_hash_id(hs, key, (1U << bits) - 1); |
| |
| LASSERT(bits == hs->hs_cur_bits || bits == hs->hs_rehash_bits); |
| |
| bd->bd_bucket = bkts[index & ((1U << (bits - hs->hs_bkt_bits)) - 1)]; |
| bd->bd_offset = index >> (bits - hs->hs_bkt_bits); |
| } |
| |
| void |
| cfs_hash_bd_get(struct cfs_hash *hs, const void *key, struct cfs_hash_bd *bd) |
| { |
| /* NB: caller should hold hs->hs_rwlock if REHASH is set */ |
| if (likely(hs->hs_rehash_buckets == NULL)) { |
| cfs_hash_bd_from_key(hs, hs->hs_buckets, |
| hs->hs_cur_bits, key, bd); |
| } else { |
| LASSERT(hs->hs_rehash_bits != 0); |
| cfs_hash_bd_from_key(hs, hs->hs_rehash_buckets, |
| hs->hs_rehash_bits, key, bd); |
| } |
| } |
| EXPORT_SYMBOL(cfs_hash_bd_get); |
| |
| static inline void |
| cfs_hash_bd_dep_record(struct cfs_hash *hs, struct cfs_hash_bd *bd, int dep_cur) |
| { |
| if (likely(dep_cur <= bd->bd_bucket->hsb_depmax)) |
| return; |
| |
| bd->bd_bucket->hsb_depmax = dep_cur; |
| # if CFS_HASH_DEBUG_LEVEL >= CFS_HASH_DEBUG_1 |
| if (likely(warn_on_depth == 0 || |
| max(warn_on_depth, hs->hs_dep_max) >= dep_cur)) |
| return; |
| |
| spin_lock(&hs->hs_dep_lock); |
| hs->hs_dep_max = dep_cur; |
| hs->hs_dep_bkt = bd->bd_bucket->hsb_index; |
| hs->hs_dep_off = bd->bd_offset; |
| hs->hs_dep_bits = hs->hs_cur_bits; |
| spin_unlock(&hs->hs_dep_lock); |
| |
| cfs_wi_schedule(cfs_sched_rehash, &hs->hs_dep_wi); |
| # endif |
| } |
| |
| void |
| cfs_hash_bd_add_locked(struct cfs_hash *hs, struct cfs_hash_bd *bd, |
| struct hlist_node *hnode) |
| { |
| int rc; |
| |
| rc = hs->hs_hops->hop_hnode_add(hs, bd, hnode); |
| cfs_hash_bd_dep_record(hs, bd, rc); |
| bd->bd_bucket->hsb_version++; |
| if (unlikely(bd->bd_bucket->hsb_version == 0)) |
| bd->bd_bucket->hsb_version++; |
| bd->bd_bucket->hsb_count++; |
| |
| if (cfs_hash_with_counter(hs)) |
| atomic_inc(&hs->hs_count); |
| if (!cfs_hash_with_no_itemref(hs)) |
| cfs_hash_get(hs, hnode); |
| } |
| EXPORT_SYMBOL(cfs_hash_bd_add_locked); |
| |
| void |
| cfs_hash_bd_del_locked(struct cfs_hash *hs, struct cfs_hash_bd *bd, |
| struct hlist_node *hnode) |
| { |
| hs->hs_hops->hop_hnode_del(hs, bd, hnode); |
| |
| LASSERT(bd->bd_bucket->hsb_count > 0); |
| bd->bd_bucket->hsb_count--; |
| bd->bd_bucket->hsb_version++; |
| if (unlikely(bd->bd_bucket->hsb_version == 0)) |
| bd->bd_bucket->hsb_version++; |
| |
| if (cfs_hash_with_counter(hs)) { |
| LASSERT(atomic_read(&hs->hs_count) > 0); |
| atomic_dec(&hs->hs_count); |
| } |
| if (!cfs_hash_with_no_itemref(hs)) |
| cfs_hash_put_locked(hs, hnode); |
| } |
| EXPORT_SYMBOL(cfs_hash_bd_del_locked); |
| |
| void |
| cfs_hash_bd_move_locked(struct cfs_hash *hs, struct cfs_hash_bd *bd_old, |
| struct cfs_hash_bd *bd_new, struct hlist_node *hnode) |
| { |
| struct cfs_hash_bucket *obkt = bd_old->bd_bucket; |
| struct cfs_hash_bucket *nbkt = bd_new->bd_bucket; |
| int rc; |
| |
| if (cfs_hash_bd_compare(bd_old, bd_new) == 0) |
| return; |
| |
| /* use cfs_hash_bd_hnode_add/del, to avoid atomic & refcount ops |
| * in cfs_hash_bd_del/add_locked */ |
| hs->hs_hops->hop_hnode_del(hs, bd_old, hnode); |
| rc = hs->hs_hops->hop_hnode_add(hs, bd_new, hnode); |
| cfs_hash_bd_dep_record(hs, bd_new, rc); |
| |
| LASSERT(obkt->hsb_count > 0); |
| obkt->hsb_count--; |
| obkt->hsb_version++; |
| if (unlikely(obkt->hsb_version == 0)) |
| obkt->hsb_version++; |
| nbkt->hsb_count++; |
| nbkt->hsb_version++; |
| if (unlikely(nbkt->hsb_version == 0)) |
| nbkt->hsb_version++; |
| } |
| EXPORT_SYMBOL(cfs_hash_bd_move_locked); |
| |
| enum { |
| /** always set, for sanity (avoid ZERO intent) */ |
| CFS_HS_LOOKUP_MASK_FIND = 1 << 0, |
| /** return entry with a ref */ |
| CFS_HS_LOOKUP_MASK_REF = 1 << 1, |
| /** add entry if not existing */ |
| CFS_HS_LOOKUP_MASK_ADD = 1 << 2, |
| /** delete entry, ignore other masks */ |
| CFS_HS_LOOKUP_MASK_DEL = 1 << 3, |
| }; |
| |
| typedef enum cfs_hash_lookup_intent { |
| /** return item w/o refcount */ |
| CFS_HS_LOOKUP_IT_PEEK = CFS_HS_LOOKUP_MASK_FIND, |
| /** return item with refcount */ |
| CFS_HS_LOOKUP_IT_FIND = (CFS_HS_LOOKUP_MASK_FIND | |
| CFS_HS_LOOKUP_MASK_REF), |
| /** return item w/o refcount if existed, otherwise add */ |
| CFS_HS_LOOKUP_IT_ADD = (CFS_HS_LOOKUP_MASK_FIND | |
| CFS_HS_LOOKUP_MASK_ADD), |
| /** return item with refcount if existed, otherwise add */ |
| CFS_HS_LOOKUP_IT_FINDADD = (CFS_HS_LOOKUP_IT_FIND | |
| CFS_HS_LOOKUP_MASK_ADD), |
| /** delete if existed */ |
| CFS_HS_LOOKUP_IT_FINDDEL = (CFS_HS_LOOKUP_MASK_FIND | |
| CFS_HS_LOOKUP_MASK_DEL) |
| } cfs_hash_lookup_intent_t; |
| |
| static struct hlist_node * |
| cfs_hash_bd_lookup_intent(struct cfs_hash *hs, struct cfs_hash_bd *bd, |
| const void *key, struct hlist_node *hnode, |
| cfs_hash_lookup_intent_t intent) |
| |
| { |
| struct hlist_head *hhead = cfs_hash_bd_hhead(hs, bd); |
| struct hlist_node *ehnode; |
| struct hlist_node *match; |
| int intent_add = (intent & CFS_HS_LOOKUP_MASK_ADD) != 0; |
| |
| /* with this function, we can avoid a lot of useless refcount ops, |
| * which are expensive atomic operations most time. */ |
| match = intent_add ? NULL : hnode; |
| hlist_for_each(ehnode, hhead) { |
| if (!cfs_hash_keycmp(hs, key, ehnode)) |
| continue; |
| |
| if (match != NULL && match != ehnode) /* can't match */ |
| continue; |
| |
| /* match and ... */ |
| if ((intent & CFS_HS_LOOKUP_MASK_DEL) != 0) { |
| cfs_hash_bd_del_locked(hs, bd, ehnode); |
| return ehnode; |
| } |
| |
| /* caller wants refcount? */ |
| if ((intent & CFS_HS_LOOKUP_MASK_REF) != 0) |
| cfs_hash_get(hs, ehnode); |
| return ehnode; |
| } |
| /* no match item */ |
| if (!intent_add) |
| return NULL; |
| |
| LASSERT(hnode != NULL); |
| cfs_hash_bd_add_locked(hs, bd, hnode); |
| return hnode; |
| } |
| |
| struct hlist_node * |
| cfs_hash_bd_lookup_locked(struct cfs_hash *hs, struct cfs_hash_bd *bd, const void *key) |
| { |
| return cfs_hash_bd_lookup_intent(hs, bd, key, NULL, |
| CFS_HS_LOOKUP_IT_FIND); |
| } |
| EXPORT_SYMBOL(cfs_hash_bd_lookup_locked); |
| |
| struct hlist_node * |
| cfs_hash_bd_peek_locked(struct cfs_hash *hs, struct cfs_hash_bd *bd, const void *key) |
| { |
| return cfs_hash_bd_lookup_intent(hs, bd, key, NULL, |
| CFS_HS_LOOKUP_IT_PEEK); |
| } |
| EXPORT_SYMBOL(cfs_hash_bd_peek_locked); |
| |
| struct hlist_node * |
| cfs_hash_bd_findadd_locked(struct cfs_hash *hs, struct cfs_hash_bd *bd, |
| const void *key, struct hlist_node *hnode, |
| int noref) |
| { |
| return cfs_hash_bd_lookup_intent(hs, bd, key, hnode, |
| CFS_HS_LOOKUP_IT_ADD | |
| (!noref * CFS_HS_LOOKUP_MASK_REF)); |
| } |
| EXPORT_SYMBOL(cfs_hash_bd_findadd_locked); |
| |
| struct hlist_node * |
| cfs_hash_bd_finddel_locked(struct cfs_hash *hs, struct cfs_hash_bd *bd, |
| const void *key, struct hlist_node *hnode) |
| { |
| /* hnode can be NULL, we find the first item with @key */ |
| return cfs_hash_bd_lookup_intent(hs, bd, key, hnode, |
| CFS_HS_LOOKUP_IT_FINDDEL); |
| } |
| EXPORT_SYMBOL(cfs_hash_bd_finddel_locked); |
| |
| static void |
| cfs_hash_multi_bd_lock(struct cfs_hash *hs, struct cfs_hash_bd *bds, |
| unsigned n, int excl) |
| { |
| struct cfs_hash_bucket *prev = NULL; |
| int i; |
| |
| /** |
| * bds must be ascendantly ordered by bd->bd_bucket->hsb_index. |
| * NB: it's possible that several bds point to the same bucket but |
| * have different bd::bd_offset, so need take care of deadlock. |
| */ |
| cfs_hash_for_each_bd(bds, n, i) { |
| if (prev == bds[i].bd_bucket) |
| continue; |
| |
| LASSERT(prev == NULL || |
| prev->hsb_index < bds[i].bd_bucket->hsb_index); |
| cfs_hash_bd_lock(hs, &bds[i], excl); |
| prev = bds[i].bd_bucket; |
| } |
| } |
| |
| static void |
| cfs_hash_multi_bd_unlock(struct cfs_hash *hs, struct cfs_hash_bd *bds, |
| unsigned n, int excl) |
| { |
| struct cfs_hash_bucket *prev = NULL; |
| int i; |
| |
| cfs_hash_for_each_bd(bds, n, i) { |
| if (prev != bds[i].bd_bucket) { |
| cfs_hash_bd_unlock(hs, &bds[i], excl); |
| prev = bds[i].bd_bucket; |
| } |
| } |
| } |
| |
| static struct hlist_node * |
| cfs_hash_multi_bd_lookup_locked(struct cfs_hash *hs, struct cfs_hash_bd *bds, |
| unsigned n, const void *key) |
| { |
| struct hlist_node *ehnode; |
| unsigned i; |
| |
| cfs_hash_for_each_bd(bds, n, i) { |
| ehnode = cfs_hash_bd_lookup_intent(hs, &bds[i], key, NULL, |
| CFS_HS_LOOKUP_IT_FIND); |
| if (ehnode != NULL) |
| return ehnode; |
| } |
| return NULL; |
| } |
| |
| static struct hlist_node * |
| cfs_hash_multi_bd_findadd_locked(struct cfs_hash *hs, |
| struct cfs_hash_bd *bds, unsigned n, const void *key, |
| struct hlist_node *hnode, int noref) |
| { |
| struct hlist_node *ehnode; |
| int intent; |
| unsigned i; |
| |
| LASSERT(hnode != NULL); |
| intent = CFS_HS_LOOKUP_IT_PEEK | (!noref * CFS_HS_LOOKUP_MASK_REF); |
| |
| cfs_hash_for_each_bd(bds, n, i) { |
| ehnode = cfs_hash_bd_lookup_intent(hs, &bds[i], key, |
| NULL, intent); |
| if (ehnode != NULL) |
| return ehnode; |
| } |
| |
| if (i == 1) { /* only one bucket */ |
| cfs_hash_bd_add_locked(hs, &bds[0], hnode); |
| } else { |
| struct cfs_hash_bd mybd; |
| |
| cfs_hash_bd_get(hs, key, &mybd); |
| cfs_hash_bd_add_locked(hs, &mybd, hnode); |
| } |
| |
| return hnode; |
| } |
| |
| static struct hlist_node * |
| cfs_hash_multi_bd_finddel_locked(struct cfs_hash *hs, struct cfs_hash_bd *bds, |
| unsigned n, const void *key, |
| struct hlist_node *hnode) |
| { |
| struct hlist_node *ehnode; |
| unsigned i; |
| |
| cfs_hash_for_each_bd(bds, n, i) { |
| ehnode = cfs_hash_bd_lookup_intent(hs, &bds[i], key, hnode, |
| CFS_HS_LOOKUP_IT_FINDDEL); |
| if (ehnode != NULL) |
| return ehnode; |
| } |
| return NULL; |
| } |
| |
| static void |
| cfs_hash_bd_order(struct cfs_hash_bd *bd1, struct cfs_hash_bd *bd2) |
| { |
| int rc; |
| |
| if (bd2->bd_bucket == NULL) |
| return; |
| |
| if (bd1->bd_bucket == NULL) { |
| *bd1 = *bd2; |
| bd2->bd_bucket = NULL; |
| return; |
| } |
| |
| rc = cfs_hash_bd_compare(bd1, bd2); |
| if (rc == 0) { |
| bd2->bd_bucket = NULL; |
| |
| } else if (rc > 0) { /* swab bd1 and bd2 */ |
| struct cfs_hash_bd tmp; |
| |
| tmp = *bd2; |
| *bd2 = *bd1; |
| *bd1 = tmp; |
| } |
| } |
| |
| void |
| cfs_hash_dual_bd_get(struct cfs_hash *hs, const void *key, struct cfs_hash_bd *bds) |
| { |
| /* NB: caller should hold hs_lock.rw if REHASH is set */ |
| cfs_hash_bd_from_key(hs, hs->hs_buckets, |
| hs->hs_cur_bits, key, &bds[0]); |
| if (likely(hs->hs_rehash_buckets == NULL)) { |
| /* no rehash or not rehashing */ |
| bds[1].bd_bucket = NULL; |
| return; |
| } |
| |
| LASSERT(hs->hs_rehash_bits != 0); |
| cfs_hash_bd_from_key(hs, hs->hs_rehash_buckets, |
| hs->hs_rehash_bits, key, &bds[1]); |
| |
| cfs_hash_bd_order(&bds[0], &bds[1]); |
| } |
| EXPORT_SYMBOL(cfs_hash_dual_bd_get); |
| |
| void |
| cfs_hash_dual_bd_lock(struct cfs_hash *hs, struct cfs_hash_bd *bds, int excl) |
| { |
| cfs_hash_multi_bd_lock(hs, bds, 2, excl); |
| } |
| EXPORT_SYMBOL(cfs_hash_dual_bd_lock); |
| |
| void |
| cfs_hash_dual_bd_unlock(struct cfs_hash *hs, struct cfs_hash_bd *bds, int excl) |
| { |
| cfs_hash_multi_bd_unlock(hs, bds, 2, excl); |
| } |
| EXPORT_SYMBOL(cfs_hash_dual_bd_unlock); |
| |
| struct hlist_node * |
| cfs_hash_dual_bd_lookup_locked(struct cfs_hash *hs, struct cfs_hash_bd *bds, |
| const void *key) |
| { |
| return cfs_hash_multi_bd_lookup_locked(hs, bds, 2, key); |
| } |
| EXPORT_SYMBOL(cfs_hash_dual_bd_lookup_locked); |
| |
| struct hlist_node * |
| cfs_hash_dual_bd_findadd_locked(struct cfs_hash *hs, struct cfs_hash_bd *bds, |
| const void *key, struct hlist_node *hnode, |
| int noref) |
| { |
| return cfs_hash_multi_bd_findadd_locked(hs, bds, 2, key, |
| hnode, noref); |
| } |
| EXPORT_SYMBOL(cfs_hash_dual_bd_findadd_locked); |
| |
| struct hlist_node * |
| cfs_hash_dual_bd_finddel_locked(struct cfs_hash *hs, struct cfs_hash_bd *bds, |
| const void *key, struct hlist_node *hnode) |
| { |
| return cfs_hash_multi_bd_finddel_locked(hs, bds, 2, key, hnode); |
| } |
| EXPORT_SYMBOL(cfs_hash_dual_bd_finddel_locked); |
| |
| static void |
| cfs_hash_buckets_free(struct cfs_hash_bucket **buckets, |
| int bkt_size, int prev_size, int size) |
| { |
| int i; |
| |
| for (i = prev_size; i < size; i++) { |
| if (buckets[i] != NULL) |
| LIBCFS_FREE(buckets[i], bkt_size); |
| } |
| |
| LIBCFS_FREE(buckets, sizeof(buckets[0]) * size); |
| } |
| |
| /* |
| * Create or grow bucket memory. Return old_buckets if no allocation was |
| * needed, the newly allocated buckets if allocation was needed and |
| * successful, and NULL on error. |
| */ |
| static struct cfs_hash_bucket ** |
| cfs_hash_buckets_realloc(struct cfs_hash *hs, struct cfs_hash_bucket **old_bkts, |
| unsigned int old_size, unsigned int new_size) |
| { |
| struct cfs_hash_bucket **new_bkts; |
| int i; |
| |
| LASSERT(old_size == 0 || old_bkts != NULL); |
| |
| if (old_bkts != NULL && old_size == new_size) |
| return old_bkts; |
| |
| LIBCFS_ALLOC(new_bkts, sizeof(new_bkts[0]) * new_size); |
| if (new_bkts == NULL) |
| return NULL; |
| |
| if (old_bkts != NULL) { |
| memcpy(new_bkts, old_bkts, |
| min(old_size, new_size) * sizeof(*old_bkts)); |
| } |
| |
| for (i = old_size; i < new_size; i++) { |
| struct hlist_head *hhead; |
| struct cfs_hash_bd bd; |
| |
| LIBCFS_ALLOC(new_bkts[i], cfs_hash_bkt_size(hs)); |
| if (new_bkts[i] == NULL) { |
| cfs_hash_buckets_free(new_bkts, cfs_hash_bkt_size(hs), |
| old_size, new_size); |
| return NULL; |
| } |
| |
| new_bkts[i]->hsb_index = i; |
| new_bkts[i]->hsb_version = 1; /* shouldn't be zero */ |
| new_bkts[i]->hsb_depmax = -1; /* unknown */ |
| bd.bd_bucket = new_bkts[i]; |
| cfs_hash_bd_for_each_hlist(hs, &bd, hhead) |
| INIT_HLIST_HEAD(hhead); |
| |
| if (cfs_hash_with_no_lock(hs) || |
| cfs_hash_with_no_bktlock(hs)) |
| continue; |
| |
| if (cfs_hash_with_rw_bktlock(hs)) |
| rwlock_init(&new_bkts[i]->hsb_lock.rw); |
| else if (cfs_hash_with_spin_bktlock(hs)) |
| spin_lock_init(&new_bkts[i]->hsb_lock.spin); |
| else |
| LBUG(); /* invalid use-case */ |
| } |
| return new_bkts; |
| } |
| |
| /** |
| * Initialize new libcfs hash, where: |
| * @name - Descriptive hash name |
| * @cur_bits - Initial hash table size, in bits |
| * @max_bits - Maximum allowed hash table resize, in bits |
| * @ops - Registered hash table operations |
| * @flags - CFS_HASH_REHASH enable synamic hash resizing |
| * - CFS_HASH_SORT enable chained hash sort |
| */ |
| static int cfs_hash_rehash_worker(cfs_workitem_t *wi); |
| |
| #if CFS_HASH_DEBUG_LEVEL >= CFS_HASH_DEBUG_1 |
| static int cfs_hash_dep_print(cfs_workitem_t *wi) |
| { |
| struct cfs_hash *hs = container_of(wi, struct cfs_hash, hs_dep_wi); |
| int dep; |
| int bkt; |
| int off; |
| int bits; |
| |
| spin_lock(&hs->hs_dep_lock); |
| dep = hs->hs_dep_max; |
| bkt = hs->hs_dep_bkt; |
| off = hs->hs_dep_off; |
| bits = hs->hs_dep_bits; |
| spin_unlock(&hs->hs_dep_lock); |
| |
| LCONSOLE_WARN("#### HASH %s (bits: %d): max depth %d at bucket %d/%d\n", |
| hs->hs_name, bits, dep, bkt, off); |
| spin_lock(&hs->hs_dep_lock); |
| hs->hs_dep_bits = 0; /* mark as workitem done */ |
| spin_unlock(&hs->hs_dep_lock); |
| return 0; |
| } |
| |
| static void cfs_hash_depth_wi_init(struct cfs_hash *hs) |
| { |
| spin_lock_init(&hs->hs_dep_lock); |
| cfs_wi_init(&hs->hs_dep_wi, hs, cfs_hash_dep_print); |
| } |
| |
| static void cfs_hash_depth_wi_cancel(struct cfs_hash *hs) |
| { |
| if (cfs_wi_deschedule(cfs_sched_rehash, &hs->hs_dep_wi)) |
| return; |
| |
| spin_lock(&hs->hs_dep_lock); |
| while (hs->hs_dep_bits != 0) { |
| spin_unlock(&hs->hs_dep_lock); |
| cond_resched(); |
| spin_lock(&hs->hs_dep_lock); |
| } |
| spin_unlock(&hs->hs_dep_lock); |
| } |
| |
| #else /* CFS_HASH_DEBUG_LEVEL < CFS_HASH_DEBUG_1 */ |
| |
| static inline void cfs_hash_depth_wi_init(struct cfs_hash *hs) {} |
| static inline void cfs_hash_depth_wi_cancel(struct cfs_hash *hs) {} |
| |
| #endif /* CFS_HASH_DEBUG_LEVEL >= CFS_HASH_DEBUG_1 */ |
| |
| struct cfs_hash * |
| cfs_hash_create(char *name, unsigned cur_bits, unsigned max_bits, |
| unsigned bkt_bits, unsigned extra_bytes, |
| unsigned min_theta, unsigned max_theta, |
| cfs_hash_ops_t *ops, unsigned flags) |
| { |
| struct cfs_hash *hs; |
| int len; |
| |
| CLASSERT(CFS_HASH_THETA_BITS < 15); |
| |
| LASSERT(name != NULL); |
| LASSERT(ops != NULL); |
| LASSERT(ops->hs_key); |
| LASSERT(ops->hs_hash); |
| LASSERT(ops->hs_object); |
| LASSERT(ops->hs_keycmp); |
| LASSERT(ops->hs_get != NULL); |
| LASSERT(ops->hs_put_locked != NULL); |
| |
| if ((flags & CFS_HASH_REHASH) != 0) |
| flags |= CFS_HASH_COUNTER; /* must have counter */ |
| |
| LASSERT(cur_bits > 0); |
| LASSERT(cur_bits >= bkt_bits); |
| LASSERT(max_bits >= cur_bits && max_bits < 31); |
| LASSERT(ergo((flags & CFS_HASH_REHASH) == 0, cur_bits == max_bits)); |
| LASSERT(ergo((flags & CFS_HASH_REHASH) != 0, |
| (flags & CFS_HASH_NO_LOCK) == 0)); |
| LASSERT(ergo((flags & CFS_HASH_REHASH_KEY) != 0, |
| ops->hs_keycpy != NULL)); |
| |
| len = (flags & CFS_HASH_BIGNAME) == 0 ? |
| CFS_HASH_NAME_LEN : CFS_HASH_BIGNAME_LEN; |
| LIBCFS_ALLOC(hs, offsetof(struct cfs_hash, hs_name[len])); |
| if (hs == NULL) |
| return NULL; |
| |
| strncpy(hs->hs_name, name, len); |
| hs->hs_name[len - 1] = '\0'; |
| hs->hs_flags = flags; |
| |
| atomic_set(&hs->hs_refcount, 1); |
| atomic_set(&hs->hs_count, 0); |
| |
| cfs_hash_lock_setup(hs); |
| cfs_hash_hlist_setup(hs); |
| |
| hs->hs_cur_bits = (__u8)cur_bits; |
| hs->hs_min_bits = (__u8)cur_bits; |
| hs->hs_max_bits = (__u8)max_bits; |
| hs->hs_bkt_bits = (__u8)bkt_bits; |
| |
| hs->hs_ops = ops; |
| hs->hs_extra_bytes = extra_bytes; |
| hs->hs_rehash_bits = 0; |
| cfs_wi_init(&hs->hs_rehash_wi, hs, cfs_hash_rehash_worker); |
| cfs_hash_depth_wi_init(hs); |
| |
| if (cfs_hash_with_rehash(hs)) |
| __cfs_hash_set_theta(hs, min_theta, max_theta); |
| |
| hs->hs_buckets = cfs_hash_buckets_realloc(hs, NULL, 0, |
| CFS_HASH_NBKT(hs)); |
| if (hs->hs_buckets != NULL) |
| return hs; |
| |
| LIBCFS_FREE(hs, offsetof(struct cfs_hash, hs_name[len])); |
| return NULL; |
| } |
| EXPORT_SYMBOL(cfs_hash_create); |
| |
| /** |
| * Cleanup libcfs hash @hs. |
| */ |
| static void |
| cfs_hash_destroy(struct cfs_hash *hs) |
| { |
| struct hlist_node *hnode; |
| struct hlist_node *pos; |
| struct cfs_hash_bd bd; |
| int i; |
| |
| LASSERT(hs != NULL); |
| LASSERT(!cfs_hash_is_exiting(hs) && |
| !cfs_hash_is_iterating(hs)); |
| |
| /** |
| * prohibit further rehashes, don't need any lock because |
| * I'm the only (last) one can change it. |
| */ |
| hs->hs_exiting = 1; |
| if (cfs_hash_with_rehash(hs)) |
| cfs_hash_rehash_cancel(hs); |
| |
| cfs_hash_depth_wi_cancel(hs); |
| /* rehash should be done/canceled */ |
| LASSERT(hs->hs_buckets != NULL && |
| hs->hs_rehash_buckets == NULL); |
| |
| cfs_hash_for_each_bucket(hs, &bd, i) { |
| struct hlist_head *hhead; |
| |
| LASSERT(bd.bd_bucket != NULL); |
| /* no need to take this lock, just for consistent code */ |
| cfs_hash_bd_lock(hs, &bd, 1); |
| |
| cfs_hash_bd_for_each_hlist(hs, &bd, hhead) { |
| hlist_for_each_safe(hnode, pos, hhead) { |
| LASSERTF(!cfs_hash_with_assert_empty(hs), |
| "hash %s bucket %u(%u) is not " |
| " empty: %u items left\n", |
| hs->hs_name, bd.bd_bucket->hsb_index, |
| bd.bd_offset, bd.bd_bucket->hsb_count); |
| /* can't assert key valicate, because we |
| * can interrupt rehash */ |
| cfs_hash_bd_del_locked(hs, &bd, hnode); |
| cfs_hash_exit(hs, hnode); |
| } |
| } |
| LASSERT(bd.bd_bucket->hsb_count == 0); |
| cfs_hash_bd_unlock(hs, &bd, 1); |
| cond_resched(); |
| } |
| |
| LASSERT(atomic_read(&hs->hs_count) == 0); |
| |
| cfs_hash_buckets_free(hs->hs_buckets, cfs_hash_bkt_size(hs), |
| 0, CFS_HASH_NBKT(hs)); |
| i = cfs_hash_with_bigname(hs) ? |
| CFS_HASH_BIGNAME_LEN : CFS_HASH_NAME_LEN; |
| LIBCFS_FREE(hs, offsetof(struct cfs_hash, hs_name[i])); |
| } |
| |
| struct cfs_hash *cfs_hash_getref(struct cfs_hash *hs) |
| { |
| if (atomic_inc_not_zero(&hs->hs_refcount)) |
| return hs; |
| return NULL; |
| } |
| EXPORT_SYMBOL(cfs_hash_getref); |
| |
| void cfs_hash_putref(struct cfs_hash *hs) |
| { |
| if (atomic_dec_and_test(&hs->hs_refcount)) |
| cfs_hash_destroy(hs); |
| } |
| EXPORT_SYMBOL(cfs_hash_putref); |
| |
| static inline int |
| cfs_hash_rehash_bits(struct cfs_hash *hs) |
| { |
| if (cfs_hash_with_no_lock(hs) || |
| !cfs_hash_with_rehash(hs)) |
| return -EOPNOTSUPP; |
| |
| if (unlikely(cfs_hash_is_exiting(hs))) |
| return -ESRCH; |
| |
| if (unlikely(cfs_hash_is_rehashing(hs))) |
| return -EALREADY; |
| |
| if (unlikely(cfs_hash_is_iterating(hs))) |
| return -EAGAIN; |
| |
| /* XXX: need to handle case with max_theta != 2.0 |
| * and the case with min_theta != 0.5 */ |
| if ((hs->hs_cur_bits < hs->hs_max_bits) && |
| (__cfs_hash_theta(hs) > hs->hs_max_theta)) |
| return hs->hs_cur_bits + 1; |
| |
| if (!cfs_hash_with_shrink(hs)) |
| return 0; |
| |
| if ((hs->hs_cur_bits > hs->hs_min_bits) && |
| (__cfs_hash_theta(hs) < hs->hs_min_theta)) |
| return hs->hs_cur_bits - 1; |
| |
| return 0; |
| } |
| |
| /** |
| * don't allow inline rehash if: |
| * - user wants non-blocking change (add/del) on hash table |
| * - too many elements |
| */ |
| static inline int |
| cfs_hash_rehash_inline(struct cfs_hash *hs) |
| { |
| return !cfs_hash_with_nblk_change(hs) && |
| atomic_read(&hs->hs_count) < CFS_HASH_LOOP_HOG; |
| } |
| |
| /** |
| * Add item @hnode to libcfs hash @hs using @key. The registered |
| * ops->hs_get function will be called when the item is added. |
| */ |
| void |
| cfs_hash_add(struct cfs_hash *hs, const void *key, struct hlist_node *hnode) |
| { |
| struct cfs_hash_bd bd; |
| int bits; |
| |
| LASSERT(hlist_unhashed(hnode)); |
| |
| cfs_hash_lock(hs, 0); |
| cfs_hash_bd_get_and_lock(hs, key, &bd, 1); |
| |
| cfs_hash_key_validate(hs, key, hnode); |
| cfs_hash_bd_add_locked(hs, &bd, hnode); |
| |
| cfs_hash_bd_unlock(hs, &bd, 1); |
| |
| bits = cfs_hash_rehash_bits(hs); |
| cfs_hash_unlock(hs, 0); |
| if (bits > 0) |
| cfs_hash_rehash(hs, cfs_hash_rehash_inline(hs)); |
| } |
| EXPORT_SYMBOL(cfs_hash_add); |
| |
| static struct hlist_node * |
| cfs_hash_find_or_add(struct cfs_hash *hs, const void *key, |
| struct hlist_node *hnode, int noref) |
| { |
| struct hlist_node *ehnode; |
| struct cfs_hash_bd bds[2]; |
| int bits = 0; |
| |
| LASSERT(hlist_unhashed(hnode)); |
| |
| cfs_hash_lock(hs, 0); |
| cfs_hash_dual_bd_get_and_lock(hs, key, bds, 1); |
| |
| cfs_hash_key_validate(hs, key, hnode); |
| ehnode = cfs_hash_dual_bd_findadd_locked(hs, bds, key, |
| hnode, noref); |
| cfs_hash_dual_bd_unlock(hs, bds, 1); |
| |
| if (ehnode == hnode) /* new item added */ |
| bits = cfs_hash_rehash_bits(hs); |
| cfs_hash_unlock(hs, 0); |
| if (bits > 0) |
| cfs_hash_rehash(hs, cfs_hash_rehash_inline(hs)); |
| |
| return ehnode; |
| } |
| |
| /** |
| * Add item @hnode to libcfs hash @hs using @key. The registered |
| * ops->hs_get function will be called if the item was added. |
| * Returns 0 on success or -EALREADY on key collisions. |
| */ |
| int |
| cfs_hash_add_unique(struct cfs_hash *hs, const void *key, struct hlist_node *hnode) |
| { |
| return cfs_hash_find_or_add(hs, key, hnode, 1) != hnode ? |
| -EALREADY : 0; |
| } |
| EXPORT_SYMBOL(cfs_hash_add_unique); |
| |
| /** |
| * Add item @hnode to libcfs hash @hs using @key. If this @key |
| * already exists in the hash then ops->hs_get will be called on the |
| * conflicting entry and that entry will be returned to the caller. |
| * Otherwise ops->hs_get is called on the item which was added. |
| */ |
| void * |
| cfs_hash_findadd_unique(struct cfs_hash *hs, const void *key, |
| struct hlist_node *hnode) |
| { |
| hnode = cfs_hash_find_or_add(hs, key, hnode, 0); |
| |
| return cfs_hash_object(hs, hnode); |
| } |
| EXPORT_SYMBOL(cfs_hash_findadd_unique); |
| |
| /** |
| * Delete item @hnode from the libcfs hash @hs using @key. The @key |
| * is required to ensure the correct hash bucket is locked since there |
| * is no direct linkage from the item to the bucket. The object |
| * removed from the hash will be returned and obs->hs_put is called |
| * on the removed object. |
| */ |
| void * |
| cfs_hash_del(struct cfs_hash *hs, const void *key, struct hlist_node *hnode) |
| { |
| void *obj = NULL; |
| int bits = 0; |
| struct cfs_hash_bd bds[2]; |
| |
| cfs_hash_lock(hs, 0); |
| cfs_hash_dual_bd_get_and_lock(hs, key, bds, 1); |
| |
| /* NB: do nothing if @hnode is not in hash table */ |
| if (hnode == NULL || !hlist_unhashed(hnode)) { |
| if (bds[1].bd_bucket == NULL && hnode != NULL) { |
| cfs_hash_bd_del_locked(hs, &bds[0], hnode); |
| } else { |
| hnode = cfs_hash_dual_bd_finddel_locked(hs, bds, |
| key, hnode); |
| } |
| } |
| |
| if (hnode != NULL) { |
| obj = cfs_hash_object(hs, hnode); |
| bits = cfs_hash_rehash_bits(hs); |
| } |
| |
| cfs_hash_dual_bd_unlock(hs, bds, 1); |
| cfs_hash_unlock(hs, 0); |
| if (bits > 0) |
| cfs_hash_rehash(hs, cfs_hash_rehash_inline(hs)); |
| |
| return obj; |
| } |
| EXPORT_SYMBOL(cfs_hash_del); |
| |
| /** |
| * Delete item given @key in libcfs hash @hs. The first @key found in |
| * the hash will be removed, if the key exists multiple times in the hash |
| * @hs this function must be called once per key. The removed object |
| * will be returned and ops->hs_put is called on the removed object. |
| */ |
| void * |
| cfs_hash_del_key(struct cfs_hash *hs, const void *key) |
| { |
| return cfs_hash_del(hs, key, NULL); |
| } |
| EXPORT_SYMBOL(cfs_hash_del_key); |
| |
| /** |
| * Lookup an item using @key in the libcfs hash @hs and return it. |
| * If the @key is found in the hash hs->hs_get() is called and the |
| * matching objects is returned. It is the callers responsibility |
| * to call the counterpart ops->hs_put using the cfs_hash_put() macro |
| * when when finished with the object. If the @key was not found |
| * in the hash @hs NULL is returned. |
| */ |
| void * |
| cfs_hash_lookup(struct cfs_hash *hs, const void *key) |
| { |
| void *obj = NULL; |
| struct hlist_node *hnode; |
| struct cfs_hash_bd bds[2]; |
| |
| cfs_hash_lock(hs, 0); |
| cfs_hash_dual_bd_get_and_lock(hs, key, bds, 0); |
| |
| hnode = cfs_hash_dual_bd_lookup_locked(hs, bds, key); |
| if (hnode != NULL) |
| obj = cfs_hash_object(hs, hnode); |
| |
| cfs_hash_dual_bd_unlock(hs, bds, 0); |
| cfs_hash_unlock(hs, 0); |
| |
| return obj; |
| } |
| EXPORT_SYMBOL(cfs_hash_lookup); |
| |
| static void |
| cfs_hash_for_each_enter(struct cfs_hash *hs) |
| { |
| LASSERT(!cfs_hash_is_exiting(hs)); |
| |
| if (!cfs_hash_with_rehash(hs)) |
| return; |
| /* |
| * NB: it's race on cfs_has_t::hs_iterating, but doesn't matter |
| * because it's just an unreliable signal to rehash-thread, |
| * rehash-thread will try to finish rehash ASAP when seeing this. |
| */ |
| hs->hs_iterating = 1; |
| |
| cfs_hash_lock(hs, 1); |
| hs->hs_iterators++; |
| |
| /* NB: iteration is mostly called by service thread, |
| * we tend to cancel pending rehash-request, instead of |
| * blocking service thread, we will relaunch rehash request |
| * after iteration */ |
| if (cfs_hash_is_rehashing(hs)) |
| cfs_hash_rehash_cancel_locked(hs); |
| cfs_hash_unlock(hs, 1); |
| } |
| |
| static void |
| cfs_hash_for_each_exit(struct cfs_hash *hs) |
| { |
| int remained; |
| int bits; |
| |
| if (!cfs_hash_with_rehash(hs)) |
| return; |
| cfs_hash_lock(hs, 1); |
| remained = --hs->hs_iterators; |
| bits = cfs_hash_rehash_bits(hs); |
| cfs_hash_unlock(hs, 1); |
| /* NB: it's race on cfs_has_t::hs_iterating, see above */ |
| if (remained == 0) |
| hs->hs_iterating = 0; |
| if (bits > 0) { |
| cfs_hash_rehash(hs, atomic_read(&hs->hs_count) < |
| CFS_HASH_LOOP_HOG); |
| } |
| } |
| |
| /** |
| * For each item in the libcfs hash @hs call the passed callback @func |
| * and pass to it as an argument each hash item and the private @data. |
| * |
| * a) the function may sleep! |
| * b) during the callback: |
| * . the bucket lock is held so the callback must never sleep. |
| * . if @removal_safe is true, use can remove current item by |
| * cfs_hash_bd_del_locked |
| */ |
| static __u64 |
| cfs_hash_for_each_tight(struct cfs_hash *hs, cfs_hash_for_each_cb_t func, |
| void *data, int remove_safe) |
| { |
| struct hlist_node *hnode; |
| struct hlist_node *pos; |
| struct cfs_hash_bd bd; |
| __u64 count = 0; |
| int excl = !!remove_safe; |
| int loop = 0; |
| int i; |
| |
| cfs_hash_for_each_enter(hs); |
| |
| cfs_hash_lock(hs, 0); |
| LASSERT(!cfs_hash_is_rehashing(hs)); |
| |
| cfs_hash_for_each_bucket(hs, &bd, i) { |
| struct hlist_head *hhead; |
| |
| cfs_hash_bd_lock(hs, &bd, excl); |
| if (func == NULL) { /* only glimpse size */ |
| count += bd.bd_bucket->hsb_count; |
| cfs_hash_bd_unlock(hs, &bd, excl); |
| continue; |
| } |
| |
| cfs_hash_bd_for_each_hlist(hs, &bd, hhead) { |
| hlist_for_each_safe(hnode, pos, hhead) { |
| cfs_hash_bucket_validate(hs, &bd, hnode); |
| count++; |
| loop++; |
| if (func(hs, &bd, hnode, data)) { |
| cfs_hash_bd_unlock(hs, &bd, excl); |
| goto out; |
| } |
| } |
| } |
| cfs_hash_bd_unlock(hs, &bd, excl); |
| if (loop < CFS_HASH_LOOP_HOG) |
| continue; |
| loop = 0; |
| cfs_hash_unlock(hs, 0); |
| cond_resched(); |
| cfs_hash_lock(hs, 0); |
| } |
| out: |
| cfs_hash_unlock(hs, 0); |
| |
| cfs_hash_for_each_exit(hs); |
| return count; |
| } |
| |
| typedef struct { |
| cfs_hash_cond_opt_cb_t func; |
| void *arg; |
| } cfs_hash_cond_arg_t; |
| |
| static int |
| cfs_hash_cond_del_locked(struct cfs_hash *hs, struct cfs_hash_bd *bd, |
| struct hlist_node *hnode, void *data) |
| { |
| cfs_hash_cond_arg_t *cond = data; |
| |
| if (cond->func(cfs_hash_object(hs, hnode), cond->arg)) |
| cfs_hash_bd_del_locked(hs, bd, hnode); |
| return 0; |
| } |
| |
| /** |
| * Delete item from the libcfs hash @hs when @func return true. |
| * The write lock being hold during loop for each bucket to avoid |
| * any object be reference. |
| */ |
| void |
| cfs_hash_cond_del(struct cfs_hash *hs, cfs_hash_cond_opt_cb_t func, void *data) |
| { |
| cfs_hash_cond_arg_t arg = { |
| .func = func, |
| .arg = data, |
| }; |
| |
| cfs_hash_for_each_tight(hs, cfs_hash_cond_del_locked, &arg, 1); |
| } |
| EXPORT_SYMBOL(cfs_hash_cond_del); |
| |
| void |
| cfs_hash_for_each(struct cfs_hash *hs, |
| cfs_hash_for_each_cb_t func, void *data) |
| { |
| cfs_hash_for_each_tight(hs, func, data, 0); |
| } |
| EXPORT_SYMBOL(cfs_hash_for_each); |
| |
| void |
| cfs_hash_for_each_safe(struct cfs_hash *hs, |
| cfs_hash_for_each_cb_t func, void *data) |
| { |
| cfs_hash_for_each_tight(hs, func, data, 1); |
| } |
| EXPORT_SYMBOL(cfs_hash_for_each_safe); |
| |
| static int |
| cfs_hash_peek(struct cfs_hash *hs, struct cfs_hash_bd *bd, |
| struct hlist_node *hnode, void *data) |
| { |
| *(int *)data = 0; |
| return 1; /* return 1 to break the loop */ |
| } |
| |
| int |
| cfs_hash_is_empty(struct cfs_hash *hs) |
| { |
| int empty = 1; |
| |
| cfs_hash_for_each_tight(hs, cfs_hash_peek, &empty, 0); |
| return empty; |
| } |
| EXPORT_SYMBOL(cfs_hash_is_empty); |
| |
| __u64 |
| cfs_hash_size_get(struct cfs_hash *hs) |
| { |
| return cfs_hash_with_counter(hs) ? |
| atomic_read(&hs->hs_count) : |
| cfs_hash_for_each_tight(hs, NULL, NULL, 0); |
| } |
| EXPORT_SYMBOL(cfs_hash_size_get); |
| |
| /* |
| * cfs_hash_for_each_relax: |
| * Iterate the hash table and call @func on each item without |
| * any lock. This function can't guarantee to finish iteration |
| * if these features are enabled: |
| * |
| * a. if rehash_key is enabled, an item can be moved from |
| * one bucket to another bucket |
| * b. user can remove non-zero-ref item from hash-table, |
| * so the item can be removed from hash-table, even worse, |
| * it's possible that user changed key and insert to another |
| * hash bucket. |
| * there's no way for us to finish iteration correctly on previous |
| * two cases, so iteration has to be stopped on change. |
| */ |
| static int |
| cfs_hash_for_each_relax(struct cfs_hash *hs, cfs_hash_for_each_cb_t func, void *data) |
| { |
| struct hlist_node *hnode; |
| struct hlist_node *tmp; |
| struct cfs_hash_bd bd; |
| __u32 version; |
| int count = 0; |
| int stop_on_change; |
| int rc; |
| int i; |
| |
| stop_on_change = cfs_hash_with_rehash_key(hs) || |
| !cfs_hash_with_no_itemref(hs) || |
| CFS_HOP(hs, put_locked) == NULL; |
| cfs_hash_lock(hs, 0); |
| LASSERT(!cfs_hash_is_rehashing(hs)); |
| |
| cfs_hash_for_each_bucket(hs, &bd, i) { |
| struct hlist_head *hhead; |
| |
| cfs_hash_bd_lock(hs, &bd, 0); |
| version = cfs_hash_bd_version_get(&bd); |
| |
| cfs_hash_bd_for_each_hlist(hs, &bd, hhead) { |
| for (hnode = hhead->first; hnode != NULL;) { |
| cfs_hash_bucket_validate(hs, &bd, hnode); |
| cfs_hash_get(hs, hnode); |
| cfs_hash_bd_unlock(hs, &bd, 0); |
| cfs_hash_unlock(hs, 0); |
| |
| rc = func(hs, &bd, hnode, data); |
| if (stop_on_change) |
| cfs_hash_put(hs, hnode); |
| cond_resched(); |
| count++; |
| |
| cfs_hash_lock(hs, 0); |
| cfs_hash_bd_lock(hs, &bd, 0); |
| if (!stop_on_change) { |
| tmp = hnode->next; |
| cfs_hash_put_locked(hs, hnode); |
| hnode = tmp; |
| } else { /* bucket changed? */ |
| if (version != |
| cfs_hash_bd_version_get(&bd)) |
| break; |
| /* safe to continue because no change */ |
| hnode = hnode->next; |
| } |
| if (rc) /* callback wants to break iteration */ |
| break; |
| } |
| } |
| cfs_hash_bd_unlock(hs, &bd, 0); |
| } |
| cfs_hash_unlock(hs, 0); |
| |
| return count; |
| } |
| |
| int |
| cfs_hash_for_each_nolock(struct cfs_hash *hs, |
| cfs_hash_for_each_cb_t func, void *data) |
| { |
| if (cfs_hash_with_no_lock(hs) || |
| cfs_hash_with_rehash_key(hs) || |
| !cfs_hash_with_no_itemref(hs)) |
| return -EOPNOTSUPP; |
| |
| if (CFS_HOP(hs, get) == NULL || |
| (CFS_HOP(hs, put) == NULL && |
| CFS_HOP(hs, put_locked) == NULL)) |
| return -EOPNOTSUPP; |
| |
| cfs_hash_for_each_enter(hs); |
| cfs_hash_for_each_relax(hs, func, data); |
| cfs_hash_for_each_exit(hs); |
| |
| return 0; |
| } |
| EXPORT_SYMBOL(cfs_hash_for_each_nolock); |
| |
| /** |
| * For each hash bucket in the libcfs hash @hs call the passed callback |
| * @func until all the hash buckets are empty. The passed callback @func |
| * or the previously registered callback hs->hs_put must remove the item |
| * from the hash. You may either use the cfs_hash_del() or hlist_del() |
| * functions. No rwlocks will be held during the callback @func it is |
| * safe to sleep if needed. This function will not terminate until the |
| * hash is empty. Note it is still possible to concurrently add new |
| * items in to the hash. It is the callers responsibility to ensure |
| * the required locking is in place to prevent concurrent insertions. |
| */ |
| int |
| cfs_hash_for_each_empty(struct cfs_hash *hs, |
| cfs_hash_for_each_cb_t func, void *data) |
| { |
| unsigned i = 0; |
| |
| if (cfs_hash_with_no_lock(hs)) |
| return -EOPNOTSUPP; |
| |
| if (CFS_HOP(hs, get) == NULL || |
| (CFS_HOP(hs, put) == NULL && |
| CFS_HOP(hs, put_locked) == NULL)) |
| return -EOPNOTSUPP; |
| |
| cfs_hash_for_each_enter(hs); |
| while (cfs_hash_for_each_relax(hs, func, data)) { |
| CDEBUG(D_INFO, "Try to empty hash: %s, loop: %u\n", |
| hs->hs_name, i++); |
| } |
| cfs_hash_for_each_exit(hs); |
| return 0; |
| } |
| EXPORT_SYMBOL(cfs_hash_for_each_empty); |
| |
| void |
| cfs_hash_hlist_for_each(struct cfs_hash *hs, unsigned hindex, |
| cfs_hash_for_each_cb_t func, void *data) |
| { |
| struct hlist_head *hhead; |
| struct hlist_node *hnode; |
| struct cfs_hash_bd bd; |
| |
| cfs_hash_for_each_enter(hs); |
| cfs_hash_lock(hs, 0); |
| if (hindex >= CFS_HASH_NHLIST(hs)) |
| goto out; |
| |
| cfs_hash_bd_index_set(hs, hindex, &bd); |
| |
| cfs_hash_bd_lock(hs, &bd, 0); |
| hhead = cfs_hash_bd_hhead(hs, &bd); |
| hlist_for_each(hnode, hhead) { |
| if (func(hs, &bd, hnode, data)) |
| break; |
| } |
| cfs_hash_bd_unlock(hs, &bd, 0); |
| out: |
| cfs_hash_unlock(hs, 0); |
| cfs_hash_for_each_exit(hs); |
| } |
| |
| EXPORT_SYMBOL(cfs_hash_hlist_for_each); |
| |
| /* |
| * For each item in the libcfs hash @hs which matches the @key call |
| * the passed callback @func and pass to it as an argument each hash |
| * item and the private @data. During the callback the bucket lock |
| * is held so the callback must never sleep. |
| */ |
| void |
| cfs_hash_for_each_key(struct cfs_hash *hs, const void *key, |
| cfs_hash_for_each_cb_t func, void *data) |
| { |
| struct hlist_node *hnode; |
| struct cfs_hash_bd bds[2]; |
| unsigned i; |
| |
| cfs_hash_lock(hs, 0); |
| |
| cfs_hash_dual_bd_get_and_lock(hs, key, bds, 0); |
| |
| cfs_hash_for_each_bd(bds, 2, i) { |
| struct hlist_head *hlist = cfs_hash_bd_hhead(hs, &bds[i]); |
| |
| hlist_for_each(hnode, hlist) { |
| cfs_hash_bucket_validate(hs, &bds[i], hnode); |
| |
| if (cfs_hash_keycmp(hs, key, hnode)) { |
| if (func(hs, &bds[i], hnode, data)) |
| break; |
| } |
| } |
| } |
| |
| cfs_hash_dual_bd_unlock(hs, bds, 0); |
| cfs_hash_unlock(hs, 0); |
| } |
| EXPORT_SYMBOL(cfs_hash_for_each_key); |
| |
| /** |
| * Rehash the libcfs hash @hs to the given @bits. This can be used |
| * to grow the hash size when excessive chaining is detected, or to |
| * shrink the hash when it is larger than needed. When the CFS_HASH_REHASH |
| * flag is set in @hs the libcfs hash may be dynamically rehashed |
| * during addition or removal if the hash's theta value exceeds |
| * either the hs->hs_min_theta or hs->max_theta values. By default |
| * these values are tuned to keep the chained hash depth small, and |
| * this approach assumes a reasonably uniform hashing function. The |
| * theta thresholds for @hs are tunable via cfs_hash_set_theta(). |
| */ |
| void |
| cfs_hash_rehash_cancel_locked(struct cfs_hash *hs) |
| { |
| int i; |
| |
| /* need hold cfs_hash_lock(hs, 1) */ |
| LASSERT(cfs_hash_with_rehash(hs) && |
| !cfs_hash_with_no_lock(hs)); |
| |
| if (!cfs_hash_is_rehashing(hs)) |
| return; |
| |
| if (cfs_wi_deschedule(cfs_sched_rehash, &hs->hs_rehash_wi)) { |
| hs->hs_rehash_bits = 0; |
| return; |
| } |
| |
| for (i = 2; cfs_hash_is_rehashing(hs); i++) { |
| cfs_hash_unlock(hs, 1); |
| /* raise console warning while waiting too long */ |
| CDEBUG(IS_PO2(i >> 3) ? D_WARNING : D_INFO, |
| "hash %s is still rehashing, rescheded %d\n", |
| hs->hs_name, i - 1); |
| cond_resched(); |
| cfs_hash_lock(hs, 1); |
| } |
| } |
| EXPORT_SYMBOL(cfs_hash_rehash_cancel_locked); |
| |
| void |
| cfs_hash_rehash_cancel(struct cfs_hash *hs) |
| { |
| cfs_hash_lock(hs, 1); |
| cfs_hash_rehash_cancel_locked(hs); |
| cfs_hash_unlock(hs, 1); |
| } |
| EXPORT_SYMBOL(cfs_hash_rehash_cancel); |
| |
| int |
| cfs_hash_rehash(struct cfs_hash *hs, int do_rehash) |
| { |
| int rc; |
| |
| LASSERT(cfs_hash_with_rehash(hs) && !cfs_hash_with_no_lock(hs)); |
| |
| cfs_hash_lock(hs, 1); |
| |
| rc = cfs_hash_rehash_bits(hs); |
| if (rc <= 0) { |
| cfs_hash_unlock(hs, 1); |
| return rc; |
| } |
| |
| hs->hs_rehash_bits = rc; |
| if (!do_rehash) { |
| /* launch and return */ |
| cfs_wi_schedule(cfs_sched_rehash, &hs->hs_rehash_wi); |
| cfs_hash_unlock(hs, 1); |
| return 0; |
| } |
| |
| /* rehash right now */ |
| cfs_hash_unlock(hs, 1); |
| |
| return cfs_hash_rehash_worker(&hs->hs_rehash_wi); |
| } |
| EXPORT_SYMBOL(cfs_hash_rehash); |
| |
| static int |
| cfs_hash_rehash_bd(struct cfs_hash *hs, struct cfs_hash_bd *old) |
| { |
| struct cfs_hash_bd new; |
| struct hlist_head *hhead; |
| struct hlist_node *hnode; |
| struct hlist_node *pos; |
| void *key; |
| int c = 0; |
| |
| /* hold cfs_hash_lock(hs, 1), so don't need any bucket lock */ |
| cfs_hash_bd_for_each_hlist(hs, old, hhead) { |
| hlist_for_each_safe(hnode, pos, hhead) { |
| key = cfs_hash_key(hs, hnode); |
| LASSERT(key != NULL); |
| /* Validate hnode is in the correct bucket. */ |
| cfs_hash_bucket_validate(hs, old, hnode); |
| /* |
| * Delete from old hash bucket; move to new bucket. |
| * ops->hs_key must be defined. |
| */ |
| cfs_hash_bd_from_key(hs, hs->hs_rehash_buckets, |
| hs->hs_rehash_bits, key, &new); |
| cfs_hash_bd_move_locked(hs, old, &new, hnode); |
| c++; |
| } |
| } |
| |
| return c; |
| } |
| |
| static int |
| cfs_hash_rehash_worker(cfs_workitem_t *wi) |
| { |
| struct cfs_hash *hs = container_of(wi, struct cfs_hash, hs_rehash_wi); |
| struct cfs_hash_bucket **bkts; |
| struct cfs_hash_bd bd; |
| unsigned int old_size; |
| unsigned int new_size; |
| int bsize; |
| int count = 0; |
| int rc = 0; |
| int i; |
| |
| LASSERT (hs != NULL && cfs_hash_with_rehash(hs)); |
| |
| cfs_hash_lock(hs, 0); |
| LASSERT(cfs_hash_is_rehashing(hs)); |
| |
| old_size = CFS_HASH_NBKT(hs); |
| new_size = CFS_HASH_RH_NBKT(hs); |
| |
| cfs_hash_unlock(hs, 0); |
| |
| /* |
| * don't need hs::hs_rwlock for hs::hs_buckets, |
| * because nobody can change bkt-table except me. |
| */ |
| bkts = cfs_hash_buckets_realloc(hs, hs->hs_buckets, |
| old_size, new_size); |
| cfs_hash_lock(hs, 1); |
| if (bkts == NULL) { |
| rc = -ENOMEM; |
| goto out; |
| } |
| |
| if (bkts == hs->hs_buckets) { |
| bkts = NULL; /* do nothing */ |
| goto out; |
| } |
| |
| rc = __cfs_hash_theta(hs); |
| if ((rc >= hs->hs_min_theta) && (rc <= hs->hs_max_theta)) { |
| /* free the new allocated bkt-table */ |
| old_size = new_size; |
| new_size = CFS_HASH_NBKT(hs); |
| rc = -EALREADY; |
| goto out; |
| } |
| |
| LASSERT(hs->hs_rehash_buckets == NULL); |
| hs->hs_rehash_buckets = bkts; |
| |
| rc = 0; |
| cfs_hash_for_each_bucket(hs, &bd, i) { |
| if (cfs_hash_is_exiting(hs)) { |
| rc = -ESRCH; |
| /* someone wants to destroy the hash, abort now */ |
| if (old_size < new_size) /* OK to free old bkt-table */ |
| break; |
| /* it's shrinking, need free new bkt-table */ |
| hs->hs_rehash_buckets = NULL; |
| old_size = new_size; |
| new_size = CFS_HASH_NBKT(hs); |
| goto out; |
| } |
| |
| count += cfs_hash_rehash_bd(hs, &bd); |
| if (count < CFS_HASH_LOOP_HOG || |
| cfs_hash_is_iterating(hs)) { /* need to finish ASAP */ |
| continue; |
| } |
| |
| count = 0; |
| cfs_hash_unlock(hs, 1); |
| cond_resched(); |
| cfs_hash_lock(hs, 1); |
| } |
| |
| hs->hs_rehash_count++; |
| |
| bkts = hs->hs_buckets; |
| hs->hs_buckets = hs->hs_rehash_buckets; |
| hs->hs_rehash_buckets = NULL; |
| |
| hs->hs_cur_bits = hs->hs_rehash_bits; |
| out: |
| hs->hs_rehash_bits = 0; |
| if (rc == -ESRCH) /* never be scheduled again */ |
| cfs_wi_exit(cfs_sched_rehash, wi); |
| bsize = cfs_hash_bkt_size(hs); |
| cfs_hash_unlock(hs, 1); |
| /* can't refer to @hs anymore because it could be destroyed */ |
| if (bkts != NULL) |
| cfs_hash_buckets_free(bkts, bsize, new_size, old_size); |
| if (rc != 0) |
| CDEBUG(D_INFO, "early quit of rehashing: %d\n", rc); |
| /* return 1 only if cfs_wi_exit is called */ |
| return rc == -ESRCH; |
| } |
| |
| /** |
| * Rehash the object referenced by @hnode in the libcfs hash @hs. The |
| * @old_key must be provided to locate the objects previous location |
| * in the hash, and the @new_key will be used to reinsert the object. |
| * Use this function instead of a cfs_hash_add() + cfs_hash_del() |
| * combo when it is critical that there is no window in time where the |
| * object is missing from the hash. When an object is being rehashed |
| * the registered cfs_hash_get() and cfs_hash_put() functions will |
| * not be called. |
| */ |
| void cfs_hash_rehash_key(struct cfs_hash *hs, const void *old_key, |
| void *new_key, struct hlist_node *hnode) |
| { |
| struct cfs_hash_bd bds[3]; |
| struct cfs_hash_bd old_bds[2]; |
| struct cfs_hash_bd new_bd; |
| |
| LASSERT(!hlist_unhashed(hnode)); |
| |
| cfs_hash_lock(hs, 0); |
| |
| cfs_hash_dual_bd_get(hs, old_key, old_bds); |
| cfs_hash_bd_get(hs, new_key, &new_bd); |
| |
| bds[0] = old_bds[0]; |
| bds[1] = old_bds[1]; |
| bds[2] = new_bd; |
| |
| /* NB: bds[0] and bds[1] are ordered already */ |
| cfs_hash_bd_order(&bds[1], &bds[2]); |
| cfs_hash_bd_order(&bds[0], &bds[1]); |
| |
| cfs_hash_multi_bd_lock(hs, bds, 3, 1); |
| if (likely(old_bds[1].bd_bucket == NULL)) { |
| cfs_hash_bd_move_locked(hs, &old_bds[0], &new_bd, hnode); |
| } else { |
| cfs_hash_dual_bd_finddel_locked(hs, old_bds, old_key, hnode); |
| cfs_hash_bd_add_locked(hs, &new_bd, hnode); |
| } |
| /* overwrite key inside locks, otherwise may screw up with |
| * other operations, i.e: rehash */ |
| cfs_hash_keycpy(hs, new_key, hnode); |
| |
| cfs_hash_multi_bd_unlock(hs, bds, 3, 1); |
| cfs_hash_unlock(hs, 0); |
| } |
| EXPORT_SYMBOL(cfs_hash_rehash_key); |
| |
| int cfs_hash_debug_header(struct seq_file *m) |
| { |
| return seq_printf(m, "%-*s%6s%6s%6s%6s%6s%6s%6s%7s%8s%8s%8s%s\n", |
| CFS_HASH_BIGNAME_LEN, |
| "name", "cur", "min", "max", "theta", "t-min", "t-max", |
| "flags", "rehash", "count", "maxdep", "maxdepb", |
| " distribution"); |
| } |
| EXPORT_SYMBOL(cfs_hash_debug_header); |
| |
| static struct cfs_hash_bucket ** |
| cfs_hash_full_bkts(struct cfs_hash *hs) |
| { |
| /* NB: caller should hold hs->hs_rwlock if REHASH is set */ |
| if (hs->hs_rehash_buckets == NULL) |
| return hs->hs_buckets; |
| |
| LASSERT(hs->hs_rehash_bits != 0); |
| return hs->hs_rehash_bits > hs->hs_cur_bits ? |
| hs->hs_rehash_buckets : hs->hs_buckets; |
| } |
| |
| static unsigned int |
| cfs_hash_full_nbkt(struct cfs_hash *hs) |
| { |
| /* NB: caller should hold hs->hs_rwlock if REHASH is set */ |
| if (hs->hs_rehash_buckets == NULL) |
| return CFS_HASH_NBKT(hs); |
| |
| LASSERT(hs->hs_rehash_bits != 0); |
| return hs->hs_rehash_bits > hs->hs_cur_bits ? |
| CFS_HASH_RH_NBKT(hs) : CFS_HASH_NBKT(hs); |
| } |
| |
| int cfs_hash_debug_str(struct cfs_hash *hs, struct seq_file *m) |
| { |
| int dist[8] = { 0, }; |
| int maxdep = -1; |
| int maxdepb = -1; |
| int total = 0; |
| int theta; |
| int i; |
| |
| cfs_hash_lock(hs, 0); |
| theta = __cfs_hash_theta(hs); |
| |
| seq_printf(m, "%-*s %5d %5d %5d %d.%03d %d.%03d %d.%03d 0x%02x %6d ", |
| CFS_HASH_BIGNAME_LEN, hs->hs_name, |
| 1 << hs->hs_cur_bits, 1 << hs->hs_min_bits, |
| 1 << hs->hs_max_bits, |
| __cfs_hash_theta_int(theta), __cfs_hash_theta_frac(theta), |
| __cfs_hash_theta_int(hs->hs_min_theta), |
| __cfs_hash_theta_frac(hs->hs_min_theta), |
| __cfs_hash_theta_int(hs->hs_max_theta), |
| __cfs_hash_theta_frac(hs->hs_max_theta), |
| hs->hs_flags, hs->hs_rehash_count); |
| |
| /* |
| * The distribution is a summary of the chained hash depth in |
| * each of the libcfs hash buckets. Each buckets hsb_count is |
| * divided by the hash theta value and used to generate a |
| * histogram of the hash distribution. A uniform hash will |
| * result in all hash buckets being close to the average thus |
| * only the first few entries in the histogram will be non-zero. |
| * If you hash function results in a non-uniform hash the will |
| * be observable by outlier bucks in the distribution histogram. |
| * |
| * Uniform hash distribution: 128/128/0/0/0/0/0/0 |
| * Non-Uniform hash distribution: 128/125/0/0/0/0/2/1 |
| */ |
| for (i = 0; i < cfs_hash_full_nbkt(hs); i++) { |
| struct cfs_hash_bd bd; |
| |
| bd.bd_bucket = cfs_hash_full_bkts(hs)[i]; |
| cfs_hash_bd_lock(hs, &bd, 0); |
| if (maxdep < bd.bd_bucket->hsb_depmax) { |
| maxdep = bd.bd_bucket->hsb_depmax; |
| maxdepb = ffz(~maxdep); |
| } |
| total += bd.bd_bucket->hsb_count; |
| dist[min(__cfs_fls(bd.bd_bucket->hsb_count/max(theta,1)),7)]++; |
| cfs_hash_bd_unlock(hs, &bd, 0); |
| } |
| |
| seq_printf(m, "%7d %7d %7d ", total, maxdep, maxdepb); |
| for (i = 0; i < 8; i++) |
| seq_printf(m, "%d%c", dist[i], (i == 7) ? '\n' : '/'); |
| |
| cfs_hash_unlock(hs, 0); |
| |
| return 0; |
| } |
| EXPORT_SYMBOL(cfs_hash_debug_str); |