2086 lines
54 KiB
C
2086 lines
54 KiB
C
/*
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* GPL HEADER START
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*
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 only,
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* as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License version 2 for more details (a copy is included
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* in the LICENSE file that accompanied this code).
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*
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* You should have received a copy of the GNU General Public License
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* version 2 along with this program; If not, see
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* http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
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*
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* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
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* CA 95054 USA or visit www.sun.com if you need additional information or
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* have any questions.
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*
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* GPL HEADER END
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*/
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/*
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* Copyright (c) 2009, 2010, Oracle and/or its affiliates. All rights reserved.
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* Use is subject to license terms.
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*
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* Copyright (c) 2011, 2012, Intel Corporation.
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*/
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/*
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* This file is part of Lustre, http://www.lustre.org/
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* Lustre is a trademark of Sun Microsystems, Inc.
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*
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* libcfs/libcfs/hash.c
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*
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* Implement a hash class for hash process in lustre system.
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*
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* Author: YuZhangyong <yzy@clusterfs.com>
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*
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* 2008-08-15: Brian Behlendorf <behlendorf1@llnl.gov>
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* - Simplified API and improved documentation
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* - Added per-hash feature flags:
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* * CFS_HASH_DEBUG additional validation
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* * CFS_HASH_REHASH dynamic rehashing
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* - Added per-hash statistics
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* - General performance enhancements
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*
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* 2009-07-31: Liang Zhen <zhen.liang@sun.com>
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* - move all stuff to libcfs
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* - don't allow cur_bits != max_bits without setting of CFS_HASH_REHASH
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* - ignore hs_rwlock if without CFS_HASH_REHASH setting
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* - buckets are allocated one by one(instead of contiguous memory),
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* to avoid unnecessary cacheline conflict
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*
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* 2010-03-01: Liang Zhen <zhen.liang@sun.com>
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* - "bucket" is a group of hlist_head now, user can specify bucket size
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* by bkt_bits of cfs_hash_create(), all hlist_heads in a bucket share
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* one lock for reducing memory overhead.
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*
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* - support lockless hash, caller will take care of locks:
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* avoid lock overhead for hash tables that are already protected
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* by locking in the caller for another reason
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*
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* - support both spin_lock/rwlock for bucket:
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* overhead of spinlock contention is lower than read/write
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* contention of rwlock, so using spinlock to serialize operations on
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* bucket is more reasonable for those frequently changed hash tables
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*
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* - support one-single lock mode:
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* one lock to protect all hash operations to avoid overhead of
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* multiple locks if hash table is always small
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*
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* - removed a lot of unnecessary addref & decref on hash element:
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* addref & decref are atomic operations in many use-cases which
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* are expensive.
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*
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* - support non-blocking cfs_hash_add() and cfs_hash_findadd():
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* some lustre use-cases require these functions to be strictly
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* non-blocking, we need to schedule required rehash on a different
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* thread on those cases.
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*
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* - safer rehash on large hash table
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* In old implementation, rehash function will exclusively lock the
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* hash table and finish rehash in one batch, it's dangerous on SMP
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* system because rehash millions of elements could take long time.
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* New implemented rehash can release lock and relax CPU in middle
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* of rehash, it's safe for another thread to search/change on the
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* hash table even it's in rehasing.
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*
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* - support two different refcount modes
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* . hash table has refcount on element
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* . hash table doesn't change refcount on adding/removing element
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*
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* - support long name hash table (for param-tree)
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*
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* - fix a bug for cfs_hash_rehash_key:
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* in old implementation, cfs_hash_rehash_key could screw up the
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* hash-table because @key is overwritten without any protection.
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* Now we need user to define hs_keycpy for those rehash enabled
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* hash tables, cfs_hash_rehash_key will overwrite hash-key
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* inside lock by calling hs_keycpy.
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*
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* - better hash iteration:
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* Now we support both locked iteration & lockless iteration of hash
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* table. Also, user can break the iteration by return 1 in callback.
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*/
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#include <linux/seq_file.h>
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#include <linux/log2.h>
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#include "../../include/linux/libcfs/libcfs.h"
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#if CFS_HASH_DEBUG_LEVEL >= CFS_HASH_DEBUG_1
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static unsigned int warn_on_depth = 8;
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module_param(warn_on_depth, uint, 0644);
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MODULE_PARM_DESC(warn_on_depth, "warning when hash depth is high.");
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#endif
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struct cfs_wi_sched *cfs_sched_rehash;
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static inline void
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cfs_hash_nl_lock(union cfs_hash_lock *lock, int exclusive) {}
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static inline void
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cfs_hash_nl_unlock(union cfs_hash_lock *lock, int exclusive) {}
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static inline void
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cfs_hash_spin_lock(union cfs_hash_lock *lock, int exclusive)
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__acquires(&lock->spin)
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{
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spin_lock(&lock->spin);
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}
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static inline void
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cfs_hash_spin_unlock(union cfs_hash_lock *lock, int exclusive)
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__releases(&lock->spin)
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{
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spin_unlock(&lock->spin);
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}
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static inline void
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cfs_hash_rw_lock(union cfs_hash_lock *lock, int exclusive)
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__acquires(&lock->rw)
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{
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if (!exclusive)
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read_lock(&lock->rw);
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else
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write_lock(&lock->rw);
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}
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static inline void
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cfs_hash_rw_unlock(union cfs_hash_lock *lock, int exclusive)
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__releases(&lock->rw)
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{
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if (!exclusive)
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read_unlock(&lock->rw);
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else
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write_unlock(&lock->rw);
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}
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/** No lock hash */
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static struct cfs_hash_lock_ops cfs_hash_nl_lops = {
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.hs_lock = cfs_hash_nl_lock,
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.hs_unlock = cfs_hash_nl_unlock,
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.hs_bkt_lock = cfs_hash_nl_lock,
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.hs_bkt_unlock = cfs_hash_nl_unlock,
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};
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/** no bucket lock, one spinlock to protect everything */
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static struct cfs_hash_lock_ops cfs_hash_nbl_lops = {
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.hs_lock = cfs_hash_spin_lock,
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.hs_unlock = cfs_hash_spin_unlock,
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.hs_bkt_lock = cfs_hash_nl_lock,
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.hs_bkt_unlock = cfs_hash_nl_unlock,
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};
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/** spin bucket lock, rehash is enabled */
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static struct cfs_hash_lock_ops cfs_hash_bkt_spin_lops = {
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.hs_lock = cfs_hash_rw_lock,
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.hs_unlock = cfs_hash_rw_unlock,
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.hs_bkt_lock = cfs_hash_spin_lock,
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.hs_bkt_unlock = cfs_hash_spin_unlock,
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};
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/** rw bucket lock, rehash is enabled */
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static struct cfs_hash_lock_ops cfs_hash_bkt_rw_lops = {
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.hs_lock = cfs_hash_rw_lock,
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.hs_unlock = cfs_hash_rw_unlock,
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.hs_bkt_lock = cfs_hash_rw_lock,
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.hs_bkt_unlock = cfs_hash_rw_unlock,
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};
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/** spin bucket lock, rehash is disabled */
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static struct cfs_hash_lock_ops cfs_hash_nr_bkt_spin_lops = {
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.hs_lock = cfs_hash_nl_lock,
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.hs_unlock = cfs_hash_nl_unlock,
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.hs_bkt_lock = cfs_hash_spin_lock,
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.hs_bkt_unlock = cfs_hash_spin_unlock,
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};
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/** rw bucket lock, rehash is disabled */
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static struct cfs_hash_lock_ops cfs_hash_nr_bkt_rw_lops = {
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.hs_lock = cfs_hash_nl_lock,
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.hs_unlock = cfs_hash_nl_unlock,
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.hs_bkt_lock = cfs_hash_rw_lock,
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.hs_bkt_unlock = cfs_hash_rw_unlock,
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};
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static void
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cfs_hash_lock_setup(struct cfs_hash *hs)
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{
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if (cfs_hash_with_no_lock(hs)) {
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hs->hs_lops = &cfs_hash_nl_lops;
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} else if (cfs_hash_with_no_bktlock(hs)) {
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hs->hs_lops = &cfs_hash_nbl_lops;
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spin_lock_init(&hs->hs_lock.spin);
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} else if (cfs_hash_with_rehash(hs)) {
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rwlock_init(&hs->hs_lock.rw);
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if (cfs_hash_with_rw_bktlock(hs))
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hs->hs_lops = &cfs_hash_bkt_rw_lops;
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else if (cfs_hash_with_spin_bktlock(hs))
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hs->hs_lops = &cfs_hash_bkt_spin_lops;
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else
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LBUG();
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} else {
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if (cfs_hash_with_rw_bktlock(hs))
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hs->hs_lops = &cfs_hash_nr_bkt_rw_lops;
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else if (cfs_hash_with_spin_bktlock(hs))
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hs->hs_lops = &cfs_hash_nr_bkt_spin_lops;
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else
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LBUG();
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}
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}
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/**
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* Simple hash head without depth tracking
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* new element is always added to head of hlist
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*/
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struct cfs_hash_head {
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struct hlist_head hh_head; /**< entries list */
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};
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static int
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cfs_hash_hh_hhead_size(struct cfs_hash *hs)
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{
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return sizeof(struct cfs_hash_head);
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}
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static struct hlist_head *
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cfs_hash_hh_hhead(struct cfs_hash *hs, struct cfs_hash_bd *bd)
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{
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struct cfs_hash_head *head;
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head = (struct cfs_hash_head *)&bd->bd_bucket->hsb_head[0];
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return &head[bd->bd_offset].hh_head;
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}
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static int
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cfs_hash_hh_hnode_add(struct cfs_hash *hs, struct cfs_hash_bd *bd,
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struct hlist_node *hnode)
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{
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hlist_add_head(hnode, cfs_hash_hh_hhead(hs, bd));
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return -1; /* unknown depth */
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}
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static int
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cfs_hash_hh_hnode_del(struct cfs_hash *hs, struct cfs_hash_bd *bd,
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struct hlist_node *hnode)
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{
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hlist_del_init(hnode);
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return -1; /* unknown depth */
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}
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/**
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* Simple hash head with depth tracking
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* new element is always added to head of hlist
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*/
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struct cfs_hash_head_dep {
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struct hlist_head hd_head; /**< entries list */
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unsigned int hd_depth; /**< list length */
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};
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static int
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cfs_hash_hd_hhead_size(struct cfs_hash *hs)
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{
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return sizeof(struct cfs_hash_head_dep);
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}
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static struct hlist_head *
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cfs_hash_hd_hhead(struct cfs_hash *hs, struct cfs_hash_bd *bd)
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{
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struct cfs_hash_head_dep *head;
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head = (struct cfs_hash_head_dep *)&bd->bd_bucket->hsb_head[0];
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return &head[bd->bd_offset].hd_head;
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}
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static int
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cfs_hash_hd_hnode_add(struct cfs_hash *hs, struct cfs_hash_bd *bd,
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struct hlist_node *hnode)
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{
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struct cfs_hash_head_dep *hh;
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hh = container_of(cfs_hash_hd_hhead(hs, bd),
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struct cfs_hash_head_dep, hd_head);
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hlist_add_head(hnode, &hh->hd_head);
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return ++hh->hd_depth;
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}
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static int
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cfs_hash_hd_hnode_del(struct cfs_hash *hs, struct cfs_hash_bd *bd,
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struct hlist_node *hnode)
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{
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struct cfs_hash_head_dep *hh;
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hh = container_of(cfs_hash_hd_hhead(hs, bd),
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struct cfs_hash_head_dep, hd_head);
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hlist_del_init(hnode);
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return --hh->hd_depth;
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}
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/**
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* double links hash head without depth tracking
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* new element is always added to tail of hlist
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*/
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struct cfs_hash_dhead {
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struct hlist_head dh_head; /**< entries list */
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struct hlist_node *dh_tail; /**< the last entry */
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};
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static int
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cfs_hash_dh_hhead_size(struct cfs_hash *hs)
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{
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return sizeof(struct cfs_hash_dhead);
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}
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static struct hlist_head *
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cfs_hash_dh_hhead(struct cfs_hash *hs, struct cfs_hash_bd *bd)
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{
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struct cfs_hash_dhead *head;
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head = (struct cfs_hash_dhead *)&bd->bd_bucket->hsb_head[0];
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return &head[bd->bd_offset].dh_head;
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}
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static int
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cfs_hash_dh_hnode_add(struct cfs_hash *hs, struct cfs_hash_bd *bd,
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struct hlist_node *hnode)
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{
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struct cfs_hash_dhead *dh;
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dh = container_of(cfs_hash_dh_hhead(hs, bd),
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struct cfs_hash_dhead, dh_head);
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if (dh->dh_tail) /* not empty */
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hlist_add_behind(hnode, dh->dh_tail);
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else /* empty list */
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hlist_add_head(hnode, &dh->dh_head);
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dh->dh_tail = hnode;
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return -1; /* unknown depth */
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}
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static int
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cfs_hash_dh_hnode_del(struct cfs_hash *hs, struct cfs_hash_bd *bd,
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struct hlist_node *hnd)
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{
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struct cfs_hash_dhead *dh;
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dh = container_of(cfs_hash_dh_hhead(hs, bd),
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struct cfs_hash_dhead, dh_head);
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if (!hnd->next) { /* it's the tail */
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dh->dh_tail = (hnd->pprev == &dh->dh_head.first) ? NULL :
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container_of(hnd->pprev, struct hlist_node, next);
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}
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hlist_del_init(hnd);
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return -1; /* unknown depth */
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}
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/**
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* double links hash head with depth tracking
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* new element is always added to tail of hlist
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*/
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struct cfs_hash_dhead_dep {
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struct hlist_head dd_head; /**< entries list */
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struct hlist_node *dd_tail; /**< the last entry */
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unsigned int dd_depth; /**< list length */
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};
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static int
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cfs_hash_dd_hhead_size(struct cfs_hash *hs)
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{
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return sizeof(struct cfs_hash_dhead_dep);
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}
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static struct hlist_head *
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cfs_hash_dd_hhead(struct cfs_hash *hs, struct cfs_hash_bd *bd)
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{
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struct cfs_hash_dhead_dep *head;
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head = (struct cfs_hash_dhead_dep *)&bd->bd_bucket->hsb_head[0];
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return &head[bd->bd_offset].dd_head;
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}
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static int
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cfs_hash_dd_hnode_add(struct cfs_hash *hs, struct cfs_hash_bd *bd,
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struct hlist_node *hnode)
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{
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struct cfs_hash_dhead_dep *dh;
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dh = container_of(cfs_hash_dd_hhead(hs, bd),
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struct cfs_hash_dhead_dep, dd_head);
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if (dh->dd_tail) /* not empty */
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hlist_add_behind(hnode, dh->dd_tail);
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else /* empty list */
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hlist_add_head(hnode, &dh->dd_head);
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dh->dd_tail = hnode;
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return ++dh->dd_depth;
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}
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static int
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cfs_hash_dd_hnode_del(struct cfs_hash *hs, struct cfs_hash_bd *bd,
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struct hlist_node *hnd)
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{
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struct cfs_hash_dhead_dep *dh;
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dh = container_of(cfs_hash_dd_hhead(hs, bd),
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struct cfs_hash_dhead_dep, dd_head);
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if (!hnd->next) { /* it's the tail */
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dh->dd_tail = (hnd->pprev == &dh->dd_head.first) ? NULL :
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container_of(hnd->pprev, struct hlist_node, next);
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}
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hlist_del_init(hnd);
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return --dh->dd_depth;
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}
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static struct cfs_hash_hlist_ops cfs_hash_hh_hops = {
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.hop_hhead = cfs_hash_hh_hhead,
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.hop_hhead_size = cfs_hash_hh_hhead_size,
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.hop_hnode_add = cfs_hash_hh_hnode_add,
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.hop_hnode_del = cfs_hash_hh_hnode_del,
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};
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static struct cfs_hash_hlist_ops cfs_hash_hd_hops = {
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.hop_hhead = cfs_hash_hd_hhead,
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.hop_hhead_size = cfs_hash_hd_hhead_size,
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.hop_hnode_add = cfs_hash_hd_hnode_add,
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.hop_hnode_del = cfs_hash_hd_hnode_del,
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};
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static struct cfs_hash_hlist_ops cfs_hash_dh_hops = {
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.hop_hhead = cfs_hash_dh_hhead,
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.hop_hhead_size = cfs_hash_dh_hhead_size,
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.hop_hnode_add = cfs_hash_dh_hnode_add,
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.hop_hnode_del = cfs_hash_dh_hnode_del,
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};
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static struct cfs_hash_hlist_ops cfs_hash_dd_hops = {
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.hop_hhead = cfs_hash_dd_hhead,
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.hop_hhead_size = cfs_hash_dd_hhead_size,
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.hop_hnode_add = cfs_hash_dd_hnode_add,
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.hop_hnode_del = cfs_hash_dd_hnode_del,
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};
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static void
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cfs_hash_hlist_setup(struct cfs_hash *hs)
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{
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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)) {
|
|
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++;
|
|
}
|
|
|
|
enum {
|
|
/** always set, for sanity (avoid ZERO intent) */
|
|
CFS_HS_LOOKUP_MASK_FIND = BIT(0),
|
|
/** return entry with a ref */
|
|
CFS_HS_LOOKUP_MASK_REF = BIT(1),
|
|
/** add entry if not existing */
|
|
CFS_HS_LOOKUP_MASK_ADD = BIT(2),
|
|
/** delete entry, ignore other masks */
|
|
CFS_HS_LOOKUP_MASK_DEL = BIT(3),
|
|
};
|
|
|
|
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)
|
|
};
|
|
|
|
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,
|
|
enum cfs_hash_lookup_intent 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 && 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);
|
|
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);
|
|
|
|
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 || 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)
|
|
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);
|
|
intent = (!noref * CFS_HS_LOOKUP_MASK_REF) | CFS_HS_LOOKUP_IT_PEEK;
|
|
|
|
cfs_hash_for_each_bd(bds, n, i) {
|
|
ehnode = cfs_hash_bd_lookup_intent(hs, &bds[i], key,
|
|
NULL, intent);
|
|
if (ehnode)
|
|
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 int 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)
|
|
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)
|
|
return;
|
|
|
|
if (!bd1->bd_bucket) {
|
|
*bd1 = *bd2;
|
|
bd2->bd_bucket = NULL;
|
|
return;
|
|
}
|
|
|
|
rc = cfs_hash_bd_compare(bd1, bd2);
|
|
if (!rc)
|
|
bd2->bd_bucket = NULL;
|
|
else if (rc > 0)
|
|
swap(*bd1, *bd2); /* swap bd1 and bd2 */
|
|
}
|
|
|
|
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)) {
|
|
/* 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]);
|
|
}
|
|
|
|
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);
|
|
}
|
|
|
|
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);
|
|
}
|
|
|
|
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);
|
|
}
|
|
|
|
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);
|
|
}
|
|
|
|
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);
|
|
}
|
|
|
|
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])
|
|
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);
|
|
|
|
if (old_bkts && old_size == new_size)
|
|
return old_bkts;
|
|
|
|
LIBCFS_ALLOC(new_bkts, sizeof(new_bkts[0]) * new_size);
|
|
if (!new_bkts)
|
|
return NULL;
|
|
|
|
if (old_bkts) {
|
|
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]) {
|
|
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,
|
|
struct cfs_hash_ops *ops, unsigned flags)
|
|
{
|
|
struct cfs_hash *hs;
|
|
int len;
|
|
|
|
CLASSERT(CFS_HASH_THETA_BITS < 15);
|
|
|
|
LASSERT(name);
|
|
LASSERT(ops->hs_key);
|
|
LASSERT(ops->hs_hash);
|
|
LASSERT(ops->hs_object);
|
|
LASSERT(ops->hs_keycmp);
|
|
LASSERT(ops->hs_get);
|
|
LASSERT(ops->hs_put_locked);
|
|
|
|
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));
|
|
|
|
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)
|
|
return NULL;
|
|
|
|
strlcpy(hs->hs_name, name, len);
|
|
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)
|
|
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);
|
|
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 && !hs->hs_rehash_buckets);
|
|
|
|
cfs_hash_for_each_bucket(hs, &bd, i) {
|
|
struct hlist_head *hhead;
|
|
|
|
LASSERT(bd.bd_bucket);
|
|
/* 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 || !hlist_unhashed(hnode)) {
|
|
if (!bds[1].bd_bucket && hnode) {
|
|
cfs_hash_bd_del_locked(hs, &bds[0], hnode);
|
|
} else {
|
|
hnode = cfs_hash_dual_bd_finddel_locked(hs, bds,
|
|
key, hnode);
|
|
}
|
|
}
|
|
|
|
if (hnode) {
|
|
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)
|
|
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) { /* 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;
|
|
}
|
|
|
|
struct cfs_hash_cond_arg {
|
|
cfs_hash_cond_opt_cb_t func;
|
|
void *arg;
|
|
};
|
|
|
|
static int
|
|
cfs_hash_cond_del_locked(struct cfs_hash *hs, struct cfs_hash_bd *bd,
|
|
struct hlist_node *hnode, void *data)
|
|
{
|
|
struct cfs_hash_cond_arg *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)
|
|
{
|
|
struct cfs_hash_cond_arg 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) ||
|
|
!hs->hs_ops->hs_put_locked;
|
|
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;) {
|
|
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;
|
|
}
|
|
if (rc) /* callback wants to break iteration */
|
|
break;
|
|
}
|
|
cfs_hash_bd_unlock(hs, &bd, 0);
|
|
if (rc) /* callback wants to break iteration */
|
|
break;
|
|
}
|
|
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 (!hs->hs_ops->hs_get ||
|
|
(!hs->hs_ops->hs_put && !hs->hs_ops->hs_put_locked))
|
|
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 (!hs->hs_ops->hs_get ||
|
|
(!hs->hs_ops->hs_put && !hs->hs_ops->hs_put_locked))
|
|
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 int 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_power_of_2(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);
|
|
}
|
|
}
|
|
|
|
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);
|
|
}
|
|
|
|
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);
|
|
}
|
|
|
|
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);
|
|
/* 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 && 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) {
|
|
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);
|
|
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)
|
|
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)) {
|
|
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, hnode, new_key);
|
|
|
|
cfs_hash_multi_bd_unlock(hs, bds, 3, 1);
|
|
cfs_hash_unlock(hs, 0);
|
|
}
|
|
EXPORT_SYMBOL(cfs_hash_rehash_key);
|
|
|
|
void cfs_hash_debug_header(struct seq_file *m)
|
|
{
|
|
seq_printf(m, "%-*s cur min max theta t-min t-max flags rehash count maxdep maxdepb distribution\n",
|
|
CFS_HASH_BIGNAME_LEN, "name");
|
|
}
|
|
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)
|
|
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)
|
|
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);
|
|
}
|
|
|
|
void 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(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);
|
|
}
|
|
EXPORT_SYMBOL(cfs_hash_debug_str);
|