4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 only,
8 * as published by the Free Software Foundation.
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * General Public License version 2 for more details (a copy is included
14 * in the LICENSE file that accompanied this code).
16 * You should have received a copy of the GNU General Public License
17 * version 2 along with this program; if not, write to the
18 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
19 * Boston, MA 021110-1307, USA
23 /* Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
24 * Copyright (c) 2012, 2015, Intel Corporation.
27 * This file is part of Lustre, http://www.lustre.org/
29 * Author: liang@whamcloud.com
32 #define DEBUG_SUBSYSTEM S_LNET
34 #include <libcfs/libcfs.h>
36 /** destroy cpu-partition lock, see libcfs_private.h for more detail */
38 cfs_percpt_lock_free(struct cfs_percpt_lock *pcl)
40 LASSERT(pcl->pcl_locks != NULL);
41 LASSERT(!pcl->pcl_locked);
43 cfs_percpt_free(pcl->pcl_locks);
44 LIBCFS_FREE(pcl, sizeof(*pcl));
46 EXPORT_SYMBOL(cfs_percpt_lock_free);
49 * create cpu-partition lock, see libcfs_private.h for more detail.
51 * cpu-partition lock is designed for large-scale SMP system, so we need to
52 * reduce cacheline conflict as possible as we can, that's the
53 * reason we always allocate cacheline-aligned memory block.
55 struct cfs_percpt_lock *
56 cfs_percpt_lock_create(struct cfs_cpt_table *cptab,
57 struct lock_class_key *keys)
59 struct cfs_percpt_lock *pcl;
63 /* NB: cptab can be NULL, pcl will be for HW CPUs on that case */
64 LIBCFS_ALLOC(pcl, sizeof(*pcl));
68 pcl->pcl_cptab = cptab;
69 pcl->pcl_locks = cfs_percpt_alloc(cptab, sizeof(*lock));
70 if (pcl->pcl_locks == NULL) {
71 LIBCFS_FREE(pcl, sizeof(*pcl));
76 CWARN("Cannot setup class key for percpt lock, you may see "
77 "recursive locking warnings which are actually fake.\n");
80 cfs_percpt_for_each(lock, i, pcl->pcl_locks) {
83 lockdep_set_class(lock, &keys[i]);
88 EXPORT_SYMBOL(cfs_percpt_lock_create);
91 * lock a CPU partition
93 * \a index != CFS_PERCPT_LOCK_EX
94 * hold private lock indexed by \a index
96 * \a index == CFS_PERCPT_LOCK_EX
97 * exclusively lock @pcl and nobody can take private lock
100 cfs_percpt_lock(struct cfs_percpt_lock *pcl, int index)
101 __acquires(pcl->pcl_locks)
103 int ncpt = cfs_cpt_number(pcl->pcl_cptab);
106 LASSERT(index >= CFS_PERCPT_LOCK_EX && index < ncpt);
110 } else { /* serialize with exclusive lock */
111 while (pcl->pcl_locked)
115 if (likely(index != CFS_PERCPT_LOCK_EX)) {
116 spin_lock(pcl->pcl_locks[index]);
120 /* exclusive lock request */
121 for (i = 0; i < ncpt; i++) {
122 spin_lock(pcl->pcl_locks[i]);
124 LASSERT(!pcl->pcl_locked);
125 /* nobody should take private lock after this
126 * so I wouldn't starve for too long time */
131 EXPORT_SYMBOL(cfs_percpt_lock);
133 /** unlock a CPU partition */
135 cfs_percpt_unlock(struct cfs_percpt_lock *pcl, int index)
136 __releases(pcl->pcl_locks)
138 int ncpt = cfs_cpt_number(pcl->pcl_cptab);
141 index = ncpt == 1 ? 0 : index;
143 if (likely(index != CFS_PERCPT_LOCK_EX)) {
144 spin_unlock(pcl->pcl_locks[index]);
148 for (i = ncpt - 1; i >= 0; i--) {
150 LASSERT(pcl->pcl_locked);
153 spin_unlock(pcl->pcl_locks[i]);
156 EXPORT_SYMBOL(cfs_percpt_unlock);