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).
18 /* Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
19 * Copyright (c) 2012, 2015, Intel Corporation.
21 /* This file is part of Lustre, http://www.lustre.org/
23 * Author: liang@whamcloud.com
26 #define DEBUG_SUBSYSTEM S_LNET
28 #include <lnet/lib-lnet.h>
30 /** destroy cpu-partition lock, see libcfs_private.h for more detail */
32 cfs_percpt_lock_free(struct cfs_percpt_lock *pcl)
34 LASSERT(pcl->pcl_locks != NULL);
35 LASSERT(!pcl->pcl_locked);
37 cfs_percpt_free(pcl->pcl_locks);
38 LIBCFS_FREE(pcl, sizeof(*pcl));
40 EXPORT_SYMBOL(cfs_percpt_lock_free);
43 * create cpu-partition lock, see libcfs_private.h for more detail.
45 * cpu-partition lock is designed for large-scale SMP system, so we need to
46 * reduce cacheline conflict as possible as we can, that's the
47 * reason we always allocate cacheline-aligned memory block.
49 struct cfs_percpt_lock *
50 cfs_percpt_lock_create(struct cfs_cpt_table *cptab,
51 struct lock_class_key *keys)
53 struct cfs_percpt_lock *pcl;
57 /* NB: cptab can be NULL, pcl will be for HW CPUs on that case */
58 LIBCFS_ALLOC(pcl, sizeof(*pcl));
62 pcl->pcl_cptab = cptab;
63 pcl->pcl_locks = cfs_percpt_alloc(cptab, sizeof(*lock));
64 if (pcl->pcl_locks == NULL) {
65 LIBCFS_FREE(pcl, sizeof(*pcl));
70 CWARN("Cannot setup class key for percpt lock, you may see recursive locking warnings which are actually fake.\n");
73 cfs_percpt_for_each(lock, i, pcl->pcl_locks) {
76 lockdep_set_class(lock, &keys[i]);
81 EXPORT_SYMBOL(cfs_percpt_lock_create);
84 * lock a CPU partition
86 * \a index != CFS_PERCPT_LOCK_EX
87 * hold private lock indexed by \a index
89 * \a index == CFS_PERCPT_LOCK_EX
90 * exclusively lock @pcl and nobody can take private lock
93 cfs_percpt_lock(struct cfs_percpt_lock *pcl, int index)
94 __acquires(pcl->pcl_locks)
96 int ncpt = cfs_cpt_number(pcl->pcl_cptab);
99 LASSERT(index >= CFS_PERCPT_LOCK_EX && index < ncpt);
103 } else { /* serialize with exclusive lock */
104 while (pcl->pcl_locked)
108 if (likely(index != CFS_PERCPT_LOCK_EX)) {
109 spin_lock(pcl->pcl_locks[index]);
113 /* exclusive lock request */
114 for (i = 0; i < ncpt; i++) {
115 spin_lock(pcl->pcl_locks[i]);
117 LASSERT(!pcl->pcl_locked);
118 /* nobody should take private lock after this
119 * so I wouldn't starve for too long time
125 EXPORT_SYMBOL(cfs_percpt_lock);
127 /** unlock a CPU partition */
129 cfs_percpt_unlock(struct cfs_percpt_lock *pcl, int index)
130 __releases(pcl->pcl_locks)
132 int ncpt = cfs_cpt_number(pcl->pcl_cptab);
135 index = ncpt == 1 ? 0 : index;
137 if (likely(index != CFS_PERCPT_LOCK_EX)) {
138 spin_unlock(pcl->pcl_locks[index]);
142 for (i = ncpt - 1; i >= 0; i--) {
144 LASSERT(pcl->pcl_locked);
147 spin_unlock(pcl->pcl_locks[i]);
150 EXPORT_SYMBOL(cfs_percpt_unlock);