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7 * it under the terms of the GNU General Public License version 2 only,
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13 * General Public License version 2 for more details (a copy is included
14 * in the LICENSE file that accompanied this code).
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17 * version 2 along with this program; If not, see
18 * http://www.gnu.org/licenses/gpl-2.0.html
23 * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
24 * Use is subject to license terms.
26 * Copyright (c) 2012, 2017, Intel Corporation.
29 * This file is part of Lustre, http://www.lustre.org/
30 * Lustre is a trademark of Sun Microsystems, Inc.
32 * lustre/obdclass/lu_ref.c
36 * Author: Nikita Danilov <nikita.danilov@sun.com>
39 #define DEBUG_SUBSYSTEM S_CLASS
41 #include <libcfs/libcfs.h>
43 #include <obd_class.h>
44 #include <obd_support.h>
50 * Asserts a condition for a given lu_ref. Must be called with
51 * lu_ref::lf_guard held.
53 #define REFASSERT(ref, expr) do { \
54 struct lu_ref *__tmp = (ref); \
56 if (unlikely(!(expr))) { \
57 lu_ref_print(__tmp); \
58 spin_unlock(&__tmp->lf_guard); \
61 spin_lock(&__tmp->lf_guard); \
65 static struct kmem_cache *lu_ref_link_kmem;
67 static struct lu_kmem_descr lu_ref_caches[] = {
69 .ckd_cache = &lu_ref_link_kmem,
70 .ckd_name = "lu_ref_link_kmem",
71 .ckd_size = sizeof(struct lu_ref_link)
79 * Global list of active (initialized, but not finalized) lu_ref's.
81 * Protected by lu_ref_refs_guard.
83 static LIST_HEAD(lu_ref_refs);
84 static DEFINE_SPINLOCK(lu_ref_refs_guard);
85 static struct lu_ref lu_ref_marker = {
86 .lf_guard = __SPIN_LOCK_UNLOCKED(lu_ref_marker.lf_guard),
87 .lf_list = LIST_HEAD_INIT(lu_ref_marker.lf_list),
88 .lf_linkage = LIST_HEAD_INIT(lu_ref_marker.lf_linkage)
91 void lu_ref_print(const struct lu_ref *ref)
93 struct lu_ref_link *link;
95 CERROR("lu_ref: %p %d %d %s:%d\n",
96 ref, ref->lf_refs, ref->lf_failed, ref->lf_func, ref->lf_line);
97 list_for_each_entry(link, &ref->lf_list, ll_linkage) {
98 CERROR(" link: %s %p\n", link->ll_scope, link->ll_source);
102 static int lu_ref_is_marker(const struct lu_ref *ref)
104 return ref == &lu_ref_marker;
107 void lu_ref_print_all(void)
111 spin_lock(&lu_ref_refs_guard);
112 list_for_each_entry(ref, &lu_ref_refs, lf_linkage) {
113 if (lu_ref_is_marker(ref))
116 spin_lock(&ref->lf_guard);
118 spin_unlock(&ref->lf_guard);
120 spin_unlock(&lu_ref_refs_guard);
123 void lu_ref_init_loc(struct lu_ref *ref, const char *func, const int line)
128 spin_lock_init(&ref->lf_guard);
129 INIT_LIST_HEAD(&ref->lf_list);
130 spin_lock(&lu_ref_refs_guard);
131 list_add(&ref->lf_linkage, &lu_ref_refs);
132 spin_unlock(&lu_ref_refs_guard);
134 EXPORT_SYMBOL(lu_ref_init_loc);
136 void lu_ref_fini(struct lu_ref *ref)
138 spin_lock(&ref->lf_guard);
139 REFASSERT(ref, list_empty(&ref->lf_list));
140 REFASSERT(ref, ref->lf_refs == 0);
141 spin_unlock(&ref->lf_guard);
142 spin_lock(&lu_ref_refs_guard);
143 list_del_init(&ref->lf_linkage);
144 spin_unlock(&lu_ref_refs_guard);
146 EXPORT_SYMBOL(lu_ref_fini);
148 static struct lu_ref_link *lu_ref_add_context(struct lu_ref *ref,
153 struct lu_ref_link *link;
156 if (lu_ref_link_kmem != NULL) {
157 OBD_SLAB_ALLOC_PTR_GFP(link, lu_ref_link_kmem, flags);
160 link->ll_scope = scope;
161 link->ll_source = source;
162 spin_lock(&ref->lf_guard);
163 list_add_tail(&link->ll_linkage, &ref->lf_list);
165 spin_unlock(&ref->lf_guard);
170 spin_lock(&ref->lf_guard);
172 spin_unlock(&ref->lf_guard);
173 link = ERR_PTR(-ENOMEM);
179 void lu_ref_add(struct lu_ref *ref, const char *scope, const void *source)
182 lu_ref_add_context(ref, GFP_NOFS, scope, source);
184 EXPORT_SYMBOL(lu_ref_add);
186 void lu_ref_add_at(struct lu_ref *ref, struct lu_ref_link *link,
187 const char *scope, const void *source)
190 link->ll_scope = scope;
191 link->ll_source = source;
192 spin_lock(&ref->lf_guard);
193 list_add_tail(&link->ll_linkage, &ref->lf_list);
195 spin_unlock(&ref->lf_guard);
197 EXPORT_SYMBOL(lu_ref_add_at);
200 * Version of lu_ref_add() to be used in non-blockable contexts.
202 void lu_ref_add_atomic(struct lu_ref *ref, const char *scope,
205 lu_ref_add_context(ref, GFP_ATOMIC, scope, source);
207 EXPORT_SYMBOL(lu_ref_add_atomic);
209 static inline int lu_ref_link_eq(const struct lu_ref_link *link,
213 return link->ll_source == source && !strcmp(link->ll_scope, scope);
217 * Maximal chain length seen so far.
219 static unsigned lu_ref_chain_max_length = 127;
222 * Searches for a lu_ref_link with given [scope, source] within given lu_ref.
224 static struct lu_ref_link *lu_ref_find(struct lu_ref *ref, const char *scope,
227 struct lu_ref_link *link;
228 unsigned int iterations;
231 list_for_each_entry(link, &ref->lf_list, ll_linkage) {
233 if (lu_ref_link_eq(link, scope, source)) {
234 if (iterations > lu_ref_chain_max_length) {
235 CWARN("Long lu_ref chain %d \"%s\":%p\n",
236 iterations, scope, source);
237 lu_ref_chain_max_length = iterations * 3 / 2;
245 void lu_ref_del(struct lu_ref *ref, const char *scope, const void *source)
247 struct lu_ref_link *link;
249 spin_lock(&ref->lf_guard);
250 link = lu_ref_find(ref, scope, source);
252 list_del(&link->ll_linkage);
254 spin_unlock(&ref->lf_guard);
255 OBD_SLAB_FREE(link, lu_ref_link_kmem, sizeof(*link));
257 REFASSERT(ref, ref->lf_failed > 0);
259 spin_unlock(&ref->lf_guard);
262 EXPORT_SYMBOL(lu_ref_del);
264 void lu_ref_set_at(struct lu_ref *ref, struct lu_ref_link *link,
266 const void *source0, const void *source1)
268 spin_lock(&ref->lf_guard);
269 REFASSERT(ref, link != NULL && !IS_ERR(link));
270 REFASSERT(ref, link->ll_ref == ref);
271 REFASSERT(ref, lu_ref_link_eq(link, scope, source0));
272 link->ll_source = source1;
273 spin_unlock(&ref->lf_guard);
275 EXPORT_SYMBOL(lu_ref_set_at);
277 void lu_ref_del_at(struct lu_ref *ref, struct lu_ref_link *link,
278 const char *scope, const void *source)
280 spin_lock(&ref->lf_guard);
281 REFASSERT(ref, link != NULL && !IS_ERR(link));
282 REFASSERT(ref, link->ll_ref == ref);
283 REFASSERT(ref, lu_ref_link_eq(link, scope, source));
284 list_del(&link->ll_linkage);
286 spin_unlock(&ref->lf_guard);
288 EXPORT_SYMBOL(lu_ref_del_at);
290 #ifdef CONFIG_PROC_FS
292 static void *lu_ref_seq_start(struct seq_file *seq, loff_t *pos)
294 struct lu_ref *ref = seq->private;
296 spin_lock(&lu_ref_refs_guard);
297 if (list_empty(&ref->lf_linkage))
299 spin_unlock(&lu_ref_refs_guard);
304 static void *lu_ref_seq_next(struct seq_file *seq, void *p, loff_t *pos)
306 struct lu_ref *ref = p;
309 LASSERT(seq->private == p);
310 LASSERT(!list_empty(&ref->lf_linkage));
312 spin_lock(&lu_ref_refs_guard);
313 next = list_entry(ref->lf_linkage.next, struct lu_ref, lf_linkage);
314 if (&next->lf_linkage == &lu_ref_refs) {
318 list_move(&ref->lf_linkage, &next->lf_linkage);
320 spin_unlock(&lu_ref_refs_guard);
324 static void lu_ref_seq_stop(struct seq_file *seq, void *p)
330 static int lu_ref_seq_show(struct seq_file *seq, void *p)
332 struct lu_ref *ref = p;
335 spin_lock(&lu_ref_refs_guard);
336 next = list_entry(ref->lf_linkage.next, struct lu_ref, lf_linkage);
337 if ((&next->lf_linkage == &lu_ref_refs) || lu_ref_is_marker(next)) {
338 spin_unlock(&lu_ref_refs_guard);
342 /* print the entry */
343 spin_lock(&next->lf_guard);
344 seq_printf(seq, "lu_ref: %p %d %d %s:%d\n",
345 next, next->lf_refs, next->lf_failed,
346 next->lf_func, next->lf_line);
347 if (next->lf_refs > 64) {
348 seq_puts(seq, " too many references, skip\n");
350 struct lu_ref_link *link;
353 list_for_each_entry(link, &next->lf_list, ll_linkage)
354 seq_printf(seq, " #%d link: %s %p\n",
355 i++, link->ll_scope, link->ll_source);
357 spin_unlock(&next->lf_guard);
358 spin_unlock(&lu_ref_refs_guard);
363 static struct seq_operations lu_ref_seq_ops = {
364 .start = lu_ref_seq_start,
365 .stop = lu_ref_seq_stop,
366 .next = lu_ref_seq_next,
367 .show = lu_ref_seq_show
370 static int lu_ref_seq_open(struct inode *inode, struct file *file)
372 struct lu_ref *marker = &lu_ref_marker;
375 result = seq_open(file, &lu_ref_seq_ops);
377 spin_lock(&lu_ref_refs_guard);
378 if (!list_empty(&marker->lf_linkage))
381 list_add(&marker->lf_linkage, &lu_ref_refs);
382 spin_unlock(&lu_ref_refs_guard);
385 struct seq_file *f = file->private_data;
389 seq_release(inode, file);
396 static int lu_ref_seq_release(struct inode *inode, struct file *file)
398 struct lu_ref *ref = ((struct seq_file *)file->private_data)->private;
400 spin_lock(&lu_ref_refs_guard);
401 list_del_init(&ref->lf_linkage);
402 spin_unlock(&lu_ref_refs_guard);
404 return seq_release(inode, file);
407 static struct file_operations lu_ref_dump_fops = {
408 .owner = THIS_MODULE,
409 .open = lu_ref_seq_open,
412 .release = lu_ref_seq_release
415 #endif /* CONFIG_PROC_FS */
417 int lu_ref_global_init(void)
422 "lu_ref tracking is enabled. Performance isn't.\n");
424 result = lu_kmem_init(lu_ref_caches);
426 #ifdef CONFIG_PROC_FS
428 result = lprocfs_seq_create(proc_lustre_root, "lu_refs",
429 0444, &lu_ref_dump_fops, NULL);
431 lu_kmem_fini(lu_ref_caches);
433 #endif /* CONFIG_PROC_FS */
438 void lu_ref_global_fini(void)
440 #ifdef CONFIG_PROC_FS
441 lprocfs_remove_proc_entry("lu_refs", proc_lustre_root);
442 #endif /* CONFIG_PROC_FS */
443 lu_kmem_fini(lu_ref_caches);
446 #endif /* USE_LU_REF */