2 * Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
3 * Copyright (C) 2007 The Regents of the University of California.
4 * Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
5 * Written by Brian Behlendorf <behlendorf1@llnl.gov>.
8 * This file is part of the SPL, Solaris Porting Layer.
9 * For details, see <http://zfsonlinux.org/>.
11 * The SPL is free software; you can redistribute it and/or modify it
12 * under the terms of the GNU General Public License as published by the
13 * Free Software Foundation; either version 2 of the License, or (at your
14 * option) any later version.
16 * The SPL is distributed in the hope that it will be useful, but WITHOUT
17 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
18 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
21 * You should have received a copy of the GNU General Public License along
22 * with the SPL. If not, see <http://www.gnu.org/licenses/>.
25 #include <sys/debug.h>
26 #include <sys/sysmacros.h>
30 #include <linux/ratelimit.h>
33 * As a general rule kmem_alloc() allocations should be small, preferably
34 * just a few pages since they must by physically contiguous. Therefore, a
35 * rate limited warning will be printed to the console for any kmem_alloc()
36 * which exceeds a reasonable threshold.
38 * The default warning threshold is set to eight pages but capped at 32K to
39 * accommodate systems using large pages. This value was selected to be small
40 * enough to ensure the largest allocations are quickly noticed and fixed.
41 * But large enough to avoid logging any warnings when a allocation size is
42 * larger than optimal but not a serious concern. Since this value is tunable,
43 * developers are encouraged to set it lower when testing so any new largish
44 * allocations are quickly caught. These warnings may be disabled by setting
45 * the threshold to zero.
47 unsigned int spl_kmem_alloc_warn = MAX(8 * PAGE_SIZE, 32 * 1024);
48 module_param(spl_kmem_alloc_warn, uint, 0644);
49 MODULE_PARM_DESC(spl_kmem_alloc_warn,
50 "Warning threshold in bytes for a kmem_alloc()");
51 EXPORT_SYMBOL(spl_kmem_alloc_warn);
54 * Large kmem_alloc() allocations will fail if they exceed KMALLOC_MAX_SIZE.
55 * Allocations which are marginally smaller than this limit may succeed but
56 * should still be avoided due to the expense of locating a contiguous range
57 * of free pages. Therefore, a maximum kmem size with reasonable safely
58 * margin of 4x is set. Kmem_alloc() allocations larger than this maximum
59 * will quickly fail. Vmem_alloc() allocations less than or equal to this
60 * value will use kmalloc(), but shift to vmalloc() when exceeding this value.
62 unsigned int spl_kmem_alloc_max = (KMALLOC_MAX_SIZE >> 2);
63 module_param(spl_kmem_alloc_max, uint, 0644);
64 MODULE_PARM_DESC(spl_kmem_alloc_max,
65 "Maximum size in bytes for a kmem_alloc()");
66 EXPORT_SYMBOL(spl_kmem_alloc_max);
73 EXPORT_SYMBOL(kmem_debugging);
76 kmem_vasprintf(const char *fmt, va_list ap)
83 ptr = kvasprintf(kmem_flags_convert(KM_SLEEP), fmt, aq);
85 } while (ptr == NULL);
89 EXPORT_SYMBOL(kmem_vasprintf);
92 kmem_asprintf(const char *fmt, ...)
99 ptr = kvasprintf(kmem_flags_convert(KM_SLEEP), fmt, ap);
101 } while (ptr == NULL);
105 EXPORT_SYMBOL(kmem_asprintf);
108 __strdup(const char *str, int flags)
114 ptr = kmalloc(n + 1, kmem_flags_convert(flags));
116 memcpy(ptr, str, n + 1);
122 strdup(const char *str)
124 return (__strdup(str, KM_SLEEP));
126 EXPORT_SYMBOL(strdup);
133 EXPORT_SYMBOL(strfree);
136 * Limit the number of large allocation stack traces dumped to not more than
137 * 5 every 60 seconds to prevent denial-of-service attacks from debug code.
139 DEFINE_RATELIMIT_STATE(kmem_alloc_ratelimit_state, 60 * HZ, 5);
142 * General purpose unified implementation of kmem_alloc(). It is an
143 * amalgamation of Linux and Illumos allocator design. It should never be
144 * exported to ensure that code using kmem_alloc()/kmem_zalloc() remains
145 * relatively portable. Consumers may only access this function through
146 * wrappers that enforce the common flags to ensure portability.
149 spl_kmem_alloc_impl(size_t size, int flags, int node)
151 gfp_t lflags = kmem_flags_convert(flags);
156 * Log abnormally large allocations and rate limit the console output.
157 * Allocations larger than spl_kmem_alloc_warn should be performed
158 * through the vmem_alloc()/vmem_zalloc() interfaces.
160 if ((spl_kmem_alloc_warn > 0) && (size > spl_kmem_alloc_warn) &&
161 !(flags & KM_VMEM) && __ratelimit(&kmem_alloc_ratelimit_state)) {
163 "Large kmem_alloc(%lu, 0x%x), please file an issue at:\n"
164 "https://github.com/zfsonlinux/zfs/issues/new\n",
165 (unsigned long)size, flags);
170 * Use a loop because kmalloc_node() can fail when GFP_KERNEL is used
171 * unlike kmem_alloc() with KM_SLEEP on Illumos.
175 * Calling kmalloc_node() when the size >= spl_kmem_alloc_max
176 * is unsafe. This must fail for all for kmem_alloc() and
177 * kmem_zalloc() callers.
179 * For vmem_alloc() and vmem_zalloc() callers it is permissible
180 * to use __vmalloc(). However, in general use of __vmalloc()
181 * is strongly discouraged because a global lock must be
182 * acquired. Contention on this lock can significantly
183 * impact performance so frequently manipulating the virtual
184 * address space is strongly discouraged.
186 if ((size > spl_kmem_alloc_max) || use_vmem) {
187 if (flags & KM_VMEM) {
188 ptr = __vmalloc(size, lflags, PAGE_KERNEL);
193 ptr = kmalloc_node(size, lflags, node);
196 if (likely(ptr) || (flags & KM_NOSLEEP))
200 * For vmem_alloc() and vmem_zalloc() callers retry immediately
201 * using __vmalloc() which is unlikely to fail.
203 if ((flags & KM_VMEM) && (use_vmem == 0)) {
208 if (unlikely(__ratelimit(&kmem_alloc_ratelimit_state))) {
210 "Possible memory allocation deadlock: "
211 "size=%lu lflags=0x%x",
212 (unsigned long)size, lflags);
217 * Use cond_resched() instead of congestion_wait() to avoid
218 * deadlocking systems where there are no block devices.
227 spl_kmem_free_impl(const void *buf, size_t size)
229 if (is_vmalloc_addr(buf))
236 * Memory allocation and accounting for kmem_* * style allocations. When
237 * DEBUG_KMEM is enabled the total memory allocated will be tracked and
238 * any memory leaked will be reported during module unload.
240 * ./configure --enable-debug-kmem
244 /* Shim layer memory accounting */
245 #ifdef HAVE_ATOMIC64_T
246 atomic64_t kmem_alloc_used = ATOMIC64_INIT(0);
247 unsigned long long kmem_alloc_max = 0;
248 #else /* HAVE_ATOMIC64_T */
249 atomic_t kmem_alloc_used = ATOMIC_INIT(0);
250 unsigned long long kmem_alloc_max = 0;
251 #endif /* HAVE_ATOMIC64_T */
253 EXPORT_SYMBOL(kmem_alloc_used);
254 EXPORT_SYMBOL(kmem_alloc_max);
257 spl_kmem_alloc_debug(size_t size, int flags, int node)
261 ptr = spl_kmem_alloc_impl(size, flags, node);
263 kmem_alloc_used_add(size);
264 if (unlikely(kmem_alloc_used_read() > kmem_alloc_max))
265 kmem_alloc_max = kmem_alloc_used_read();
272 spl_kmem_free_debug(const void *ptr, size_t size)
274 kmem_alloc_used_sub(size);
275 spl_kmem_free_impl(ptr, size);
279 * When DEBUG_KMEM_TRACKING is enabled not only will total bytes be tracked
280 * but also the location of every alloc and free. When the SPL module is
281 * unloaded a list of all leaked addresses and where they were allocated
282 * will be dumped to the console. Enabling this feature has a significant
283 * impact on performance but it makes finding memory leaks straight forward.
285 * Not surprisingly with debugging enabled the xmem_locks are very highly
286 * contended particularly on xfree(). If we want to run with this detailed
287 * debugging enabled for anything other than debugging we need to minimize
288 * the contention by moving to a lock per xmem_table entry model.
290 * ./configure --enable-debug-kmem-tracking
292 #ifdef DEBUG_KMEM_TRACKING
294 #include <linux/hash.h>
295 #include <linux/ctype.h>
297 #define KMEM_HASH_BITS 10
298 #define KMEM_TABLE_SIZE (1 << KMEM_HASH_BITS)
300 typedef struct kmem_debug {
301 struct hlist_node kd_hlist; /* Hash node linkage */
302 struct list_head kd_list; /* List of all allocations */
303 void *kd_addr; /* Allocation pointer */
304 size_t kd_size; /* Allocation size */
305 const char *kd_func; /* Allocation function */
306 int kd_line; /* Allocation line */
309 static spinlock_t kmem_lock;
310 static struct hlist_head kmem_table[KMEM_TABLE_SIZE];
311 static struct list_head kmem_list;
313 static kmem_debug_t *
314 kmem_del_init(spinlock_t *lock, struct hlist_head *table,
315 int bits, const void *addr)
317 struct hlist_head *head;
318 struct hlist_node *node;
319 struct kmem_debug *p;
322 spin_lock_irqsave(lock, flags);
324 head = &table[hash_ptr((void *)addr, bits)];
325 hlist_for_each(node, head) {
326 p = list_entry(node, struct kmem_debug, kd_hlist);
327 if (p->kd_addr == addr) {
328 hlist_del_init(&p->kd_hlist);
329 list_del_init(&p->kd_list);
330 spin_unlock_irqrestore(lock, flags);
335 spin_unlock_irqrestore(lock, flags);
341 spl_kmem_alloc_track(size_t size, int flags,
342 const char *func, int line, int node)
346 unsigned long irq_flags;
348 dptr = kmalloc(sizeof (kmem_debug_t), kmem_flags_convert(flags));
352 dptr->kd_func = __strdup(func, flags);
353 if (dptr->kd_func == NULL) {
358 ptr = spl_kmem_alloc_debug(size, flags, node);
360 kfree(dptr->kd_func);
365 INIT_HLIST_NODE(&dptr->kd_hlist);
366 INIT_LIST_HEAD(&dptr->kd_list);
369 dptr->kd_size = size;
370 dptr->kd_line = line;
372 spin_lock_irqsave(&kmem_lock, irq_flags);
373 hlist_add_head(&dptr->kd_hlist,
374 &kmem_table[hash_ptr(ptr, KMEM_HASH_BITS)]);
375 list_add_tail(&dptr->kd_list, &kmem_list);
376 spin_unlock_irqrestore(&kmem_lock, irq_flags);
382 spl_kmem_free_track(const void *ptr, size_t size)
386 /* Ignore NULL pointer since we haven't tracked it at all*/
390 /* Must exist in hash due to kmem_alloc() */
391 dptr = kmem_del_init(&kmem_lock, kmem_table, KMEM_HASH_BITS, ptr);
392 ASSERT3P(dptr, !=, NULL);
393 ASSERT3S(dptr->kd_size, ==, size);
395 kfree(dptr->kd_func);
398 spl_kmem_free_debug(ptr, size);
400 #endif /* DEBUG_KMEM_TRACKING */
401 #endif /* DEBUG_KMEM */
404 * Public kmem_alloc(), kmem_zalloc() and kmem_free() interfaces.
407 spl_kmem_alloc(size_t size, int flags, const char *func, int line)
409 ASSERT0(flags & ~KM_PUBLIC_MASK);
411 #if !defined(DEBUG_KMEM)
412 return (spl_kmem_alloc_impl(size, flags, NUMA_NO_NODE));
413 #elif !defined(DEBUG_KMEM_TRACKING)
414 return (spl_kmem_alloc_debug(size, flags, NUMA_NO_NODE));
416 return (spl_kmem_alloc_track(size, flags, func, line, NUMA_NO_NODE));
419 EXPORT_SYMBOL(spl_kmem_alloc);
422 spl_kmem_zalloc(size_t size, int flags, const char *func, int line)
424 ASSERT0(flags & ~KM_PUBLIC_MASK);
428 #if !defined(DEBUG_KMEM)
429 return (spl_kmem_alloc_impl(size, flags, NUMA_NO_NODE));
430 #elif !defined(DEBUG_KMEM_TRACKING)
431 return (spl_kmem_alloc_debug(size, flags, NUMA_NO_NODE));
433 return (spl_kmem_alloc_track(size, flags, func, line, NUMA_NO_NODE));
436 EXPORT_SYMBOL(spl_kmem_zalloc);
439 spl_kmem_free(const void *buf, size_t size)
441 #if !defined(DEBUG_KMEM)
442 return (spl_kmem_free_impl(buf, size));
443 #elif !defined(DEBUG_KMEM_TRACKING)
444 return (spl_kmem_free_debug(buf, size));
446 return (spl_kmem_free_track(buf, size));
449 EXPORT_SYMBOL(spl_kmem_free);
451 #if defined(DEBUG_KMEM) && defined(DEBUG_KMEM_TRACKING)
453 spl_sprintf_addr(kmem_debug_t *kd, char *str, int len, int min)
455 int size = ((len - 1) < kd->kd_size) ? (len - 1) : kd->kd_size;
458 ASSERT(str != NULL && len >= 17);
462 * Check for a fully printable string, and while we are at
463 * it place the printable characters in the passed buffer.
465 for (i = 0; i < size; i++) {
466 str[i] = ((char *)(kd->kd_addr))[i];
467 if (isprint(str[i])) {
471 * Minimum number of printable characters found
472 * to make it worthwhile to print this as ascii.
483 sprintf(str, "%02x%02x%02x%02x%02x%02x%02x%02x",
484 *((uint8_t *)kd->kd_addr),
485 *((uint8_t *)kd->kd_addr + 2),
486 *((uint8_t *)kd->kd_addr + 4),
487 *((uint8_t *)kd->kd_addr + 6),
488 *((uint8_t *)kd->kd_addr + 8),
489 *((uint8_t *)kd->kd_addr + 10),
490 *((uint8_t *)kd->kd_addr + 12),
491 *((uint8_t *)kd->kd_addr + 14));
498 spl_kmem_init_tracking(struct list_head *list, spinlock_t *lock, int size)
502 spin_lock_init(lock);
503 INIT_LIST_HEAD(list);
505 for (i = 0; i < size; i++)
506 INIT_HLIST_HEAD(&kmem_table[i]);
512 spl_kmem_fini_tracking(struct list_head *list, spinlock_t *lock)
518 spin_lock_irqsave(lock, flags);
519 if (!list_empty(list))
520 printk(KERN_WARNING "%-16s %-5s %-16s %s:%s\n", "address",
521 "size", "data", "func", "line");
523 list_for_each_entry(kd, list, kd_list)
524 printk(KERN_WARNING "%p %-5d %-16s %s:%d\n", kd->kd_addr,
525 (int)kd->kd_size, spl_sprintf_addr(kd, str, 17, 8),
526 kd->kd_func, kd->kd_line);
528 spin_unlock_irqrestore(lock, flags);
530 #endif /* DEBUG_KMEM && DEBUG_KMEM_TRACKING */
536 kmem_alloc_used_set(0);
538 #ifdef DEBUG_KMEM_TRACKING
539 spl_kmem_init_tracking(&kmem_list, &kmem_lock, KMEM_TABLE_SIZE);
540 #endif /* DEBUG_KMEM_TRACKING */
541 #endif /* DEBUG_KMEM */
551 * Display all unreclaimed memory addresses, including the
552 * allocation size and the first few bytes of what's located
553 * at that address to aid in debugging. Performance is not
554 * a serious concern here since it is module unload time.
556 if (kmem_alloc_used_read() != 0)
557 printk(KERN_WARNING "kmem leaked %ld/%llu bytes\n",
558 (unsigned long)kmem_alloc_used_read(), kmem_alloc_max);
560 #ifdef DEBUG_KMEM_TRACKING
561 spl_kmem_fini_tracking(&kmem_list, &kmem_lock);
562 #endif /* DEBUG_KMEM_TRACKING */
563 #endif /* DEBUG_KMEM */