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Diffstat (limited to 'module/spl/spl-kmem.c')
| -rw-r--r-- | module/spl/spl-kmem.c | 567 |
1 files changed, 567 insertions, 0 deletions
diff --git a/module/spl/spl-kmem.c b/module/spl/spl-kmem.c new file mode 100644 index 000000000..e0d551041 --- /dev/null +++ b/module/spl/spl-kmem.c @@ -0,0 +1,567 @@ +/* + * Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC. + * Copyright (C) 2007 The Regents of the University of California. + * Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER). + * Written by Brian Behlendorf <[email protected]>. + * UCRL-CODE-235197 + * + * This file is part of the SPL, Solaris Porting Layer. + * For details, see <http://zfsonlinux.org/>. + * + * The SPL is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the + * Free Software Foundation; either version 2 of the License, or (at your + * option) any later version. + * + * The SPL is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + * for more details. + * + * You should have received a copy of the GNU General Public License along + * with the SPL. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <sys/debug.h> +#include <sys/sysmacros.h> +#include <sys/kmem.h> +#include <sys/vmem.h> +#include <linux/mm.h> +#include <linux/ratelimit.h> + +/* + * As a general rule kmem_alloc() allocations should be small, preferably + * just a few pages since they must by physically contiguous. Therefore, a + * rate limited warning will be printed to the console for any kmem_alloc() + * which exceeds a reasonable threshold. + * + * The default warning threshold is set to sixteen pages but capped at 64K to + * accommodate systems using large pages. This value was selected to be small + * enough to ensure the largest allocations are quickly noticed and fixed. + * But large enough to avoid logging any warnings when a allocation size is + * larger than optimal but not a serious concern. Since this value is tunable, + * developers are encouraged to set it lower when testing so any new largish + * allocations are quickly caught. These warnings may be disabled by setting + * the threshold to zero. + */ +/* BEGIN CSTYLED */ +unsigned int spl_kmem_alloc_warn = MIN(16 * PAGE_SIZE, 64 * 1024); +module_param(spl_kmem_alloc_warn, uint, 0644); +MODULE_PARM_DESC(spl_kmem_alloc_warn, + "Warning threshold in bytes for a kmem_alloc()"); +EXPORT_SYMBOL(spl_kmem_alloc_warn); + +/* + * Large kmem_alloc() allocations will fail if they exceed KMALLOC_MAX_SIZE. + * Allocations which are marginally smaller than this limit may succeed but + * should still be avoided due to the expense of locating a contiguous range + * of free pages. Therefore, a maximum kmem size with reasonable safely + * margin of 4x is set. Kmem_alloc() allocations larger than this maximum + * will quickly fail. Vmem_alloc() allocations less than or equal to this + * value will use kmalloc(), but shift to vmalloc() when exceeding this value. + */ +unsigned int spl_kmem_alloc_max = (KMALLOC_MAX_SIZE >> 2); +module_param(spl_kmem_alloc_max, uint, 0644); +MODULE_PARM_DESC(spl_kmem_alloc_max, + "Maximum size in bytes for a kmem_alloc()"); +EXPORT_SYMBOL(spl_kmem_alloc_max); +/* END CSTYLED */ + +int +kmem_debugging(void) +{ + return (0); +} +EXPORT_SYMBOL(kmem_debugging); + +char * +kmem_vasprintf(const char *fmt, va_list ap) +{ + va_list aq; + char *ptr; + + do { + va_copy(aq, ap); + ptr = kvasprintf(kmem_flags_convert(KM_SLEEP), fmt, aq); + va_end(aq); + } while (ptr == NULL); + + return (ptr); +} +EXPORT_SYMBOL(kmem_vasprintf); + +char * +kmem_asprintf(const char *fmt, ...) +{ + va_list ap; + char *ptr; + + do { + va_start(ap, fmt); + ptr = kvasprintf(kmem_flags_convert(KM_SLEEP), fmt, ap); + va_end(ap); + } while (ptr == NULL); + + return (ptr); +} +EXPORT_SYMBOL(kmem_asprintf); + +static char * +__strdup(const char *str, int flags) +{ + char *ptr; + int n; + + n = strlen(str); + ptr = kmalloc(n + 1, kmem_flags_convert(flags)); + if (ptr) + memcpy(ptr, str, n + 1); + + return (ptr); +} + +char * +strdup(const char *str) +{ + return (__strdup(str, KM_SLEEP)); +} +EXPORT_SYMBOL(strdup); + +void +strfree(char *str) +{ + kfree(str); +} +EXPORT_SYMBOL(strfree); + +/* + * Limit the number of large allocation stack traces dumped to not more than + * 5 every 60 seconds to prevent denial-of-service attacks from debug code. + */ +DEFINE_RATELIMIT_STATE(kmem_alloc_ratelimit_state, 60 * HZ, 5); + +/* + * General purpose unified implementation of kmem_alloc(). It is an + * amalgamation of Linux and Illumos allocator design. It should never be + * exported to ensure that code using kmem_alloc()/kmem_zalloc() remains + * relatively portable. Consumers may only access this function through + * wrappers that enforce the common flags to ensure portability. + */ +inline void * +spl_kmem_alloc_impl(size_t size, int flags, int node) +{ + gfp_t lflags = kmem_flags_convert(flags); + int use_vmem = 0; + void *ptr; + + /* + * Log abnormally large allocations and rate limit the console output. + * Allocations larger than spl_kmem_alloc_warn should be performed + * through the vmem_alloc()/vmem_zalloc() interfaces. + */ + if ((spl_kmem_alloc_warn > 0) && (size > spl_kmem_alloc_warn) && + !(flags & KM_VMEM) && __ratelimit(&kmem_alloc_ratelimit_state)) { + printk(KERN_WARNING + "Large kmem_alloc(%lu, 0x%x), please file an issue at:\n" + "https://github.com/zfsonlinux/zfs/issues/new\n", + (unsigned long)size, flags); + dump_stack(); + } + + /* + * Use a loop because kmalloc_node() can fail when GFP_KERNEL is used + * unlike kmem_alloc() with KM_SLEEP on Illumos. + */ + do { + /* + * Calling kmalloc_node() when the size >= spl_kmem_alloc_max + * is unsafe. This must fail for all for kmem_alloc() and + * kmem_zalloc() callers. + * + * For vmem_alloc() and vmem_zalloc() callers it is permissible + * to use __vmalloc(). However, in general use of __vmalloc() + * is strongly discouraged because a global lock must be + * acquired. Contention on this lock can significantly + * impact performance so frequently manipulating the virtual + * address space is strongly discouraged. + */ + if ((size > spl_kmem_alloc_max) || use_vmem) { + if (flags & KM_VMEM) { + ptr = __vmalloc(size, lflags, PAGE_KERNEL); + } else { + return (NULL); + } + } else { + ptr = kmalloc_node(size, lflags, node); + } + + if (likely(ptr) || (flags & KM_NOSLEEP)) + return (ptr); + + /* + * For vmem_alloc() and vmem_zalloc() callers retry immediately + * using __vmalloc() which is unlikely to fail. + */ + if ((flags & KM_VMEM) && (use_vmem == 0)) { + use_vmem = 1; + continue; + } + + if (unlikely(__ratelimit(&kmem_alloc_ratelimit_state))) { + printk(KERN_WARNING + "Possible memory allocation deadlock: " + "size=%lu lflags=0x%x", + (unsigned long)size, lflags); + dump_stack(); + } + + /* + * Use cond_resched() instead of congestion_wait() to avoid + * deadlocking systems where there are no block devices. + */ + cond_resched(); + } while (1); + + return (NULL); +} + +inline void +spl_kmem_free_impl(const void *buf, size_t size) +{ + if (is_vmalloc_addr(buf)) + vfree(buf); + else + kfree(buf); +} + +/* + * Memory allocation and accounting for kmem_* * style allocations. When + * DEBUG_KMEM is enabled the total memory allocated will be tracked and + * any memory leaked will be reported during module unload. + * + * ./configure --enable-debug-kmem + */ +#ifdef DEBUG_KMEM + +/* Shim layer memory accounting */ +#ifdef HAVE_ATOMIC64_T +atomic64_t kmem_alloc_used = ATOMIC64_INIT(0); +unsigned long long kmem_alloc_max = 0; +#else /* HAVE_ATOMIC64_T */ +atomic_t kmem_alloc_used = ATOMIC_INIT(0); +unsigned long long kmem_alloc_max = 0; +#endif /* HAVE_ATOMIC64_T */ + +EXPORT_SYMBOL(kmem_alloc_used); +EXPORT_SYMBOL(kmem_alloc_max); + +inline void * +spl_kmem_alloc_debug(size_t size, int flags, int node) +{ + void *ptr; + + ptr = spl_kmem_alloc_impl(size, flags, node); + if (ptr) { + kmem_alloc_used_add(size); + if (unlikely(kmem_alloc_used_read() > kmem_alloc_max)) + kmem_alloc_max = kmem_alloc_used_read(); + } + + return (ptr); +} + +inline void +spl_kmem_free_debug(const void *ptr, size_t size) +{ + kmem_alloc_used_sub(size); + spl_kmem_free_impl(ptr, size); +} + +/* + * When DEBUG_KMEM_TRACKING is enabled not only will total bytes be tracked + * but also the location of every alloc and free. When the SPL module is + * unloaded a list of all leaked addresses and where they were allocated + * will be dumped to the console. Enabling this feature has a significant + * impact on performance but it makes finding memory leaks straight forward. + * + * Not surprisingly with debugging enabled the xmem_locks are very highly + * contended particularly on xfree(). If we want to run with this detailed + * debugging enabled for anything other than debugging we need to minimize + * the contention by moving to a lock per xmem_table entry model. + * + * ./configure --enable-debug-kmem-tracking + */ +#ifdef DEBUG_KMEM_TRACKING + +#include <linux/hash.h> +#include <linux/ctype.h> + +#define KMEM_HASH_BITS 10 +#define KMEM_TABLE_SIZE (1 << KMEM_HASH_BITS) + +typedef struct kmem_debug { + struct hlist_node kd_hlist; /* Hash node linkage */ + struct list_head kd_list; /* List of all allocations */ + void *kd_addr; /* Allocation pointer */ + size_t kd_size; /* Allocation size */ + const char *kd_func; /* Allocation function */ + int kd_line; /* Allocation line */ +} kmem_debug_t; + +static spinlock_t kmem_lock; +static struct hlist_head kmem_table[KMEM_TABLE_SIZE]; +static struct list_head kmem_list; + +static kmem_debug_t * +kmem_del_init(spinlock_t *lock, struct hlist_head *table, + int bits, const void *addr) +{ + struct hlist_head *head; + struct hlist_node *node; + struct kmem_debug *p; + unsigned long flags; + + spin_lock_irqsave(lock, flags); + + head = &table[hash_ptr((void *)addr, bits)]; + hlist_for_each(node, head) { + p = list_entry(node, struct kmem_debug, kd_hlist); + if (p->kd_addr == addr) { + hlist_del_init(&p->kd_hlist); + list_del_init(&p->kd_list); + spin_unlock_irqrestore(lock, flags); + return (p); + } + } + + spin_unlock_irqrestore(lock, flags); + + return (NULL); +} + +inline void * +spl_kmem_alloc_track(size_t size, int flags, + const char *func, int line, int node) +{ + void *ptr = NULL; + kmem_debug_t *dptr; + unsigned long irq_flags; + + dptr = kmalloc(sizeof (kmem_debug_t), kmem_flags_convert(flags)); + if (dptr == NULL) + return (NULL); + + dptr->kd_func = __strdup(func, flags); + if (dptr->kd_func == NULL) { + kfree(dptr); + return (NULL); + } + + ptr = spl_kmem_alloc_debug(size, flags, node); + if (ptr == NULL) { + kfree(dptr->kd_func); + kfree(dptr); + return (NULL); + } + + INIT_HLIST_NODE(&dptr->kd_hlist); + INIT_LIST_HEAD(&dptr->kd_list); + + dptr->kd_addr = ptr; + dptr->kd_size = size; + dptr->kd_line = line; + + spin_lock_irqsave(&kmem_lock, irq_flags); + hlist_add_head(&dptr->kd_hlist, + &kmem_table[hash_ptr(ptr, KMEM_HASH_BITS)]); + list_add_tail(&dptr->kd_list, &kmem_list); + spin_unlock_irqrestore(&kmem_lock, irq_flags); + + return (ptr); +} + +inline void +spl_kmem_free_track(const void *ptr, size_t size) +{ + kmem_debug_t *dptr; + + /* Ignore NULL pointer since we haven't tracked it at all */ + if (ptr == NULL) + return; + + /* Must exist in hash due to kmem_alloc() */ + dptr = kmem_del_init(&kmem_lock, kmem_table, KMEM_HASH_BITS, ptr); + ASSERT3P(dptr, !=, NULL); + ASSERT3S(dptr->kd_size, ==, size); + + kfree(dptr->kd_func); + kfree(dptr); + + spl_kmem_free_debug(ptr, size); +} +#endif /* DEBUG_KMEM_TRACKING */ +#endif /* DEBUG_KMEM */ + +/* + * Public kmem_alloc(), kmem_zalloc() and kmem_free() interfaces. + */ +void * +spl_kmem_alloc(size_t size, int flags, const char *func, int line) +{ + ASSERT0(flags & ~KM_PUBLIC_MASK); + +#if !defined(DEBUG_KMEM) + return (spl_kmem_alloc_impl(size, flags, NUMA_NO_NODE)); +#elif !defined(DEBUG_KMEM_TRACKING) + return (spl_kmem_alloc_debug(size, flags, NUMA_NO_NODE)); +#else + return (spl_kmem_alloc_track(size, flags, func, line, NUMA_NO_NODE)); +#endif +} +EXPORT_SYMBOL(spl_kmem_alloc); + +void * +spl_kmem_zalloc(size_t size, int flags, const char *func, int line) +{ + ASSERT0(flags & ~KM_PUBLIC_MASK); + + flags |= KM_ZERO; + +#if !defined(DEBUG_KMEM) + return (spl_kmem_alloc_impl(size, flags, NUMA_NO_NODE)); +#elif !defined(DEBUG_KMEM_TRACKING) + return (spl_kmem_alloc_debug(size, flags, NUMA_NO_NODE)); +#else + return (spl_kmem_alloc_track(size, flags, func, line, NUMA_NO_NODE)); +#endif +} +EXPORT_SYMBOL(spl_kmem_zalloc); + +void +spl_kmem_free(const void *buf, size_t size) +{ +#if !defined(DEBUG_KMEM) + return (spl_kmem_free_impl(buf, size)); +#elif !defined(DEBUG_KMEM_TRACKING) + return (spl_kmem_free_debug(buf, size)); +#else + return (spl_kmem_free_track(buf, size)); +#endif +} +EXPORT_SYMBOL(spl_kmem_free); + +#if defined(DEBUG_KMEM) && defined(DEBUG_KMEM_TRACKING) +static char * +spl_sprintf_addr(kmem_debug_t *kd, char *str, int len, int min) +{ + int size = ((len - 1) < kd->kd_size) ? (len - 1) : kd->kd_size; + int i, flag = 1; + + ASSERT(str != NULL && len >= 17); + memset(str, 0, len); + + /* + * Check for a fully printable string, and while we are at + * it place the printable characters in the passed buffer. + */ + for (i = 0; i < size; i++) { + str[i] = ((char *)(kd->kd_addr))[i]; + if (isprint(str[i])) { + continue; + } else { + /* + * Minimum number of printable characters found + * to make it worthwhile to print this as ascii. + */ + if (i > min) + break; + + flag = 0; + break; + } + } + + if (!flag) { + sprintf(str, "%02x%02x%02x%02x%02x%02x%02x%02x", + *((uint8_t *)kd->kd_addr), + *((uint8_t *)kd->kd_addr + 2), + *((uint8_t *)kd->kd_addr + 4), + *((uint8_t *)kd->kd_addr + 6), + *((uint8_t *)kd->kd_addr + 8), + *((uint8_t *)kd->kd_addr + 10), + *((uint8_t *)kd->kd_addr + 12), + *((uint8_t *)kd->kd_addr + 14)); + } + + return (str); +} + +static int +spl_kmem_init_tracking(struct list_head *list, spinlock_t *lock, int size) +{ + int i; + + spin_lock_init(lock); + INIT_LIST_HEAD(list); + + for (i = 0; i < size; i++) + INIT_HLIST_HEAD(&kmem_table[i]); + + return (0); +} + +static void +spl_kmem_fini_tracking(struct list_head *list, spinlock_t *lock) +{ + unsigned long flags; + kmem_debug_t *kd; + char str[17]; + + spin_lock_irqsave(lock, flags); + if (!list_empty(list)) + printk(KERN_WARNING "%-16s %-5s %-16s %s:%s\n", "address", + "size", "data", "func", "line"); + + list_for_each_entry(kd, list, kd_list) { + printk(KERN_WARNING "%p %-5d %-16s %s:%d\n", kd->kd_addr, + (int)kd->kd_size, spl_sprintf_addr(kd, str, 17, 8), + kd->kd_func, kd->kd_line); + } + + spin_unlock_irqrestore(lock, flags); +} +#endif /* DEBUG_KMEM && DEBUG_KMEM_TRACKING */ + +int +spl_kmem_init(void) +{ +#ifdef DEBUG_KMEM + kmem_alloc_used_set(0); + +#ifdef DEBUG_KMEM_TRACKING + spl_kmem_init_tracking(&kmem_list, &kmem_lock, KMEM_TABLE_SIZE); +#endif /* DEBUG_KMEM_TRACKING */ +#endif /* DEBUG_KMEM */ + + return (0); +} + +void +spl_kmem_fini(void) +{ +#ifdef DEBUG_KMEM + /* + * Display all unreclaimed memory addresses, including the + * allocation size and the first few bytes of what's located + * at that address to aid in debugging. Performance is not + * a serious concern here since it is module unload time. + */ + if (kmem_alloc_used_read() != 0) + printk(KERN_WARNING "kmem leaked %ld/%llu bytes\n", + (unsigned long)kmem_alloc_used_read(), kmem_alloc_max); + +#ifdef DEBUG_KMEM_TRACKING + spl_kmem_fini_tracking(&kmem_list, &kmem_lock); +#endif /* DEBUG_KMEM_TRACKING */ +#endif /* DEBUG_KMEM */ +} |