| /* |
| * SLUB: A slab allocator that limits cache line use instead of queuing |
| * objects in per cpu and per node lists. |
| * |
| * The allocator synchronizes using per slab locks and only |
| * uses a centralized lock to manage a pool of partial slabs. |
| * |
| * (C) 2007 SGI, Christoph Lameter <clameter@sgi.com> |
| */ |
| |
| #include <linux/mm.h> |
| #include <linux/module.h> |
| #include <linux/bit_spinlock.h> |
| #include <linux/interrupt.h> |
| #include <linux/bitops.h> |
| #include <linux/slab.h> |
| #include <linux/seq_file.h> |
| #include <linux/cpu.h> |
| #include <linux/cpuset.h> |
| #include <linux/mempolicy.h> |
| #include <linux/ctype.h> |
| #include <linux/kallsyms.h> |
| |
| /* |
| * Lock order: |
| * 1. slab_lock(page) |
| * 2. slab->list_lock |
| * |
| * The slab_lock protects operations on the object of a particular |
| * slab and its metadata in the page struct. If the slab lock |
| * has been taken then no allocations nor frees can be performed |
| * on the objects in the slab nor can the slab be added or removed |
| * from the partial or full lists since this would mean modifying |
| * the page_struct of the slab. |
| * |
| * The list_lock protects the partial and full list on each node and |
| * the partial slab counter. If taken then no new slabs may be added or |
| * removed from the lists nor make the number of partial slabs be modified. |
| * (Note that the total number of slabs is an atomic value that may be |
| * modified without taking the list lock). |
| * |
| * The list_lock is a centralized lock and thus we avoid taking it as |
| * much as possible. As long as SLUB does not have to handle partial |
| * slabs, operations can continue without any centralized lock. F.e. |
| * allocating a long series of objects that fill up slabs does not require |
| * the list lock. |
| * |
| * The lock order is sometimes inverted when we are trying to get a slab |
| * off a list. We take the list_lock and then look for a page on the list |
| * to use. While we do that objects in the slabs may be freed. We can |
| * only operate on the slab if we have also taken the slab_lock. So we use |
| * a slab_trylock() on the slab. If trylock was successful then no frees |
| * can occur anymore and we can use the slab for allocations etc. If the |
| * slab_trylock() does not succeed then frees are in progress in the slab and |
| * we must stay away from it for a while since we may cause a bouncing |
| * cacheline if we try to acquire the lock. So go onto the next slab. |
| * If all pages are busy then we may allocate a new slab instead of reusing |
| * a partial slab. A new slab has noone operating on it and thus there is |
| * no danger of cacheline contention. |
| * |
| * Interrupts are disabled during allocation and deallocation in order to |
| * make the slab allocator safe to use in the context of an irq. In addition |
| * interrupts are disabled to ensure that the processor does not change |
| * while handling per_cpu slabs, due to kernel preemption. |
| * |
| * SLUB assigns one slab for allocation to each processor. |
| * Allocations only occur from these slabs called cpu slabs. |
| * |
| * Slabs with free elements are kept on a partial list and during regular |
| * operations no list for full slabs is used. If an object in a full slab is |
| * freed then the slab will show up again on the partial lists. |
| * We track full slabs for debugging purposes though because otherwise we |
| * cannot scan all objects. |
| * |
| * Slabs are freed when they become empty. Teardown and setup is |
| * minimal so we rely on the page allocators per cpu caches for |
| * fast frees and allocs. |
| * |
| * Overloading of page flags that are otherwise used for LRU management. |
| * |
| * PageActive The slab is frozen and exempt from list processing. |
| * This means that the slab is dedicated to a purpose |
| * such as satisfying allocations for a specific |
| * processor. Objects may be freed in the slab while |
| * it is frozen but slab_free will then skip the usual |
| * list operations. It is up to the processor holding |
| * the slab to integrate the slab into the slab lists |
| * when the slab is no longer needed. |
| * |
| * One use of this flag is to mark slabs that are |
| * used for allocations. Then such a slab becomes a cpu |
| * slab. The cpu slab may be equipped with an additional |
| * lockless_freelist that allows lockless access to |
| * free objects in addition to the regular freelist |
| * that requires the slab lock. |
| * |
| * PageError Slab requires special handling due to debug |
| * options set. This moves slab handling out of |
| * the fast path and disables lockless freelists. |
| */ |
| |
| #define FROZEN (1 << PG_active) |
| |
| #ifdef CONFIG_SLUB_DEBUG |
| #define SLABDEBUG (1 << PG_error) |
| #else |
| #define SLABDEBUG 0 |
| #endif |
| |
| static inline int SlabFrozen(struct page *page) |
| { |
| return page->flags & FROZEN; |
| } |
| |
| static inline void SetSlabFrozen(struct page *page) |
| { |
| page->flags |= FROZEN; |
| } |
| |
| static inline void ClearSlabFrozen(struct page *page) |
| { |
| page->flags &= ~FROZEN; |
| } |
| |
| static inline int SlabDebug(struct page *page) |
| { |
| return page->flags & SLABDEBUG; |
| } |
| |
| static inline void SetSlabDebug(struct page *page) |
| { |
| page->flags |= SLABDEBUG; |
| } |
| |
| static inline void ClearSlabDebug(struct page *page) |
| { |
| page->flags &= ~SLABDEBUG; |
| } |
| |
| /* |
| * Issues still to be resolved: |
| * |
| * - The per cpu array is updated for each new slab and and is a remote |
| * cacheline for most nodes. This could become a bouncing cacheline given |
| * enough frequent updates. There are 16 pointers in a cacheline, so at |
| * max 16 cpus could compete for the cacheline which may be okay. |
| * |
| * - Support PAGE_ALLOC_DEBUG. Should be easy to do. |
| * |
| * - Variable sizing of the per node arrays |
| */ |
| |
| /* Enable to test recovery from slab corruption on boot */ |
| #undef SLUB_RESILIENCY_TEST |
| |
| #if PAGE_SHIFT <= 12 |
| |
| /* |
| * Small page size. Make sure that we do not fragment memory |
| */ |
| #define DEFAULT_MAX_ORDER 1 |
| #define DEFAULT_MIN_OBJECTS 4 |
| |
| #else |
| |
| /* |
| * Large page machines are customarily able to handle larger |
| * page orders. |
| */ |
| #define DEFAULT_MAX_ORDER 2 |
| #define DEFAULT_MIN_OBJECTS 8 |
| |
| #endif |
| |
| /* |
| * Mininum number of partial slabs. These will be left on the partial |
| * lists even if they are empty. kmem_cache_shrink may reclaim them. |
| */ |
| #define MIN_PARTIAL 2 |
| |
| /* |
| * Maximum number of desirable partial slabs. |
| * The existence of more partial slabs makes kmem_cache_shrink |
| * sort the partial list by the number of objects in the. |
| */ |
| #define MAX_PARTIAL 10 |
| |
| #define DEBUG_DEFAULT_FLAGS (SLAB_DEBUG_FREE | SLAB_RED_ZONE | \ |
| SLAB_POISON | SLAB_STORE_USER) |
| |
| /* |
| * Set of flags that will prevent slab merging |
| */ |
| #define SLUB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \ |
| SLAB_TRACE | SLAB_DESTROY_BY_RCU) |
| |
| #define SLUB_MERGE_SAME (SLAB_DEBUG_FREE | SLAB_RECLAIM_ACCOUNT | \ |
| SLAB_CACHE_DMA) |
| |
| #ifndef ARCH_KMALLOC_MINALIGN |
| #define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long) |
| #endif |
| |
| #ifndef ARCH_SLAB_MINALIGN |
| #define ARCH_SLAB_MINALIGN __alignof__(unsigned long long) |
| #endif |
| |
| /* |
| * The page->inuse field is 16 bit thus we have this limitation |
| */ |
| #define MAX_OBJECTS_PER_SLAB 65535 |
| |
| /* Internal SLUB flags */ |
| #define __OBJECT_POISON 0x80000000 /* Poison object */ |
| |
| /* Not all arches define cache_line_size */ |
| #ifndef cache_line_size |
| #define cache_line_size() L1_CACHE_BYTES |
| #endif |
| |
| static int kmem_size = sizeof(struct kmem_cache); |
| |
| #ifdef CONFIG_SMP |
| static struct notifier_block slab_notifier; |
| #endif |
| |
| static enum { |
| DOWN, /* No slab functionality available */ |
| PARTIAL, /* kmem_cache_open() works but kmalloc does not */ |
| UP, /* Everything works but does not show up in sysfs */ |
| SYSFS /* Sysfs up */ |
| } slab_state = DOWN; |
| |
| /* A list of all slab caches on the system */ |
| static DECLARE_RWSEM(slub_lock); |
| LIST_HEAD(slab_caches); |
| |
| /* |
| * Tracking user of a slab. |
| */ |
| struct track { |
| void *addr; /* Called from address */ |
| int cpu; /* Was running on cpu */ |
| int pid; /* Pid context */ |
| unsigned long when; /* When did the operation occur */ |
| }; |
| |
| enum track_item { TRACK_ALLOC, TRACK_FREE }; |
| |
| #if defined(CONFIG_SYSFS) && defined(CONFIG_SLUB_DEBUG) |
| static int sysfs_slab_add(struct kmem_cache *); |
| static int sysfs_slab_alias(struct kmem_cache *, const char *); |
| static void sysfs_slab_remove(struct kmem_cache *); |
| #else |
| static int sysfs_slab_add(struct kmem_cache *s) { return 0; } |
| static int sysfs_slab_alias(struct kmem_cache *s, const char *p) { return 0; } |
| static void sysfs_slab_remove(struct kmem_cache *s) {} |
| #endif |
| |
| /******************************************************************** |
| * Core slab cache functions |
| *******************************************************************/ |
| |
| int slab_is_available(void) |
| { |
| return slab_state >= UP; |
| } |
| |
| static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node) |
| { |
| #ifdef CONFIG_NUMA |
| return s->node[node]; |
| #else |
| return &s->local_node; |
| #endif |
| } |
| |
| static inline int check_valid_pointer(struct kmem_cache *s, |
| struct page *page, const void *object) |
| { |
| void *base; |
| |
| if (!object) |
| return 1; |
| |
| base = page_address(page); |
| if (object < base || object >= base + s->objects * s->size || |
| (object - base) % s->size) { |
| return 0; |
| } |
| |
| return 1; |
| } |
| |
| /* |
| * Slow version of get and set free pointer. |
| * |
| * This version requires touching the cache lines of kmem_cache which |
| * we avoid to do in the fast alloc free paths. There we obtain the offset |
| * from the page struct. |
| */ |
| static inline void *get_freepointer(struct kmem_cache *s, void *object) |
| { |
| return *(void **)(object + s->offset); |
| } |
| |
| static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp) |
| { |
| *(void **)(object + s->offset) = fp; |
| } |
| |
| /* Loop over all objects in a slab */ |
| #define for_each_object(__p, __s, __addr) \ |
| for (__p = (__addr); __p < (__addr) + (__s)->objects * (__s)->size;\ |
| __p += (__s)->size) |
| |
| /* Scan freelist */ |
| #define for_each_free_object(__p, __s, __free) \ |
| for (__p = (__free); __p; __p = get_freepointer((__s), __p)) |
| |
| /* Determine object index from a given position */ |
| static inline int slab_index(void *p, struct kmem_cache *s, void *addr) |
| { |
| return (p - addr) / s->size; |
| } |
| |
| #ifdef CONFIG_SLUB_DEBUG |
| /* |
| * Debug settings: |
| */ |
| #ifdef CONFIG_SLUB_DEBUG_ON |
| static int slub_debug = DEBUG_DEFAULT_FLAGS; |
| #else |
| static int slub_debug; |
| #endif |
| |
| static char *slub_debug_slabs; |
| |
| /* |
| * Object debugging |
| */ |
| static void print_section(char *text, u8 *addr, unsigned int length) |
| { |
| int i, offset; |
| int newline = 1; |
| char ascii[17]; |
| |
| ascii[16] = 0; |
| |
| for (i = 0; i < length; i++) { |
| if (newline) { |
| printk(KERN_ERR "%8s 0x%p: ", text, addr + i); |
| newline = 0; |
| } |
| printk(" %02x", addr[i]); |
| offset = i % 16; |
| ascii[offset] = isgraph(addr[i]) ? addr[i] : '.'; |
| if (offset == 15) { |
| printk(" %s\n",ascii); |
| newline = 1; |
| } |
| } |
| if (!newline) { |
| i %= 16; |
| while (i < 16) { |
| printk(" "); |
| ascii[i] = ' '; |
| i++; |
| } |
| printk(" %s\n", ascii); |
| } |
| } |
| |
| static struct track *get_track(struct kmem_cache *s, void *object, |
| enum track_item alloc) |
| { |
| struct track *p; |
| |
| if (s->offset) |
| p = object + s->offset + sizeof(void *); |
| else |
| p = object + s->inuse; |
| |
| return p + alloc; |
| } |
| |
| static void set_track(struct kmem_cache *s, void *object, |
| enum track_item alloc, void *addr) |
| { |
| struct track *p; |
| |
| if (s->offset) |
| p = object + s->offset + sizeof(void *); |
| else |
| p = object + s->inuse; |
| |
| p += alloc; |
| if (addr) { |
| p->addr = addr; |
| p->cpu = smp_processor_id(); |
| p->pid = current ? current->pid : -1; |
| p->when = jiffies; |
| } else |
| memset(p, 0, sizeof(struct track)); |
| } |
| |
| static void init_tracking(struct kmem_cache *s, void *object) |
| { |
| if (!(s->flags & SLAB_STORE_USER)) |
| return; |
| |
| set_track(s, object, TRACK_FREE, NULL); |
| set_track(s, object, TRACK_ALLOC, NULL); |
| } |
| |
| static void print_track(const char *s, struct track *t) |
| { |
| if (!t->addr) |
| return; |
| |
| printk(KERN_ERR "INFO: %s in ", s); |
| __print_symbol("%s", (unsigned long)t->addr); |
| printk(" age=%lu cpu=%u pid=%d\n", jiffies - t->when, t->cpu, t->pid); |
| } |
| |
| static void print_tracking(struct kmem_cache *s, void *object) |
| { |
| if (!(s->flags & SLAB_STORE_USER)) |
| return; |
| |
| print_track("Allocated", get_track(s, object, TRACK_ALLOC)); |
| print_track("Freed", get_track(s, object, TRACK_FREE)); |
| } |
| |
| static void print_page_info(struct page *page) |
| { |
| printk(KERN_ERR "INFO: Slab 0x%p used=%u fp=0x%p flags=0x%04lx\n", |
| page, page->inuse, page->freelist, page->flags); |
| |
| } |
| |
| static void slab_bug(struct kmem_cache *s, char *fmt, ...) |
| { |
| va_list args; |
| char buf[100]; |
| |
| va_start(args, fmt); |
| vsnprintf(buf, sizeof(buf), fmt, args); |
| va_end(args); |
| printk(KERN_ERR "========================================" |
| "=====================================\n"); |
| printk(KERN_ERR "BUG %s: %s\n", s->name, buf); |
| printk(KERN_ERR "----------------------------------------" |
| "-------------------------------------\n\n"); |
| } |
| |
| static void slab_fix(struct kmem_cache *s, char *fmt, ...) |
| { |
| va_list args; |
| char buf[100]; |
| |
| va_start(args, fmt); |
| vsnprintf(buf, sizeof(buf), fmt, args); |
| va_end(args); |
| printk(KERN_ERR "FIX %s: %s\n", s->name, buf); |
| } |
| |
| static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p) |
| { |
| unsigned int off; /* Offset of last byte */ |
| u8 *addr = page_address(page); |
| |
| print_tracking(s, p); |
| |
| print_page_info(page); |
| |
| printk(KERN_ERR "INFO: Object 0x%p @offset=%tu fp=0x%p\n\n", |
| p, p - addr, get_freepointer(s, p)); |
| |
| if (p > addr + 16) |
| print_section("Bytes b4", p - 16, 16); |
| |
| print_section("Object", p, min(s->objsize, 128)); |
| |
| if (s->flags & SLAB_RED_ZONE) |
| print_section("Redzone", p + s->objsize, |
| s->inuse - s->objsize); |
| |
| if (s->offset) |
| off = s->offset + sizeof(void *); |
| else |
| off = s->inuse; |
| |
| if (s->flags & SLAB_STORE_USER) |
| off += 2 * sizeof(struct track); |
| |
| if (off != s->size) |
| /* Beginning of the filler is the free pointer */ |
| print_section("Padding", p + off, s->size - off); |
| |
| dump_stack(); |
| } |
| |
| static void object_err(struct kmem_cache *s, struct page *page, |
| u8 *object, char *reason) |
| { |
| slab_bug(s, reason); |
| print_trailer(s, page, object); |
| } |
| |
| static void slab_err(struct kmem_cache *s, struct page *page, char *fmt, ...) |
| { |
| va_list args; |
| char buf[100]; |
| |
| va_start(args, fmt); |
| vsnprintf(buf, sizeof(buf), fmt, args); |
| va_end(args); |
| slab_bug(s, fmt); |
| print_page_info(page); |
| dump_stack(); |
| } |
| |
| static void init_object(struct kmem_cache *s, void *object, int active) |
| { |
| u8 *p = object; |
| |
| if (s->flags & __OBJECT_POISON) { |
| memset(p, POISON_FREE, s->objsize - 1); |
| p[s->objsize -1] = POISON_END; |
| } |
| |
| if (s->flags & SLAB_RED_ZONE) |
| memset(p + s->objsize, |
| active ? SLUB_RED_ACTIVE : SLUB_RED_INACTIVE, |
| s->inuse - s->objsize); |
| } |
| |
| static u8 *check_bytes(u8 *start, unsigned int value, unsigned int bytes) |
| { |
| while (bytes) { |
| if (*start != (u8)value) |
| return start; |
| start++; |
| bytes--; |
| } |
| return NULL; |
| } |
| |
| static void restore_bytes(struct kmem_cache *s, char *message, u8 data, |
| void *from, void *to) |
| { |
| slab_fix(s, "Restoring 0x%p-0x%p=0x%x\n", from, to - 1, data); |
| memset(from, data, to - from); |
| } |
| |
| static int check_bytes_and_report(struct kmem_cache *s, struct page *page, |
| u8 *object, char *what, |
| u8* start, unsigned int value, unsigned int bytes) |
| { |
| u8 *fault; |
| u8 *end; |
| |
| fault = check_bytes(start, value, bytes); |
| if (!fault) |
| return 1; |
| |
| end = start + bytes; |
| while (end > fault && end[-1] == value) |
| end--; |
| |
| slab_bug(s, "%s overwritten", what); |
| printk(KERN_ERR "INFO: 0x%p-0x%p. First byte 0x%x instead of 0x%x\n", |
| fault, end - 1, fault[0], value); |
| print_trailer(s, page, object); |
| |
| restore_bytes(s, what, value, fault, end); |
| return 0; |
| } |
| |
| /* |
| * Object layout: |
| * |
| * object address |
| * Bytes of the object to be managed. |
| * If the freepointer may overlay the object then the free |
| * pointer is the first word of the object. |
| * |
| * Poisoning uses 0x6b (POISON_FREE) and the last byte is |
| * 0xa5 (POISON_END) |
| * |
| * object + s->objsize |
| * Padding to reach word boundary. This is also used for Redzoning. |
| * Padding is extended by another word if Redzoning is enabled and |
| * objsize == inuse. |
| * |
| * We fill with 0xbb (RED_INACTIVE) for inactive objects and with |
| * 0xcc (RED_ACTIVE) for objects in use. |
| * |
| * object + s->inuse |
| * Meta data starts here. |
| * |
| * A. Free pointer (if we cannot overwrite object on free) |
| * B. Tracking data for SLAB_STORE_USER |
| * C. Padding to reach required alignment boundary or at mininum |
| * one word if debuggin is on to be able to detect writes |
| * before the word boundary. |
| * |
| * Padding is done using 0x5a (POISON_INUSE) |
| * |
| * object + s->size |
| * Nothing is used beyond s->size. |
| * |
| * If slabcaches are merged then the objsize and inuse boundaries are mostly |
| * ignored. And therefore no slab options that rely on these boundaries |
| * may be used with merged slabcaches. |
| */ |
| |
| static int check_pad_bytes(struct kmem_cache *s, struct page *page, u8 *p) |
| { |
| unsigned long off = s->inuse; /* The end of info */ |
| |
| if (s->offset) |
| /* Freepointer is placed after the object. */ |
| off += sizeof(void *); |
| |
| if (s->flags & SLAB_STORE_USER) |
| /* We also have user information there */ |
| off += 2 * sizeof(struct track); |
| |
| if (s->size == off) |
| return 1; |
| |
| return check_bytes_and_report(s, page, p, "Object padding", |
| p + off, POISON_INUSE, s->size - off); |
| } |
| |
| static int slab_pad_check(struct kmem_cache *s, struct page *page) |
| { |
| u8 *start; |
| u8 *fault; |
| u8 *end; |
| int length; |
| int remainder; |
| |
| if (!(s->flags & SLAB_POISON)) |
| return 1; |
| |
| start = page_address(page); |
| end = start + (PAGE_SIZE << s->order); |
| length = s->objects * s->size; |
| remainder = end - (start + length); |
| if (!remainder) |
| return 1; |
| |
| fault = check_bytes(start + length, POISON_INUSE, remainder); |
| if (!fault) |
| return 1; |
| while (end > fault && end[-1] == POISON_INUSE) |
| end--; |
| |
| slab_err(s, page, "Padding overwritten. 0x%p-0x%p", fault, end - 1); |
| print_section("Padding", start, length); |
| |
| restore_bytes(s, "slab padding", POISON_INUSE, start, end); |
| return 0; |
| } |
| |
| static int check_object(struct kmem_cache *s, struct page *page, |
| void *object, int active) |
| { |
| u8 *p = object; |
| u8 *endobject = object + s->objsize; |
| |
| if (s->flags & SLAB_RED_ZONE) { |
| unsigned int red = |
| active ? SLUB_RED_ACTIVE : SLUB_RED_INACTIVE; |
| |
| if (!check_bytes_and_report(s, page, object, "Redzone", |
| endobject, red, s->inuse - s->objsize)) |
| return 0; |
| } else { |
| if ((s->flags & SLAB_POISON) && s->objsize < s->inuse) |
| check_bytes_and_report(s, page, p, "Alignment padding", endobject, |
| POISON_INUSE, s->inuse - s->objsize); |
| } |
| |
| if (s->flags & SLAB_POISON) { |
| if (!active && (s->flags & __OBJECT_POISON) && |
| (!check_bytes_and_report(s, page, p, "Poison", p, |
| POISON_FREE, s->objsize - 1) || |
| !check_bytes_and_report(s, page, p, "Poison", |
| p + s->objsize -1, POISON_END, 1))) |
| return 0; |
| /* |
| * check_pad_bytes cleans up on its own. |
| */ |
| check_pad_bytes(s, page, p); |
| } |
| |
| if (!s->offset && active) |
| /* |
| * Object and freepointer overlap. Cannot check |
| * freepointer while object is allocated. |
| */ |
| return 1; |
| |
| /* Check free pointer validity */ |
| if (!check_valid_pointer(s, page, get_freepointer(s, p))) { |
| object_err(s, page, p, "Freepointer corrupt"); |
| /* |
| * No choice but to zap it and thus loose the remainder |
| * of the free objects in this slab. May cause |
| * another error because the object count is now wrong. |
| */ |
| set_freepointer(s, p, NULL); |
| return 0; |
| } |
| return 1; |
| } |
| |
| static int check_slab(struct kmem_cache *s, struct page *page) |
| { |
| VM_BUG_ON(!irqs_disabled()); |
| |
| if (!PageSlab(page)) { |
| slab_err(s, page, "Not a valid slab page"); |
| return 0; |
| } |
| if (page->offset * sizeof(void *) != s->offset) { |
| slab_err(s, page, "Corrupted offset %lu", |
| (unsigned long)(page->offset * sizeof(void *))); |
| return 0; |
| } |
| if (page->inuse > s->objects) { |
| slab_err(s, page, "inuse %u > max %u", |
| s->name, page->inuse, s->objects); |
| return 0; |
| } |
| /* Slab_pad_check fixes things up after itself */ |
| slab_pad_check(s, page); |
| return 1; |
| } |
| |
| /* |
| * Determine if a certain object on a page is on the freelist. Must hold the |
| * slab lock to guarantee that the chains are in a consistent state. |
| */ |
| static int on_freelist(struct kmem_cache *s, struct page *page, void *search) |
| { |
| int nr = 0; |
| void *fp = page->freelist; |
| void *object = NULL; |
| |
| while (fp && nr <= s->objects) { |
| if (fp == search) |
| return 1; |
| if (!check_valid_pointer(s, page, fp)) { |
| if (object) { |
| object_err(s, page, object, |
| "Freechain corrupt"); |
| set_freepointer(s, object, NULL); |
| break; |
| } else { |
| slab_err(s, page, "Freepointer corrupt"); |
| page->freelist = NULL; |
| page->inuse = s->objects; |
| slab_fix(s, "Freelist cleared"); |
| return 0; |
| } |
| break; |
| } |
| object = fp; |
| fp = get_freepointer(s, object); |
| nr++; |
| } |
| |
| if (page->inuse != s->objects - nr) { |
| slab_err(s, page, "Wrong object count. Counter is %d but " |
| "counted were %d", page->inuse, s->objects - nr); |
| page->inuse = s->objects - nr; |
| slab_fix(s, "Object count adjusted."); |
| } |
| return search == NULL; |
| } |
| |
| static void trace(struct kmem_cache *s, struct page *page, void *object, int alloc) |
| { |
| if (s->flags & SLAB_TRACE) { |
| printk(KERN_INFO "TRACE %s %s 0x%p inuse=%d fp=0x%p\n", |
| s->name, |
| alloc ? "alloc" : "free", |
| object, page->inuse, |
| page->freelist); |
| |
| if (!alloc) |
| print_section("Object", (void *)object, s->objsize); |
| |
| dump_stack(); |
| } |
| } |
| |
| /* |
| * Tracking of fully allocated slabs for debugging purposes. |
| */ |
| static void add_full(struct kmem_cache_node *n, struct page *page) |
| { |
| spin_lock(&n->list_lock); |
| list_add(&page->lru, &n->full); |
| spin_unlock(&n->list_lock); |
| } |
| |
| static void remove_full(struct kmem_cache *s, struct page *page) |
| { |
| struct kmem_cache_node *n; |
| |
| if (!(s->flags & SLAB_STORE_USER)) |
| return; |
| |
| n = get_node(s, page_to_nid(page)); |
| |
| spin_lock(&n->list_lock); |
| list_del(&page->lru); |
| spin_unlock(&n->list_lock); |
| } |
| |
| static void setup_object_debug(struct kmem_cache *s, struct page *page, |
| void *object) |
| { |
| if (!(s->flags & (SLAB_STORE_USER|SLAB_RED_ZONE|__OBJECT_POISON))) |
| return; |
| |
| init_object(s, object, 0); |
| init_tracking(s, object); |
| } |
| |
| static int alloc_debug_processing(struct kmem_cache *s, struct page *page, |
| void *object, void *addr) |
| { |
| if (!check_slab(s, page)) |
| goto bad; |
| |
| if (object && !on_freelist(s, page, object)) { |
| object_err(s, page, object, "Object already allocated"); |
| goto bad; |
| } |
| |
| if (!check_valid_pointer(s, page, object)) { |
| object_err(s, page, object, "Freelist Pointer check fails"); |
| goto bad; |
| } |
| |
| if (object && !check_object(s, page, object, 0)) |
| goto bad; |
| |
| /* Success perform special debug activities for allocs */ |
| if (s->flags & SLAB_STORE_USER) |
| set_track(s, object, TRACK_ALLOC, addr); |
| trace(s, page, object, 1); |
| init_object(s, object, 1); |
| return 1; |
| |
| bad: |
| if (PageSlab(page)) { |
| /* |
| * If this is a slab page then lets do the best we can |
| * to avoid issues in the future. Marking all objects |
| * as used avoids touching the remaining objects. |
| */ |
| slab_fix(s, "Marking all objects used"); |
| page->inuse = s->objects; |
| page->freelist = NULL; |
| /* Fix up fields that may be corrupted */ |
| page->offset = s->offset / sizeof(void *); |
| } |
| return 0; |
| } |
| |
| static int free_debug_processing(struct kmem_cache *s, struct page *page, |
| void *object, void *addr) |
| { |
| if (!check_slab(s, page)) |
| goto fail; |
| |
| if (!check_valid_pointer(s, page, object)) { |
| slab_err(s, page, "Invalid object pointer 0x%p", object); |
| goto fail; |
| } |
| |
| if (on_freelist(s, page, object)) { |
| object_err(s, page, object, "Object already free"); |
| goto fail; |
| } |
| |
| if (!check_object(s, page, object, 1)) |
| return 0; |
| |
| if (unlikely(s != page->slab)) { |
| if (!PageSlab(page)) |
| slab_err(s, page, "Attempt to free object(0x%p) " |
| "outside of slab", object); |
| else |
| if (!page->slab) { |
| printk(KERN_ERR |
| "SLUB <none>: no slab for object 0x%p.\n", |
| object); |
| dump_stack(); |
| } |
| else |
| object_err(s, page, object, |
| "page slab pointer corrupt."); |
| goto fail; |
| } |
| |
| /* Special debug activities for freeing objects */ |
| if (!SlabFrozen(page) && !page->freelist) |
| remove_full(s, page); |
| if (s->flags & SLAB_STORE_USER) |
| set_track(s, object, TRACK_FREE, addr); |
| trace(s, page, object, 0); |
| init_object(s, object, 0); |
| return 1; |
| |
| fail: |
| slab_fix(s, "Object at 0x%p not freed", object); |
| return 0; |
| } |
| |
| static int __init setup_slub_debug(char *str) |
| { |
| slub_debug = DEBUG_DEFAULT_FLAGS; |
| if (*str++ != '=' || !*str) |
| /* |
| * No options specified. Switch on full debugging. |
| */ |
| goto out; |
| |
| if (*str == ',') |
| /* |
| * No options but restriction on slabs. This means full |
| * debugging for slabs matching a pattern. |
| */ |
| goto check_slabs; |
| |
| slub_debug = 0; |
| if (*str == '-') |
| /* |
| * Switch off all debugging measures. |
| */ |
| goto out; |
| |
| /* |
| * Determine which debug features should be switched on |
| */ |
| for ( ;*str && *str != ','; str++) { |
| switch (tolower(*str)) { |
| case 'f': |
| slub_debug |= SLAB_DEBUG_FREE; |
| break; |
| case 'z': |
| slub_debug |= SLAB_RED_ZONE; |
| break; |
| case 'p': |
| slub_debug |= SLAB_POISON; |
| break; |
| case 'u': |
| slub_debug |= SLAB_STORE_USER; |
| break; |
| case 't': |
| slub_debug |= SLAB_TRACE; |
| break; |
| default: |
| printk(KERN_ERR "slub_debug option '%c' " |
| "unknown. skipped\n",*str); |
| } |
| } |
| |
| check_slabs: |
| if (*str == ',') |
| slub_debug_slabs = str + 1; |
| out: |
| return 1; |
| } |
| |
| __setup("slub_debug", setup_slub_debug); |
| |
| static void kmem_cache_open_debug_check(struct kmem_cache *s) |
| { |
| /* |
| * The page->offset field is only 16 bit wide. This is an offset |
| * in units of words from the beginning of an object. If the slab |
| * size is bigger then we cannot move the free pointer behind the |
| * object anymore. |
| * |
| * On 32 bit platforms the limit is 256k. On 64bit platforms |
| * the limit is 512k. |
| * |
| * Debugging or ctor may create a need to move the free |
| * pointer. Fail if this happens. |
| */ |
| if (s->objsize >= 65535 * sizeof(void *)) { |
| BUG_ON(s->flags & (SLAB_RED_ZONE | SLAB_POISON | |
| SLAB_STORE_USER | SLAB_DESTROY_BY_RCU)); |
| BUG_ON(s->ctor); |
| } |
| else |
| /* |
| * Enable debugging if selected on the kernel commandline. |
| */ |
| if (slub_debug && (!slub_debug_slabs || |
| strncmp(slub_debug_slabs, s->name, |
| strlen(slub_debug_slabs)) == 0)) |
| s->flags |= slub_debug; |
| } |
| #else |
| static inline void setup_object_debug(struct kmem_cache *s, |
| struct page *page, void *object) {} |
| |
| static inline int alloc_debug_processing(struct kmem_cache *s, |
| struct page *page, void *object, void *addr) { return 0; } |
| |
| static inline int free_debug_processing(struct kmem_cache *s, |
| struct page *page, void *object, void *addr) { return 0; } |
| |
| static inline int slab_pad_check(struct kmem_cache *s, struct page *page) |
| { return 1; } |
| static inline int check_object(struct kmem_cache *s, struct page *page, |
| void *object, int active) { return 1; } |
| static inline void add_full(struct kmem_cache_node *n, struct page *page) {} |
| static inline void kmem_cache_open_debug_check(struct kmem_cache *s) {} |
| #define slub_debug 0 |
| #endif |
| /* |
| * Slab allocation and freeing |
| */ |
| static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node) |
| { |
| struct page * page; |
| int pages = 1 << s->order; |
| |
| if (s->order) |
| flags |= __GFP_COMP; |
| |
| if (s->flags & SLAB_CACHE_DMA) |
| flags |= SLUB_DMA; |
| |
| if (node == -1) |
| page = alloc_pages(flags, s->order); |
| else |
| page = alloc_pages_node(node, flags, s->order); |
| |
| if (!page) |
| return NULL; |
| |
| mod_zone_page_state(page_zone(page), |
| (s->flags & SLAB_RECLAIM_ACCOUNT) ? |
| NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE, |
| pages); |
| |
| return page; |
| } |
| |
| static void setup_object(struct kmem_cache *s, struct page *page, |
| void *object) |
| { |
| setup_object_debug(s, page, object); |
| if (unlikely(s->ctor)) |
| s->ctor(object, s, 0); |
| } |
| |
| static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node) |
| { |
| struct page *page; |
| struct kmem_cache_node *n; |
| void *start; |
| void *end; |
| void *last; |
| void *p; |
| |
| BUG_ON(flags & ~(GFP_DMA | GFP_LEVEL_MASK)); |
| |
| if (flags & __GFP_WAIT) |
| local_irq_enable(); |
| |
| page = allocate_slab(s, flags & GFP_LEVEL_MASK, node); |
| if (!page) |
| goto out; |
| |
| n = get_node(s, page_to_nid(page)); |
| if (n) |
| atomic_long_inc(&n->nr_slabs); |
| page->offset = s->offset / sizeof(void *); |
| page->slab = s; |
| page->flags |= 1 << PG_slab; |
| if (s->flags & (SLAB_DEBUG_FREE | SLAB_RED_ZONE | SLAB_POISON | |
| SLAB_STORE_USER | SLAB_TRACE)) |
| SetSlabDebug(page); |
| |
| start = page_address(page); |
| end = start + s->objects * s->size; |
| |
| if (unlikely(s->flags & SLAB_POISON)) |
| memset(start, POISON_INUSE, PAGE_SIZE << s->order); |
| |
| last = start; |
| for_each_object(p, s, start) { |
| setup_object(s, page, last); |
| set_freepointer(s, last, p); |
| last = p; |
| } |
| setup_object(s, page, last); |
| set_freepointer(s, last, NULL); |
| |
| page->freelist = start; |
| page->lockless_freelist = NULL; |
| page->inuse = 0; |
| out: |
| if (flags & __GFP_WAIT) |
| local_irq_disable(); |
| return page; |
| } |
| |
| static void __free_slab(struct kmem_cache *s, struct page *page) |
| { |
| int pages = 1 << s->order; |
| |
| if (unlikely(SlabDebug(page))) { |
| void *p; |
| |
| slab_pad_check(s, page); |
| for_each_object(p, s, page_address(page)) |
| check_object(s, page, p, 0); |
| } |
| |
| mod_zone_page_state(page_zone(page), |
| (s->flags & SLAB_RECLAIM_ACCOUNT) ? |
| NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE, |
| - pages); |
| |
| page->mapping = NULL; |
| __free_pages(page, s->order); |
| } |
| |
| static void rcu_free_slab(struct rcu_head *h) |
| { |
| struct page *page; |
| |
| page = container_of((struct list_head *)h, struct page, lru); |
| __free_slab(page->slab, page); |
| } |
| |
| static void free_slab(struct kmem_cache *s, struct page *page) |
| { |
| if (unlikely(s->flags & SLAB_DESTROY_BY_RCU)) { |
| /* |
| * RCU free overloads the RCU head over the LRU |
| */ |
| struct rcu_head *head = (void *)&page->lru; |
| |
| call_rcu(head, rcu_free_slab); |
| } else |
| __free_slab(s, page); |
| } |
| |
| static void discard_slab(struct kmem_cache *s, struct page *page) |
| { |
| struct kmem_cache_node *n = get_node(s, page_to_nid(page)); |
| |
| atomic_long_dec(&n->nr_slabs); |
| reset_page_mapcount(page); |
| ClearSlabDebug(page); |
| __ClearPageSlab(page); |
| free_slab(s, page); |
| } |
| |
| /* |
| * Per slab locking using the pagelock |
| */ |
| static __always_inline void slab_lock(struct page *page) |
| { |
| bit_spin_lock(PG_locked, &page->flags); |
| } |
| |
| static __always_inline void slab_unlock(struct page *page) |
| { |
| bit_spin_unlock(PG_locked, &page->flags); |
| } |
| |
| static __always_inline int slab_trylock(struct page *page) |
| { |
| int rc = 1; |
| |
| rc = bit_spin_trylock(PG_locked, &page->flags); |
| return rc; |
| } |
| |
| /* |
| * Management of partially allocated slabs |
| */ |
| static void add_partial_tail(struct kmem_cache_node *n, struct page *page) |
| { |
| spin_lock(&n->list_lock); |
| n->nr_partial++; |
| list_add_tail(&page->lru, &n->partial); |
| spin_unlock(&n->list_lock); |
| } |
| |
| static void add_partial(struct kmem_cache_node *n, struct page *page) |
| { |
| spin_lock(&n->list_lock); |
| n->nr_partial++; |
| list_add(&page->lru, &n->partial); |
| spin_unlock(&n->list_lock); |
| } |
| |
| static void remove_partial(struct kmem_cache *s, |
| struct page *page) |
| { |
| struct kmem_cache_node *n = get_node(s, page_to_nid(page)); |
| |
| spin_lock(&n->list_lock); |
| list_del(&page->lru); |
| n->nr_partial--; |
| spin_unlock(&n->list_lock); |
| } |
| |
| /* |
| * Lock slab and remove from the partial list. |
| * |
| * Must hold list_lock. |
| */ |
| static inline int lock_and_freeze_slab(struct kmem_cache_node *n, struct page *page) |
| { |
| if (slab_trylock(page)) { |
| list_del(&page->lru); |
| n->nr_partial--; |
| SetSlabFrozen(page); |
| return 1; |
| } |
| return 0; |
| } |
| |
| /* |
| * Try to allocate a partial slab from a specific node. |
| */ |
| static struct page *get_partial_node(struct kmem_cache_node *n) |
| { |
| struct page *page; |
| |
| /* |
| * Racy check. If we mistakenly see no partial slabs then we |
| * just allocate an empty slab. If we mistakenly try to get a |
| * partial slab and there is none available then get_partials() |
| * will return NULL. |
| */ |
| if (!n || !n->nr_partial) |
| return NULL; |
| |
| spin_lock(&n->list_lock); |
| list_for_each_entry(page, &n->partial, lru) |
| if (lock_and_freeze_slab(n, page)) |
| goto out; |
| page = NULL; |
| out: |
| spin_unlock(&n->list_lock); |
| return page; |
| } |
| |
| /* |
| * Get a page from somewhere. Search in increasing NUMA distances. |
| */ |
| static struct page *get_any_partial(struct kmem_cache *s, gfp_t flags) |
| { |
| #ifdef CONFIG_NUMA |
| struct zonelist *zonelist; |
| struct zone **z; |
| struct page *page; |
| |
| /* |
| * The defrag ratio allows a configuration of the tradeoffs between |
| * inter node defragmentation and node local allocations. A lower |
| * defrag_ratio increases the tendency to do local allocations |
| * instead of attempting to obtain partial slabs from other nodes. |
| * |
| * If the defrag_ratio is set to 0 then kmalloc() always |
| * returns node local objects. If the ratio is higher then kmalloc() |
| * may return off node objects because partial slabs are obtained |
| * from other nodes and filled up. |
| * |
| * If /sys/slab/xx/defrag_ratio is set to 100 (which makes |
| * defrag_ratio = 1000) then every (well almost) allocation will |
| * first attempt to defrag slab caches on other nodes. This means |
| * scanning over all nodes to look for partial slabs which may be |
| * expensive if we do it every time we are trying to find a slab |
| * with available objects. |
| */ |
| if (!s->defrag_ratio || get_cycles() % 1024 > s->defrag_ratio) |
| return NULL; |
| |
| zonelist = &NODE_DATA(slab_node(current->mempolicy)) |
| ->node_zonelists[gfp_zone(flags)]; |
| for (z = zonelist->zones; *z; z++) { |
| struct kmem_cache_node *n; |
| |
| n = get_node(s, zone_to_nid(*z)); |
| |
| if (n && cpuset_zone_allowed_hardwall(*z, flags) && |
| n->nr_partial > MIN_PARTIAL) { |
| page = get_partial_node(n); |
| if (page) |
| return page; |
| } |
| } |
| #endif |
| return NULL; |
| } |
| |
| /* |
| * Get a partial page, lock it and return it. |
| */ |
| static struct page *get_partial(struct kmem_cache *s, gfp_t flags, int node) |
| { |
| struct page *page; |
| int searchnode = (node == -1) ? numa_node_id() : node; |
| |
| page = get_partial_node(get_node(s, searchnode)); |
| if (page || (flags & __GFP_THISNODE)) |
| return page; |
| |
| return get_any_partial(s, flags); |
| } |
| |
| /* |
| * Move a page back to the lists. |
| * |
| * Must be called with the slab lock held. |
| * |
| * On exit the slab lock will have been dropped. |
| */ |
| static void unfreeze_slab(struct kmem_cache *s, struct page *page) |
| { |
| struct kmem_cache_node *n = get_node(s, page_to_nid(page)); |
| |
| ClearSlabFrozen(page); |
| if (page->inuse) { |
| |
| if (page->freelist) |
| add_partial(n, page); |
| else if (SlabDebug(page) && (s->flags & SLAB_STORE_USER)) |
| add_full(n, page); |
| slab_unlock(page); |
| |
| } else { |
| if (n->nr_partial < MIN_PARTIAL) { |
| /* |
| * Adding an empty slab to the partial slabs in order |
| * to avoid page allocator overhead. This slab needs |
| * to come after the other slabs with objects in |
| * order to fill them up. That way the size of the |
| * partial list stays small. kmem_cache_shrink can |
| * reclaim empty slabs from the partial list. |
| */ |
| add_partial_tail(n, page); |
| slab_unlock(page); |
| } else { |
| slab_unlock(page); |
| discard_slab(s, page); |
| } |
| } |
| } |
| |
| /* |
| * Remove the cpu slab |
| */ |
| static void deactivate_slab(struct kmem_cache *s, struct page *page, int cpu) |
| { |
| /* |
| * Merge cpu freelist into freelist. Typically we get here |
| * because both freelists are empty. So this is unlikely |
| * to occur. |
| */ |
| while (unlikely(page->lockless_freelist)) { |
| void **object; |
| |
| /* Retrieve object from cpu_freelist */ |
| object = page->lockless_freelist; |
| page->lockless_freelist = page->lockless_freelist[page->offset]; |
| |
| /* And put onto the regular freelist */ |
| object[page->offset] = page->freelist; |
| page->freelist = object; |
| page->inuse--; |
| } |
| s->cpu_slab[cpu] = NULL; |
| unfreeze_slab(s, page); |
| } |
| |
| static void flush_slab(struct kmem_cache *s, struct page *page, int cpu) |
| { |
| slab_lock(page); |
| deactivate_slab(s, page, cpu); |
| } |
| |
| /* |
| * Flush cpu slab. |
| * Called from IPI handler with interrupts disabled. |
| */ |
| static void __flush_cpu_slab(struct kmem_cache *s, int cpu) |
| { |
| struct page *page = s->cpu_slab[cpu]; |
| |
| if (likely(page)) |
| flush_slab(s, page, cpu); |
| } |
| |
| static void flush_cpu_slab(void *d) |
| { |
| struct kmem_cache *s = d; |
| int cpu = smp_processor_id(); |
| |
| __flush_cpu_slab(s, cpu); |
| } |
| |
| static void flush_all(struct kmem_cache *s) |
| { |
| #ifdef CONFIG_SMP |
| on_each_cpu(flush_cpu_slab, s, 1, 1); |
| #else |
| unsigned long flags; |
| |
| local_irq_save(flags); |
| flush_cpu_slab(s); |
| local_irq_restore(flags); |
| #endif |
| } |
| |
| /* |
| * Slow path. The lockless freelist is empty or we need to perform |
| * debugging duties. |
| * |
| * Interrupts are disabled. |
| * |
| * Processing is still very fast if new objects have been freed to the |
| * regular freelist. In that case we simply take over the regular freelist |
| * as the lockless freelist and zap the regular freelist. |
| * |
| * If that is not working then we fall back to the partial lists. We take the |
| * first element of the freelist as the object to allocate now and move the |
| * rest of the freelist to the lockless freelist. |
| * |
| * And if we were unable to get a new slab from the partial slab lists then |
| * we need to allocate a new slab. This is slowest path since we may sleep. |
| */ |
| static void *__slab_alloc(struct kmem_cache *s, |
| gfp_t gfpflags, int node, void *addr, struct page *page) |
| { |
| void **object; |
| int cpu = smp_processor_id(); |
| |
| if (!page) |
| goto new_slab; |
| |
| slab_lock(page); |
| if (unlikely(node != -1 && page_to_nid(page) != node)) |
| goto another_slab; |
| load_freelist: |
| object = page->freelist; |
| if (unlikely(!object)) |
| goto another_slab; |
| if (unlikely(SlabDebug(page))) |
| goto debug; |
| |
| object = page->freelist; |
| page->lockless_freelist = object[page->offset]; |
| page->inuse = s->objects; |
| page->freelist = NULL; |
| slab_unlock(page); |
| return object; |
| |
| another_slab: |
| deactivate_slab(s, page, cpu); |
| |
| new_slab: |
| page = get_partial(s, gfpflags, node); |
| if (page) { |
| s->cpu_slab[cpu] = page; |
| goto load_freelist; |
| } |
| |
| page = new_slab(s, gfpflags, node); |
| if (page) { |
| cpu = smp_processor_id(); |
| if (s->cpu_slab[cpu]) { |
| /* |
| * Someone else populated the cpu_slab while we |
| * enabled interrupts, or we have gotten scheduled |
| * on another cpu. The page may not be on the |
| * requested node even if __GFP_THISNODE was |
| * specified. So we need to recheck. |
| */ |
| if (node == -1 || |
| page_to_nid(s->cpu_slab[cpu]) == node) { |
| /* |
| * Current cpuslab is acceptable and we |
| * want the current one since its cache hot |
| */ |
| discard_slab(s, page); |
| page = s->cpu_slab[cpu]; |
| slab_lock(page); |
| goto load_freelist; |
| } |
| /* New slab does not fit our expectations */ |
| flush_slab(s, s->cpu_slab[cpu], cpu); |
| } |
| slab_lock(page); |
| SetSlabFrozen(page); |
| s->cpu_slab[cpu] = page; |
| goto load_freelist; |
| } |
| return NULL; |
| debug: |
| object = page->freelist; |
| if (!alloc_debug_processing(s, page, object, addr)) |
| goto another_slab; |
| |
| page->inuse++; |
| page->freelist = object[page->offset]; |
| slab_unlock(page); |
| return object; |
| } |
| |
| /* |
| * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc) |
| * have the fastpath folded into their functions. So no function call |
| * overhead for requests that can be satisfied on the fastpath. |
| * |
| * The fastpath works by first checking if the lockless freelist can be used. |
| * If not then __slab_alloc is called for slow processing. |
| * |
| * Otherwise we can simply pick the next object from the lockless free list. |
| */ |
| static void __always_inline *slab_alloc(struct kmem_cache *s, |
| gfp_t gfpflags, int node, void *addr) |
| { |
| struct page *page; |
| void **object; |
| unsigned long flags; |
| |
| local_irq_save(flags); |
| page = s->cpu_slab[smp_processor_id()]; |
| if (unlikely(!page || !page->lockless_freelist || |
| (node != -1 && page_to_nid(page) != node))) |
| |
| object = __slab_alloc(s, gfpflags, node, addr, page); |
| |
| else { |
| object = page->lockless_freelist; |
| page->lockless_freelist = object[page->offset]; |
| } |
| local_irq_restore(flags); |
| return object; |
| } |
| |
| void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags) |
| { |
| return slab_alloc(s, gfpflags, -1, __builtin_return_address(0)); |
| } |
| EXPORT_SYMBOL(kmem_cache_alloc); |
| |
| #ifdef CONFIG_NUMA |
| void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node) |
| { |
| return slab_alloc(s, gfpflags, node, __builtin_return_address(0)); |
| } |
| EXPORT_SYMBOL(kmem_cache_alloc_node); |
| #endif |
| |
| /* |
| * Slow patch handling. This may still be called frequently since objects |
| * have a longer lifetime than the cpu slabs in most processing loads. |
| * |
| * So we still attempt to reduce cache line usage. Just take the slab |
| * lock and free the item. If there is no additional partial page |
| * handling required then we can return immediately. |
| */ |
| static void __slab_free(struct kmem_cache *s, struct page *page, |
| void *x, void *addr) |
| { |
| void *prior; |
| void **object = (void *)x; |
| |
| slab_lock(page); |
| |
| if (unlikely(SlabDebug(page))) |
| goto debug; |
| checks_ok: |
| prior = object[page->offset] = page->freelist; |
| page->freelist = object; |
| page->inuse--; |
| |
| if (unlikely(SlabFrozen(page))) |
| goto out_unlock; |
| |
| if (unlikely(!page->inuse)) |
| goto slab_empty; |
| |
| /* |
| * Objects left in the slab. If it |
| * was not on the partial list before |
| * then add it. |
| */ |
| if (unlikely(!prior)) |
| add_partial(get_node(s, page_to_nid(page)), page); |
| |
| out_unlock: |
| slab_unlock(page); |
| return; |
| |
| slab_empty: |
| if (prior) |
| /* |
| * Slab still on the partial list. |
| */ |
| remove_partial(s, page); |
| |
| slab_unlock(page); |
| discard_slab(s, page); |
| return; |
| |
| debug: |
| if (!free_debug_processing(s, page, x, addr)) |
| goto out_unlock; |
| goto checks_ok; |
| } |
| |
| /* |
| * Fastpath with forced inlining to produce a kfree and kmem_cache_free that |
| * can perform fastpath freeing without additional function calls. |
| * |
| * The fastpath is only possible if we are freeing to the current cpu slab |
| * of this processor. This typically the case if we have just allocated |
| * the item before. |
| * |
| * If fastpath is not possible then fall back to __slab_free where we deal |
| * with all sorts of special processing. |
| */ |
| static void __always_inline slab_free(struct kmem_cache *s, |
| struct page *page, void *x, void *addr) |
| { |
| void **object = (void *)x; |
| unsigned long flags; |
| |
| local_irq_save(flags); |
| if (likely(page == s->cpu_slab[smp_processor_id()] && |
| !SlabDebug(page))) { |
| object[page->offset] = page->lockless_freelist; |
| page->lockless_freelist = object; |
| } else |
| __slab_free(s, page, x, addr); |
| |
| local_irq_restore(flags); |
| } |
| |
| void kmem_cache_free(struct kmem_cache *s, void *x) |
| { |
| struct page *page; |
| |
| page = virt_to_head_page(x); |
| |
| slab_free(s, page, x, __builtin_return_address(0)); |
| } |
| EXPORT_SYMBOL(kmem_cache_free); |
| |
| /* Figure out on which slab object the object resides */ |
| static struct page *get_object_page(const void *x) |
| { |
| struct page *page = virt_to_head_page(x); |
| |
| if (!PageSlab(page)) |
| return NULL; |
| |
| return page; |
| } |
| |
| /* |
| * Object placement in a slab is made very easy because we always start at |
| * offset 0. If we tune the size of the object to the alignment then we can |
| * get the required alignment by putting one properly sized object after |
| * another. |
| * |
| * Notice that the allocation order determines the sizes of the per cpu |
| * caches. Each processor has always one slab available for allocations. |
| * Increasing the allocation order reduces the number of times that slabs |
| * must be moved on and off the partial lists and is therefore a factor in |
| * locking overhead. |
| */ |
| |
| /* |
| * Mininum / Maximum order of slab pages. This influences locking overhead |
| * and slab fragmentation. A higher order reduces the number of partial slabs |
| * and increases the number of allocations possible without having to |
| * take the list_lock. |
| */ |
| static int slub_min_order; |
| static int slub_max_order = DEFAULT_MAX_ORDER; |
| static int slub_min_objects = DEFAULT_MIN_OBJECTS; |
| |
| /* |
| * Merge control. If this is set then no merging of slab caches will occur. |
| * (Could be removed. This was introduced to pacify the merge skeptics.) |
| */ |
| static int slub_nomerge; |
| |
| /* |
| * Calculate the order of allocation given an slab object size. |
| * |
| * The order of allocation has significant impact on performance and other |
| * system components. Generally order 0 allocations should be preferred since |
| * order 0 does not cause fragmentation in the page allocator. Larger objects |
| * be problematic to put into order 0 slabs because there may be too much |
| * unused space left. We go to a higher order if more than 1/8th of the slab |
| * would be wasted. |
| * |
| * In order to reach satisfactory performance we must ensure that a minimum |
| * number of objects is in one slab. Otherwise we may generate too much |
| * activity on the partial lists which requires taking the list_lock. This is |
| * less a concern for large slabs though which are rarely used. |
| * |
| * slub_max_order specifies the order where we begin to stop considering the |
| * number of objects in a slab as critical. If we reach slub_max_order then |
| * we try to keep the page order as low as possible. So we accept more waste |
| * of space in favor of a small page order. |
| * |
| * Higher order allocations also allow the placement of more objects in a |
| * slab and thereby reduce object handling overhead. If the user has |
| * requested a higher mininum order then we start with that one instead of |
| * the smallest order which will fit the object. |
| */ |
| static inline int slab_order(int size, int min_objects, |
| int max_order, int fract_leftover) |
| { |
| int order; |
| int rem; |
| int min_order = slub_min_order; |
| |
| /* |
| * If we would create too many object per slab then reduce |
| * the slab order even if it goes below slub_min_order. |
| */ |
| while (min_order > 0 && |
| (PAGE_SIZE << min_order) >= MAX_OBJECTS_PER_SLAB * size) |
| min_order--; |
| |
| for (order = max(min_order, |
| fls(min_objects * size - 1) - PAGE_SHIFT); |
| order <= max_order; order++) { |
| |
| unsigned long slab_size = PAGE_SIZE << order; |
| |
| if (slab_size < min_objects * size) |
| continue; |
| |
| rem = slab_size % size; |
| |
| if (rem <= slab_size / fract_leftover) |
| break; |
| |
| /* If the next size is too high then exit now */ |
| if (slab_size * 2 >= MAX_OBJECTS_PER_SLAB * size) |
| break; |
| } |
| |
| return order; |
| } |
| |
| static inline int calculate_order(int size) |
| { |
| int order; |
| int min_objects; |
| int fraction; |
| |
| /* |
| * Attempt to find best configuration for a slab. This |
| * works by first attempting to generate a layout with |
| * the best configuration and backing off gradually. |
| * |
| * First we reduce the acceptable waste in a slab. Then |
| * we reduce the minimum objects required in a slab. |
| */ |
| min_objects = slub_min_objects; |
| while (min_objects > 1) { |
| fraction = 8; |
| while (fraction >= 4) { |
| order = slab_order(size, min_objects, |
| slub_max_order, fraction); |
| if (order <= slub_max_order) |
| return order; |
| fraction /= 2; |
| } |
| min_objects /= 2; |
| } |
| |
| /* |
| * We were unable to place multiple objects in a slab. Now |
| * lets see if we can place a single object there. |
| */ |
| order = slab_order(size, 1, slub_max_order, 1); |
| if (order <= slub_max_order) |
| return order; |
| |
| /* |
| * Doh this slab cannot be placed using slub_max_order. |
| */ |
| order = slab_order(size, 1, MAX_ORDER, 1); |
| if (order <= MAX_ORDER) |
| return order; |
| return -ENOSYS; |
| } |
| |
| /* |
| * Figure out what the alignment of the objects will be. |
| */ |
| static unsigned long calculate_alignment(unsigned long flags, |
| unsigned long align, unsigned long size) |
| { |
| /* |
| * If the user wants hardware cache aligned objects then |
| * follow that suggestion if the object is sufficiently |
| * large. |
| * |
| * The hardware cache alignment cannot override the |
| * specified alignment though. If that is greater |
| * then use it. |
| */ |
| if ((flags & SLAB_HWCACHE_ALIGN) && |
| size > cache_line_size() / 2) |
| return max_t(unsigned long, align, cache_line_size()); |
| |
| if (align < ARCH_SLAB_MINALIGN) |
| return ARCH_SLAB_MINALIGN; |
| |
| return ALIGN(align, sizeof(void *)); |
| } |
| |
| static void init_kmem_cache_node(struct kmem_cache_node *n) |
| { |
| n->nr_partial = 0; |
| atomic_long_set(&n->nr_slabs, 0); |
| spin_lock_init(&n->list_lock); |
| INIT_LIST_HEAD(&n->partial); |
| INIT_LIST_HEAD(&n->full); |
| } |
| |
| #ifdef CONFIG_NUMA |
| /* |
| * No kmalloc_node yet so do it by hand. We know that this is the first |
| * slab on the node for this slabcache. There are no concurrent accesses |
| * possible. |
| * |
| * Note that this function only works on the kmalloc_node_cache |
| * when allocating for the kmalloc_node_cache. |
| */ |
| static struct kmem_cache_node * __init early_kmem_cache_node_alloc(gfp_t gfpflags, |
| int node) |
| { |
| struct page *page; |
| struct kmem_cache_node *n; |
| |
| BUG_ON(kmalloc_caches->size < sizeof(struct kmem_cache_node)); |
| |
| page = new_slab(kmalloc_caches, gfpflags | GFP_THISNODE, node); |
| |
| BUG_ON(!page); |
| n = page->freelist; |
| BUG_ON(!n); |
| page->freelist = get_freepointer(kmalloc_caches, n); |
| page->inuse++; |
| kmalloc_caches->node[node] = n; |
| init_object(kmalloc_caches, n, 1); |
| init_tracking(kmalloc_caches, n); |
| init_kmem_cache_node(n); |
| atomic_long_inc(&n->nr_slabs); |
| add_partial(n, page); |
| |
| /* |
| * new_slab() disables interupts. If we do not reenable interrupts here |
| * then bootup would continue with interrupts disabled. |
| */ |
| local_irq_enable(); |
| return n; |
| } |
| |
| static void free_kmem_cache_nodes(struct kmem_cache *s) |
| { |
| int node; |
| |
| for_each_online_node(node) { |
| struct kmem_cache_node *n = s->node[node]; |
| if (n && n != &s->local_node) |
| kmem_cache_free(kmalloc_caches, n); |
| s->node[node] = NULL; |
| } |
| } |
| |
| static int init_kmem_cache_nodes(struct kmem_cache *s, gfp_t gfpflags) |
| { |
| int node; |
| int local_node; |
| |
| if (slab_state >= UP) |
| local_node = page_to_nid(virt_to_page(s)); |
| else |
| local_node = 0; |
| |
| for_each_online_node(node) { |
| struct kmem_cache_node *n; |
| |
| if (local_node == node) |
| n = &s->local_node; |
| else { |
| if (slab_state == DOWN) { |
| n = early_kmem_cache_node_alloc(gfpflags, |
| node); |
| continue; |
| } |
| n = kmem_cache_alloc_node(kmalloc_caches, |
| gfpflags, node); |
| |
| if (!n) { |
| free_kmem_cache_nodes(s); |
| return 0; |
| } |
| |
| } |
| s->node[node] = n; |
| init_kmem_cache_node(n); |
| } |
| return 1; |
| } |
| #else |
| static void free_kmem_cache_nodes(struct kmem_cache *s) |
| { |
| } |
| |
| static int init_kmem_cache_nodes(struct kmem_cache *s, gfp_t gfpflags) |
| { |
| init_kmem_cache_node(&s->local_node); |
| return 1; |
| } |
| #endif |
| |
| /* |
| * calculate_sizes() determines the order and the distribution of data within |
| * a slab object. |
| */ |
| static int calculate_sizes(struct kmem_cache *s) |
| { |
| unsigned long flags = s->flags; |
| unsigned long size = s->objsize; |
| unsigned long align = s->align; |
| |
| /* |
| * Determine if we can poison the object itself. If the user of |
| * the slab may touch the object after free or before allocation |
| * then we should never poison the object itself. |
| */ |
| if ((flags & SLAB_POISON) && !(flags & SLAB_DESTROY_BY_RCU) && |
| !s->ctor) |
| s->flags |= __OBJECT_POISON; |
| else |
| s->flags &= ~__OBJECT_POISON; |
| |
| /* |
| * Round up object size to the next word boundary. We can only |
| * place the free pointer at word boundaries and this determines |
| * the possible location of the free pointer. |
| */ |
| size = ALIGN(size, sizeof(void *)); |
| |
| #ifdef CONFIG_SLUB_DEBUG |
| /* |
| * If we are Redzoning then check if there is some space between the |
| * end of the object and the free pointer. If not then add an |
| * additional word to have some bytes to store Redzone information. |
| */ |
| if ((flags & SLAB_RED_ZONE) && size == s->objsize) |
| size += sizeof(void *); |
| #endif |
| |
| /* |
| * With that we have determined the number of bytes in actual use |
| * by the object. This is the potential offset to the free pointer. |
| */ |
| s->inuse = size; |
| |
| if (((flags & (SLAB_DESTROY_BY_RCU | SLAB_POISON)) || |
| s->ctor)) { |
| /* |
| * Relocate free pointer after the object if it is not |
| * permitted to overwrite the first word of the object on |
| * kmem_cache_free. |
| * |
| * This is the case if we do RCU, have a constructor or |
| * destructor or are poisoning the objects. |
| */ |
| s->offset = size; |
| size += sizeof(void *); |
| } |
| |
| #ifdef CONFIG_SLUB_DEBUG |
| if (flags & SLAB_STORE_USER) |
| /* |
| * Need to store information about allocs and frees after |
| * the object. |
| */ |
| size += 2 * sizeof(struct track); |
| |
| if (flags & SLAB_RED_ZONE) |
| /* |
| * Add some empty padding so that we can catch |
| * overwrites from earlier objects rather than let |
| * tracking information or the free pointer be |
| * corrupted if an user writes before the start |
| * of the object. |
| */ |
| size += sizeof(void *); |
| #endif |
| |
| /* |
| * Determine the alignment based on various parameters that the |
| * user specified and the dynamic determination of cache line size |
| * on bootup. |
| */ |
| align = calculate_alignment(flags, align, s->objsize); |
| |
| /* |
| * SLUB stores one object immediately after another beginning from |
| * offset 0. In order to align the objects we have to simply size |
| * each object to conform to the alignment. |
| */ |
| size = ALIGN(size, align); |
| s->size = size; |
| |
| s->order = calculate_order(size); |
| if (s->order < 0) |
| return 0; |
| |
| /* |
| * Determine the number of objects per slab |
| */ |
| s->objects = (PAGE_SIZE << s->order) / size; |
| |
| /* |
| * Verify that the number of objects is within permitted limits. |
| * The page->inuse field is only 16 bit wide! So we cannot have |
| * more than 64k objects per slab. |
| */ |
| if (!s->objects || s->objects > MAX_OBJECTS_PER_SLAB) |
| return 0; |
| return 1; |
| |
| } |
| |
| static int kmem_cache_open(struct kmem_cache *s, gfp_t gfpflags, |
| const char *name, size_t size, |
| size_t align, unsigned long flags, |
| void (*ctor)(void *, struct kmem_cache *, unsigned long)) |
| { |
| memset(s, 0, kmem_size); |
| s->name = name; |
| s->ctor = ctor; |
| s->objsize = size; |
| s->flags = flags; |
| s->align = align; |
| kmem_cache_open_debug_check(s); |
| |
| if (!calculate_sizes(s)) |
| goto error; |
| |
| s->refcount = 1; |
| #ifdef CONFIG_NUMA |
| s->defrag_ratio = 100; |
| #endif |
| |
| if (init_kmem_cache_nodes(s, gfpflags & ~SLUB_DMA)) |
| return 1; |
| error: |
| if (flags & SLAB_PANIC) |
| panic("Cannot create slab %s size=%lu realsize=%u " |
| "order=%u offset=%u flags=%lx\n", |
| s->name, (unsigned long)size, s->size, s->order, |
| s->offset, flags); |
| return 0; |
| } |
| |
| /* |
| * Check if a given pointer is valid |
| */ |
| int kmem_ptr_validate(struct kmem_cache *s, const void *object) |
| { |
| struct page * page; |
| |
| page = get_object_page(object); |
| |
| if (!page || s != page->slab) |
| /* No slab or wrong slab */ |
| return 0; |
| |
| if (!check_valid_pointer(s, page, object)) |
| return 0; |
| |
| /* |
| * We could also check if the object is on the slabs freelist. |
| * But this would be too expensive and it seems that the main |
| * purpose of kmem_ptr_valid is to check if the object belongs |
| * to a certain slab. |
| */ |
| return 1; |
| } |
| EXPORT_SYMBOL(kmem_ptr_validate); |
| |
| /* |
| * Determine the size of a slab object |
| */ |
| unsigned int kmem_cache_size(struct kmem_cache *s) |
| { |
| return s->objsize; |
| } |
| EXPORT_SYMBOL(kmem_cache_size); |
| |
| const char *kmem_cache_name(struct kmem_cache *s) |
| { |
| return s->name; |
| } |
| EXPORT_SYMBOL(kmem_cache_name); |
| |
| /* |
| * Attempt to free all slabs on a node. Return the number of slabs we |
| * were unable to free. |
| */ |
| static int free_list(struct kmem_cache *s, struct kmem_cache_node *n, |
| struct list_head *list) |
| { |
| int slabs_inuse = 0; |
| unsigned long flags; |
| struct page *page, *h; |
| |
| spin_lock_irqsave(&n->list_lock, flags); |
| list_for_each_entry_safe(page, h, list, lru) |
| if (!page->inuse) { |
| list_del(&page->lru); |
| discard_slab(s, page); |
| } else |
| slabs_inuse++; |
| spin_unlock_irqrestore(&n->list_lock, flags); |
| return slabs_inuse; |
| } |
| |
| /* |
| * Release all resources used by a slab cache. |
| */ |
| static int kmem_cache_close(struct kmem_cache *s) |
| { |
| int node; |
| |
| flush_all(s); |
| |
| /* Attempt to free all objects */ |
| for_each_online_node(node) { |
| struct kmem_cache_node *n = get_node(s, node); |
| |
| n->nr_partial -= free_list(s, n, &n->partial); |
| if (atomic_long_read(&n->nr_slabs)) |
| return 1; |
| } |
| free_kmem_cache_nodes(s); |
| return 0; |
| } |
| |
| /* |
| * Close a cache and release the kmem_cache structure |
| * (must be used for caches created using kmem_cache_create) |
| */ |
| void kmem_cache_destroy(struct kmem_cache *s) |
| { |
| down_write(&slub_lock); |
| s->refcount--; |
| if (!s->refcount) { |
| list_del(&s->list); |
| if (kmem_cache_close(s)) |
| WARN_ON(1); |
| sysfs_slab_remove(s); |
| kfree(s); |
| } |
| up_write(&slub_lock); |
| } |
| EXPORT_SYMBOL(kmem_cache_destroy); |
| |
| /******************************************************************** |
| * Kmalloc subsystem |
| *******************************************************************/ |
| |
| struct kmem_cache kmalloc_caches[KMALLOC_SHIFT_HIGH + 1] __cacheline_aligned; |
| EXPORT_SYMBOL(kmalloc_caches); |
| |
| #ifdef CONFIG_ZONE_DMA |
| static struct kmem_cache *kmalloc_caches_dma[KMALLOC_SHIFT_HIGH + 1]; |
| #endif |
| |
| static int __init setup_slub_min_order(char *str) |
| { |
| get_option (&str, &slub_min_order); |
| |
| return 1; |
| } |
| |
| __setup("slub_min_order=", setup_slub_min_order); |
| |
| static int __init setup_slub_max_order(char *str) |
| { |
| get_option (&str, &slub_max_order); |
| |
| return 1; |
| } |
| |
| __setup("slub_max_order=", setup_slub_max_order); |
| |
| static int __init setup_slub_min_objects(char *str) |
| { |
| get_option (&str, &slub_min_objects); |
| |
| return 1; |
| } |
| |
| __setup("slub_min_objects=", setup_slub_min_objects); |
| |
| static int __init setup_slub_nomerge(char *str) |
| { |
| slub_nomerge = 1; |
| return 1; |
| } |
| |
| __setup("slub_nomerge", setup_slub_nomerge); |
| |
| static struct kmem_cache *create_kmalloc_cache(struct kmem_cache *s, |
| const char *name, int size, gfp_t gfp_flags) |
| { |
| unsigned int flags = 0; |
| |
| if (gfp_flags & SLUB_DMA) |
| flags = SLAB_CACHE_DMA; |
| |
| down_write(&slub_lock); |
| if (!kmem_cache_open(s, gfp_flags, name, size, ARCH_KMALLOC_MINALIGN, |
| flags, NULL)) |
| goto panic; |
| |
| list_add(&s->list, &slab_caches); |
| up_write(&slub_lock); |
| if (sysfs_slab_add(s)) |
| goto panic; |
| return s; |
| |
| panic: |
| panic("Creation of kmalloc slab %s size=%d failed.\n", name, size); |
| } |
| |
| static struct kmem_cache *get_slab(size_t size, gfp_t flags) |
| { |
| int index = kmalloc_index(size); |
| |
| if (!index) |
| return NULL; |
| |
| /* Allocation too large? */ |
| BUG_ON(index < 0); |
| |
| #ifdef CONFIG_ZONE_DMA |
| if ((flags & SLUB_DMA)) { |
| struct kmem_cache *s; |
| struct kmem_cache *x; |
| char *text; |
| size_t realsize; |
| |
| s = kmalloc_caches_dma[index]; |
| if (s) |
| return s; |
| |
| /* Dynamically create dma cache */ |
| x = kmalloc(kmem_size, flags & ~SLUB_DMA); |
| if (!x) |
| panic("Unable to allocate memory for dma cache\n"); |
| |
| if (index <= KMALLOC_SHIFT_HIGH) |
| realsize = 1 << index; |
| else { |
| if (index == 1) |
| realsize = 96; |
| else |
| realsize = 192; |
| } |
| |
| text = kasprintf(flags & ~SLUB_DMA, "kmalloc_dma-%d", |
| (unsigned int)realsize); |
| s = create_kmalloc_cache(x, text, realsize, flags); |
| kmalloc_caches_dma[index] = s; |
| return s; |
| } |
| #endif |
| return &kmalloc_caches[index]; |
| } |
| |
| void *__kmalloc(size_t size, gfp_t flags) |
| { |
| struct kmem_cache *s = get_slab(size, flags); |
| |
| if (s) |
| return slab_alloc(s, flags, -1, __builtin_return_address(0)); |
| return ZERO_SIZE_PTR; |
| } |
| EXPORT_SYMBOL(__kmalloc); |
| |
| #ifdef CONFIG_NUMA |
| void *__kmalloc_node(size_t size, gfp_t flags, int node) |
| { |
| struct kmem_cache *s = get_slab(size, flags); |
| |
| if (s) |
| return slab_alloc(s, flags, node, __builtin_return_address(0)); |
| return ZERO_SIZE_PTR; |
| } |
| EXPORT_SYMBOL(__kmalloc_node); |
| #endif |
| |
| size_t ksize(const void *object) |
| { |
| struct page *page; |
| struct kmem_cache *s; |
| |
| if (object == ZERO_SIZE_PTR) |
| return 0; |
| |
| page = get_object_page(object); |
| BUG_ON(!page); |
| s = page->slab; |
| BUG_ON(!s); |
| |
| /* |
| * Debugging requires use of the padding between object |
| * and whatever may come after it. |
| */ |
| if (s->flags & (SLAB_RED_ZONE | SLAB_POISON)) |
| return s->objsize; |
| |
| /* |
| * If we have the need to store the freelist pointer |
| * back there or track user information then we can |
| * only use the space before that information. |
| */ |
| if (s->flags & (SLAB_DESTROY_BY_RCU | SLAB_STORE_USER)) |
| return s->inuse; |
| |
| /* |
| * Else we can use all the padding etc for the allocation |
| */ |
| return s->size; |
| } |
| EXPORT_SYMBOL(ksize); |
| |
| void kfree(const void *x) |
| { |
| struct kmem_cache *s; |
| struct page *page; |
| |
| /* |
| * This has to be an unsigned comparison. According to Linus |
| * some gcc version treat a pointer as a signed entity. Then |
| * this comparison would be true for all "negative" pointers |
| * (which would cover the whole upper half of the address space). |
| */ |
| if ((unsigned long)x <= (unsigned long)ZERO_SIZE_PTR) |
| return; |
| |
| page = virt_to_head_page(x); |
| s = page->slab; |
| |
| slab_free(s, page, (void *)x, __builtin_return_address(0)); |
| } |
| EXPORT_SYMBOL(kfree); |
| |
| /* |
| * kmem_cache_shrink removes empty slabs from the partial lists and sorts |
| * the remaining slabs by the number of items in use. The slabs with the |
| * most items in use come first. New allocations will then fill those up |
| * and thus they can be removed from the partial lists. |
| * |
| * The slabs with the least items are placed last. This results in them |
| * being allocated from last increasing the chance that the last objects |
| * are freed in them. |
| */ |
| int kmem_cache_shrink(struct kmem_cache *s) |
| { |
| int node; |
| int i; |
| struct kmem_cache_node *n; |
| struct page *page; |
| struct page *t; |
| struct list_head *slabs_by_inuse = |
| kmalloc(sizeof(struct list_head) * s->objects, GFP_KERNEL); |
| unsigned long flags; |
| |
| if (!slabs_by_inuse) |
| return -ENOMEM; |
| |
| flush_all(s); |
| for_each_online_node(node) { |
| n = get_node(s, node); |
| |
| if (!n->nr_partial) |
| continue; |
| |
| for (i = 0; i < s->objects; i++) |
| INIT_LIST_HEAD(slabs_by_inuse + i); |
| |
| spin_lock_irqsave(&n->list_lock, flags); |
| |
| /* |
| * Build lists indexed by the items in use in each slab. |
| * |
| * Note that concurrent frees may occur while we hold the |
| * list_lock. page->inuse here is the upper limit. |
| */ |
| list_for_each_entry_safe(page, t, &n->partial, lru) { |
| if (!page->inuse && slab_trylock(page)) { |
| /* |
| * Must hold slab lock here because slab_free |
| * may have freed the last object and be |
| * waiting to release the slab. |
| */ |
| list_del(&page->lru); |
| n->nr_partial--; |
| slab_unlock(page); |
| discard_slab(s, page); |
| } else { |
| if (n->nr_partial > MAX_PARTIAL) |
| list_move(&page->lru, |
| slabs_by_inuse + page->inuse); |
| } |
| } |
| |
| if (n->nr_partial <= MAX_PARTIAL) |
| goto out; |
| |
| /* |
| * Rebuild the partial list with the slabs filled up most |
| * first and the least used slabs at the end. |
| */ |
| for (i = s->objects - 1; i >= 0; i--) |
| list_splice(slabs_by_inuse + i, n->partial.prev); |
| |
| out: |
| spin_unlock_irqrestore(&n->list_lock, flags); |
| } |
| |
| kfree(slabs_by_inuse); |
| return 0; |
| } |
| EXPORT_SYMBOL(kmem_cache_shrink); |
| |
| /** |
| * krealloc - reallocate memory. The contents will remain unchanged. |
| * @p: object to reallocate memory for. |
| * @new_size: how many bytes of memory are required. |
| * @flags: the type of memory to allocate. |
| * |
| * The contents of the object pointed to are preserved up to the |
| * lesser of the new and old sizes. If @p is %NULL, krealloc() |
| * behaves exactly like kmalloc(). If @size is 0 and @p is not a |
| * %NULL pointer, the object pointed to is freed. |
| */ |
| void *krealloc(const void *p, size_t new_size, gfp_t flags) |
| { |
| void *ret; |
| size_t ks; |
| |
| if (unlikely(!p || p == ZERO_SIZE_PTR)) |
| return kmalloc(new_size, flags); |
| |
| if (unlikely(!new_size)) { |
| kfree(p); |
| return ZERO_SIZE_PTR; |
| } |
| |
| ks = ksize(p); |
| if (ks >= new_size) |
| return (void *)p; |
| |
| ret = kmalloc(new_size, flags); |
| if (ret) { |
| memcpy(ret, p, min(new_size, ks)); |
| kfree(p); |
| } |
| return ret; |
| } |
| EXPORT_SYMBOL(krealloc); |
| |
| /******************************************************************** |
| * Basic setup of slabs |
| *******************************************************************/ |
| |
| void __init kmem_cache_init(void) |
| { |
| int i; |
| int caches = 0; |
| |
| #ifdef CONFIG_NUMA |
| /* |
| * Must first have the slab cache available for the allocations of the |
| * struct kmem_cache_node's. There is special bootstrap code in |
| * kmem_cache_open for slab_state == DOWN. |
| */ |
| create_kmalloc_cache(&kmalloc_caches[0], "kmem_cache_node", |
| sizeof(struct kmem_cache_node), GFP_KERNEL); |
| kmalloc_caches[0].refcount = -1; |
| caches++; |
| #endif |
| |
| /* Able to allocate the per node structures */ |
| slab_state = PARTIAL; |
| |
| /* Caches that are not of the two-to-the-power-of size */ |
| if (KMALLOC_MIN_SIZE <= 64) { |
| create_kmalloc_cache(&kmalloc_caches[1], |
| "kmalloc-96", 96, GFP_KERNEL); |
| caches++; |
| } |
| if (KMALLOC_MIN_SIZE <= 128) { |
| create_kmalloc_cache(&kmalloc_caches[2], |
| "kmalloc-192", 192, GFP_KERNEL); |
| caches++; |
| } |
| |
| for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++) { |
| create_kmalloc_cache(&kmalloc_caches[i], |
| "kmalloc", 1 << i, GFP_KERNEL); |
| caches++; |
| } |
| |
| slab_state = UP; |
| |
| /* Provide the correct kmalloc names now that the caches are up */ |
| for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++) |
| kmalloc_caches[i]. name = |
| kasprintf(GFP_KERNEL, "kmalloc-%d", 1 << i); |
| |
| #ifdef CONFIG_SMP |
| register_cpu_notifier(&slab_notifier); |
| #endif |
| |
| kmem_size = offsetof(struct kmem_cache, cpu_slab) + |
| nr_cpu_ids * sizeof(struct page *); |
| |
| printk(KERN_INFO "SLUB: Genslabs=%d, HWalign=%d, Order=%d-%d, MinObjects=%d," |
| " CPUs=%d, Nodes=%d\n", |
| caches, cache_line_size(), |
| slub_min_order, slub_max_order, slub_min_objects, |
| nr_cpu_ids, nr_node_ids); |
| } |
| |
| /* |
| * Find a mergeable slab cache |
| */ |
| static int slab_unmergeable(struct kmem_cache *s) |
| { |
| if (slub_nomerge || (s->flags & SLUB_NEVER_MERGE)) |
| return 1; |
| |
| if (s->ctor) |
| return 1; |
| |
| /* |
| * We may have set a slab to be unmergeable during bootstrap. |
| */ |
| if (s->refcount < 0) |
| return 1; |
| |
| return 0; |
| } |
| |
| static struct kmem_cache *find_mergeable(size_t size, |
| size_t align, unsigned long flags, |
| void (*ctor)(void *, struct kmem_cache *, unsigned long)) |
| { |
| struct kmem_cache *s; |
| |
| if (slub_nomerge || (flags & SLUB_NEVER_MERGE)) |
| return NULL; |
| |
| if (ctor) |
| return NULL; |
| |
| size = ALIGN(size, sizeof(void *)); |
| align = calculate_alignment(flags, align, size); |
| size = ALIGN(size, align); |
| |
| list_for_each_entry(s, &slab_caches, list) { |
| if (slab_unmergeable(s)) |
| continue; |
| |
| if (size > s->size) |
| continue; |
| |
| if (((flags | slub_debug) & SLUB_MERGE_SAME) != |
| (s->flags & SLUB_MERGE_SAME)) |
| continue; |
| /* |
| * Check if alignment is compatible. |
| * Courtesy of Adrian Drzewiecki |
| */ |
| if ((s->size & ~(align -1)) != s->size) |
| continue; |
| |
| if (s->size - size >= sizeof(void *)) |
| continue; |
| |
| return s; |
| } |
| return NULL; |
| } |
| |
| struct kmem_cache *kmem_cache_create(const char *name, size_t size, |
| size_t align, unsigned long flags, |
| void (*ctor)(void *, struct kmem_cache *, unsigned long), |
| void (*dtor)(void *, struct kmem_cache *, unsigned long)) |
| { |
| struct kmem_cache *s; |
| |
| BUG_ON(dtor); |
| down_write(&slub_lock); |
| s = find_mergeable(size, align, flags, ctor); |
| if (s) { |
| s->refcount++; |
| /* |
| * Adjust the object sizes so that we clear |
| * the complete object on kzalloc. |
| */ |
| s->objsize = max(s->objsize, (int)size); |
| s->inuse = max_t(int, s->inuse, ALIGN(size, sizeof(void *))); |
| if (sysfs_slab_alias(s, name)) |
| goto err; |
| } else { |
| s = kmalloc(kmem_size, GFP_KERNEL); |
| if (s && kmem_cache_open(s, GFP_KERNEL, name, |
| size, align, flags, ctor)) { |
| if (sysfs_slab_add(s)) { |
| kfree(s); |
| goto err; |
| } |
| list_add(&s->list, &slab_caches); |
| } else |
| kfree(s); |
| } |
| up_write(&slub_lock); |
| return s; |
| |
| err: |
| up_write(&slub_lock); |
| if (flags & SLAB_PANIC) |
| panic("Cannot create slabcache %s\n", name); |
| else |
| s = NULL; |
| return s; |
| } |
| EXPORT_SYMBOL(kmem_cache_create); |
| |
| void *kmem_cache_zalloc(struct kmem_cache *s, gfp_t flags) |
| { |
| void *x; |
| |
| x = slab_alloc(s, flags, -1, __builtin_return_address(0)); |
| if (x) |
| memset(x, 0, s->objsize); |
| return x; |
| } |
| EXPORT_SYMBOL(kmem_cache_zalloc); |
| |
| #ifdef CONFIG_SMP |
| /* |
| * Use the cpu notifier to insure that the cpu slabs are flushed when |
| * necessary. |
| */ |
| static int __cpuinit slab_cpuup_callback(struct notifier_block *nfb, |
| unsigned long action, void *hcpu) |
| { |
| long cpu = (long)hcpu; |
| struct kmem_cache *s; |
| unsigned long flags; |
| |
| switch (action) { |
| case CPU_UP_CANCELED: |
| case CPU_UP_CANCELED_FROZEN: |
| case CPU_DEAD: |
| case CPU_DEAD_FROZEN: |
| down_read(&slub_lock); |
| list_for_each_entry(s, &slab_caches, list) { |
| local_irq_save(flags); |
| __flush_cpu_slab(s, cpu); |
| local_irq_restore(flags); |
| } |
| up_read(&slub_lock); |
| break; |
| default: |
| break; |
| } |
| return NOTIFY_OK; |
| } |
| |
| static struct notifier_block __cpuinitdata slab_notifier = |
| { &slab_cpuup_callback, NULL, 0 }; |
| |
| #endif |
| |
| void *__kmalloc_track_caller(size_t size, gfp_t gfpflags, void *caller) |
| { |
| struct kmem_cache *s = get_slab(size, gfpflags); |
| |
| if (!s) |
| return ZERO_SIZE_PTR; |
| |
| return slab_alloc(s, gfpflags, -1, caller); |
| } |
| |
| void *__kmalloc_node_track_caller(size_t size, gfp_t gfpflags, |
| int node, void *caller) |
| { |
| struct kmem_cache *s = get_slab(size, gfpflags); |
| |
| if (!s) |
| return ZERO_SIZE_PTR; |
| |
| return slab_alloc(s, gfpflags, node, caller); |
| } |
| |
| #if defined(CONFIG_SYSFS) && defined(CONFIG_SLUB_DEBUG) |
| static int validate_slab(struct kmem_cache *s, struct page *page) |
| { |
| void *p; |
| void *addr = page_address(page); |
| DECLARE_BITMAP(map, s->objects); |
| |
| if (!check_slab(s, page) || |
| !on_freelist(s, page, NULL)) |
| return 0; |
| |
| /* Now we know that a valid freelist exists */ |
| bitmap_zero(map, s->objects); |
| |
| for_each_free_object(p, s, page->freelist) { |
| set_bit(slab_index(p, s, addr), map); |
| if (!check_object(s, page, p, 0)) |
| return 0; |
| } |
| |
| for_each_object(p, s, addr) |
| if (!test_bit(slab_index(p, s, addr), map)) |
| if (!check_object(s, page, p, 1)) |
| return 0; |
| return 1; |
| } |
| |
| static void validate_slab_slab(struct kmem_cache *s, struct page *page) |
| { |
| if (slab_trylock(page)) { |
| validate_slab(s, page); |
| slab_unlock(page); |
| } else |
| printk(KERN_INFO "SLUB %s: Skipped busy slab 0x%p\n", |
| s->name, page); |
| |
| if (s->flags & DEBUG_DEFAULT_FLAGS) { |
| if (!SlabDebug(page)) |
| printk(KERN_ERR "SLUB %s: SlabDebug not set " |
| "on slab 0x%p\n", s->name, page); |
| } else { |
| if (SlabDebug(page)) |
| printk(KERN_ERR "SLUB %s: SlabDebug set on " |
| "slab 0x%p\n", s->name, page); |
| } |
| } |
| |
| static int validate_slab_node(struct kmem_cache *s, struct kmem_cache_node *n) |
| { |
| unsigned long count = 0; |
| struct page *page; |
| unsigned long flags; |
| |
| spin_lock_irqsave(&n->list_lock, flags); |
| |
| list_for_each_entry(page, &n->partial, lru) { |
| validate_slab_slab(s, page); |
| count++; |
| } |
| if (count != n->nr_partial) |
| printk(KERN_ERR "SLUB %s: %ld partial slabs counted but " |
| "counter=%ld\n", s->name, count, n->nr_partial); |
| |
| if (!(s->flags & SLAB_STORE_USER)) |
| goto out; |
| |
| list_for_each_entry(page, &n->full, lru) { |
| validate_slab_slab(s, page); |
| count++; |
| } |
| if (count != atomic_long_read(&n->nr_slabs)) |
| printk(KERN_ERR "SLUB: %s %ld slabs counted but " |
| "counter=%ld\n", s->name, count, |
| atomic_long_read(&n->nr_slabs)); |
| |
| out: |
| spin_unlock_irqrestore(&n->list_lock, flags); |
| return count; |
| } |
| |
| static unsigned long validate_slab_cache(struct kmem_cache *s) |
| { |
| int node; |
| unsigned long count = 0; |
| |
| flush_all(s); |
| for_each_online_node(node) { |
| struct kmem_cache_node *n = get_node(s, node); |
| |
| count += validate_slab_node(s, n); |
| } |
| return count; |
| } |
| |
| #ifdef SLUB_RESILIENCY_TEST |
| static void resiliency_test(void) |
| { |
| u8 *p; |
| |
| printk(KERN_ERR "SLUB resiliency testing\n"); |
| printk(KERN_ERR "-----------------------\n"); |
| printk(KERN_ERR "A. Corruption after allocation\n"); |
| |
| p = kzalloc(16, GFP_KERNEL); |
| p[16] = 0x12; |
| printk(KERN_ERR "\n1. kmalloc-16: Clobber Redzone/next pointer" |
| " 0x12->0x%p\n\n", p + 16); |
| |
| validate_slab_cache(kmalloc_caches + 4); |
| |
| /* Hmmm... The next two are dangerous */ |
| p = kzalloc(32, GFP_KERNEL); |
| p[32 + sizeof(void *)] = 0x34; |
| printk(KERN_ERR "\n2. kmalloc-32: Clobber next pointer/next slab" |
| " 0x34 -> -0x%p\n", p); |
| printk(KERN_ERR "If allocated object is overwritten then not detectable\n\n"); |
| |
| validate_slab_cache(kmalloc_caches + 5); |
| p = kzalloc(64, GFP_KERNEL); |
| p += 64 + (get_cycles() & 0xff) * sizeof(void *); |
| *p = 0x56; |
| printk(KERN_ERR "\n3. kmalloc-64: corrupting random byte 0x56->0x%p\n", |
| p); |
| printk(KERN_ERR "If allocated object is overwritten then not detectable\n\n"); |
| validate_slab_cache(kmalloc_caches + 6); |
| |
| printk(KERN_ERR "\nB. Corruption after free\n"); |
| p = kzalloc(128, GFP_KERNEL); |
| kfree(p); |
| *p = 0x78; |
| printk(KERN_ERR "1. kmalloc-128: Clobber first word 0x78->0x%p\n\n", p); |
| validate_slab_cache(kmalloc_caches + 7); |
| |
| p = kzalloc(256, GFP_KERNEL); |
| kfree(p); |
| p[50] = 0x9a; |
| printk(KERN_ERR "\n2. kmalloc-256: Clobber 50th byte 0x9a->0x%p\n\n", p); |
| validate_slab_cache(kmalloc_caches + 8); |
| |
| p = kzalloc(512, GFP_KERNEL); |
| kfree(p); |
| p[512] = 0xab; |
| printk(KERN_ERR "\n3. kmalloc-512: Clobber redzone 0xab->0x%p\n\n", p); |
| validate_slab_cache(kmalloc_caches + 9); |
| } |
| #else |
| static void resiliency_test(void) {}; |
| #endif |
| |
| /* |
| * Generate lists of code addresses where slabcache objects are allocated |
| * and freed. |
| */ |
| |
| struct location { |
| unsigned long count; |
| void *addr; |
| long long sum_time; |
| long min_time; |
| long max_time; |
| long min_pid; |
| long max_pid; |
| cpumask_t cpus; |
| nodemask_t nodes; |
| }; |
| |
| struct loc_track { |
| unsigned long max; |
| unsigned long count; |
| struct location *loc; |
| }; |
| |
| static void free_loc_track(struct loc_track *t) |
| { |
| if (t->max) |
| free_pages((unsigned long)t->loc, |
| get_order(sizeof(struct location) * t->max)); |
| } |
| |
| static int alloc_loc_track(struct loc_track *t, unsigned long max, gfp_t flags) |
| { |
| struct location *l; |
| int order; |
| |
| order = get_order(sizeof(struct location) * max); |
| |
| l = (void *)__get_free_pages(flags, order); |
| if (!l) |
| return 0; |
| |
| if (t->count) { |
| memcpy(l, t->loc, sizeof(struct location) * t->count); |
| free_loc_track(t); |
| } |
| t->max = max; |
| t->loc = l; |
| return 1; |
| } |
| |
| static int add_location(struct loc_track *t, struct kmem_cache *s, |
| const struct track *track) |
| { |
| long start, end, pos; |
| struct location *l; |
| void *caddr; |
| unsigned long age = jiffies - track->when; |
| |
| start = -1; |
| end = t->count; |
| |
| for ( ; ; ) { |
| pos = start + (end - start + 1) / 2; |
| |
| /* |
| * There is nothing at "end". If we end up there |
| * we need to add something to before end. |
| */ |
| if (pos == end) |
| break; |
| |
| caddr = t->loc[pos].addr; |
| if (track->addr == caddr) { |
| |
| l = &t->loc[pos]; |
| l->count++; |
| if (track->when) { |
| l->sum_time += age; |
| if (age < l->min_time) |
| l->min_time = age; |
| if (age > l->max_time) |
| l->max_time = age; |
| |
| if (track->pid < l->min_pid) |
| l->min_pid = track->pid; |
| if (track->pid > l->max_pid) |
| l->max_pid = track->pid; |
| |
| cpu_set(track->cpu, l->cpus); |
| } |
| node_set(page_to_nid(virt_to_page(track)), l->nodes); |
| return 1; |
| } |
| |
| if (track->addr < caddr) |
| end = pos; |
| else |
| start = pos; |
| } |
| |
| /* |
| * Not found. Insert new tracking element. |
| */ |
| if (t->count >= t->max && !alloc_loc_track(t, 2 * t->max, GFP_ATOMIC)) |
| return 0; |
| |
| l = t->loc + pos; |
| if (pos < t->count) |
| memmove(l + 1, l, |
| (t->count - pos) * sizeof(struct location)); |
| t->count++; |
| l->count = 1; |
| l->addr = track->addr; |
| l->sum_time = age; |
| l->min_time = age; |
| l->max_time = age; |
| l->min_pid = track->pid; |
| l->max_pid = track->pid; |
| cpus_clear(l->cpus); |
| cpu_set(track->cpu, l->cpus); |
| nodes_clear(l->nodes); |
| node_set(page_to_nid(virt_to_page(track)), l->nodes); |
| return 1; |
| } |
| |
| static void process_slab(struct loc_track *t, struct kmem_cache *s, |
| struct page *page, enum track_item alloc) |
| { |
| void *addr = page_address(page); |
| DECLARE_BITMAP(map, s->objects); |
| void *p; |
| |
| bitmap_zero(map, s->objects); |
| for_each_free_object(p, s, page->freelist) |
| set_bit(slab_index(p, s, addr), map); |
| |
| for_each_object(p, s, addr) |
| if (!test_bit(slab_index(p, s, addr), map)) |
| add_location(t, s, get_track(s, p, alloc)); |
| } |
| |
| static int list_locations(struct kmem_cache *s, char *buf, |
| enum track_item alloc) |
| { |
| int n = 0; |
| unsigned long i; |
| struct loc_track t = { 0, 0, NULL }; |
| int node; |
| |
| if (!alloc_loc_track(&t, PAGE_SIZE / sizeof(struct location), |
| GFP_KERNEL)) |
| return sprintf(buf, "Out of memory\n"); |
| |
| /* Push back cpu slabs */ |
| flush_all(s); |
| |
| for_each_online_node(node) { |
| struct kmem_cache_node *n = get_node(s, node); |
| unsigned long flags; |
| struct page *page; |
| |
| if (!atomic_read(&n->nr_slabs)) |
| continue; |
| |
| spin_lock_irqsave(&n->list_lock, flags); |
| list_for_each_entry(page, &n->partial, lru) |
| process_slab(&t, s, page, alloc); |
| list_for_each_entry(page, &n->full, lru) |
| process_slab(&t, s, page, alloc); |
| spin_unlock_irqrestore(&n->list_lock, flags); |
| } |
| |
| for (i = 0; i < t.count; i++) { |
| struct location *l = &t.loc[i]; |
| |
| if (n > PAGE_SIZE - 100) |
| break; |
| n += sprintf(buf + n, "%7ld ", l->count); |
| |
| if (l->addr) |
| n += sprint_symbol(buf + n, (unsigned long)l->addr); |
| else |
| n += sprintf(buf + n, "<not-available>"); |
| |
| if (l->sum_time != l->min_time) { |
| unsigned long remainder; |
| |
| n += sprintf(buf + n, " age=%ld/%ld/%ld", |
| l->min_time, |
| div_long_long_rem(l->sum_time, l->count, &remainder), |
| l->max_time); |
| } else |
| n += sprintf(buf + n, " age=%ld", |
| l->min_time); |
| |
| if (l->min_pid != l->max_pid) |
| n += sprintf(buf + n, " pid=%ld-%ld", |
| l->min_pid, l->max_pid); |
| else |
| n += sprintf(buf + n, " pid=%ld", |
| l->min_pid); |
| |
| if (num_online_cpus() > 1 && !cpus_empty(l->cpus) && |
| n < PAGE_SIZE - 60) { |
| n += sprintf(buf + n, " cpus="); |
| n += cpulist_scnprintf(buf + n, PAGE_SIZE - n - 50, |
| l->cpus); |
| } |
| |
| if (num_online_nodes() > 1 && !nodes_empty(l->nodes) && |
| n < PAGE_SIZE - 60) { |
| n += sprintf(buf + n, " nodes="); |
| n += nodelist_scnprintf(buf + n, PAGE_SIZE - n - 50, |
| l->nodes); |
| } |
| |
| n += sprintf(buf + n, "\n"); |
| } |
| |
| free_loc_track(&t); |
| if (!t.count) |
| n += sprintf(buf, "No data\n"); |
| return n; |
| } |
| |
| static unsigned long count_partial(struct kmem_cache_node *n) |
| { |
| unsigned long flags; |
| unsigned long x = 0; |
| struct page *page; |
| |
| spin_lock_irqsave(&n->list_lock, flags); |
| list_for_each_entry(page, &n->partial, lru) |
| x += page->inuse; |
| spin_unlock_irqrestore(&n->list_lock, flags); |
| return x; |
| } |
| |
| enum slab_stat_type { |
| SL_FULL, |
| SL_PARTIAL, |
| SL_CPU, |
| SL_OBJECTS |
| }; |
| |
| #define SO_FULL (1 << SL_FULL) |
| #define SO_PARTIAL (1 << SL_PARTIAL) |
| #define SO_CPU (1 << SL_CPU) |
| #define SO_OBJECTS (1 << SL_OBJECTS) |
| |
| static unsigned long slab_objects(struct kmem_cache *s, |
| char *buf, unsigned long flags) |
| { |
| unsigned long total = 0; |
| int cpu; |
| int node; |
| int x; |
| unsigned long *nodes; |
| unsigned long *per_cpu; |
| |
| nodes = kzalloc(2 * sizeof(unsigned long) * nr_node_ids, GFP_KERNEL); |
| per_cpu = nodes + nr_node_ids; |
| |
| for_each_possible_cpu(cpu) { |
| struct page *page = s->cpu_slab[cpu]; |
| int node; |
| |
| if (page) { |
| node = page_to_nid(page); |
| if (flags & SO_CPU) { |
| int x = 0; |
| |
| if (flags & SO_OBJECTS) |
| x = page->inuse; |
| else |
| x = 1; |
| total += x; |
| nodes[node] += x; |
| } |
| per_cpu[node]++; |
| } |
| } |
| |
| for_each_online_node(node) { |
| struct kmem_cache_node *n = get_node(s, node); |
| |
| if (flags & SO_PARTIAL) { |
| if (flags & SO_OBJECTS) |
| x = count_partial(n); |
| else |
| x = n->nr_partial; |
| total += x; |
| nodes[node] += x; |
| } |
| |
| if (flags & SO_FULL) { |
| int full_slabs = atomic_read(&n->nr_slabs) |
| - per_cpu[node] |
| - n->nr_partial; |
| |
| if (flags & SO_OBJECTS) |
| x = full_slabs * s->objects; |
| else |
| x = full_slabs; |
| total += x; |
| nodes[node] += x; |
| } |
| } |
| |
| x = sprintf(buf, "%lu", total); |
| #ifdef CONFIG_NUMA |
| for_each_online_node(node) |
| if (nodes[node]) |
| x += sprintf(buf + x, " N%d=%lu", |
| node, nodes[node]); |
| #endif |
| kfree(nodes); |
| return x + sprintf(buf + x, "\n"); |
| } |
| |
| static int any_slab_objects(struct kmem_cache *s) |
| { |
| int node; |
| int cpu; |
| |
| for_each_possible_cpu(cpu) |
| if (s->cpu_slab[cpu]) |
| return 1; |
| |
| for_each_node(node) { |
| struct kmem_cache_node *n = get_node(s, node); |
| |
| if (n->nr_partial || atomic_read(&n->nr_slabs)) |
| return 1; |
| } |
| return 0; |
| } |
| |
| #define to_slab_attr(n) container_of(n, struct slab_attribute, attr) |
| #define to_slab(n) container_of(n, struct kmem_cache, kobj); |
| |
| struct slab_attribute { |
| struct attribute attr; |
| ssize_t (*show)(struct kmem_cache *s, char *buf); |
| ssize_t (*store)(struct kmem_cache *s, const char *x, size_t count); |
| }; |
| |
| #define SLAB_ATTR_RO(_name) \ |
| static struct slab_attribute _name##_attr = __ATTR_RO(_name) |
| |
| #define SLAB_ATTR(_name) \ |
| static struct slab_attribute _name##_attr = \ |
| __ATTR(_name, 0644, _name##_show, _name##_store) |
| |
| static ssize_t slab_size_show(struct kmem_cache *s, char *buf) |
| { |
| return sprintf(buf, "%d\n", s->size); |
| } |
| SLAB_ATTR_RO(slab_size); |
| |
| static ssize_t align_show(struct kmem_cache *s, char *buf) |
| { |
| return sprintf(buf, "%d\n", s->align); |
| } |
| SLAB_ATTR_RO(align); |
| |
| static ssize_t object_size_show(struct kmem_cache *s, char *buf) |
| { |
| return sprintf(buf, "%d\n", s->objsize); |
| } |
| SLAB_ATTR_RO(object_size); |
| |
| static ssize_t objs_per_slab_show(struct kmem_cache *s, char *buf) |
| { |
| return sprintf(buf, "%d\n", s->objects); |
| } |
| SLAB_ATTR_RO(objs_per_slab); |
| |
| static ssize_t order_show(struct kmem_cache *s, char *buf) |
| { |
| return sprintf(buf, "%d\n", s->order); |
| } |
| SLAB_ATTR_RO(order); |
| |
| static ssize_t ctor_show(struct kmem_cache *s, char *buf) |
| { |
| if (s->ctor) { |
| int n = sprint_symbol(buf, (unsigned long)s->ctor); |
| |
| return n + sprintf(buf + n, "\n"); |
| } |
| return 0; |
| } |
| SLAB_ATTR_RO(ctor); |
| |
| static ssize_t aliases_show(struct kmem_cache *s, char *buf) |
| { |
| return sprintf(buf, "%d\n", s->refcount - 1); |
| } |
| SLAB_ATTR_RO(aliases); |
| |
| static ssize_t slabs_show(struct kmem_cache *s, char *buf) |
| { |
| return slab_objects(s, buf, SO_FULL|SO_PARTIAL|SO_CPU); |
| } |
| SLAB_ATTR_RO(slabs); |
| |
| static ssize_t partial_show(struct kmem_cache *s, char *buf) |
| { |
| return slab_objects(s, buf, SO_PARTIAL); |
| } |
| SLAB_ATTR_RO(partial); |
| |
| static ssize_t cpu_slabs_show(struct kmem_cache *s, char *buf) |
| { |
| return slab_objects(s, buf, SO_CPU); |
| } |
| SLAB_ATTR_RO(cpu_slabs); |
| |
| static ssize_t objects_show(struct kmem_cache *s, char *buf) |
| { |
| return slab_objects(s, buf, SO_FULL|SO_PARTIAL|SO_CPU|SO_OBJECTS); |
| } |
| SLAB_ATTR_RO(objects); |
| |
| static ssize_t sanity_checks_show(struct kmem_cache *s, char *buf) |
| { |
| return sprintf(buf, "%d\n", !!(s->flags & SLAB_DEBUG_FREE)); |
| } |
| |
| static ssize_t sanity_checks_store(struct kmem_cache *s, |
| const char *buf, size_t length) |
| { |
| s->flags &= ~SLAB_DEBUG_FREE; |
| if (buf[0] == '1') |
| s->flags |= SLAB_DEBUG_FREE; |
| return length; |
| } |
| SLAB_ATTR(sanity_checks); |
| |
| static ssize_t trace_show(struct kmem_cache *s, char *buf) |
| { |
| return sprintf(buf, "%d\n", !!(s->flags & SLAB_TRACE)); |
| } |
| |
| static ssize_t trace_store(struct kmem_cache *s, const char *buf, |
| size_t length) |
| { |
| s->flags &= ~SLAB_TRACE; |
| if (buf[0] == '1') |
| s->flags |= SLAB_TRACE; |
| return length; |
| } |
| SLAB_ATTR(trace); |
| |
| static ssize_t reclaim_account_show(struct kmem_cache *s, char *buf) |
| { |
| return sprintf(buf, "%d\n", !!(s->flags & SLAB_RECLAIM_ACCOUNT)); |
| } |
| |
| static ssize_t reclaim_account_store(struct kmem_cache *s, |
| const char *buf, size_t length) |
| { |
| s->flags &= ~SLAB_RECLAIM_ACCOUNT; |
| if (buf[0] == '1') |
| s->flags |= SLAB_RECLAIM_ACCOUNT; |
| return length; |
| } |
| SLAB_ATTR(reclaim_account); |
| |
| static ssize_t hwcache_align_show(struct kmem_cache *s, char *buf) |
| { |
| return sprintf(buf, "%d\n", !!(s->flags & SLAB_HWCACHE_ALIGN)); |
| } |
| SLAB_ATTR_RO(hwcache_align); |
| |
| #ifdef CONFIG_ZONE_DMA |
| static ssize_t cache_dma_show(struct kmem_cache *s, char *buf) |
| { |
| return sprintf(buf, "%d\n", !!(s->flags & SLAB_CACHE_DMA)); |
| } |
| SLAB_ATTR_RO(cache_dma); |
| #endif |
| |
| static ssize_t destroy_by_rcu_show(struct kmem_cache *s, char *buf) |
| { |
| return sprintf(buf, "%d\n", !!(s->flags & SLAB_DESTROY_BY_RCU)); |
| } |
| SLAB_ATTR_RO(destroy_by_rcu); |
| |
| static ssize_t red_zone_show(struct kmem_cache *s, char *buf) |
| { |
| return sprintf(buf, "%d\n", !!(s->flags & SLAB_RED_ZONE)); |
| } |
| |
| static ssize_t red_zone_store(struct kmem_cache *s, |
| const char *buf, size_t length) |
| { |
| if (any_slab_objects(s)) |
| return -EBUSY; |
| |
| s->flags &= ~SLAB_RED_ZONE; |
| if (buf[0] == '1') |
| s->flags |= SLAB_RED_ZONE; |
| calculate_sizes(s); |
| return length; |
| } |
| SLAB_ATTR(red_zone); |
| |
| static ssize_t poison_show(struct kmem_cache *s, char *buf) |
| { |
| return sprintf(buf, "%d\n", !!(s->flags & SLAB_POISON)); |
| } |
| |
| static ssize_t poison_store(struct kmem_cache *s, |
| const char *buf, size_t length) |
| { |
| if (any_slab_objects(s)) |
| return -EBUSY; |
| |
| s->flags &= ~SLAB_POISON; |
| if (buf[0] == '1') |
| s->flags |= SLAB_POISON; |
| calculate_sizes(s); |
| return length; |
| } |
| SLAB_ATTR(poison); |
| |
| static ssize_t store_user_show(struct kmem_cache *s, char *buf) |
| { |
| return sprintf(buf, "%d\n", !!(s->flags & SLAB_STORE_USER)); |
| } |
| |
| static ssize_t store_user_store(struct kmem_cache *s, |
| const char *buf, size_t length) |
| { |
| if (any_slab_objects(s)) |
| return -EBUSY; |
| |
| s->flags &= ~SLAB_STORE_USER; |
| if (buf[0] == '1') |
| s->flags |= SLAB_STORE_USER; |
| calculate_sizes(s); |
| return length; |
| } |
| SLAB_ATTR(store_user); |
| |
| static ssize_t validate_show(struct kmem_cache *s, char *buf) |
| { |
| return 0; |
| } |
| |
| static ssize_t validate_store(struct kmem_cache *s, |
| const char *buf, size_t length) |
| { |
| if (buf[0] == '1') |
| validate_slab_cache(s); |
| else |
| return -EINVAL; |
| return length; |
| } |
| SLAB_ATTR(validate); |
| |
| static ssize_t shrink_show(struct kmem_cache *s, char *buf) |
| { |
| return 0; |
| } |
| |
| static ssize_t shrink_store(struct kmem_cache *s, |
| const char *buf, size_t length) |
| { |
| if (buf[0] == '1') { |
| int rc = kmem_cache_shrink(s); |
| |
| if (rc) |
| return rc; |
| } else |
| return -EINVAL; |
| return length; |
| } |
| SLAB_ATTR(shrink); |
| |
| static ssize_t alloc_calls_show(struct kmem_cache *s, char *buf) |
| { |
| if (!(s->flags & SLAB_STORE_USER)) |
| return -ENOSYS; |
| return list_locations(s, buf, TRACK_ALLOC); |
| } |
| SLAB_ATTR_RO(alloc_calls); |
| |
| static ssize_t free_calls_show(struct kmem_cache *s, char *buf) |
| { |
| if (!(s->flags & SLAB_STORE_USER)) |
| return -ENOSYS; |
| return list_locations(s, buf, TRACK_FREE); |
| } |
| SLAB_ATTR_RO(free_calls); |
| |
| #ifdef CONFIG_NUMA |
| static ssize_t defrag_ratio_show(struct kmem_cache *s, char *buf) |
| { |
| return sprintf(buf, "%d\n", s->defrag_ratio / 10); |
| } |
| |
| static ssize_t defrag_ratio_store(struct kmem_cache *s, |
| const char *buf, size_t length) |
| { |
| int n = simple_strtoul(buf, NULL, 10); |
| |
| if (n < 100) |
| s->defrag_ratio = n * 10; |
| return length; |
| } |
| SLAB_ATTR(defrag_ratio); |
| #endif |
| |
| static struct attribute * slab_attrs[] = { |
| &slab_size_attr.attr, |
| &object_size_attr.attr, |
| &objs_per_slab_attr.attr, |
| &order_attr.attr, |
| &objects_attr.attr, |
| &slabs_attr.attr, |
| &partial_attr.attr, |
| &cpu_slabs_attr.attr, |
| &ctor_attr.attr, |
| &aliases_attr.attr, |
| &align_attr.attr, |
| &sanity_checks_attr.attr, |
| &trace_attr.attr, |
| &hwcache_align_attr.attr, |
| &reclaim_account_attr.attr, |
| &destroy_by_rcu_attr.attr, |
| &red_zone_attr.attr, |
| &poison_attr.attr, |
| &store_user_attr.attr, |
| &validate_attr.attr, |
| &shrink_attr.attr, |
| &alloc_calls_attr.attr, |
| &free_calls_attr.attr, |
| #ifdef CONFIG_ZONE_DMA |
| &cache_dma_attr.attr, |
| #endif |
| #ifdef CONFIG_NUMA |
| &defrag_ratio_attr.attr, |
| #endif |
| NULL |
| }; |
| |
| static struct attribute_group slab_attr_group = { |
| .attrs = slab_attrs, |
| }; |
| |
| static ssize_t slab_attr_show(struct kobject *kobj, |
| struct attribute *attr, |
| char *buf) |
| { |
| struct slab_attribute *attribute; |
| struct kmem_cache *s; |
| int err; |
| |
| attribute = to_slab_attr(attr); |
| s = to_slab(kobj); |
| |
| if (!attribute->show) |
| return -EIO; |
| |
| err = attribute->show(s, buf); |
| |
| return err; |
| } |
| |
| static ssize_t slab_attr_store(struct kobject *kobj, |
| struct attribute *attr, |
| const char *buf, size_t len) |
| { |
| struct slab_attribute *attribute; |
| struct kmem_cache *s; |
| int err; |
| |
| attribute = to_slab_attr(attr); |
| s = to_slab(kobj); |
| |
| if (!attribute->store) |
| return -EIO; |
| |
| err = attribute->store(s, buf, len); |
| |
| return err; |
| } |
| |
| static struct sysfs_ops slab_sysfs_ops = { |
| .show = slab_attr_show, |
| .store = slab_attr_store, |
| }; |
| |
| static struct kobj_type slab_ktype = { |
| .sysfs_ops = &slab_sysfs_ops, |
| }; |
| |
| static int uevent_filter(struct kset *kset, struct kobject *kobj) |
| { |
| struct kobj_type *ktype = get_ktype(kobj); |
| |
| if (ktype == &slab_ktype) |
| return 1; |
| return 0; |
| } |
| |
| static struct kset_uevent_ops slab_uevent_ops = { |
| .filter = uevent_filter, |
| }; |
| |
| decl_subsys(slab, &slab_ktype, &slab_uevent_ops); |
| |
| #define ID_STR_LENGTH 64 |
| |
| /* Create a unique string id for a slab cache: |
| * format |
| * :[flags-]size:[memory address of kmemcache] |
| */ |
| static char *create_unique_id(struct kmem_cache *s) |
| { |
| char *name = kmalloc(ID_STR_LENGTH, GFP_KERNEL); |
| char *p = name; |
| |
| BUG_ON(!name); |
| |
| *p++ = ':'; |
| /* |
| * First flags affecting slabcache operations. We will only |
| * get here for aliasable slabs so we do not need to support |
| * too many flags. The flags here must cover all flags that |
| * are matched during merging to guarantee that the id is |
| * unique. |
| */ |
| if (s->flags & SLAB_CACHE_DMA) |
| *p++ = 'd'; |
| if (s->flags & SLAB_RECLAIM_ACCOUNT) |
| *p++ = 'a'; |
| if (s->flags & SLAB_DEBUG_FREE) |
| *p++ = 'F'; |
| if (p != name + 1) |
| *p++ = '-'; |
| p += sprintf(p, "%07d", s->size); |
| BUG_ON(p > name + ID_STR_LENGTH - 1); |
| return name; |
| } |
| |
| static int sysfs_slab_add(struct kmem_cache *s) |
| { |
| int err; |
| const char *name; |
| int unmergeable; |
| |
| if (slab_state < SYSFS) |
| /* Defer until later */ |
| return 0; |
| |
| unmergeable = slab_unmergeable(s); |
| if (unmergeable) { |
| /* |
| * Slabcache can never be merged so we can use the name proper. |
| * This is typically the case for debug situations. In that |
| * case we can catch duplicate names easily. |
| */ |
| sysfs_remove_link(&slab_subsys.kobj, s->name); |
| name = s->name; |
| } else { |
| /* |
| * Create a unique name for the slab as a target |
| * for the symlinks. |
| */ |
| name = create_unique_id(s); |
| } |
| |
| kobj_set_kset_s(s, slab_subsys); |
| kobject_set_name(&s->kobj, name); |
| kobject_init(&s->kobj); |
| err = kobject_add(&s->kobj); |
| if (err) |
| return err; |
| |
| err = sysfs_create_group(&s->kobj, &slab_attr_group); |
| if (err) |
| return err; |
| kobject_uevent(&s->kobj, KOBJ_ADD); |
| if (!unmergeable) { |
| /* Setup first alias */ |
| sysfs_slab_alias(s, s->name); |
| kfree(name); |
| } |
| return 0; |
| } |
| |
| static void sysfs_slab_remove(struct kmem_cache *s) |
| { |
| kobject_uevent(&s->kobj, KOBJ_REMOVE); |
| kobject_del(&s->kobj); |
| } |
| |
| /* |
| * Need to buffer aliases during bootup until sysfs becomes |
| * available lest we loose that information. |
| */ |
| struct saved_alias { |
| struct kmem_cache *s; |
| const char *name; |
| struct saved_alias *next; |
| }; |
| |
| struct saved_alias *alias_list; |
| |
| static int sysfs_slab_alias(struct kmem_cache *s, const char *name) |
| { |
| struct saved_alias *al; |
| |
| if (slab_state == SYSFS) { |
| /* |
| * If we have a leftover link then remove it. |
| */ |
| sysfs_remove_link(&slab_subsys.kobj, name); |
| return sysfs_create_link(&slab_subsys.kobj, |
| &s->kobj, name); |
| } |
| |
| al = kmalloc(sizeof(struct saved_alias), GFP_KERNEL); |
| if (!al) |
| return -ENOMEM; |
| |
| al->s = s; |
| al->name = name; |
| al->next = alias_list; |
| alias_list = al; |
| return 0; |
| } |
| |
| static int __init slab_sysfs_init(void) |
| { |
| struct kmem_cache *s; |
| int err; |
| |
| err = subsystem_register(&slab_subsys); |
| if (err) { |
| printk(KERN_ERR "Cannot register slab subsystem.\n"); |
| return -ENOSYS; |
| } |
| |
| slab_state = SYSFS; |
| |
| list_for_each_entry(s, &slab_caches, list) { |
| err = sysfs_slab_add(s); |
| BUG_ON(err); |
| } |
| |
| while (alias_list) { |
| struct saved_alias *al = alias_list; |
| |
| alias_list = alias_list->next; |
| err = sysfs_slab_alias(al->s, al->name); |
| BUG_ON(err); |
| kfree(al); |
| } |
| |
| resiliency_test(); |
| return 0; |
| } |
| |
| __initcall(slab_sysfs_init); |
| #endif |