| /* |
| * 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 or atomic operatios |
| * and only uses a centralized lock to manage a pool of partial slabs. |
| * |
| * (C) 2007 SGI, Christoph Lameter |
| * (C) 2011 Linux Foundation, Christoph Lameter |
| */ |
| |
| #include <linux/mm.h> |
| #include <linux/swap.h> /* struct reclaim_state */ |
| #include <linux/module.h> |
| #include <linux/bit_spinlock.h> |
| #include <linux/interrupt.h> |
| #include <linux/bitops.h> |
| #include <linux/slab.h> |
| #include <linux/proc_fs.h> |
| #include <linux/seq_file.h> |
| #include <linux/kmemcheck.h> |
| #include <linux/cpu.h> |
| #include <linux/cpuset.h> |
| #include <linux/mempolicy.h> |
| #include <linux/ctype.h> |
| #include <linux/debugobjects.h> |
| #include <linux/kallsyms.h> |
| #include <linux/memory.h> |
| #include <linux/math64.h> |
| #include <linux/fault-inject.h> |
| #include <linux/stacktrace.h> |
| |
| #include <trace/events/kmem.h> |
| |
| /* |
| * Lock order: |
| * 1. slub_lock (Global Semaphore) |
| * 2. node->list_lock |
| * 3. slab_lock(page) (Only on some arches and for debugging) |
| * |
| * slub_lock |
| * |
| * The role of the slub_lock is to protect the list of all the slabs |
| * and to synchronize major metadata changes to slab cache structures. |
| * |
| * The slab_lock is only used for debugging and on arches that do not |
| * have the ability to do a cmpxchg_double. It only protects the second |
| * double word in the page struct. Meaning |
| * A. page->freelist -> List of object free in a page |
| * B. page->counters -> Counters of objects |
| * C. page->frozen -> frozen state |
| * |
| * If a slab is frozen then it is exempt from list management. It is not |
| * on any list. The processor that froze the slab is the one who can |
| * perform list operations on the page. Other processors may put objects |
| * onto the freelist but the processor that froze the slab is the only |
| * one that can retrieve the objects from the page's freelist. |
| * |
| * 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. |
| * 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 |
| * 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 SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \ |
| SLAB_TRACE | SLAB_DEBUG_FREE) |
| |
| static inline int kmem_cache_debug(struct kmem_cache *s) |
| { |
| #ifdef CONFIG_SLUB_DEBUG |
| return unlikely(s->flags & SLAB_DEBUG_FLAGS); |
| #else |
| return 0; |
| #endif |
| } |
| |
| /* |
| * Issues still to be resolved: |
| * |
| * - 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 |
| |
| /* Enable to log cmpxchg failures */ |
| #undef SLUB_DEBUG_CMPXCHG |
| |
| /* |
| * 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 5 |
| |
| /* |
| * 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) |
| |
| /* |
| * Debugging flags that require metadata to be stored in the slab. These get |
| * disabled when slub_debug=O is used and a cache's min order increases with |
| * metadata. |
| */ |
| #define DEBUG_METADATA_FLAGS (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 | SLAB_NOLEAKTRACE | \ |
| SLAB_FAILSLAB) |
| |
| #define SLUB_MERGE_SAME (SLAB_DEBUG_FREE | SLAB_RECLAIM_ACCOUNT | \ |
| SLAB_CACHE_DMA | SLAB_NOTRACK) |
| |
| #define OO_SHIFT 16 |
| #define OO_MASK ((1 << OO_SHIFT) - 1) |
| #define MAX_OBJS_PER_PAGE 32767 /* since page.objects is u15 */ |
| |
| /* Internal SLUB flags */ |
| #define __OBJECT_POISON 0x80000000UL /* Poison object */ |
| #define __CMPXCHG_DOUBLE 0x40000000UL /* Use cmpxchg_double */ |
| |
| 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_node works */ |
| 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); |
| static LIST_HEAD(slab_caches); |
| |
| /* |
| * Tracking user of a slab. |
| */ |
| #define TRACK_ADDRS_COUNT 16 |
| struct track { |
| unsigned long addr; /* Called from address */ |
| #ifdef CONFIG_STACKTRACE |
| unsigned long addrs[TRACK_ADDRS_COUNT]; /* Called from address */ |
| #endif |
| 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 }; |
| |
| #ifdef CONFIG_SYSFS |
| 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 inline int sysfs_slab_add(struct kmem_cache *s) { return 0; } |
| static inline int sysfs_slab_alias(struct kmem_cache *s, const char *p) |
| { return 0; } |
| static inline void sysfs_slab_remove(struct kmem_cache *s) |
| { |
| kfree(s->name); |
| kfree(s); |
| } |
| |
| #endif |
| |
| static inline void stat(const struct kmem_cache *s, enum stat_item si) |
| { |
| #ifdef CONFIG_SLUB_STATS |
| __this_cpu_inc(s->cpu_slab->stat[si]); |
| #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) |
| { |
| return s->node[node]; |
| } |
| |
| /* Verify that a pointer has an address that is valid within a slab page */ |
| 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 + page->objects * s->size || |
| (object - base) % s->size) { |
| return 0; |
| } |
| |
| return 1; |
| } |
| |
| static inline void *get_freepointer(struct kmem_cache *s, void *object) |
| { |
| return *(void **)(object + s->offset); |
| } |
| |
| static inline void *get_freepointer_safe(struct kmem_cache *s, void *object) |
| { |
| void *p; |
| |
| #ifdef CONFIG_DEBUG_PAGEALLOC |
| probe_kernel_read(&p, (void **)(object + s->offset), sizeof(p)); |
| #else |
| p = get_freepointer(s, object); |
| #endif |
| return p; |
| } |
| |
| 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, __objects) \ |
| for (__p = (__addr); __p < (__addr) + (__objects) * (__s)->size;\ |
| __p += (__s)->size) |
| |
| /* 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; |
| } |
| |
| static inline size_t slab_ksize(const struct kmem_cache *s) |
| { |
| #ifdef CONFIG_SLUB_DEBUG |
| /* |
| * 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; |
| |
| #endif |
| /* |
| * 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; |
| } |
| |
| static inline int order_objects(int order, unsigned long size, int reserved) |
| { |
| return ((PAGE_SIZE << order) - reserved) / size; |
| } |
| |
| static inline struct kmem_cache_order_objects oo_make(int order, |
| unsigned long size, int reserved) |
| { |
| struct kmem_cache_order_objects x = { |
| (order << OO_SHIFT) + order_objects(order, size, reserved) |
| }; |
| |
| return x; |
| } |
| |
| static inline int oo_order(struct kmem_cache_order_objects x) |
| { |
| return x.x >> OO_SHIFT; |
| } |
| |
| static inline int oo_objects(struct kmem_cache_order_objects x) |
| { |
| return x.x & OO_MASK; |
| } |
| |
| /* |
| * 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); |
| } |
| |
| /* Interrupts must be disabled (for the fallback code to work right) */ |
| static inline bool __cmpxchg_double_slab(struct kmem_cache *s, struct page *page, |
| void *freelist_old, unsigned long counters_old, |
| void *freelist_new, unsigned long counters_new, |
| const char *n) |
| { |
| VM_BUG_ON(!irqs_disabled()); |
| #ifdef CONFIG_CMPXCHG_DOUBLE |
| if (s->flags & __CMPXCHG_DOUBLE) { |
| if (cmpxchg_double(&page->freelist, |
| freelist_old, counters_old, |
| freelist_new, counters_new)) |
| return 1; |
| } else |
| #endif |
| { |
| slab_lock(page); |
| if (page->freelist == freelist_old && page->counters == counters_old) { |
| page->freelist = freelist_new; |
| page->counters = counters_new; |
| slab_unlock(page); |
| return 1; |
| } |
| slab_unlock(page); |
| } |
| |
| cpu_relax(); |
| stat(s, CMPXCHG_DOUBLE_FAIL); |
| |
| #ifdef SLUB_DEBUG_CMPXCHG |
| printk(KERN_INFO "%s %s: cmpxchg double redo ", n, s->name); |
| #endif |
| |
| return 0; |
| } |
| |
| static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct page *page, |
| void *freelist_old, unsigned long counters_old, |
| void *freelist_new, unsigned long counters_new, |
| const char *n) |
| { |
| #ifdef CONFIG_CMPXCHG_DOUBLE |
| if (s->flags & __CMPXCHG_DOUBLE) { |
| if (cmpxchg_double(&page->freelist, |
| freelist_old, counters_old, |
| freelist_new, counters_new)) |
| return 1; |
| } else |
| #endif |
| { |
| unsigned long flags; |
| |
| local_irq_save(flags); |
| slab_lock(page); |
| if (page->freelist == freelist_old && page->counters == counters_old) { |
| page->freelist = freelist_new; |
| page->counters = counters_new; |
| slab_unlock(page); |
| local_irq_restore(flags); |
| return 1; |
| } |
| slab_unlock(page); |
| local_irq_restore(flags); |
| } |
| |
| cpu_relax(); |
| stat(s, CMPXCHG_DOUBLE_FAIL); |
| |
| #ifdef SLUB_DEBUG_CMPXCHG |
| printk(KERN_INFO "%s %s: cmpxchg double redo ", n, s->name); |
| #endif |
| |
| return 0; |
| } |
| |
| #ifdef CONFIG_SLUB_DEBUG |
| /* |
| * Determine a map of object in use on a page. |
| * |
| * Node listlock must be held to guarantee that the page does |
| * not vanish from under us. |
| */ |
| static void get_map(struct kmem_cache *s, struct page *page, unsigned long *map) |
| { |
| void *p; |
| void *addr = page_address(page); |
| |
| for (p = page->freelist; p; p = get_freepointer(s, p)) |
| set_bit(slab_index(p, s, addr), map); |
| } |
| |
| /* |
| * 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; |
| static int disable_higher_order_debug; |
| |
| /* |
| * Object debugging |
| */ |
| static void print_section(char *text, u8 *addr, unsigned int length) |
| { |
| print_hex_dump(KERN_ERR, text, DUMP_PREFIX_ADDRESS, 16, 1, addr, |
| length, 1); |
| } |
| |
| 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, unsigned long addr) |
| { |
| struct track *p = get_track(s, object, alloc); |
| |
| if (addr) { |
| #ifdef CONFIG_STACKTRACE |
| struct stack_trace trace; |
| int i; |
| |
| trace.nr_entries = 0; |
| trace.max_entries = TRACK_ADDRS_COUNT; |
| trace.entries = p->addrs; |
| trace.skip = 3; |
| save_stack_trace(&trace); |
| |
| /* See rant in lockdep.c */ |
| if (trace.nr_entries != 0 && |
| trace.entries[trace.nr_entries - 1] == ULONG_MAX) |
| trace.nr_entries--; |
| |
| for (i = trace.nr_entries; i < TRACK_ADDRS_COUNT; i++) |
| p->addrs[i] = 0; |
| #endif |
| p->addr = addr; |
| p->cpu = smp_processor_id(); |
| p->pid = current->pid; |
| 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, 0UL); |
| set_track(s, object, TRACK_ALLOC, 0UL); |
| } |
| |
| static void print_track(const char *s, struct track *t) |
| { |
| if (!t->addr) |
| return; |
| |
| printk(KERN_ERR "INFO: %s in %pS age=%lu cpu=%u pid=%d\n", |
| s, (void *)t->addr, jiffies - t->when, t->cpu, t->pid); |
| #ifdef CONFIG_STACKTRACE |
| { |
| int i; |
| for (i = 0; i < TRACK_ADDRS_COUNT; i++) |
| if (t->addrs[i]) |
| printk(KERN_ERR "\t%pS\n", (void *)t->addrs[i]); |
| else |
| break; |
| } |
| #endif |
| } |
| |
| 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 objects=%u used=%u fp=0x%p flags=0x%04lx\n", |
| page, page->objects, 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_t(unsigned long, s->objsize, |
| PAGE_SIZE)); |
| 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, "%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, "%s", buf); |
| print_page_info(page); |
| dump_stack(); |
| } |
| |
| static void init_object(struct kmem_cache *s, void *object, u8 val) |
| { |
| 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, val, s->inuse - s->objsize); |
| } |
| |
| 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 = memchr_inv(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 debugging 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); |
| } |
| |
| /* Check the pad bytes at the end of a slab page */ |
| 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); |
| length = (PAGE_SIZE << compound_order(page)) - s->reserved; |
| end = start + length; |
| remainder = length % s->size; |
| if (!remainder) |
| return 1; |
| |
| fault = memchr_inv(end - remainder, 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 ", end - remainder, remainder); |
| |
| restore_bytes(s, "slab padding", POISON_INUSE, end - remainder, end); |
| return 0; |
| } |
| |
| static int check_object(struct kmem_cache *s, struct page *page, |
| void *object, u8 val) |
| { |
| u8 *p = object; |
| u8 *endobject = object + s->objsize; |
| |
| if (s->flags & SLAB_RED_ZONE) { |
| if (!check_bytes_and_report(s, page, object, "Redzone", |
| endobject, val, 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 (val != SLUB_RED_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 && val == SLUB_RED_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 lose 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) |
| { |
| int maxobj; |
| |
| VM_BUG_ON(!irqs_disabled()); |
| |
| if (!PageSlab(page)) { |
| slab_err(s, page, "Not a valid slab page"); |
| return 0; |
| } |
| |
| maxobj = order_objects(compound_order(page), s->size, s->reserved); |
| if (page->objects > maxobj) { |
| slab_err(s, page, "objects %u > max %u", |
| s->name, page->objects, maxobj); |
| return 0; |
| } |
| if (page->inuse > page->objects) { |
| slab_err(s, page, "inuse %u > max %u", |
| s->name, page->inuse, page->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; |
| void *object = NULL; |
| unsigned long max_objects; |
| |
| fp = page->freelist; |
| while (fp && nr <= page->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 = page->objects; |
| slab_fix(s, "Freelist cleared"); |
| return 0; |
| } |
| break; |
| } |
| object = fp; |
| fp = get_freepointer(s, object); |
| nr++; |
| } |
| |
| max_objects = order_objects(compound_order(page), s->size, s->reserved); |
| if (max_objects > MAX_OBJS_PER_PAGE) |
| max_objects = MAX_OBJS_PER_PAGE; |
| |
| if (page->objects != max_objects) { |
| slab_err(s, page, "Wrong number of objects. Found %d but " |
| "should be %d", page->objects, max_objects); |
| page->objects = max_objects; |
| slab_fix(s, "Number of objects adjusted."); |
| } |
| if (page->inuse != page->objects - nr) { |
| slab_err(s, page, "Wrong object count. Counter is %d but " |
| "counted were %d", page->inuse, page->objects - nr); |
| page->inuse = page->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(); |
| } |
| } |
| |
| /* |
| * Hooks for other subsystems that check memory allocations. In a typical |
| * production configuration these hooks all should produce no code at all. |
| */ |
| static inline int slab_pre_alloc_hook(struct kmem_cache *s, gfp_t flags) |
| { |
| flags &= gfp_allowed_mask; |
| lockdep_trace_alloc(flags); |
| might_sleep_if(flags & __GFP_WAIT); |
| |
| return should_failslab(s->objsize, flags, s->flags); |
| } |
| |
| static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags, void *object) |
| { |
| flags &= gfp_allowed_mask; |
| kmemcheck_slab_alloc(s, flags, object, slab_ksize(s)); |
| kmemleak_alloc_recursive(object, s->objsize, 1, s->flags, flags); |
| } |
| |
| static inline void slab_free_hook(struct kmem_cache *s, void *x) |
| { |
| kmemleak_free_recursive(x, s->flags); |
| |
| /* |
| * Trouble is that we may no longer disable interupts in the fast path |
| * So in order to make the debug calls that expect irqs to be |
| * disabled we need to disable interrupts temporarily. |
| */ |
| #if defined(CONFIG_KMEMCHECK) || defined(CONFIG_LOCKDEP) |
| { |
| unsigned long flags; |
| |
| local_irq_save(flags); |
| kmemcheck_slab_free(s, x, s->objsize); |
| debug_check_no_locks_freed(x, s->objsize); |
| local_irq_restore(flags); |
| } |
| #endif |
| if (!(s->flags & SLAB_DEBUG_OBJECTS)) |
| debug_check_no_obj_freed(x, s->objsize); |
| } |
| |
| /* |
| * Tracking of fully allocated slabs for debugging purposes. |
| * |
| * list_lock must be held. |
| */ |
| static void add_full(struct kmem_cache *s, |
| struct kmem_cache_node *n, struct page *page) |
| { |
| if (!(s->flags & SLAB_STORE_USER)) |
| return; |
| |
| list_add(&page->lru, &n->full); |
| } |
| |
| /* |
| * list_lock must be held. |
| */ |
| static void remove_full(struct kmem_cache *s, struct page *page) |
| { |
| if (!(s->flags & SLAB_STORE_USER)) |
| return; |
| |
| list_del(&page->lru); |
| } |
| |
| /* Tracking of the number of slabs for debugging purposes */ |
| static inline unsigned long slabs_node(struct kmem_cache *s, int node) |
| { |
| struct kmem_cache_node *n = get_node(s, node); |
| |
| return atomic_long_read(&n->nr_slabs); |
| } |
| |
| static inline unsigned long node_nr_slabs(struct kmem_cache_node *n) |
| { |
| return atomic_long_read(&n->nr_slabs); |
| } |
| |
| static inline void inc_slabs_node(struct kmem_cache *s, int node, int objects) |
| { |
| struct kmem_cache_node *n = get_node(s, node); |
| |
| /* |
| * May be called early in order to allocate a slab for the |
| * kmem_cache_node structure. Solve the chicken-egg |
| * dilemma by deferring the increment of the count during |
| * bootstrap (see early_kmem_cache_node_alloc). |
| */ |
| if (n) { |
| atomic_long_inc(&n->nr_slabs); |
| atomic_long_add(objects, &n->total_objects); |
| } |
| } |
| static inline void dec_slabs_node(struct kmem_cache *s, int node, int objects) |
| { |
| struct kmem_cache_node *n = get_node(s, node); |
| |
| atomic_long_dec(&n->nr_slabs); |
| atomic_long_sub(objects, &n->total_objects); |
| } |
| |
| /* Object debug checks for alloc/free paths */ |
| 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, SLUB_RED_INACTIVE); |
| init_tracking(s, object); |
| } |
| |
| static noinline int alloc_debug_processing(struct kmem_cache *s, struct page *page, |
| void *object, unsigned long addr) |
| { |
| if (!check_slab(s, page)) |
| goto bad; |
| |
| if (!check_valid_pointer(s, page, object)) { |
| object_err(s, page, object, "Freelist Pointer check fails"); |
| goto bad; |
| } |
| |
| if (!check_object(s, page, object, SLUB_RED_INACTIVE)) |
| 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, SLUB_RED_ACTIVE); |
| 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 = page->objects; |
| page->freelist = NULL; |
| } |
| return 0; |
| } |
| |
| static noinline int free_debug_processing(struct kmem_cache *s, |
| struct page *page, void *object, unsigned long addr) |
| { |
| unsigned long flags; |
| int rc = 0; |
| |
| local_irq_save(flags); |
| slab_lock(page); |
| |
| 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, SLUB_RED_ACTIVE)) |
| goto out; |
| |
| 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; |
| } |
| |
| if (s->flags & SLAB_STORE_USER) |
| set_track(s, object, TRACK_FREE, addr); |
| trace(s, page, object, 0); |
| init_object(s, object, SLUB_RED_INACTIVE); |
| rc = 1; |
| out: |
| slab_unlock(page); |
| local_irq_restore(flags); |
| return rc; |
| |
| fail: |
| slab_fix(s, "Object at 0x%p not freed", object); |
| goto out; |
| } |
| |
| 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; |
| |
| if (tolower(*str) == 'o') { |
| /* |
| * Avoid enabling debugging on caches if its minimum order |
| * would increase as a result. |
| */ |
| disable_higher_order_debug = 1; |
| goto out; |
| } |
| |
| 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; |
| case 'a': |
| slub_debug |= SLAB_FAILSLAB; |
| 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 unsigned long kmem_cache_flags(unsigned long objsize, |
| unsigned long flags, const char *name, |
| void (*ctor)(void *)) |
| { |
| /* |
| * Enable debugging if selected on the kernel commandline. |
| */ |
| if (slub_debug && (!slub_debug_slabs || |
| !strncmp(slub_debug_slabs, name, strlen(slub_debug_slabs)))) |
| flags |= slub_debug; |
| |
| return flags; |
| } |
| #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, unsigned long addr) { return 0; } |
| |
| static inline int free_debug_processing(struct kmem_cache *s, |
| struct page *page, void *object, unsigned long 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, u8 val) { return 1; } |
| static inline void add_full(struct kmem_cache *s, struct kmem_cache_node *n, |
| struct page *page) {} |
| static inline void remove_full(struct kmem_cache *s, struct page *page) {} |
| static inline unsigned long kmem_cache_flags(unsigned long objsize, |
| unsigned long flags, const char *name, |
| void (*ctor)(void *)) |
| { |
| return flags; |
| } |
| #define slub_debug 0 |
| |
| #define disable_higher_order_debug 0 |
| |
| static inline unsigned long slabs_node(struct kmem_cache *s, int node) |
| { return 0; } |
| static inline unsigned long node_nr_slabs(struct kmem_cache_node *n) |
| { return 0; } |
| static inline void inc_slabs_node(struct kmem_cache *s, int node, |
| int objects) {} |
| static inline void dec_slabs_node(struct kmem_cache *s, int node, |
| int objects) {} |
| |
| static inline int slab_pre_alloc_hook(struct kmem_cache *s, gfp_t flags) |
| { return 0; } |
| |
| static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags, |
| void *object) {} |
| |
| static inline void slab_free_hook(struct kmem_cache *s, void *x) {} |
| |
| #endif /* CONFIG_SLUB_DEBUG */ |
| |
| /* |
| * Slab allocation and freeing |
| */ |
| static inline struct page *alloc_slab_page(gfp_t flags, int node, |
| struct kmem_cache_order_objects oo) |
| { |
| int order = oo_order(oo); |
| |
| flags |= __GFP_NOTRACK; |
| |
| if (node == NUMA_NO_NODE) |
| return alloc_pages(flags, order); |
| else |
| return alloc_pages_exact_node(node, flags, order); |
| } |
| |
| static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node) |
| { |
| struct page *page; |
| struct kmem_cache_order_objects oo = s->oo; |
| gfp_t alloc_gfp; |
| |
| flags &= gfp_allowed_mask; |
| |
| if (flags & __GFP_WAIT) |
| local_irq_enable(); |
| |
| flags |= s->allocflags; |
| |
| /* |
| * Let the initial higher-order allocation fail under memory pressure |
| * so we fall-back to the minimum order allocation. |
| */ |
| alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY) & ~__GFP_NOFAIL; |
| |
| page = alloc_slab_page(alloc_gfp, node, oo); |
| if (unlikely(!page)) { |
| oo = s->min; |
| /* |
| * Allocation may have failed due to fragmentation. |
| * Try a lower order alloc if possible |
| */ |
| page = alloc_slab_page(flags, node, oo); |
| |
| if (page) |
| stat(s, ORDER_FALLBACK); |
| } |
| |
| if (flags & __GFP_WAIT) |
| local_irq_disable(); |
| |
| if (!page) |
| return NULL; |
| |
| if (kmemcheck_enabled |
| && !(s->flags & (SLAB_NOTRACK | DEBUG_DEFAULT_FLAGS))) { |
| int pages = 1 << oo_order(oo); |
| |
| kmemcheck_alloc_shadow(page, oo_order(oo), flags, node); |
| |
| /* |
| * Objects from caches that have a constructor don't get |
| * cleared when they're allocated, so we need to do it here. |
| */ |
| if (s->ctor) |
| kmemcheck_mark_uninitialized_pages(page, pages); |
| else |
| kmemcheck_mark_unallocated_pages(page, pages); |
| } |
| |
| page->objects = oo_objects(oo); |
| mod_zone_page_state(page_zone(page), |
| (s->flags & SLAB_RECLAIM_ACCOUNT) ? |
| NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE, |
| 1 << oo_order(oo)); |
| |
| 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); |
| } |
| |
| static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node) |
| { |
| struct page *page; |
| void *start; |
| void *last; |
| void *p; |
| |
| BUG_ON(flags & GFP_SLAB_BUG_MASK); |
| |
| page = allocate_slab(s, |
| flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node); |
| if (!page) |
| goto out; |
| |
| inc_slabs_node(s, page_to_nid(page), page->objects); |
| page->slab = s; |
| page->flags |= 1 << PG_slab; |
| |
| start = page_address(page); |
| |
| if (unlikely(s->flags & SLAB_POISON)) |
| memset(start, POISON_INUSE, PAGE_SIZE << compound_order(page)); |
| |
| last = start; |
| for_each_object(p, s, start, page->objects) { |
| 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->inuse = page->objects; |
| page->frozen = 1; |
| out: |
| return page; |
| } |
| |
| static void __free_slab(struct kmem_cache *s, struct page *page) |
| { |
| int order = compound_order(page); |
| int pages = 1 << order; |
| |
| if (kmem_cache_debug(s)) { |
| void *p; |
| |
| slab_pad_check(s, page); |
| for_each_object(p, s, page_address(page), |
| page->objects) |
| check_object(s, page, p, SLUB_RED_INACTIVE); |
| } |
| |
| kmemcheck_free_shadow(page, compound_order(page)); |
| |
| mod_zone_page_state(page_zone(page), |
| (s->flags & SLAB_RECLAIM_ACCOUNT) ? |
| NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE, |
| -pages); |
| |
| __ClearPageSlab(page); |
| reset_page_mapcount(page); |
| if (current->reclaim_state) |
| current->reclaim_state->reclaimed_slab += pages; |
| __free_pages(page, order); |
| } |
| |
| #define need_reserve_slab_rcu \ |
| (sizeof(((struct page *)NULL)->lru) < sizeof(struct rcu_head)) |
| |
| static void rcu_free_slab(struct rcu_head *h) |
| { |
| struct page *page; |
| |
| if (need_reserve_slab_rcu) |
| page = virt_to_head_page(h); |
| else |
| 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)) { |
| struct rcu_head *head; |
| |
| if (need_reserve_slab_rcu) { |
| int order = compound_order(page); |
| int offset = (PAGE_SIZE << order) - s->reserved; |
| |
| VM_BUG_ON(s->reserved != sizeof(*head)); |
| head = page_address(page) + offset; |
| } else { |
| /* |
| * RCU free overloads the RCU head over the LRU |
| */ |
| 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) |
| { |
| dec_slabs_node(s, page_to_nid(page), page->objects); |
| free_slab(s, page); |
| } |
| |
| /* |
| * Management of partially allocated slabs. |
| * |
| * list_lock must be held. |
| */ |
| static inline void add_partial(struct kmem_cache_node *n, |
| struct page *page, int tail) |
| { |
| n->nr_partial++; |
| if (tail == DEACTIVATE_TO_TAIL) |
| list_add_tail(&page->lru, &n->partial); |
| else |
| list_add(&page->lru, &n->partial); |
| } |
| |
| /* |
| * list_lock must be held. |
| */ |
| static inline void remove_partial(struct kmem_cache_node *n, |
| struct page *page) |
| { |
| list_del(&page->lru); |
| n->nr_partial--; |
| } |
| |
| /* |
| * Lock slab, remove from the partial list and put the object into the |
| * per cpu freelist. |
| * |
| * Returns a list of objects or NULL if it fails. |
| * |
| * Must hold list_lock. |
| */ |
| static inline void *acquire_slab(struct kmem_cache *s, |
| struct kmem_cache_node *n, struct page *page, |
| int mode) |
| { |
| void *freelist; |
| unsigned long counters; |
| struct page new; |
| |
| /* |
| * Zap the freelist and set the frozen bit. |
| * The old freelist is the list of objects for the |
| * per cpu allocation list. |
| */ |
| do { |
| freelist = page->freelist; |
| counters = page->counters; |
| new.counters = counters; |
| if (mode) { |
| new.inuse = page->objects; |
| new.freelist = NULL; |
| } else { |
| new.freelist = freelist; |
| } |
| |
| VM_BUG_ON(new.frozen); |
| new.frozen = 1; |
| |
| } while (!__cmpxchg_double_slab(s, page, |
| freelist, counters, |
| new.freelist, new.counters, |
| "lock and freeze")); |
| |
| remove_partial(n, page); |
| return freelist; |
| } |
| |
| static int put_cpu_partial(struct kmem_cache *s, struct page *page, int drain); |
| |
| /* |
| * Try to allocate a partial slab from a specific node. |
| */ |
| static void *get_partial_node(struct kmem_cache *s, |
| struct kmem_cache_node *n, struct kmem_cache_cpu *c) |
| { |
| struct page *page, *page2; |
| void *object = NULL; |
| |
| /* |
| * 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_safe(page, page2, &n->partial, lru) { |
| void *t = acquire_slab(s, n, page, object == NULL); |
| int available; |
| |
| if (!t) |
| break; |
| |
| if (!object) { |
| c->page = page; |
| c->node = page_to_nid(page); |
| stat(s, ALLOC_FROM_PARTIAL); |
| object = t; |
| available = page->objects - page->inuse; |
| } else { |
| available = put_cpu_partial(s, page, 0); |
| } |
| if (kmem_cache_debug(s) || available > s->cpu_partial / 2) |
| break; |
| |
| } |
| spin_unlock(&n->list_lock); |
| return object; |
| } |
| |
| /* |
| * Get a page from somewhere. Search in increasing NUMA distances. |
| */ |
| static struct page *get_any_partial(struct kmem_cache *s, gfp_t flags, |
| struct kmem_cache_cpu *c) |
| { |
| #ifdef CONFIG_NUMA |
| struct zonelist *zonelist; |
| struct zoneref *z; |
| struct zone *zone; |
| enum zone_type high_zoneidx = gfp_zone(flags); |
| void *object; |
| unsigned int cpuset_mems_cookie; |
| |
| /* |
| * 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/kernel/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->remote_node_defrag_ratio || |
| get_cycles() % 1024 > s->remote_node_defrag_ratio) |
| return NULL; |
| |
| do { |
| cpuset_mems_cookie = get_mems_allowed(); |
| zonelist = node_zonelist(slab_node(current->mempolicy), flags); |
| for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) { |
| struct kmem_cache_node *n; |
| |
| n = get_node(s, zone_to_nid(zone)); |
| |
| if (n && cpuset_zone_allowed_hardwall(zone, flags) && |
| n->nr_partial > s->min_partial) { |
| object = get_partial_node(s, n, c); |
| if (object) { |
| /* |
| * Return the object even if |
| * put_mems_allowed indicated that |
| * the cpuset mems_allowed was |
| * updated in parallel. It's a |
| * harmless race between the alloc |
| * and the cpuset update. |
| */ |
| put_mems_allowed(cpuset_mems_cookie); |
| return object; |
| } |
| } |
| } |
| } while (!put_mems_allowed(cpuset_mems_cookie)); |
| #endif |
| return NULL; |
| } |
| |
| /* |
| * Get a partial page, lock it and return it. |
| */ |
| static void *get_partial(struct kmem_cache *s, gfp_t flags, int node, |
| struct kmem_cache_cpu *c) |
| { |
| void *object; |
| int searchnode = (node == NUMA_NO_NODE) ? numa_node_id() : node; |
| |
| object = get_partial_node(s, get_node(s, searchnode), c); |
| if (object || node != NUMA_NO_NODE) |
| return object; |
| |
| return get_any_partial(s, flags, c); |
| } |
| |
| #ifdef CONFIG_PREEMPT |
| /* |
| * Calculate the next globally unique transaction for disambiguiation |
| * during cmpxchg. The transactions start with the cpu number and are then |
| * incremented by CONFIG_NR_CPUS. |
| */ |
| #define TID_STEP roundup_pow_of_two(CONFIG_NR_CPUS) |
| #else |
| /* |
| * No preemption supported therefore also no need to check for |
| * different cpus. |
| */ |
| #define TID_STEP 1 |
| #endif |
| |
| static inline unsigned long next_tid(unsigned long tid) |
| { |
| return tid + TID_STEP; |
| } |
| |
| static inline unsigned int tid_to_cpu(unsigned long tid) |
| { |
| return tid % TID_STEP; |
| } |
| |
| static inline unsigned long tid_to_event(unsigned long tid) |
| { |
| return tid / TID_STEP; |
| } |
| |
| static inline unsigned int init_tid(int cpu) |
| { |
| return cpu; |
| } |
| |
| static inline void note_cmpxchg_failure(const char *n, |
| const struct kmem_cache *s, unsigned long tid) |
| { |
| #ifdef SLUB_DEBUG_CMPXCHG |
| unsigned long actual_tid = __this_cpu_read(s->cpu_slab->tid); |
| |
| printk(KERN_INFO "%s %s: cmpxchg redo ", n, s->name); |
| |
| #ifdef CONFIG_PREEMPT |
| if (tid_to_cpu(tid) != tid_to_cpu(actual_tid)) |
| printk("due to cpu change %d -> %d\n", |
| tid_to_cpu(tid), tid_to_cpu(actual_tid)); |
| else |
| #endif |
| if (tid_to_event(tid) != tid_to_event(actual_tid)) |
| printk("due to cpu running other code. Event %ld->%ld\n", |
| tid_to_event(tid), tid_to_event(actual_tid)); |
| else |
| printk("for unknown reason: actual=%lx was=%lx target=%lx\n", |
| actual_tid, tid, next_tid(tid)); |
| #endif |
| stat(s, CMPXCHG_DOUBLE_CPU_FAIL); |
| } |
| |
| void init_kmem_cache_cpus(struct kmem_cache *s) |
| { |
| int cpu; |
| |
| for_each_possible_cpu(cpu) |
| per_cpu_ptr(s->cpu_slab, cpu)->tid = init_tid(cpu); |
| } |
| |
| /* |
| * Remove the cpu slab |
| */ |
| static void deactivate_slab(struct kmem_cache *s, struct kmem_cache_cpu *c) |
| { |
| enum slab_modes { M_NONE, M_PARTIAL, M_FULL, M_FREE }; |
| struct page *page = c->page; |
| struct kmem_cache_node *n = get_node(s, page_to_nid(page)); |
| int lock = 0; |
| enum slab_modes l = M_NONE, m = M_NONE; |
| void *freelist; |
| void *nextfree; |
| int tail = DEACTIVATE_TO_HEAD; |
| struct page new; |
| struct page old; |
| |
| if (page->freelist) { |
| stat(s, DEACTIVATE_REMOTE_FREES); |
| tail = DEACTIVATE_TO_TAIL; |
| } |
| |
| c->tid = next_tid(c->tid); |
| c->page = NULL; |
| freelist = c->freelist; |
| c->freelist = NULL; |
| |
| /* |
| * Stage one: Free all available per cpu objects back |
| * to the page freelist while it is still frozen. Leave the |
| * last one. |
| * |
| * There is no need to take the list->lock because the page |
| * is still frozen. |
| */ |
| while (freelist && (nextfree = get_freepointer(s, freelist))) { |
| void *prior; |
| unsigned long counters; |
| |
| do { |
| prior = page->freelist; |
| counters = page->counters; |
| set_freepointer(s, freelist, prior); |
| new.counters = counters; |
| new.inuse--; |
| VM_BUG_ON(!new.frozen); |
| |
| } while (!__cmpxchg_double_slab(s, page, |
| prior, counters, |
| freelist, new.counters, |
| "drain percpu freelist")); |
| |
| freelist = nextfree; |
| } |
| |
| /* |
| * Stage two: Ensure that the page is unfrozen while the |
| * list presence reflects the actual number of objects |
| * during unfreeze. |
| * |
| * We setup the list membership and then perform a cmpxchg |
| * with the count. If there is a mismatch then the page |
| * is not unfrozen but the page is on the wrong list. |
| * |
| * Then we restart the process which may have to remove |
| * the page from the list that we just put it on again |
| * because the number of objects in the slab may have |
| * changed. |
| */ |
| redo: |
| |
| old.freelist = page->freelist; |
| old.counters = page->counters; |
| VM_BUG_ON(!old.frozen); |
| |
| /* Determine target state of the slab */ |
| new.counters = old.counters; |
| if (freelist) { |
| new.inuse--; |
| set_freepointer(s, freelist, old.freelist); |
| new.freelist = freelist; |
| } else |
| new.freelist = old.freelist; |
| |
| new.frozen = 0; |
| |
| if (!new.inuse && n->nr_partial > s->min_partial) |
| m = M_FREE; |
| else if (new.freelist) { |
| m = M_PARTIAL; |
| if (!lock) { |
| lock = 1; |
| /* |
| * Taking the spinlock removes the possiblity |
| * that acquire_slab() will see a slab page that |
| * is frozen |
| */ |
| spin_lock(&n->list_lock); |
| } |
| } else { |
| m = M_FULL; |
| if (kmem_cache_debug(s) && !lock) { |
| lock = 1; |
| /* |
| * This also ensures that the scanning of full |
| * slabs from diagnostic functions will not see |
| * any frozen slabs. |
| */ |
| spin_lock(&n->list_lock); |
| } |
| } |
| |
| if (l != m) { |
| |
| if (l == M_PARTIAL) |
| |
| remove_partial(n, page); |
| |
| else if (l == M_FULL) |
| |
| remove_full(s, page); |
| |
| if (m == M_PARTIAL) { |
| |
| add_partial(n, page, tail); |
| stat(s, tail); |
| |
| } else if (m == M_FULL) { |
| |
| stat(s, DEACTIVATE_FULL); |
| add_full(s, n, page); |
| |
| } |
| } |
| |
| l = m; |
| if (!__cmpxchg_double_slab(s, page, |
| old.freelist, old.counters, |
| new.freelist, new.counters, |
| "unfreezing slab")) |
| goto redo; |
| |
| if (lock) |
| spin_unlock(&n->list_lock); |
| |
| if (m == M_FREE) { |
| stat(s, DEACTIVATE_EMPTY); |
| discard_slab(s, page); |
| stat(s, FREE_SLAB); |
| } |
| } |
| |
| /* Unfreeze all the cpu partial slabs */ |
| static void unfreeze_partials(struct kmem_cache *s) |
| { |
| struct kmem_cache_node *n = NULL; |
| struct kmem_cache_cpu *c = this_cpu_ptr(s->cpu_slab); |
| struct page *page, *discard_page = NULL; |
| |
| while ((page = c->partial)) { |
| enum slab_modes { M_PARTIAL, M_FREE }; |
| enum slab_modes l, m; |
| struct page new; |
| struct page old; |
| |
| c->partial = page->next; |
| l = M_FREE; |
| |
| do { |
| |
| old.freelist = page->freelist; |
| old.counters = page->counters; |
| VM_BUG_ON(!old.frozen); |
| |
| new.counters = old.counters; |
| new.freelist = old.freelist; |
| |
| new.frozen = 0; |
| |
| if (!new.inuse && (!n || n->nr_partial > s->min_partial)) |
| m = M_FREE; |
| else { |
| struct kmem_cache_node *n2 = get_node(s, |
| page_to_nid(page)); |
| |
| m = M_PARTIAL; |
| if (n != n2) { |
| if (n) |
| spin_unlock(&n->list_lock); |
| |
| n = n2; |
| spin_lock(&n->list_lock); |
| } |
| } |
| |
| if (l != m) { |
| if (l == M_PARTIAL) |
| remove_partial(n, page); |
| else |
| add_partial(n, page, |
| DEACTIVATE_TO_TAIL); |
| |
| l = m; |
| } |
| |
| } while (!cmpxchg_double_slab(s, page, |
| old.freelist, old.counters, |
| new.freelist, new.counters, |
| "unfreezing slab")); |
| |
| if (m == M_FREE) { |
| page->next = discard_page; |
| discard_page = page; |
| } |
| } |
| |
| if (n) |
| spin_unlock(&n->list_lock); |
| |
| while (discard_page) { |
| page = discard_page; |
| discard_page = discard_page->next; |
| |
| stat(s, DEACTIVATE_EMPTY); |
| discard_slab(s, page); |
| stat(s, FREE_SLAB); |
| } |
| } |
| |
| /* |
| * Put a page that was just frozen (in __slab_free) into a partial page |
| * slot if available. This is done without interrupts disabled and without |
| * preemption disabled. The cmpxchg is racy and may put the partial page |
| * onto a random cpus partial slot. |
| * |
| * If we did not find a slot then simply move all the partials to the |
| * per node partial list. |
| */ |
| int put_cpu_partial(struct kmem_cache *s, struct page *page, int drain) |
| { |
| struct page *oldpage; |
| int pages; |
| int pobjects; |
| |
| do { |
| pages = 0; |
| pobjects = 0; |
| oldpage = this_cpu_read(s->cpu_slab->partial); |
| |
| if (oldpage) { |
| pobjects = oldpage->pobjects; |
| pages = oldpage->pages; |
| if (drain && pobjects > s->cpu_partial) { |
| unsigned long flags; |
| /* |
| * partial array is full. Move the existing |
| * set to the per node partial list. |
| */ |
| local_irq_save(flags); |
| unfreeze_partials(s); |
| local_irq_restore(flags); |
| pobjects = 0; |
| pages = 0; |
| } |
| } |
| |
| pages++; |
| pobjects += page->objects - page->inuse; |
| |
| page->pages = pages; |
| page->pobjects = pobjects; |
| page->next = oldpage; |
| |
| } while (irqsafe_cpu_cmpxchg(s->cpu_slab->partial, oldpage, page) != oldpage); |
| stat(s, CPU_PARTIAL_FREE); |
| return pobjects; |
| } |
| |
| static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c) |
| { |
| stat(s, CPUSLAB_FLUSH); |
| deactivate_slab(s, c); |
| } |
| |
| /* |
| * Flush cpu slab. |
| * |
| * Called from IPI handler with interrupts disabled. |
| */ |
| static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu) |
| { |
| struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu); |
| |
| if (likely(c)) { |
| if (c->page) |
| flush_slab(s, c); |
| |
| unfreeze_partials(s); |
| } |
| } |
| |
| static void flush_cpu_slab(void *d) |
| { |
| struct kmem_cache *s = d; |
| |
| __flush_cpu_slab(s, smp_processor_id()); |
| } |
| |
| static void flush_all(struct kmem_cache *s) |
| { |
| on_each_cpu(flush_cpu_slab, s, 1); |
| } |
| |
| /* |
| * Check if the objects in a per cpu structure fit numa |
| * locality expectations. |
| */ |
| static inline int node_match(struct kmem_cache_cpu *c, int node) |
| { |
| #ifdef CONFIG_NUMA |
| if (node != NUMA_NO_NODE && c->node != node) |
| return 0; |
| #endif |
| return 1; |
| } |
| |
| static int count_free(struct page *page) |
| { |
| return page->objects - page->inuse; |
| } |
| |
| static unsigned long count_partial(struct kmem_cache_node *n, |
| int (*get_count)(struct page *)) |
| { |
| 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 += get_count(page); |
| spin_unlock_irqrestore(&n->list_lock, flags); |
| return x; |
| } |
| |
| static inline unsigned long node_nr_objs(struct kmem_cache_node *n) |
| { |
| #ifdef CONFIG_SLUB_DEBUG |
| return atomic_long_read(&n->total_objects); |
| #else |
| return 0; |
| #endif |
| } |
| |
| static noinline void |
| slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid) |
| { |
| int node; |
| |
| printk(KERN_WARNING |
| "SLUB: Unable to allocate memory on node %d (gfp=0x%x)\n", |
| nid, gfpflags); |
| printk(KERN_WARNING " cache: %s, object size: %d, buffer size: %d, " |
| "default order: %d, min order: %d\n", s->name, s->objsize, |
| s->size, oo_order(s->oo), oo_order(s->min)); |
| |
| if (oo_order(s->min) > get_order(s->objsize)) |
| printk(KERN_WARNING " %s debugging increased min order, use " |
| "slub_debug=O to disable.\n", s->name); |
| |
| for_each_online_node(node) { |
| struct kmem_cache_node *n = get_node(s, node); |
| unsigned long nr_slabs; |
| unsigned long nr_objs; |
| unsigned long nr_free; |
| |
| if (!n) |
| continue; |
| |
| nr_free = count_partial(n, count_free); |
| nr_slabs = node_nr_slabs(n); |
| nr_objs = node_nr_objs(n); |
| |
| printk(KERN_WARNING |
| " node %d: slabs: %ld, objs: %ld, free: %ld\n", |
| node, nr_slabs, nr_objs, nr_free); |
| } |
| } |
| |
| static inline void *new_slab_objects(struct kmem_cache *s, gfp_t flags, |
| int node, struct kmem_cache_cpu **pc) |
| { |
| void *object; |
| struct kmem_cache_cpu *c; |
| struct page *page = new_slab(s, flags, node); |
| |
| if (page) { |
| c = __this_cpu_ptr(s->cpu_slab); |
| if (c->page) |
| flush_slab(s, c); |
| |
| /* |
| * No other reference to the page yet so we can |
| * muck around with it freely without cmpxchg |
| */ |
| object = page->freelist; |
| page->freelist = NULL; |
| |
| stat(s, ALLOC_SLAB); |
| c->node = page_to_nid(page); |
| c->page = page; |
| *pc = c; |
| } else |
| object = NULL; |
| |
| return object; |
| } |
| |
| /* |
| * Slow path. The lockless freelist is empty or we need to perform |
| * debugging duties. |
| * |
| * 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 the slowest path since it involves |
| * a call to the page allocator and the setup of a new slab. |
| */ |
| static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node, |
| unsigned long addr, struct kmem_cache_cpu *c) |
| { |
| void **object; |
| unsigned long flags; |
| struct page new; |
| unsigned long counters; |
| |
| local_irq_save(flags); |
| #ifdef CONFIG_PREEMPT |
| /* |
| * We may have been preempted and rescheduled on a different |
| * cpu before disabling interrupts. Need to reload cpu area |
| * pointer. |
| */ |
| c = this_cpu_ptr(s->cpu_slab); |
| #endif |
| |
| if (!c->page) |
| goto new_slab; |
| redo: |
| if (unlikely(!node_match(c, node))) { |
| stat(s, ALLOC_NODE_MISMATCH); |
| deactivate_slab(s, c); |
| goto new_slab; |
| } |
| |
| /* must check again c->freelist in case of cpu migration or IRQ */ |
| object = c->freelist; |
| if (object) |
| goto load_freelist; |
| |
| stat(s, ALLOC_SLOWPATH); |
| |
| do { |
| object = c->page->freelist; |
| counters = c->page->counters; |
| new.counters = counters; |
| VM_BUG_ON(!new.frozen); |
| |
| /* |
| * If there is no object left then we use this loop to |
| * deactivate the slab which is simple since no objects |
| * are left in the slab and therefore we do not need to |
| * put the page back onto the partial list. |
| * |
| * If there are objects left then we retrieve them |
| * and use them to refill the per cpu queue. |
| */ |
| |
| new.inuse = c->page->objects; |
| new.frozen = object != NULL; |
| |
| } while (!__cmpxchg_double_slab(s, c->page, |
| object, counters, |
| NULL, new.counters, |
| "__slab_alloc")); |
| |
| if (!object) { |
| c->page = NULL; |
| stat(s, DEACTIVATE_BYPASS); |
| goto new_slab; |
| } |
| |
| stat(s, ALLOC_REFILL); |
| |
| load_freelist: |
| c->freelist = get_freepointer(s, object); |
| c->tid = next_tid(c->tid); |
| local_irq_restore(flags); |
| return object; |
| |
| new_slab: |
| |
| if (c->partial) { |
| c->page = c->partial; |
| c->partial = c->page->next; |
| c->node = page_to_nid(c->page); |
| stat(s, CPU_PARTIAL_ALLOC); |
| c->freelist = NULL; |
| goto redo; |
| } |
| |
| /* Then do expensive stuff like retrieving pages from the partial lists */ |
| object = get_partial(s, gfpflags, node, c); |
| |
| if (unlikely(!object)) { |
| |
| object = new_slab_objects(s, gfpflags, node, &c); |
| |
| if (unlikely(!object)) { |
| if (!(gfpflags & __GFP_NOWARN) && printk_ratelimit()) |
| slab_out_of_memory(s, gfpflags, node); |
| |
| local_irq_restore(flags); |
| return NULL; |
| } |
| } |
| |
| if (likely(!kmem_cache_debug(s))) |
| goto load_freelist; |
| |
| /* Only entered in the debug case */ |
| if (!alloc_debug_processing(s, c->page, object, addr)) |
| goto new_slab; /* Slab failed checks. Next slab needed */ |
| |
| c->freelist = get_freepointer(s, object); |
| deactivate_slab(s, c); |
| c->node = NUMA_NO_NODE; |
| local_irq_restore(flags); |
| 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 __always_inline void *slab_alloc(struct kmem_cache *s, |
| gfp_t gfpflags, int node, unsigned long addr) |
| { |
| void **object; |
| struct kmem_cache_cpu *c; |
| unsigned long tid; |
| |
| if (slab_pre_alloc_hook(s, gfpflags)) |
| return NULL; |
| |
| redo: |
| |
| /* |
| * Must read kmem_cache cpu data via this cpu ptr. Preemption is |
| * enabled. We may switch back and forth between cpus while |
| * reading from one cpu area. That does not matter as long |
| * as we end up on the original cpu again when doing the cmpxchg. |
| */ |
| c = __this_cpu_ptr(s->cpu_slab); |
| |
| /* |
| * The transaction ids are globally unique per cpu and per operation on |
| * a per cpu queue. Thus they can be guarantee that the cmpxchg_double |
| * occurs on the right processor and that there was no operation on the |
| * linked list in between. |
| */ |
| tid = c->tid; |
| barrier(); |
| |
| object = c->freelist; |
| if (unlikely(!object || !node_match(c, node))) |
| |
| object = __slab_alloc(s, gfpflags, node, addr, c); |
| |
| else { |
| /* |
| * The cmpxchg will only match if there was no additional |
| * operation and if we are on the right processor. |
| * |
| * The cmpxchg does the following atomically (without lock semantics!) |
| * 1. Relocate first pointer to the current per cpu area. |
| * 2. Verify that tid and freelist have not been changed |
| * 3. If they were not changed replace tid and freelist |
| * |
| * Since this is without lock semantics the protection is only against |
| * code executing on this cpu *not* from access by other cpus. |
| */ |
| if (unlikely(!irqsafe_cpu_cmpxchg_double( |
| s->cpu_slab->freelist, s->cpu_slab->tid, |
| object, tid, |
| get_freepointer_safe(s, object), next_tid(tid)))) { |
| |
| note_cmpxchg_failure("slab_alloc", s, tid); |
| goto redo; |
| } |
| stat(s, ALLOC_FASTPATH); |
| } |
| |
| if (unlikely(gfpflags & __GFP_ZERO) && object) |
| memset(object, 0, s->objsize); |
| |
| slab_post_alloc_hook(s, gfpflags, object); |
| |
| return object; |
| } |
| |
| void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags) |
| { |
| void *ret = slab_alloc(s, gfpflags, NUMA_NO_NODE, _RET_IP_); |
| |
| trace_kmem_cache_alloc(_RET_IP_, ret, s->objsize, s->size, gfpflags); |
| |
| return ret; |
| } |
| EXPORT_SYMBOL(kmem_cache_alloc); |
| |
| #ifdef CONFIG_TRACING |
| void *kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size) |
| { |
| void *ret = slab_alloc(s, gfpflags, NUMA_NO_NODE, _RET_IP_); |
| trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags); |
| return ret; |
| } |
| EXPORT_SYMBOL(kmem_cache_alloc_trace); |
| |
| void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order) |
| { |
| void *ret = kmalloc_order(size, flags, order); |
| trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << order, flags); |
| return ret; |
| } |
| EXPORT_SYMBOL(kmalloc_order_trace); |
| #endif |
| |
| #ifdef CONFIG_NUMA |
| void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node) |
| { |
| void *ret = slab_alloc(s, gfpflags, node, _RET_IP_); |
| |
| trace_kmem_cache_alloc_node(_RET_IP_, ret, |
| s->objsize, s->size, gfpflags, node); |
| |
| return ret; |
| } |
| EXPORT_SYMBOL(kmem_cache_alloc_node); |
| |
| #ifdef CONFIG_TRACING |
| void *kmem_cache_alloc_node_trace(struct kmem_cache *s, |
| gfp_t gfpflags, |
| int node, size_t size) |
| { |
| void *ret = slab_alloc(s, gfpflags, node, _RET_IP_); |
| |
| trace_kmalloc_node(_RET_IP_, ret, |
| size, s->size, gfpflags, node); |
| return ret; |
| } |
| EXPORT_SYMBOL(kmem_cache_alloc_node_trace); |
| #endif |
| #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, unsigned long addr) |
| { |
| void *prior; |
| void **object = (void *)x; |
| int was_frozen; |
| int inuse; |
| struct page new; |
| unsigned long counters; |
| struct kmem_cache_node *n = NULL; |
| unsigned long uninitialized_var(flags); |
| |
| stat(s, FREE_SLOWPATH); |
| |
| if (kmem_cache_debug(s) && !free_debug_processing(s, page, x, addr)) |
| return; |
| |
| do { |
| prior = page->freelist; |
| counters = page->counters; |
| set_freepointer(s, object, prior); |
| new.counters = counters; |
| was_frozen = new.frozen; |
| new.inuse--; |
| if ((!new.inuse || !prior) && !was_frozen && !n) { |
| |
| if (!kmem_cache_debug(s) && !prior) |
| |
| /* |
| * Slab was on no list before and will be partially empty |
| * We can defer the list move and instead freeze it. |
| */ |
| new.frozen = 1; |
| |
| else { /* Needs to be taken off a list */ |
| |
| n = get_node(s, page_to_nid(page)); |
| /* |
| * Speculatively acquire the list_lock. |
| * If the cmpxchg does not succeed then we may |
| * drop the list_lock without any processing. |
| * |
| * Otherwise the list_lock will synchronize with |
| * other processors updating the list of slabs. |
| */ |
| spin_lock_irqsave(&n->list_lock, flags); |
| |
| } |
| } |
| inuse = new.inuse; |
| |
| } while (!cmpxchg_double_slab(s, page, |
| prior, counters, |
| object, new.counters, |
| "__slab_free")); |
| |
| if (likely(!n)) { |
| |
| /* |
| * If we just froze the page then put it onto the |
| * per cpu partial list. |
| */ |
| if (new.frozen && !was_frozen) |
| put_cpu_partial(s, page, 1); |
| |
| /* |
| * The list lock was not taken therefore no list |
| * activity can be necessary. |
| */ |
| if (was_frozen) |
| stat(s, FREE_FROZEN); |
| return; |
| } |
| |
| /* |
| * was_frozen may have been set after we acquired the list_lock in |
| * an earlier loop. So we need to check it here again. |
| */ |
| if (was_frozen) |
| stat(s, FREE_FROZEN); |
| else { |
| if (unlikely(!inuse && n->nr_partial > s->min_partial)) |
| goto slab_empty; |
| |
| /* |
| * Objects left in the slab. If it was not on the partial list before |
| * then add it. |
| */ |
| if (unlikely(!prior)) { |
| remove_full(s, page); |
| add_partial(n, page, DEACTIVATE_TO_TAIL); |
| stat(s, FREE_ADD_PARTIAL); |
| } |
| } |
| spin_unlock_irqrestore(&n->list_lock, flags); |
| return; |
| |
| slab_empty: |
| if (prior) { |
| /* |
| * Slab on the partial list. |
| */ |
| remove_partial(n, page); |
| stat(s, FREE_REMOVE_PARTIAL); |
| } else |
| /* Slab must be on the full list */ |
| remove_full(s, page); |
| |
| spin_unlock_irqrestore(&n->list_lock, flags); |
| stat(s, FREE_SLAB); |
| discard_slab(s, page); |
| } |
| |
| /* |
| * 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 __always_inline void slab_free(struct kmem_cache *s, |
| struct page *page, void *x, unsigned long addr) |
| { |
| void **object = (void *)x; |
| struct kmem_cache_cpu *c; |
| unsigned long tid; |
| |
| slab_free_hook(s, x); |
| |
| redo: |
| /* |
| * Determine the currently cpus per cpu slab. |
| * The cpu may change afterward. However that does not matter since |
| * data is retrieved via this pointer. If we are on the same cpu |
| * during the cmpxchg then the free will succedd. |
| */ |
| c = __this_cpu_ptr(s->cpu_slab); |
| |
| tid = c->tid; |
| barrier(); |
| |
| if (likely(page == c->page)) { |
| set_freepointer(s, object, c->freelist); |
| |
| if (unlikely(!irqsafe_cpu_cmpxchg_double( |
| s->cpu_slab->freelist, s->cpu_slab->tid, |
| c->freelist, tid, |
| object, next_tid(tid)))) { |
| |
| note_cmpxchg_failure("slab_free", s, tid); |
| goto redo; |
| } |
| stat(s, FREE_FASTPATH); |
| } else |
| __slab_free(s, page, x, addr); |
| |
| } |
| |
| void kmem_cache_free(struct kmem_cache *s, void *x) |
| { |
| struct page *page; |
| |
| page = virt_to_head_page(x); |
| |
| slab_free(s, page, x, _RET_IP_); |
| |
| trace_kmem_cache_free(_RET_IP_, x); |
| } |
| EXPORT_SYMBOL(kmem_cache_free); |
| |
| /* |
| * 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 = PAGE_ALLOC_COSTLY_ORDER; |
| static int slub_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 1/16th 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 reserved) |
| { |
| int order; |
| int rem; |
| int min_order = slub_min_order; |
| |
| if (order_objects(min_order, size, reserved) > MAX_OBJS_PER_PAGE) |
| return get_order(size * MAX_OBJS_PER_PAGE) - 1; |
| |
| 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 + reserved) |
| continue; |
| |
| rem = (slab_size - reserved) % size; |
| |
| if (rem <= slab_size / fract_leftover) |
| break; |
| |
| } |
| |
| return order; |
| } |
| |
| static inline int calculate_order(int size, int reserved) |
| { |
| int order; |
| int min_objects; |
| int fraction; |
| int max_objects; |
| |
| /* |
| * 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; |
| if (!min_objects) |
| min_objects = 4 * (fls(nr_cpu_ids) + 1); |
| max_objects = order_objects(slub_max_order, size, reserved); |
| min_objects = min(min_objects, max_objects); |
| |
| while (min_objects > 1) { |
| fraction = 16; |
| while (fraction >= 4) { |
| order = slab_order(size, min_objects, |
| slub_max_order, fraction, reserved); |
| if (order <= slub_max_order) |
| return order; |
| fraction /= 2; |
| } |
| min_objects--; |
| } |
| |
| /* |
| * 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, reserved); |
| 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, reserved); |
| 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) { |
| unsigned long ralign = cache_line_size(); |
| while (size <= ralign / 2) |
| ralign /= 2; |
| align = max(align, ralign); |
| } |
| |
| if (align < ARCH_SLAB_MINALIGN) |
| align = ARCH_SLAB_MINALIGN; |
| |
| return ALIGN(align, sizeof(void *)); |
| } |
| |
| static void |
| init_kmem_cache_node(struct kmem_cache_node *n, struct kmem_cache *s) |
| { |
| n->nr_partial = 0; |
| spin_lock_init(&n->list_lock); |
| INIT_LIST_HEAD(&n->partial); |
| #ifdef CONFIG_SLUB_DEBUG |
| atomic_long_set(&n->nr_slabs, 0); |
| atomic_long_set(&n->total_objects, 0); |
| INIT_LIST_HEAD(&n->full); |
| #endif |
| } |
| |
| static inline int alloc_kmem_cache_cpus(struct kmem_cache *s) |
| { |
| BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE < |
| SLUB_PAGE_SHIFT * sizeof(struct kmem_cache_cpu)); |
| |
| /* |
| * Must align to double word boundary for the double cmpxchg |
| * instructions to work; see __pcpu_double_call_return_bool(). |
| */ |
| s->cpu_slab = __alloc_percpu(sizeof(struct kmem_cache_cpu), |
| 2 * sizeof(void *)); |
| |
| if (!s->cpu_slab) |
| return 0; |
| |
| init_kmem_cache_cpus(s); |
| |
| return 1; |
| } |
| |
| static struct kmem_cache *kmem_cache_node; |
| |
| /* |
| * 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. This is used for bootstrapping |
| * memory on a fresh node that has no slab structures yet. |
| */ |
| static void early_kmem_cache_node_alloc(int node) |
| { |
| struct page *page; |
| struct kmem_cache_node *n; |
| |
| BUG_ON(kmem_cache_node->size < sizeof(struct kmem_cache_node)); |
| |
| page = new_slab(kmem_cache_node, GFP_NOWAIT, node); |
| |
| BUG_ON(!page); |
| if (page_to_nid(page) != node) { |
| printk(KERN_ERR "SLUB: Unable to allocate memory from " |
| "node %d\n", node); |
| printk(KERN_ERR "SLUB: Allocating a useless per node structure " |
| "in order to be able to continue\n"); |
| } |
| |
| n = page->freelist; |
| BUG_ON(!n); |
| page->freelist = get_freepointer(kmem_cache_node, n); |
| page->inuse = 1; |
| page->frozen = 0; |
| kmem_cache_node->node[node] = n; |
| #ifdef CONFIG_SLUB_DEBUG |
| init_object(kmem_cache_node, n, SLUB_RED_ACTIVE); |
| init_tracking(kmem_cache_node, n); |
| #endif |
| init_kmem_cache_node(n, kmem_cache_node); |
| inc_slabs_node(kmem_cache_node, node, page->objects); |
| |
| add_partial(n, page, DEACTIVATE_TO_HEAD); |
| } |
| |
| static void free_kmem_cache_nodes(struct kmem_cache *s) |
| { |
| int node; |
| |
| for_each_node_state(node, N_NORMAL_MEMORY) { |
| struct kmem_cache_node *n = s->node[node]; |
| |
| if (n) |
| kmem_cache_free(kmem_cache_node, n); |
| |
| s->node[node] = NULL; |
| } |
| } |
| |
| static int init_kmem_cache_nodes(struct kmem_cache *s) |
| { |
| int node; |
| |
| for_each_node_state(node, N_NORMAL_MEMORY) { |
| struct kmem_cache_node *n; |
| |
| if (slab_state == DOWN) { |
| early_kmem_cache_node_alloc(node); |
| continue; |
| } |
| n = kmem_cache_alloc_node(kmem_cache_node, |
| GFP_KERNEL, node); |
| |
| if (!n) { |
| free_kmem_cache_nodes(s); |
| return 0; |
| } |
| |
| s->node[node] = n; |
| init_kmem_cache_node(n, s); |
| } |
| return 1; |
| } |
| |
| static void set_min_partial(struct kmem_cache *s, unsigned long min) |
| { |
| if (min < MIN_PARTIAL) |
| min = MIN_PARTIAL; |
| else if (min > MAX_PARTIAL) |
| min = MAX_PARTIAL; |
| s->min_partial = min; |
| } |
| |
| /* |
| * calculate_sizes() determines the order and the distribution of data within |
| * a slab object. |
| */ |
| static int calculate_sizes(struct kmem_cache *s, int forced_order) |
| { |
| unsigned long flags = s->flags; |
| unsigned long size = s->objsize; |
| unsigned long align = s->align; |
| int order; |
| |
| /* |
| * 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 |
| /* |
| * 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; |
| |
| |
| /* |
| * 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 a 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); |
| s->align = align; |
| |
| /* |
| * 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; |
| if (forced_order >= 0) |
| order = forced_order; |
| else |
| order = calculate_order(size, s->reserved); |
| |
| if (order < 0) |
| return 0; |
| |
| s->allocflags = 0; |
| if (order) |
| s->allocflags |= __GFP_COMP; |
| |
| if (s->flags & SLAB_CACHE_DMA) |
| s->allocflags |= SLUB_DMA; |
| |
| if (s->flags & SLAB_RECLAIM_ACCOUNT) |
| s->allocflags |= __GFP_RECLAIMABLE; |
| |
| /* |
| * Determine the number of objects per slab |
| */ |
| s->oo = oo_make(order, size, s->reserved); |
| s->min = oo_make(get_order(size), size, s->reserved); |
| if (oo_objects(s->oo) > oo_objects(s->max)) |
| s->max = s->oo; |
| |
| return !!oo_objects(s->oo); |
| |
| } |
| |
| static int kmem_cache_open(struct kmem_cache *s, |
| const char *name, size_t size, |
| size_t align, unsigned long flags, |
| void (*ctor)(void *)) |
| { |
| memset(s, 0, kmem_size); |
| s->name = name; |
| s->ctor = ctor; |
| s->objsize = size; |
| s->align = align; |
| s->flags = kmem_cache_flags(size, flags, name, ctor); |
| s->reserved = 0; |
| |
| if (need_reserve_slab_rcu && (s->flags & SLAB_DESTROY_BY_RCU)) |
| s->reserved = sizeof(struct rcu_head); |
| |
| if (!calculate_sizes(s, -1)) |
| goto error; |
| if (disable_higher_order_debug) { |
| /* |
| * Disable debugging flags that store metadata if the min slab |
| * order increased. |
| */ |
| if (get_order(s->size) > get_order(s->objsize)) { |
| s->flags &= ~DEBUG_METADATA_FLAGS; |
| s->offset = 0; |
| if (!calculate_sizes(s, -1)) |
| goto error; |
| } |
| } |
| |
| #ifdef CONFIG_CMPXCHG_DOUBLE |
| if (system_has_cmpxchg_double() && (s->flags & SLAB_DEBUG_FLAGS) == 0) |
| /* Enable fast mode */ |
| s->flags |= __CMPXCHG_DOUBLE; |
| #endif |
| |
| /* |
| * The larger the object size is, the more pages we want on the partial |
| * list to avoid pounding the page allocator excessively. |
| */ |
| set_min_partial(s, ilog2(s->size) / 2); |
| |
| /* |
| * cpu_partial determined the maximum number of objects kept in the |
| * per cpu partial lists of a processor. |
| * |
| * Per cpu partial lists mainly contain slabs that just have one |
| * object freed. If they are used for allocation then they can be |
| * filled up again with minimal effort. The slab will never hit the |
| * per node partial lists and therefore no locking will be required. |
| * |
| * This setting also determines |
| * |
| * A) The number of objects from per cpu partial slabs dumped to the |
| * per node list when we reach the limit. |
| * B) The number of objects in cpu partial slabs to extract from the |
| * per node list when we run out of per cpu objects. We only fetch 50% |
| * to keep some capacity around for frees. |
| */ |
| if (s->size >= PAGE_SIZE) |
| s->cpu_partial = 2; |
| else if (s->size >= 1024) |
| s->cpu_partial = 6; |
| else if (s->size >= 256) |
| s->cpu_partial = 13; |
| else |
| s->cpu_partial = 30; |
| |
| s->refcount = 1; |
| #ifdef CONFIG_NUMA |
| s->remote_node_defrag_ratio = 1000; |
| #endif |
| if (!init_kmem_cache_nodes(s)) |
| goto error; |
| |
| if (alloc_kmem_cache_cpus(s)) |
| return 1; |
| |
| free_kmem_cache_nodes(s); |
| 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, oo_order(s->oo), |
| s->offset, flags); |
| return 0; |
| } |
| |
| /* |
| * Determine the size of a slab object |
| */ |
| unsigned int kmem_cache_size(struct kmem_cache *s) |
| { |
| return s->objsize; |
| } |
| EXPORT_SYMBOL(kmem_cache_size); |
| |
| static void list_slab_objects(struct kmem_cache *s, struct page *page, |
| const char *text) |
| { |
| #ifdef CONFIG_SLUB_DEBUG |
| void *addr = page_address(page); |
| void *p; |
| unsigned long *map = kzalloc(BITS_TO_LONGS(page->objects) * |
| sizeof(long), GFP_ATOMIC); |
| if (!map) |
| return; |
| slab_err(s, page, "%s", text); |
| slab_lock(page); |
| |
| get_map(s, page, map); |
| for_each_object(p, s, addr, page->objects) { |
| |
| if (!test_bit(slab_index(p, s, addr), map)) { |
| printk(KERN_ERR "INFO: Object 0x%p @offset=%tu\n", |
| p, p - addr); |
| print_tracking(s, p); |
| } |
| } |
| slab_unlock(page); |
| kfree(map); |
| #endif |
| } |
| |
| /* |
| * Attempt to free all partial slabs on a node. |
| * This is called from kmem_cache_close(). We must be the last thread |
| * using the cache and therefore we do not need to lock anymore. |
| */ |
| static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n) |
| { |
| struct page *page, *h; |
| |
| list_for_each_entry_safe(page, h, &n->partial, lru) { |
| if (!page->inuse) { |
| remove_partial(n, page); |
| discard_slab(s, page); |
| } else { |
| list_slab_objects(s, page, |
| "Objects remaining on kmem_cache_close()"); |
| } |
| } |
| } |
| |
| /* |
| * Release all resources used by a slab cache. |
| */ |
| static inline int kmem_cache_close(struct kmem_cache *s) |
| { |
| int node; |
| |
| flush_all(s); |
| free_percpu(s->cpu_slab); |
| /* Attempt to free all objects */ |
| for_each_node_state(node, N_NORMAL_MEMORY) { |
| struct kmem_cache_node *n = get_node(s, node); |
| |
| free_partial(s, n); |
| if (n->nr_partial || slabs_node(s, node)) |
| 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); |
| up_write(&slub_lock); |
| if (kmem_cache_close(s)) { |
| printk(KERN_ERR "SLUB %s: %s called for cache that " |
| "still has objects.\n", s->name, __func__); |
| dump_stack(); |
| } |
| if (s->flags & SLAB_DESTROY_BY_RCU) |
| rcu_barrier(); |
| sysfs_slab_remove(s); |
| } else |
| up_write(&slub_lock); |
| } |
| EXPORT_SYMBOL(kmem_cache_destroy); |
| |
| /******************************************************************** |
| * Kmalloc subsystem |
| *******************************************************************/ |
| |
| struct kmem_cache *kmalloc_caches[SLUB_PAGE_SHIFT]; |
| EXPORT_SYMBOL(kmalloc_caches); |
| |
| static struct kmem_cache *kmem_cache; |
| |
| #ifdef CONFIG_ZONE_DMA |
| static struct kmem_cache *kmalloc_dma_caches[SLUB_PAGE_SHIFT]; |
| #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); |
| slub_max_order = min(slub_max_order, MAX_ORDER - 1); |
| |
| return 1; |
| } |
| |
| __setup("slub_max_order=", setup_slub_max_order); |
| |
| static int __init setup_slub_min_objects(char *str) |
| { |
| get_option(&str |