mm/slab_common.c

   1 /*
   2  * Slab allocator functions that are independent of the allocator strategy
   3  *
   4  * (C) 2012 Christoph Lameter <cl@linux.com>
   5  */
   6 #include <linux/slab.h>
   7
   8 #include <linux/mm.h>
   9 #include <linux/poison.h>
  10 #include <linux/interrupt.h>
  11 #include <linux/memory.h>
  12 #include <linux/compiler.h>
  13 #include <linux/module.h>
  14 #include <linux/cpu.h>
  15 #include <linux/uaccess.h>
  16 #include <asm/cacheflush.h>
  17 #include <asm/tlbflush.h>
  18 #include <asm/page.h>
  19
  20 #include "slab.h"
  21
  22 enum slab_state slab_state;
  23 LIST_HEAD(slab_caches);
  24 DEFINE_MUTEX(slab_mutex);
  25
  26 /*
  27  * kmem_cache_create - Create a cache.
  28  * @name: A string which is used in /proc/slabinfo to identify this cache.
  29  * @size: The size of objects to be created in this cache.
  30  * @align: The required alignment for the objects.
  31  * @flags: SLAB flags
  32  * @ctor: A constructor for the objects.
  33  *
  34  * Returns a ptr to the cache on success, NULL on failure.
  35  * Cannot be called within a interrupt, but can be interrupted.
  36  * The @ctor is run when new pages are allocated by the cache.
  37  *
  38  * The flags are
  39  *
  40  * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
  41  * to catch references to uninitialised memory.
  42  *
  43  * %SLAB_RED_ZONE - Insert `Red' zones around the allocated memory to check
  44  * for buffer overruns.
  45  *
  46  * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
  47  * cacheline.  This can be beneficial if you're counting cycles as closely
  48  * as davem.
  49  */
  50
  51 struct kmem_cache *kmem_cache_create(const char *name, size_t size, size_t align,
  52                 unsigned long flags, void (*ctor)(void *))
  53 {
  54         struct kmem_cache *s = NULL;
  55
  56         get_online_cpus();
  57         mutex_lock(&slab_mutex);
  58
  59 #ifdef CONFIG_DEBUG_VM
  60         if (!name || in_interrupt() || size < sizeof(void *) ||
  61                 size > KMALLOC_MAX_SIZE) {
  62                 printk(KERN_ERR "kmem_cache_create(%s) integrity check"
  63                                 " failed\n", name);
  64                 goto oops;
  65         }
  66
  67         list_for_each_entry(s, &slab_caches, list) {
  68                 char tmp;
  69                 int res;
  70
  71                 /*
  72                  * This happens when the module gets unloaded and doesn't
  73                  * destroy its slab cache and no-one else reuses the vmalloc
  74                  * area of the module.  Print a warning.
  75                  */
  76                 res = probe_kernel_address(s->name, tmp);
  77                 if (res) {
  78                         printk(KERN_ERR
  79                                "Slab cache with size %d has lost its name\n",
  80                                s->object_size);
  81                         continue;
  82                 }
  83
  84                 if (!strcmp(s->name, name)) {
  85                         printk(KERN_ERR "kmem_cache_create(%s): Cache name"
  86                                 " already exists.\n",
  87                                 name);
  88                         dump_stack();
  89                         s = NULL;
  90                         goto oops;
  91                 }
  92         }
  93
  94         WARN_ON(strchr(name, ' '));     /* It confuses parsers */
  95 #endif
  96
  97         s = __kmem_cache_create(name, size, align, flags, ctor);
  98
  99 #ifdef CONFIG_DEBUG_VM
 100 oops:
 101 #endif
 102         mutex_unlock(&slab_mutex);
 103         put_online_cpus();
 104
 105         if (!s && (flags & SLAB_PANIC))
 106                 panic("kmem_cache_create: Failed to create slab '%s'\n", name);
 107
 108         return s;
 109 }
 110 EXPORT_SYMBOL(kmem_cache_create);
 111
 112 int slab_is_available(void)
 113 {
 114         return slab_state >= UP;
 115 }