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 #ifdef CONFIG_DEBUG_VM
  57         if (!name || in_interrupt() || size < sizeof(void *) ||
  58                 size > KMALLOC_MAX_SIZE) {
  59                 printk(KERN_ERR "kmem_cache_create(%s) integrity check"
  60                         " failed\n", name);
  61                 goto out;
  62         }
  63 #endif
  64
  65         get_online_cpus();
  66         mutex_lock(&slab_mutex);
  67
  68 #ifdef CONFIG_DEBUG_VM
  69         list_for_each_entry(s, &slab_caches, list) {
  70                 char tmp;
  71                 int res;
  72
  73                 /*
  74                  * This happens when the module gets unloaded and doesn't
  75                  * destroy its slab cache and no-one else reuses the vmalloc
  76                  * area of the module.  Print a warning.
  77                  */
  78                 res = probe_kernel_address(s->name, tmp);
  79                 if (res) {
  80                         printk(KERN_ERR
  81                                "Slab cache with size %d has lost its name\n",
  82                                s->object_size);
  83                         continue;
  84                 }
  85
  86                 if (!strcmp(s->name, name)) {
  87                         printk(KERN_ERR "kmem_cache_create(%s): Cache name"
  88                                 " already exists.\n",
  89                                 name);
  90                         dump_stack();
  91                         s = NULL;
  92                         goto oops;
  93                 }
  94         }
  95
  96         WARN_ON(strchr(name, ' '));     /* It confuses parsers */
  97 #endif
  98
  99         s = __kmem_cache_create(name, size, align, flags, ctor);
 100
 101 #ifdef CONFIG_DEBUG_VM
 102 oops:
 103 #endif
 104         mutex_unlock(&slab_mutex);
 105         put_online_cpus();
 106
 107 #ifdef CONFIG_DEBUG_VM
 108 out:
 109 #endif
 110         if (!s && (flags & SLAB_PANIC))
 111                 panic("kmem_cache_create: Failed to create slab '%s'\n", name);
 112
 113         return s;
 114 }
 115 EXPORT_SYMBOL(kmem_cache_create);
 116
 117 int slab_is_available(void)
 118 {
 119         return slab_state >= UP;
 120 }