288 lines
6.4 KiB
C
288 lines
6.4 KiB
C
/*
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* Slab allocator functions that are independent of the allocator strategy
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*
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* (C) 2012 Christoph Lameter <cl@linux.com>
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*/
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#include <linux/slab.h>
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#include <linux/mm.h>
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#include <linux/poison.h>
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#include <linux/interrupt.h>
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#include <linux/memory.h>
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#include <linux/compiler.h>
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#include <linux/module.h>
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#include <linux/cpu.h>
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#include <linux/uaccess.h>
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#include <linux/seq_file.h>
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#include <linux/proc_fs.h>
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#include <asm/cacheflush.h>
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#include <asm/tlbflush.h>
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#include <asm/page.h>
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#include "slab.h"
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enum slab_state slab_state;
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LIST_HEAD(slab_caches);
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DEFINE_MUTEX(slab_mutex);
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struct kmem_cache *kmem_cache;
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#ifdef CONFIG_DEBUG_VM
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static int kmem_cache_sanity_check(const char *name, size_t size)
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{
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struct kmem_cache *s = NULL;
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if (!name || in_interrupt() || size < sizeof(void *) ||
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size > KMALLOC_MAX_SIZE) {
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pr_err("kmem_cache_create(%s) integrity check failed\n", name);
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return -EINVAL;
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}
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list_for_each_entry(s, &slab_caches, list) {
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char tmp;
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int res;
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/*
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* This happens when the module gets unloaded and doesn't
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* destroy its slab cache and no-one else reuses the vmalloc
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* area of the module. Print a warning.
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*/
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res = probe_kernel_address(s->name, tmp);
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if (res) {
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pr_err("Slab cache with size %d has lost its name\n",
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s->object_size);
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continue;
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}
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if (!strcmp(s->name, name)) {
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pr_err("%s (%s): Cache name already exists.\n",
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__func__, name);
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dump_stack();
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s = NULL;
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return -EINVAL;
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}
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}
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WARN_ON(strchr(name, ' ')); /* It confuses parsers */
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return 0;
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}
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#else
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static inline int kmem_cache_sanity_check(const char *name, size_t size)
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{
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return 0;
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}
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#endif
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/*
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* kmem_cache_create - Create a cache.
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* @name: A string which is used in /proc/slabinfo to identify this cache.
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* @size: The size of objects to be created in this cache.
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* @align: The required alignment for the objects.
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* @flags: SLAB flags
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* @ctor: A constructor for the objects.
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*
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* Returns a ptr to the cache on success, NULL on failure.
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* Cannot be called within a interrupt, but can be interrupted.
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* The @ctor is run when new pages are allocated by the cache.
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*
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* The flags are
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*
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* %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
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* to catch references to uninitialised memory.
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*
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* %SLAB_RED_ZONE - Insert `Red' zones around the allocated memory to check
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* for buffer overruns.
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*
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* %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
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* cacheline. This can be beneficial if you're counting cycles as closely
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* as davem.
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*/
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struct kmem_cache *kmem_cache_create(const char *name, size_t size, size_t align,
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unsigned long flags, void (*ctor)(void *))
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{
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struct kmem_cache *s = NULL;
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int err = 0;
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get_online_cpus();
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mutex_lock(&slab_mutex);
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if (!kmem_cache_sanity_check(name, size) == 0)
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goto out_locked;
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s = __kmem_cache_alias(name, size, align, flags, ctor);
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if (s)
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goto out_locked;
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s = kmem_cache_zalloc(kmem_cache, GFP_KERNEL);
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if (s) {
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s->object_size = s->size = size;
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s->align = align;
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s->ctor = ctor;
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s->name = kstrdup(name, GFP_KERNEL);
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if (!s->name) {
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kmem_cache_free(kmem_cache, s);
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err = -ENOMEM;
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goto out_locked;
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}
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err = __kmem_cache_create(s, flags);
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if (!err) {
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s->refcount = 1;
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list_add(&s->list, &slab_caches);
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} else {
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kfree(s->name);
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kmem_cache_free(kmem_cache, s);
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}
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} else
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err = -ENOMEM;
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out_locked:
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mutex_unlock(&slab_mutex);
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put_online_cpus();
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if (err) {
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if (flags & SLAB_PANIC)
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panic("kmem_cache_create: Failed to create slab '%s'. Error %d\n",
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name, err);
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else {
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printk(KERN_WARNING "kmem_cache_create(%s) failed with error %d",
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name, err);
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dump_stack();
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}
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return NULL;
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}
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return s;
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}
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EXPORT_SYMBOL(kmem_cache_create);
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void kmem_cache_destroy(struct kmem_cache *s)
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{
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get_online_cpus();
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mutex_lock(&slab_mutex);
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s->refcount--;
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if (!s->refcount) {
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list_del(&s->list);
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if (!__kmem_cache_shutdown(s)) {
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mutex_unlock(&slab_mutex);
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if (s->flags & SLAB_DESTROY_BY_RCU)
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rcu_barrier();
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kfree(s->name);
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kmem_cache_free(kmem_cache, s);
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} else {
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list_add(&s->list, &slab_caches);
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mutex_unlock(&slab_mutex);
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printk(KERN_ERR "kmem_cache_destroy %s: Slab cache still has objects\n",
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s->name);
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dump_stack();
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}
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} else {
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mutex_unlock(&slab_mutex);
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}
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put_online_cpus();
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}
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EXPORT_SYMBOL(kmem_cache_destroy);
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int slab_is_available(void)
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{
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return slab_state >= UP;
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}
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#ifdef CONFIG_SLABINFO
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static void print_slabinfo_header(struct seq_file *m)
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{
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/*
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* Output format version, so at least we can change it
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* without _too_ many complaints.
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*/
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#ifdef CONFIG_DEBUG_SLAB
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seq_puts(m, "slabinfo - version: 2.1 (statistics)\n");
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#else
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seq_puts(m, "slabinfo - version: 2.1\n");
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#endif
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seq_puts(m, "# name <active_objs> <num_objs> <objsize> "
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"<objperslab> <pagesperslab>");
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seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>");
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seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>");
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#ifdef CONFIG_DEBUG_SLAB
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seq_puts(m, " : globalstat <listallocs> <maxobjs> <grown> <reaped> "
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"<error> <maxfreeable> <nodeallocs> <remotefrees> <alienoverflow>");
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seq_puts(m, " : cpustat <allochit> <allocmiss> <freehit> <freemiss>");
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#endif
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seq_putc(m, '\n');
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}
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static void *s_start(struct seq_file *m, loff_t *pos)
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{
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loff_t n = *pos;
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mutex_lock(&slab_mutex);
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if (!n)
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print_slabinfo_header(m);
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return seq_list_start(&slab_caches, *pos);
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}
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static void *s_next(struct seq_file *m, void *p, loff_t *pos)
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{
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return seq_list_next(p, &slab_caches, pos);
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}
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static void s_stop(struct seq_file *m, void *p)
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{
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mutex_unlock(&slab_mutex);
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}
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static int s_show(struct seq_file *m, void *p)
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{
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return slabinfo_show(m, p);
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}
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/*
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* slabinfo_op - iterator that generates /proc/slabinfo
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*
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* Output layout:
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* cache-name
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* num-active-objs
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* total-objs
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* object size
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* num-active-slabs
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* total-slabs
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* num-pages-per-slab
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* + further values on SMP and with statistics enabled
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*/
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static const struct seq_operations slabinfo_op = {
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.start = s_start,
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.next = s_next,
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.stop = s_stop,
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.show = s_show,
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};
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static int slabinfo_open(struct inode *inode, struct file *file)
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{
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return seq_open(file, &slabinfo_op);
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}
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static const struct file_operations proc_slabinfo_operations = {
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.open = slabinfo_open,
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.read = seq_read,
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.write = slabinfo_write,
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.llseek = seq_lseek,
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.release = seq_release,
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};
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static int __init slab_proc_init(void)
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{
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proc_create("slabinfo", S_IRUSR, NULL, &proc_slabinfo_operations);
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return 0;
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}
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module_init(slab_proc_init);
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#endif /* CONFIG_SLABINFO */
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