467 lines
11 KiB
C
467 lines
11 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 <linux/memcontrol.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(struct mem_cgroup *memcg, const char *name,
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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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/*
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* For simplicity, we won't check this in the list of memcg
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* caches. We have control over memcg naming, and if there
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* aren't duplicates in the global list, there won't be any
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* duplicates in the memcg lists as well.
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*/
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if (!memcg && !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(struct mem_cgroup *memcg,
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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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#ifdef CONFIG_MEMCG_KMEM
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int memcg_update_all_caches(int num_memcgs)
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{
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struct kmem_cache *s;
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int ret = 0;
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mutex_lock(&slab_mutex);
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list_for_each_entry(s, &slab_caches, list) {
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if (!is_root_cache(s))
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continue;
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ret = memcg_update_cache_size(s, num_memcgs);
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/*
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* See comment in memcontrol.c, memcg_update_cache_size:
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* Instead of freeing the memory, we'll just leave the caches
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* up to this point in an updated state.
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*/
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if (ret)
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goto out;
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}
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memcg_update_array_size(num_memcgs);
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out:
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mutex_unlock(&slab_mutex);
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return ret;
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}
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#endif
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/*
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* Figure out what the alignment of the objects will be given a set of
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* flags, a user specified alignment and the size of the objects.
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*/
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unsigned long calculate_alignment(unsigned long flags,
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unsigned long align, unsigned long size)
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{
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/*
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* If the user wants hardware cache aligned objects then follow that
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* suggestion if the object is sufficiently large.
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*
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* The hardware cache alignment cannot override the specified
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* alignment though. If that is greater then use it.
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*/
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if (flags & SLAB_HWCACHE_ALIGN) {
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unsigned long ralign = cache_line_size();
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while (size <= ralign / 2)
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ralign /= 2;
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align = max(align, ralign);
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}
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if (align < ARCH_SLAB_MINALIGN)
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align = ARCH_SLAB_MINALIGN;
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return ALIGN(align, sizeof(void *));
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}
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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 *
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kmem_cache_create_memcg(struct mem_cgroup *memcg, const char *name, size_t size,
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size_t align, unsigned long flags, void (*ctor)(void *),
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struct kmem_cache *parent_cache)
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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(memcg, name, size) == 0)
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goto out_locked;
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/*
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* Some allocators will constraint the set of valid flags to a subset
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* of all flags. We expect them to define CACHE_CREATE_MASK in this
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* case, and we'll just provide them with a sanitized version of the
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* passed flags.
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*/
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flags &= CACHE_CREATE_MASK;
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s = __kmem_cache_alias(memcg, 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 = calculate_alignment(flags, align, size);
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s->ctor = ctor;
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if (memcg_register_cache(memcg, s, parent_cache)) {
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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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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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memcg_cache_list_add(memcg, s);
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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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struct kmem_cache *
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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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return kmem_cache_create_memcg(NULL, name, size, align, flags, ctor, NULL);
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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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/* Destroy all the children caches if we aren't a memcg cache */
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kmem_cache_destroy_memcg_children(s);
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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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memcg_release_cache(s);
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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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#ifndef CONFIG_SLOB
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/* Create a cache during boot when no slab services are available yet */
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void __init create_boot_cache(struct kmem_cache *s, const char *name, size_t size,
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unsigned long flags)
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{
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int err;
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s->name = name;
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s->size = s->object_size = size;
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s->align = calculate_alignment(flags, ARCH_KMALLOC_MINALIGN, size);
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err = __kmem_cache_create(s, flags);
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if (err)
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panic("Creation of kmalloc slab %s size=%zu failed. Reason %d\n",
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name, size, err);
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s->refcount = -1; /* Exempt from merging for now */
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}
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struct kmem_cache *__init create_kmalloc_cache(const char *name, size_t size,
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unsigned long flags)
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{
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struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
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if (!s)
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panic("Out of memory when creating slab %s\n", name);
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create_boot_cache(s, name, size, flags);
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list_add(&s->list, &slab_caches);
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s->refcount = 1;
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return s;
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}
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#endif /* !CONFIG_SLOB */
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#ifdef CONFIG_SLABINFO
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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 void
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memcg_accumulate_slabinfo(struct kmem_cache *s, struct slabinfo *info)
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{
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struct kmem_cache *c;
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struct slabinfo sinfo;
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int i;
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if (!is_root_cache(s))
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return;
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for_each_memcg_cache_index(i) {
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c = cache_from_memcg(s, i);
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if (!c)
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continue;
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memset(&sinfo, 0, sizeof(sinfo));
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get_slabinfo(c, &sinfo);
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info->active_slabs += sinfo.active_slabs;
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info->num_slabs += sinfo.num_slabs;
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info->shared_avail += sinfo.shared_avail;
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info->active_objs += sinfo.active_objs;
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info->num_objs += sinfo.num_objs;
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}
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}
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int cache_show(struct kmem_cache *s, struct seq_file *m)
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{
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struct slabinfo sinfo;
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memset(&sinfo, 0, sizeof(sinfo));
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get_slabinfo(s, &sinfo);
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memcg_accumulate_slabinfo(s, &sinfo);
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seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d",
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cache_name(s), sinfo.active_objs, sinfo.num_objs, s->size,
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sinfo.objects_per_slab, (1 << sinfo.cache_order));
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seq_printf(m, " : tunables %4u %4u %4u",
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sinfo.limit, sinfo.batchcount, sinfo.shared);
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seq_printf(m, " : slabdata %6lu %6lu %6lu",
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sinfo.active_slabs, sinfo.num_slabs, sinfo.shared_avail);
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slabinfo_show_stats(m, s);
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seq_putc(m, '\n');
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return 0;
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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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struct kmem_cache *s = list_entry(p, struct kmem_cache, list);
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if (!is_root_cache(s))
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return 0;
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return cache_show(s, m);
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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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