diff options
Diffstat (limited to 'mm/slab_common.c')
| -rw-r--r-- | mm/slab_common.c | 789 |
1 files changed, 789 insertions, 0 deletions
diff --git a/mm/slab_common.c b/mm/slab_common.c new file mode 100644 index 00000000000..d31c4bacc6a --- /dev/null +++ b/mm/slab_common.c @@ -0,0 +1,789 @@ +/* + * Slab allocator functions that are independent of the allocator strategy + * + * (C) 2012 Christoph Lameter <cl@linux.com> + */ +#include <linux/slab.h> + +#include <linux/mm.h> +#include <linux/poison.h> +#include <linux/interrupt.h> +#include <linux/memory.h> +#include <linux/compiler.h> +#include <linux/module.h> +#include <linux/cpu.h> +#include <linux/uaccess.h> +#include <linux/seq_file.h> +#include <linux/proc_fs.h> +#include <asm/cacheflush.h> +#include <asm/tlbflush.h> +#include <asm/page.h> +#include <linux/memcontrol.h> +#include <trace/events/kmem.h> + +#include "slab.h" + +enum slab_state slab_state; +LIST_HEAD(slab_caches); +DEFINE_MUTEX(slab_mutex); +struct kmem_cache *kmem_cache; + +#ifdef CONFIG_DEBUG_VM +static int kmem_cache_sanity_check(const char *name, size_t size) +{ + struct kmem_cache *s = NULL; + + if (!name || in_interrupt() || size < sizeof(void *) || + size > KMALLOC_MAX_SIZE) { + pr_err("kmem_cache_create(%s) integrity check failed\n", name); + return -EINVAL; + } + + list_for_each_entry(s, &slab_caches, list) { + char tmp; + int res; + + /* + * This happens when the module gets unloaded and doesn't + * destroy its slab cache and no-one else reuses the vmalloc + * area of the module. Print a warning. + */ + res = probe_kernel_address(s->name, tmp); + if (res) { + pr_err("Slab cache with size %d has lost its name\n", + s->object_size); + continue; + } + +#if !defined(CONFIG_SLUB) + if (!strcmp(s->name, name)) { + pr_err("%s (%s): Cache name already exists.\n", + __func__, name); + dump_stack(); + s = NULL; + return -EINVAL; + } +#endif + } + + WARN_ON(strchr(name, ' ')); /* It confuses parsers */ + return 0; +} +#else +static inline int kmem_cache_sanity_check(const char *name, size_t size) +{ + return 0; +} +#endif + +#ifdef CONFIG_MEMCG_KMEM +int memcg_update_all_caches(int num_memcgs) +{ + struct kmem_cache *s; + int ret = 0; + mutex_lock(&slab_mutex); + + list_for_each_entry(s, &slab_caches, list) { + if (!is_root_cache(s)) + continue; + + ret = memcg_update_cache_size(s, num_memcgs); + /* + * See comment in memcontrol.c, memcg_update_cache_size: + * Instead of freeing the memory, we'll just leave the caches + * up to this point in an updated state. + */ + if (ret) + goto out; + } + + memcg_update_array_size(num_memcgs); +out: + mutex_unlock(&slab_mutex); + return ret; +} +#endif + +/* + * Figure out what the alignment of the objects will be given a set of + * flags, a user specified alignment and the size of the objects. + */ +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 struct kmem_cache * +do_kmem_cache_create(char *name, size_t object_size, size_t size, size_t align, + unsigned long flags, void (*ctor)(void *), + struct mem_cgroup *memcg, struct kmem_cache *root_cache) +{ + struct kmem_cache *s; + int err; + + err = -ENOMEM; + s = kmem_cache_zalloc(kmem_cache, GFP_KERNEL); + if (!s) + goto out; + + s->name = name; + s->object_size = object_size; + s->size = size; + s->align = align; + s->ctor = ctor; + + err = memcg_alloc_cache_params(memcg, s, root_cache); + if (err) + goto out_free_cache; + + err = __kmem_cache_create(s, flags); + if (err) + goto out_free_cache; + + s->refcount = 1; + list_add(&s->list, &slab_caches); +out: + if (err) + return ERR_PTR(err); + return s; + +out_free_cache: + memcg_free_cache_params(s); + kfree(s); + goto out; +} + +/* + * kmem_cache_create - Create a cache. + * @name: A string which is used in /proc/slabinfo to identify this cache. + * @size: The size of objects to be created in this cache. + * @align: The required alignment for the objects. + * @flags: SLAB flags + * @ctor: A constructor for the objects. + * + * Returns a ptr to the cache on success, NULL on failure. + * Cannot be called within a interrupt, but can be interrupted. + * The @ctor is run when new pages are allocated by the cache. + * + * The flags are + * + * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5) + * to catch references to uninitialised memory. + * + * %SLAB_RED_ZONE - Insert `Red' zones around the allocated memory to check + * for buffer overruns. + * + * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware + * cacheline. This can be beneficial if you're counting cycles as closely + * as davem. + */ +struct kmem_cache * +kmem_cache_create(const char *name, size_t size, size_t align, + unsigned long flags, void (*ctor)(void *)) +{ + struct kmem_cache *s; + char *cache_name; + int err; + + get_online_cpus(); + get_online_mems(); + + mutex_lock(&slab_mutex); + + err = kmem_cache_sanity_check(name, size); + if (err) + goto out_unlock; + + /* + * Some allocators will constraint the set of valid flags to a subset + * of all flags. We expect them to define CACHE_CREATE_MASK in this + * case, and we'll just provide them with a sanitized version of the + * passed flags. + */ + flags &= CACHE_CREATE_MASK; + + s = __kmem_cache_alias(name, size, align, flags, ctor); + if (s) + goto out_unlock; + + cache_name = kstrdup(name, GFP_KERNEL); + if (!cache_name) { + err = -ENOMEM; + goto out_unlock; + } + + s = do_kmem_cache_create(cache_name, size, size, + calculate_alignment(flags, align, size), + flags, ctor, NULL, NULL); + if (IS_ERR(s)) { + err = PTR_ERR(s); + kfree(cache_name); + } + +out_unlock: + mutex_unlock(&slab_mutex); + + put_online_mems(); + put_online_cpus(); + + if (err) { + if (flags & SLAB_PANIC) + panic("kmem_cache_create: Failed to create slab '%s'. Error %d\n", + name, err); + else { + printk(KERN_WARNING "kmem_cache_create(%s) failed with error %d", + name, err); + dump_stack(); + } + return NULL; + } + return s; +} +EXPORT_SYMBOL(kmem_cache_create); + +#ifdef CONFIG_MEMCG_KMEM +/* + * memcg_create_kmem_cache - Create a cache for a memory cgroup. + * @memcg: The memory cgroup the new cache is for. + * @root_cache: The parent of the new cache. + * @memcg_name: The name of the memory cgroup (used for naming the new cache). + * + * This function attempts to create a kmem cache that will serve allocation + * requests going from @memcg to @root_cache. The new cache inherits properties + * from its parent. + */ +struct kmem_cache *memcg_create_kmem_cache(struct mem_cgroup *memcg, + struct kmem_cache *root_cache, + const char *memcg_name) +{ + struct kmem_cache *s = NULL; + char *cache_name; + + get_online_cpus(); + get_online_mems(); + + mutex_lock(&slab_mutex); + + cache_name = kasprintf(GFP_KERNEL, "%s(%d:%s)", root_cache->name, + memcg_cache_id(memcg), memcg_name); + if (!cache_name) + goto out_unlock; + + s = do_kmem_cache_create(cache_name, root_cache->object_size, + root_cache->size, root_cache->align, + root_cache->flags, root_cache->ctor, + memcg, root_cache); + if (IS_ERR(s)) { + kfree(cache_name); + s = NULL; + } + +out_unlock: + mutex_unlock(&slab_mutex); + + put_online_mems(); + put_online_cpus(); + + return s; +} + +static int memcg_cleanup_cache_params(struct kmem_cache *s) +{ + int rc; + + if (!s->memcg_params || + !s->memcg_params->is_root_cache) + return 0; + + mutex_unlock(&slab_mutex); + rc = __memcg_cleanup_cache_params(s); + mutex_lock(&slab_mutex); + + return rc; +} +#else +static int memcg_cleanup_cache_params(struct kmem_cache *s) +{ + return 0; +} +#endif /* CONFIG_MEMCG_KMEM */ + +void slab_kmem_cache_release(struct kmem_cache *s) +{ + kfree(s->name); + kmem_cache_free(kmem_cache, s); +} + +void kmem_cache_destroy(struct kmem_cache *s) +{ + get_online_cpus(); + get_online_mems(); + + mutex_lock(&slab_mutex); + + s->refcount--; + if (s->refcount) + goto out_unlock; + + if (memcg_cleanup_cache_params(s) != 0) + goto out_unlock; + + if (__kmem_cache_shutdown(s) != 0) { + printk(KERN_ERR "kmem_cache_destroy %s: " + "Slab cache still has objects\n", s->name); + dump_stack(); + goto out_unlock; + } + + list_del(&s->list); + + mutex_unlock(&slab_mutex); + if (s->flags & SLAB_DESTROY_BY_RCU) + rcu_barrier(); + + memcg_free_cache_params(s); +#ifdef SLAB_SUPPORTS_SYSFS + sysfs_slab_remove(s); +#else + slab_kmem_cache_release(s); +#endif + goto out; + +out_unlock: + mutex_unlock(&slab_mutex); +out: + put_online_mems(); + put_online_cpus(); +} +EXPORT_SYMBOL(kmem_cache_destroy); + +/** + * kmem_cache_shrink - Shrink a cache. + * @cachep: The cache to shrink. + * + * Releases as many slabs as possible for a cache. + * To help debugging, a zero exit status indicates all slabs were released. + */ +int kmem_cache_shrink(struct kmem_cache *cachep) +{ + int ret; + + get_online_cpus(); + get_online_mems(); + ret = __kmem_cache_shrink(cachep); + put_online_mems(); + put_online_cpus(); + return ret; +} +EXPORT_SYMBOL(kmem_cache_shrink); + +int slab_is_available(void) +{ + return slab_state >= UP; +} + +#ifndef CONFIG_SLOB +/* Create a cache during boot when no slab services are available yet */ +void __init create_boot_cache(struct kmem_cache *s, const char *name, size_t size, + unsigned long flags) +{ + int err; + + s->name = name; + s->size = s->object_size = size; + s->align = calculate_alignment(flags, ARCH_KMALLOC_MINALIGN, size); + err = __kmem_cache_create(s, flags); + + if (err) + panic("Creation of kmalloc slab %s size=%zu failed. Reason %d\n", + name, size, err); + + s->refcount = -1; /* Exempt from merging for now */ +} + +struct kmem_cache *__init create_kmalloc_cache(const char *name, size_t size, + unsigned long flags) +{ + struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT); + + if (!s) + panic("Out of memory when creating slab %s\n", name); + + create_boot_cache(s, name, size, flags); + list_add(&s->list, &slab_caches); + s->refcount = 1; + return s; +} + +struct kmem_cache *kmalloc_caches[KMALLOC_SHIFT_HIGH + 1]; +EXPORT_SYMBOL(kmalloc_caches); + +#ifdef CONFIG_ZONE_DMA +struct kmem_cache *kmalloc_dma_caches[KMALLOC_SHIFT_HIGH + 1]; +EXPORT_SYMBOL(kmalloc_dma_caches); +#endif + +/* + * Conversion table for small slabs sizes / 8 to the index in the + * kmalloc array. This is necessary for slabs < 192 since we have non power + * of two cache sizes there. The size of larger slabs can be determined using + * fls. + */ +static s8 size_index[24] = { + 3, /* 8 */ + 4, /* 16 */ + 5, /* 24 */ + 5, /* 32 */ + 6, /* 40 */ + 6, /* 48 */ + 6, /* 56 */ + 6, /* 64 */ + 1, /* 72 */ + 1, /* 80 */ + 1, /* 88 */ + 1, /* 96 */ + 7, /* 104 */ + 7, /* 112 */ + 7, /* 120 */ + 7, /* 128 */ + 2, /* 136 */ + 2, /* 144 */ + 2, /* 152 */ + 2, /* 160 */ + 2, /* 168 */ + 2, /* 176 */ + 2, /* 184 */ + 2 /* 192 */ +}; + +static inline int size_index_elem(size_t bytes) +{ + return (bytes - 1) / 8; +} + +/* + * Find the kmem_cache structure that serves a given size of + * allocation + */ +struct kmem_cache *kmalloc_slab(size_t size, gfp_t flags) +{ + int index; + + if (unlikely(size > KMALLOC_MAX_SIZE)) { + WARN_ON_ONCE(!(flags & __GFP_NOWARN)); + return NULL; + } + + if (size <= 192) { + if (!size) + return ZERO_SIZE_PTR; + + index = size_index[size_index_elem(size)]; + } else + index = fls(size - 1); + +#ifdef CONFIG_ZONE_DMA + if (unlikely((flags & GFP_DMA))) + return kmalloc_dma_caches[index]; + +#endif + return kmalloc_caches[index]; +} + +/* + * Create the kmalloc array. Some of the regular kmalloc arrays + * may already have been created because they were needed to + * enable allocations for slab creation. + */ +void __init create_kmalloc_caches(unsigned long flags) +{ + int i; + + /* + * Patch up the size_index table if we have strange large alignment + * requirements for the kmalloc array. This is only the case for + * MIPS it seems. The standard arches will not generate any code here. + * + * Largest permitted alignment is 256 bytes due to the way we + * handle the index determination for the smaller caches. + * + * Make sure that nothing crazy happens if someone starts tinkering + * around with ARCH_KMALLOC_MINALIGN + */ + BUILD_BUG_ON(KMALLOC_MIN_SIZE > 256 || + (KMALLOC_MIN_SIZE & (KMALLOC_MIN_SIZE - 1))); + + for (i = 8; i < KMALLOC_MIN_SIZE; i += 8) { + int elem = size_index_elem(i); + + if (elem >= ARRAY_SIZE(size_index)) + break; + size_index[elem] = KMALLOC_SHIFT_LOW; + } + + if (KMALLOC_MIN_SIZE >= 64) { + /* + * The 96 byte size cache is not used if the alignment + * is 64 byte. + */ + for (i = 64 + 8; i <= 96; i += 8) + size_index[size_index_elem(i)] = 7; + + } + + if (KMALLOC_MIN_SIZE >= 128) { + /* + * The 192 byte sized cache is not used if the alignment + * is 128 byte. Redirect kmalloc to use the 256 byte cache + * instead. + */ + for (i = 128 + 8; i <= 192; i += 8) + size_index[size_index_elem(i)] = 8; + } + for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++) { + if (!kmalloc_caches[i]) { + kmalloc_caches[i] = create_kmalloc_cache(NULL, + 1 << i, flags); + } + + /* + * Caches that are not of the two-to-the-power-of size. + * These have to be created immediately after the + * earlier power of two caches + */ + if (KMALLOC_MIN_SIZE <= 32 && !kmalloc_caches[1] && i == 6) + kmalloc_caches[1] = create_kmalloc_cache(NULL, 96, flags); + + if (KMALLOC_MIN_SIZE <= 64 && !kmalloc_caches[2] && i == 7) + kmalloc_caches[2] = create_kmalloc_cache(NULL, 192, flags); + } + + /* Kmalloc array is now usable */ + slab_state = UP; + + for (i = 0; i <= KMALLOC_SHIFT_HIGH; i++) { + struct kmem_cache *s = kmalloc_caches[i]; + char *n; + + if (s) { + n = kasprintf(GFP_NOWAIT, "kmalloc-%d", kmalloc_size(i)); + + BUG_ON(!n); + s->name = n; + } + } + +#ifdef CONFIG_ZONE_DMA + for (i = 0; i <= KMALLOC_SHIFT_HIGH; i++) { + struct kmem_cache *s = kmalloc_caches[i]; + + if (s) { + int size = kmalloc_size(i); + char *n = kasprintf(GFP_NOWAIT, + "dma-kmalloc-%d", size); + + BUG_ON(!n); + kmalloc_dma_caches[i] = create_kmalloc_cache(n, + size, SLAB_CACHE_DMA | flags); + } + } +#endif +} +#endif /* !CONFIG_SLOB */ + +/* + * To avoid unnecessary overhead, we pass through large allocation requests + * directly to the page allocator. We use __GFP_COMP, because we will need to + * know the allocation order to free the pages properly in kfree. + */ +void *kmalloc_order(size_t size, gfp_t flags, unsigned int order) +{ + void *ret; + struct page *page; + + flags |= __GFP_COMP; + page = alloc_kmem_pages(flags, order); + ret = page ? page_address(page) : NULL; + kmemleak_alloc(ret, size, 1, flags); + return ret; +} +EXPORT_SYMBOL(kmalloc_order); + +#ifdef CONFIG_TRACING +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_SLABINFO + +#ifdef CONFIG_SLAB +#define SLABINFO_RIGHTS (S_IWUSR | S_IRUSR) +#else +#define SLABINFO_RIGHTS S_IRUSR +#endif + +void print_slabinfo_header(struct seq_file *m) +{ + /* + * Output format version, so at least we can change it + * without _too_ many complaints. + */ +#ifdef CONFIG_DEBUG_SLAB + seq_puts(m, "slabinfo - version: 2.1 (statistics)\n"); +#else + seq_puts(m, "slabinfo - version: 2.1\n"); +#endif + seq_puts(m, "# name <active_objs> <num_objs> <objsize> " + "<objperslab> <pagesperslab>"); + seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>"); + seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>"); +#ifdef CONFIG_DEBUG_SLAB + seq_puts(m, " : globalstat <listallocs> <maxobjs> <grown> <reaped> " + "<error> <maxfreeable> <nodeallocs> <remotefrees> <alienoverflow>"); + seq_puts(m, " : cpustat <allochit> <allocmiss> <freehit> <freemiss>"); +#endif + seq_putc(m, '\n'); +} + +static void *s_start(struct seq_file *m, loff_t *pos) +{ + loff_t n = *pos; + + mutex_lock(&slab_mutex); + if (!n) + print_slabinfo_header(m); + + return seq_list_start(&slab_caches, *pos); +} + +void *slab_next(struct seq_file *m, void *p, loff_t *pos) +{ + return seq_list_next(p, &slab_caches, pos); +} + +void slab_stop(struct seq_file *m, void *p) +{ + mutex_unlock(&slab_mutex); +} + +static void +memcg_accumulate_slabinfo(struct kmem_cache *s, struct slabinfo *info) +{ + struct kmem_cache *c; + struct slabinfo sinfo; + int i; + + if (!is_root_cache(s)) + return; + + for_each_memcg_cache_index(i) { + c = cache_from_memcg_idx(s, i); + if (!c) + continue; + + memset(&sinfo, 0, sizeof(sinfo)); + get_slabinfo(c, &sinfo); + + info->active_slabs += sinfo.active_slabs; + info->num_slabs += sinfo.num_slabs; + info->shared_avail += sinfo.shared_avail; + info->active_objs += sinfo.active_objs; + info->num_objs += sinfo.num_objs; + } +} + +int cache_show(struct kmem_cache *s, struct seq_file *m) +{ + struct slabinfo sinfo; + + memset(&sinfo, 0, sizeof(sinfo)); + get_slabinfo(s, &sinfo); + + memcg_accumulate_slabinfo(s, &sinfo); + + seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d", + cache_name(s), sinfo.active_objs, sinfo.num_objs, s->size, + sinfo.objects_per_slab, (1 << sinfo.cache_order)); + + seq_printf(m, " : tunables %4u %4u %4u", + sinfo.limit, sinfo.batchcount, sinfo.shared); + seq_printf(m, " : slabdata %6lu %6lu %6lu", + sinfo.active_slabs, sinfo.num_slabs, sinfo.shared_avail); + slabinfo_show_stats(m, s); + seq_putc(m, '\n'); + return 0; +} + +static int s_show(struct seq_file *m, void *p) +{ + struct kmem_cache *s = list_entry(p, struct kmem_cache, list); + + if (!is_root_cache(s)) + return 0; + return cache_show(s, m); +} + +/* + * slabinfo_op - iterator that generates /proc/slabinfo + * + * Output layout: + * cache-name + * num-active-objs + * total-objs + * object size + * num-active-slabs + * total-slabs + * num-pages-per-slab + * + further values on SMP and with statistics enabled + */ +static const struct seq_operations slabinfo_op = { + .start = s_start, + .next = slab_next, + .stop = slab_stop, + .show = s_show, +}; + +static int slabinfo_open(struct inode *inode, struct file *file) +{ + return seq_open(file, &slabinfo_op); +} + +static const struct file_operations proc_slabinfo_operations = { + .open = slabinfo_open, + .read = seq_read, + .write = slabinfo_write, + .llseek = seq_lseek, + .release = seq_release, +}; + +static int __init slab_proc_init(void) +{ + proc_create("slabinfo", SLABINFO_RIGHTS, NULL, + &proc_slabinfo_operations); + return 0; +} +module_init(slab_proc_init); +#endif /* CONFIG_SLABINFO */ |