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Diffstat (limited to 'mm/slab.c')
| -rw-r--r-- | mm/slab.c | 4201 |
1 files changed, 4201 insertions, 0 deletions
diff --git a/mm/slab.c b/mm/slab.c new file mode 100644 index 000000000..b2cc2cf7d --- /dev/null +++ b/mm/slab.c @@ -0,0 +1,4201 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * linux/mm/slab.c + * Written by Mark Hemment, 1996/97. + * (markhe@nextd.demon.co.uk) + * + * kmem_cache_destroy() + some cleanup - 1999 Andrea Arcangeli + * + * Major cleanup, different bufctl logic, per-cpu arrays + * (c) 2000 Manfred Spraul + * + * Cleanup, make the head arrays unconditional, preparation for NUMA + * (c) 2002 Manfred Spraul + * + * An implementation of the Slab Allocator as described in outline in; + * UNIX Internals: The New Frontiers by Uresh Vahalia + * Pub: Prentice Hall ISBN 0-13-101908-2 + * or with a little more detail in; + * The Slab Allocator: An Object-Caching Kernel Memory Allocator + * Jeff Bonwick (Sun Microsystems). + * Presented at: USENIX Summer 1994 Technical Conference + * + * The memory is organized in caches, one cache for each object type. + * (e.g. inode_cache, dentry_cache, buffer_head, vm_area_struct) + * Each cache consists out of many slabs (they are small (usually one + * page long) and always contiguous), and each slab contains multiple + * initialized objects. + * + * This means, that your constructor is used only for newly allocated + * slabs and you must pass objects with the same initializations to + * kmem_cache_free. + * + * Each cache can only support one memory type (GFP_DMA, GFP_HIGHMEM, + * normal). If you need a special memory type, then must create a new + * cache for that memory type. + * + * In order to reduce fragmentation, the slabs are sorted in 3 groups: + * full slabs with 0 free objects + * partial slabs + * empty slabs with no allocated objects + * + * If partial slabs exist, then new allocations come from these slabs, + * otherwise from empty slabs or new slabs are allocated. + * + * kmem_cache_destroy() CAN CRASH if you try to allocate from the cache + * during kmem_cache_destroy(). The caller must prevent concurrent allocs. + * + * Each cache has a short per-cpu head array, most allocs + * and frees go into that array, and if that array overflows, then 1/2 + * of the entries in the array are given back into the global cache. + * The head array is strictly LIFO and should improve the cache hit rates. + * On SMP, it additionally reduces the spinlock operations. + * + * The c_cpuarray may not be read with enabled local interrupts - + * it's changed with a smp_call_function(). + * + * SMP synchronization: + * constructors and destructors are called without any locking. + * Several members in struct kmem_cache and struct slab never change, they + * are accessed without any locking. + * The per-cpu arrays are never accessed from the wrong cpu, no locking, + * and local interrupts are disabled so slab code is preempt-safe. + * The non-constant members are protected with a per-cache irq spinlock. + * + * Many thanks to Mark Hemment, who wrote another per-cpu slab patch + * in 2000 - many ideas in the current implementation are derived from + * his patch. + * + * Further notes from the original documentation: + * + * 11 April '97. Started multi-threading - markhe + * The global cache-chain is protected by the mutex 'slab_mutex'. + * The sem is only needed when accessing/extending the cache-chain, which + * can never happen inside an interrupt (kmem_cache_create(), + * kmem_cache_shrink() and kmem_cache_reap()). + * + * At present, each engine can be growing a cache. This should be blocked. + * + * 15 March 2005. NUMA slab allocator. + * Shai Fultheim <shai@scalex86.org>. + * Shobhit Dayal <shobhit@calsoftinc.com> + * Alok N Kataria <alokk@calsoftinc.com> + * Christoph Lameter <christoph@lameter.com> + * + * Modified the slab allocator to be node aware on NUMA systems. + * Each node has its own list of partial, free and full slabs. + * All object allocations for a node occur from node specific slab lists. + */ + +#include <linux/slab.h> +#include <linux/mm.h> +#include <linux/poison.h> +#include <linux/swap.h> +#include <linux/cache.h> +#include <linux/interrupt.h> +#include <linux/init.h> +#include <linux/compiler.h> +#include <linux/cpuset.h> +#include <linux/proc_fs.h> +#include <linux/seq_file.h> +#include <linux/notifier.h> +#include <linux/kallsyms.h> +#include <linux/cpu.h> +#include <linux/sysctl.h> +#include <linux/module.h> +#include <linux/rcupdate.h> +#include <linux/string.h> +#include <linux/uaccess.h> +#include <linux/nodemask.h> +#include <linux/kmemleak.h> +#include <linux/mempolicy.h> +#include <linux/mutex.h> +#include <linux/fault-inject.h> +#include <linux/rtmutex.h> +#include <linux/reciprocal_div.h> +#include <linux/debugobjects.h> +#include <linux/memory.h> +#include <linux/prefetch.h> +#include <linux/sched/task_stack.h> + +#include <net/sock.h> + +#include <asm/cacheflush.h> +#include <asm/tlbflush.h> +#include <asm/page.h> + +#include <trace/events/kmem.h> + +#include "internal.h" + +#include "slab.h" + +/* + * DEBUG - 1 for kmem_cache_create() to honour; SLAB_RED_ZONE & SLAB_POISON. + * 0 for faster, smaller code (especially in the critical paths). + * + * STATS - 1 to collect stats for /proc/slabinfo. + * 0 for faster, smaller code (especially in the critical paths). + * + * FORCED_DEBUG - 1 enables SLAB_RED_ZONE and SLAB_POISON (if possible) + */ + +#ifdef CONFIG_DEBUG_SLAB +#define DEBUG 1 +#define STATS 1 +#define FORCED_DEBUG 1 +#else +#define DEBUG 0 +#define STATS 0 +#define FORCED_DEBUG 0 +#endif + +/* Shouldn't this be in a header file somewhere? */ +#define BYTES_PER_WORD sizeof(void *) +#define REDZONE_ALIGN max(BYTES_PER_WORD, __alignof__(unsigned long long)) + +#ifndef ARCH_KMALLOC_FLAGS +#define ARCH_KMALLOC_FLAGS SLAB_HWCACHE_ALIGN +#endif + +#define FREELIST_BYTE_INDEX (((PAGE_SIZE >> BITS_PER_BYTE) \ + <= SLAB_OBJ_MIN_SIZE) ? 1 : 0) + +#if FREELIST_BYTE_INDEX +typedef unsigned char freelist_idx_t; +#else +typedef unsigned short freelist_idx_t; +#endif + +#define SLAB_OBJ_MAX_NUM ((1 << sizeof(freelist_idx_t) * BITS_PER_BYTE) - 1) + +/* + * struct array_cache + * + * Purpose: + * - LIFO ordering, to hand out cache-warm objects from _alloc + * - reduce the number of linked list operations + * - reduce spinlock operations + * + * The limit is stored in the per-cpu structure to reduce the data cache + * footprint. + * + */ +struct array_cache { + unsigned int avail; + unsigned int limit; + unsigned int batchcount; + unsigned int touched; + void *entry[]; /* + * Must have this definition in here for the proper + * alignment of array_cache. Also simplifies accessing + * the entries. + */ +}; + +struct alien_cache { + spinlock_t lock; + struct array_cache ac; +}; + +/* + * Need this for bootstrapping a per node allocator. + */ +#define NUM_INIT_LISTS (2 * MAX_NUMNODES) +static struct kmem_cache_node __initdata init_kmem_cache_node[NUM_INIT_LISTS]; +#define CACHE_CACHE 0 +#define SIZE_NODE (MAX_NUMNODES) + +static int drain_freelist(struct kmem_cache *cache, + struct kmem_cache_node *n, int tofree); +static void free_block(struct kmem_cache *cachep, void **objpp, int len, + int node, struct list_head *list); +static void slabs_destroy(struct kmem_cache *cachep, struct list_head *list); +static int enable_cpucache(struct kmem_cache *cachep, gfp_t gfp); +static void cache_reap(struct work_struct *unused); + +static inline void fixup_objfreelist_debug(struct kmem_cache *cachep, + void **list); +static inline void fixup_slab_list(struct kmem_cache *cachep, + struct kmem_cache_node *n, struct page *page, + void **list); +static int slab_early_init = 1; + +#define INDEX_NODE kmalloc_index(sizeof(struct kmem_cache_node)) + +static void kmem_cache_node_init(struct kmem_cache_node *parent) +{ + INIT_LIST_HEAD(&parent->slabs_full); + INIT_LIST_HEAD(&parent->slabs_partial); + INIT_LIST_HEAD(&parent->slabs_free); + parent->total_slabs = 0; + parent->free_slabs = 0; + parent->shared = NULL; + parent->alien = NULL; + parent->colour_next = 0; + spin_lock_init(&parent->list_lock); + parent->free_objects = 0; + parent->free_touched = 0; +} + +#define MAKE_LIST(cachep, listp, slab, nodeid) \ + do { \ + INIT_LIST_HEAD(listp); \ + list_splice(&get_node(cachep, nodeid)->slab, listp); \ + } while (0) + +#define MAKE_ALL_LISTS(cachep, ptr, nodeid) \ + do { \ + MAKE_LIST((cachep), (&(ptr)->slabs_full), slabs_full, nodeid); \ + MAKE_LIST((cachep), (&(ptr)->slabs_partial), slabs_partial, nodeid); \ + MAKE_LIST((cachep), (&(ptr)->slabs_free), slabs_free, nodeid); \ + } while (0) + +#define CFLGS_OBJFREELIST_SLAB ((slab_flags_t __force)0x40000000U) +#define CFLGS_OFF_SLAB ((slab_flags_t __force)0x80000000U) +#define OBJFREELIST_SLAB(x) ((x)->flags & CFLGS_OBJFREELIST_SLAB) +#define OFF_SLAB(x) ((x)->flags & CFLGS_OFF_SLAB) + +#define BATCHREFILL_LIMIT 16 +/* + * Optimization question: fewer reaps means less probability for unnessary + * cpucache drain/refill cycles. + * + * OTOH the cpuarrays can contain lots of objects, + * which could lock up otherwise freeable slabs. + */ +#define REAPTIMEOUT_AC (2*HZ) +#define REAPTIMEOUT_NODE (4*HZ) + +#if STATS +#define STATS_INC_ACTIVE(x) ((x)->num_active++) +#define STATS_DEC_ACTIVE(x) ((x)->num_active--) +#define STATS_INC_ALLOCED(x) ((x)->num_allocations++) +#define STATS_INC_GROWN(x) ((x)->grown++) +#define STATS_ADD_REAPED(x,y) ((x)->reaped += (y)) +#define STATS_SET_HIGH(x) \ + do { \ + if ((x)->num_active > (x)->high_mark) \ + (x)->high_mark = (x)->num_active; \ + } while (0) +#define STATS_INC_ERR(x) ((x)->errors++) +#define STATS_INC_NODEALLOCS(x) ((x)->node_allocs++) +#define STATS_INC_NODEFREES(x) ((x)->node_frees++) +#define STATS_INC_ACOVERFLOW(x) ((x)->node_overflow++) +#define STATS_SET_FREEABLE(x, i) \ + do { \ + if ((x)->max_freeable < i) \ + (x)->max_freeable = i; \ + } while (0) +#define STATS_INC_ALLOCHIT(x) atomic_inc(&(x)->allochit) +#define STATS_INC_ALLOCMISS(x) atomic_inc(&(x)->allocmiss) +#define STATS_INC_FREEHIT(x) atomic_inc(&(x)->freehit) +#define STATS_INC_FREEMISS(x) atomic_inc(&(x)->freemiss) +#else +#define STATS_INC_ACTIVE(x) do { } while (0) +#define STATS_DEC_ACTIVE(x) do { } while (0) +#define STATS_INC_ALLOCED(x) do { } while (0) +#define STATS_INC_GROWN(x) do { } while (0) +#define STATS_ADD_REAPED(x,y) do { (void)(y); } while (0) +#define STATS_SET_HIGH(x) do { } while (0) +#define STATS_INC_ERR(x) do { } while (0) +#define STATS_INC_NODEALLOCS(x) do { } while (0) +#define STATS_INC_NODEFREES(x) do { } while (0) +#define STATS_INC_ACOVERFLOW(x) do { } while (0) +#define STATS_SET_FREEABLE(x, i) do { } while (0) +#define STATS_INC_ALLOCHIT(x) do { } while (0) +#define STATS_INC_ALLOCMISS(x) do { } while (0) +#define STATS_INC_FREEHIT(x) do { } while (0) +#define STATS_INC_FREEMISS(x) do { } while (0) +#endif + +#if DEBUG + +/* + * memory layout of objects: + * 0 : objp + * 0 .. cachep->obj_offset - BYTES_PER_WORD - 1: padding. This ensures that + * the end of an object is aligned with the end of the real + * allocation. Catches writes behind the end of the allocation. + * cachep->obj_offset - BYTES_PER_WORD .. cachep->obj_offset - 1: + * redzone word. + * cachep->obj_offset: The real object. + * cachep->size - 2* BYTES_PER_WORD: redzone word [BYTES_PER_WORD long] + * cachep->size - 1* BYTES_PER_WORD: last caller address + * [BYTES_PER_WORD long] + */ +static int obj_offset(struct kmem_cache *cachep) +{ + return cachep->obj_offset; +} + +static unsigned long long *dbg_redzone1(struct kmem_cache *cachep, void *objp) +{ + BUG_ON(!(cachep->flags & SLAB_RED_ZONE)); + return (unsigned long long*) (objp + obj_offset(cachep) - + sizeof(unsigned long long)); +} + +static unsigned long long *dbg_redzone2(struct kmem_cache *cachep, void *objp) +{ + BUG_ON(!(cachep->flags & SLAB_RED_ZONE)); + if (cachep->flags & SLAB_STORE_USER) + return (unsigned long long *)(objp + cachep->size - + sizeof(unsigned long long) - + REDZONE_ALIGN); + return (unsigned long long *) (objp + cachep->size - + sizeof(unsigned long long)); +} + +static void **dbg_userword(struct kmem_cache *cachep, void *objp) +{ + BUG_ON(!(cachep->flags & SLAB_STORE_USER)); + return (void **)(objp + cachep->size - BYTES_PER_WORD); +} + +#else + +#define obj_offset(x) 0 +#define dbg_redzone1(cachep, objp) ({BUG(); (unsigned long long *)NULL;}) +#define dbg_redzone2(cachep, objp) ({BUG(); (unsigned long long *)NULL;}) +#define dbg_userword(cachep, objp) ({BUG(); (void **)NULL;}) + +#endif + +/* + * Do not go above this order unless 0 objects fit into the slab or + * overridden on the command line. + */ +#define SLAB_MAX_ORDER_HI 1 +#define SLAB_MAX_ORDER_LO 0 +static int slab_max_order = SLAB_MAX_ORDER_LO; +static bool slab_max_order_set __initdata; + +static inline void *index_to_obj(struct kmem_cache *cache, struct page *page, + unsigned int idx) +{ + return page->s_mem + cache->size * idx; +} + +#define BOOT_CPUCACHE_ENTRIES 1 +/* internal cache of cache description objs */ +static struct kmem_cache kmem_cache_boot = { + .batchcount = 1, + .limit = BOOT_CPUCACHE_ENTRIES, + .shared = 1, + .size = sizeof(struct kmem_cache), + .name = "kmem_cache", +}; + +static DEFINE_PER_CPU(struct delayed_work, slab_reap_work); + +static inline struct array_cache *cpu_cache_get(struct kmem_cache *cachep) +{ + return this_cpu_ptr(cachep->cpu_cache); +} + +/* + * Calculate the number of objects and left-over bytes for a given buffer size. + */ +static unsigned int cache_estimate(unsigned long gfporder, size_t buffer_size, + slab_flags_t flags, size_t *left_over) +{ + unsigned int num; + size_t slab_size = PAGE_SIZE << gfporder; + + /* + * The slab management structure can be either off the slab or + * on it. For the latter case, the memory allocated for a + * slab is used for: + * + * - @buffer_size bytes for each object + * - One freelist_idx_t for each object + * + * We don't need to consider alignment of freelist because + * freelist will be at the end of slab page. The objects will be + * at the correct alignment. + * + * If the slab management structure is off the slab, then the + * alignment will already be calculated into the size. Because + * the slabs are all pages aligned, the objects will be at the + * correct alignment when allocated. + */ + if (flags & (CFLGS_OBJFREELIST_SLAB | CFLGS_OFF_SLAB)) { + num = slab_size / buffer_size; + *left_over = slab_size % buffer_size; + } else { + num = slab_size / (buffer_size + sizeof(freelist_idx_t)); + *left_over = slab_size % + (buffer_size + sizeof(freelist_idx_t)); + } + + return num; +} + +#if DEBUG +#define slab_error(cachep, msg) __slab_error(__func__, cachep, msg) + +static void __slab_error(const char *function, struct kmem_cache *cachep, + char *msg) +{ + pr_err("slab error in %s(): cache `%s': %s\n", + function, cachep->name, msg); + dump_stack(); + add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE); +} +#endif + +/* + * By default on NUMA we use alien caches to stage the freeing of + * objects allocated from other nodes. This causes massive memory + * inefficiencies when using fake NUMA setup to split memory into a + * large number of small nodes, so it can be disabled on the command + * line + */ + +static int use_alien_caches __read_mostly = 1; +static int __init noaliencache_setup(char *s) +{ + use_alien_caches = 0; + return 1; +} +__setup("noaliencache", noaliencache_setup); + +static int __init slab_max_order_setup(char *str) +{ + get_option(&str, &slab_max_order); + slab_max_order = slab_max_order < 0 ? 0 : + min(slab_max_order, MAX_ORDER - 1); + slab_max_order_set = true; + + return 1; +} +__setup("slab_max_order=", slab_max_order_setup); + +#ifdef CONFIG_NUMA +/* + * Special reaping functions for NUMA systems called from cache_reap(). + * These take care of doing round robin flushing of alien caches (containing + * objects freed on different nodes from which they were allocated) and the + * flushing of remote pcps by calling drain_node_pages. + */ +static DEFINE_PER_CPU(unsigned long, slab_reap_node); + +static void init_reap_node(int cpu) +{ + per_cpu(slab_reap_node, cpu) = next_node_in(cpu_to_mem(cpu), + node_online_map); +} + +static void next_reap_node(void) +{ + int node = __this_cpu_read(slab_reap_node); + + node = next_node_in(node, node_online_map); + __this_cpu_write(slab_reap_node, node); +} + +#else +#define init_reap_node(cpu) do { } while (0) +#define next_reap_node(void) do { } while (0) +#endif + +/* + * Initiate the reap timer running on the target CPU. We run at around 1 to 2Hz + * via the workqueue/eventd. + * Add the CPU number into the expiration time to minimize the possibility of + * the CPUs getting into lockstep and contending for the global cache chain + * lock. + */ +static void start_cpu_timer(int cpu) +{ + struct delayed_work *reap_work = &per_cpu(slab_reap_work, cpu); + + if (reap_work->work.func == NULL) { + init_reap_node(cpu); + INIT_DEFERRABLE_WORK(reap_work, cache_reap); + schedule_delayed_work_on(cpu, reap_work, + __round_jiffies_relative(HZ, cpu)); + } +} + +static void init_arraycache(struct array_cache *ac, int limit, int batch) +{ + if (ac) { + ac->avail = 0; + ac->limit = limit; + ac->batchcount = batch; + ac->touched = 0; + } +} + +static struct array_cache *alloc_arraycache(int node, int entries, + int batchcount, gfp_t gfp) +{ + size_t memsize = sizeof(void *) * entries + sizeof(struct array_cache); + struct array_cache *ac = NULL; + + ac = kmalloc_node(memsize, gfp, node); + /* + * The array_cache structures contain pointers to free object. + * However, when such objects are allocated or transferred to another + * cache the pointers are not cleared and they could be counted as + * valid references during a kmemleak scan. Therefore, kmemleak must + * not scan such objects. + */ + kmemleak_no_scan(ac); + init_arraycache(ac, entries, batchcount); + return ac; +} + +static noinline void cache_free_pfmemalloc(struct kmem_cache *cachep, + struct page *page, void *objp) +{ + struct kmem_cache_node *n; + int page_node; + LIST_HEAD(list); + + page_node = page_to_nid(page); + n = get_node(cachep, page_node); + + spin_lock(&n->list_lock); + free_block(cachep, &objp, 1, page_node, &list); + spin_unlock(&n->list_lock); + + slabs_destroy(cachep, &list); +} + +/* + * Transfer objects in one arraycache to another. + * Locking must be handled by the caller. + * + * Return the number of entries transferred. + */ +static int transfer_objects(struct array_cache *to, + struct array_cache *from, unsigned int max) +{ + /* Figure out how many entries to transfer */ + int nr = min3(from->avail, max, to->limit - to->avail); + + if (!nr) + return 0; + + memcpy(to->entry + to->avail, from->entry + from->avail -nr, + sizeof(void *) *nr); + + from->avail -= nr; + to->avail += nr; + return nr; +} + +/* &alien->lock must be held by alien callers. */ +static __always_inline void __free_one(struct array_cache *ac, void *objp) +{ + /* Avoid trivial double-free. */ + if (IS_ENABLED(CONFIG_SLAB_FREELIST_HARDENED) && + WARN_ON_ONCE(ac->avail > 0 && ac->entry[ac->avail - 1] == objp)) + return; + ac->entry[ac->avail++] = objp; +} + +#ifndef CONFIG_NUMA + +#define drain_alien_cache(cachep, alien) do { } while (0) +#define reap_alien(cachep, n) do { } while (0) + +static inline struct alien_cache **alloc_alien_cache(int node, + int limit, gfp_t gfp) +{ + return NULL; +} + +static inline void free_alien_cache(struct alien_cache **ac_ptr) +{ +} + +static inline int cache_free_alien(struct kmem_cache *cachep, void *objp) +{ + return 0; +} + +static inline void *alternate_node_alloc(struct kmem_cache *cachep, + gfp_t flags) +{ + return NULL; +} + +static inline void *____cache_alloc_node(struct kmem_cache *cachep, + gfp_t flags, int nodeid) +{ + return NULL; +} + +static inline gfp_t gfp_exact_node(gfp_t flags) +{ + return flags & ~__GFP_NOFAIL; +} + +#else /* CONFIG_NUMA */ + +static void *____cache_alloc_node(struct kmem_cache *, gfp_t, int); +static void *alternate_node_alloc(struct kmem_cache *, gfp_t); + +static struct alien_cache *__alloc_alien_cache(int node, int entries, + int batch, gfp_t gfp) +{ + size_t memsize = sizeof(void *) * entries + sizeof(struct alien_cache); + struct alien_cache *alc = NULL; + + alc = kmalloc_node(memsize, gfp, node); + if (alc) { + kmemleak_no_scan(alc); + init_arraycache(&alc->ac, entries, batch); + spin_lock_init(&alc->lock); + } + return alc; +} + +static struct alien_cache **alloc_alien_cache(int node, int limit, gfp_t gfp) +{ + struct alien_cache **alc_ptr; + int i; + + if (limit > 1) + limit = 12; + alc_ptr = kcalloc_node(nr_node_ids, sizeof(void *), gfp, node); + if (!alc_ptr) + return NULL; + + for_each_node(i) { + if (i == node || !node_online(i)) + continue; + alc_ptr[i] = __alloc_alien_cache(node, limit, 0xbaadf00d, gfp); + if (!alc_ptr[i]) { + for (i--; i >= 0; i--) + kfree(alc_ptr[i]); + kfree(alc_ptr); + return NULL; + } + } + return alc_ptr; +} + +static void free_alien_cache(struct alien_cache **alc_ptr) +{ + int i; + + if (!alc_ptr) + return; + for_each_node(i) + kfree(alc_ptr[i]); + kfree(alc_ptr); +} + +static void __drain_alien_cache(struct kmem_cache *cachep, + struct array_cache *ac, int node, + struct list_head *list) +{ + struct kmem_cache_node *n = get_node(cachep, node); + + if (ac->avail) { + spin_lock(&n->list_lock); + /* + * Stuff objects into the remote nodes shared array first. + * That way we could avoid the overhead of putting the objects + * into the free lists and getting them back later. + */ + if (n->shared) + transfer_objects(n->shared, ac, ac->limit); + + free_block(cachep, ac->entry, ac->avail, node, list); + ac->avail = 0; + spin_unlock(&n->list_lock); + } +} + +/* + * Called from cache_reap() to regularly drain alien caches round robin. + */ +static void reap_alien(struct kmem_cache *cachep, struct kmem_cache_node *n) +{ + int node = __this_cpu_read(slab_reap_node); + + if (n->alien) { + struct alien_cache *alc = n->alien[node]; + struct array_cache *ac; + + if (alc) { + ac = &alc->ac; + if (ac->avail && spin_trylock_irq(&alc->lock)) { + LIST_HEAD(list); + + __drain_alien_cache(cachep, ac, node, &list); + spin_unlock_irq(&alc->lock); + slabs_destroy(cachep, &list); + } + } + } +} + +static void drain_alien_cache(struct kmem_cache *cachep, + struct alien_cache **alien) +{ + int i = 0; + struct alien_cache *alc; + struct array_cache *ac; + unsigned long flags; + + for_each_online_node(i) { + alc = alien[i]; + if (alc) { + LIST_HEAD(list); + + ac = &alc->ac; + spin_lock_irqsave(&alc->lock, flags); + __drain_alien_cache(cachep, ac, i, &list); + spin_unlock_irqrestore(&alc->lock, flags); + slabs_destroy(cachep, &list); + } + } +} + +static int __cache_free_alien(struct kmem_cache *cachep, void *objp, + int node, int page_node) +{ + struct kmem_cache_node *n; + struct alien_cache *alien = NULL; + struct array_cache *ac; + LIST_HEAD(list); + + n = get_node(cachep, node); + STATS_INC_NODEFREES(cachep); + if (n->alien && n->alien[page_node]) { + alien = n->alien[page_node]; + ac = &alien->ac; + spin_lock(&alien->lock); + if (unlikely(ac->avail == ac->limit)) { + STATS_INC_ACOVERFLOW(cachep); + __drain_alien_cache(cachep, ac, page_node, &list); + } + __free_one(ac, objp); + spin_unlock(&alien->lock); + slabs_destroy(cachep, &list); + } else { + n = get_node(cachep, page_node); + spin_lock(&n->list_lock); + free_block(cachep, &objp, 1, page_node, &list); + spin_unlock(&n->list_lock); + slabs_destroy(cachep, &list); + } + return 1; +} + +static inline int cache_free_alien(struct kmem_cache *cachep, void *objp) +{ + int page_node = page_to_nid(virt_to_page(objp)); + int node = numa_mem_id(); + /* + * Make sure we are not freeing a object from another node to the array + * cache on this cpu. + */ + if (likely(node == page_node)) + return 0; + + return __cache_free_alien(cachep, objp, node, page_node); +} + +/* + * Construct gfp mask to allocate from a specific node but do not reclaim or + * warn about failures. + */ +static inline gfp_t gfp_exact_node(gfp_t flags) +{ + return (flags | __GFP_THISNODE | __GFP_NOWARN) & ~(__GFP_RECLAIM|__GFP_NOFAIL); +} +#endif + +static int init_cache_node(struct kmem_cache *cachep, int node, gfp_t gfp) +{ + struct kmem_cache_node *n; + + /* + * Set up the kmem_cache_node for cpu before we can + * begin anything. Make sure some other cpu on this + * node has not already allocated this + */ + n = get_node(cachep, node); + if (n) { + spin_lock_irq(&n->list_lock); + n->free_limit = (1 + nr_cpus_node(node)) * cachep->batchcount + + cachep->num; + spin_unlock_irq(&n->list_lock); + + return 0; + } + + n = kmalloc_node(sizeof(struct kmem_cache_node), gfp, node); + if (!n) + return -ENOMEM; + + kmem_cache_node_init(n); + n->next_reap = jiffies + REAPTIMEOUT_NODE + + ((unsigned long)cachep) % REAPTIMEOUT_NODE; + + n->free_limit = + (1 + nr_cpus_node(node)) * cachep->batchcount + cachep->num; + + /* + * The kmem_cache_nodes don't come and go as CPUs + * come and go. slab_mutex is sufficient + * protection here. + */ + cachep->node[node] = n; + + return 0; +} + +#if (defined(CONFIG_NUMA) && defined(CONFIG_MEMORY_HOTPLUG)) || defined(CONFIG_SMP) +/* + * Allocates and initializes node for a node on each slab cache, used for + * either memory or cpu hotplug. If memory is being hot-added, the kmem_cache_node + * will be allocated off-node since memory is not yet online for the new node. + * When hotplugging memory or a cpu, existing node are not replaced if + * already in use. + * + * Must hold slab_mutex. + */ +static int init_cache_node_node(int node) +{ + int ret; + struct kmem_cache *cachep; + + list_for_each_entry(cachep, &slab_caches, list) { + ret = init_cache_node(cachep, node, GFP_KERNEL); + if (ret) + return ret; + } + + return 0; +} +#endif + +static int setup_kmem_cache_node(struct kmem_cache *cachep, + int node, gfp_t gfp, bool force_change) +{ + int ret = -ENOMEM; + struct kmem_cache_node *n; + struct array_cache *old_shared = NULL; + struct array_cache *new_shared = NULL; + struct alien_cache **new_alien = NULL; + LIST_HEAD(list); + + if (use_alien_caches) { + new_alien = alloc_alien_cache(node, cachep->limit, gfp); + if (!new_alien) + goto fail; + } + + if (cachep->shared) { + new_shared = alloc_arraycache(node, + cachep->shared * cachep->batchcount, 0xbaadf00d, gfp); + if (!new_shared) + goto fail; + } + + ret = init_cache_node(cachep, node, gfp); + if (ret) + goto fail; + + n = get_node(cachep, node); + spin_lock_irq(&n->list_lock); + if (n->shared && force_change) { + free_block(cachep, n->shared->entry, + n->shared->avail, node, &list); + n->shared->avail = 0; + } + + if (!n->shared || force_change) { + old_shared = n->shared; + n->shared = new_shared; + new_shared = NULL; + } + + if (!n->alien) { + n->alien = new_alien; + new_alien = NULL; + } + + spin_unlock_irq(&n->list_lock); + slabs_destroy(cachep, &list); + + /* + * To protect lockless access to n->shared during irq disabled context. + * If n->shared isn't NULL in irq disabled context, accessing to it is + * guaranteed to be valid until irq is re-enabled, because it will be + * freed after synchronize_rcu(). + */ + if (old_shared && force_change) + synchronize_rcu(); + +fail: + kfree(old_shared); + kfree(new_shared); + free_alien_cache(new_alien); + + return ret; +} + +#ifdef CONFIG_SMP + +static void cpuup_canceled(long cpu) +{ + struct kmem_cache *cachep; + struct kmem_cache_node *n = NULL; + int node = cpu_to_mem(cpu); + const struct cpumask *mask = cpumask_of_node(node); + + list_for_each_entry(cachep, &slab_caches, list) { + struct array_cache *nc; + struct array_cache *shared; + struct alien_cache **alien; + LIST_HEAD(list); + + n = get_node(cachep, node); + if (!n) + continue; + + spin_lock_irq(&n->list_lock); + + /* Free limit for this kmem_cache_node */ + n->free_limit -= cachep->batchcount; + + /* cpu is dead; no one can alloc from it. */ + nc = per_cpu_ptr(cachep->cpu_cache, cpu); + free_block(cachep, nc->entry, nc->avail, node, &list); + nc->avail = 0; + + if (!cpumask_empty(mask)) { + spin_unlock_irq(&n->list_lock); + goto free_slab; + } + + shared = n->shared; + if (shared) { + free_block(cachep, shared->entry, + shared->avail, node, &list); + n->shared = NULL; + } + + alien = n->alien; + n->alien = NULL; + + spin_unlock_irq(&n->list_lock); + + kfree(shared); + if (alien) { + drain_alien_cache(cachep, alien); + free_alien_cache(alien); + } + +free_slab: + slabs_destroy(cachep, &list); + } + /* + * In the previous loop, all the objects were freed to + * the respective cache's slabs, now we can go ahead and + * shrink each nodelist to its limit. + */ + list_for_each_entry(cachep, &slab_caches, list) { + n = get_node(cachep, node); + if (!n) + continue; + drain_freelist(cachep, n, INT_MAX); + } +} + +static int cpuup_prepare(long cpu) +{ + struct kmem_cache *cachep; + int node = cpu_to_mem(cpu); + int err; + + /* + * We need to do this right in the beginning since + * alloc_arraycache's are going to use this list. + * kmalloc_node allows us to add the slab to the right + * kmem_cache_node and not this cpu's kmem_cache_node + */ + err = init_cache_node_node(node); + if (err < 0) + goto bad; + + /* + * Now we can go ahead with allocating the shared arrays and + * array caches + */ + list_for_each_entry(cachep, &slab_caches, list) { + err = setup_kmem_cache_node(cachep, node, GFP_KERNEL, false); + if (err) + goto bad; + } + + return 0; +bad: + cpuup_canceled(cpu); + return -ENOMEM; +} + +int slab_prepare_cpu(unsigned int cpu) +{ + int err; + + mutex_lock(&slab_mutex); + err = cpuup_prepare(cpu); + mutex_unlock(&slab_mutex); + return err; +} + +/* + * This is called for a failed online attempt and for a successful + * offline. + * + * Even if all the cpus of a node are down, we don't free the + * kmem_cache_node of any cache. This to avoid a race between cpu_down, and + * a kmalloc allocation from another cpu for memory from the node of + * the cpu going down. The kmem_cache_node structure is usually allocated from + * kmem_cache_create() and gets destroyed at kmem_cache_destroy(). + */ +int slab_dead_cpu(unsigned int cpu) +{ + mutex_lock(&slab_mutex); + cpuup_canceled(cpu); + mutex_unlock(&slab_mutex); + return 0; +} +#endif + +static int slab_online_cpu(unsigned int cpu) +{ + start_cpu_timer(cpu); + return 0; +} + +static int slab_offline_cpu(unsigned int cpu) +{ + /* + * Shutdown cache reaper. Note that the slab_mutex is held so + * that if cache_reap() is invoked it cannot do anything + * expensive but will only modify reap_work and reschedule the + * timer. + */ + cancel_delayed_work_sync(&per_cpu(slab_reap_work, cpu)); + /* Now the cache_reaper is guaranteed to be not running. */ + per_cpu(slab_reap_work, cpu).work.func = NULL; + return 0; +} + +#if defined(CONFIG_NUMA) && defined(CONFIG_MEMORY_HOTPLUG) +/* + * Drains freelist for a node on each slab cache, used for memory hot-remove. + * Returns -EBUSY if all objects cannot be drained so that the node is not + * removed. + * + * Must hold slab_mutex. + */ +static int __meminit drain_cache_node_node(int node) +{ + struct kmem_cache *cachep; + int ret = 0; + + list_for_each_entry(cachep, &slab_caches, list) { + struct kmem_cache_node *n; + + n = get_node(cachep, node); + if (!n) + continue; + + drain_freelist(cachep, n, INT_MAX); + + if (!list_empty(&n->slabs_full) || + !list_empty(&n->slabs_partial)) { + ret = -EBUSY; + break; + } + } + return ret; +} + +static int __meminit slab_memory_callback(struct notifier_block *self, + unsigned long action, void *arg) +{ + struct memory_notify *mnb = arg; + int ret = 0; + int nid; + + nid = mnb->status_change_nid; + if (nid < 0) + goto out; + + switch (action) { + case MEM_GOING_ONLINE: + mutex_lock(&slab_mutex); + ret = init_cache_node_node(nid); + mutex_unlock(&slab_mutex); + break; + case MEM_GOING_OFFLINE: + mutex_lock(&slab_mutex); + ret = drain_cache_node_node(nid); + mutex_unlock(&slab_mutex); + break; + case MEM_ONLINE: + case MEM_OFFLINE: + case MEM_CANCEL_ONLINE: + case MEM_CANCEL_OFFLINE: + break; + } +out: + return notifier_from_errno(ret); +} +#endif /* CONFIG_NUMA && CONFIG_MEMORY_HOTPLUG */ + +/* + * swap the static kmem_cache_node with kmalloced memory + */ +static void __init init_list(struct kmem_cache *cachep, struct kmem_cache_node *list, + int nodeid) +{ + struct kmem_cache_node *ptr; + + ptr = kmalloc_node(sizeof(struct kmem_cache_node), GFP_NOWAIT, nodeid); + BUG_ON(!ptr); + + memcpy(ptr, list, sizeof(struct kmem_cache_node)); + /* + * Do not assume that spinlocks can be initialized via memcpy: + */ + spin_lock_init(&ptr->list_lock); + + MAKE_ALL_LISTS(cachep, ptr, nodeid); + cachep->node[nodeid] = ptr; +} + +/* + * For setting up all the kmem_cache_node for cache whose buffer_size is same as + * size of kmem_cache_node. + */ +static void __init set_up_node(struct kmem_cache *cachep, int index) +{ + int node; + + for_each_online_node(node) { + cachep->node[node] = &init_kmem_cache_node[index + node]; + cachep->node[node]->next_reap = jiffies + + REAPTIMEOUT_NODE + + ((unsigned long)cachep) % REAPTIMEOUT_NODE; + } +} + +/* + * Initialisation. Called after the page allocator have been initialised and + * before smp_init(). + */ +void __init kmem_cache_init(void) +{ + int i; + + kmem_cache = &kmem_cache_boot; + + if (!IS_ENABLED(CONFIG_NUMA) || num_possible_nodes() == 1) + use_alien_caches = 0; + + for (i = 0; i < NUM_INIT_LISTS; i++) + kmem_cache_node_init(&init_kmem_cache_node[i]); + + /* + * Fragmentation resistance on low memory - only use bigger + * page orders on machines with more than 32MB of memory if + * not overridden on the command line. + */ + if (!slab_max_order_set && totalram_pages() > (32 << 20) >> PAGE_SHIFT) + slab_max_order = SLAB_MAX_ORDER_HI; + + /* Bootstrap is tricky, because several objects are allocated + * from caches that do not exist yet: + * 1) initialize the kmem_cache cache: it contains the struct + * kmem_cache structures of all caches, except kmem_cache itself: + * kmem_cache is statically allocated. + * Initially an __init data area is used for the head array and the + * kmem_cache_node structures, it's replaced with a kmalloc allocated + * array at the end of the bootstrap. + * 2) Create the first kmalloc cache. + * The struct kmem_cache for the new cache is allocated normally. + * An __init data area is used for the head array. + * 3) Create the remaining kmalloc caches, with minimally sized + * head arrays. + * 4) Replace the __init data head arrays for kmem_cache and the first + * kmalloc cache with kmalloc allocated arrays. + * 5) Replace the __init data for kmem_cache_node for kmem_cache and + * the other cache's with kmalloc allocated memory. + * 6) Resize the head arrays of the kmalloc caches to their final sizes. + */ + + /* 1) create the kmem_cache */ + + /* + * struct kmem_cache size depends on nr_node_ids & nr_cpu_ids + */ + create_boot_cache(kmem_cache, "kmem_cache", + offsetof(struct kmem_cache, node) + + nr_node_ids * sizeof(struct kmem_cache_node *), + SLAB_HWCACHE_ALIGN, 0, 0); + list_add(&kmem_cache->list, &slab_caches); + slab_state = PARTIAL; + + /* + * Initialize the caches that provide memory for the kmem_cache_node + * structures first. Without this, further allocations will bug. + */ + kmalloc_caches[KMALLOC_NORMAL][INDEX_NODE] = create_kmalloc_cache( + kmalloc_info[INDEX_NODE].name[KMALLOC_NORMAL], + kmalloc_info[INDEX_NODE].size, + ARCH_KMALLOC_FLAGS, 0, + kmalloc_info[INDEX_NODE].size); + slab_state = PARTIAL_NODE; + setup_kmalloc_cache_index_table(); + + slab_early_init = 0; + + /* 5) Replace the bootstrap kmem_cache_node */ + { + int nid; + + for_each_online_node(nid) { + init_list(kmem_cache, &init_kmem_cache_node[CACHE_CACHE + nid], nid); + + init_list(kmalloc_caches[KMALLOC_NORMAL][INDEX_NODE], + &init_kmem_cache_node[SIZE_NODE + nid], nid); + } + } + + create_kmalloc_caches(ARCH_KMALLOC_FLAGS); +} + +void __init kmem_cache_init_late(void) +{ + struct kmem_cache *cachep; + + /* 6) resize the head arrays to their final sizes */ + mutex_lock(&slab_mutex); + list_for_each_entry(cachep, &slab_caches, list) + if (enable_cpucache(cachep, GFP_NOWAIT)) + BUG(); + mutex_unlock(&slab_mutex); + + /* Done! */ + slab_state = FULL; + +#ifdef CONFIG_NUMA + /* + * Register a memory hotplug callback that initializes and frees + * node. + */ + hotplug_memory_notifier(slab_memory_callback, SLAB_CALLBACK_PRI); +#endif + + /* + * The reap timers are started later, with a module init call: That part + * of the kernel is not yet operational. + */ +} + +static int __init cpucache_init(void) +{ + int ret; + + /* + * Register the timers that return unneeded pages to the page allocator + */ + ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "SLAB online", + slab_online_cpu, slab_offline_cpu); + WARN_ON(ret < 0); + + return 0; +} +__initcall(cpucache_init); + +static noinline void +slab_out_of_memory(struct kmem_cache *cachep, gfp_t gfpflags, int nodeid) +{ +#if DEBUG + struct kmem_cache_node *n; + unsigned long flags; + int node; + static DEFINE_RATELIMIT_STATE(slab_oom_rs, DEFAULT_RATELIMIT_INTERVAL, + DEFAULT_RATELIMIT_BURST); + + if ((gfpflags & __GFP_NOWARN) || !__ratelimit(&slab_oom_rs)) + return; + + pr_warn("SLAB: Unable to allocate memory on node %d, gfp=%#x(%pGg)\n", + nodeid, gfpflags, &gfpflags); + pr_warn(" cache: %s, object size: %d, order: %d\n", + cachep->name, cachep->size, cachep->gfporder); + + for_each_kmem_cache_node(cachep, node, n) { + unsigned long total_slabs, free_slabs, free_objs; + + spin_lock_irqsave(&n->list_lock, flags); + total_slabs = n->total_slabs; + free_slabs = n->free_slabs; + free_objs = n->free_objects; + spin_unlock_irqrestore(&n->list_lock, flags); + + pr_warn(" node %d: slabs: %ld/%ld, objs: %ld/%ld\n", + node, total_slabs - free_slabs, total_slabs, + (total_slabs * cachep->num) - free_objs, + total_slabs * cachep->num); + } +#endif +} + +/* + * Interface to system's page allocator. No need to hold the + * kmem_cache_node ->list_lock. + * + * If we requested dmaable memory, we will get it. Even if we + * did not request dmaable memory, we might get it, but that + * would be relatively rare and ignorable. + */ +static struct page *kmem_getpages(struct kmem_cache *cachep, gfp_t flags, + int nodeid) +{ + struct page *page; + + flags |= cachep->allocflags; + + page = __alloc_pages_node(nodeid, flags, cachep->gfporder); + if (!page) { + slab_out_of_memory(cachep, flags, nodeid); + return NULL; + } + + account_slab_page(page, cachep->gfporder, cachep); + __SetPageSlab(page); + /* Record if ALLOC_NO_WATERMARKS was set when allocating the slab */ + if (sk_memalloc_socks() && page_is_pfmemalloc(page)) + SetPageSlabPfmemalloc(page); + + return page; +} + +/* + * Interface to system's page release. + */ +static void kmem_freepages(struct kmem_cache *cachep, struct page *page) +{ + int order = cachep->gfporder; + + BUG_ON(!PageSlab(page)); + __ClearPageSlabPfmemalloc(page); + __ClearPageSlab(page); + page_mapcount_reset(page); + page->mapping = NULL; + + if (current->reclaim_state) + current->reclaim_state->reclaimed_slab += 1 << order; + unaccount_slab_page(page, order, cachep); + __free_pages(page, order); +} + +static void kmem_rcu_free(struct rcu_head *head) +{ + struct kmem_cache *cachep; + struct page *page; + + page = container_of(head, struct page, rcu_head); + cachep = page->slab_cache; + + kmem_freepages(cachep, page); +} + +#if DEBUG +static bool is_debug_pagealloc_cache(struct kmem_cache *cachep) +{ + if (debug_pagealloc_enabled_static() && OFF_SLAB(cachep) && + (cachep->size % PAGE_SIZE) == 0) + return true; + + return false; +} + +#ifdef CONFIG_DEBUG_PAGEALLOC +static void slab_kernel_map(struct kmem_cache *cachep, void *objp, int map) +{ + if (!is_debug_pagealloc_cache(cachep)) + return; + + kernel_map_pages(virt_to_page(objp), cachep->size / PAGE_SIZE, map); +} + +#else +static inline void slab_kernel_map(struct kmem_cache *cachep, void *objp, + int map) {} + +#endif + +static void poison_obj(struct kmem_cache *cachep, void *addr, unsigned char val) +{ + int size = cachep->object_size; + addr = &((char *)addr)[obj_offset(cachep)]; + + memset(addr, val, size); + *(unsigned char *)(addr + size - 1) = POISON_END; +} + +static void dump_line(char *data, int offset, int limit) +{ + int i; + unsigned char error = 0; + int bad_count = 0; + + pr_err("%03x: ", offset); + for (i = 0; i < limit; i++) { + if (data[offset + i] != POISON_FREE) { + error = data[offset + i]; + bad_count++; + } + } + print_hex_dump(KERN_CONT, "", 0, 16, 1, + &data[offset], limit, 1); + + if (bad_count == 1) { + error ^= POISON_FREE; + if (!(error & (error - 1))) { + pr_err("Single bit error detected. Probably bad RAM.\n"); +#ifdef CONFIG_X86 + pr_err("Run memtest86+ or a similar memory test tool.\n"); +#else + pr_err("Run a memory test tool.\n"); +#endif + } + } +} +#endif + +#if DEBUG + +static void print_objinfo(struct kmem_cache *cachep, void *objp, int lines) +{ + int i, size; + char *realobj; + + if (cachep->flags & SLAB_RED_ZONE) { + pr_err("Redzone: 0x%llx/0x%llx\n", + *dbg_redzone1(cachep, objp), + *dbg_redzone2(cachep, objp)); + } + + if (cachep->flags & SLAB_STORE_USER) + pr_err("Last user: (%pSR)\n", *dbg_userword(cachep, objp)); + realobj = (char *)objp + obj_offset(cachep); + size = cachep->object_size; + for (i = 0; i < size && lines; i += 16, lines--) { + int limit; + limit = 16; + if (i + limit > size) + limit = size - i; + dump_line(realobj, i, limit); + } +} + +static void check_poison_obj(struct kmem_cache *cachep, void *objp) +{ + char *realobj; + int size, i; + int lines = 0; + + if (is_debug_pagealloc_cache(cachep)) + return; + + realobj = (char *)objp + obj_offset(cachep); + size = cachep->object_size; + + for (i = 0; i < size; i++) { + char exp = POISON_FREE; + if (i == size - 1) + exp = POISON_END; + if (realobj[i] != exp) { + int limit; + /* Mismatch ! */ + /* Print header */ + if (lines == 0) { + pr_err("Slab corruption (%s): %s start=%px, len=%d\n", + print_tainted(), cachep->name, + realobj, size); + print_objinfo(cachep, objp, 0); + } + /* Hexdump the affected line */ + i = (i / 16) * 16; + limit = 16; + if (i + limit > size) + limit = size - i; + dump_line(realobj, i, limit); + i += 16; + lines++; + /* Limit to 5 lines */ + if (lines > 5) + break; + } + } + if (lines != 0) { + /* Print some data about the neighboring objects, if they + * exist: + */ + struct page *page = virt_to_head_page(objp); + unsigned int objnr; + + objnr = obj_to_index(cachep, page, objp); + if (objnr) { + objp = index_to_obj(cachep, page, objnr - 1); + realobj = (char *)objp + obj_offset(cachep); + pr_err("Prev obj: start=%px, len=%d\n", realobj, size); + print_objinfo(cachep, objp, 2); + } + if (objnr + 1 < cachep->num) { + objp = index_to_obj(cachep, page, objnr + 1); + realobj = (char *)objp + obj_offset(cachep); + pr_err("Next obj: start=%px, len=%d\n", realobj, size); + print_objinfo(cachep, objp, 2); + } + } +} +#endif + +#if DEBUG +static void slab_destroy_debugcheck(struct kmem_cache *cachep, + struct page *page) +{ + int i; + + if (OBJFREELIST_SLAB(cachep) && cachep->flags & SLAB_POISON) { + poison_obj(cachep, page->freelist - obj_offset(cachep), + POISON_FREE); + } + + for (i = 0; i < cachep->num; i++) { + void *objp = index_to_obj(cachep, page, i); + + if (cachep->flags & SLAB_POISON) { + check_poison_obj(cachep, objp); + slab_kernel_map(cachep, objp, 1); + } + if (cachep->flags & SLAB_RED_ZONE) { + if (*dbg_redzone1(cachep, objp) != RED_INACTIVE) + slab_error(cachep, "start of a freed object was overwritten"); + if (*dbg_redzone2(cachep, objp) != RED_INACTIVE) + slab_error(cachep, "end of a freed object was overwritten"); + } + } +} +#else +static void slab_destroy_debugcheck(struct kmem_cache *cachep, + struct page *page) +{ +} +#endif + +/** + * slab_destroy - destroy and release all objects in a slab + * @cachep: cache pointer being destroyed + * @page: page pointer being destroyed + * + * Destroy all the objs in a slab page, and release the mem back to the system. + * Before calling the slab page must have been unlinked from the cache. The + * kmem_cache_node ->list_lock is not held/needed. + */ +static void slab_destroy(struct kmem_cache *cachep, struct page *page) +{ + void *freelist; + + freelist = page->freelist; + slab_destroy_debugcheck(cachep, page); + if (unlikely(cachep->flags & SLAB_TYPESAFE_BY_RCU)) + call_rcu(&page->rcu_head, kmem_rcu_free); + else + kmem_freepages(cachep, page); + + /* + * From now on, we don't use freelist + * although actual page can be freed in rcu context + */ + if (OFF_SLAB(cachep)) + kmem_cache_free(cachep->freelist_cache, freelist); +} + +/* + * Update the size of the caches before calling slabs_destroy as it may + * recursively call kfree. + */ +static void slabs_destroy(struct kmem_cache *cachep, struct list_head *list) +{ + struct page *page, *n; + + list_for_each_entry_safe(page, n, list, slab_list) { + list_del(&page->slab_list); + slab_destroy(cachep, page); + } +} + +/** + * calculate_slab_order - calculate size (page order) of slabs + * @cachep: pointer to the cache that is being created + * @size: size of objects to be created in this cache. + * @flags: slab allocation flags + * + * Also calculates the number of objects per slab. + * + * This could be made much more intelligent. For now, try to avoid using + * high order pages for slabs. When the gfp() functions are more friendly + * towards high-order requests, this should be changed. + * + * Return: number of left-over bytes in a slab + */ +static size_t calculate_slab_order(struct kmem_cache *cachep, + size_t size, slab_flags_t flags) +{ + size_t left_over = 0; + int gfporder; + + for (gfporder = 0; gfporder <= KMALLOC_MAX_ORDER; gfporder++) { + unsigned int num; + size_t remainder; + + num = cache_estimate(gfporder, size, flags, &remainder); + if (!num) + continue; + + /* Can't handle number of objects more than SLAB_OBJ_MAX_NUM */ + if (num > SLAB_OBJ_MAX_NUM) + break; + + if (flags & CFLGS_OFF_SLAB) { + struct kmem_cache *freelist_cache; + size_t freelist_size; + + freelist_size = num * sizeof(freelist_idx_t); + freelist_cache = kmalloc_slab(freelist_size, 0u); + if (!freelist_cache) + continue; + + /* + * Needed to avoid possible looping condition + * in cache_grow_begin() + */ + if (OFF_SLAB(freelist_cache)) + continue; + + /* check if off slab has enough benefit */ + if (freelist_cache->size > cachep->size / 2) + continue; + } + + /* Found something acceptable - save it away */ + cachep->num = num; + cachep->gfporder = gfporder; + left_over = remainder; + + /* + * A VFS-reclaimable slab tends to have most allocations + * as GFP_NOFS and we really don't want to have to be allocating + * higher-order pages when we are unable to shrink dcache. + */ + if (flags & SLAB_RECLAIM_ACCOUNT) + break; + + /* + * Large number of objects is good, but very large slabs are + * currently bad for the gfp()s. + */ + if (gfporder >= slab_max_order) + break; + + /* + * Acceptable internal fragmentation? + */ + if (left_over * 8 <= (PAGE_SIZE << gfporder)) + break; + } + return left_over; +} + +static struct array_cache __percpu *alloc_kmem_cache_cpus( + struct kmem_cache *cachep, int entries, int batchcount) +{ + int cpu; + size_t size; + struct array_cache __percpu *cpu_cache; + + size = sizeof(void *) * entries + sizeof(struct array_cache); + cpu_cache = __alloc_percpu(size, sizeof(void *)); + + if (!cpu_cache) + return NULL; + + for_each_possible_cpu(cpu) { + init_arraycache(per_cpu_ptr(cpu_cache, cpu), + entries, batchcount); + } + + return cpu_cache; +} + +static int __ref setup_cpu_cache(struct kmem_cache *cachep, gfp_t gfp) +{ + if (slab_state >= FULL) + return enable_cpucache(cachep, gfp); + + cachep->cpu_cache = alloc_kmem_cache_cpus(cachep, 1, 1); + if (!cachep->cpu_cache) + return 1; + + if (slab_state == DOWN) { + /* Creation of first cache (kmem_cache). */ + set_up_node(kmem_cache, CACHE_CACHE); + } else if (slab_state == PARTIAL) { + /* For kmem_cache_node */ + set_up_node(cachep, SIZE_NODE); + } else { + int node; + + for_each_online_node(node) { + cachep->node[node] = kmalloc_node( + sizeof(struct kmem_cache_node), gfp, node); + BUG_ON(!cachep->node[node]); + kmem_cache_node_init(cachep->node[node]); + } + } + + cachep->node[numa_mem_id()]->next_reap = + jiffies + REAPTIMEOUT_NODE + + ((unsigned long)cachep) % REAPTIMEOUT_NODE; + + cpu_cache_get(cachep)->avail = 0; + cpu_cache_get(cachep)->limit = BOOT_CPUCACHE_ENTRIES; + cpu_cache_get(cachep)->batchcount = 1; + cpu_cache_get(cachep)->touched = 0; + cachep->batchcount = 1; + cachep->limit = BOOT_CPUCACHE_ENTRIES; + return 0; +} + +slab_flags_t kmem_cache_flags(unsigned int object_size, + slab_flags_t flags, const char *name) +{ + return flags; +} + +struct kmem_cache * +__kmem_cache_alias(const char *name, unsigned int size, unsigned int align, + slab_flags_t flags, void (*ctor)(void *)) +{ + struct kmem_cache *cachep; + + cachep = find_mergeable(size, align, flags, name, ctor); + if (cachep) { + cachep->refcount++; + + /* + * Adjust the object sizes so that we clear + * the complete object on kzalloc. + */ + cachep->object_size = max_t(int, cachep->object_size, size); + } + return cachep; +} + +static bool set_objfreelist_slab_cache(struct kmem_cache *cachep, + size_t size, slab_flags_t flags) +{ + size_t left; + + cachep->num = 0; + + /* + * If slab auto-initialization on free is enabled, store the freelist + * off-slab, so that its contents don't end up in one of the allocated + * objects. + */ + if (unlikely(slab_want_init_on_free(cachep))) + return false; + + if (cachep->ctor || flags & SLAB_TYPESAFE_BY_RCU) + return false; + + left = calculate_slab_order(cachep, size, + flags | CFLGS_OBJFREELIST_SLAB); + if (!cachep->num) + return false; + + if (cachep->num * sizeof(freelist_idx_t) > cachep->object_size) + return false; + + cachep->colour = left / cachep->colour_off; + + return true; +} + +static bool set_off_slab_cache(struct kmem_cache *cachep, + size_t size, slab_flags_t flags) +{ + size_t left; + + cachep->num = 0; + + /* + * Always use on-slab management when SLAB_NOLEAKTRACE + * to avoid recursive calls into kmemleak. + */ + if (flags & SLAB_NOLEAKTRACE) + return false; + + /* + * Size is large, assume best to place the slab management obj + * off-slab (should allow better packing of objs). + */ + left = calculate_slab_order(cachep, size, flags | CFLGS_OFF_SLAB); + if (!cachep->num) + return false; + + /* + * If the slab has been placed off-slab, and we have enough space then + * move it on-slab. This is at the expense of any extra colouring. + */ + if (left >= cachep->num * sizeof(freelist_idx_t)) + return false; + + cachep->colour = left / cachep->colour_off; + + return true; +} + +static bool set_on_slab_cache(struct kmem_cache *cachep, + size_t size, slab_flags_t flags) +{ + size_t left; + + cachep->num = 0; + + left = calculate_slab_order(cachep, size, flags); + if (!cachep->num) + return false; + + cachep->colour = left / cachep->colour_off; + + return true; +} + +/** + * __kmem_cache_create - Create a cache. + * @cachep: cache management descriptor + * @flags: SLAB flags + * + * Returns a ptr to the cache on success, NULL on failure. + * Cannot be called within a int, 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. + * + * Return: a pointer to the created cache or %NULL in case of error + */ +int __kmem_cache_create(struct kmem_cache *cachep, slab_flags_t flags) +{ + size_t ralign = BYTES_PER_WORD; + gfp_t gfp; + int err; + unsigned int size = cachep->size; + +#if DEBUG +#if FORCED_DEBUG + /* + * Enable redzoning and last user accounting, except for caches with + * large objects, if the increased size would increase the object size + * above the next power of two: caches with object sizes just above a + * power of two have a significant amount of internal fragmentation. + */ + if (size < 4096 || fls(size - 1) == fls(size-1 + REDZONE_ALIGN + + 2 * sizeof(unsigned long long))) + flags |= SLAB_RED_ZONE | SLAB_STORE_USER; + if (!(flags & SLAB_TYPESAFE_BY_RCU)) + flags |= SLAB_POISON; +#endif +#endif + + /* + * Check that size is in terms of words. This is needed to avoid + * unaligned accesses for some archs when redzoning is used, and makes + * sure any on-slab bufctl's are also correctly aligned. + */ + size = ALIGN(size, BYTES_PER_WORD); + + if (flags & SLAB_RED_ZONE) { + ralign = REDZONE_ALIGN; + /* If redzoning, ensure that the second redzone is suitably + * aligned, by adjusting the object size accordingly. */ + size = ALIGN(size, REDZONE_ALIGN); + } + + /* 3) caller mandated alignment */ + if (ralign < cachep->align) { + ralign = cachep->align; + } + /* disable debug if necessary */ + if (ralign > __alignof__(unsigned long long)) + flags &= ~(SLAB_RED_ZONE | SLAB_STORE_USER); + /* + * 4) Store it. + */ + cachep->align = ralign; + cachep->colour_off = cache_line_size(); + /* Offset must be a multiple of the alignment. */ + if (cachep->colour_off < cachep->align) + cachep->colour_off = cachep->align; + + if (slab_is_available()) + gfp = GFP_KERNEL; + else + gfp = GFP_NOWAIT; + +#if DEBUG + + /* + * Both debugging options require word-alignment which is calculated + * into align above. + */ + if (flags & SLAB_RED_ZONE) { + /* add space for red zone words */ + cachep->obj_offset += sizeof(unsigned long long); + size += 2 * sizeof(unsigned long long); + } + if (flags & SLAB_STORE_USER) { + /* user store requires one word storage behind the end of + * the real object. But if the second red zone needs to be + * aligned to 64 bits, we must allow that much space. + */ + if (flags & SLAB_RED_ZONE) + size += REDZONE_ALIGN; + else + size += BYTES_PER_WORD; + } +#endif + + kasan_cache_create(cachep, &size, &flags); + + size = ALIGN(size, cachep->align); + /* + * We should restrict the number of objects in a slab to implement + * byte sized index. Refer comment on SLAB_OBJ_MIN_SIZE definition. + */ + if (FREELIST_BYTE_INDEX && size < SLAB_OBJ_MIN_SIZE) + size = ALIGN(SLAB_OBJ_MIN_SIZE, cachep->align); + +#if DEBUG + /* + * To activate debug pagealloc, off-slab management is necessary + * requirement. In early phase of initialization, small sized slab + * doesn't get initialized so it would not be possible. So, we need + * to check size >= 256. It guarantees that all necessary small + * sized slab is initialized in current slab initialization sequence. + */ + if (debug_pagealloc_enabled_static() && (flags & SLAB_POISON) && + size >= 256 && cachep->object_size > cache_line_size()) { + if (size < PAGE_SIZE || size % PAGE_SIZE == 0) { + size_t tmp_size = ALIGN(size, PAGE_SIZE); + + if (set_off_slab_cache(cachep, tmp_size, flags)) { + flags |= CFLGS_OFF_SLAB; + cachep->obj_offset += tmp_size - size; + size = tmp_size; + goto done; + } + } + } +#endif + + if (set_objfreelist_slab_cache(cachep, size, flags)) { + flags |= CFLGS_OBJFREELIST_SLAB; + goto done; + } + + if (set_off_slab_cache(cachep, size, flags)) { + flags |= CFLGS_OFF_SLAB; + goto done; + } + + if (set_on_slab_cache(cachep, size, flags)) + goto done; + + return -E2BIG; + +done: + cachep->freelist_size = cachep->num * sizeof(freelist_idx_t); + cachep->flags = flags; + cachep->allocflags = __GFP_COMP; + if (flags & SLAB_CACHE_DMA) + cachep->allocflags |= GFP_DMA; + if (flags & SLAB_CACHE_DMA32) + cachep->allocflags |= GFP_DMA32; + if (flags & SLAB_RECLAIM_ACCOUNT) + cachep->allocflags |= __GFP_RECLAIMABLE; + cachep->size = size; + cachep->reciprocal_buffer_size = reciprocal_value(size); + +#if DEBUG + /* + * If we're going to use the generic kernel_map_pages() + * poisoning, then it's going to smash the contents of + * the redzone and userword anyhow, so switch them off. + */ + if (IS_ENABLED(CONFIG_PAGE_POISONING) && + (cachep->flags & SLAB_POISON) && + is_debug_pagealloc_cache(cachep)) + cachep->flags &= ~(SLAB_RED_ZONE | SLAB_STORE_USER); +#endif + + if (OFF_SLAB(cachep)) { + cachep->freelist_cache = + kmalloc_slab(cachep->freelist_size, 0u); + } + + err = setup_cpu_cache(cachep, gfp); + if (err) { + __kmem_cache_release(cachep); + return err; + } + + return 0; +} + +#if DEBUG +static void check_irq_off(void) +{ + BUG_ON(!irqs_disabled()); +} + +static void check_irq_on(void) +{ + BUG_ON(irqs_disabled()); +} + +static void check_mutex_acquired(void) +{ + BUG_ON(!mutex_is_locked(&slab_mutex)); +} + +static void check_spinlock_acquired(struct kmem_cache *cachep) +{ +#ifdef CONFIG_SMP + check_irq_off(); + assert_spin_locked(&get_node(cachep, numa_mem_id())->list_lock); +#endif +} + +static void check_spinlock_acquired_node(struct kmem_cache *cachep, int node) +{ +#ifdef CONFIG_SMP + check_irq_off(); + assert_spin_locked(&get_node(cachep, node)->list_lock); +#endif +} + +#else +#define check_irq_off() do { } while(0) +#define check_irq_on() do { } while(0) +#define check_mutex_acquired() do { } while(0) +#define check_spinlock_acquired(x) do { } while(0) +#define check_spinlock_acquired_node(x, y) do { } while(0) +#endif + +static void drain_array_locked(struct kmem_cache *cachep, struct array_cache *ac, + int node, bool free_all, struct list_head *list) +{ + int tofree; + + if (!ac || !ac->avail) + return; + + tofree = free_all ? ac->avail : (ac->limit + 4) / 5; + if (tofree > ac->avail) + tofree = (ac->avail + 1) / 2; + + free_block(cachep, ac->entry, tofree, node, list); + ac->avail -= tofree; + memmove(ac->entry, &(ac->entry[tofree]), sizeof(void *) * ac->avail); +} + +static void do_drain(void *arg) +{ + struct kmem_cache *cachep = arg; + struct array_cache *ac; + int node = numa_mem_id(); + struct kmem_cache_node *n; + LIST_HEAD(list); + + check_irq_off(); + ac = cpu_cache_get(cachep); + n = get_node(cachep, node); + spin_lock(&n->list_lock); + free_block(cachep, ac->entry, ac->avail, node, &list); + spin_unlock(&n->list_lock); + ac->avail = 0; + slabs_destroy(cachep, &list); +} + +static void drain_cpu_caches(struct kmem_cache *cachep) +{ + struct kmem_cache_node *n; + int node; + LIST_HEAD(list); + + on_each_cpu(do_drain, cachep, 1); + check_irq_on(); + for_each_kmem_cache_node(cachep, node, n) + if (n->alien) + drain_alien_cache(cachep, n->alien); + + for_each_kmem_cache_node(cachep, node, n) { + spin_lock_irq(&n->list_lock); + drain_array_locked(cachep, n->shared, node, true, &list); + spin_unlock_irq(&n->list_lock); + + slabs_destroy(cachep, &list); + } +} + +/* + * Remove slabs from the list of free slabs. + * Specify the number of slabs to drain in tofree. + * + * Returns the actual number of slabs released. + */ +static int drain_freelist(struct kmem_cache *cache, + struct kmem_cache_node *n, int tofree) +{ + struct list_head *p; + int nr_freed; + struct page *page; + + nr_freed = 0; + while (nr_freed < tofree && !list_empty(&n->slabs_free)) { + + spin_lock_irq(&n->list_lock); + p = n->slabs_free.prev; + if (p == &n->slabs_free) { + spin_unlock_irq(&n->list_lock); + goto out; + } + + page = list_entry(p, struct page, slab_list); + list_del(&page->slab_list); + n->free_slabs--; + n->total_slabs--; + /* + * Safe to drop the lock. The slab is no longer linked + * to the cache. + */ + n->free_objects -= cache->num; + spin_unlock_irq(&n->list_lock); + slab_destroy(cache, page); + nr_freed++; + } +out: + return nr_freed; +} + +bool __kmem_cache_empty(struct kmem_cache *s) +{ + int node; + struct kmem_cache_node *n; + + for_each_kmem_cache_node(s, node, n) + if (!list_empty(&n->slabs_full) || + !list_empty(&n->slabs_partial)) + return false; + return true; +} + +int __kmem_cache_shrink(struct kmem_cache *cachep) +{ + int ret = 0; + int node; + struct kmem_cache_node *n; + + drain_cpu_caches(cachep); + + check_irq_on(); + for_each_kmem_cache_node(cachep, node, n) { + drain_freelist(cachep, n, INT_MAX); + + ret += !list_empty(&n->slabs_full) || + !list_empty(&n->slabs_partial); + } + return (ret ? 1 : 0); +} + +int __kmem_cache_shutdown(struct kmem_cache *cachep) +{ + return __kmem_cache_shrink(cachep); +} + +void __kmem_cache_release(struct kmem_cache *cachep) +{ + int i; + struct kmem_cache_node *n; + + cache_random_seq_destroy(cachep); + + free_percpu(cachep->cpu_cache); + + /* NUMA: free the node structures */ + for_each_kmem_cache_node(cachep, i, n) { + kfree(n->shared); + free_alien_cache(n->alien); + kfree(n); + cachep->node[i] = NULL; + } +} + +/* + * Get the memory for a slab management obj. + * + * For a slab cache when the slab descriptor is off-slab, the + * slab descriptor can't come from the same cache which is being created, + * Because if it is the case, that means we defer the creation of + * the kmalloc_{dma,}_cache of size sizeof(slab descriptor) to this point. + * And we eventually call down to __kmem_cache_create(), which + * in turn looks up in the kmalloc_{dma,}_caches for the disired-size one. + * This is a "chicken-and-egg" problem. + * + * So the off-slab slab descriptor shall come from the kmalloc_{dma,}_caches, + * which are all initialized during kmem_cache_init(). + */ +static void *alloc_slabmgmt(struct kmem_cache *cachep, + struct page *page, int colour_off, + gfp_t local_flags, int nodeid) +{ + void *freelist; + void *addr = page_address(page); + + page->s_mem = addr + colour_off; + page->active = 0; + + if (OBJFREELIST_SLAB(cachep)) + freelist = NULL; + else if (OFF_SLAB(cachep)) { + /* Slab management obj is off-slab. */ + freelist = kmem_cache_alloc_node(cachep->freelist_cache, + local_flags, nodeid); + } else { + /* We will use last bytes at the slab for freelist */ + freelist = addr + (PAGE_SIZE << cachep->gfporder) - + cachep->freelist_size; + } + + return freelist; +} + +static inline freelist_idx_t get_free_obj(struct page *page, unsigned int idx) +{ + return ((freelist_idx_t *)page->freelist)[idx]; +} + +static inline void set_free_obj(struct page *page, + unsigned int idx, freelist_idx_t val) +{ + ((freelist_idx_t *)(page->freelist))[idx] = val; +} + +static void cache_init_objs_debug(struct kmem_cache *cachep, struct page *page) +{ +#if DEBUG + int i; + + for (i = 0; i < cachep->num; i++) { + void *objp = index_to_obj(cachep, page, i); + + if (cachep->flags & SLAB_STORE_USER) + *dbg_userword(cachep, objp) = NULL; + + if (cachep->flags & SLAB_RED_ZONE) { + *dbg_redzone1(cachep, objp) = RED_INACTIVE; + *dbg_redzone2(cachep, objp) = RED_INACTIVE; + } + /* + * Constructors are not allowed to allocate memory from the same + * cache which they are a constructor for. Otherwise, deadlock. + * They must also be threaded. + */ + if (cachep->ctor && !(cachep->flags & SLAB_POISON)) { + kasan_unpoison_object_data(cachep, + objp + obj_offset(cachep)); + cachep->ctor(objp + obj_offset(cachep)); + kasan_poison_object_data( + cachep, objp + obj_offset(cachep)); + } + + if (cachep->flags & SLAB_RED_ZONE) { + if (*dbg_redzone2(cachep, objp) != RED_INACTIVE) + slab_error(cachep, "constructor overwrote the end of an object"); + if (*dbg_redzone1(cachep, objp) != RED_INACTIVE) + slab_error(cachep, "constructor overwrote the start of an object"); + } + /* need to poison the objs? */ + if (cachep->flags & SLAB_POISON) { + poison_obj(cachep, objp, POISON_FREE); + slab_kernel_map(cachep, objp, 0); + } + } +#endif +} + +#ifdef CONFIG_SLAB_FREELIST_RANDOM +/* Hold information during a freelist initialization */ +union freelist_init_state { + struct { + unsigned int pos; + unsigned int *list; + unsigned int count; + }; + struct rnd_state rnd_state; +}; + +/* + * Initialize the state based on the randomization methode available. + * return true if the pre-computed list is available, false otherwize. + */ +static bool freelist_state_initialize(union freelist_init_state *state, + struct kmem_cache *cachep, + unsigned int count) +{ + bool ret; + unsigned int rand; + + /* Use best entropy available to define a random shift */ + rand = get_random_int(); + + /* Use a random state if the pre-computed list is not available */ + if (!cachep->random_seq) { + prandom_seed_state(&state->rnd_state, rand); + ret = false; + } else { + state->list = cachep->random_seq; + state->count = count; + state->pos = rand % count; + ret = true; + } + return ret; +} + +/* Get the next entry on the list and randomize it using a random shift */ +static freelist_idx_t next_random_slot(union freelist_init_state *state) +{ + if (state->pos >= state->count) + state->pos = 0; + return state->list[state->pos++]; +} + +/* Swap two freelist entries */ +static void swap_free_obj(struct page *page, unsigned int a, unsigned int b) +{ + swap(((freelist_idx_t *)page->freelist)[a], + ((freelist_idx_t *)page->freelist)[b]); +} + +/* + * Shuffle the freelist initialization state based on pre-computed lists. + * return true if the list was successfully shuffled, false otherwise. + */ +static bool shuffle_freelist(struct kmem_cache *cachep, struct page *page) +{ + unsigned int objfreelist = 0, i, rand, count = cachep->num; + union freelist_init_state state; + bool precomputed; + + if (count < 2) + return false; + + precomputed = freelist_state_initialize(&state, cachep, count); + + /* Take a random entry as the objfreelist */ + if (OBJFREELIST_SLAB(cachep)) { + if (!precomputed) + objfreelist = count - 1; + else + objfreelist = next_random_slot(&state); + page->freelist = index_to_obj(cachep, page, objfreelist) + + obj_offset(cachep); + count--; + } + + /* + * On early boot, generate the list dynamically. + * Later use a pre-computed list for speed. + */ + if (!precomputed) { + for (i = 0; i < count; i++) + set_free_obj(page, i, i); + + /* Fisher-Yates shuffle */ + for (i = count - 1; i > 0; i--) { + rand = prandom_u32_state(&state.rnd_state); + rand %= (i + 1); + swap_free_obj(page, i, rand); + } + } else { + for (i = 0; i < count; i++) + set_free_obj(page, i, next_random_slot(&state)); + } + + if (OBJFREELIST_SLAB(cachep)) + set_free_obj(page, cachep->num - 1, objfreelist); + + return true; +} +#else +static inline bool shuffle_freelist(struct kmem_cache *cachep, + struct page *page) +{ + return false; +} +#endif /* CONFIG_SLAB_FREELIST_RANDOM */ + +static void cache_init_objs(struct kmem_cache *cachep, + struct page *page) +{ + int i; + void *objp; + bool shuffled; + + cache_init_objs_debug(cachep, page); + + /* Try to randomize the freelist if enabled */ + shuffled = shuffle_freelist(cachep, page); + + if (!shuffled && OBJFREELIST_SLAB(cachep)) { + page->freelist = index_to_obj(cachep, page, cachep->num - 1) + + obj_offset(cachep); + } + + for (i = 0; i < cachep->num; i++) { + objp = index_to_obj(cachep, page, i); + objp = kasan_init_slab_obj(cachep, objp); + + /* constructor could break poison info */ + if (DEBUG == 0 && cachep->ctor) { + kasan_unpoison_object_data(cachep, objp); + cachep->ctor(objp); + kasan_poison_object_data(cachep, objp); + } + + if (!shuffled) + set_free_obj(page, i, i); + } +} + +static void *slab_get_obj(struct kmem_cache *cachep, struct page *page) +{ + void *objp; + + objp = index_to_obj(cachep, page, get_free_obj(page, page->active)); + page->active++; + + return objp; +} + +static void slab_put_obj(struct kmem_cache *cachep, + struct page *page, void *objp) +{ + unsigned int objnr = obj_to_index(cachep, page, objp); +#if DEBUG + unsigned int i; + + /* Verify double free bug */ + for (i = page->active; i < cachep->num; i++) { + if (get_free_obj(page, i) == objnr) { + pr_err("slab: double free detected in cache '%s', objp %px\n", + cachep->name, objp); + BUG(); + } + } +#endif + page->active--; + if (!page->freelist) + page->freelist = objp + obj_offset(cachep); + + set_free_obj(page, page->active, objnr); +} + +/* + * Map pages beginning at addr to the given cache and slab. This is required + * for the slab allocator to be able to lookup the cache and slab of a + * virtual address for kfree, ksize, and slab debugging. + */ +static void slab_map_pages(struct kmem_cache *cache, struct page *page, + void *freelist) +{ + page->slab_cache = cache; + page->freelist = freelist; +} + +/* + * Grow (by 1) the number of slabs within a cache. This is called by + * kmem_cache_alloc() when there are no active objs left in a cache. + */ +static struct page *cache_grow_begin(struct kmem_cache *cachep, + gfp_t flags, int nodeid) +{ + void *freelist; + size_t offset; + gfp_t local_flags; + int page_node; + struct kmem_cache_node *n; + struct page *page; + + /* + * Be lazy and only check for valid flags here, keeping it out of the + * critical path in kmem_cache_alloc(). + */ + if (unlikely(flags & GFP_SLAB_BUG_MASK)) + flags = kmalloc_fix_flags(flags); + + WARN_ON_ONCE(cachep->ctor && (flags & __GFP_ZERO)); + local_flags = flags & (GFP_CONSTRAINT_MASK|GFP_RECLAIM_MASK); + + check_irq_off(); + if (gfpflags_allow_blocking(local_flags)) + local_irq_enable(); + + /* + * Get mem for the objs. Attempt to allocate a physical page from + * 'nodeid'. + */ + page = kmem_getpages(cachep, local_flags, nodeid); + if (!page) + goto failed; + + page_node = page_to_nid(page); + n = get_node(cachep, page_node); + + /* Get colour for the slab, and cal the next value. */ + n->colour_next++; + if (n->colour_next >= cachep->colour) + n->colour_next = 0; + + offset = n->colour_next; + if (offset >= cachep->colour) + offset = 0; + + offset *= cachep->colour_off; + + /* + * Call kasan_poison_slab() before calling alloc_slabmgmt(), so + * page_address() in the latter returns a non-tagged pointer, + * as it should be for slab pages. + */ + kasan_poison_slab(page); + + /* Get slab management. */ + freelist = alloc_slabmgmt(cachep, page, offset, + local_flags & ~GFP_CONSTRAINT_MASK, page_node); + if (OFF_SLAB(cachep) && !freelist) + goto opps1; + + slab_map_pages(cachep, page, freelist); + + cache_init_objs(cachep, page); + + if (gfpflags_allow_blocking(local_flags)) + local_irq_disable(); + + return page; + +opps1: + kmem_freepages(cachep, page); +failed: + if (gfpflags_allow_blocking(local_flags)) + local_irq_disable(); + return NULL; +} + +static void cache_grow_end(struct kmem_cache *cachep, struct page *page) +{ + struct kmem_cache_node *n; + void *list = NULL; + + check_irq_off(); + + if (!page) + return; + + INIT_LIST_HEAD(&page->slab_list); + n = get_node(cachep, page_to_nid(page)); + + spin_lock(&n->list_lock); + n->total_slabs++; + if (!page->active) { + list_add_tail(&page->slab_list, &n->slabs_free); + n->free_slabs++; + } else + fixup_slab_list(cachep, n, page, &list); + + STATS_INC_GROWN(cachep); + n->free_objects += cachep->num - page->active; + spin_unlock(&n->list_lock); + + fixup_objfreelist_debug(cachep, &list); +} + +#if DEBUG + +/* + * Perform extra freeing checks: + * - detect bad pointers. + * - POISON/RED_ZONE checking + */ +static void kfree_debugcheck(const void *objp) +{ + if (!virt_addr_valid(objp)) { + pr_err("kfree_debugcheck: out of range ptr %lxh\n", + (unsigned long)objp); + BUG(); + } +} + +static inline void verify_redzone_free(struct kmem_cache *cache, void *obj) +{ + unsigned long long redzone1, redzone2; + + redzone1 = *dbg_redzone1(cache, obj); + redzone2 = *dbg_redzone2(cache, obj); + + /* + * Redzone is ok. + */ + if (redzone1 == RED_ACTIVE && redzone2 == RED_ACTIVE) + return; + + if (redzone1 == RED_INACTIVE && redzone2 == RED_INACTIVE) + slab_error(cache, "double free detected"); + else + slab_error(cache, "memory outside object was overwritten"); + + pr_err("%px: redzone 1:0x%llx, redzone 2:0x%llx\n", + obj, redzone1, redzone2); +} + +static void *cache_free_debugcheck(struct kmem_cache *cachep, void *objp, + unsigned long caller) +{ + unsigned int objnr; + struct page *page; + + BUG_ON(virt_to_cache(objp) != cachep); + + objp -= obj_offset(cachep); + kfree_debugcheck(objp); + page = virt_to_head_page(objp); + + if (cachep->flags & SLAB_RED_ZONE) { + verify_redzone_free(cachep, objp); + *dbg_redzone1(cachep, objp) = RED_INACTIVE; + *dbg_redzone2(cachep, objp) = RED_INACTIVE; + } + if (cachep->flags & SLAB_STORE_USER) + *dbg_userword(cachep, objp) = (void *)caller; + + objnr = obj_to_index(cachep, page, objp); + + BUG_ON(objnr >= cachep->num); + BUG_ON(objp != index_to_obj(cachep, page, objnr)); + + if (cachep->flags & SLAB_POISON) { + poison_obj(cachep, objp, POISON_FREE); + slab_kernel_map(cachep, objp, 0); + } + return objp; +} + +#else +#define kfree_debugcheck(x) do { } while(0) +#define cache_free_debugcheck(x,objp,z) (objp) +#endif + +static inline void fixup_objfreelist_debug(struct kmem_cache *cachep, + void **list) +{ +#if DEBUG + void *next = *list; + void *objp; + + while (next) { + objp = next - obj_offset(cachep); + next = *(void **)next; + poison_obj(cachep, objp, POISON_FREE); + } +#endif +} + +static inline void fixup_slab_list(struct kmem_cache *cachep, + struct kmem_cache_node *n, struct page *page, + void **list) +{ + /* move slabp to correct slabp list: */ + list_del(&page->slab_list); + if (page->active == cachep->num) { + list_add(&page->slab_list, &n->slabs_full); + if (OBJFREELIST_SLAB(cachep)) { +#if DEBUG + /* Poisoning will be done without holding the lock */ + if (cachep->flags & SLAB_POISON) { + void **objp = page->freelist; + + *objp = *list; + *list = objp; + } +#endif + page->freelist = NULL; + } + } else + list_add(&page->slab_list, &n->slabs_partial); +} + +/* Try to find non-pfmemalloc slab if needed */ +static noinline struct page *get_valid_first_slab(struct kmem_cache_node *n, + struct page *page, bool pfmemalloc) +{ + if (!page) + return NULL; + + if (pfmemalloc) + return page; + + if (!PageSlabPfmemalloc(page)) + return page; + + /* No need to keep pfmemalloc slab if we have enough free objects */ + if (n->free_objects > n->free_limit) { + ClearPageSlabPfmemalloc(page); + return page; + } + + /* Move pfmemalloc slab to the end of list to speed up next search */ + list_del(&page->slab_list); + if (!page->active) { + list_add_tail(&page->slab_list, &n->slabs_free); + n->free_slabs++; + } else + list_add_tail(&page->slab_list, &n->slabs_partial); + + list_for_each_entry(page, &n->slabs_partial, slab_list) { + if (!PageSlabPfmemalloc(page)) + return page; + } + + n->free_touched = 1; + list_for_each_entry(page, &n->slabs_free, slab_list) { + if (!PageSlabPfmemalloc(page)) { + n->free_slabs--; + return page; + } + } + + return NULL; +} + +static struct page *get_first_slab(struct kmem_cache_node *n, bool pfmemalloc) +{ + struct page *page; + + assert_spin_locked(&n->list_lock); + page = list_first_entry_or_null(&n->slabs_partial, struct page, + slab_list); + if (!page) { + n->free_touched = 1; + page = list_first_entry_or_null(&n->slabs_free, struct page, + slab_list); + if (page) + n->free_slabs--; + } + + if (sk_memalloc_socks()) + page = get_valid_first_slab(n, page, pfmemalloc); + + return page; +} + +static noinline void *cache_alloc_pfmemalloc(struct kmem_cache *cachep, + struct kmem_cache_node *n, gfp_t flags) +{ + struct page *page; + void *obj; + void *list = NULL; + + if (!gfp_pfmemalloc_allowed(flags)) + return NULL; + + spin_lock(&n->list_lock); + page = get_first_slab(n, true); + if (!page) { + spin_unlock(&n->list_lock); + return NULL; + } + + obj = slab_get_obj(cachep, page); + n->free_objects--; + + fixup_slab_list(cachep, n, page, &list); + + spin_unlock(&n->list_lock); + fixup_objfreelist_debug(cachep, &list); + + return obj; +} + +/* + * Slab list should be fixed up by fixup_slab_list() for existing slab + * or cache_grow_end() for new slab + */ +static __always_inline int alloc_block(struct kmem_cache *cachep, + struct array_cache *ac, struct page *page, int batchcount) +{ + /* + * There must be at least one object available for + * allocation. + */ + BUG_ON(page->active >= cachep->num); + + while (page->active < cachep->num && batchcount--) { + STATS_INC_ALLOCED(cachep); + STATS_INC_ACTIVE(cachep); + STATS_SET_HIGH(cachep); + + ac->entry[ac->avail++] = slab_get_obj(cachep, page); + } + + return batchcount; +} + +static void *cache_alloc_refill(struct kmem_cache *cachep, gfp_t flags) +{ + int batchcount; + struct kmem_cache_node *n; + struct array_cache *ac, *shared; + int node; + void *list = NULL; + struct page *page; + + check_irq_off(); + node = numa_mem_id(); + + ac = cpu_cache_get(cachep); + batchcount = ac->batchcount; + if (!ac->touched && batchcount > BATCHREFILL_LIMIT) { + /* + * If there was little recent activity on this cache, then + * perform only a partial refill. Otherwise we could generate + * refill bouncing. + */ + batchcount = BATCHREFILL_LIMIT; + } + n = get_node(cachep, node); + + BUG_ON(ac->avail > 0 || !n); + shared = READ_ONCE(n->shared); + if (!n->free_objects && (!shared || !shared->avail)) + goto direct_grow; + + spin_lock(&n->list_lock); + shared = READ_ONCE(n->shared); + + /* See if we can refill from the shared array */ + if (shared && transfer_objects(ac, shared, batchcount)) { + shared->touched = 1; + goto alloc_done; + } + + while (batchcount > 0) { + /* Get slab alloc is to come from. */ + page = get_first_slab(n, false); + if (!page) + goto must_grow; + + check_spinlock_acquired(cachep); + + batchcount = alloc_block(cachep, ac, page, batchcount); + fixup_slab_list(cachep, n, page, &list); + } + +must_grow: + n->free_objects -= ac->avail; +alloc_done: + spin_unlock(&n->list_lock); + fixup_objfreelist_debug(cachep, &list); + +direct_grow: + if (unlikely(!ac->avail)) { + /* Check if we can use obj in pfmemalloc slab */ + if (sk_memalloc_socks()) { + void *obj = cache_alloc_pfmemalloc(cachep, n, flags); + + if (obj) + return obj; + } + + page = cache_grow_begin(cachep, gfp_exact_node(flags), node); + + /* + * cache_grow_begin() can reenable interrupts, + * then ac could change. + */ + ac = cpu_cache_get(cachep); + if (!ac->avail && page) + alloc_block(cachep, ac, page, batchcount); + cache_grow_end(cachep, page); + + if (!ac->avail) + return NULL; + } + ac->touched = 1; + + return ac->entry[--ac->avail]; +} + +static inline void cache_alloc_debugcheck_before(struct kmem_cache *cachep, + gfp_t flags) +{ + might_sleep_if(gfpflags_allow_blocking(flags)); +} + +#if DEBUG +static void *cache_alloc_debugcheck_after(struct kmem_cache *cachep, + gfp_t flags, void *objp, unsigned long caller) +{ + WARN_ON_ONCE(cachep->ctor && (flags & __GFP_ZERO)); + if (!objp) + return objp; + if (cachep->flags & SLAB_POISON) { + check_poison_obj(cachep, objp); + slab_kernel_map(cachep, objp, 1); + poison_obj(cachep, objp, POISON_INUSE); + } + if (cachep->flags & SLAB_STORE_USER) + *dbg_userword(cachep, objp) = (void *)caller; + + if (cachep->flags & SLAB_RED_ZONE) { + if (*dbg_redzone1(cachep, objp) != RED_INACTIVE || + *dbg_redzone2(cachep, objp) != RED_INACTIVE) { + slab_error(cachep, "double free, or memory outside object was overwritten"); + pr_err("%px: redzone 1:0x%llx, redzone 2:0x%llx\n", + objp, *dbg_redzone1(cachep, objp), + *dbg_redzone2(cachep, objp)); + } + *dbg_redzone1(cachep, objp) = RED_ACTIVE; + *dbg_redzone2(cachep, objp) = RED_ACTIVE; + } + + objp += obj_offset(cachep); + if (cachep->ctor && cachep->flags & SLAB_POISON) + cachep->ctor(objp); + if (ARCH_SLAB_MINALIGN && + ((unsigned long)objp & (ARCH_SLAB_MINALIGN-1))) { + pr_err("0x%px: not aligned to ARCH_SLAB_MINALIGN=%d\n", + objp, (int)ARCH_SLAB_MINALIGN); + } + return objp; +} +#else +#define cache_alloc_debugcheck_after(a,b,objp,d) (objp) +#endif + +static inline void *____cache_alloc(struct kmem_cache *cachep, gfp_t flags) +{ + void *objp; + struct array_cache *ac; + + check_irq_off(); + + ac = cpu_cache_get(cachep); + if (likely(ac->avail)) { + ac->touched = 1; + objp = ac->entry[--ac->avail]; + + STATS_INC_ALLOCHIT(cachep); + goto out; + } + + STATS_INC_ALLOCMISS(cachep); + objp = cache_alloc_refill(cachep, flags); + /* + * the 'ac' may be updated by cache_alloc_refill(), + * and kmemleak_erase() requires its correct value. + */ + ac = cpu_cache_get(cachep); + +out: + /* + * To avoid a false negative, if an object that is in one of the + * per-CPU caches is leaked, we need to make sure kmemleak doesn't + * treat the array pointers as a reference to the object. + */ + if (objp) + kmemleak_erase(&ac->entry[ac->avail]); + return objp; +} + +#ifdef CONFIG_NUMA +/* + * Try allocating on another node if PFA_SPREAD_SLAB is a mempolicy is set. + * + * If we are in_interrupt, then process context, including cpusets and + * mempolicy, may not apply and should not be used for allocation policy. + */ +static void *alternate_node_alloc(struct kmem_cache *cachep, gfp_t flags) +{ + int nid_alloc, nid_here; + + if (in_interrupt() || (flags & __GFP_THISNODE)) + return NULL; + nid_alloc = nid_here = numa_mem_id(); + if (cpuset_do_slab_mem_spread() && (cachep->flags & SLAB_MEM_SPREAD)) + nid_alloc = cpuset_slab_spread_node(); + else if (current->mempolicy) + nid_alloc = mempolicy_slab_node(); + if (nid_alloc != nid_here) + return ____cache_alloc_node(cachep, flags, nid_alloc); + return NULL; +} + +/* + * Fallback function if there was no memory available and no objects on a + * certain node and fall back is permitted. First we scan all the + * available node for available objects. If that fails then we + * perform an allocation without specifying a node. This allows the page + * allocator to do its reclaim / fallback magic. We then insert the + * slab into the proper nodelist and then allocate from it. + */ +static void *fallback_alloc(struct kmem_cache *cache, gfp_t flags) +{ + struct zonelist *zonelist; + struct zoneref *z; + struct zone *zone; + enum zone_type highest_zoneidx = gfp_zone(flags); + void *obj = NULL; + struct page *page; + int nid; + unsigned int cpuset_mems_cookie; + + if (flags & __GFP_THISNODE) + return NULL; + +retry_cpuset: + cpuset_mems_cookie = read_mems_allowed_begin(); + zonelist = node_zonelist(mempolicy_slab_node(), flags); + +retry: + /* + * Look through allowed nodes for objects available + * from existing per node queues. + */ + for_each_zone_zonelist(zone, z, zonelist, highest_zoneidx) { + nid = zone_to_nid(zone); + + if (cpuset_zone_allowed(zone, flags) && + get_node(cache, nid) && + get_node(cache, nid)->free_objects) { + obj = ____cache_alloc_node(cache, + gfp_exact_node(flags), nid); + if (obj) + break; + } + } + + if (!obj) { + /* + * This allocation will be performed within the constraints + * of the current cpuset / memory policy requirements. + * We may trigger various forms of reclaim on the allowed + * set and go into memory reserves if necessary. + */ + page = cache_grow_begin(cache, flags, numa_mem_id()); + cache_grow_end(cache, page); + if (page) { + nid = page_to_nid(page); + obj = ____cache_alloc_node(cache, + gfp_exact_node(flags), nid); + + /* + * Another processor may allocate the objects in + * the slab since we are not holding any locks. + */ + if (!obj) + goto retry; + } + } + + if (unlikely(!obj && read_mems_allowed_retry(cpuset_mems_cookie))) + goto retry_cpuset; + return obj; +} + +/* + * A interface to enable slab creation on nodeid + */ +static void *____cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, + int nodeid) +{ + struct page *page; + struct kmem_cache_node *n; + void *obj = NULL; + void *list = NULL; + + VM_BUG_ON(nodeid < 0 || nodeid >= MAX_NUMNODES); + n = get_node(cachep, nodeid); + BUG_ON(!n); + + check_irq_off(); + spin_lock(&n->list_lock); + page = get_first_slab(n, false); + if (!page) + goto must_grow; + + check_spinlock_acquired_node(cachep, nodeid); + + STATS_INC_NODEALLOCS(cachep); + STATS_INC_ACTIVE(cachep); + STATS_SET_HIGH(cachep); + + BUG_ON(page->active == cachep->num); + + obj = slab_get_obj(cachep, page); + n->free_objects--; + + fixup_slab_list(cachep, n, page, &list); + + spin_unlock(&n->list_lock); + fixup_objfreelist_debug(cachep, &list); + return obj; + +must_grow: + spin_unlock(&n->list_lock); + page = cache_grow_begin(cachep, gfp_exact_node(flags), nodeid); + if (page) { + /* This slab isn't counted yet so don't update free_objects */ + obj = slab_get_obj(cachep, page); + } + cache_grow_end(cachep, page); + + return obj ? obj : fallback_alloc(cachep, flags); +} + +static __always_inline void * +slab_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid, + unsigned long caller) +{ + unsigned long save_flags; + void *ptr; + int slab_node = numa_mem_id(); + struct obj_cgroup *objcg = NULL; + + flags &= gfp_allowed_mask; + cachep = slab_pre_alloc_hook(cachep, &objcg, 1, flags); + if (unlikely(!cachep)) + return NULL; + + cache_alloc_debugcheck_before(cachep, flags); + local_irq_save(save_flags); + + if (nodeid == NUMA_NO_NODE) + nodeid = slab_node; + + if (unlikely(!get_node(cachep, nodeid))) { + /* Node not bootstrapped yet */ + ptr = fallback_alloc(cachep, flags); + goto out; + } + + if (nodeid == slab_node) { + /* + * Use the locally cached objects if possible. + * However ____cache_alloc does not allow fallback + * to other nodes. It may fail while we still have + * objects on other nodes available. + */ + ptr = ____cache_alloc(cachep, flags); + if (ptr) + goto out; + } + /* ___cache_alloc_node can fall back to other nodes */ + ptr = ____cache_alloc_node(cachep, flags, nodeid); + out: + local_irq_restore(save_flags); + ptr = cache_alloc_debugcheck_after(cachep, flags, ptr, caller); + + if (unlikely(slab_want_init_on_alloc(flags, cachep)) && ptr) + memset(ptr, 0, cachep->object_size); + + slab_post_alloc_hook(cachep, objcg, flags, 1, &ptr); + return ptr; +} + +static __always_inline void * +__do_cache_alloc(struct kmem_cache *cache, gfp_t flags) +{ + void *objp; + + if (current->mempolicy || cpuset_do_slab_mem_spread()) { + objp = alternate_node_alloc(cache, flags); + if (objp) + goto out; + } + objp = ____cache_alloc(cache, flags); + + /* + * We may just have run out of memory on the local node. + * ____cache_alloc_node() knows how to locate memory on other nodes + */ + if (!objp) + objp = ____cache_alloc_node(cache, flags, numa_mem_id()); + + out: + return objp; +} +#else + +static __always_inline void * +__do_cache_alloc(struct kmem_cache *cachep, gfp_t flags) +{ + return ____cache_alloc(cachep, flags); +} + +#endif /* CONFIG_NUMA */ + +static __always_inline void * +slab_alloc(struct kmem_cache *cachep, gfp_t flags, unsigned long caller) +{ + unsigned long save_flags; + void *objp; + struct obj_cgroup *objcg = NULL; + + flags &= gfp_allowed_mask; + cachep = slab_pre_alloc_hook(cachep, &objcg, 1, flags); + if (unlikely(!cachep)) + return NULL; + + cache_alloc_debugcheck_before(cachep, flags); + local_irq_save(save_flags); + objp = __do_cache_alloc(cachep, flags); + local_irq_restore(save_flags); + objp = cache_alloc_debugcheck_after(cachep, flags, objp, caller); + prefetchw(objp); + + if (unlikely(slab_want_init_on_alloc(flags, cachep)) && objp) + memset(objp, 0, cachep->object_size); + + slab_post_alloc_hook(cachep, objcg, flags, 1, &objp); + return objp; +} + +/* + * Caller needs to acquire correct kmem_cache_node's list_lock + * @list: List of detached free slabs should be freed by caller + */ +static void free_block(struct kmem_cache *cachep, void **objpp, + int nr_objects, int node, struct list_head *list) +{ + int i; + struct kmem_cache_node *n = get_node(cachep, node); + struct page *page; + + n->free_objects += nr_objects; + + for (i = 0; i < nr_objects; i++) { + void *objp; + struct page *page; + + objp = objpp[i]; + + page = virt_to_head_page(objp); + list_del(&page->slab_list); + check_spinlock_acquired_node(cachep, node); + slab_put_obj(cachep, page, objp); + STATS_DEC_ACTIVE(cachep); + + /* fixup slab chains */ + if (page->active == 0) { + list_add(&page->slab_list, &n->slabs_free); + n->free_slabs++; + } else { + /* Unconditionally move a slab to the end of the + * partial list on free - maximum time for the + * other objects to be freed, too. + */ + list_add_tail(&page->slab_list, &n->slabs_partial); + } + } + + while (n->free_objects > n->free_limit && !list_empty(&n->slabs_free)) { + n->free_objects -= cachep->num; + + page = list_last_entry(&n->slabs_free, struct page, slab_list); + list_move(&page->slab_list, list); + n->free_slabs--; + n->total_slabs--; + } +} + +static void cache_flusharray(struct kmem_cache *cachep, struct array_cache *ac) +{ + int batchcount; + struct kmem_cache_node *n; + int node = numa_mem_id(); + LIST_HEAD(list); + + batchcount = ac->batchcount; + + check_irq_off(); + n = get_node(cachep, node); + spin_lock(&n->list_lock); + if (n->shared) { + struct array_cache *shared_array = n->shared; + int max = shared_array->limit - shared_array->avail; + if (max) { + if (batchcount > max) + batchcount = max; + memcpy(&(shared_array->entry[shared_array->avail]), + ac->entry, sizeof(void *) * batchcount); + shared_array->avail += batchcount; + goto free_done; + } + } + + free_block(cachep, ac->entry, batchcount, node, &list); +free_done: +#if STATS + { + int i = 0; + struct page *page; + + list_for_each_entry(page, &n->slabs_free, slab_list) { + BUG_ON(page->active); + + i++; + } + STATS_SET_FREEABLE(cachep, i); + } +#endif + spin_unlock(&n->list_lock); + ac->avail -= batchcount; + memmove(ac->entry, &(ac->entry[batchcount]), sizeof(void *)*ac->avail); + slabs_destroy(cachep, &list); +} + +/* + * Release an obj back to its cache. If the obj has a constructed state, it must + * be in this state _before_ it is released. Called with disabled ints. + */ +static __always_inline void __cache_free(struct kmem_cache *cachep, void *objp, + unsigned long caller) +{ + /* Put the object into the quarantine, don't touch it for now. */ + if (kasan_slab_free(cachep, objp, _RET_IP_)) + return; + + /* Use KCSAN to help debug racy use-after-free. */ + if (!(cachep->flags & SLAB_TYPESAFE_BY_RCU)) + __kcsan_check_access(objp, cachep->object_size, + KCSAN_ACCESS_WRITE | KCSAN_ACCESS_ASSERT); + + ___cache_free(cachep, objp, caller); +} + +void ___cache_free(struct kmem_cache *cachep, void *objp, + unsigned long caller) +{ + struct array_cache *ac = cpu_cache_get(cachep); + + check_irq_off(); + if (unlikely(slab_want_init_on_free(cachep))) + memset(objp, 0, cachep->object_size); + kmemleak_free_recursive(objp, cachep->flags); + objp = cache_free_debugcheck(cachep, objp, caller); + memcg_slab_free_hook(cachep, &objp, 1); + + /* + * Skip calling cache_free_alien() when the platform is not numa. + * This will avoid cache misses that happen while accessing slabp (which + * is per page memory reference) to get nodeid. Instead use a global + * variable to skip the call, which is mostly likely to be present in + * the cache. + */ + if (nr_online_nodes > 1 && cache_free_alien(cachep, objp)) + return; + + if (ac->avail < ac->limit) { + STATS_INC_FREEHIT(cachep); + } else { + STATS_INC_FREEMISS(cachep); + cache_flusharray(cachep, ac); + } + + if (sk_memalloc_socks()) { + struct page *page = virt_to_head_page(objp); + + if (unlikely(PageSlabPfmemalloc(page))) { + cache_free_pfmemalloc(cachep, page, objp); + return; + } + } + + __free_one(ac, objp); +} + +/** + * kmem_cache_alloc - Allocate an object + * @cachep: The cache to allocate from. + * @flags: See kmalloc(). + * + * Allocate an object from this cache. The flags are only relevant + * if the cache has no available objects. + * + * Return: pointer to the new object or %NULL in case of error + */ +void *kmem_cache_alloc(struct kmem_cache *cachep, gfp_t flags) +{ + void *ret = slab_alloc(cachep, flags, _RET_IP_); + + trace_kmem_cache_alloc(_RET_IP_, ret, + cachep->object_size, cachep->size, flags); + + return ret; +} +EXPORT_SYMBOL(kmem_cache_alloc); + +static __always_inline void +cache_alloc_debugcheck_after_bulk(struct kmem_cache *s, gfp_t flags, + size_t size, void **p, unsigned long caller) +{ + size_t i; + + for (i = 0; i < size; i++) + p[i] = cache_alloc_debugcheck_after(s, flags, p[i], caller); +} + +int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size, + void **p) +{ + size_t i; + struct obj_cgroup *objcg = NULL; + + s = slab_pre_alloc_hook(s, &objcg, size, flags); + if (!s) + return 0; + + cache_alloc_debugcheck_before(s, flags); + + local_irq_disable(); + for (i = 0; i < size; i++) { + void *objp = __do_cache_alloc(s, flags); + + if (unlikely(!objp)) + goto error; + p[i] = objp; + } + local_irq_enable(); + + cache_alloc_debugcheck_after_bulk(s, flags, size, p, _RET_IP_); + + /* Clear memory outside IRQ disabled section */ + if (unlikely(slab_want_init_on_alloc(flags, s))) + for (i = 0; i < size; i++) + memset(p[i], 0, s->object_size); + + slab_post_alloc_hook(s, objcg, flags, size, p); + /* FIXME: Trace call missing. Christoph would like a bulk variant */ + return size; +error: + local_irq_enable(); + cache_alloc_debugcheck_after_bulk(s, flags, i, p, _RET_IP_); + slab_post_alloc_hook(s, objcg, flags, i, p); + __kmem_cache_free_bulk(s, i, p); + return 0; +} +EXPORT_SYMBOL(kmem_cache_alloc_bulk); + +#ifdef CONFIG_TRACING +void * +kmem_cache_alloc_trace(struct kmem_cache *cachep, gfp_t flags, size_t size) +{ + void *ret; + + ret = slab_alloc(cachep, flags, _RET_IP_); + + ret = kasan_kmalloc(cachep, ret, size, flags); + trace_kmalloc(_RET_IP_, ret, + size, cachep->size, flags); + return ret; +} +EXPORT_SYMBOL(kmem_cache_alloc_trace); +#endif + +#ifdef CONFIG_NUMA +/** + * kmem_cache_alloc_node - Allocate an object on the specified node + * @cachep: The cache to allocate from. + * @flags: See kmalloc(). + * @nodeid: node number of the target node. + * + * Identical to kmem_cache_alloc but it will allocate memory on the given + * node, which can improve the performance for cpu bound structures. + * + * Fallback to other node is possible if __GFP_THISNODE is not set. + * + * Return: pointer to the new object or %NULL in case of error + */ +void *kmem_cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid) +{ + void *ret = slab_alloc_node(cachep, flags, nodeid, _RET_IP_); + + trace_kmem_cache_alloc_node(_RET_IP_, ret, + cachep->object_size, cachep->size, + flags, nodeid); + + return ret; +} +EXPORT_SYMBOL(kmem_cache_alloc_node); + +#ifdef CONFIG_TRACING +void *kmem_cache_alloc_node_trace(struct kmem_cache *cachep, + gfp_t flags, + int nodeid, + size_t size) +{ + void *ret; + + ret = slab_alloc_node(cachep, flags, nodeid, _RET_IP_); + + ret = kasan_kmalloc(cachep, ret, size, flags); + trace_kmalloc_node(_RET_IP_, ret, + size, cachep->size, + flags, nodeid); + return ret; +} +EXPORT_SYMBOL(kmem_cache_alloc_node_trace); +#endif + +static __always_inline void * +__do_kmalloc_node(size_t size, gfp_t flags, int node, unsigned long caller) +{ + struct kmem_cache *cachep; + void *ret; + + if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) + return NULL; + cachep = kmalloc_slab(size, flags); + if (unlikely(ZERO_OR_NULL_PTR(cachep))) + return cachep; + ret = kmem_cache_alloc_node_trace(cachep, flags, node, size); + ret = kasan_kmalloc(cachep, ret, size, flags); + + return ret; +} + +void *__kmalloc_node(size_t size, gfp_t flags, int node) +{ + return __do_kmalloc_node(size, flags, node, _RET_IP_); +} +EXPORT_SYMBOL(__kmalloc_node); + +void *__kmalloc_node_track_caller(size_t size, gfp_t flags, + int node, unsigned long caller) +{ + return __do_kmalloc_node(size, flags, node, caller); +} +EXPORT_SYMBOL(__kmalloc_node_track_caller); +#endif /* CONFIG_NUMA */ + +/** + * __do_kmalloc - allocate memory + * @size: how many bytes of memory are required. + * @flags: the type of memory to allocate (see kmalloc). + * @caller: function caller for debug tracking of the caller + * + * Return: pointer to the allocated memory or %NULL in case of error + */ +static __always_inline void *__do_kmalloc(size_t size, gfp_t flags, + unsigned long caller) +{ + struct kmem_cache *cachep; + void *ret; + + if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) + return NULL; + cachep = kmalloc_slab(size, flags); + if (unlikely(ZERO_OR_NULL_PTR(cachep))) + return cachep; + ret = slab_alloc(cachep, flags, caller); + + ret = kasan_kmalloc(cachep, ret, size, flags); + trace_kmalloc(caller, ret, + size, cachep->size, flags); + + return ret; +} + +void *__kmalloc(size_t size, gfp_t flags) +{ + return __do_kmalloc(size, flags, _RET_IP_); +} +EXPORT_SYMBOL(__kmalloc); + +void *__kmalloc_track_caller(size_t size, gfp_t flags, unsigned long caller) +{ + return __do_kmalloc(size, flags, caller); +} +EXPORT_SYMBOL(__kmalloc_track_caller); + +/** + * kmem_cache_free - Deallocate an object + * @cachep: The cache the allocation was from. + * @objp: The previously allocated object. + * + * Free an object which was previously allocated from this + * cache. + */ +void kmem_cache_free(struct kmem_cache *cachep, void *objp) +{ + unsigned long flags; + cachep = cache_from_obj(cachep, objp); + if (!cachep) + return; + + local_irq_save(flags); + debug_check_no_locks_freed(objp, cachep->object_size); + if (!(cachep->flags & SLAB_DEBUG_OBJECTS)) + debug_check_no_obj_freed(objp, cachep->object_size); + __cache_free(cachep, objp, _RET_IP_); + local_irq_restore(flags); + + trace_kmem_cache_free(_RET_IP_, objp); +} +EXPORT_SYMBOL(kmem_cache_free); + +void kmem_cache_free_bulk(struct kmem_cache *orig_s, size_t size, void **p) +{ + struct kmem_cache *s; + size_t i; + + local_irq_disable(); + for (i = 0; i < size; i++) { + void *objp = p[i]; + + if (!orig_s) /* called via kfree_bulk */ + s = virt_to_cache(objp); + else + s = cache_from_obj(orig_s, objp); + if (!s) + continue; + + debug_check_no_locks_freed(objp, s->object_size); + if (!(s->flags & SLAB_DEBUG_OBJECTS)) + debug_check_no_obj_freed(objp, s->object_size); + + __cache_free(s, objp, _RET_IP_); + } + local_irq_enable(); + + /* FIXME: add tracing */ +} +EXPORT_SYMBOL(kmem_cache_free_bulk); + +/** + * kfree - free previously allocated memory + * @objp: pointer returned by kmalloc. + * + * If @objp is NULL, no operation is performed. + * + * Don't free memory not originally allocated by kmalloc() + * or you will run into trouble. + */ +void kfree(const void *objp) +{ + struct kmem_cache *c; + unsigned long flags; + + trace_kfree(_RET_IP_, objp); + + if (unlikely(ZERO_OR_NULL_PTR(objp))) + return; + local_irq_save(flags); + kfree_debugcheck(objp); + c = virt_to_cache(objp); + if (!c) { + local_irq_restore(flags); + return; + } + debug_check_no_locks_freed(objp, c->object_size); + + debug_check_no_obj_freed(objp, c->object_size); + __cache_free(c, (void *)objp, _RET_IP_); + local_irq_restore(flags); +} +EXPORT_SYMBOL(kfree); + +/* + * This initializes kmem_cache_node or resizes various caches for all nodes. + */ +static int setup_kmem_cache_nodes(struct kmem_cache *cachep, gfp_t gfp) +{ + int ret; + int node; + struct kmem_cache_node *n; + + for_each_online_node(node) { + ret = setup_kmem_cache_node(cachep, node, gfp, true); + if (ret) + goto fail; + + } + + return 0; + +fail: + if (!cachep->list.next) { + /* Cache is not active yet. Roll back what we did */ + node--; + while (node >= 0) { + n = get_node(cachep, node); + if (n) { + kfree(n->shared); + free_alien_cache(n->alien); + kfree(n); + cachep->node[node] = NULL; + } + node--; + } + } + return -ENOMEM; +} + +/* Always called with the slab_mutex held */ +static int do_tune_cpucache(struct kmem_cache *cachep, int limit, + int batchcount, int shared, gfp_t gfp) +{ + struct array_cache __percpu *cpu_cache, *prev; + int cpu; + + cpu_cache = alloc_kmem_cache_cpus(cachep, limit, batchcount); + if (!cpu_cache) + return -ENOMEM; + + prev = cachep->cpu_cache; + cachep->cpu_cache = cpu_cache; + /* + * Without a previous cpu_cache there's no need to synchronize remote + * cpus, so skip the IPIs. + */ + if (prev) + kick_all_cpus_sync(); + + check_irq_on(); + cachep->batchcount = batchcount; + cachep->limit = limit; + cachep->shared = shared; + + if (!prev) + goto setup_node; + + for_each_online_cpu(cpu) { + LIST_HEAD(list); + int node; + struct kmem_cache_node *n; + struct array_cache *ac = per_cpu_ptr(prev, cpu); + + node = cpu_to_mem(cpu); + n = get_node(cachep, node); + spin_lock_irq(&n->list_lock); + free_block(cachep, ac->entry, ac->avail, node, &list); + spin_unlock_irq(&n->list_lock); + slabs_destroy(cachep, &list); + } + free_percpu(prev); + +setup_node: + return setup_kmem_cache_nodes(cachep, gfp); +} + +/* Called with slab_mutex held always */ +static int enable_cpucache(struct kmem_cache *cachep, gfp_t gfp) +{ + int err; + int limit = 0; + int shared = 0; + int batchcount = 0; + + err = cache_random_seq_create(cachep, cachep->num, gfp); + if (err) + goto end; + + if (limit && shared && batchcount) + goto skip_setup; + /* + * The head array serves three purposes: + * - create a LIFO ordering, i.e. return objects that are cache-warm + * - reduce the number of spinlock operations. + * - reduce the number of linked list operations on the slab and + * bufctl chains: array operations are cheaper. + * The numbers are guessed, we should auto-tune as described by + * Bonwick. + */ + if (cachep->size > 131072) + limit = 1; + else if (cachep->size > PAGE_SIZE) + limit = 8; + else if (cachep->size > 1024) + limit = 24; + else if (cachep->size > 256) + limit = 54; + else + limit = 120; + + /* + * CPU bound tasks (e.g. network routing) can exhibit cpu bound + * allocation behaviour: Most allocs on one cpu, most free operations + * on another cpu. For these cases, an efficient object passing between + * cpus is necessary. This is provided by a shared array. The array + * replaces Bonwick's magazine layer. + * On uniprocessor, it's functionally equivalent (but less efficient) + * to a larger limit. Thus disabled by default. + */ + shared = 0; + if (cachep->size <= PAGE_SIZE && num_possible_cpus() > 1) + shared = 8; + +#if DEBUG + /* + * With debugging enabled, large batchcount lead to excessively long + * periods with disabled local interrupts. Limit the batchcount + */ + if (limit > 32) + limit = 32; +#endif + batchcount = (limit + 1) / 2; +skip_setup: + err = do_tune_cpucache(cachep, limit, batchcount, shared, gfp); +end: + if (err) + pr_err("enable_cpucache failed for %s, error %d\n", + cachep->name, -err); + return err; +} + +/* + * Drain an array if it contains any elements taking the node lock only if + * necessary. Note that the node listlock also protects the array_cache + * if drain_array() is used on the shared array. + */ +static void drain_array(struct kmem_cache *cachep, struct kmem_cache_node *n, + struct array_cache *ac, int node) +{ + LIST_HEAD(list); + + /* ac from n->shared can be freed if we don't hold the slab_mutex. */ + check_mutex_acquired(); + + if (!ac || !ac->avail) + return; + + if (ac->touched) { + ac->touched = 0; + return; + } + + spin_lock_irq(&n->list_lock); + drain_array_locked(cachep, ac, node, false, &list); + spin_unlock_irq(&n->list_lock); + + slabs_destroy(cachep, &list); +} + +/** + * cache_reap - Reclaim memory from caches. + * @w: work descriptor + * + * Called from workqueue/eventd every few seconds. + * Purpose: + * - clear the per-cpu caches for this CPU. + * - return freeable pages to the main free memory pool. + * + * If we cannot acquire the cache chain mutex then just give up - we'll try + * again on the next iteration. + */ +static void cache_reap(struct work_struct *w) +{ + struct kmem_cache *searchp; + struct kmem_cache_node *n; + int node = numa_mem_id(); + struct delayed_work *work = to_delayed_work(w); + + if (!mutex_trylock(&slab_mutex)) + /* Give up. Setup the next iteration. */ + goto out; + + list_for_each_entry(searchp, &slab_caches, list) { + check_irq_on(); + + /* + * We only take the node lock if absolutely necessary and we + * have established with reasonable certainty that + * we can do some work if the lock was obtained. + */ + n = get_node(searchp, node); + + reap_alien(searchp, n); + + drain_array(searchp, n, cpu_cache_get(searchp), node); + + /* + * These are racy checks but it does not matter + * if we skip one check or scan twice. + */ + if (time_after(n->next_reap, jiffies)) + goto next; + + n->next_reap = jiffies + REAPTIMEOUT_NODE; + + drain_array(searchp, n, n->shared, node); + + if (n->free_touched) + n->free_touched = 0; + else { + int freed; + + freed = drain_freelist(searchp, n, (n->free_limit + + 5 * searchp->num - 1) / (5 * searchp->num)); + STATS_ADD_REAPED(searchp, freed); + } +next: + cond_resched(); + } + check_irq_on(); + mutex_unlock(&slab_mutex); + next_reap_node(); +out: + /* Set up the next iteration */ + schedule_delayed_work_on(smp_processor_id(), work, + round_jiffies_relative(REAPTIMEOUT_AC)); +} + +void get_slabinfo(struct kmem_cache *cachep, struct slabinfo *sinfo) +{ + unsigned long active_objs, num_objs, active_slabs; + unsigned long total_slabs = 0, free_objs = 0, shared_avail = 0; + unsigned long free_slabs = 0; + int node; + struct kmem_cache_node *n; + + for_each_kmem_cache_node(cachep, node, n) { + check_irq_on(); + spin_lock_irq(&n->list_lock); + + total_slabs += n->total_slabs; + free_slabs += n->free_slabs; + free_objs += n->free_objects; + + if (n->shared) + shared_avail += n->shared->avail; + + spin_unlock_irq(&n->list_lock); + } + num_objs = total_slabs * cachep->num; + active_slabs = total_slabs - free_slabs; + active_objs = num_objs - free_objs; + + sinfo->active_objs = active_objs; + sinfo->num_objs = num_objs; + sinfo->active_slabs = active_slabs; + sinfo->num_slabs = total_slabs; + sinfo->shared_avail = shared_avail; + sinfo->limit = cachep->limit; + sinfo->batchcount = cachep->batchcount; + sinfo->shared = cachep->shared; + sinfo->objects_per_slab = cachep->num; + sinfo->cache_order = cachep->gfporder; +} + +void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *cachep) +{ +#if STATS + { /* node stats */ + unsigned long high = cachep->high_mark; + unsigned long allocs = cachep->num_allocations; + unsigned long grown = cachep->grown; + unsigned long reaped = cachep->reaped; + unsigned long errors = cachep->errors; + unsigned long max_freeable = cachep->max_freeable; + unsigned long node_allocs = cachep->node_allocs; + unsigned long node_frees = cachep->node_frees; + unsigned long overflows = cachep->node_overflow; + + seq_printf(m, " : globalstat %7lu %6lu %5lu %4lu %4lu %4lu %4lu %4lu %4lu", + allocs, high, grown, + reaped, errors, max_freeable, node_allocs, + node_frees, overflows); + } + /* cpu stats */ + { + unsigned long allochit = atomic_read(&cachep->allochit); + unsigned long allocmiss = atomic_read(&cachep->allocmiss); + unsigned long freehit = atomic_read(&cachep->freehit); + unsigned long freemiss = atomic_read(&cachep->freemiss); + + seq_printf(m, " : cpustat %6lu %6lu %6lu %6lu", + allochit, allocmiss, freehit, freemiss); + } +#endif +} + +#define MAX_SLABINFO_WRITE 128 +/** + * slabinfo_write - Tuning for the slab allocator + * @file: unused + * @buffer: user buffer + * @count: data length + * @ppos: unused + * + * Return: %0 on success, negative error code otherwise. + */ +ssize_t slabinfo_write(struct file *file, const char __user *buffer, + size_t count, loff_t *ppos) +{ + char kbuf[MAX_SLABINFO_WRITE + 1], *tmp; + int limit, batchcount, shared, res; + struct kmem_cache *cachep; + + if (count > MAX_SLABINFO_WRITE) + return -EINVAL; + if (copy_from_user(&kbuf, buffer, count)) + return -EFAULT; + kbuf[MAX_SLABINFO_WRITE] = '\0'; + + tmp = strchr(kbuf, ' '); + if (!tmp) + return -EINVAL; + *tmp = '\0'; + tmp++; + if (sscanf(tmp, " %d %d %d", &limit, &batchcount, &shared) != 3) + return -EINVAL; + + /* Find the cache in the chain of caches. */ + mutex_lock(&slab_mutex); + res = -EINVAL; + list_for_each_entry(cachep, &slab_caches, list) { + if (!strcmp(cachep->name, kbuf)) { + if (limit < 1 || batchcount < 1 || + batchcount > limit || shared < 0) { + res = 0; + } else { + res = do_tune_cpucache(cachep, limit, + batchcount, shared, + GFP_KERNEL); + } + break; + } + } + mutex_unlock(&slab_mutex); + if (res >= 0) + res = count; + return res; +} + +#ifdef CONFIG_HARDENED_USERCOPY +/* + * Rejects incorrectly sized objects and objects that are to be copied + * to/from userspace but do not fall entirely within the containing slab + * cache's usercopy region. + * + * Returns NULL if check passes, otherwise const char * to name of cache + * to indicate an error. + */ +void __check_heap_object(const void *ptr, unsigned long n, struct page *page, + bool to_user) +{ + struct kmem_cache *cachep; + unsigned int objnr; + unsigned long offset; + + ptr = kasan_reset_tag(ptr); + + /* Find and validate object. */ + cachep = page->slab_cache; + objnr = obj_to_index(cachep, page, (void *)ptr); + BUG_ON(objnr >= cachep->num); + + /* Find offset within object. */ + offset = ptr - index_to_obj(cachep, page, objnr) - obj_offset(cachep); + + /* Allow address range falling entirely within usercopy region. */ + if (offset >= cachep->useroffset && + offset - cachep->useroffset <= cachep->usersize && + n <= cachep->useroffset - offset + cachep->usersize) + return; + + /* + * If the copy is still within the allocated object, produce + * a warning instead of rejecting the copy. This is intended + * to be a temporary method to find any missing usercopy + * whitelists. + */ + if (usercopy_fallback && + offset <= cachep->object_size && + n <= cachep->object_size - offset) { + usercopy_warn("SLAB object", cachep->name, to_user, offset, n); + return; + } + + usercopy_abort("SLAB object", cachep->name, to_user, offset, n); +} +#endif /* CONFIG_HARDENED_USERCOPY */ + +/** + * __ksize -- Uninstrumented ksize. + * @objp: pointer to the object + * + * Unlike ksize(), __ksize() is uninstrumented, and does not provide the same + * safety checks as ksize() with KASAN instrumentation enabled. + * + * Return: size of the actual memory used by @objp in bytes + */ +size_t __ksize(const void *objp) +{ + struct kmem_cache *c; + size_t size; + + BUG_ON(!objp); + if (unlikely(objp == ZERO_SIZE_PTR)) + return 0; + + c = virt_to_cache(objp); + size = c ? c->object_size : 0; + + return size; +} +EXPORT_SYMBOL(__ksize); |