diff options
Diffstat (limited to 'mm/slub.c')
| -rw-r--r-- | mm/slub.c | 3144 |
1 files changed, 3144 insertions, 0 deletions
diff --git a/mm/slub.c b/mm/slub.c new file mode 100644 index 000000000000..0cd56bd74b64 --- /dev/null +++ b/mm/slub.c @@ -0,0 +1,3144 @@ +/* + * SLUB: A slab allocator that limits cache line use instead of queuing + * objects in per cpu and per node lists. + * + * The allocator synchronizes using per slab locks and only + * uses a centralized lock to manage a pool of partial slabs. + * + * (C) 2007 SGI, Christoph Lameter <clameter@sgi.com> + */ + +#include <linux/mm.h> +#include <linux/module.h> +#include <linux/bit_spinlock.h> +#include <linux/interrupt.h> +#include <linux/bitops.h> +#include <linux/slab.h> +#include <linux/seq_file.h> +#include <linux/cpu.h> +#include <linux/cpuset.h> +#include <linux/mempolicy.h> +#include <linux/ctype.h> +#include <linux/kallsyms.h> + +/* + * Lock order: + * 1. slab_lock(page) + * 2. slab->list_lock + * + * The slab_lock protects operations on the object of a particular + * slab and its metadata in the page struct. If the slab lock + * has been taken then no allocations nor frees can be performed + * on the objects in the slab nor can the slab be added or removed + * from the partial or full lists since this would mean modifying + * the page_struct of the slab. + * + * The list_lock protects the partial and full list on each node and + * the partial slab counter. If taken then no new slabs may be added or + * removed from the lists nor make the number of partial slabs be modified. + * (Note that the total number of slabs is an atomic value that may be + * modified without taking the list lock). + * + * The list_lock is a centralized lock and thus we avoid taking it as + * much as possible. As long as SLUB does not have to handle partial + * slabs, operations can continue without any centralized lock. F.e. + * allocating a long series of objects that fill up slabs does not require + * the list lock. + * + * The lock order is sometimes inverted when we are trying to get a slab + * off a list. We take the list_lock and then look for a page on the list + * to use. While we do that objects in the slabs may be freed. We can + * only operate on the slab if we have also taken the slab_lock. So we use + * a slab_trylock() on the slab. If trylock was successful then no frees + * can occur anymore and we can use the slab for allocations etc. If the + * slab_trylock() does not succeed then frees are in progress in the slab and + * we must stay away from it for a while since we may cause a bouncing + * cacheline if we try to acquire the lock. So go onto the next slab. + * If all pages are busy then we may allocate a new slab instead of reusing + * a partial slab. A new slab has noone operating on it and thus there is + * no danger of cacheline contention. + * + * Interrupts are disabled during allocation and deallocation in order to + * make the slab allocator safe to use in the context of an irq. In addition + * interrupts are disabled to ensure that the processor does not change + * while handling per_cpu slabs, due to kernel preemption. + * + * SLUB assigns one slab for allocation to each processor. + * Allocations only occur from these slabs called cpu slabs. + * + * Slabs with free elements are kept on a partial list. + * There is no list for full slabs. If an object in a full slab is + * freed then the slab will show up again on the partial lists. + * Otherwise there is no need to track full slabs unless we have to + * track full slabs for debugging purposes. + * + * Slabs are freed when they become empty. Teardown and setup is + * minimal so we rely on the page allocators per cpu caches for + * fast frees and allocs. + * + * Overloading of page flags that are otherwise used for LRU management. + * + * PageActive The slab is used as a cpu cache. Allocations + * may be performed from the slab. The slab is not + * on any slab list and cannot be moved onto one. + * + * PageError Slab requires special handling due to debug + * options set. This moves slab handling out of + * the fast path. + */ + +/* + * Issues still to be resolved: + * + * - The per cpu array is updated for each new slab and and is a remote + * cacheline for most nodes. This could become a bouncing cacheline given + * enough frequent updates. There are 16 pointers in a cacheline.so at + * max 16 cpus could compete. Likely okay. + * + * - Support PAGE_ALLOC_DEBUG. Should be easy to do. + * + * - Support DEBUG_SLAB_LEAK. Trouble is we do not know where the full + * slabs are in SLUB. + * + * - SLAB_DEBUG_INITIAL is not supported but I have never seen a use of + * it. + * + * - Variable sizing of the per node arrays + */ + +/* Enable to test recovery from slab corruption on boot */ +#undef SLUB_RESILIENCY_TEST + +#if PAGE_SHIFT <= 12 + +/* + * Small page size. Make sure that we do not fragment memory + */ +#define DEFAULT_MAX_ORDER 1 +#define DEFAULT_MIN_OBJECTS 4 + +#else + +/* + * Large page machines are customarily able to handle larger + * page orders. + */ +#define DEFAULT_MAX_ORDER 2 +#define DEFAULT_MIN_OBJECTS 8 + +#endif + +/* + * Flags from the regular SLAB that SLUB does not support: + */ +#define SLUB_UNIMPLEMENTED (SLAB_DEBUG_INITIAL) + +#define DEBUG_DEFAULT_FLAGS (SLAB_DEBUG_FREE | SLAB_RED_ZONE | \ + SLAB_POISON | SLAB_STORE_USER) +/* + * Set of flags that will prevent slab merging + */ +#define SLUB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \ + SLAB_TRACE | SLAB_DESTROY_BY_RCU) + +#define SLUB_MERGE_SAME (SLAB_DEBUG_FREE | SLAB_RECLAIM_ACCOUNT | \ + SLAB_CACHE_DMA) + +#ifndef ARCH_KMALLOC_MINALIGN +#define ARCH_KMALLOC_MINALIGN sizeof(void *) +#endif + +#ifndef ARCH_SLAB_MINALIGN +#define ARCH_SLAB_MINALIGN sizeof(void *) +#endif + +/* Internal SLUB flags */ +#define __OBJECT_POISON 0x80000000 /* Poison object */ + +static int kmem_size = sizeof(struct kmem_cache); + +#ifdef CONFIG_SMP +static struct notifier_block slab_notifier; +#endif + +static enum { + DOWN, /* No slab functionality available */ + PARTIAL, /* kmem_cache_open() works but kmalloc does not */ + UP, /* Everything works */ + SYSFS /* Sysfs up */ +} slab_state = DOWN; + +/* A list of all slab caches on the system */ +static DECLARE_RWSEM(slub_lock); +LIST_HEAD(slab_caches); + +#ifdef CONFIG_SYSFS +static int sysfs_slab_add(struct kmem_cache *); +static int sysfs_slab_alias(struct kmem_cache *, const char *); +static void sysfs_slab_remove(struct kmem_cache *); +#else +static int sysfs_slab_add(struct kmem_cache *s) { return 0; } +static int sysfs_slab_alias(struct kmem_cache *s, const char *p) { return 0; } +static void sysfs_slab_remove(struct kmem_cache *s) {} +#endif + +/******************************************************************** + * Core slab cache functions + *******************************************************************/ + +int slab_is_available(void) +{ + return slab_state >= UP; +} + +static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node) +{ +#ifdef CONFIG_NUMA + return s->node[node]; +#else + return &s->local_node; +#endif +} + +/* + * Object debugging + */ +static void print_section(char *text, u8 *addr, unsigned int length) +{ + int i, offset; + int newline = 1; + char ascii[17]; + + ascii[16] = 0; + + for (i = 0; i < length; i++) { + if (newline) { + printk(KERN_ERR "%10s 0x%p: ", text, addr + i); + newline = 0; + } + printk(" %02x", addr[i]); + offset = i % 16; + ascii[offset] = isgraph(addr[i]) ? addr[i] : '.'; + if (offset == 15) { + printk(" %s\n",ascii); + newline = 1; + } + } + if (!newline) { + i %= 16; + while (i < 16) { + printk(" "); + ascii[i] = ' '; + i++; + } + printk(" %s\n", ascii); + } +} + +/* + * Slow version of get and set free pointer. + * + * This requires touching the cache lines of kmem_cache. + * The offset can also be obtained from the page. In that + * case it is in the cacheline that we already need to touch. + */ +static void *get_freepointer(struct kmem_cache *s, void *object) +{ + return *(void **)(object + s->offset); +} + +static void set_freepointer(struct kmem_cache *s, void *object, void *fp) +{ + *(void **)(object + s->offset) = fp; +} + +/* + * Tracking user of a slab. + */ +struct track { + void *addr; /* Called from address */ + int cpu; /* Was running on cpu */ + int pid; /* Pid context */ + unsigned long when; /* When did the operation occur */ +}; + +enum track_item { TRACK_ALLOC, TRACK_FREE }; + +static struct track *get_track(struct kmem_cache *s, void *object, + enum track_item alloc) +{ + struct track *p; + + if (s->offset) + p = object + s->offset + sizeof(void *); + else + p = object + s->inuse; + + return p + alloc; +} + +static void set_track(struct kmem_cache *s, void *object, + enum track_item alloc, void *addr) +{ + struct track *p; + + if (s->offset) + p = object + s->offset + sizeof(void *); + else + p = object + s->inuse; + + p += alloc; + if (addr) { + p->addr = addr; + p->cpu = smp_processor_id(); + p->pid = current ? current->pid : -1; + p->when = jiffies; + } else + memset(p, 0, sizeof(struct track)); +} + +#define set_tracking(__s, __o, __a) set_track(__s, __o, __a, \ + __builtin_return_address(0)) + +static void init_tracking(struct kmem_cache *s, void *object) +{ + if (s->flags & SLAB_STORE_USER) { + set_track(s, object, TRACK_FREE, NULL); + set_track(s, object, TRACK_ALLOC, NULL); + } +} + +static void print_track(const char *s, struct track *t) +{ + if (!t->addr) + return; + + printk(KERN_ERR "%s: ", s); + __print_symbol("%s", (unsigned long)t->addr); + printk(" jiffies_ago=%lu cpu=%u pid=%d\n", jiffies - t->when, t->cpu, t->pid); +} + +static void print_trailer(struct kmem_cache *s, u8 *p) +{ + unsigned int off; /* Offset of last byte */ + + if (s->flags & SLAB_RED_ZONE) + print_section("Redzone", p + s->objsize, + s->inuse - s->objsize); + + printk(KERN_ERR "FreePointer 0x%p -> 0x%p\n", + p + s->offset, + get_freepointer(s, p)); + + if (s->offset) + off = s->offset + sizeof(void *); + else + off = s->inuse; + + if (s->flags & SLAB_STORE_USER) { + print_track("Last alloc", get_track(s, p, TRACK_ALLOC)); + print_track("Last free ", get_track(s, p, TRACK_FREE)); + off += 2 * sizeof(struct track); + } + + if (off != s->size) + /* Beginning of the filler is the free pointer */ + print_section("Filler", p + off, s->size - off); +} + +static void object_err(struct kmem_cache *s, struct page *page, + u8 *object, char *reason) +{ + u8 *addr = page_address(page); + + printk(KERN_ERR "*** SLUB %s: %s@0x%p slab 0x%p\n", + s->name, reason, object, page); + printk(KERN_ERR " offset=%tu flags=0x%04lx inuse=%u freelist=0x%p\n", + object - addr, page->flags, page->inuse, page->freelist); + if (object > addr + 16) + print_section("Bytes b4", object - 16, 16); + print_section("Object", object, min(s->objsize, 128)); + print_trailer(s, object); + dump_stack(); +} + +static void slab_err(struct kmem_cache *s, struct page *page, char *reason, ...) +{ + va_list args; + char buf[100]; + + va_start(args, reason); + vsnprintf(buf, sizeof(buf), reason, args); + va_end(args); + printk(KERN_ERR "*** SLUB %s: %s in slab @0x%p\n", s->name, buf, + page); + dump_stack(); +} + +static void init_object(struct kmem_cache *s, void *object, int active) +{ + u8 *p = object; + + if (s->flags & __OBJECT_POISON) { + memset(p, POISON_FREE, s->objsize - 1); + p[s->objsize -1] = POISON_END; + } + + if (s->flags & SLAB_RED_ZONE) + memset(p + s->objsize, + active ? SLUB_RED_ACTIVE : SLUB_RED_INACTIVE, + s->inuse - s->objsize); +} + +static int check_bytes(u8 *start, unsigned int value, unsigned int bytes) +{ + while (bytes) { + if (*start != (u8)value) + return 0; + start++; + bytes--; + } + return 1; +} + + +static int check_valid_pointer(struct kmem_cache *s, struct page *page, + void *object) +{ + void *base; + + if (!object) + return 1; + + base = page_address(page); + if (object < base || object >= base + s->objects * s->size || + (object - base) % s->size) { + return 0; + } + + return 1; +} + +/* + * Object layout: + * + * object address + * Bytes of the object to be managed. + * If the freepointer may overlay the object then the free + * pointer is the first word of the object. + * Poisoning uses 0x6b (POISON_FREE) and the last byte is + * 0xa5 (POISON_END) + * + * object + s->objsize + * Padding to reach word boundary. This is also used for Redzoning. + * Padding is extended to word size if Redzoning is enabled + * and objsize == inuse. + * We fill with 0xbb (RED_INACTIVE) for inactive objects and with + * 0xcc (RED_ACTIVE) for objects in use. + * + * object + s->inuse + * A. Free pointer (if we cannot overwrite object on free) + * B. Tracking data for SLAB_STORE_USER + * C. Padding to reach required alignment boundary + * Padding is done using 0x5a (POISON_INUSE) + * + * object + s->size + * + * If slabcaches are merged then the objsize and inuse boundaries are to + * be ignored. And therefore no slab options that rely on these boundaries + * may be used with merged slabcaches. + */ + +static void restore_bytes(struct kmem_cache *s, char *message, u8 data, + void *from, void *to) +{ + printk(KERN_ERR "@@@ SLUB: %s Restoring %s (0x%x) from 0x%p-0x%p\n", + s->name, message, data, from, to - 1); + memset(from, data, to - from); +} + +static int check_pad_bytes(struct kmem_cache *s, struct page *page, u8 *p) +{ + unsigned long off = s->inuse; /* The end of info */ + + if (s->offset) + /* Freepointer is placed after the object. */ + off += sizeof(void *); + + if (s->flags & SLAB_STORE_USER) + /* We also have user information there */ + off += 2 * sizeof(struct track); + + if (s->size == off) + return 1; + + if (check_bytes(p + off, POISON_INUSE, s->size - off)) + return 1; + + object_err(s, page, p, "Object padding check fails"); + + /* + * Restore padding + */ + restore_bytes(s, "object padding", POISON_INUSE, p + off, p + s->size); + return 0; +} + +static int slab_pad_check(struct kmem_cache *s, struct page *page) +{ + u8 *p; + int length, remainder; + + if (!(s->flags & SLAB_POISON)) + return 1; + + p = page_address(page); + length = s->objects * s->size; + remainder = (PAGE_SIZE << s->order) - length; + if (!remainder) + return 1; + + if (!check_bytes(p + length, POISON_INUSE, remainder)) { + printk(KERN_ERR "SLUB: %s slab 0x%p: Padding fails check\n", + s->name, p); + dump_stack(); + restore_bytes(s, "slab padding", POISON_INUSE, p + length, + p + length + remainder); + return 0; + } + return 1; +} + +static int check_object(struct kmem_cache *s, struct page *page, + void *object, int active) +{ + u8 *p = object; + u8 *endobject = object + s->objsize; + + if (s->flags & SLAB_RED_ZONE) { + unsigned int red = + active ? SLUB_RED_ACTIVE : SLUB_RED_INACTIVE; + + if (!check_bytes(endobject, red, s->inuse - s->objsize)) { + object_err(s, page, object, + active ? "Redzone Active" : "Redzone Inactive"); + restore_bytes(s, "redzone", red, + endobject, object + s->inuse); + return 0; + } + } else { + if ((s->flags & SLAB_POISON) && s->objsize < s->inuse && + !check_bytes(endobject, POISON_INUSE, + s->inuse - s->objsize)) { + object_err(s, page, p, "Alignment padding check fails"); + /* + * Fix it so that there will not be another report. + * + * Hmmm... We may be corrupting an object that now expects + * to be longer than allowed. + */ + restore_bytes(s, "alignment padding", POISON_INUSE, + endobject, object + s->inuse); + } + } + + if (s->flags & SLAB_POISON) { + if (!active && (s->flags & __OBJECT_POISON) && + (!check_bytes(p, POISON_FREE, s->objsize - 1) || + p[s->objsize - 1] != POISON_END)) { + + object_err(s, page, p, "Poison check failed"); + restore_bytes(s, "Poison", POISON_FREE, + p, p + s->objsize -1); + restore_bytes(s, "Poison", POISON_END, + p + s->objsize - 1, p + s->objsize); + return 0; + } + /* + * check_pad_bytes cleans up on its own. + */ + check_pad_bytes(s, page, p); + } + + if (!s->offset && active) + /* + * Object and freepointer overlap. Cannot check + * freepointer while object is allocated. + */ + return 1; + + /* Check free pointer validity */ + if (!check_valid_pointer(s, page, get_freepointer(s, p))) { + object_err(s, page, p, "Freepointer corrupt"); + /* + * No choice but to zap it and thus loose the remainder + * of the free objects in this slab. May cause + * another error because the object count maybe + * wrong now. + */ + set_freepointer(s, p, NULL); + return 0; + } + return 1; +} + +static int check_slab(struct kmem_cache *s, struct page *page) +{ + VM_BUG_ON(!irqs_disabled()); + + if (!PageSlab(page)) { + printk(KERN_ERR "SLUB: %s Not a valid slab page @0x%p " + "flags=%lx mapping=0x%p count=%d \n", + s->name, page, page->flags, page->mapping, + page_count(page)); + return 0; + } + if (page->offset * sizeof(void *) != s->offset) { + printk(KERN_ERR "SLUB: %s Corrupted offset %lu in slab @0x%p" + " flags=0x%lx mapping=0x%p count=%d\n", + s->name, + (unsigned long)(page->offset * sizeof(void *)), + page, + page->flags, + page->mapping, + page_count(page)); + dump_stack(); + return 0; + } + if (page->inuse > s->objects) { + printk(KERN_ERR "SLUB: %s Inuse %u > max %u in slab " + "page @0x%p flags=%lx mapping=0x%p count=%d\n", + s->name, page->inuse, s->objects, page, page->flags, + page->mapping, page_count(page)); + dump_stack(); + return 0; + } + /* Slab_pad_check fixes things up after itself */ + slab_pad_check(s, page); + return 1; +} + +/* + * Determine if a certain object on a page is on the freelist and + * therefore free. Must hold the slab lock for cpu slabs to + * guarantee that the chains are consistent. + */ +static int on_freelist(struct kmem_cache *s, struct page *page, void *search) +{ + int nr = 0; + void *fp = page->freelist; + void *object = NULL; + + while (fp && nr <= s->objects) { + if (fp == search) + return 1; + if (!check_valid_pointer(s, page, fp)) { + if (object) { + object_err(s, page, object, + "Freechain corrupt"); + set_freepointer(s, object, NULL); + break; + } else { + printk(KERN_ERR "SLUB: %s slab 0x%p " + "freepointer 0x%p corrupted.\n", + s->name, page, fp); + dump_stack(); + page->freelist = NULL; + page->inuse = s->objects; + return 0; + } + break; + } + object = fp; + fp = get_freepointer(s, object); + nr++; + } + + if (page->inuse != s->objects - nr) { + printk(KERN_ERR "slab %s: page 0x%p wrong object count." + " counter is %d but counted were %d\n", + s->name, page, page->inuse, + s->objects - nr); + page->inuse = s->objects - nr; + } + return search == NULL; +} + +static int alloc_object_checks(struct kmem_cache *s, struct page *page, + void *object) +{ + if (!check_slab(s, page)) + goto bad; + + if (object && !on_freelist(s, page, object)) { + printk(KERN_ERR "SLUB: %s Object 0x%p@0x%p " + "already allocated.\n", + s->name, object, page); + goto dump; + } + + if (!check_valid_pointer(s, page, object)) { + object_err(s, page, object, "Freelist Pointer check fails"); + goto dump; + } + + if (!object) + return 1; + + if (!check_object(s, page, object, 0)) + goto bad; + init_object(s, object, 1); + + if (s->flags & SLAB_TRACE) { + printk(KERN_INFO "TRACE %s alloc 0x%p inuse=%d fp=0x%p\n", + s->name, object, page->inuse, + page->freelist); + dump_stack(); + } + return 1; +dump: + dump_stack(); +bad: + if (PageSlab(page)) { + /* + * If this is a slab page then lets do the best we can + * to avoid issues in the future. Marking all objects + * as used avoids touching the remainder. + */ + printk(KERN_ERR "@@@ SLUB: %s slab 0x%p. Marking all objects used.\n", + s->name, page); + page->inuse = s->objects; + page->freelist = NULL; + /* Fix up fields that may be corrupted */ + page->offset = s->offset / sizeof(void *); + } + return 0; +} + +static int free_object_checks(struct kmem_cache *s, struct page *page, + void *object) +{ + if (!check_slab(s, page)) + goto fail; + + if (!check_valid_pointer(s, page, object)) { + printk(KERN_ERR "SLUB: %s slab 0x%p invalid " + "object pointer 0x%p\n", + s->name, page, object); + goto fail; + } + + if (on_freelist(s, page, object)) { + printk(KERN_ERR "SLUB: %s slab 0x%p object " + "0x%p already free.\n", s->name, page, object); + goto fail; + } + + if (!check_object(s, page, object, 1)) + return 0; + + if (unlikely(s != page->slab)) { + if (!PageSlab(page)) + printk(KERN_ERR "slab_free %s size %d: attempt to" + "free object(0x%p) outside of slab.\n", + s->name, s->size, object); + else + if (!page->slab) + printk(KERN_ERR + "slab_free : no slab(NULL) for object 0x%p.\n", + object); + else + printk(KERN_ERR "slab_free %s(%d): object at 0x%p" + " belongs to slab %s(%d)\n", + s->name, s->size, object, + page->slab->name, page->slab->size); + goto fail; + } + if (s->flags & SLAB_TRACE) { + printk(KERN_INFO "TRACE %s free 0x%p inuse=%d fp=0x%p\n", + s->name, object, page->inuse, + page->freelist); + print_section("Object", object, s->objsize); + dump_stack(); + } + init_object(s, object, 0); + return 1; +fail: + dump_stack(); + printk(KERN_ERR "@@@ SLUB: %s slab 0x%p object at 0x%p not freed.\n", + s->name, page, object); + return 0; +} + +/* + * Slab allocation and freeing + */ +static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node) +{ + struct page * page; + int pages = 1 << s->order; + + if (s->order) + flags |= __GFP_COMP; + + if (s->flags & SLAB_CACHE_DMA) + flags |= SLUB_DMA; + + if (node == -1) + page = alloc_pages(flags, s->order); + else + page = alloc_pages_node(node, flags, s->order); + + if (!page) + return NULL; + + mod_zone_page_state(page_zone(page), + (s->flags & SLAB_RECLAIM_ACCOUNT) ? + NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE, + pages); + + return page; +} + +static void setup_object(struct kmem_cache *s, struct page *page, + void *object) +{ + if (PageError(page)) { + init_object(s, object, 0); + init_tracking(s, object); + } + + if (unlikely(s->ctor)) { + int mode = SLAB_CTOR_CONSTRUCTOR; + + if (!(s->flags & __GFP_WAIT)) + mode |= SLAB_CTOR_ATOMIC; + + s->ctor(object, s, mode); + } +} + +static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node) +{ + struct page *page; + struct kmem_cache_node *n; + void *start; + void *end; + void *last; + void *p; + + if (flags & __GFP_NO_GROW) + return NULL; + + BUG_ON(flags & ~(GFP_DMA | GFP_LEVEL_MASK)); + + if (flags & __GFP_WAIT) + local_irq_enable(); + + page = allocate_slab(s, flags & GFP_LEVEL_MASK, node); + if (!page) + goto out; + + n = get_node(s, page_to_nid(page)); + if (n) + atomic_long_inc(&n->nr_slabs); + page->offset = s->offset / sizeof(void *); + page->slab = s; + page->flags |= 1 << PG_slab; + if (s->flags & (SLAB_DEBUG_FREE | SLAB_RED_ZONE | SLAB_POISON | + SLAB_STORE_USER | SLAB_TRACE)) + page->flags |= 1 << PG_error; + + start = page_address(page); + end = start + s->objects * s->size; + + if (unlikely(s->flags & SLAB_POISON)) + memset(start, POISON_INUSE, PAGE_SIZE << s->order); + + last = start; + for (p = start + s->size; p < end; p += s->size) { + setup_object(s, page, last); + set_freepointer(s, last, p); + last = p; + } + setup_object(s, page, last); + set_freepointer(s, last, NULL); + + page->freelist = start; + page->inuse = 0; +out: + if (flags & __GFP_WAIT) + local_irq_disable(); + return page; +} + +static void __free_slab(struct kmem_cache *s, struct page *page) +{ + int pages = 1 << s->order; + + if (unlikely(PageError(page) || s->dtor)) { + void *start = page_address(page); + void *end = start + (pages << PAGE_SHIFT); + void *p; + + slab_pad_check(s, page); + for (p = start; p <= end - s->size; p += s->size) { + if (s->dtor) + s->dtor(p, s, 0); + check_object(s, page, p, 0); + } + } + + mod_zone_page_state(page_zone(page), + (s->flags & SLAB_RECLAIM_ACCOUNT) ? + NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE, + - pages); + + page->mapping = NULL; + __free_pages(page, s->order); +} + +static void rcu_free_slab(struct rcu_head *h) +{ + struct page *page; + + page = container_of((struct list_head *)h, struct page, lru); + __free_slab(page->slab, page); +} + +static void free_slab(struct kmem_cache *s, struct page *page) +{ + if (unlikely(s->flags & SLAB_DESTROY_BY_RCU)) { + /* + * RCU free overloads the RCU head over the LRU + */ + struct rcu_head *head = (void *)&page->lru; + + call_rcu(head, rcu_free_slab); + } else + __free_slab(s, page); +} + +static void discard_slab(struct kmem_cache *s, struct page *page) +{ + struct kmem_cache_node *n = get_node(s, page_to_nid(page)); + + atomic_long_dec(&n->nr_slabs); + reset_page_mapcount(page); + page->flags &= ~(1 << PG_slab | 1 << PG_error); + free_slab(s, page); +} + +/* + * Per slab locking using the pagelock + */ +static __always_inline void slab_lock(struct page *page) +{ + bit_spin_lock(PG_locked, &page->flags); +} + +static __always_inline void slab_unlock(struct page *page) +{ + bit_spin_unlock(PG_locked, &page->flags); +} + +static __always_inline int slab_trylock(struct page *page) +{ + int rc = 1; + + rc = bit_spin_trylock(PG_locked, &page->flags); + return rc; +} + +/* + * Management of partially allocated slabs + */ +static void add_partial(struct kmem_cache *s, struct page *page) +{ + struct kmem_cache_node *n = get_node(s, page_to_nid(page)); + + spin_lock(&n->list_lock); + n->nr_partial++; + list_add(&page->lru, &n->partial); + spin_unlock(&n->list_lock); +} + +static void remove_partial(struct kmem_cache *s, + struct page *page) +{ + struct kmem_cache_node *n = get_node(s, page_to_nid(page)); + + spin_lock(&n->list_lock); + list_del(&page->lru); + n->nr_partial--; + spin_unlock(&n->list_lock); +} + +/* + * Lock page and remove it from the partial list + * + * Must hold list_lock + */ +static int lock_and_del_slab(struct kmem_cache_node *n, struct page *page) +{ + if (slab_trylock(page)) { + list_del(&page->lru); + n->nr_partial--; + return 1; + } + return 0; +} + +/* + * Try to get a partial slab from a specific node + */ +static struct page *get_partial_node(struct kmem_cache_node *n) +{ + struct page *page; + + /* + * Racy check. If we mistakenly see no partial slabs then we + * just allocate an empty slab. If we mistakenly try to get a + * partial slab then get_partials() will return NULL. + */ + if (!n || !n->nr_partial) + return NULL; + + spin_lock(&n->list_lock); + list_for_each_entry(page, &n->partial, lru) + if (lock_and_del_slab(n, page)) + goto out; + page = NULL; +out: + spin_unlock(&n->list_lock); + return page; +} + +/* + * Get a page from somewhere. Search in increasing NUMA + * distances. + */ +static struct page *get_any_partial(struct kmem_cache *s, gfp_t flags) +{ +#ifdef CONFIG_NUMA + struct zonelist *zonelist; + struct zone **z; + struct page *page; + + /* + * The defrag ratio allows to configure the tradeoffs between + * inter node defragmentation and node local allocations. + * A lower defrag_ratio increases the tendency to do local + * allocations instead of scanning throught the partial + * lists on other nodes. + * + * If defrag_ratio is set to 0 then kmalloc() always + * returns node local objects. If its higher then kmalloc() + * may return off node objects in order to avoid fragmentation. + * + * A higher ratio means slabs may be taken from other nodes + * thus reducing the number of partial slabs on those nodes. + * + * If /sys/slab/xx/defrag_ratio is set to 100 (which makes + * defrag_ratio = 1000) then every (well almost) allocation + * will first attempt to defrag slab caches on other nodes. This + * means scanning over all nodes to look for partial slabs which + * may be a bit expensive to do on every slab allocation. + */ + if (!s->defrag_ratio || get_cycles() % 1024 > s->defrag_ratio) + return NULL; + + zonelist = &NODE_DATA(slab_node(current->mempolicy)) + ->node_zonelists[gfp_zone(flags)]; + for (z = zonelist->zones; *z; z++) { + struct kmem_cache_node *n; + + n = get_node(s, zone_to_nid(*z)); + + if (n && cpuset_zone_allowed_hardwall(*z, flags) && + n->nr_partial > 2) { + page = get_partial_node(n); + if (page) + return page; + } + } +#endif + return NULL; +} + +/* + * Get a partial page, lock it and return it. + */ +static struct page *get_partial(struct kmem_cache *s, gfp_t flags, int node) +{ + struct page *page; + int searchnode = (node == -1) ? numa_node_id() : node; + + page = get_partial_node(get_node(s, searchnode)); + if (page || (flags & __GFP_THISNODE)) + return page; + + return get_any_partial(s, flags); +} + +/* + * Move a page back to the lists. + * + * Must be called with the slab lock held. + * + * On exit the slab lock will have been dropped. + */ +static void putback_slab(struct kmem_cache *s, struct page *page) +{ + if (page->inuse) { + if (page->freelist) + add_partial(s, page); + slab_unlock(page); + } else { + slab_unlock(page); + discard_slab(s, page); + } +} + +/* + * Remove the cpu slab + */ +static void deactivate_slab(struct kmem_cache *s, struct page *page, int cpu) +{ + s->cpu_slab[cpu] = NULL; + ClearPageActive(page); + + putback_slab(s, page); +} + +static void flush_slab(struct kmem_cache *s, struct page *page, int cpu) +{ + slab_lock(page); + deactivate_slab(s, page, cpu); +} + +/* + * Flush cpu slab. + * Called from IPI handler with interrupts disabled. + */ +static void __flush_cpu_slab(struct kmem_cache *s, int cpu) +{ + struct page *page = s->cpu_slab[cpu]; + + if (likely(page)) + flush_slab(s, page, cpu); +} + +static void flush_cpu_slab(void *d) +{ + struct kmem_cache *s = d; + int cpu = smp_processor_id(); + + __flush_cpu_slab(s, cpu); +} + +static void flush_all(struct kmem_cache *s) +{ +#ifdef CONFIG_SMP + on_each_cpu(flush_cpu_slab, s, 1, 1); +#else + unsigned long flags; + + local_irq_save(flags); + flush_cpu_slab(s); + local_irq_restore(flags); +#endif +} + +/* + * slab_alloc is optimized to only modify two cachelines on the fast path + * (aside from the stack): + * + * 1. The page struct + * 2. The first cacheline of the object to be allocated. + * + * The only cache lines that are read (apart from code) is the + * per cpu array in the kmem_cache struct. + * + * Fastpath is not possible if we need to get a new slab or have + * debugging enabled (which means all slabs are marked with PageError) + */ +static __always_inline void *slab_alloc(struct kmem_cache *s, + gfp_t gfpflags, int node) +{ + struct page *page; + void **object; + unsigned long flags; + int cpu; + + local_irq_save(flags); + cpu = smp_processor_id(); + page = s->cpu_slab[cpu]; + if (!page) + goto new_slab; + + slab_lock(page); + if (unlikely(node != -1 && page_to_nid(page) != node)) + goto another_slab; +redo: + object = page->freelist; + if (unlikely(!object)) + goto another_slab; + if (unlikely(PageError(page))) + goto debug; + +have_object: + page->inuse++; + page->freelist = object[page->offset]; + slab_unlock(page); + local_irq_restore(flags); + return object; + +another_slab: + deactivate_slab(s, page, cpu); + +new_slab: + page = get_partial(s, gfpflags, node); + if (likely(page)) { +have_slab: + s->cpu_slab[cpu] = page; + SetPageActive(page); + goto redo; + } + + page = new_slab(s, gfpflags, node); + if (page) { + cpu = smp_processor_id(); + if (s->cpu_slab[cpu]) { + /* + * Someone else populated the cpu_slab while we enabled + * interrupts, or we have got scheduled on another cpu. + * The page may not be on the requested node. + */ + if (node == -1 || + page_to_nid(s->cpu_slab[cpu]) == node) { + /* + * Current cpuslab is acceptable and we + * want the current one since its cache hot + */ + discard_slab(s, page); + page = s->cpu_slab[cpu]; + slab_lock(page); + goto redo; + } + /* Dump the current slab */ + flush_slab(s, s->cpu_slab[cpu], cpu); + } + slab_lock(page); + goto have_slab; + } + local_irq_restore(flags); + return NULL; +debug: + if (!alloc_object_checks(s, page, object)) + goto another_slab; + if (s->flags & SLAB_STORE_USER) + set_tracking(s, object, TRACK_ALLOC); + goto have_object; +} + +void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags) +{ + return slab_alloc(s, gfpflags, -1); +} +EXPORT_SYMBOL(kmem_cache_alloc); + +#ifdef CONFIG_NUMA +void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node) +{ + return slab_alloc(s, gfpflags, node); +} +EXPORT_SYMBOL(kmem_cache_alloc_node); +#endif + +/* + * The fastpath only writes the cacheline of the page struct and the first + * cacheline of the object. + * + * No special cachelines need to be read + */ +static void slab_free(struct kmem_cache *s, struct page *page, void *x) +{ + void *prior; + void **object = (void *)x; + unsigned long flags; + + local_irq_save(flags); + slab_lock(page); + + if (unlikely(PageError(page))) + goto debug; +checks_ok: + prior = object[page->offset] = page->freelist; + page->freelist = object; + page->inuse--; + + if (unlikely(PageActive(page))) + /* + * Cpu slabs are never on partial lists and are + * never freed. + */ + goto out_unlock; + + if (unlikely(!page->inuse)) + goto slab_empty; + + /* + * Objects left in the slab. If it + * was not on the partial list before + * then add it. + */ + if (unlikely(!prior)) + add_partial(s, page); + +out_unlock: + slab_unlock(page); + local_irq_restore(flags); + return; + +slab_empty: + if (prior) + /* + * Partially used slab that is on the partial list. + */ + remove_partial(s, page); + + slab_unlock(page); + discard_slab(s, page); + local_irq_restore(flags); + return; + +debug: + if (free_object_checks(s, page, x)) + goto checks_ok; + goto out_unlock; +} + +void kmem_cache_free(struct kmem_cache *s, void *x) +{ + struct page * page; + + page = virt_to_page(x); + + if (unlikely(PageCompound(page))) + page = page->first_page; + + + if (unlikely(PageError(page) && (s->flags & SLAB_STORE_USER))) + set_tracking(s, x, TRACK_FREE); + slab_free(s, page, x); +} +EXPORT_SYMBOL(kmem_cache_free); + +/* Figure out on which slab object the object resides */ +static struct page *get_object_page(const void *x) +{ + struct page *page = virt_to_page(x); + + if (unlikely(PageCompound(page))) + page = page->first_page; + + if (!PageSlab(page)) + return NULL; + + return page; +} + +/* + * kmem_cache_open produces objects aligned at "size" and the first object + * is placed at offset 0 in the slab (We have no metainformation on the + * slab, all slabs are in essence "off slab"). + * + * In order to get the desired alignment one just needs to align the + * size. + * + * Notice that the allocation order determines the sizes of the per cpu + * caches. Each processor has always one slab available for allocations. + * Increasing the allocation order reduces the number of times that slabs + * must be moved on and off the partial lists and therefore may influence + * locking overhead. + * + * The offset is used to relocate the free list link in each object. It is + * therefore possible to move the free list link behind the object. This + * is necessary for RCU to work properly and also useful for debugging. + */ + +/* + * Mininum / Maximum order of slab pages. This influences locking overhead + * and slab fragmentation. A higher order reduces the number of partial slabs + * and increases the number of allocations possible without having to + * take the list_lock. + */ +static int slub_min_order; +static int slub_max_order = DEFAULT_MAX_ORDER; + +/* + * Minimum number of objects per slab. This is necessary in order to + * reduce locking overhead. Similar to the queue size in SLAB. + */ +static int slub_min_objects = DEFAULT_MIN_OBJECTS; + +/* + * Merge control. If this is set then no merging of slab caches will occur. + */ +static int slub_nomerge; + +/* + * Debug settings: + */ +static int slub_debug; + +static char *slub_debug_slabs; + +/* + * Calculate the order of allocation given an slab object size. + * + * The order of allocation has significant impact on other elements + * of the system. Generally order 0 allocations should be preferred + * since they do not cause fragmentation in the page allocator. Larger + * objects may have problems with order 0 because there may be too much + * space left unused in a slab. We go to a higher order if more than 1/8th + * of the slab would be wasted. + * + * In order to reach satisfactory performance we must ensure that + * a minimum number of objects is in one slab. Otherwise we may + * generate too much activity on the partial lists. This is less a + * concern for large slabs though. slub_max_order specifies the order + * where we begin to stop considering the number of objects in a slab. + * + * Higher order allocations also allow the placement of more objects + * in a slab and thereby reduce object handling overhead. If the user + * has requested a higher mininum order then we start with that one + * instead of zero. + */ +static int calculate_order(int size) +{ + int order; + int rem; + + for (order = max(slub_min_order, fls(size - 1) - PAGE_SHIFT); + order < MAX_ORDER; order++) { + unsigned long slab_size = PAGE_SIZE << order; + + if (slub_max_order > order && + slab_size < slub_min_objects * size) + continue; + + if (slab_size < size) + continue; + + rem = slab_size % size; + + if (rem <= (PAGE_SIZE << order) / 8) + break; + + } + if (order >= MAX_ORDER) + return -E2BIG; + return order; +} + +/* + * Function to figure out which alignment to use from the + * various ways of specifying it. + */ +static unsigned long calculate_alignment(unsigned long flags, + unsigned long align, unsigned long size) +{ + /* + * If the user wants hardware cache aligned objects then + * follow that suggestion if the object is sufficiently + * large. + * + * The hardware cache alignment cannot override the + * specified alignment though. If that is greater + * then use it. + */ + if ((flags & (SLAB_MUST_HWCACHE_ALIGN | SLAB_HWCACHE_ALIGN)) && + size > L1_CACHE_BYTES / 2) + return max_t(unsigned long, align, L1_CACHE_BYTES); + + if (align < ARCH_SLAB_MINALIGN) + return ARCH_SLAB_MINALIGN; + + return ALIGN(align, sizeof(void *)); +} + +static void init_kmem_cache_node(struct kmem_cache_node *n) +{ + n->nr_partial = 0; + atomic_long_set(&n->nr_slabs, 0); + spin_lock_init(&n->list_lock); + INIT_LIST_HEAD(&n->partial); +} + +#ifdef CONFIG_NUMA +/* + * No kmalloc_node yet so do it by hand. We know that this is the first + * slab on the node for this slabcache. There are no concurrent accesses + * possible. + * + * Note that this function only works on the kmalloc_node_cache + * when allocating for the kmalloc_node_cache. + */ +static struct kmem_cache_node * __init early_kmem_cache_node_alloc(gfp_t gfpflags, + int node) +{ + struct page *page; + struct kmem_cache_node *n; + + BUG_ON(kmalloc_caches->size < sizeof(struct kmem_cache_node)); + + page = new_slab(kmalloc_caches, gfpflags | GFP_THISNODE, node); + /* new_slab() disables interupts */ + local_irq_enable(); + + BUG_ON(!page); + n = page->freelist; + BUG_ON(!n); + page->freelist = get_freepointer(kmalloc_caches, n); + page->inuse++; + kmalloc_caches->node[node] = n; + init_object(kmalloc_caches, n, 1); + init_kmem_cache_node(n); + atomic_long_inc(&n->nr_slabs); + add_partial(kmalloc_caches, page); + return n; +} + +static void free_kmem_cache_nodes(struct kmem_cache *s) +{ + int node; + + for_each_online_node(node) { + struct kmem_cache_node *n = s->node[node]; + if (n && n != &s->local_node) + kmem_cache_free(kmalloc_caches, n); + s->node[node] = NULL; + } +} + +static int init_kmem_cache_nodes(struct kmem_cache *s, gfp_t gfpflags) +{ + int node; + int local_node; + + if (slab_state >= UP) + local_node = page_to_nid(virt_to_page(s)); + else + local_node = 0; + + for_each_online_node(node) { + struct kmem_cache_node *n; + + if (local_node == node) + n = &s->local_node; + else { + if (slab_state == DOWN) { + n = early_kmem_cache_node_alloc(gfpflags, + node); + continue; + } + n = kmem_cache_alloc_node(kmalloc_caches, + gfpflags, node); + + if (!n) { + free_kmem_cache_nodes(s); + return 0; + } + + } + s->node[node] = n; + init_kmem_cache_node(n); + } + return 1; +} +#else +static void free_kmem_cache_nodes(struct kmem_cache *s) +{ +} + +static int init_kmem_cache_nodes(struct kmem_cache *s, gfp_t gfpflags) +{ + init_kmem_cache_node(&s->local_node); + return 1; +} +#endif + +/* + * calculate_sizes() determines the order and the distribution of data within + * a slab object. + */ +static int calculate_sizes(struct kmem_cache *s) +{ + unsigned long flags = s->flags; + unsigned long size = s->objsize; + unsigned long align = s->align; + + /* + * Determine if we can poison the object itself. If the user of + * the slab may touch the object after free or before allocation + * then we should never poison the object itself. + */ + if ((flags & SLAB_POISON) && !(flags & SLAB_DESTROY_BY_RCU) && + !s->ctor && !s->dtor) + s->flags |= __OBJECT_POISON; + else + s->flags &= ~__OBJECT_POISON; + + /* + * Round up object size to the next word boundary. We can only + * place the free pointer at word boundaries and this determines + * the possible location of the free pointer. + */ + size = ALIGN(size, sizeof(void *)); + + /* + * If we are redzoning then check if there is some space between the + * end of the object and the free pointer. If not then add an + * additional word, so that we can establish a redzone between + * the object and the freepointer to be able to check for overwrites. + */ + if ((flags & SLAB_RED_ZONE) && size == s->objsize) + size += sizeof(void *); + + /* + * With that we have determined how much of the slab is in actual + * use by the object. This is the potential offset to the free + * pointer. + */ + s->inuse = size; + + if (((flags & (SLAB_DESTROY_BY_RCU | SLAB_POISON)) || + s->ctor || s->dtor)) { + /* + * Relocate free pointer after the object if it is not + * permitted to overwrite the first word of the object on + * kmem_cache_free. + * + * This is the case if we do RCU, have a constructor or + * destructor or are poisoning the objects. + */ + s->offset = size; + size += sizeof(void *); + } + + if (flags & SLAB_STORE_USER) + /* + * Need to store information about allocs and frees after + * the object. + */ + size += 2 * sizeof(struct track); + + if (flags & DEBUG_DEFAULT_FLAGS) + /* + * Add some empty padding so that we can catch + * overwrites from earlier objects rather than let + * tracking information or the free pointer be + * corrupted if an user writes before the start + * of the object. + */ + size += sizeof(void *); + /* + * Determine the alignment based on various parameters that the + * user specified (this is unecessarily complex due to the attempt + * to be compatible with SLAB. Should be cleaned up some day). + */ + align = calculate_alignment(flags, align, s->objsize); + + /* + * SLUB stores one object immediately after another beginning from + * offset 0. In order to align the objects we have to simply size + * each object to conform to the alignment. + */ + size = ALIGN(size, align); + s->size = size; + + s->order = calculate_order(size); + if (s->order < 0) + return 0; + + /* + * Determine the number of objects per slab + */ + s->objects = (PAGE_SIZE << s->order) / size; + + /* + * Verify that the number of objects is within permitted limits. + * The page->inuse field is only 16 bit wide! So we cannot have + * more than 64k objects per slab. + */ + if (!s->objects || s->objects > 65535) + return 0; + return 1; + +} + +static int __init finish_bootstrap(void) +{ + struct list_head *h; + int err; + + slab_state = SYSFS; + + list_for_each(h, &slab_caches) { + struct kmem_cache *s = + container_of(h, struct kmem_cache, list); + + err = sysfs_slab_add(s); + BUG_ON(err); + } + return 0; +} + +static int kmem_cache_open(struct kmem_cache *s, gfp_t gfpflags, + const char *name, size_t size, + size_t align, unsigned long flags, + void (*ctor)(void *, struct kmem_cache *, unsigned long), + void (*dtor)(void *, struct kmem_cache *, unsigned long)) +{ + memset(s, 0, kmem_size); + s->name = name; + s->ctor = ctor; + s->dtor = dtor; + s->objsize = size; + s->flags = flags; + s->align = align; + + BUG_ON(flags & SLUB_UNIMPLEMENTED); + + /* + * The page->offset field is only 16 bit wide. This is an offset + * in units of words from the beginning of an object. If the slab + * size is bigger then we cannot move the free pointer behind the + * object anymore. + * + * On 32 bit platforms the limit is 256k. On 64bit platforms + * the limit is 512k. + * + * Debugging or ctor/dtors may create a need to move the free + * pointer. Fail if this happens. + */ + if (s->size >= 65535 * sizeof(void *)) { + BUG_ON(flags & (SLAB_RED_ZONE | SLAB_POISON | + SLAB_STORE_USER | SLAB_DESTROY_BY_RCU)); + BUG_ON(ctor || dtor); + } + else + /* + * Enable debugging if selected on the kernel commandline. + */ + if (slub_debug && (!slub_debug_slabs || + strncmp(slub_debug_slabs, name, + strlen(slub_debug_slabs)) == 0)) + s->flags |= slub_debug; + + if (!calculate_sizes(s)) + goto error; + + s->refcount = 1; +#ifdef CONFIG_NUMA + s->defrag_ratio = 100; +#endif + + if (init_kmem_cache_nodes(s, gfpflags & ~SLUB_DMA)) + return 1; +error: + if (flags & SLAB_PANIC) + panic("Cannot create slab %s size=%lu realsize=%u " + "order=%u offset=%u flags=%lx\n", + s->name, (unsigned long)size, s->size, s->order, + s->offset, flags); + return 0; +} +EXPORT_SYMBOL(kmem_cache_open); + +/* + * Check if a given pointer is valid + */ +int kmem_ptr_validate(struct kmem_cache *s, const void *object) +{ + struct page * page; + void *addr; + + page = get_object_page(object); + + if (!page || s != page->slab) + /* No slab or wrong slab */ + return 0; + + addr = page_address(page); + if (object < addr || object >= addr + s->objects * s->size) + /* Out of bounds */ + return 0; + + if ((object - addr) % s->size) + /* Improperly aligned */ + return 0; + + /* + * We could also check if the object is on the slabs freelist. + * But this would be too expensive and it seems that the main + * purpose of kmem_ptr_valid is to check if the object belongs + * to a certain slab. + */ + return 1; +} +EXPORT_SYMBOL(kmem_ptr_validate); + +/* + * Determine the size of a slab object + */ +unsigned int kmem_cache_size(struct kmem_cache *s) +{ + return s->objsize; +} +EXPORT_SYMBOL(kmem_cache_size); + +const char *kmem_cache_name(struct kmem_cache *s) +{ + return s->name; +} +EXPORT_SYMBOL(kmem_cache_name); + +/* + * Attempt to free all slabs on a node + */ +static int free_list(struct kmem_cache *s, struct kmem_cache_node *n, + struct list_head *list) +{ + int slabs_inuse = 0; + unsigned long flags; + struct page *page, *h; + + spin_lock_irqsave(&n->list_lock, flags); + list_for_each_entry_safe(page, h, list, lru) + if (!page->inuse) { + list_del(&page->lru); + discard_slab(s, page); + } else + slabs_inuse++; + spin_unlock_irqrestore(&n->list_lock, flags); + return slabs_inuse; +} + +/* + * Release all resources used by slab cache + */ +static int kmem_cache_close(struct kmem_cache *s) +{ + int node; + + flush_all(s); + + /* Attempt to free all objects */ + for_each_online_node(node) { + struct kmem_cache_node *n = get_node(s, node); + + free_list(s, n, &n->partial); + if (atomic_long_read(&n->nr_slabs)) + return 1; + } + free_kmem_cache_nodes(s); + return 0; +} + +/* + * Close a cache and release the kmem_cache structure + * (must be used for caches created using kmem_cache_create) + */ +void kmem_cache_destroy(struct kmem_cache *s) +{ + down_write(&slub_lock); + s->refcount--; + if (!s->refcount) { + list_del(&s->list); + if (kmem_cache_close(s)) + WARN_ON(1); + sysfs_slab_remove(s); + kfree(s); + } + up_write(&slub_lock); +} +EXPORT_SYMBOL(kmem_cache_destroy); + +/******************************************************************** + * Kmalloc subsystem + *******************************************************************/ + +struct kmem_cache kmalloc_caches[KMALLOC_SHIFT_HIGH + 1] __cacheline_aligned; +EXPORT_SYMBOL(kmalloc_caches); + +#ifdef CONFIG_ZONE_DMA +static struct kmem_cache *kmalloc_caches_dma[KMALLOC_SHIFT_HIGH + 1]; +#endif + +static int __init setup_slub_min_order(char *str) +{ + get_option (&str, &slub_min_order); + + return 1; +} + +__setup("slub_min_order=", setup_slub_min_order); + +static int __init setup_slub_max_order(char *str) +{ + get_option (&str, &slub_max_order); + + return 1; +} + +__setup("slub_max_order=", setup_slub_max_order); + +static int __init setup_slub_min_objects(char *str) +{ + get_option (&str, &slub_min_objects); + + return 1; +} + +__setup("slub_min_objects=", setup_slub_min_objects); + +static int __init setup_slub_nomerge(char *str) +{ + slub_nomerge = 1; + return 1; +} + +__setup("slub_nomerge", setup_slub_nomerge); + +static int __init setup_slub_debug(char *str) +{ + if (!str || *str != '=') + slub_debug = DEBUG_DEFAULT_FLAGS; + else { + str++; + if (*str == 0 || *str == ',') + slub_debug = DEBUG_DEFAULT_FLAGS; + else + for( ;*str && *str != ','; str++) + switch (*str) { + case 'f' : case 'F' : + slub_debug |= SLAB_DEBUG_FREE; + break; + case 'z' : case 'Z' : + slub_debug |= SLAB_RED_ZONE; + break; + case 'p' : case 'P' : + slub_debug |= SLAB_POISON; + break; + case 'u' : case 'U' : + slub_debug |= SLAB_STORE_USER; + break; + case 't' : case 'T' : + slub_debug |= SLAB_TRACE; + break; + default: + printk(KERN_ERR "slub_debug option '%c' " + "unknown. skipped\n",*str); + } + } + + if (*str == ',') + slub_debug_slabs = str + 1; + return 1; +} + +__setup("slub_debug", setup_slub_debug); + +static struct kmem_cache *create_kmalloc_cache(struct kmem_cache *s, + const char *name, int size, gfp_t gfp_flags) +{ + unsigned int flags = 0; + + if (gfp_flags & SLUB_DMA) + flags = SLAB_CACHE_DMA; + + down_write(&slub_lock); + if (!kmem_cache_open(s, gfp_flags, name, size, ARCH_KMALLOC_MINALIGN, + flags, NULL, NULL)) + goto panic; + + list_add(&s->list, &slab_caches); + up_write(&slub_lock); + if (sysfs_slab_add(s)) + goto panic; + return s; + +panic: + panic("Creation of kmalloc slab %s size=%d failed.\n", name, size); +} + +static struct kmem_cache *get_slab(size_t size, gfp_t flags) +{ + int index = kmalloc_index(size); + + if (!size) + return NULL; + + /* Allocation too large? */ + BUG_ON(index < 0); + +#ifdef CONFIG_ZONE_DMA + if ((flags & SLUB_DMA)) { + struct kmem_cache *s; + struct kmem_cache *x; + char *text; + size_t realsize; + + s = kmalloc_caches_dma[index]; + if (s) + return s; + + /* Dynamically create dma cache */ + x = kmalloc(kmem_size, flags & ~SLUB_DMA); + if (!x) + panic("Unable to allocate memory for dma cache\n"); + + if (index <= KMALLOC_SHIFT_HIGH) + realsize = 1 << index; + else { + if (index == 1) + realsize = 96; + else + realsize = 192; + } + + text = kasprintf(flags & ~SLUB_DMA, "kmalloc_dma-%d", + (unsigned int)realsize); + s = create_kmalloc_cache(x, text, realsize, flags); + kmalloc_caches_dma[index] = s; + return s; + } +#endif + return &kmalloc_caches[index]; +} + +void *__kmalloc(size_t size, gfp_t flags) +{ + struct kmem_cache *s = get_slab(size, flags); + + if (s) + return kmem_cache_alloc(s, flags); + return NULL; +} +EXPORT_SYMBOL(__kmalloc); + +#ifdef CONFIG_NUMA +void *__kmalloc_node(size_t size, gfp_t flags, int node) +{ + struct kmem_cache *s = get_slab(size, flags); + + if (s) + return kmem_cache_alloc_node(s, flags, node); + return NULL; +} +EXPORT_SYMBOL(__kmalloc_node); +#endif + +size_t ksize(const void *object) +{ + struct page *page = get_object_page(object); + struct kmem_cache *s; + + BUG_ON(!page); + s = page->slab; + BUG_ON(!s); + + /* + * Debugging requires use of the padding between object + * and whatever may come after it. + */ + if (s->flags & (SLAB_RED_ZONE | SLAB_POISON)) + return s->objsize; + + /* + * If we have the need to store the freelist pointer + * back there or track user information then we can + * only use the space before that information. + */ + if (s->flags & (SLAB_DESTROY_BY_RCU | SLAB_STORE_USER)) + return s->inuse; + + /* + * Else we can use all the padding etc for the allocation + */ + return s->size; +} +EXPORT_SYMBOL(ksize); + +void kfree(const void *x) +{ + struct kmem_cache *s; + struct page *page; + + if (!x) + return; + + page = virt_to_page(x); + + if (unlikely(PageCompound(page))) + page = page->first_page; + + s = page->slab; + + if (unlikely(PageError(page) && (s->flags & SLAB_STORE_USER))) + set_tracking(s, (void *)x, TRACK_FREE); + slab_free(s, page, (void *)x); +} +EXPORT_SYMBOL(kfree); + +/** + * krealloc - reallocate memory. The contents will remain unchanged. + * + * @p: object to reallocate memory for. + * @new_size: how many bytes of memory are required. + * @flags: the type of memory to allocate. + * + * The contents of the object pointed to are preserved up to the + * lesser of the new and old sizes. If @p is %NULL, krealloc() + * behaves exactly like kmalloc(). If @size is 0 and @p is not a + * %NULL pointer, the object pointed to is freed. + */ +void *krealloc(const void *p, size_t new_size, gfp_t flags) +{ + struct kmem_cache *new_cache; + void *ret; + struct page *page; + + if (unlikely(!p)) + return kmalloc(new_size, flags); + + if (unlikely(!new_size)) { + kfree(p); + return NULL; + } + + page = virt_to_page(p); + + if (unlikely(PageCompound(page))) + page = page->first_page; + + new_cache = get_slab(new_size, flags); + + /* + * If new size fits in the current cache, bail out. + */ + if (likely(page->slab == new_cache)) + return (void *)p; + + ret = kmalloc(new_size, flags); + if (ret) { + memcpy(ret, p, min(new_size, ksize(p))); + kfree(p); + } + return ret; +} +EXPORT_SYMBOL(krealloc); + +/******************************************************************** + * Basic setup of slabs + *******************************************************************/ + +void __init kmem_cache_init(void) +{ + int i; + +#ifdef CONFIG_NUMA + /* + * Must first have the slab cache available for the allocations of the + * struct kmalloc_cache_node's. There is special bootstrap code in + * kmem_cache_open for slab_state == DOWN. + */ + create_kmalloc_cache(&kmalloc_caches[0], "kmem_cache_node", + sizeof(struct kmem_cache_node), GFP_KERNEL); +#endif + + /* Able to allocate the per node structures */ + slab_state = PARTIAL; + + /* Caches that are not of the two-to-the-power-of size */ + create_kmalloc_cache(&kmalloc_caches[1], + "kmalloc-96", 96, GFP_KERNEL); + create_kmalloc_cache(&kmalloc_caches[2], + "kmalloc-192", 192, GFP_KERNEL); + + for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++) + create_kmalloc_cache(&kmalloc_caches[i], + "kmalloc", 1 << i, GFP_KERNEL); + + slab_state = UP; + + /* Provide the correct kmalloc names now that the caches are up */ + for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++) + kmalloc_caches[i]. name = + kasprintf(GFP_KERNEL, "kmalloc-%d", 1 << i); + +#ifdef CONFIG_SMP + register_cpu_notifier(&slab_notifier); +#endif + + if (nr_cpu_ids) /* Remove when nr_cpu_ids is fixed upstream ! */ + kmem_size = offsetof(struct kmem_cache, cpu_slab) + + nr_cpu_ids * sizeof(struct page *); + + printk(KERN_INFO "SLUB: Genslabs=%d, HWalign=%d, Order=%d-%d, MinObjects=%d," + " Processors=%d, Nodes=%d\n", + KMALLOC_SHIFT_HIGH, L1_CACHE_BYTES, + slub_min_order, slub_max_order, slub_min_objects, + nr_cpu_ids, nr_node_ids); +} + +/* + * Find a mergeable slab cache + */ +static int slab_unmergeable(struct kmem_cache *s) +{ + if (slub_nomerge || (s->flags & SLUB_NEVER_MERGE)) + return 1; + + if (s->ctor || s->dtor) + return 1; + + return 0; +} + +static struct kmem_cache *find_mergeable(size_t size, + size_t align, unsigned long flags, + void (*ctor)(void *, struct kmem_cache *, unsigned long), + void (*dtor)(void *, struct kmem_cache *, unsigned long)) +{ + struct list_head *h; + + if (slub_nomerge || (flags & SLUB_NEVER_MERGE)) + return NULL; + + if (ctor || dtor) + return NULL; + + size = ALIGN(size, sizeof(void *)); + align = calculate_alignment(flags, align, size); + size = ALIGN(size, align); + + list_for_each(h, &slab_caches) { + struct kmem_cache *s = + container_of(h, struct kmem_cache, list); + + if (slab_unmergeable(s)) + continue; + + if (size > s->size) + continue; + + if (((flags | slub_debug) & SLUB_MERGE_SAME) != + (s->flags & SLUB_MERGE_SAME)) + continue; + /* + * Check if alignment is compatible. + * Courtesy of Adrian Drzewiecki + */ + if ((s->size & ~(align -1)) != s->size) + continue; + + if (s->size - size >= sizeof(void *)) + continue; + + return s; + } + return NULL; +} + +struct kmem_cache *kmem_cache_create(const char *name, size_t size, + size_t align, unsigned long flags, + void (*ctor)(void *, struct kmem_cache *, unsigned long), + void (*dtor)(void *, struct kmem_cache *, unsigned long)) +{ + struct kmem_cache *s; + + down_write(&slub_lock); + s = find_mergeable(size, align, flags, dtor, ctor); + if (s) { + s->refcount++; + /* + * Adjust the object sizes so that we clear + * the complete object on kzalloc. + */ + s->objsize = max(s->objsize, (int)size); + s->inuse = max_t(int, s->inuse, ALIGN(size, sizeof(void *))); + if (sysfs_slab_alias(s, name)) + goto err; + } else { + s = kmalloc(kmem_size, GFP_KERNEL); + if (s && kmem_cache_open(s, GFP_KERNEL, name, + size, align, flags, ctor, dtor)) { + if (sysfs_slab_add(s)) { + kfree(s); + goto err; + } + list_add(&s->list, &slab_caches); + } else + kfree(s); + } + up_write(&slub_lock); + return s; + +err: + up_write(&slub_lock); + if (flags & SLAB_PANIC) + panic("Cannot create slabcache %s\n", name); + else + s = NULL; + return s; +} +EXPORT_SYMBOL(kmem_cache_create); + +void *kmem_cache_zalloc(struct kmem_cache *s, gfp_t flags) +{ + void *x; + + x = kmem_cache_alloc(s, flags); + if (x) + memset(x, 0, s->objsize); + return x; +} +EXPORT_SYMBOL(kmem_cache_zalloc); + +#ifdef CONFIG_SMP +static void for_all_slabs(void (*func)(struct kmem_cache *, int), int cpu) +{ + struct list_head *h; + + down_read(&slub_lock); + list_for_each(h, &slab_caches) { + struct kmem_cache *s = + container_of(h, struct kmem_cache, list); + + func(s, cpu); + } + up_read(&slub_lock); +} + +/* + * Use the cpu notifier to insure that the slab are flushed + * when necessary. + */ +static int __cpuinit slab_cpuup_callback(struct notifier_block *nfb, + unsigned long action, void *hcpu) +{ + long cpu = (long)hcpu; + + switch (action) { + case CPU_UP_CANCELED: + case CPU_DEAD: + for_all_slabs(__flush_cpu_slab, cpu); + break; + default: + break; + } + return NOTIFY_OK; +} + +static struct notifier_block __cpuinitdata slab_notifier = + { &slab_cpuup_callback, NULL, 0 }; + +#endif + +/*************************************************************** + * Compatiblility definitions + **************************************************************/ + +int kmem_cache_shrink(struct kmem_cache *s) +{ + flush_all(s); + return 0; +} +EXPORT_SYMBOL(kmem_cache_shrink); + +#ifdef CONFIG_NUMA + +/***************************************************************** + * Generic reaper used to support the page allocator + * (the cpu slabs are reaped by a per slab workqueue). + * + * Maybe move this to the page allocator? + ****************************************************************/ + +static DEFINE_PER_CPU(unsigned long, reap_node); + +static void init_reap_node(int cpu) +{ + int node; + + node = next_node(cpu_to_node(cpu), node_online_map); + if (node == MAX_NUMNODES) + node = first_node(node_online_map); + + __get_cpu_var(reap_node) = node; +} + +static void next_reap_node(void) +{ + int node = __get_cpu_var(reap_node); + + /* + * Also drain per cpu pages on remote zones + */ + if (node != numa_node_id()) + drain_node_pages(node); + + node = next_node(node, node_online_map); + if (unlikely(node >= MAX_NUMNODES)) + node = first_node(node_online_map); + __get_cpu_var(reap_node) = node; +} +#else +#define init_reap_node(cpu) do { } while (0) +#define next_reap_node(void) do { } while (0) +#endif + +#define REAPTIMEOUT_CPUC (2*HZ) + +#ifdef CONFIG_SMP +static DEFINE_PER_CPU(struct delayed_work, reap_work); + +static void cache_reap(struct work_struct *unused) +{ + next_reap_node(); + refresh_cpu_vm_stats(smp_processor_id()); + schedule_delayed_work(&__get_cpu_var(reap_work), + REAPTIMEOUT_CPUC); +} + +static void __devinit start_cpu_timer(int cpu) +{ + struct delayed_work *reap_work = &per_cpu(reap_work, cpu); + + /* + * When this gets called from do_initcalls via cpucache_init(), + * init_workqueues() has already run, so keventd will be setup + * at that time. + */ + if (keventd_up() && reap_work->work.func == NULL) { + init_reap_node(cpu); + INIT_DELAYED_WORK(reap_work, cache_reap); + schedule_delayed_work_on(cpu, reap_work, HZ + 3 * cpu); + } +} + +static int __init cpucache_init(void) +{ + int cpu; + + /* + * Register the timers that drain pcp pages and update vm statistics + */ + for_each_online_cpu(cpu) + start_cpu_timer(cpu); + return 0; +} +__initcall(cpucache_init); +#endif + +#ifdef SLUB_RESILIENCY_TEST +static unsigned long validate_slab_cache(struct kmem_cache *s); + +static void resiliency_test(void) +{ + u8 *p; + + printk(KERN_ERR "SLUB resiliency testing\n"); + printk(KERN_ERR "-----------------------\n"); + printk(KERN_ERR "A. Corruption after allocation\n"); + + p = kzalloc(16, GFP_KERNEL); + p[16] = 0x12; + printk(KERN_ERR "\n1. kmalloc-16: Clobber Redzone/next pointer" + " 0x12->0x%p\n\n", p + 16); + + validate_slab_cache(kmalloc_caches + 4); + + /* Hmmm... The next two are dangerous */ + p = kzalloc(32, GFP_KERNEL); + p[32 + sizeof(void *)] = 0x34; + printk(KERN_ERR "\n2. kmalloc-32: Clobber next pointer/next slab" + " 0x34 -> -0x%p\n", p); + printk(KERN_ERR "If allocated object is overwritten then not detectable\n\n"); + + validate_slab_cache(kmalloc_caches + 5); + p = kzalloc(64, GFP_KERNEL); + p += 64 + (get_cycles() & 0xff) * sizeof(void *); + *p = 0x56; + printk(KERN_ERR "\n3. kmalloc-64: corrupting random byte 0x56->0x%p\n", + p); + printk(KERN_ERR "If allocated object is overwritten then not detectable\n\n"); + validate_slab_cache(kmalloc_caches + 6); + + printk(KERN_ERR "\nB. Corruption after free\n"); + p = kzalloc(128, GFP_KERNEL); + kfree(p); + *p = 0x78; + printk(KERN_ERR "1. kmalloc-128: Clobber first word 0x78->0x%p\n\n", p); + validate_slab_cache(kmalloc_caches + 7); + + p = kzalloc(256, GFP_KERNEL); + kfree(p); + p[50] = 0x9a; + printk(KERN_ERR "\n2. kmalloc-256: Clobber 50th byte 0x9a->0x%p\n\n", p); + validate_slab_cache(kmalloc_caches + 8); + + p = kzalloc(512, GFP_KERNEL); + kfree(p); + p[512] = 0xab; + printk(KERN_ERR "\n3. kmalloc-512: Clobber redzone 0xab->0x%p\n\n", p); + validate_slab_cache(kmalloc_caches + 9); +} +#else +static void resiliency_test(void) {}; +#endif + +/* + * These are not as efficient as kmalloc for the non debug case. + * We do not have the page struct available so we have to touch one + * cacheline in struct kmem_cache to check slab flags. + */ +void *__kmalloc_track_caller(size_t size, gfp_t gfpflags, void *caller) +{ + struct kmem_cache *s = get_slab(size, gfpflags); + void *object; + + if (!s) + return NULL; + + object = kmem_cache_alloc(s, gfpflags); + + if (object && (s->flags & SLAB_STORE_USER)) + set_track(s, object, TRACK_ALLOC, caller); + + return object; +} + +void *__kmalloc_node_track_caller(size_t size, gfp_t gfpflags, + int node, void *caller) +{ + struct kmem_cache *s = get_slab(size, gfpflags); + void *object; + + if (!s) + return NULL; + + object = kmem_cache_alloc_node(s, gfpflags, node); + + if (object && (s->flags & SLAB_STORE_USER)) + set_track(s, object, TRACK_ALLOC, caller); + + return object; +} + +#ifdef CONFIG_SYSFS + +static unsigned long count_partial(struct kmem_cache_node *n) +{ + unsigned long flags; + unsigned long x = 0; + struct page *page; + + spin_lock_irqsave(&n->list_lock, flags); + list_for_each_entry(page, &n->partial, lru) + x += page->inuse; + spin_unlock_irqrestore(&n->list_lock, flags); + return x; +} + +enum slab_stat_type { + SL_FULL, + SL_PARTIAL, + SL_CPU, + SL_OBJECTS +}; + +#define SO_FULL (1 << SL_FULL) +#define SO_PARTIAL (1 << SL_PARTIAL) +#define SO_CPU (1 << SL_CPU) +#define SO_OBJECTS (1 << SL_OBJECTS) + +static unsigned long slab_objects(struct kmem_cache *s, + char *buf, unsigned long flags) +{ + unsigned long total = 0; + int cpu; + int node; + int x; + unsigned long *nodes; + unsigned long *per_cpu; + + nodes = kzalloc(2 * sizeof(unsigned long) * nr_node_ids, GFP_KERNEL); + per_cpu = nodes + nr_node_ids; + + for_each_possible_cpu(cpu) { + struct page *page = s->cpu_slab[cpu]; + int node; + + if (page) { + node = page_to_nid(page); + if (flags & SO_CPU) { + int x = 0; + + if (flags & SO_OBJECTS) + x = page->inuse; + else + x = 1; + total += x; + nodes[node] += x; + } + per_cpu[node]++; + } + } + + for_each_online_node(node) { + struct kmem_cache_node *n = get_node(s, node); + + if (flags & SO_PARTIAL) { + if (flags & SO_OBJECTS) + x = count_partial(n); + else + x = n->nr_partial; + total += x; + nodes[node] += x; + } + + if (flags & SO_FULL) { + int full_slabs = atomic_read(&n->nr_slabs) + - per_cpu[node] + - n->nr_partial; + + if (flags & SO_OBJECTS) + x = full_slabs * s->objects; + else + x = full_slabs; + total += x; + nodes[node] += x; + } + } + + x = sprintf(buf, "%lu", total); +#ifdef CONFIG_NUMA + for_each_online_node(node) + if (nodes[node]) + x += sprintf(buf + x, " N%d=%lu", + node, nodes[node]); +#endif + kfree(nodes); + return x + sprintf(buf + x, "\n"); +} + +static int any_slab_objects(struct kmem_cache *s) +{ + int node; + int cpu; + + for_each_possible_cpu(cpu) + if (s->cpu_slab[cpu]) + return 1; + + for_each_node(node) { + struct kmem_cache_node *n = get_node(s, node); + + if (n->nr_partial || atomic_read(&n->nr_slabs)) + return 1; + } + return 0; +} + +#define to_slab_attr(n) container_of(n, struct slab_attribute, attr) +#define to_slab(n) container_of(n, struct kmem_cache, kobj); + +struct slab_attribute { + struct attribute attr; + ssize_t (*show)(struct kmem_cache *s, char *buf); + ssize_t (*store)(struct kmem_cache *s, const char *x, size_t count); +}; + +#define SLAB_ATTR_RO(_name) \ + static struct slab_attribute _name##_attr = __ATTR_RO(_name) + +#define SLAB_ATTR(_name) \ + static struct slab_attribute _name##_attr = \ + __ATTR(_name, 0644, _name##_show, _name##_store) + + +static ssize_t slab_size_show(struct kmem_cache *s, char *buf) +{ + return sprintf(buf, "%d\n", s->size); +} +SLAB_ATTR_RO(slab_size); + +static ssize_t align_show(struct kmem_cache *s, char *buf) +{ + return sprintf(buf, "%d\n", s->align); +} +SLAB_ATTR_RO(align); + +static ssize_t object_size_show(struct kmem_cache *s, char *buf) +{ + return sprintf(buf, "%d\n", s->objsize); +} +SLAB_ATTR_RO(object_size); + +static ssize_t objs_per_slab_show(struct kmem_cache *s, char *buf) +{ + return sprintf(buf, "%d\n", s->objects); +} +SLAB_ATTR_RO(objs_per_slab); + +static ssize_t order_show(struct kmem_cache *s, char *buf) +{ + return sprintf(buf, "%d\n", s->order); +} +SLAB_ATTR_RO(order); + +static ssize_t ctor_show(struct kmem_cache *s, char *buf) +{ + if (s->ctor) { + int n = sprint_symbol(buf, (unsigned long)s->ctor); + + return n + sprintf(buf + n, "\n"); + } + return 0; +} +SLAB_ATTR_RO(ctor); + +static ssize_t dtor_show(struct kmem_cache *s, char *buf) +{ + if (s->dtor) { + int n = sprint_symbol(buf, (unsigned long)s->dtor); + + return n + sprintf(buf + n, "\n"); + } + return 0; +} +SLAB_ATTR_RO(dtor); + +static ssize_t aliases_show(struct kmem_cache *s, char *buf) +{ + return sprintf(buf, "%d\n", s->refcount - 1); +} +SLAB_ATTR_RO(aliases); + +static ssize_t slabs_show(struct kmem_cache *s, char *buf) +{ + return slab_objects(s, buf, SO_FULL|SO_PARTIAL|SO_CPU); +} +SLAB_ATTR_RO(slabs); + +static ssize_t partial_show(struct kmem_cache *s, char *buf) +{ + return slab_objects(s, buf, SO_PARTIAL); +} +SLAB_ATTR_RO(partial); + +static ssize_t cpu_slabs_show(struct kmem_cache *s, char *buf) +{ + return slab_objects(s, buf, SO_CPU); +} +SLAB_ATTR_RO(cpu_slabs); + +static ssize_t objects_show(struct kmem_cache *s, char *buf) +{ + return slab_objects(s, buf, SO_FULL|SO_PARTIAL|SO_CPU|SO_OBJECTS); +} +SLAB_ATTR_RO(objects); + +static ssize_t sanity_checks_show(struct kmem_cache *s, char *buf) +{ + return sprintf(buf, "%d\n", !!(s->flags & SLAB_DEBUG_FREE)); +} + +static ssize_t sanity_checks_store(struct kmem_cache *s, + const char *buf, size_t length) +{ + s->flags &= ~SLAB_DEBUG_FREE; + if (buf[0] == '1') + s->flags |= SLAB_DEBUG_FREE; + return length; +} +SLAB_ATTR(sanity_checks); + +static ssize_t trace_show(struct kmem_cache *s, char *buf) +{ + return sprintf(buf, "%d\n", !!(s->flags & SLAB_TRACE)); +} + +static ssize_t trace_store(struct kmem_cache *s, const char *buf, + size_t length) +{ + s->flags &= ~SLAB_TRACE; + if (buf[0] == '1') + s->flags |= SLAB_TRACE; + return length; +} +SLAB_ATTR(trace); + +static ssize_t reclaim_account_show(struct kmem_cache *s, char *buf) +{ + return sprintf(buf, "%d\n", !!(s->flags & SLAB_RECLAIM_ACCOUNT)); +} + +static ssize_t reclaim_account_store(struct kmem_cache *s, + const char *buf, size_t length) +{ + s->flags &= ~SLAB_RECLAIM_ACCOUNT; + if (buf[0] == '1') + s->flags |= SLAB_RECLAIM_ACCOUNT; + return length; +} +SLAB_ATTR(reclaim_account); + +static ssize_t hwcache_align_show(struct kmem_cache *s, char *buf) +{ + return sprintf(buf, "%d\n", !!(s->flags & + (SLAB_HWCACHE_ALIGN|SLAB_MUST_HWCACHE_ALIGN))); +} +SLAB_ATTR_RO(hwcache_align); + +#ifdef CONFIG_ZONE_DMA +static ssize_t cache_dma_show(struct kmem_cache *s, char *buf) +{ + return sprintf(buf, "%d\n", !!(s->flags & SLAB_CACHE_DMA)); +} +SLAB_ATTR_RO(cache_dma); +#endif + +static ssize_t destroy_by_rcu_show(struct kmem_cache *s, char *buf) +{ + return sprintf(buf, "%d\n", !!(s->flags & SLAB_DESTROY_BY_RCU)); +} +SLAB_ATTR_RO(destroy_by_rcu); + +static ssize_t red_zone_show(struct kmem_cache *s, char *buf) +{ + return sprintf(buf, "%d\n", !!(s->flags & SLAB_RED_ZONE)); +} + +static ssize_t red_zone_store(struct kmem_cache *s, + const char *buf, size_t length) +{ + if (any_slab_objects(s)) + return -EBUSY; + + s->flags &= ~SLAB_RED_ZONE; + if (buf[0] == '1') + s->flags |= SLAB_RED_ZONE; + calculate_sizes(s); + return length; +} +SLAB_ATTR(red_zone); + +static ssize_t poison_show(struct kmem_cache *s, char *buf) +{ + return sprintf(buf, "%d\n", !!(s->flags & SLAB_POISON)); +} + +static ssize_t poison_store(struct kmem_cache *s, + const char *buf, size_t length) +{ + if (any_slab_objects(s)) + return -EBUSY; + + s->flags &= ~SLAB_POISON; + if (buf[0] == '1') + s->flags |= SLAB_POISON; + calculate_sizes(s); + return length; +} +SLAB_ATTR(poison); + +static ssize_t store_user_show(struct kmem_cache *s, char *buf) +{ + return sprintf(buf, "%d\n", !!(s->flags & SLAB_STORE_USER)); +} + +static ssize_t store_user_store(struct kmem_cache *s, + const char *buf, size_t length) +{ + if (any_slab_objects(s)) + return -EBUSY; + + s->flags &= ~SLAB_STORE_USER; + if (buf[0] == '1') + s->flags |= SLAB_STORE_USER; + calculate_sizes(s); + return length; +} +SLAB_ATTR(store_user); + +#ifdef CONFIG_NUMA +static ssize_t defrag_ratio_show(struct kmem_cache *s, char *buf) +{ + return sprintf(buf, "%d\n", s->defrag_ratio / 10); +} + +static ssize_t defrag_ratio_store(struct kmem_cache *s, + const char *buf, size_t length) +{ + int n = simple_strtoul(buf, NULL, 10); + + if (n < 100) + s->defrag_ratio = n * 10; + return length; +} +SLAB_ATTR(defrag_ratio); +#endif + +static struct attribute * slab_attrs[] = { + &slab_size_attr.attr, + &object_size_attr.attr, + &objs_per_slab_attr.attr, + &order_attr.attr, + &objects_attr.attr, + &slabs_attr.attr, + &partial_attr.attr, + &cpu_slabs_attr.attr, + &ctor_attr.attr, + &dtor_attr.attr, + &aliases_attr.attr, + &align_attr.attr, + &sanity_checks_attr.attr, + &trace_attr.attr, + &hwcache_align_attr.attr, + &reclaim_account_attr.attr, + &destroy_by_rcu_attr.attr, + &red_zone_attr.attr, + &poison_attr.attr, + &store_user_attr.attr, +#ifdef CONFIG_ZONE_DMA + &cache_dma_attr.attr, +#endif +#ifdef CONFIG_NUMA + &defrag_ratio_attr.attr, +#endif + NULL +}; + +static struct attribute_group slab_attr_group = { + .attrs = slab_attrs, +}; + +static ssize_t slab_attr_show(struct kobject *kobj, + struct attribute *attr, + char *buf) +{ + struct slab_attribute *attribute; + struct kmem_cache *s; + int err; + + attribute = to_slab_attr(attr); + s = to_slab(kobj); + + if (!attribute->show) + return -EIO; + + err = attribute->show(s, buf); + + return err; +} + +static ssize_t slab_attr_store(struct kobject *kobj, + struct attribute *attr, + const char *buf, size_t len) +{ + struct slab_attribute *attribute; + struct kmem_cache *s; + int err; + + attribute = to_slab_attr(attr); + s = to_slab(kobj); + + if (!attribute->store) + return -EIO; + + err = attribute->store(s, buf, len); + + return err; +} + +static struct sysfs_ops slab_sysfs_ops = { + .show = slab_attr_show, + .store = slab_attr_store, +}; + +static struct kobj_type slab_ktype = { + .sysfs_ops = &slab_sysfs_ops, +}; + +static int uevent_filter(struct kset *kset, struct kobject *kobj) +{ + struct kobj_type *ktype = get_ktype(kobj); + + if (ktype == &slab_ktype) + return 1; + return 0; +} + +static struct kset_uevent_ops slab_uevent_ops = { + .filter = uevent_filter, +}; + +decl_subsys(slab, &slab_ktype, &slab_uevent_ops); + +#define ID_STR_LENGTH 64 + +/* Create a unique string id for a slab cache: + * format + * :[flags-]size:[memory address of kmemcache] + */ +static char *create_unique_id(struct kmem_cache *s) +{ + char *name = kmalloc(ID_STR_LENGTH, GFP_KERNEL); + char *p = name; + + BUG_ON(!name); + + *p++ = ':'; + /* + * First flags affecting slabcache operations. We will only + * get here for aliasable slabs so we do not need to support + * too many flags. The flags here must cover all flags that + * are matched during merging to guarantee that the id is + * unique. + */ + if (s->flags & SLAB_CACHE_DMA) + *p++ = 'd'; + if (s->flags & SLAB_RECLAIM_ACCOUNT) + *p++ = 'a'; + if (s->flags & SLAB_DEBUG_FREE) + *p++ = 'F'; + if (p != name + 1) + *p++ = '-'; + p += sprintf(p, "%07d", s->size); + BUG_ON(p > name + ID_STR_LENGTH - 1); + return name; +} + +static int sysfs_slab_add(struct kmem_cache *s) +{ + int err; + const char *name; + int unmergeable; + + if (slab_state < SYSFS) + /* Defer until later */ + return 0; + + unmergeable = slab_unmergeable(s); + if (unmergeable) { + /* + * Slabcache can never be merged so we can use the name proper. + * This is typically the case for debug situations. In that + * case we can catch duplicate names easily. + */ + sysfs_remove_link(&slab_subsys.kset.kobj, s->name); + name = s->name; + } else { + /* + * Create a unique name for the slab as a target + * for the symlinks. + */ + name = create_unique_id(s); + } + + kobj_set_kset_s(s, slab_subsys); + kobject_set_name(&s->kobj, name); + kobject_init(&s->kobj); + err = kobject_add(&s->kobj); + if (err) + return err; + + err = sysfs_create_group(&s->kobj, &slab_attr_group); + if (err) + return err; + kobject_uevent(&s->kobj, KOBJ_ADD); + if (!unmergeable) { + /* Setup first alias */ + sysfs_slab_alias(s, s->name); + kfree(name); + } + return 0; +} + +static void sysfs_slab_remove(struct kmem_cache *s) +{ + kobject_uevent(&s->kobj, KOBJ_REMOVE); + kobject_del(&s->kobj); +} + +/* + * Need to buffer aliases during bootup until sysfs becomes + * available lest we loose that information. + */ +struct saved_alias { + struct kmem_cache *s; + const char *name; + struct saved_alias *next; +}; + +struct saved_alias *alias_list; + +static int sysfs_slab_alias(struct kmem_cache *s, const char *name) +{ + struct saved_alias *al; + + if (slab_state == SYSFS) { + /* + * If we have a leftover link then remove it. + */ + sysfs_remove_link(&slab_subsys.kset.kobj, name); + return sysfs_create_link(&slab_subsys.kset.kobj, + &s->kobj, name); + } + + al = kmalloc(sizeof(struct saved_alias), GFP_KERNEL); + if (!al) + return -ENOMEM; + + al->s = s; + al->name = name; + al->next = alias_list; + alias_list = al; + return 0; +} + +static int __init slab_sysfs_init(void) +{ + int err; + + err = subsystem_register(&slab_subsys); + if (err) { + printk(KERN_ERR "Cannot register slab subsystem.\n"); + return -ENOSYS; + } + + finish_bootstrap(); + + while (alias_list) { + struct saved_alias *al = alias_list; + + alias_list = alias_list->next; + err = sysfs_slab_alias(al->s, al->name); + BUG_ON(err); + kfree(al); + } + + resiliency_test(); + return 0; +} + +__initcall(slab_sysfs_init); +#else +__initcall(finish_bootstrap); +#endif |