--- /dev/null
+/*
+ * 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
projects / linux-drm-fsl-dcu.git / commitdiff