--- /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 or atomic operatios
+ * and only uses a centralized lock to manage a pool of partial slabs.
+ *
+ * (C) 2007 SGI, Christoph Lameter
+ * (C) 2011 Linux Foundation, Christoph Lameter
+ */
+
+#include <linux/mm.h>
+#include <linux/swap.h> /* struct reclaim_state */
+#include <linux/module.h>
+#include <linux/bit_spinlock.h>
+#include <linux/interrupt.h>
+#include <linux/bitops.h>
+#include <linux/slab.h>
+#include "slab.h"
+#include <linux/proc_fs.h>
+#include <linux/notifier.h>
+#include <linux/seq_file.h>
+#include <linux/kasan.h>
+#include <linux/kmemcheck.h>
+#include <linux/cpu.h>
+#include <linux/cpuset.h>
+#include <linux/mempolicy.h>
+#include <linux/ctype.h>
+#include <linux/debugobjects.h>
+#include <linux/kallsyms.h>
+#include <linux/memory.h>
+#include <linux/math64.h>
+#include <linux/fault-inject.h>
+#include <linux/stacktrace.h>
+#include <linux/prefetch.h>
+#include <linux/memcontrol.h>
+
+#include <trace/events/kmem.h>
+
+#include "internal.h"
+
+/*
+ * Lock order:
+ * 1. slab_mutex (Global Mutex)
+ * 2. node->list_lock
+ * 3. slab_lock(page) (Only on some arches and for debugging)
+ *
+ * slab_mutex
+ *
+ * The role of the slab_mutex is to protect the list of all the slabs
+ * and to synchronize major metadata changes to slab cache structures.
+ *
+ * The slab_lock is only used for debugging and on arches that do not
+ * have the ability to do a cmpxchg_double. It only protects the second
+ * double word in the page struct. Meaning
+ * A. page->freelist -> List of object free in a page
+ * B. page->counters -> Counters of objects
+ * C. page->frozen -> frozen state
+ *
+ * If a slab is frozen then it is exempt from list management. It is not
+ * on any list. The processor that froze the slab is the one who can
+ * perform list operations on the page. Other processors may put objects
+ * onto the freelist but the processor that froze the slab is the only
+ * one that can retrieve the objects from the page's freelist.
+ *
+ * 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.
+ * 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 and during regular
+ * operations no list for full slabs is used. If an object in a full slab is
+ * freed then the slab will show up again on the partial lists.
+ * We track full slabs for debugging purposes though because otherwise we
+ * cannot scan all objects.
+ *
+ * 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 frozen and exempt from list processing.
+ * This means that the slab is dedicated to a purpose
+ * such as satisfying allocations for a specific
+ * processor. Objects may be freed in the slab while
+ * it is frozen but slab_free will then skip the usual
+ * list operations. It is up to the processor holding
+ * the slab to integrate the slab into the slab lists
+ * when the slab is no longer needed.
+ *
+ * One use of this flag is to mark slabs that are
+ * used for allocations. Then such a slab becomes a cpu
+ * slab. The cpu slab may be equipped with an additional
+ * freelist that allows lockless access to
+ * free objects in addition to the regular freelist
+ * that requires the slab lock.
+ *
+ * PageError Slab requires special handling due to debug
+ * options set. This moves slab handling out of
+ * the fast path and disables lockless freelists.
+ */
+
+static inline int kmem_cache_debug(struct kmem_cache *s)
+{
+#ifdef CONFIG_SLUB_DEBUG
+ return unlikely(s->flags & SLAB_DEBUG_FLAGS);
+#else
+ return 0;
+#endif
+}
+
+static inline bool kmem_cache_has_cpu_partial(struct kmem_cache *s)
+{
+#ifdef CONFIG_SLUB_CPU_PARTIAL
+ return !kmem_cache_debug(s);
+#else
+ return false;
+#endif
+}
+
+/*
+ * Issues still to be resolved:
+ *
+ * - Support PAGE_ALLOC_DEBUG. Should be easy to do.
+ *
+ * - Variable sizing of the per node arrays
+ */
+
+/* Enable to test recovery from slab corruption on boot */
+#undef SLUB_RESILIENCY_TEST
+
+/* Enable to log cmpxchg failures */
+#undef SLUB_DEBUG_CMPXCHG
+
+/*
+ * Mininum number of partial slabs. These will be left on the partial
+ * lists even if they are empty. kmem_cache_shrink may reclaim them.
+ */
+#define MIN_PARTIAL 5
+
+/*
+ * Maximum number of desirable partial slabs.
+ * The existence of more partial slabs makes kmem_cache_shrink
+ * sort the partial list by the number of objects in use.
+ */
+#define MAX_PARTIAL 10
+
+#define DEBUG_DEFAULT_FLAGS (SLAB_DEBUG_FREE | SLAB_RED_ZONE | \
+ SLAB_POISON | SLAB_STORE_USER)
+
+/*
+ * Debugging flags that require metadata to be stored in the slab. These get
+ * disabled when slub_debug=O is used and a cache's min order increases with
+ * metadata.
+ */
+#define DEBUG_METADATA_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
+
+#define OO_SHIFT 16
+#define OO_MASK ((1 << OO_SHIFT) - 1)
+#define MAX_OBJS_PER_PAGE 32767 /* since page.objects is u15 */
+
+/* Internal SLUB flags */
+#define __OBJECT_POISON 0x80000000UL /* Poison object */
+#define __CMPXCHG_DOUBLE 0x40000000UL /* Use cmpxchg_double */
+
+#ifdef CONFIG_SMP
+static struct notifier_block slab_notifier;
+#endif
+
+/*
+ * Tracking user of a slab.
+ */
+#define TRACK_ADDRS_COUNT 16
+struct track {
+ unsigned long addr; /* Called from address */
+#ifdef CONFIG_STACKTRACE
+ unsigned long addrs[TRACK_ADDRS_COUNT]; /* Called from address */
+#endif
+ 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 };
+
+#ifdef CONFIG_SYSFS
+static int sysfs_slab_add(struct kmem_cache *);
+static int sysfs_slab_alias(struct kmem_cache *, const char *);
+static void memcg_propagate_slab_attrs(struct kmem_cache *s);
+#else
+static inline int sysfs_slab_add(struct kmem_cache *s) { return 0; }
+static inline int sysfs_slab_alias(struct kmem_cache *s, const char *p)
+ { return 0; }
+static inline void memcg_propagate_slab_attrs(struct kmem_cache *s) { }
+#endif
+
+static inline void stat(const struct kmem_cache *s, enum stat_item si)
+{
+#ifdef CONFIG_SLUB_STATS
+ /*
+ * The rmw is racy on a preemptible kernel but this is acceptable, so
+ * avoid this_cpu_add()'s irq-disable overhead.
+ */
+ raw_cpu_inc(s->cpu_slab->stat[si]);
+#endif
+}
+
+/********************************************************************
+ * Core slab cache functions
+ *******************************************************************/
+
+/* Verify that a pointer has an address that is valid within a slab page */
+static inline int check_valid_pointer(struct kmem_cache *s,
+ struct page *page, const void *object)
+{
+ void *base;
+
+ if (!object)
+ return 1;
+
+ base = page_address(page);
+ if (object < base || object >= base + page->objects * s->size ||
+ (object - base) % s->size) {
+ return 0;
+ }
+
+ return 1;
+}
+
+static inline void *get_freepointer(struct kmem_cache *s, void *object)
+{
+ return *(void **)(object + s->offset);
+}
+
+static void prefetch_freepointer(const struct kmem_cache *s, void *object)
+{
+ prefetch(object + s->offset);
+}
+
+static inline void *get_freepointer_safe(struct kmem_cache *s, void *object)
+{
+ void *p;
+
+#ifdef CONFIG_DEBUG_PAGEALLOC
+ probe_kernel_read(&p, (void **)(object + s->offset), sizeof(p));
+#else
+ p = get_freepointer(s, object);
+#endif
+ return p;
+}
+
+static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp)
+{
+ *(void **)(object + s->offset) = fp;
+}
+
+/* Loop over all objects in a slab */
+#define for_each_object(__p, __s, __addr, __objects) \
+ for (__p = (__addr); __p < (__addr) + (__objects) * (__s)->size;\
+ __p += (__s)->size)
+
+#define for_each_object_idx(__p, __idx, __s, __addr, __objects) \
+ for (__p = (__addr), __idx = 1; __idx <= __objects;\
+ __p += (__s)->size, __idx++)
+
+/* Determine object index from a given position */
+static inline int slab_index(void *p, struct kmem_cache *s, void *addr)
+{
+ return (p - addr) / s->size;
+}
+
+static inline size_t slab_ksize(const struct kmem_cache *s)
+{
+#ifdef CONFIG_SLUB_DEBUG
+ /*
+ * Debugging requires use of the padding between object
+ * and whatever may come after it.
+ */
+ if (s->flags & (SLAB_RED_ZONE | SLAB_POISON))
+ return s->object_size;
+
+#endif
+ /*
+ * 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;
+}
+
+static inline int order_objects(int order, unsigned long size, int reserved)
+{
+ return ((PAGE_SIZE << order) - reserved) / size;
+}
+
+static inline struct kmem_cache_order_objects oo_make(int order,
+ unsigned long size, int reserved)
+{
+ struct kmem_cache_order_objects x = {
+ (order << OO_SHIFT) + order_objects(order, size, reserved)
+ };
+
+ return x;
+}
+
+static inline int oo_order(struct kmem_cache_order_objects x)
+{
+ return x.x >> OO_SHIFT;
+}
+
+static inline int oo_objects(struct kmem_cache_order_objects x)
+{
+ return x.x & OO_MASK;
+}
+
+/*
+ * 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 inline void set_page_slub_counters(struct page *page, unsigned long counters_new)
+{
+ struct page tmp;
+ tmp.counters = counters_new;
+ /*
+ * page->counters can cover frozen/inuse/objects as well
+ * as page->_count. If we assign to ->counters directly
+ * we run the risk of losing updates to page->_count, so
+ * be careful and only assign to the fields we need.
+ */
+ page->frozen = tmp.frozen;
+ page->inuse = tmp.inuse;
+ page->objects = tmp.objects;
+}
+
+/* Interrupts must be disabled (for the fallback code to work right) */
+static inline bool __cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
+ void *freelist_old, unsigned long counters_old,
+ void *freelist_new, unsigned long counters_new,
+ const char *n)
+{
+ VM_BUG_ON(!irqs_disabled());
+#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
+ defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
+ if (s->flags & __CMPXCHG_DOUBLE) {
+ if (cmpxchg_double(&page->freelist, &page->counters,
+ freelist_old, counters_old,
+ freelist_new, counters_new))
+ return true;
+ } else
+#endif
+ {
+ slab_lock(page);
+ if (page->freelist == freelist_old &&
+ page->counters == counters_old) {
+ page->freelist = freelist_new;
+ set_page_slub_counters(page, counters_new);
+ slab_unlock(page);
+ return true;
+ }
+ slab_unlock(page);
+ }
+
+ cpu_relax();
+ stat(s, CMPXCHG_DOUBLE_FAIL);
+
+#ifdef SLUB_DEBUG_CMPXCHG
+ pr_info("%s %s: cmpxchg double redo ", n, s->name);
+#endif
+
+ return false;
+}
+
+static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
+ void *freelist_old, unsigned long counters_old,
+ void *freelist_new, unsigned long counters_new,
+ const char *n)
+{
+#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
+ defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
+ if (s->flags & __CMPXCHG_DOUBLE) {
+ if (cmpxchg_double(&page->freelist, &page->counters,
+ freelist_old, counters_old,
+ freelist_new, counters_new))
+ return true;
+ } else
+#endif
+ {
+ unsigned long flags;
+
+ local_irq_save(flags);
+ slab_lock(page);
+ if (page->freelist == freelist_old &&
+ page->counters == counters_old) {
+ page->freelist = freelist_new;
+ set_page_slub_counters(page, counters_new);
+ slab_unlock(page);
+ local_irq_restore(flags);
+ return true;
+ }
+ slab_unlock(page);
+ local_irq_restore(flags);
+ }
+
+ cpu_relax();
+ stat(s, CMPXCHG_DOUBLE_FAIL);
+
+#ifdef SLUB_DEBUG_CMPXCHG
+ pr_info("%s %s: cmpxchg double redo ", n, s->name);
+#endif
+
+ return false;
+}
+
+#ifdef CONFIG_SLUB_DEBUG
+/*
+ * Determine a map of object in use on a page.
+ *
+ * Node listlock must be held to guarantee that the page does
+ * not vanish from under us.
+ */
+static void get_map(struct kmem_cache *s, struct page *page, unsigned long *map)
+{
+ void *p;
+ void *addr = page_address(page);
+
+ for (p = page->freelist; p; p = get_freepointer(s, p))
+ set_bit(slab_index(p, s, addr), map);
+}
+
+/*
+ * Debug settings:
+ */
+#ifdef CONFIG_SLUB_DEBUG_ON
+static int slub_debug = DEBUG_DEFAULT_FLAGS;
+#else
+static int slub_debug;
+#endif
+
+static char *slub_debug_slabs;
+static int disable_higher_order_debug;
+
+/*
+ * slub is about to manipulate internal object metadata. This memory lies
+ * outside the range of the allocated object, so accessing it would normally
+ * be reported by kasan as a bounds error. metadata_access_enable() is used
+ * to tell kasan that these accesses are OK.
+ */
+static inline void metadata_access_enable(void)
+{
+ kasan_disable_current();
+}
+
+static inline void metadata_access_disable(void)
+{
+ kasan_enable_current();
+}
+
+/*
+ * Object debugging
+ */
+static void print_section(char *text, u8 *addr, unsigned int length)
+{
+ metadata_access_enable();
+ print_hex_dump(KERN_ERR, text, DUMP_PREFIX_ADDRESS, 16, 1, addr,
+ length, 1);
+ metadata_access_disable();
+}
+
+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, unsigned long addr)
+{
+ struct track *p = get_track(s, object, alloc);
+
+ if (addr) {
+#ifdef CONFIG_STACKTRACE
+ struct stack_trace trace;
+ int i;
+
+ trace.nr_entries = 0;
+ trace.max_entries = TRACK_ADDRS_COUNT;
+ trace.entries = p->addrs;
+ trace.skip = 3;
+ metadata_access_enable();
+ save_stack_trace(&trace);
+ metadata_access_disable();
+
+ /* See rant in lockdep.c */
+ if (trace.nr_entries != 0 &&
+ trace.entries[trace.nr_entries - 1] == ULONG_MAX)
+ trace.nr_entries--;
+
+ for (i = trace.nr_entries; i < TRACK_ADDRS_COUNT; i++)
+ p->addrs[i] = 0;
+#endif
+ p->addr = addr;
+ p->cpu = smp_processor_id();
+ p->pid = current->pid;
+ p->when = jiffies;
+ } else
+ memset(p, 0, sizeof(struct track));
+}
+
+static void init_tracking(struct kmem_cache *s, void *object)
+{
+ if (!(s->flags & SLAB_STORE_USER))
+ return;
+
+ set_track(s, object, TRACK_FREE, 0UL);
+ set_track(s, object, TRACK_ALLOC, 0UL);
+}
+
+static void print_track(const char *s, struct track *t)
+{
+ if (!t->addr)
+ return;
+
+ pr_err("INFO: %s in %pS age=%lu cpu=%u pid=%d\n",
+ s, (void *)t->addr, jiffies - t->when, t->cpu, t->pid);
+#ifdef CONFIG_STACKTRACE
+ {
+ int i;
+ for (i = 0; i < TRACK_ADDRS_COUNT; i++)
+ if (t->addrs[i])
+ pr_err("\t%pS\n", (void *)t->addrs[i]);
+ else
+ break;
+ }
+#endif
+}
+
+static void print_tracking(struct kmem_cache *s, void *object)
+{
+ if (!(s->flags & SLAB_STORE_USER))
+ return;
+
+ print_track("Allocated", get_track(s, object, TRACK_ALLOC));
+ print_track("Freed", get_track(s, object, TRACK_FREE));
+}
+
+static void print_page_info(struct page *page)
+{
+ pr_err("INFO: Slab 0x%p objects=%u used=%u fp=0x%p flags=0x%04lx\n",
+ page, page->objects, page->inuse, page->freelist, page->flags);
+
+}
+
+static void slab_bug(struct kmem_cache *s, char *fmt, ...)
+{
+ struct va_format vaf;
+ va_list args;
+
+ va_start(args, fmt);
+ vaf.fmt = fmt;
+ vaf.va = &args;
+ pr_err("=============================================================================\n");
+ pr_err("BUG %s (%s): %pV\n", s->name, print_tainted(), &vaf);
+ pr_err("-----------------------------------------------------------------------------\n\n");
+
+ add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
+ va_end(args);
+}
+
+static void slab_fix(struct kmem_cache *s, char *fmt, ...)
+{
+ struct va_format vaf;
+ va_list args;
+
+ va_start(args, fmt);
+ vaf.fmt = fmt;
+ vaf.va = &args;
+ pr_err("FIX %s: %pV\n", s->name, &vaf);
+ va_end(args);
+}
+
+static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p)
+{
+ unsigned int off; /* Offset of last byte */
+ u8 *addr = page_address(page);
+
+ print_tracking(s, p);
+
+ print_page_info(page);
+
+ pr_err("INFO: Object 0x%p @offset=%tu fp=0x%p\n\n",
+ p, p - addr, get_freepointer(s, p));
+
+ if (p > addr + 16)
+ print_section("Bytes b4 ", p - 16, 16);
+
+ print_section("Object ", p, min_t(unsigned long, s->object_size,
+ PAGE_SIZE));
+ if (s->flags & SLAB_RED_ZONE)
+ print_section("Redzone ", p + s->object_size,
+ s->inuse - s->object_size);
+
+ if (s->offset)
+ off = s->offset + sizeof(void *);
+ else
+ off = s->inuse;
+
+ if (s->flags & SLAB_STORE_USER)
+ off += 2 * sizeof(struct track);
+
+ if (off != s->size)
+ /* Beginning of the filler is the free pointer */
+ print_section("Padding ", p + off, s->size - off);
+
+ dump_stack();
+}
+
+void object_err(struct kmem_cache *s, struct page *page,
+ u8 *object, char *reason)
+{
+ slab_bug(s, "%s", reason);
+ print_trailer(s, page, object);
+}
+
+static void slab_err(struct kmem_cache *s, struct page *page,
+ const char *fmt, ...)
+{
+ va_list args;
+ char buf[100];
+
+ va_start(args, fmt);
+ vsnprintf(buf, sizeof(buf), fmt, args);
+ va_end(args);
+ slab_bug(s, "%s", buf);
+ print_page_info(page);
+ dump_stack();
+}
+
+static void init_object(struct kmem_cache *s, void *object, u8 val)
+{
+ u8 *p = object;
+
+ if (s->flags & __OBJECT_POISON) {
+ memset(p, POISON_FREE, s->object_size - 1);
+ p[s->object_size - 1] = POISON_END;
+ }
+
+ if (s->flags & SLAB_RED_ZONE)
+ memset(p + s->object_size, val, s->inuse - s->object_size);
+}
+
+static void restore_bytes(struct kmem_cache *s, char *message, u8 data,
+ void *from, void *to)
+{
+ slab_fix(s, "Restoring 0x%p-0x%p=0x%x\n", from, to - 1, data);
+ memset(from, data, to - from);
+}
+
+static int check_bytes_and_report(struct kmem_cache *s, struct page *page,
+ u8 *object, char *what,
+ u8 *start, unsigned int value, unsigned int bytes)
+{
+ u8 *fault;
+ u8 *end;
+
+ metadata_access_enable();
+ fault = memchr_inv(start, value, bytes);
+ metadata_access_disable();
+ if (!fault)
+ return 1;
+
+ end = start + bytes;
+ while (end > fault && end[-1] == value)
+ end--;
+
+ slab_bug(s, "%s overwritten", what);
+ pr_err("INFO: 0x%p-0x%p. First byte 0x%x instead of 0x%x\n",
+ fault, end - 1, fault[0], value);
+ print_trailer(s, page, object);
+
+ restore_bytes(s, what, value, fault, end);
+ return 0;
+}
+
+/*
+ * 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->object_size
+ * Padding to reach word boundary. This is also used for Redzoning.
+ * Padding is extended by another word if Redzoning is enabled and
+ * object_size == inuse.
+ *
+ * We fill with 0xbb (RED_INACTIVE) for inactive objects and with
+ * 0xcc (RED_ACTIVE) for objects in use.
+ *
+ * object + s->inuse
+ * Meta data starts here.
+ *
+ * A. Free pointer (if we cannot overwrite object on free)
+ * B. Tracking data for SLAB_STORE_USER
+ * C. Padding to reach required alignment boundary or at mininum
+ * one word if debugging is on to be able to detect writes
+ * before the word boundary.
+ *
+ * Padding is done using 0x5a (POISON_INUSE)
+ *
+ * object + s->size
+ * Nothing is used beyond s->size.
+ *
+ * If slabcaches are merged then the object_size and inuse boundaries are mostly
+ * ignored. And therefore no slab options that rely on these boundaries
+ * may be used with merged slabcaches.
+ */
+
+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;
+
+ return check_bytes_and_report(s, page, p, "Object padding",
+ p + off, POISON_INUSE, s->size - off);
+}
+
+/* Check the pad bytes at the end of a slab page */
+static int slab_pad_check(struct kmem_cache *s, struct page *page)
+{
+ u8 *start;
+ u8 *fault;
+ u8 *end;
+ int length;
+ int remainder;
+
+ if (!(s->flags & SLAB_POISON))
+ return 1;
+
+ start = page_address(page);
+ length = (PAGE_SIZE << compound_order(page)) - s->reserved;
+ end = start + length;
+ remainder = length % s->size;
+ if (!remainder)
+ return 1;
+
+ metadata_access_enable();
+ fault = memchr_inv(end - remainder, POISON_INUSE, remainder);
+ metadata_access_disable();
+ if (!fault)
+ return 1;
+ while (end > fault && end[-1] == POISON_INUSE)
+ end--;
+
+ slab_err(s, page, "Padding overwritten. 0x%p-0x%p", fault, end - 1);
+ print_section("Padding ", end - remainder, remainder);
+
+ restore_bytes(s, "slab padding", POISON_INUSE, end - remainder, end);
+ return 0;
+}
+
+static int check_object(struct kmem_cache *s, struct page *page,
+ void *object, u8 val)
+{
+ u8 *p = object;
+ u8 *endobject = object + s->object_size;
+
+ if (s->flags & SLAB_RED_ZONE) {
+ if (!check_bytes_and_report(s, page, object, "Redzone",
+ endobject, val, s->inuse - s->object_size))
+ return 0;
+ } else {
+ if ((s->flags & SLAB_POISON) && s->object_size < s->inuse) {
+ check_bytes_and_report(s, page, p, "Alignment padding",
+ endobject, POISON_INUSE,
+ s->inuse - s->object_size);
+ }
+ }
+
+ if (s->flags & SLAB_POISON) {
+ if (val != SLUB_RED_ACTIVE && (s->flags & __OBJECT_POISON) &&
+ (!check_bytes_and_report(s, page, p, "Poison", p,
+ POISON_FREE, s->object_size - 1) ||
+ !check_bytes_and_report(s, page, p, "Poison",
+ p + s->object_size - 1, POISON_END, 1)))
+ return 0;
+ /*
+ * check_pad_bytes cleans up on its own.
+ */
+ check_pad_bytes(s, page, p);
+ }
+
+ if (!s->offset && val == SLUB_RED_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 lose the remainder
+ * of the free objects in this slab. May cause
+ * another error because the object count is now wrong.
+ */
+ set_freepointer(s, p, NULL);
+ return 0;
+ }
+ return 1;
+}
+
+static int check_slab(struct kmem_cache *s, struct page *page)
+{
+ int maxobj;
+
+ VM_BUG_ON(!irqs_disabled());
+
+ if (!PageSlab(page)) {
+ slab_err(s, page, "Not a valid slab page");
+ return 0;
+ }
+
+ maxobj = order_objects(compound_order(page), s->size, s->reserved);
+ if (page->objects > maxobj) {
+ slab_err(s, page, "objects %u > max %u",
+ page->objects, maxobj);
+ return 0;
+ }
+ if (page->inuse > page->objects) {
+ slab_err(s, page, "inuse %u > max %u",
+ page->inuse, page->objects);
+ 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. Must hold the
+ * slab lock to guarantee that the chains are in a consistent state.
+ */
+static int on_freelist(struct kmem_cache *s, struct page *page, void *search)
+{
+ int nr = 0;
+ void *fp;
+ void *object = NULL;
+ int max_objects;
+
+ fp = page->freelist;
+ while (fp && nr <= page->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);
+ } else {
+ slab_err(s, page, "Freepointer corrupt");
+ page->freelist = NULL;
+ page->inuse = page->objects;
+ slab_fix(s, "Freelist cleared");
+ return 0;
+ }
+ break;
+ }
+ object = fp;
+ fp = get_freepointer(s, object);
+ nr++;
+ }
+
+ max_objects = order_objects(compound_order(page), s->size, s->reserved);
+ if (max_objects > MAX_OBJS_PER_PAGE)
+ max_objects = MAX_OBJS_PER_PAGE;
+
+ if (page->objects != max_objects) {
+ slab_err(s, page, "Wrong number of objects. Found %d but "
+ "should be %d", page->objects, max_objects);
+ page->objects = max_objects;
+ slab_fix(s, "Number of objects adjusted.");
+ }
+ if (page->inuse != page->objects - nr) {
+ slab_err(s, page, "Wrong object count. Counter is %d but "
+ "counted were %d", page->inuse, page->objects - nr);
+ page->inuse = page->objects - nr;
+ slab_fix(s, "Object count adjusted.");
+ }
+ return search == NULL;
+}
+
+static void trace(struct kmem_cache *s, struct page *page, void *object,
+ int alloc)
+{
+ if (s->flags & SLAB_TRACE) {
+ pr_info("TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
+ s->name,
+ alloc ? "alloc" : "free",
+ object, page->inuse,
+ page->freelist);
+
+ if (!alloc)
+ print_section("Object ", (void *)object,
+ s->object_size);
+
+ dump_stack();
+ }
+}
+
+/*
+ * Tracking of fully allocated slabs for debugging purposes.
+ */
+static void add_full(struct kmem_cache *s,
+ struct kmem_cache_node *n, struct page *page)
+{
+ if (!(s->flags & SLAB_STORE_USER))
+ return;
+
+ lockdep_assert_held(&n->list_lock);
+ list_add(&page->lru, &n->full);
+}
+
+static void remove_full(struct kmem_cache *s, struct kmem_cache_node *n, struct page *page)
+{
+ if (!(s->flags & SLAB_STORE_USER))
+ return;
+
+ lockdep_assert_held(&n->list_lock);
+ list_del(&page->lru);
+}
+
+/* Tracking of the number of slabs for debugging purposes */
+static inline unsigned long slabs_node(struct kmem_cache *s, int node)
+{
+ struct kmem_cache_node *n = get_node(s, node);
+
+ return atomic_long_read(&n->nr_slabs);
+}
+
+static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
+{
+ return atomic_long_read(&n->nr_slabs);
+}
+
+static inline void inc_slabs_node(struct kmem_cache *s, int node, int objects)
+{
+ struct kmem_cache_node *n = get_node(s, node);
+
+ /*
+ * May be called early in order to allocate a slab for the
+ * kmem_cache_node structure. Solve the chicken-egg
+ * dilemma by deferring the increment of the count during
+ * bootstrap (see early_kmem_cache_node_alloc).
+ */
+ if (likely(n)) {
+ atomic_long_inc(&n->nr_slabs);
+ atomic_long_add(objects, &n->total_objects);
+ }
+}
+static inline void dec_slabs_node(struct kmem_cache *s, int node, int objects)
+{
+ struct kmem_cache_node *n = get_node(s, node);
+
+ atomic_long_dec(&n->nr_slabs);
+ atomic_long_sub(objects, &n->total_objects);
+}
+
+/* Object debug checks for alloc/free paths */
+static void setup_object_debug(struct kmem_cache *s, struct page *page,
+ void *object)
+{
+ if (!(s->flags & (SLAB_STORE_USER|SLAB_RED_ZONE|__OBJECT_POISON)))
+ return;
+
+ init_object(s, object, SLUB_RED_INACTIVE);
+ init_tracking(s, object);
+}
+
+static noinline int alloc_debug_processing(struct kmem_cache *s,
+ struct page *page,
+ void *object, unsigned long addr)
+{
+ if (!check_slab(s, page))
+ goto bad;
+
+ if (!check_valid_pointer(s, page, object)) {
+ object_err(s, page, object, "Freelist Pointer check fails");
+ goto bad;
+ }
+
+ if (!check_object(s, page, object, SLUB_RED_INACTIVE))
+ goto bad;
+
+ /* Success perform special debug activities for allocs */
+ if (s->flags & SLAB_STORE_USER)
+ set_track(s, object, TRACK_ALLOC, addr);
+ trace(s, page, object, 1);
+ init_object(s, object, SLUB_RED_ACTIVE);
+ return 1;
+
+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 remaining objects.
+ */
+ slab_fix(s, "Marking all objects used");
+ page->inuse = page->objects;
+ page->freelist = NULL;
+ }
+ return 0;
+}
+
+static noinline struct kmem_cache_node *free_debug_processing(
+ struct kmem_cache *s, struct page *page, void *object,
+ unsigned long addr, unsigned long *flags)
+{
+ struct kmem_cache_node *n = get_node(s, page_to_nid(page));
+
+ raw_spin_lock_irqsave(&n->list_lock, *flags);
+ slab_lock(page);
+
+ if (!check_slab(s, page))
+ goto fail;
+
+ if (!check_valid_pointer(s, page, object)) {
+ slab_err(s, page, "Invalid object pointer 0x%p", object);
+ goto fail;
+ }
+
+ if (on_freelist(s, page, object)) {
+ object_err(s, page, object, "Object already free");
+ goto fail;
+ }
+
+ if (!check_object(s, page, object, SLUB_RED_ACTIVE))
+ goto out;
+
+ if (unlikely(s != page->slab_cache)) {
+ if (!PageSlab(page)) {
+ slab_err(s, page, "Attempt to free object(0x%p) "
+ "outside of slab", object);
+ } else if (!page->slab_cache) {
+ pr_err("SLUB <none>: no slab for object 0x%p.\n",
+ object);
+ dump_stack();
+ } else
+ object_err(s, page, object,
+ "page slab pointer corrupt.");
+ goto fail;
+ }
+
+ if (s->flags & SLAB_STORE_USER)
+ set_track(s, object, TRACK_FREE, addr);
+ trace(s, page, object, 0);
+ init_object(s, object, SLUB_RED_INACTIVE);
+out:
+ slab_unlock(page);
+ /*
+ * Keep node_lock to preserve integrity
+ * until the object is actually freed
+ */
+ return n;
+
+fail:
+ slab_unlock(page);
+ raw_spin_unlock_irqrestore(&n->list_lock, *flags);
+ slab_fix(s, "Object at 0x%p not freed", object);
+ return NULL;
+}
+
+static int __init setup_slub_debug(char *str)
+{
+ slub_debug = DEBUG_DEFAULT_FLAGS;
+ if (*str++ != '=' || !*str)
+ /*
+ * No options specified. Switch on full debugging.
+ */
+ goto out;
+
+ if (*str == ',')
+ /*
+ * No options but restriction on slabs. This means full
+ * debugging for slabs matching a pattern.
+ */
+ goto check_slabs;
+
+ slub_debug = 0;
+ if (*str == '-')
+ /*
+ * Switch off all debugging measures.
+ */
+ goto out;
+
+ /*
+ * Determine which debug features should be switched on
+ */
+ for (; *str && *str != ','; str++) {
+ switch (tolower(*str)) {
+ case 'f':
+ slub_debug |= SLAB_DEBUG_FREE;
+ break;
+ case 'z':
+ slub_debug |= SLAB_RED_ZONE;
+ break;
+ case 'p':
+ slub_debug |= SLAB_POISON;
+ break;
+ case 'u':
+ slub_debug |= SLAB_STORE_USER;
+ break;
+ case 't':
+ slub_debug |= SLAB_TRACE;
+ break;
+ case 'a':
+ slub_debug |= SLAB_FAILSLAB;
+ break;
+ case 'o':
+ /*
+ * Avoid enabling debugging on caches if its minimum
+ * order would increase as a result.
+ */
+ disable_higher_order_debug = 1;
+ break;
+ default:
+ pr_err("slub_debug option '%c' unknown. skipped\n",
+ *str);
+ }
+ }
+
+check_slabs:
+ if (*str == ',')
+ slub_debug_slabs = str + 1;
+out:
+ return 1;
+}
+
+__setup("slub_debug", setup_slub_debug);
+
+unsigned long kmem_cache_flags(unsigned long object_size,
+ unsigned long flags, const char *name,
+ void (*ctor)(void *))
+{
+ /*
+ * Enable debugging if selected on the kernel commandline.
+ */
+ if (slub_debug && (!slub_debug_slabs || (name &&
+ !strncmp(slub_debug_slabs, name, strlen(slub_debug_slabs)))))
+ flags |= slub_debug;
+
+ return flags;
+}
+#else
+static inline void setup_object_debug(struct kmem_cache *s,
+ struct page *page, void *object) {}
+
+static inline int alloc_debug_processing(struct kmem_cache *s,
+ struct page *page, void *object, unsigned long addr) { return 0; }
+
+static inline struct kmem_cache_node *free_debug_processing(
+ struct kmem_cache *s, struct page *page, void *object,
+ unsigned long addr, unsigned long *flags) { return NULL; }
+
+static inline int slab_pad_check(struct kmem_cache *s, struct page *page)
+ { return 1; }
+static inline int check_object(struct kmem_cache *s, struct page *page,
+ void *object, u8 val) { return 1; }
+static inline void add_full(struct kmem_cache *s, struct kmem_cache_node *n,
+ struct page *page) {}
+static inline void remove_full(struct kmem_cache *s, struct kmem_cache_node *n,
+ struct page *page) {}
+unsigned long kmem_cache_flags(unsigned long object_size,
+ unsigned long flags, const char *name,
+ void (*ctor)(void *))
+{
+ return flags;
+}
+#define slub_debug 0
+
+#define disable_higher_order_debug 0
+
+static inline unsigned long slabs_node(struct kmem_cache *s, int node)
+ { return 0; }
+static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
+ { return 0; }
+static inline void inc_slabs_node(struct kmem_cache *s, int node,
+ int objects) {}
+static inline void dec_slabs_node(struct kmem_cache *s, int node,
+ int objects) {}
+
+#endif /* CONFIG_SLUB_DEBUG */
+
+struct slub_free_list {
+ raw_spinlock_t lock;
+ struct list_head list;
+};
+static DEFINE_PER_CPU(struct slub_free_list, slub_free_list);
+
+/*
+ * Hooks for other subsystems that check memory allocations. In a typical
+ * production configuration these hooks all should produce no code at all.
+ */
+static inline void kmalloc_large_node_hook(void *ptr, size_t size, gfp_t flags)
+{
+ kmemleak_alloc(ptr, size, 1, flags);
+ kasan_kmalloc_large(ptr, size);
+}
+
+static inline void kfree_hook(const void *x)
+{
+ kmemleak_free(x);
+ kasan_kfree_large(x);
+}
+
+static inline struct kmem_cache *slab_pre_alloc_hook(struct kmem_cache *s,
+ gfp_t flags)
+{
+ flags &= gfp_allowed_mask;
+ lockdep_trace_alloc(flags);
+ might_sleep_if(flags & __GFP_WAIT);
+
+ if (should_failslab(s->object_size, flags, s->flags))
+ return NULL;
+
+ return memcg_kmem_get_cache(s, flags);
+}
+
+static inline void slab_post_alloc_hook(struct kmem_cache *s,
+ gfp_t flags, void *object)
+{
+ flags &= gfp_allowed_mask;
+ kmemcheck_slab_alloc(s, flags, object, slab_ksize(s));
+ kmemleak_alloc_recursive(object, s->object_size, 1, s->flags, flags);
+ memcg_kmem_put_cache(s);
+ kasan_slab_alloc(s, object);
+}
+
+static inline void slab_free_hook(struct kmem_cache *s, void *x)
+{
+ kmemleak_free_recursive(x, s->flags);
+
+ /*
+ * Trouble is that we may no longer disable interrupts in the fast path
+ * So in order to make the debug calls that expect irqs to be
+ * disabled we need to disable interrupts temporarily.
+ */
+#if defined(CONFIG_KMEMCHECK) || defined(CONFIG_LOCKDEP)
+ {
+ unsigned long flags;
+
+ local_irq_save(flags);
+ kmemcheck_slab_free(s, x, s->object_size);
+ debug_check_no_locks_freed(x, s->object_size);
+ local_irq_restore(flags);
+ }
+#endif
+ if (!(s->flags & SLAB_DEBUG_OBJECTS))
+ debug_check_no_obj_freed(x, s->object_size);
+
+ kasan_slab_free(s, x);
+}
+
+static void setup_object(struct kmem_cache *s, struct page *page,
+ void *object)
+{
+ setup_object_debug(s, page, object);
+ if (unlikely(s->ctor)) {
+ kasan_unpoison_object_data(s, object);
+ s->ctor(object);
+ kasan_poison_object_data(s, object);
+ }
+}
+
+/*
+ * Slab allocation and freeing
+ */
+static inline struct page *alloc_slab_page(struct kmem_cache *s,
+ gfp_t flags, int node, struct kmem_cache_order_objects oo)
+{
+ struct page *page;
+ int order = oo_order(oo);
+
+ flags |= __GFP_NOTRACK;
+
+ if (memcg_charge_slab(s, flags, order))
+ return NULL;
+
+ if (node == NUMA_NO_NODE)
+ page = alloc_pages(flags, order);
+ else
+ page = alloc_pages_exact_node(node, flags, order);
+
+ if (!page)
+ memcg_uncharge_slab(s, order);
+
+ return page;
+}
+
+static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
+{
+ struct page *page;
+ struct kmem_cache_order_objects oo = s->oo;
+ gfp_t alloc_gfp;
+ void *start, *p;
+ int idx, order;
+ bool enableirqs;
+
+ flags &= gfp_allowed_mask;
+
+ enableirqs = (flags & __GFP_WAIT) != 0;
+#ifdef CONFIG_PREEMPT_RT_FULL
+ enableirqs |= system_state == SYSTEM_RUNNING;
+#endif
+ if (enableirqs)
+ local_irq_enable();
+
+ flags |= s->allocflags;
+
+ /*
+ * Let the initial higher-order allocation fail under memory pressure
+ * so we fall-back to the minimum order allocation.
+ */
+ alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY) & ~__GFP_NOFAIL;
+
+ page = alloc_slab_page(s, alloc_gfp, node, oo);
+ if (unlikely(!page)) {
+ oo = s->min;
+ alloc_gfp = flags;
+ /*
+ * Allocation may have failed due to fragmentation.
+ * Try a lower order alloc if possible
+ */
+ page = alloc_slab_page(s, alloc_gfp, node, oo);
+ if (unlikely(!page))
+ goto out;
+ stat(s, ORDER_FALLBACK);
+ }
+
+ if (kmemcheck_enabled &&
+ !(s->flags & (SLAB_NOTRACK | DEBUG_DEFAULT_FLAGS))) {
+ int pages = 1 << oo_order(oo);
+
+ kmemcheck_alloc_shadow(page, oo_order(oo), alloc_gfp, node);
+
+ /*
+ * Objects from caches that have a constructor don't get
+ * cleared when they're allocated, so we need to do it here.
+ */
+ if (s->ctor)
+ kmemcheck_mark_uninitialized_pages(page, pages);
+ else
+ kmemcheck_mark_unallocated_pages(page, pages);
+ }
+
+ page->objects = oo_objects(oo);
+
+ order = compound_order(page);
+ page->slab_cache = s;
+ __SetPageSlab(page);
+ if (page->pfmemalloc)
+ SetPageSlabPfmemalloc(page);
+
+ start = page_address(page);
+
+ if (unlikely(s->flags & SLAB_POISON))
+ memset(start, POISON_INUSE, PAGE_SIZE << order);
+
+ kasan_poison_slab(page);
+
+ for_each_object_idx(p, idx, s, start, page->objects) {
+ setup_object(s, page, p);
+ if (likely(idx < page->objects))
+ set_freepointer(s, p, p + s->size);
+ else
+ set_freepointer(s, p, NULL);
+ }
+
+ page->freelist = start;
+ page->inuse = page->objects;
+ page->frozen = 1;
+
+out:
+ if (enableirqs)
+ local_irq_disable();
+ if (!page)
+ return NULL;
+
+ mod_zone_page_state(page_zone(page),
+ (s->flags & SLAB_RECLAIM_ACCOUNT) ?
+ NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
+ 1 << oo_order(oo));
+
+ inc_slabs_node(s, page_to_nid(page), page->objects);
+
+ return page;
+}
+
+static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node)
+{
+ if (unlikely(flags & GFP_SLAB_BUG_MASK)) {
+ pr_emerg("gfp: %u\n", flags & GFP_SLAB_BUG_MASK);
+ BUG();
+ }
+
+ return allocate_slab(s,
+ flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node);
+}
+
+static void __free_slab(struct kmem_cache *s, struct page *page)
+{
+ int order = compound_order(page);
+ int pages = 1 << order;
+
+ if (kmem_cache_debug(s)) {
+ void *p;
+
+ slab_pad_check(s, page);
+ for_each_object(p, s, page_address(page),
+ page->objects)
+ check_object(s, page, p, SLUB_RED_INACTIVE);
+ }
+
+ kmemcheck_free_shadow(page, compound_order(page));
+
+ mod_zone_page_state(page_zone(page),
+ (s->flags & SLAB_RECLAIM_ACCOUNT) ?
+ NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
+ -pages);
+
+ __ClearPageSlabPfmemalloc(page);
+ __ClearPageSlab(page);
+
+ page_mapcount_reset(page);
+ if (current->reclaim_state)
+ current->reclaim_state->reclaimed_slab += pages;
+ __free_pages(page, order);
+ memcg_uncharge_slab(s, order);
+}
+
+static void free_delayed(struct list_head *h)
+{
+ while(!list_empty(h)) {
+ struct page *page = list_first_entry(h, struct page, lru);
+
+ list_del(&page->lru);
+ __free_slab(page->slab_cache, page);
+ }
+}
+
+#define need_reserve_slab_rcu \
+ (sizeof(((struct page *)NULL)->lru) < sizeof(struct rcu_head))
+
+static void rcu_free_slab(struct rcu_head *h)
+{
+ struct page *page;
+
+ if (need_reserve_slab_rcu)
+ page = virt_to_head_page(h);
+ else
+ page = container_of((struct list_head *)h, struct page, lru);
+
+ __free_slab(page->slab_cache, page);
+}
+
+static void free_slab(struct kmem_cache *s, struct page *page)
+{
+ if (unlikely(s->flags & SLAB_DESTROY_BY_RCU)) {
+ struct rcu_head *head;
+
+ if (need_reserve_slab_rcu) {
+ int order = compound_order(page);
+ int offset = (PAGE_SIZE << order) - s->reserved;
+
+ VM_BUG_ON(s->reserved != sizeof(*head));
+ head = page_address(page) + offset;
+ } else {
+ /*
+ * RCU free overloads the RCU head over the LRU
+ */
+ head = (void *)&page->lru;
+ }
+
+ call_rcu(head, rcu_free_slab);
+ } else if (irqs_disabled()) {
+ struct slub_free_list *f = this_cpu_ptr(&slub_free_list);
+
+ raw_spin_lock(&f->lock);
+ list_add(&page->lru, &f->list);
+ raw_spin_unlock(&f->lock);
+ } else
+ __free_slab(s, page);
+}
+
+static void discard_slab(struct kmem_cache *s, struct page *page)
+{
+ dec_slabs_node(s, page_to_nid(page), page->objects);
+ free_slab(s, page);
+}
+
+/*
+ * Management of partially allocated slabs.
+ */
+static inline void
+__add_partial(struct kmem_cache_node *n, struct page *page, int tail)
+{
+ n->nr_partial++;
+ if (tail == DEACTIVATE_TO_TAIL)
+ list_add_tail(&page->lru, &n->partial);
+ else
+ list_add(&page->lru, &n->partial);
+}
+
+static inline void add_partial(struct kmem_cache_node *n,
+ struct page *page, int tail)
+{
+ lockdep_assert_held(&n->list_lock);
+ __add_partial(n, page, tail);
+}
+
+static inline void
+__remove_partial(struct kmem_cache_node *n, struct page *page)
+{
+ list_del(&page->lru);
+ n->nr_partial--;
+}
+
+static inline void remove_partial(struct kmem_cache_node *n,
+ struct page *page)
+{
+ lockdep_assert_held(&n->list_lock);
+ __remove_partial(n, page);
+}
+
+/*
+ * Remove slab from the partial list, freeze it and
+ * return the pointer to the freelist.
+ *
+ * Returns a list of objects or NULL if it fails.
+ */
+static inline void *acquire_slab(struct kmem_cache *s,
+ struct kmem_cache_node *n, struct page *page,
+ int mode, int *objects)
+{
+ void *freelist;
+ unsigned long counters;
+ struct page new;
+
+ lockdep_assert_held(&n->list_lock);
+
+ /*
+ * Zap the freelist and set the frozen bit.
+ * The old freelist is the list of objects for the
+ * per cpu allocation list.
+ */
+ freelist = page->freelist;
+ counters = page->counters;
+ new.counters = counters;
+ *objects = new.objects - new.inuse;
+ if (mode) {
+ new.inuse = page->objects;
+ new.freelist = NULL;
+ } else {
+ new.freelist = freelist;
+ }
+
+ VM_BUG_ON(new.frozen);
+ new.frozen = 1;
+
+ if (!__cmpxchg_double_slab(s, page,
+ freelist, counters,
+ new.freelist, new.counters,
+ "acquire_slab"))
+ return NULL;
+
+ remove_partial(n, page);
+ WARN_ON(!freelist);
+ return freelist;
+}
+
+static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain);
+static inline bool pfmemalloc_match(struct page *page, gfp_t gfpflags);
+
+/*
+ * Try to allocate a partial slab from a specific node.
+ */
+static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n,
+ struct kmem_cache_cpu *c, gfp_t flags)
+{
+ struct page *page, *page2;
+ void *object = NULL;
+ int available = 0;
+ int objects;
+
+ /*
+ * 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 and there is none available then get_partials()
+ * will return NULL.
+ */
+ if (!n || !n->nr_partial)
+ return NULL;
+
+ raw_spin_lock(&n->list_lock);
+ list_for_each_entry_safe(page, page2, &n->partial, lru) {
+ void *t;
+
+ if (!pfmemalloc_match(page, flags))
+ continue;
+
+ t = acquire_slab(s, n, page, object == NULL, &objects);
+ if (!t)
+ break;
+
+ available += objects;
+ if (!object) {
+ c->page = page;
+ stat(s, ALLOC_FROM_PARTIAL);
+ object = t;
+ } else {
+ put_cpu_partial(s, page, 0);
+ stat(s, CPU_PARTIAL_NODE);
+ }
+ if (!kmem_cache_has_cpu_partial(s)
+ || available > s->cpu_partial / 2)
+ break;
+
+ }
+ raw_spin_unlock(&n->list_lock);
+ return object;
+}
+
+/*
+ * Get a page from somewhere. Search in increasing NUMA distances.
+ */
+static void *get_any_partial(struct kmem_cache *s, gfp_t flags,
+ struct kmem_cache_cpu *c)
+{
+#ifdef CONFIG_NUMA
+ struct zonelist *zonelist;
+ struct zoneref *z;
+ struct zone *zone;
+ enum zone_type high_zoneidx = gfp_zone(flags);
+ void *object;
+ unsigned int cpuset_mems_cookie;
+
+ /*
+ * The defrag ratio allows a configuration of the tradeoffs between
+ * inter node defragmentation and node local allocations. A lower
+ * defrag_ratio increases the tendency to do local allocations
+ * instead of attempting to obtain partial slabs from other nodes.
+ *
+ * If the defrag_ratio is set to 0 then kmalloc() always
+ * returns node local objects. If the ratio is higher then kmalloc()
+ * may return off node objects because partial slabs are obtained
+ * from other nodes and filled up.
+ *
+ * If /sys/kernel/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
+ * expensive if we do it every time we are trying to find a slab
+ * with available objects.
+ */
+ if (!s->remote_node_defrag_ratio ||
+ get_cycles() % 1024 > s->remote_node_defrag_ratio)
+ return NULL;
+
+ do {
+ cpuset_mems_cookie = read_mems_allowed_begin();
+ zonelist = node_zonelist(mempolicy_slab_node(), flags);
+ for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) {
+ struct kmem_cache_node *n;
+
+ n = get_node(s, zone_to_nid(zone));
+
+ if (n && cpuset_zone_allowed(zone, flags) &&
+ n->nr_partial > s->min_partial) {
+ object = get_partial_node(s, n, c, flags);
+ if (object) {
+ /*
+ * Don't check read_mems_allowed_retry()
+ * here - if mems_allowed was updated in
+ * parallel, that was a harmless race
+ * between allocation and the cpuset
+ * update
+ */
+ return object;
+ }
+ }
+ }
+ } while (read_mems_allowed_retry(cpuset_mems_cookie));
+#endif
+ return NULL;
+}
+
+/*
+ * Get a partial page, lock it and return it.
+ */
+static void *get_partial(struct kmem_cache *s, gfp_t flags, int node,
+ struct kmem_cache_cpu *c)
+{
+ void *object;
+ int searchnode = node;
+
+ if (node == NUMA_NO_NODE)
+ searchnode = numa_mem_id();
+ else if (!node_present_pages(node))
+ searchnode = node_to_mem_node(node);
+
+ object = get_partial_node(s, get_node(s, searchnode), c, flags);
+ if (object || node != NUMA_NO_NODE)
+ return object;
+
+ return get_any_partial(s, flags, c);
+}
+
+#ifdef CONFIG_PREEMPT
+/*
+ * Calculate the next globally unique transaction for disambiguiation
+ * during cmpxchg. The transactions start with the cpu number and are then
+ * incremented by CONFIG_NR_CPUS.
+ */
+#define TID_STEP roundup_pow_of_two(CONFIG_NR_CPUS)
+#else
+/*
+ * No preemption supported therefore also no need to check for
+ * different cpus.
+ */
+#define TID_STEP 1
+#endif
+
+static inline unsigned long next_tid(unsigned long tid)
+{
+ return tid + TID_STEP;
+}
+
+static inline unsigned int tid_to_cpu(unsigned long tid)
+{
+ return tid % TID_STEP;
+}
+
+static inline unsigned long tid_to_event(unsigned long tid)
+{
+ return tid / TID_STEP;
+}
+
+static inline unsigned int init_tid(int cpu)
+{
+ return cpu;
+}
+
+static inline void note_cmpxchg_failure(const char *n,
+ const struct kmem_cache *s, unsigned long tid)
+{
+#ifdef SLUB_DEBUG_CMPXCHG
+ unsigned long actual_tid = __this_cpu_read(s->cpu_slab->tid);
+
+ pr_info("%s %s: cmpxchg redo ", n, s->name);
+
+#ifdef CONFIG_PREEMPT
+ if (tid_to_cpu(tid) != tid_to_cpu(actual_tid))
+ pr_warn("due to cpu change %d -> %d\n",
+ tid_to_cpu(tid), tid_to_cpu(actual_tid));
+ else
+#endif
+ if (tid_to_event(tid) != tid_to_event(actual_tid))
+ pr_warn("due to cpu running other code. Event %ld->%ld\n",
+ tid_to_event(tid), tid_to_event(actual_tid));
+ else
+ pr_warn("for unknown reason: actual=%lx was=%lx target=%lx\n",
+ actual_tid, tid, next_tid(tid));
+#endif
+ stat(s, CMPXCHG_DOUBLE_CPU_FAIL);
+}
+
+static void init_kmem_cache_cpus(struct kmem_cache *s)
+{
+ int cpu;
+
+ for_each_possible_cpu(cpu)
+ per_cpu_ptr(s->cpu_slab, cpu)->tid = init_tid(cpu);
+}
+
+/*
+ * Remove the cpu slab
+ */
+static void deactivate_slab(struct kmem_cache *s, struct page *page,
+ void *freelist)
+{
+ enum slab_modes { M_NONE, M_PARTIAL, M_FULL, M_FREE };
+ struct kmem_cache_node *n = get_node(s, page_to_nid(page));
+ int lock = 0;
+ enum slab_modes l = M_NONE, m = M_NONE;
+ void *nextfree;
+ int tail = DEACTIVATE_TO_HEAD;
+ struct page new;
+ struct page old;
+
+ if (page->freelist) {
+ stat(s, DEACTIVATE_REMOTE_FREES);
+ tail = DEACTIVATE_TO_TAIL;
+ }
+
+ /*
+ * Stage one: Free all available per cpu objects back
+ * to the page freelist while it is still frozen. Leave the
+ * last one.
+ *
+ * There is no need to take the list->lock because the page
+ * is still frozen.
+ */
+ while (freelist && (nextfree = get_freepointer(s, freelist))) {
+ void *prior;
+ unsigned long counters;
+
+ do {
+ prior = page->freelist;
+ counters = page->counters;
+ set_freepointer(s, freelist, prior);
+ new.counters = counters;
+ new.inuse--;
+ VM_BUG_ON(!new.frozen);
+
+ } while (!__cmpxchg_double_slab(s, page,
+ prior, counters,
+ freelist, new.counters,
+ "drain percpu freelist"));
+
+ freelist = nextfree;
+ }
+
+ /*
+ * Stage two: Ensure that the page is unfrozen while the
+ * list presence reflects the actual number of objects
+ * during unfreeze.
+ *
+ * We setup the list membership and then perform a cmpxchg
+ * with the count. If there is a mismatch then the page
+ * is not unfrozen but the page is on the wrong list.
+ *
+ * Then we restart the process which may have to remove
+ * the page from the list that we just put it on again
+ * because the number of objects in the slab may have
+ * changed.
+ */
+redo:
+
+ old.freelist = page->freelist;
+ old.counters = page->counters;
+ VM_BUG_ON(!old.frozen);
+
+ /* Determine target state of the slab */
+ new.counters = old.counters;
+ if (freelist) {
+ new.inuse--;
+ set_freepointer(s, freelist, old.freelist);
+ new.freelist = freelist;
+ } else
+ new.freelist = old.freelist;
+
+ new.frozen = 0;
+
+ if (!new.inuse && n->nr_partial >= s->min_partial)
+ m = M_FREE;
+ else if (new.freelist) {
+ m = M_PARTIAL;
+ if (!lock) {
+ lock = 1;
+ /*
+ * Taking the spinlock removes the possiblity
+ * that acquire_slab() will see a slab page that
+ * is frozen
+ */
+ raw_spin_lock(&n->list_lock);
+ }
+ } else {
+ m = M_FULL;
+ if (kmem_cache_debug(s) && !lock) {
+ lock = 1;
+ /*
+ * This also ensures that the scanning of full
+ * slabs from diagnostic functions will not see
+ * any frozen slabs.
+ */
+ raw_spin_lock(&n->list_lock);
+ }
+ }
+
+ if (l != m) {
+
+ if (l == M_PARTIAL)
+
+ remove_partial(n, page);
+
+ else if (l == M_FULL)
+
+ remove_full(s, n, page);
+
+ if (m == M_PARTIAL) {
+
+ add_partial(n, page, tail);
+ stat(s, tail);
+
+ } else if (m == M_FULL) {
+
+ stat(s, DEACTIVATE_FULL);
+ add_full(s, n, page);
+
+ }
+ }
+
+ l = m;
+ if (!__cmpxchg_double_slab(s, page,
+ old.freelist, old.counters,
+ new.freelist, new.counters,
+ "unfreezing slab"))
+ goto redo;
+
+ if (lock)
+ raw_spin_unlock(&n->list_lock);
+
+ if (m == M_FREE) {
+ stat(s, DEACTIVATE_EMPTY);
+ discard_slab(s, page);
+ stat(s, FREE_SLAB);
+ }
+}
+
+/*
+ * Unfreeze all the cpu partial slabs.
+ *
+ * This function must be called with interrupts disabled
+ * for the cpu using c (or some other guarantee must be there
+ * to guarantee no concurrent accesses).
+ */
+static void unfreeze_partials(struct kmem_cache *s,
+ struct kmem_cache_cpu *c)
+{
+#ifdef CONFIG_SLUB_CPU_PARTIAL
+ struct kmem_cache_node *n = NULL, *n2 = NULL;
+ struct page *page, *discard_page = NULL;
+
+ while ((page = c->partial)) {
+ struct page new;
+ struct page old;
+
+ c->partial = page->next;
+
+ n2 = get_node(s, page_to_nid(page));
+ if (n != n2) {
+ if (n)
+ raw_spin_unlock(&n->list_lock);
+
+ n = n2;
+ raw_spin_lock(&n->list_lock);
+ }
+
+ do {
+
+ old.freelist = page->freelist;
+ old.counters = page->counters;
+ VM_BUG_ON(!old.frozen);
+
+ new.counters = old.counters;
+ new.freelist = old.freelist;
+
+ new.frozen = 0;
+
+ } while (!__cmpxchg_double_slab(s, page,
+ old.freelist, old.counters,
+ new.freelist, new.counters,
+ "unfreezing slab"));
+
+ if (unlikely(!new.inuse && n->nr_partial >= s->min_partial)) {
+ page->next = discard_page;
+ discard_page = page;
+ } else {
+ add_partial(n, page, DEACTIVATE_TO_TAIL);
+ stat(s, FREE_ADD_PARTIAL);
+ }
+ }
+
+ if (n)
+ raw_spin_unlock(&n->list_lock);
+
+ while (discard_page) {
+ page = discard_page;
+ discard_page = discard_page->next;
+
+ stat(s, DEACTIVATE_EMPTY);
+ discard_slab(s, page);
+ stat(s, FREE_SLAB);
+ }
+#endif
+}
+
+/*
+ * Put a page that was just frozen (in __slab_free) into a partial page
+ * slot if available. This is done without interrupts disabled and without
+ * preemption disabled. The cmpxchg is racy and may put the partial page
+ * onto a random cpus partial slot.
+ *
+ * If we did not find a slot then simply move all the partials to the
+ * per node partial list.
+ */
+static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain)
+{
+#ifdef CONFIG_SLUB_CPU_PARTIAL
+ struct page *oldpage;
+ int pages;
+ int pobjects;
+
+ preempt_disable();
+ do {
+ pages = 0;
+ pobjects = 0;
+ oldpage = this_cpu_read(s->cpu_slab->partial);
+
+ if (oldpage) {
+ pobjects = oldpage->pobjects;
+ pages = oldpage->pages;
+ if (drain && pobjects > s->cpu_partial) {
+ struct slub_free_list *f;
+ unsigned long flags;
+ LIST_HEAD(tofree);
+ /*
+ * partial array is full. Move the existing
+ * set to the per node partial list.
+ */
+ local_irq_save(flags);
+ unfreeze_partials(s, this_cpu_ptr(s->cpu_slab));
+ f = this_cpu_ptr(&slub_free_list);
+ raw_spin_lock(&f->lock);
+ list_splice_init(&f->list, &tofree);
+ raw_spin_unlock(&f->lock);
+ local_irq_restore(flags);
+ free_delayed(&tofree);
+ oldpage = NULL;
+ pobjects = 0;
+ pages = 0;
+ stat(s, CPU_PARTIAL_DRAIN);
+ }
+ }
+
+ pages++;
+ pobjects += page->objects - page->inuse;
+
+ page->pages = pages;
+ page->pobjects = pobjects;
+ page->next = oldpage;
+
+ } while (this_cpu_cmpxchg(s->cpu_slab->partial, oldpage, page)
+ != oldpage);
+ if (unlikely(!s->cpu_partial)) {
+ unsigned long flags;
+
+ local_irq_save(flags);
+ unfreeze_partials(s, this_cpu_ptr(s->cpu_slab));
+ local_irq_restore(flags);
+ }
+ preempt_enable();
+#endif
+}
+
+static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
+{
+ stat(s, CPUSLAB_FLUSH);
+ deactivate_slab(s, c->page, c->freelist);
+
+ c->tid = next_tid(c->tid);
+ c->page = NULL;
+ c->freelist = NULL;
+}
+
+/*
+ * Flush cpu slab.
+ *
+ * Called from IPI handler with interrupts disabled.
+ */
+static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu)
+{
+ struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
+
+ if (likely(c)) {
+ if (c->page)
+ flush_slab(s, c);
+
+ unfreeze_partials(s, c);
+ }
+}
+
+static void flush_cpu_slab(void *d)
+{
+ struct kmem_cache *s = d;
+
+ __flush_cpu_slab(s, smp_processor_id());
+}
+
+static bool has_cpu_slab(int cpu, void *info)
+{
+ struct kmem_cache *s = info;
+ struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
+
+ return c->page || c->partial;
+}
+
+static void flush_all(struct kmem_cache *s)
+{
+ LIST_HEAD(tofree);
+ int cpu;
+
+ on_each_cpu_cond(has_cpu_slab, flush_cpu_slab, s, 1, GFP_ATOMIC);
+ for_each_online_cpu(cpu) {
+ struct slub_free_list *f;
+
+ if (!has_cpu_slab(cpu, s))
+ continue;
+
+ f = &per_cpu(slub_free_list, cpu);
+ raw_spin_lock_irq(&f->lock);
+ list_splice_init(&f->list, &tofree);
+ raw_spin_unlock_irq(&f->lock);
+ free_delayed(&tofree);
+ }
+}
+
+/*
+ * Check if the objects in a per cpu structure fit numa
+ * locality expectations.
+ */
+static inline int node_match(struct page *page, int node)
+{
+#ifdef CONFIG_NUMA
+ if (!page || (node != NUMA_NO_NODE && page_to_nid(page) != node))
+ return 0;
+#endif
+ return 1;
+}
+
+#ifdef CONFIG_SLUB_DEBUG
+static int count_free(struct page *page)
+{
+ return page->objects - page->inuse;
+}
+
+static inline unsigned long node_nr_objs(struct kmem_cache_node *n)
+{
+ return atomic_long_read(&n->total_objects);
+}
+#endif /* CONFIG_SLUB_DEBUG */
+
+#if defined(CONFIG_SLUB_DEBUG) || defined(CONFIG_SYSFS)
+static unsigned long count_partial(struct kmem_cache_node *n,
+ int (*get_count)(struct page *))
+{
+ unsigned long flags;
+ unsigned long x = 0;
+ struct page *page;
+
+ raw_spin_lock_irqsave(&n->list_lock, flags);
+ list_for_each_entry(page, &n->partial, lru)
+ x += get_count(page);
+ raw_spin_unlock_irqrestore(&n->list_lock, flags);
+ return x;
+}
+#endif /* CONFIG_SLUB_DEBUG || CONFIG_SYSFS */
+
+static noinline void
+slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid)
+{
+#ifdef CONFIG_SLUB_DEBUG
+ static DEFINE_RATELIMIT_STATE(slub_oom_rs, DEFAULT_RATELIMIT_INTERVAL,
+ DEFAULT_RATELIMIT_BURST);
+ int node;
+ struct kmem_cache_node *n;
+
+ if ((gfpflags & __GFP_NOWARN) || !__ratelimit(&slub_oom_rs))
+ return;
+
+ pr_warn("SLUB: Unable to allocate memory on node %d (gfp=0x%x)\n",
+ nid, gfpflags);
+ pr_warn(" cache: %s, object size: %d, buffer size: %d, default order: %d, min order: %d\n",
+ s->name, s->object_size, s->size, oo_order(s->oo),
+ oo_order(s->min));
+
+ if (oo_order(s->min) > get_order(s->object_size))
+ pr_warn(" %s debugging increased min order, use slub_debug=O to disable.\n",
+ s->name);
+
+ for_each_kmem_cache_node(s, node, n) {
+ unsigned long nr_slabs;
+ unsigned long nr_objs;
+ unsigned long nr_free;
+
+ nr_free = count_partial(n, count_free);
+ nr_slabs = node_nr_slabs(n);
+ nr_objs = node_nr_objs(n);
+
+ pr_warn(" node %d: slabs: %ld, objs: %ld, free: %ld\n",
+ node, nr_slabs, nr_objs, nr_free);
+ }
+#endif
+}
+
+static inline void *new_slab_objects(struct kmem_cache *s, gfp_t flags,
+ int node, struct kmem_cache_cpu **pc)
+{
+ void *freelist;
+ struct kmem_cache_cpu *c = *pc;
+ struct page *page;
+
+ freelist = get_partial(s, flags, node, c);
+
+ if (freelist)
+ return freelist;
+
+ page = new_slab(s, flags, node);
+ if (page) {
+ c = raw_cpu_ptr(s->cpu_slab);
+ if (c->page)
+ flush_slab(s, c);
+
+ /*
+ * No other reference to the page yet so we can
+ * muck around with it freely without cmpxchg
+ */
+ freelist = page->freelist;
+ page->freelist = NULL;
+
+ stat(s, ALLOC_SLAB);
+ c->page = page;
+ *pc = c;
+ } else
+ freelist = NULL;
+
+ return freelist;
+}
+
+static inline bool pfmemalloc_match(struct page *page, gfp_t gfpflags)
+{
+ if (unlikely(PageSlabPfmemalloc(page)))
+ return gfp_pfmemalloc_allowed(gfpflags);
+
+ return true;
+}
+
+/*
+ * Check the page->freelist of a page and either transfer the freelist to the
+ * per cpu freelist or deactivate the page.
+ *
+ * The page is still frozen if the return value is not NULL.
+ *
+ * If this function returns NULL then the page has been unfrozen.
+ *
+ * This function must be called with interrupt disabled.
+ */
+static inline void *get_freelist(struct kmem_cache *s, struct page *page)
+{
+ struct page new;
+ unsigned long counters;
+ void *freelist;
+
+ do {
+ freelist = page->freelist;
+ counters = page->counters;
+
+ new.counters = counters;
+ VM_BUG_ON(!new.frozen);
+
+ new.inuse = page->objects;
+ new.frozen = freelist != NULL;
+
+ } while (!__cmpxchg_double_slab(s, page,
+ freelist, counters,
+ NULL, new.counters,
+ "get_freelist"));
+
+ return freelist;
+}
+
+/*
+ * Slow path. The lockless freelist is empty or we need to perform
+ * debugging duties.
+ *
+ * Processing is still very fast if new objects have been freed to the
+ * regular freelist. In that case we simply take over the regular freelist
+ * as the lockless freelist and zap the regular freelist.
+ *
+ * If that is not working then we fall back to the partial lists. We take the
+ * first element of the freelist as the object to allocate now and move the
+ * rest of the freelist to the lockless freelist.
+ *
+ * And if we were unable to get a new slab from the partial slab lists then
+ * we need to allocate a new slab. This is the slowest path since it involves
+ * a call to the page allocator and the setup of a new slab.
+ */
+static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
+ unsigned long addr, struct kmem_cache_cpu *c)
+{
+ struct slub_free_list *f;
+ void *freelist;
+ struct page *page;
+ unsigned long flags;
+ LIST_HEAD(tofree);
+
+ local_irq_save(flags);
+#ifdef CONFIG_PREEMPT
+ /*
+ * We may have been preempted and rescheduled on a different
+ * cpu before disabling interrupts. Need to reload cpu area
+ * pointer.
+ */
+ c = this_cpu_ptr(s->cpu_slab);
+#endif
+
+ page = c->page;
+ if (!page)
+ goto new_slab;
+redo:
+
+ if (unlikely(!node_match(page, node))) {
+ int searchnode = node;
+
+ if (node != NUMA_NO_NODE && !node_present_pages(node))
+ searchnode = node_to_mem_node(node);
+
+ if (unlikely(!node_match(page, searchnode))) {
+ stat(s, ALLOC_NODE_MISMATCH);
+ deactivate_slab(s, page, c->freelist);
+ c->page = NULL;
+ c->freelist = NULL;
+ goto new_slab;
+ }
+ }
+
+ /*
+ * By rights, we should be searching for a slab page that was
+ * PFMEMALLOC but right now, we are losing the pfmemalloc
+ * information when the page leaves the per-cpu allocator
+ */
+ if (unlikely(!pfmemalloc_match(page, gfpflags))) {
+ deactivate_slab(s, page, c->freelist);
+ c->page = NULL;
+ c->freelist = NULL;
+ goto new_slab;
+ }
+
+ /* must check again c->freelist in case of cpu migration or IRQ */
+ freelist = c->freelist;
+ if (freelist)
+ goto load_freelist;
+
+ freelist = get_freelist(s, page);
+
+ if (!freelist) {
+ c->page = NULL;
+ stat(s, DEACTIVATE_BYPASS);
+ goto new_slab;
+ }
+
+ stat(s, ALLOC_REFILL);
+
+load_freelist:
+ /*
+ * freelist is pointing to the list of objects to be used.
+ * page is pointing to the page from which the objects are obtained.
+ * That page must be frozen for per cpu allocations to work.
+ */
+ VM_BUG_ON(!c->page->frozen);
+ c->freelist = get_freepointer(s, freelist);
+ c->tid = next_tid(c->tid);
+out:
+ f = this_cpu_ptr(&slub_free_list);
+ raw_spin_lock(&f->lock);
+ list_splice_init(&f->list, &tofree);
+ raw_spin_unlock(&f->lock);
+ local_irq_restore(flags);
+ free_delayed(&tofree);
+ return freelist;
+
+new_slab:
+
+ if (c->partial) {
+ page = c->page = c->partial;
+ c->partial = page->next;
+ stat(s, CPU_PARTIAL_ALLOC);
+ c->freelist = NULL;
+ goto redo;
+ }
+
+ freelist = new_slab_objects(s, gfpflags, node, &c);
+
+ if (unlikely(!freelist)) {
+ slab_out_of_memory(s, gfpflags, node);
+ goto out;
+ }
+
+ page = c->page;
+ if (likely(!kmem_cache_debug(s) && pfmemalloc_match(page, gfpflags)))
+ goto load_freelist;
+
+ /* Only entered in the debug case */
+ if (kmem_cache_debug(s) &&
+ !alloc_debug_processing(s, page, freelist, addr))
+ goto new_slab; /* Slab failed checks. Next slab needed */
+
+ deactivate_slab(s, page, get_freepointer(s, freelist));
+ c->page = NULL;
+ c->freelist = NULL;
+ goto out;
+}
+
+/*
+ * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc)
+ * have the fastpath folded into their functions. So no function call
+ * overhead for requests that can be satisfied on the fastpath.
+ *
+ * The fastpath works by first checking if the lockless freelist can be used.
+ * If not then __slab_alloc is called for slow processing.
+ *
+ * Otherwise we can simply pick the next object from the lockless free list.
+ */
+static __always_inline void *slab_alloc_node(struct kmem_cache *s,
+ gfp_t gfpflags, int node, unsigned long addr)
+{
+ void **object;
+ struct kmem_cache_cpu *c;
+ struct page *page;
+ unsigned long tid;
+
+ s = slab_pre_alloc_hook(s, gfpflags);
+ if (!s)
+ return NULL;
+redo:
+ /*
+ * Must read kmem_cache cpu data via this cpu ptr. Preemption is
+ * enabled. We may switch back and forth between cpus while
+ * reading from one cpu area. That does not matter as long
+ * as we end up on the original cpu again when doing the cmpxchg.
+ *
+ * We should guarantee that tid and kmem_cache are retrieved on
+ * the same cpu. It could be different if CONFIG_PREEMPT so we need
+ * to check if it is matched or not.
+ */
+ do {
+ tid = this_cpu_read(s->cpu_slab->tid);
+ c = raw_cpu_ptr(s->cpu_slab);
+ } while (IS_ENABLED(CONFIG_PREEMPT) &&
+ unlikely(tid != READ_ONCE(c->tid)));
+
+ /*
+ * Irqless object alloc/free algorithm used here depends on sequence
+ * of fetching cpu_slab's data. tid should be fetched before anything
+ * on c to guarantee that object and page associated with previous tid
+ * won't be used with current tid. If we fetch tid first, object and
+ * page could be one associated with next tid and our alloc/free
+ * request will be failed. In this case, we will retry. So, no problem.
+ */
+ barrier();
+
+ /*
+ * The transaction ids are globally unique per cpu and per operation on
+ * a per cpu queue. Thus they can be guarantee that the cmpxchg_double
+ * occurs on the right processor and that there was no operation on the
+ * linked list in between.
+ */
+
+ object = c->freelist;
+ page = c->page;
+ if (unlikely(!object || !node_match(page, node))) {
+ object = __slab_alloc(s, gfpflags, node, addr, c);
+ stat(s, ALLOC_SLOWPATH);
+ } else {
+ void *next_object = get_freepointer_safe(s, object);
+
+ /*
+ * The cmpxchg will only match if there was no additional
+ * operation and if we are on the right processor.
+ *
+ * The cmpxchg does the following atomically (without lock
+ * semantics!)
+ * 1. Relocate first pointer to the current per cpu area.
+ * 2. Verify that tid and freelist have not been changed
+ * 3. If they were not changed replace tid and freelist
+ *
+ * Since this is without lock semantics the protection is only
+ * against code executing on this cpu *not* from access by
+ * other cpus.
+ */
+ if (unlikely(!this_cpu_cmpxchg_double(
+ s->cpu_slab->freelist, s->cpu_slab->tid,
+ object, tid,
+ next_object, next_tid(tid)))) {
+
+ note_cmpxchg_failure("slab_alloc", s, tid);
+ goto redo;
+ }
+ prefetch_freepointer(s, next_object);
+ stat(s, ALLOC_FASTPATH);
+ }
+
+ if (unlikely(gfpflags & __GFP_ZERO) && object)
+ memset(object, 0, s->object_size);
+
+ slab_post_alloc_hook(s, gfpflags, object);
+
+ return object;
+}
+
+static __always_inline void *slab_alloc(struct kmem_cache *s,
+ gfp_t gfpflags, unsigned long addr)
+{
+ return slab_alloc_node(s, gfpflags, NUMA_NO_NODE, addr);
+}
+
+void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags)
+{
+ void *ret = slab_alloc(s, gfpflags, _RET_IP_);
+
+ trace_kmem_cache_alloc(_RET_IP_, ret, s->object_size,
+ s->size, gfpflags);
+
+ return ret;
+}
+EXPORT_SYMBOL(kmem_cache_alloc);
+
+#ifdef CONFIG_TRACING
+void *kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size)
+{
+ void *ret = slab_alloc(s, gfpflags, _RET_IP_);
+ trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags);
+ kasan_kmalloc(s, ret, size);
+ return ret;
+}
+EXPORT_SYMBOL(kmem_cache_alloc_trace);
+#endif
+
+#ifdef CONFIG_NUMA
+void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node)
+{
+ void *ret = slab_alloc_node(s, gfpflags, node, _RET_IP_);
+
+ trace_kmem_cache_alloc_node(_RET_IP_, ret,
+ s->object_size, s->size, gfpflags, node);
+
+ return ret;
+}
+EXPORT_SYMBOL(kmem_cache_alloc_node);
+
+#ifdef CONFIG_TRACING
+void *kmem_cache_alloc_node_trace(struct kmem_cache *s,
+ gfp_t gfpflags,
+ int node, size_t size)
+{
+ void *ret = slab_alloc_node(s, gfpflags, node, _RET_IP_);
+
+ trace_kmalloc_node(_RET_IP_, ret,
+ size, s->size, gfpflags, node);
+
+ kasan_kmalloc(s, ret, size);
+ return ret;
+}
+EXPORT_SYMBOL(kmem_cache_alloc_node_trace);
+#endif
+#endif
+
+/*
+ * Slow path handling. This may still be called frequently since objects
+ * have a longer lifetime than the cpu slabs in most processing loads.
+ *
+ * So we still attempt to reduce cache line usage. Just take the slab
+ * lock and free the item. If there is no additional partial page
+ * handling required then we can return immediately.
+ */
+static void __slab_free(struct kmem_cache *s, struct page *page,
+ void *x, unsigned long addr)
+{
+ void *prior;
+ void **object = (void *)x;
+ int was_frozen;
+ struct page new;
+ unsigned long counters;
+ struct kmem_cache_node *n = NULL;
+ unsigned long uninitialized_var(flags);
+
+ stat(s, FREE_SLOWPATH);
+
+ if (kmem_cache_debug(s) &&
+ !(n = free_debug_processing(s, page, x, addr, &flags)))
+ return;
+
+ do {
+ if (unlikely(n)) {
+ raw_spin_unlock_irqrestore(&n->list_lock, flags);
+ n = NULL;
+ }
+ prior = page->freelist;
+ counters = page->counters;
+ set_freepointer(s, object, prior);
+ new.counters = counters;
+ was_frozen = new.frozen;
+ new.inuse--;
+ if ((!new.inuse || !prior) && !was_frozen) {
+
+ if (kmem_cache_has_cpu_partial(s) && !prior) {
+
+ /*
+ * Slab was on no list before and will be
+ * partially empty
+ * We can defer the list move and instead
+ * freeze it.
+ */
+ new.frozen = 1;
+
+ } else { /* Needs to be taken off a list */
+
+ n = get_node(s, page_to_nid(page));
+ /*
+ * Speculatively acquire the list_lock.
+ * If the cmpxchg does not succeed then we may
+ * drop the list_lock without any processing.
+ *
+ * Otherwise the list_lock will synchronize with
+ * other processors updating the list of slabs.
+ */
+ raw_spin_lock_irqsave(&n->list_lock, flags);
+
+ }
+ }
+
+ } while (!cmpxchg_double_slab(s, page,
+ prior, counters,
+ object, new.counters,
+ "__slab_free"));
+
+ if (likely(!n)) {
+
+ /*
+ * If we just froze the page then put it onto the
+ * per cpu partial list.
+ */
+ if (new.frozen && !was_frozen) {
+ put_cpu_partial(s, page, 1);
+ stat(s, CPU_PARTIAL_FREE);
+ }
+ /*
+ * The list lock was not taken therefore no list
+ * activity can be necessary.
+ */
+ if (was_frozen)
+ stat(s, FREE_FROZEN);
+ return;
+ }
+
+ if (unlikely(!new.inuse && n->nr_partial >= s->min_partial))
+ goto slab_empty;
+
+ /*
+ * Objects left in the slab. If it was not on the partial list before
+ * then add it.
+ */
+ if (!kmem_cache_has_cpu_partial(s) && unlikely(!prior)) {
+ if (kmem_cache_debug(s))
+ remove_full(s, n, page);
+ add_partial(n, page, DEACTIVATE_TO_TAIL);
+ stat(s, FREE_ADD_PARTIAL);
+ }
+ raw_spin_unlock_irqrestore(&n->list_lock, flags);
+ return;
+
+slab_empty:
+ if (prior) {
+ /*
+ * Slab on the partial list.
+ */
+ remove_partial(n, page);
+ stat(s, FREE_REMOVE_PARTIAL);
+ } else {
+ /* Slab must be on the full list */
+ remove_full(s, n, page);
+ }
+
+ raw_spin_unlock_irqrestore(&n->list_lock, flags);
+ stat(s, FREE_SLAB);
+ discard_slab(s, page);
+}
+
+/*
+ * Fastpath with forced inlining to produce a kfree and kmem_cache_free that
+ * can perform fastpath freeing without additional function calls.
+ *
+ * The fastpath is only possible if we are freeing to the current cpu slab
+ * of this processor. This typically the case if we have just allocated
+ * the item before.
+ *
+ * If fastpath is not possible then fall back to __slab_free where we deal
+ * with all sorts of special processing.
+ */
+static __always_inline void slab_free(struct kmem_cache *s,
+ struct page *page, void *x, unsigned long addr)
+{
+ void **object = (void *)x;
+ struct kmem_cache_cpu *c;
+ unsigned long tid;
+
+ slab_free_hook(s, x);
+
+redo:
+ /*
+ * Determine the currently cpus per cpu slab.
+ * The cpu may change afterward. However that does not matter since
+ * data is retrieved via this pointer. If we are on the same cpu
+ * during the cmpxchg then the free will succedd.
+ */
+ do {
+ tid = this_cpu_read(s->cpu_slab->tid);
+ c = raw_cpu_ptr(s->cpu_slab);
+ } while (IS_ENABLED(CONFIG_PREEMPT) &&
+ unlikely(tid != READ_ONCE(c->tid)));
+
+ /* Same with comment on barrier() in slab_alloc_node() */
+ barrier();
+
+ if (likely(page == c->page)) {
+ set_freepointer(s, object, c->freelist);
+
+ if (unlikely(!this_cpu_cmpxchg_double(
+ s->cpu_slab->freelist, s->cpu_slab->tid,
+ c->freelist, tid,
+ object, next_tid(tid)))) {
+
+ note_cmpxchg_failure("slab_free", s, tid);
+ goto redo;
+ }
+ stat(s, FREE_FASTPATH);
+ } else
+ __slab_free(s, page, x, addr);
+
+}
+
+void kmem_cache_free(struct kmem_cache *s, void *x)
+{
+ s = cache_from_obj(s, x);
+ if (!s)
+ return;
+ slab_free(s, virt_to_head_page(x), x, _RET_IP_);
+ trace_kmem_cache_free(_RET_IP_, x);
+}
+EXPORT_SYMBOL(kmem_cache_free);
+
+/*
+ * Object placement in a slab is made very easy because we always start at
+ * offset 0. If we tune the size of the object to the alignment then we can
+ * get the required alignment by putting one properly sized object after
+ * another.
+ *
+ * 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 is therefore a factor in
+ * locking overhead.
+ */
+
+/*
+ * 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 = PAGE_ALLOC_COSTLY_ORDER;
+static int slub_min_objects;
+
+/*
+ * Calculate the order of allocation given an slab object size.
+ *
+ * The order of allocation has significant impact on performance and other
+ * system components. Generally order 0 allocations should be preferred since
+ * order 0 does not cause fragmentation in the page allocator. Larger objects
+ * be problematic to put into order 0 slabs because there may be too much
+ * unused space left. We go to a higher order if more than 1/16th 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 which requires taking the list_lock. This is
+ * less a concern for large slabs though which are rarely used.
+ *
+ * slub_max_order specifies the order where we begin to stop considering the
+ * number of objects in a slab as critical. If we reach slub_max_order then
+ * we try to keep the page order as low as possible. So we accept more waste
+ * of space in favor of a small page order.
+ *
+ * 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
+ * the smallest order which will fit the object.
+ */
+static inline int slab_order(int size, int min_objects,
+ int max_order, int fract_leftover, int reserved)
+{
+ int order;
+ int rem;
+ int min_order = slub_min_order;
+
+ if (order_objects(min_order, size, reserved) > MAX_OBJS_PER_PAGE)
+ return get_order(size * MAX_OBJS_PER_PAGE) - 1;
+
+ for (order = max(min_order,
+ fls(min_objects * size - 1) - PAGE_SHIFT);
+ order <= max_order; order++) {
+
+ unsigned long slab_size = PAGE_SIZE << order;
+
+ if (slab_size < min_objects * size + reserved)
+ continue;
+
+ rem = (slab_size - reserved) % size;
+
+ if (rem <= slab_size / fract_leftover)
+ break;
+
+ }
+
+ return order;
+}
+
+static inline int calculate_order(int size, int reserved)
+{
+ int order;
+ int min_objects;
+ int fraction;
+ int max_objects;
+
+ /*
+ * Attempt to find best configuration for a slab. This
+ * works by first attempting to generate a layout with
+ * the best configuration and backing off gradually.
+ *
+ * First we reduce the acceptable waste in a slab. Then
+ * we reduce the minimum objects required in a slab.
+ */
+ min_objects = slub_min_objects;
+ if (!min_objects)
+ min_objects = 4 * (fls(nr_cpu_ids) + 1);
+ max_objects = order_objects(slub_max_order, size, reserved);
+ min_objects = min(min_objects, max_objects);
+
+ while (min_objects > 1) {
+ fraction = 16;
+ while (fraction >= 4) {
+ order = slab_order(size, min_objects,
+ slub_max_order, fraction, reserved);
+ if (order <= slub_max_order)
+ return order;
+ fraction /= 2;
+ }
+ min_objects--;
+ }
+
+ /*
+ * We were unable to place multiple objects in a slab. Now
+ * lets see if we can place a single object there.
+ */
+ order = slab_order(size, 1, slub_max_order, 1, reserved);
+ if (order <= slub_max_order)
+ return order;
+
+ /*
+ * Doh this slab cannot be placed using slub_max_order.
+ */
+ order = slab_order(size, 1, MAX_ORDER, 1, reserved);
+ if (order < MAX_ORDER)
+ return order;
+ return -ENOSYS;
+}
+
+static void
+init_kmem_cache_node(struct kmem_cache_node *n)
+{
+ n->nr_partial = 0;
+ raw_spin_lock_init(&n->list_lock);
+ INIT_LIST_HEAD(&n->partial);
+#ifdef CONFIG_SLUB_DEBUG
+ atomic_long_set(&n->nr_slabs, 0);
+ atomic_long_set(&n->total_objects, 0);
+ INIT_LIST_HEAD(&n->full);
+#endif
+}
+
+static inline int alloc_kmem_cache_cpus(struct kmem_cache *s)
+{
+ BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE <
+ KMALLOC_SHIFT_HIGH * sizeof(struct kmem_cache_cpu));
+
+ /*
+ * Must align to double word boundary for the double cmpxchg
+ * instructions to work; see __pcpu_double_call_return_bool().
+ */
+ s->cpu_slab = __alloc_percpu(sizeof(struct kmem_cache_cpu),
+ 2 * sizeof(void *));
+
+ if (!s->cpu_slab)
+ return 0;
+
+ init_kmem_cache_cpus(s);
+
+ return 1;
+}
+
+static struct kmem_cache *kmem_cache_node;
+
+/*
+ * 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 kmem_cache_node
+ * when allocating for the kmem_cache_node. This is used for bootstrapping
+ * memory on a fresh node that has no slab structures yet.
+ */
+static void early_kmem_cache_node_alloc(int node)
+{
+ struct page *page;
+ struct kmem_cache_node *n;
+
+ BUG_ON(kmem_cache_node->size < sizeof(struct kmem_cache_node));
+
+ page = new_slab(kmem_cache_node, GFP_NOWAIT, node);
+
+ BUG_ON(!page);
+ if (page_to_nid(page) != node) {
+ pr_err("SLUB: Unable to allocate memory from node %d\n", node);
+ pr_err("SLUB: Allocating a useless per node structure in order to be able to continue\n");
+ }
+
+ n = page->freelist;
+ BUG_ON(!n);
+ page->freelist = get_freepointer(kmem_cache_node, n);
+ page->inuse = 1;
+ page->frozen = 0;
+ kmem_cache_node->node[node] = n;
+#ifdef CONFIG_SLUB_DEBUG
+ init_object(kmem_cache_node, n, SLUB_RED_ACTIVE);
+ init_tracking(kmem_cache_node, n);
+#endif
+ kasan_kmalloc(kmem_cache_node, n, sizeof(struct kmem_cache_node));
+ init_kmem_cache_node(n);
+ inc_slabs_node(kmem_cache_node, node, page->objects);
+
+ /*
+ * No locks need to be taken here as it has just been
+ * initialized and there is no concurrent access.
+ */
+ __add_partial(n, page, DEACTIVATE_TO_HEAD);
+}
+
+static void free_kmem_cache_nodes(struct kmem_cache *s)
+{
+ int node;
+ struct kmem_cache_node *n;
+
+ for_each_kmem_cache_node(s, node, n) {
+ kmem_cache_free(kmem_cache_node, n);
+ s->node[node] = NULL;
+ }
+}
+
+static int init_kmem_cache_nodes(struct kmem_cache *s)
+{
+ int node;
+
+ for_each_node_state(node, N_NORMAL_MEMORY) {
+ struct kmem_cache_node *n;
+
+ if (slab_state == DOWN) {
+ early_kmem_cache_node_alloc(node);
+ continue;
+ }
+ n = kmem_cache_alloc_node(kmem_cache_node,
+ GFP_KERNEL, node);
+
+ if (!n) {
+ free_kmem_cache_nodes(s);
+ return 0;
+ }
+
+ s->node[node] = n;
+ init_kmem_cache_node(n);
+ }
+ return 1;
+}
+
+static void set_min_partial(struct kmem_cache *s, unsigned long min)
+{
+ if (min < MIN_PARTIAL)
+ min = MIN_PARTIAL;
+ else if (min > MAX_PARTIAL)
+ min = MAX_PARTIAL;
+ s->min_partial = min;
+}
+
+/*
+ * calculate_sizes() determines the order and the distribution of data within
+ * a slab object.
+ */
+static int calculate_sizes(struct kmem_cache *s, int forced_order)
+{
+ unsigned long flags = s->flags;
+ unsigned long size = s->object_size;
+ int order;
+
+ /*
+ * 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 *));
+
+#ifdef CONFIG_SLUB_DEBUG
+ /*
+ * 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->flags |= __OBJECT_POISON;
+ else
+ s->flags &= ~__OBJECT_POISON;
+
+
+ /*
+ * 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 to have some bytes to store Redzone information.
+ */
+ if ((flags & SLAB_RED_ZONE) && size == s->object_size)
+ size += sizeof(void *);
+#endif
+
+ /*
+ * With that we have determined the number of bytes 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)) {
+ /*
+ * 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 *);
+ }
+
+#ifdef CONFIG_SLUB_DEBUG
+ if (flags & SLAB_STORE_USER)
+ /*
+ * Need to store information about allocs and frees after
+ * the object.
+ */
+ size += 2 * sizeof(struct track);
+
+ if (flags & SLAB_RED_ZONE)
+ /*
+ * 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 a user writes before the start
+ * of the object.
+ */
+ size += sizeof(void *);
+#endif
+
+ /*
+ * 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, s->align);
+ s->size = size;
+ if (forced_order >= 0)
+ order = forced_order;
+ else
+ order = calculate_order(size, s->reserved);
+
+ if (order < 0)
+ return 0;
+
+ s->allocflags = 0;
+ if (order)
+ s->allocflags |= __GFP_COMP;
+
+ if (s->flags & SLAB_CACHE_DMA)
+ s->allocflags |= GFP_DMA;
+
+ if (s->flags & SLAB_RECLAIM_ACCOUNT)
+ s->allocflags |= __GFP_RECLAIMABLE;
+
+ /*
+ * Determine the number of objects per slab
+ */
+ s->oo = oo_make(order, size, s->reserved);
+ s->min = oo_make(get_order(size), size, s->reserved);
+ if (oo_objects(s->oo) > oo_objects(s->max))
+ s->max = s->oo;
+
+ return !!oo_objects(s->oo);
+}
+
+static int kmem_cache_open(struct kmem_cache *s, unsigned long flags)
+{
+ s->flags = kmem_cache_flags(s->size, flags, s->name, s->ctor);
+ s->reserved = 0;
+
+ if (need_reserve_slab_rcu && (s->flags & SLAB_DESTROY_BY_RCU))
+ s->reserved = sizeof(struct rcu_head);
+
+ if (!calculate_sizes(s, -1))
+ goto error;
+ if (disable_higher_order_debug) {
+ /*
+ * Disable debugging flags that store metadata if the min slab
+ * order increased.
+ */
+ if (get_order(s->size) > get_order(s->object_size)) {
+ s->flags &= ~DEBUG_METADATA_FLAGS;
+ s->offset = 0;
+ if (!calculate_sizes(s, -1))
+ goto error;
+ }
+ }
+
+#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
+ defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
+ if (system_has_cmpxchg_double() && (s->flags & SLAB_DEBUG_FLAGS) == 0)
+ /* Enable fast mode */
+ s->flags |= __CMPXCHG_DOUBLE;
+#endif
+
+ /*
+ * The larger the object size is, the more pages we want on the partial
+ * list to avoid pounding the page allocator excessively.
+ */
+ set_min_partial(s, ilog2(s->size) / 2);
+
+ /*
+ * cpu_partial determined the maximum number of objects kept in the
+ * per cpu partial lists of a processor.
+ *
+ * Per cpu partial lists mainly contain slabs that just have one
+ * object freed. If they are used for allocation then they can be
+ * filled up again with minimal effort. The slab will never hit the
+ * per node partial lists and therefore no locking will be required.
+ *
+ * This setting also determines
+ *
+ * A) The number of objects from per cpu partial slabs dumped to the
+ * per node list when we reach the limit.
+ * B) The number of objects in cpu partial slabs to extract from the
+ * per node list when we run out of per cpu objects. We only fetch
+ * 50% to keep some capacity around for frees.
+ */
+ if (!kmem_cache_has_cpu_partial(s))
+ s->cpu_partial = 0;
+ else if (s->size >= PAGE_SIZE)
+ s->cpu_partial = 2;
+ else if (s->size >= 1024)
+ s->cpu_partial = 6;
+ else if (s->size >= 256)
+ s->cpu_partial = 13;
+ else
+ s->cpu_partial = 30;
+
+#ifdef CONFIG_NUMA
+ s->remote_node_defrag_ratio = 1000;
+#endif
+ if (!init_kmem_cache_nodes(s))
+ goto error;
+
+ if (alloc_kmem_cache_cpus(s))
+ return 0;
+
+ free_kmem_cache_nodes(s);
+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)s->size, s->size,
+ oo_order(s->oo), s->offset, flags);
+ return -EINVAL;
+}
+
+static void list_slab_objects(struct kmem_cache *s, struct page *page,
+ const char *text)
+{
+#ifdef CONFIG_SLUB_DEBUG
+ void *addr = page_address(page);
+ void *p;
+ unsigned long *map = kzalloc(BITS_TO_LONGS(page->objects) *
+ sizeof(long), GFP_ATOMIC);
+ if (!map)
+ return;
+ slab_err(s, page, text, s->name);
+ slab_lock(page);
+
+ get_map(s, page, map);
+ for_each_object(p, s, addr, page->objects) {
+
+ if (!test_bit(slab_index(p, s, addr), map)) {
+ pr_err("INFO: Object 0x%p @offset=%tu\n", p, p - addr);
+ print_tracking(s, p);
+ }
+ }
+ slab_unlock(page);
+ kfree(map);
+#endif
+}
+
+/*
+ * Attempt to free all partial slabs on a node.
+ * This is called from kmem_cache_close(). We must be the last thread
+ * using the cache and therefore we do not need to lock anymore.
+ */
+static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
+{
+ struct page *page, *h;
+
+ list_for_each_entry_safe(page, h, &n->partial, lru) {
+ if (!page->inuse) {
+ __remove_partial(n, page);
+ discard_slab(s, page);
+ } else {
+ list_slab_objects(s, page,
+ "Objects remaining in %s on kmem_cache_close()");
+ }
+ }
+}
+
+/*
+ * Release all resources used by a slab cache.
+ */
+static inline int kmem_cache_close(struct kmem_cache *s)
+{
+ int node;
+ struct kmem_cache_node *n;
+
+ flush_all(s);
+ /* Attempt to free all objects */
+ for_each_kmem_cache_node(s, node, n) {
+ free_partial(s, n);
+ if (n->nr_partial || slabs_node(s, node))
+ return 1;
+ }
+ free_percpu(s->cpu_slab);
+ free_kmem_cache_nodes(s);
+ return 0;
+}
+
+int __kmem_cache_shutdown(struct kmem_cache *s)
+{
+ return kmem_cache_close(s);
+}
+
+/********************************************************************
+ * Kmalloc subsystem
+ *******************************************************************/
+
+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);
+ slub_max_order = min(slub_max_order, MAX_ORDER - 1);
+
+ 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);
+
+void *__kmalloc(size_t size, gfp_t flags)
+{
+ struct kmem_cache *s;
+ void *ret;
+
+ if (unlikely(size > KMALLOC_MAX_CACHE_SIZE))
+ return kmalloc_large(size, flags);
+
+ s = kmalloc_slab(size, flags);
+
+ if (unlikely(ZERO_OR_NULL_PTR(s)))
+ return s;
+
+ ret = slab_alloc(s, flags, _RET_IP_);
+
+ trace_kmalloc(_RET_IP_, ret, size, s->size, flags);
+
+ kasan_kmalloc(s, ret, size);
+
+ return ret;
+}
+EXPORT_SYMBOL(__kmalloc);
+
+#ifdef CONFIG_NUMA
+static void *kmalloc_large_node(size_t size, gfp_t flags, int node)
+{
+ struct page *page;
+ void *ptr = NULL;
+
+ flags |= __GFP_COMP | __GFP_NOTRACK;
+ page = alloc_kmem_pages_node(node, flags, get_order(size));
+ if (page)
+ ptr = page_address(page);
+
+ kmalloc_large_node_hook(ptr, size, flags);
+ return ptr;
+}
+
+void *__kmalloc_node(size_t size, gfp_t flags, int node)
+{
+ struct kmem_cache *s;
+ void *ret;
+
+ if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) {
+ ret = kmalloc_large_node(size, flags, node);
+
+ trace_kmalloc_node(_RET_IP_, ret,
+ size, PAGE_SIZE << get_order(size),
+ flags, node);
+
+ return ret;
+ }
+
+ s = kmalloc_slab(size, flags);
+
+ if (unlikely(ZERO_OR_NULL_PTR(s)))
+ return s;
+
+ ret = slab_alloc_node(s, flags, node, _RET_IP_);
+
+ trace_kmalloc_node(_RET_IP_, ret, size, s->size, flags, node);
+
+ kasan_kmalloc(s, ret, size);
+
+ return ret;
+}
+EXPORT_SYMBOL(__kmalloc_node);
+#endif
+
+static size_t __ksize(const void *object)
+{
+ struct page *page;
+
+ if (unlikely(object == ZERO_SIZE_PTR))
+ return 0;
+
+ page = virt_to_head_page(object);
+
+ if (unlikely(!PageSlab(page))) {
+ WARN_ON(!PageCompound(page));
+ return PAGE_SIZE << compound_order(page);
+ }
+
+ return slab_ksize(page->slab_cache);
+}
+
+size_t ksize(const void *object)
+{
+ size_t size = __ksize(object);
+ /* We assume that ksize callers could use whole allocated area,
+ so we need unpoison this area. */
+ kasan_krealloc(object, size);
+ return size;
+}
+EXPORT_SYMBOL(ksize);
+
+void kfree(const void *x)
+{
+ struct page *page;
+ void *object = (void *)x;
+
+ trace_kfree(_RET_IP_, x);
+
+ if (unlikely(ZERO_OR_NULL_PTR(x)))
+ return;
+
+ page = virt_to_head_page(x);
+ if (unlikely(!PageSlab(page))) {
+ BUG_ON(!PageCompound(page));
+ kfree_hook(x);
+ __free_kmem_pages(page, compound_order(page));
+ return;
+ }
+ slab_free(page->slab_cache, page, object, _RET_IP_);
+}
+EXPORT_SYMBOL(kfree);
+
+#define SHRINK_PROMOTE_MAX 32
+
+/*
+ * kmem_cache_shrink discards empty slabs and promotes the slabs filled
+ * up most to the head of the partial lists. New allocations will then
+ * fill those up and thus they can be removed from the partial lists.
+ *
+ * The slabs with the least items are placed last. This results in them
+ * being allocated from last increasing the chance that the last objects
+ * are freed in them.
+ */
+int __kmem_cache_shrink(struct kmem_cache *s, bool deactivate)
+{
+ int node;
+ int i;
+ struct kmem_cache_node *n;
+ struct page *page;
+ struct page *t;
+ struct list_head discard;
+ struct list_head promote[SHRINK_PROMOTE_MAX];
+ unsigned long flags;
+ int ret = 0;
+
+ if (deactivate) {
+ /*
+ * Disable empty slabs caching. Used to avoid pinning offline
+ * memory cgroups by kmem pages that can be freed.
+ */
+ s->cpu_partial = 0;
+ s->min_partial = 0;
+
+ /*
+ * s->cpu_partial is checked locklessly (see put_cpu_partial),
+ * so we have to make sure the change is visible.
+ */
+ kick_all_cpus_sync();
+ }
+
+ flush_all(s);
+ for_each_kmem_cache_node(s, node, n) {
+ INIT_LIST_HEAD(&discard);
+ for (i = 0; i < SHRINK_PROMOTE_MAX; i++)
+ INIT_LIST_HEAD(promote + i);
+
+ raw_spin_lock_irqsave(&n->list_lock, flags);
+
+ /*
+ * Build lists of slabs to discard or promote.
+ *
+ * Note that concurrent frees may occur while we hold the
+ * list_lock. page->inuse here is the upper limit.
+ */
+ list_for_each_entry_safe(page, t, &n->partial, lru) {
+ int free = page->objects - page->inuse;
+
+ /* Do not reread page->inuse */
+ barrier();
+
+ /* We do not keep full slabs on the list */
+ BUG_ON(free <= 0);
+
+ if (free == page->objects) {
+ list_move(&page->lru, &discard);
+ n->nr_partial--;
+ } else if (free <= SHRINK_PROMOTE_MAX)
+ list_move(&page->lru, promote + free - 1);
+ }
+
+ /*
+ * Promote the slabs filled up most to the head of the
+ * partial list.
+ */
+ for (i = SHRINK_PROMOTE_MAX - 1; i >= 0; i--)
+ list_splice(promote + i, &n->partial);
+
+ raw_spin_unlock_irqrestore(&n->list_lock, flags);
+
+ /* Release empty slabs */
+ list_for_each_entry_safe(page, t, &discard, lru)
+ discard_slab(s, page);
+
+ if (slabs_node(s, node))
+ ret = 1;
+ }
+
+ return ret;
+}
+
+static int slab_mem_going_offline_callback(void *arg)
+{
+ struct kmem_cache *s;
+
+ mutex_lock(&slab_mutex);
+ list_for_each_entry(s, &slab_caches, list)
+ __kmem_cache_shrink(s, false);
+ mutex_unlock(&slab_mutex);
+
+ return 0;
+}
+
+static void slab_mem_offline_callback(void *arg)
+{
+ struct kmem_cache_node *n;
+ struct kmem_cache *s;
+ struct memory_notify *marg = arg;
+ int offline_node;
+
+ offline_node = marg->status_change_nid_normal;
+
+ /*
+ * If the node still has available memory. we need kmem_cache_node
+ * for it yet.
+ */
+ if (offline_node < 0)
+ return;
+
+ mutex_lock(&slab_mutex);
+ list_for_each_entry(s, &slab_caches, list) {
+ n = get_node(s, offline_node);
+ if (n) {
+ /*
+ * if n->nr_slabs > 0, slabs still exist on the node
+ * that is going down. We were unable to free them,
+ * and offline_pages() function shouldn't call this
+ * callback. So, we must fail.
+ */
+ BUG_ON(slabs_node(s, offline_node));
+
+ s->node[offline_node] = NULL;
+ kmem_cache_free(kmem_cache_node, n);
+ }
+ }
+ mutex_unlock(&slab_mutex);
+}
+
+static int slab_mem_going_online_callback(void *arg)
+{
+ struct kmem_cache_node *n;
+ struct kmem_cache *s;
+ struct memory_notify *marg = arg;
+ int nid = marg->status_change_nid_normal;
+ int ret = 0;
+
+ /*
+ * If the node's memory is already available, then kmem_cache_node is
+ * already created. Nothing to do.
+ */
+ if (nid < 0)
+ return 0;
+
+ /*
+ * We are bringing a node online. No memory is available yet. We must
+ * allocate a kmem_cache_node structure in order to bring the node
+ * online.
+ */
+ mutex_lock(&slab_mutex);
+ list_for_each_entry(s, &slab_caches, list) {
+ /*
+ * XXX: kmem_cache_alloc_node will fallback to other nodes
+ * since memory is not yet available from the node that
+ * is brought up.
+ */
+ n = kmem_cache_alloc(kmem_cache_node, GFP_KERNEL);
+ if (!n) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ init_kmem_cache_node(n);
+ s->node[nid] = n;
+ }
+out:
+ mutex_unlock(&slab_mutex);
+ return ret;
+}
+
+static int slab_memory_callback(struct notifier_block *self,
+ unsigned long action, void *arg)
+{
+ int ret = 0;
+
+ switch (action) {
+ case MEM_GOING_ONLINE:
+ ret = slab_mem_going_online_callback(arg);
+ break;
+ case MEM_GOING_OFFLINE:
+ ret = slab_mem_going_offline_callback(arg);
+ break;
+ case MEM_OFFLINE:
+ case MEM_CANCEL_ONLINE:
+ slab_mem_offline_callback(arg);
+ break;
+ case MEM_ONLINE:
+ case MEM_CANCEL_OFFLINE:
+ break;
+ }
+ if (ret)
+ ret = notifier_from_errno(ret);
+ else
+ ret = NOTIFY_OK;
+ return ret;
+}
+
+static struct notifier_block slab_memory_callback_nb = {
+ .notifier_call = slab_memory_callback,
+ .priority = SLAB_CALLBACK_PRI,
+};
+
+/********************************************************************
+ * Basic setup of slabs
+ *******************************************************************/
+
+/*
+ * Used for early kmem_cache structures that were allocated using
+ * the page allocator. Allocate them properly then fix up the pointers
+ * that may be pointing to the wrong kmem_cache structure.
+ */
+
+static struct kmem_cache * __init bootstrap(struct kmem_cache *static_cache)
+{
+ int node;
+ struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
+ struct kmem_cache_node *n;
+
+ memcpy(s, static_cache, kmem_cache->object_size);
+
+ /*
+ * This runs very early, and only the boot processor is supposed to be
+ * up. Even if it weren't true, IRQs are not up so we couldn't fire
+ * IPIs around.
+ */
+ __flush_cpu_slab(s, smp_processor_id());
+ for_each_kmem_cache_node(s, node, n) {
+ struct page *p;
+
+ list_for_each_entry(p, &n->partial, lru)
+ p->slab_cache = s;
+
+#ifdef CONFIG_SLUB_DEBUG
+ list_for_each_entry(p, &n->full, lru)
+ p->slab_cache = s;
+#endif
+ }
+ slab_init_memcg_params(s);
+ list_add(&s->list, &slab_caches);
+ return s;
+}
+
+void __init kmem_cache_init(void)
+{
+ static __initdata struct kmem_cache boot_kmem_cache,
+ boot_kmem_cache_node;
+ int cpu;
+
+ for_each_possible_cpu(cpu) {
+ raw_spin_lock_init(&per_cpu(slub_free_list, cpu).lock);
+ INIT_LIST_HEAD(&per_cpu(slub_free_list, cpu).list);
+ }
+
+ if (debug_guardpage_minorder())
+ slub_max_order = 0;
+
+ kmem_cache_node = &boot_kmem_cache_node;
+ kmem_cache = &boot_kmem_cache;
+
+ create_boot_cache(kmem_cache_node, "kmem_cache_node",
+ sizeof(struct kmem_cache_node), SLAB_HWCACHE_ALIGN);
+
+ register_hotmemory_notifier(&slab_memory_callback_nb);
+
+ /* Able to allocate the per node structures */
+ slab_state = PARTIAL;
+
+ create_boot_cache(kmem_cache, "kmem_cache",
+ offsetof(struct kmem_cache, node) +
+ nr_node_ids * sizeof(struct kmem_cache_node *),
+ SLAB_HWCACHE_ALIGN);
+
+ kmem_cache = bootstrap(&boot_kmem_cache);
+
+ /*
+ * Allocate kmem_cache_node properly from the kmem_cache slab.
+ * kmem_cache_node is separately allocated so no need to
+ * update any list pointers.
+ */
+ kmem_cache_node = bootstrap(&boot_kmem_cache_node);
+
+ /* Now we can use the kmem_cache to allocate kmalloc slabs */
+ create_kmalloc_caches(0);
+
+#ifdef CONFIG_SMP
+ register_cpu_notifier(&slab_notifier);
+#endif
+
+ pr_info("SLUB: HWalign=%d, Order=%d-%d, MinObjects=%d, CPUs=%d, Nodes=%d\n",
+ cache_line_size(),
+ slub_min_order, slub_max_order, slub_min_objects,
+ nr_cpu_ids, nr_node_ids);
+}
+
+void __init kmem_cache_init_late(void)
+{
+}
+
+struct kmem_cache *
+__kmem_cache_alias(const char *name, size_t size, size_t align,
+ unsigned long flags, void (*ctor)(void *))
+{
+ struct kmem_cache *s, *c;
+
+ s = find_mergeable(size, align, flags, name, ctor);
+ if (s) {
+ s->refcount++;
+
+ /*
+ * Adjust the object sizes so that we clear
+ * the complete object on kzalloc.
+ */
+ s->object_size = max(s->object_size, (int)size);
+ s->inuse = max_t(int, s->inuse, ALIGN(size, sizeof(void *)));
+
+ for_each_memcg_cache(c, s) {
+ c->object_size = s->object_size;
+ c->inuse = max_t(int, c->inuse,
+ ALIGN(size, sizeof(void *)));
+ }
+
+ if (sysfs_slab_alias(s, name)) {
+ s->refcount--;
+ s = NULL;
+ }
+ }
+
+ return s;
+}
+
+int __kmem_cache_create(struct kmem_cache *s, unsigned long flags)
+{
+ int err;
+
+ err = kmem_cache_open(s, flags);
+ if (err)
+ return err;
+
+ /* Mutex is not taken during early boot */
+ if (slab_state <= UP)
+ return 0;
+
+ memcg_propagate_slab_attrs(s);
+ err = sysfs_slab_add(s);
+ if (err)
+ kmem_cache_close(s);
+
+ return err;
+}
+
+#ifdef CONFIG_SMP
+/*
+ * Use the cpu notifier to insure that the cpu slabs are flushed when
+ * necessary.
+ */
+static int slab_cpuup_callback(struct notifier_block *nfb,
+ unsigned long action, void *hcpu)
+{
+ long cpu = (long)hcpu;
+ struct kmem_cache *s;
+ unsigned long flags;
+
+ switch (action) {
+ case CPU_UP_CANCELED:
+ case CPU_UP_CANCELED_FROZEN:
+ case CPU_DEAD:
+ case CPU_DEAD_FROZEN:
+ mutex_lock(&slab_mutex);
+ list_for_each_entry(s, &slab_caches, list) {
+ local_irq_save(flags);
+ __flush_cpu_slab(s, cpu);
+ local_irq_restore(flags);
+ }
+ mutex_unlock(&slab_mutex);
+ break;
+ default:
+ break;
+ }
+ return NOTIFY_OK;
+}
+
+static struct notifier_block slab_notifier = {
+ .notifier_call = slab_cpuup_callback
+};
+
+#endif
+
+void *__kmalloc_track_caller(size_t size, gfp_t gfpflags, unsigned long caller)
+{
+ struct kmem_cache *s;
+ void *ret;
+
+ if (unlikely(size > KMALLOC_MAX_CACHE_SIZE))
+ return kmalloc_large(size, gfpflags);
+
+ s = kmalloc_slab(size, gfpflags);
+
+ if (unlikely(ZERO_OR_NULL_PTR(s)))
+ return s;
+
+ ret = slab_alloc(s, gfpflags, caller);
+
+ /* Honor the call site pointer we received. */
+ trace_kmalloc(caller, ret, size, s->size, gfpflags);
+
+ return ret;
+}
+
+#ifdef CONFIG_NUMA
+void *__kmalloc_node_track_caller(size_t size, gfp_t gfpflags,
+ int node, unsigned long caller)
+{
+ struct kmem_cache *s;
+ void *ret;
+
+ if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) {
+ ret = kmalloc_large_node(size, gfpflags, node);
+
+ trace_kmalloc_node(caller, ret,
+ size, PAGE_SIZE << get_order(size),
+ gfpflags, node);
+
+ return ret;
+ }
+
+ s = kmalloc_slab(size, gfpflags);
+
+ if (unlikely(ZERO_OR_NULL_PTR(s)))
+ return s;
+
+ ret = slab_alloc_node(s, gfpflags, node, caller);
+
+ /* Honor the call site pointer we received. */
+ trace_kmalloc_node(caller, ret, size, s->size, gfpflags, node);
+
+ return ret;
+}
+#endif
+
+#ifdef CONFIG_SYSFS
+static int count_inuse(struct page *page)
+{
+ return page->inuse;
+}
+
+static int count_total(struct page *page)
+{
+ return page->objects;
+}
+#endif
+
+#ifdef CONFIG_SLUB_DEBUG
+static int validate_slab(struct kmem_cache *s, struct page *page,
+ unsigned long *map)
+{
+ void *p;
+ void *addr = page_address(page);
+
+ if (!check_slab(s, page) ||
+ !on_freelist(s, page, NULL))
+ return 0;
+
+ /* Now we know that a valid freelist exists */
+ bitmap_zero(map, page->objects);
+
+ get_map(s, page, map);
+ for_each_object(p, s, addr, page->objects) {
+ if (test_bit(slab_index(p, s, addr), map))
+ if (!check_object(s, page, p, SLUB_RED_INACTIVE))
+ return 0;
+ }
+
+ for_each_object(p, s, addr, page->objects)
+ if (!test_bit(slab_index(p, s, addr), map))
+ if (!check_object(s, page, p, SLUB_RED_ACTIVE))
+ return 0;
+ return 1;
+}
+
+static void validate_slab_slab(struct kmem_cache *s, struct page *page,
+ unsigned long *map)
+{
+ slab_lock(page);
+ validate_slab(s, page, map);
+ slab_unlock(page);
+}
+
+static int validate_slab_node(struct kmem_cache *s,
+ struct kmem_cache_node *n, unsigned long *map)
+{
+ unsigned long count = 0;
+ struct page *page;
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&n->list_lock, flags);
+
+ list_for_each_entry(page, &n->partial, lru) {
+ validate_slab_slab(s, page, map);
+ count++;
+ }
+ if (count != n->nr_partial)
+ pr_err("SLUB %s: %ld partial slabs counted but counter=%ld\n",
+ s->name, count, n->nr_partial);
+
+ if (!(s->flags & SLAB_STORE_USER))
+ goto out;
+
+ list_for_each_entry(page, &n->full, lru) {
+ validate_slab_slab(s, page, map);
+ count++;
+ }
+ if (count != atomic_long_read(&n->nr_slabs))
+ pr_err("SLUB: %s %ld slabs counted but counter=%ld\n",
+ s->name, count, atomic_long_read(&n->nr_slabs));
+
+out:
+ raw_spin_unlock_irqrestore(&n->list_lock, flags);
+ return count;
+}
+
+static long validate_slab_cache(struct kmem_cache *s)
+{
+ int node;
+ unsigned long count = 0;
+ unsigned long *map = kmalloc(BITS_TO_LONGS(oo_objects(s->max)) *
+ sizeof(unsigned long), GFP_KERNEL);
+ struct kmem_cache_node *n;
+
+ if (!map)
+ return -ENOMEM;
+
+ flush_all(s);
+ for_each_kmem_cache_node(s, node, n)
+ count += validate_slab_node(s, n, map);
+ kfree(map);
+ return count;
+}
+/*
+ * Generate lists of code addresses where slabcache objects are allocated
+ * and freed.
+ */
+
+struct location {
+ unsigned long count;
+ unsigned long addr;
+ long long sum_time;
+ long min_time;
+ long max_time;
+ long min_pid;
+ long max_pid;
+ DECLARE_BITMAP(cpus, NR_CPUS);
+ nodemask_t nodes;
+};
+
+struct loc_track {
+ unsigned long max;
+ unsigned long count;
+ struct location *loc;
+};
+
+static void free_loc_track(struct loc_track *t)
+{
+ if (t->max)
+ free_pages((unsigned long)t->loc,
+ get_order(sizeof(struct location) * t->max));
+}
+
+static int alloc_loc_track(struct loc_track *t, unsigned long max, gfp_t flags)
+{
+ struct location *l;
+ int order;
+
+ order = get_order(sizeof(struct location) * max);
+
+ l = (void *)__get_free_pages(flags, order);
+ if (!l)
+ return 0;
+
+ if (t->count) {
+ memcpy(l, t->loc, sizeof(struct location) * t->count);
+ free_loc_track(t);
+ }
+ t->max = max;
+ t->loc = l;
+ return 1;
+}
+
+static int add_location(struct loc_track *t, struct kmem_cache *s,
+ const struct track *track)
+{
+ long start, end, pos;
+ struct location *l;
+ unsigned long caddr;
+ unsigned long age = jiffies - track->when;
+
+ start = -1;
+ end = t->count;
+
+ for ( ; ; ) {
+ pos = start + (end - start + 1) / 2;
+
+ /*
+ * There is nothing at "end". If we end up there
+ * we need to add something to before end.
+ */
+ if (pos == end)
+ break;
+
+ caddr = t->loc[pos].addr;
+ if (track->addr == caddr) {
+
+ l = &t->loc[pos];
+ l->count++;
+ if (track->when) {
+ l->sum_time += age;
+ if (age < l->min_time)
+ l->min_time = age;
+ if (age > l->max_time)
+ l->max_time = age;
+
+ if (track->pid < l->min_pid)
+ l->min_pid = track->pid;
+ if (track->pid > l->max_pid)
+ l->max_pid = track->pid;
+
+ cpumask_set_cpu(track->cpu,
+ to_cpumask(l->cpus));
+ }
+ node_set(page_to_nid(virt_to_page(track)), l->nodes);
+ return 1;
+ }
+
+ if (track->addr < caddr)
+ end = pos;
+ else
+ start = pos;
+ }
+
+ /*
+ * Not found. Insert new tracking element.
+ */
+ if (t->count >= t->max && !alloc_loc_track(t, 2 * t->max, GFP_ATOMIC))
+ return 0;
+
+ l = t->loc + pos;
+ if (pos < t->count)
+ memmove(l + 1, l,
+ (t->count - pos) * sizeof(struct location));
+ t->count++;
+ l->count = 1;
+ l->addr = track->addr;
+ l->sum_time = age;
+ l->min_time = age;
+ l->max_time = age;
+ l->min_pid = track->pid;
+ l->max_pid = track->pid;
+ cpumask_clear(to_cpumask(l->cpus));
+ cpumask_set_cpu(track->cpu, to_cpumask(l->cpus));
+ nodes_clear(l->nodes);
+ node_set(page_to_nid(virt_to_page(track)), l->nodes);
+ return 1;
+}
+
+static void process_slab(struct loc_track *t, struct kmem_cache *s,
+ struct page *page, enum track_item alloc,
+ unsigned long *map)
+{
+ void *addr = page_address(page);
+ void *p;
+
+ bitmap_zero(map, page->objects);
+ get_map(s, page, map);
+
+ for_each_object(p, s, addr, page->objects)
+ if (!test_bit(slab_index(p, s, addr), map))
+ add_location(t, s, get_track(s, p, alloc));
+}
+
+static int list_locations(struct kmem_cache *s, char *buf,
+ enum track_item alloc)
+{
+ int len = 0;
+ unsigned long i;
+ struct loc_track t = { 0, 0, NULL };
+ int node;
+ unsigned long *map = kmalloc(BITS_TO_LONGS(oo_objects(s->max)) *
+ sizeof(unsigned long), GFP_KERNEL);
+ struct kmem_cache_node *n;
+
+ if (!map || !alloc_loc_track(&t, PAGE_SIZE / sizeof(struct location),
+ GFP_TEMPORARY)) {
+ kfree(map);
+ return sprintf(buf, "Out of memory\n");
+ }
+ /* Push back cpu slabs */
+ flush_all(s);
+
+ for_each_kmem_cache_node(s, node, n) {
+ unsigned long flags;
+ struct page *page;
+
+ if (!atomic_long_read(&n->nr_slabs))
+ continue;
+
+ raw_spin_lock_irqsave(&n->list_lock, flags);
+ list_for_each_entry(page, &n->partial, lru)
+ process_slab(&t, s, page, alloc, map);
+ list_for_each_entry(page, &n->full, lru)
+ process_slab(&t, s, page, alloc, map);
+ raw_spin_unlock_irqrestore(&n->list_lock, flags);
+ }
+
+ for (i = 0; i < t.count; i++) {
+ struct location *l = &t.loc[i];
+
+ if (len > PAGE_SIZE - KSYM_SYMBOL_LEN - 100)
+ break;
+ len += sprintf(buf + len, "%7ld ", l->count);
+
+ if (l->addr)
+ len += sprintf(buf + len, "%pS", (void *)l->addr);
+ else
+ len += sprintf(buf + len, "<not-available>");
+
+ if (l->sum_time != l->min_time) {
+ len += sprintf(buf + len, " age=%ld/%ld/%ld",
+ l->min_time,
+ (long)div_u64(l->sum_time, l->count),
+ l->max_time);
+ } else
+ len += sprintf(buf + len, " age=%ld",
+ l->min_time);
+
+ if (l->min_pid != l->max_pid)
+ len += sprintf(buf + len, " pid=%ld-%ld",
+ l->min_pid, l->max_pid);
+ else
+ len += sprintf(buf + len, " pid=%ld",
+ l->min_pid);
+
+ if (num_online_cpus() > 1 &&
+ !cpumask_empty(to_cpumask(l->cpus)) &&
+ len < PAGE_SIZE - 60)
+ len += scnprintf(buf + len, PAGE_SIZE - len - 50,
+ " cpus=%*pbl",
+ cpumask_pr_args(to_cpumask(l->cpus)));
+
+ if (nr_online_nodes > 1 && !nodes_empty(l->nodes) &&
+ len < PAGE_SIZE - 60)
+ len += scnprintf(buf + len, PAGE_SIZE - len - 50,
+ " nodes=%*pbl",
+ nodemask_pr_args(&l->nodes));
+
+ len += sprintf(buf + len, "\n");
+ }
+
+ free_loc_track(&t);
+ kfree(map);
+ if (!t.count)
+ len += sprintf(buf, "No data\n");
+ return len;
+}
+#endif
+
+#ifdef SLUB_RESILIENCY_TEST
+static void __init resiliency_test(void)
+{
+ u8 *p;
+
+ BUILD_BUG_ON(KMALLOC_MIN_SIZE > 16 || KMALLOC_SHIFT_HIGH < 10);
+
+ pr_err("SLUB resiliency testing\n");
+ pr_err("-----------------------\n");
+ pr_err("A. Corruption after allocation\n");
+
+ p = kzalloc(16, GFP_KERNEL);
+ p[16] = 0x12;
+ pr_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;
+ pr_err("\n2. kmalloc-32: Clobber next pointer/next slab 0x34 -> -0x%p\n",
+ p);
+ pr_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;
+ pr_err("\n3. kmalloc-64: corrupting random byte 0x56->0x%p\n",
+ p);
+ pr_err("If allocated object is overwritten then not detectable\n\n");
+ validate_slab_cache(kmalloc_caches[6]);
+
+ pr_err("\nB. Corruption after free\n");
+ p = kzalloc(128, GFP_KERNEL);
+ kfree(p);
+ *p = 0x78;
+ pr_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;
+ pr_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;
+ pr_err("\n3. kmalloc-512: Clobber redzone 0xab->0x%p\n\n", p);
+ validate_slab_cache(kmalloc_caches[9]);
+}
+#else
+#ifdef CONFIG_SYSFS
+static void resiliency_test(void) {};
+#endif
+#endif
+
+#ifdef CONFIG_SYSFS
+enum slab_stat_type {
+ SL_ALL, /* All slabs */
+ SL_PARTIAL, /* Only partially allocated slabs */
+ SL_CPU, /* Only slabs used for cpu caches */
+ SL_OBJECTS, /* Determine allocated objects not slabs */
+ SL_TOTAL /* Determine object capacity not slabs */
+};
+
+#define SO_ALL (1 << SL_ALL)
+#define SO_PARTIAL (1 << SL_PARTIAL)
+#define SO_CPU (1 << SL_CPU)
+#define SO_OBJECTS (1 << SL_OBJECTS)
+#define SO_TOTAL (1 << SL_TOTAL)
+
+static ssize_t show_slab_objects(struct kmem_cache *s,
+ char *buf, unsigned long flags)
+{
+ unsigned long total = 0;
+ int node;
+ int x;
+ unsigned long *nodes;
+
+ nodes = kzalloc(sizeof(unsigned long) * nr_node_ids, GFP_KERNEL);
+ if (!nodes)
+ return -ENOMEM;
+
+ if (flags & SO_CPU) {
+ int cpu;
+
+ for_each_possible_cpu(cpu) {
+ struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab,
+ cpu);
+ int node;
+ struct page *page;
+
+ page = READ_ONCE(c->page);
+ if (!page)
+ continue;
+
+ node = page_to_nid(page);
+ if (flags & SO_TOTAL)
+ x = page->objects;
+ else if (flags & SO_OBJECTS)
+ x = page->inuse;
+ else
+ x = 1;
+
+ total += x;
+ nodes[node] += x;
+
+ page = READ_ONCE(c->partial);
+ if (page) {
+ node = page_to_nid(page);
+ if (flags & SO_TOTAL)
+ WARN_ON_ONCE(1);
+ else if (flags & SO_OBJECTS)
+ WARN_ON_ONCE(1);
+ else
+ x = page->pages;
+ total += x;
+ nodes[node] += x;
+ }
+ }
+ }
+
+ get_online_mems();
+#ifdef CONFIG_SLUB_DEBUG
+ if (flags & SO_ALL) {
+ struct kmem_cache_node *n;
+
+ for_each_kmem_cache_node(s, node, n) {
+
+ if (flags & SO_TOTAL)
+ x = atomic_long_read(&n->total_objects);
+ else if (flags & SO_OBJECTS)
+ x = atomic_long_read(&n->total_objects) -
+ count_partial(n, count_free);
+ else
+ x = atomic_long_read(&n->nr_slabs);
+ total += x;
+ nodes[node] += x;
+ }
+
+ } else
+#endif
+ if (flags & SO_PARTIAL) {
+ struct kmem_cache_node *n;
+
+ for_each_kmem_cache_node(s, node, n) {
+ if (flags & SO_TOTAL)
+ x = count_partial(n, count_total);
+ else if (flags & SO_OBJECTS)
+ x = count_partial(n, count_inuse);
+ else
+ x = n->nr_partial;
+ total += x;
+ nodes[node] += x;
+ }
+ }
+ x = sprintf(buf, "%lu", total);
+#ifdef CONFIG_NUMA
+ for (node = 0; node < nr_node_ids; node++)
+ if (nodes[node])
+ x += sprintf(buf + x, " N%d=%lu",
+ node, nodes[node]);
+#endif
+ put_online_mems();
+ kfree(nodes);
+ return x + sprintf(buf + x, "\n");
+}
+
+#ifdef CONFIG_SLUB_DEBUG
+static int any_slab_objects(struct kmem_cache *s)
+{
+ int node;
+ struct kmem_cache_node *n;
+
+ for_each_kmem_cache_node(s, node, n)
+ if (atomic_long_read(&n->total_objects))
+ return 1;
+
+ return 0;
+}
+#endif
+
+#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(_name, 0400, _name##_show, NULL)
+
+#define SLAB_ATTR(_name) \
+ static struct slab_attribute _name##_attr = \
+ __ATTR(_name, 0600, _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->object_size);
+}
+SLAB_ATTR_RO(object_size);
+
+static ssize_t objs_per_slab_show(struct kmem_cache *s, char *buf)
+{
+ return sprintf(buf, "%d\n", oo_objects(s->oo));
+}
+SLAB_ATTR_RO(objs_per_slab);
+
+static ssize_t order_store(struct kmem_cache *s,
+ const char *buf, size_t length)
+{
+ unsigned long order;
+ int err;
+
+ err = kstrtoul(buf, 10, &order);
+ if (err)
+ return err;
+
+ if (order > slub_max_order || order < slub_min_order)
+ return -EINVAL;
+
+ calculate_sizes(s, order);
+ return length;
+}
+
+static ssize_t order_show(struct kmem_cache *s, char *buf)
+{
+ return sprintf(buf, "%d\n", oo_order(s->oo));
+}
+SLAB_ATTR(order);
+
+static ssize_t min_partial_show(struct kmem_cache *s, char *buf)
+{
+ return sprintf(buf, "%lu\n", s->min_partial);
+}
+
+static ssize_t min_partial_store(struct kmem_cache *s, const char *buf,
+ size_t length)
+{
+ unsigned long min;
+ int err;
+
+ err = kstrtoul(buf, 10, &min);
+ if (err)
+ return err;
+
+ set_min_partial(s, min);
+ return length;
+}
+SLAB_ATTR(min_partial);
+
+static ssize_t cpu_partial_show(struct kmem_cache *s, char *buf)
+{
+ return sprintf(buf, "%u\n", s->cpu_partial);
+}
+
+static ssize_t cpu_partial_store(struct kmem_cache *s, const char *buf,
+ size_t length)
+{
+ unsigned long objects;
+ int err;
+
+ err = kstrtoul(buf, 10, &objects);
+ if (err)
+ return err;
+ if (objects && !kmem_cache_has_cpu_partial(s))
+ return -EINVAL;
+
+ s->cpu_partial = objects;
+ flush_all(s);
+ return length;
+}
+SLAB_ATTR(cpu_partial);
+
+static ssize_t ctor_show(struct kmem_cache *s, char *buf)
+{
+ if (!s->ctor)
+ return 0;
+ return sprintf(buf, "%pS\n", s->ctor);
+}
+SLAB_ATTR_RO(ctor);
+
+static ssize_t aliases_show(struct kmem_cache *s, char *buf)
+{
+ return sprintf(buf, "%d\n", s->refcount < 0 ? 0 : s->refcount - 1);
+}
+SLAB_ATTR_RO(aliases);
+
+static ssize_t partial_show(struct kmem_cache *s, char *buf)
+{
+ return show_slab_objects(s, buf, SO_PARTIAL);
+}
+SLAB_ATTR_RO(partial);
+
+static ssize_t cpu_slabs_show(struct kmem_cache *s, char *buf)
+{
+ return show_slab_objects(s, buf, SO_CPU);
+}
+SLAB_ATTR_RO(cpu_slabs);
+
+static ssize_t objects_show(struct kmem_cache *s, char *buf)
+{
+ return show_slab_objects(s, buf, SO_ALL|SO_OBJECTS);
+}
+SLAB_ATTR_RO(objects);
+
+static ssize_t objects_partial_show(struct kmem_cache *s, char *buf)
+{
+ return show_slab_objects(s, buf, SO_PARTIAL|SO_OBJECTS);
+}
+SLAB_ATTR_RO(objects_partial);
+
+static ssize_t slabs_cpu_partial_show(struct kmem_cache *s, char *buf)
+{
+ int objects = 0;
+ int pages = 0;
+ int cpu;
+ int len;
+
+ for_each_online_cpu(cpu) {
+ struct page *page = per_cpu_ptr(s->cpu_slab, cpu)->partial;
+
+ if (page) {
+ pages += page->pages;
+ objects += page->pobjects;
+ }
+ }
+
+ len = sprintf(buf, "%d(%d)", objects, pages);
+
+#ifdef CONFIG_SMP
+ for_each_online_cpu(cpu) {
+ struct page *page = per_cpu_ptr(s->cpu_slab, cpu) ->partial;
+
+ if (page && len < PAGE_SIZE - 20)
+ len += sprintf(buf + len, " C%d=%d(%d)", cpu,
+ page->pobjects, page->pages);
+ }
+#endif
+ return len + sprintf(buf + len, "\n");
+}
+SLAB_ATTR_RO(slabs_cpu_partial);
+
+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_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 reserved_show(struct kmem_cache *s, char *buf)
+{
+ return sprintf(buf, "%d\n", s->reserved);
+}
+SLAB_ATTR_RO(reserved);
+
+#ifdef CONFIG_SLUB_DEBUG
+static ssize_t slabs_show(struct kmem_cache *s, char *buf)
+{
+ return show_slab_objects(s, buf, SO_ALL);
+}
+SLAB_ATTR_RO(slabs);
+
+static ssize_t total_objects_show(struct kmem_cache *s, char *buf)
+{
+ return show_slab_objects(s, buf, SO_ALL|SO_TOTAL);
+}
+SLAB_ATTR_RO(total_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 &= ~__CMPXCHG_DOUBLE;
+ 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)
+{
+ /*
+ * Tracing a merged cache is going to give confusing results
+ * as well as cause other issues like converting a mergeable
+ * cache into an umergeable one.
+ */
+ if (s->refcount > 1)
+ return -EINVAL;
+
+ s->flags &= ~SLAB_TRACE;
+ if (buf[0] == '1') {
+ s->flags &= ~__CMPXCHG_DOUBLE;
+ s->flags |= SLAB_TRACE;
+ }
+ return length;
+}
+SLAB_ATTR(trace);
+
+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 &= ~__CMPXCHG_DOUBLE;
+ s->flags |= SLAB_RED_ZONE;
+ }
+ calculate_sizes(s, -1);
+ 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 &= ~__CMPXCHG_DOUBLE;
+ s->flags |= SLAB_POISON;
+ }
+ calculate_sizes(s, -1);
+ 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 &= ~__CMPXCHG_DOUBLE;
+ s->flags |= SLAB_STORE_USER;
+ }
+ calculate_sizes(s, -1);
+ return length;
+}
+SLAB_ATTR(store_user);
+
+static ssize_t validate_show(struct kmem_cache *s, char *buf)
+{
+ return 0;
+}
+
+static ssize_t validate_store(struct kmem_cache *s,
+ const char *buf, size_t length)
+{
+ int ret = -EINVAL;
+
+ if (buf[0] == '1') {
+ ret = validate_slab_cache(s);
+ if (ret >= 0)
+ ret = length;
+ }
+ return ret;
+}
+SLAB_ATTR(validate);
+
+static ssize_t alloc_calls_show(struct kmem_cache *s, char *buf)
+{
+ if (!(s->flags & SLAB_STORE_USER))
+ return -ENOSYS;
+ return list_locations(s, buf, TRACK_ALLOC);
+}
+SLAB_ATTR_RO(alloc_calls);
+
+static ssize_t free_calls_show(struct kmem_cache *s, char *buf)
+{
+ if (!(s->flags & SLAB_STORE_USER))
+ return -ENOSYS;
+ return list_locations(s, buf, TRACK_FREE);
+}
+SLAB_ATTR_RO(free_calls);
+#endif /* CONFIG_SLUB_DEBUG */
+
+#ifdef CONFIG_FAILSLAB
+static ssize_t failslab_show(struct kmem_cache *s, char *buf)
+{
+ return sprintf(buf, "%d\n", !!(s->flags & SLAB_FAILSLAB));
+}
+
+static ssize_t failslab_store(struct kmem_cache *s, const char *buf,
+ size_t length)
+{
+ if (s->refcount > 1)
+ return -EINVAL;
+
+ s->flags &= ~SLAB_FAILSLAB;
+ if (buf[0] == '1')
+ s->flags |= SLAB_FAILSLAB;
+ return length;
+}
+SLAB_ATTR(failslab);
+#endif
+
+static ssize_t shrink_show(struct kmem_cache *s, char *buf)
+{
+ return 0;
+}
+
+static ssize_t shrink_store(struct kmem_cache *s,
+ const char *buf, size_t length)
+{
+ if (buf[0] == '1')
+ kmem_cache_shrink(s);
+ else
+ return -EINVAL;
+ return length;
+}
+SLAB_ATTR(shrink);
+
+#ifdef CONFIG_NUMA
+static ssize_t remote_node_defrag_ratio_show(struct kmem_cache *s, char *buf)
+{
+ return sprintf(buf, "%d\n", s->remote_node_defrag_ratio / 10);
+}
+
+static ssize_t remote_node_defrag_ratio_store(struct kmem_cache *s,
+ const char *buf, size_t length)
+{
+ unsigned long ratio;
+ int err;
+
+ err = kstrtoul(buf, 10, &ratio);
+ if (err)
+ return err;
+
+ if (ratio <= 100)
+ s->remote_node_defrag_ratio = ratio * 10;
+
+ return length;
+}
+SLAB_ATTR(remote_node_defrag_ratio);
+#endif
+
+#ifdef CONFIG_SLUB_STATS
+static int show_stat(struct kmem_cache *s, char *buf, enum stat_item si)
+{
+ unsigned long sum = 0;
+ int cpu;
+ int len;
+ int *data = kmalloc(nr_cpu_ids * sizeof(int), GFP_KERNEL);
+
+ if (!data)
+ return -ENOMEM;
+
+ for_each_online_cpu(cpu) {
+ unsigned x = per_cpu_ptr(s->cpu_slab, cpu)->stat[si];
+
+ data[cpu] = x;
+ sum += x;
+ }
+
+ len = sprintf(buf, "%lu", sum);
+
+#ifdef CONFIG_SMP
+ for_each_online_cpu(cpu) {
+ if (data[cpu] && len < PAGE_SIZE - 20)
+ len += sprintf(buf + len, " C%d=%u", cpu, data[cpu]);
+ }
+#endif
+ kfree(data);
+ return len + sprintf(buf + len, "\n");
+}
+
+static void clear_stat(struct kmem_cache *s, enum stat_item si)
+{
+ int cpu;
+
+ for_each_online_cpu(cpu)
+ per_cpu_ptr(s->cpu_slab, cpu)->stat[si] = 0;
+}
+
+#define STAT_ATTR(si, text) \
+static ssize_t text##_show(struct kmem_cache *s, char *buf) \
+{ \
+ return show_stat(s, buf, si); \
+} \
+static ssize_t text##_store(struct kmem_cache *s, \
+ const char *buf, size_t length) \
+{ \
+ if (buf[0] != '0') \
+ return -EINVAL; \
+ clear_stat(s, si); \
+ return length; \
+} \
+SLAB_ATTR(text); \
+
+STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath);
+STAT_ATTR(ALLOC_SLOWPATH, alloc_slowpath);
+STAT_ATTR(FREE_FASTPATH, free_fastpath);
+STAT_ATTR(FREE_SLOWPATH, free_slowpath);
+STAT_ATTR(FREE_FROZEN, free_frozen);
+STAT_ATTR(FREE_ADD_PARTIAL, free_add_partial);
+STAT_ATTR(FREE_REMOVE_PARTIAL, free_remove_partial);
+STAT_ATTR(ALLOC_FROM_PARTIAL, alloc_from_partial);
+STAT_ATTR(ALLOC_SLAB, alloc_slab);
+STAT_ATTR(ALLOC_REFILL, alloc_refill);
+STAT_ATTR(ALLOC_NODE_MISMATCH, alloc_node_mismatch);
+STAT_ATTR(FREE_SLAB, free_slab);
+STAT_ATTR(CPUSLAB_FLUSH, cpuslab_flush);
+STAT_ATTR(DEACTIVATE_FULL, deactivate_full);
+STAT_ATTR(DEACTIVATE_EMPTY, deactivate_empty);
+STAT_ATTR(DEACTIVATE_TO_HEAD, deactivate_to_head);
+STAT_ATTR(DEACTIVATE_TO_TAIL, deactivate_to_tail);
+STAT_ATTR(DEACTIVATE_REMOTE_FREES, deactivate_remote_frees);
+STAT_ATTR(DEACTIVATE_BYPASS, deactivate_bypass);
+STAT_ATTR(ORDER_FALLBACK, order_fallback);
+STAT_ATTR(CMPXCHG_DOUBLE_CPU_FAIL, cmpxchg_double_cpu_fail);
+STAT_ATTR(CMPXCHG_DOUBLE_FAIL, cmpxchg_double_fail);
+STAT_ATTR(CPU_PARTIAL_ALLOC, cpu_partial_alloc);
+STAT_ATTR(CPU_PARTIAL_FREE, cpu_partial_free);
+STAT_ATTR(CPU_PARTIAL_NODE, cpu_partial_node);
+STAT_ATTR(CPU_PARTIAL_DRAIN, cpu_partial_drain);
+#endif
+
+static struct attribute *slab_attrs[] = {
+ &slab_size_attr.attr,
+ &object_size_attr.attr,
+ &objs_per_slab_attr.attr,
+ &order_attr.attr,
+ &min_partial_attr.attr,
+ &cpu_partial_attr.attr,
+ &objects_attr.attr,
+ &objects_partial_attr.attr,
+ &partial_attr.attr,
+ &cpu_slabs_attr.attr,
+ &ctor_attr.attr,
+ &aliases_attr.attr,
+ &align_attr.attr,
+ &hwcache_align_attr.attr,
+ &reclaim_account_attr.attr,
+ &destroy_by_rcu_attr.attr,
+ &shrink_attr.attr,
+ &reserved_attr.attr,
+ &slabs_cpu_partial_attr.attr,
+#ifdef CONFIG_SLUB_DEBUG
+ &total_objects_attr.attr,
+ &slabs_attr.attr,
+ &sanity_checks_attr.attr,
+ &trace_attr.attr,
+ &red_zone_attr.attr,
+ &poison_attr.attr,
+ &store_user_attr.attr,
+ &validate_attr.attr,
+ &alloc_calls_attr.attr,
+ &free_calls_attr.attr,
+#endif
+#ifdef CONFIG_ZONE_DMA
+ &cache_dma_attr.attr,
+#endif
+#ifdef CONFIG_NUMA
+ &remote_node_defrag_ratio_attr.attr,
+#endif
+#ifdef CONFIG_SLUB_STATS
+ &alloc_fastpath_attr.attr,
+ &alloc_slowpath_attr.attr,
+ &free_fastpath_attr.attr,
+ &free_slowpath_attr.attr,
+ &free_frozen_attr.attr,
+ &free_add_partial_attr.attr,
+ &free_remove_partial_attr.attr,
+ &alloc_from_partial_attr.attr,
+ &alloc_slab_attr.attr,
+ &alloc_refill_attr.attr,
+ &alloc_node_mismatch_attr.attr,
+ &free_slab_attr.attr,
+ &cpuslab_flush_attr.attr,
+ &deactivate_full_attr.attr,
+ &deactivate_empty_attr.attr,
+ &deactivate_to_head_attr.attr,
+ &deactivate_to_tail_attr.attr,
+ &deactivate_remote_frees_attr.attr,
+ &deactivate_bypass_attr.attr,
+ &order_fallback_attr.attr,
+ &cmpxchg_double_fail_attr.attr,
+ &cmpxchg_double_cpu_fail_attr.attr,
+ &cpu_partial_alloc_attr.attr,
+ &cpu_partial_free_attr.attr,
+ &cpu_partial_node_attr.attr,
+ &cpu_partial_drain_attr.attr,
+#endif
+#ifdef CONFIG_FAILSLAB
+ &failslab_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);
+#ifdef CONFIG_MEMCG_KMEM
+ if (slab_state >= FULL && err >= 0 && is_root_cache(s)) {
+ struct kmem_cache *c;
+
+ mutex_lock(&slab_mutex);
+ if (s->max_attr_size < len)
+ s->max_attr_size = len;
+
+ /*
+ * This is a best effort propagation, so this function's return
+ * value will be determined by the parent cache only. This is
+ * basically because not all attributes will have a well
+ * defined semantics for rollbacks - most of the actions will
+ * have permanent effects.
+ *
+ * Returning the error value of any of the children that fail
+ * is not 100 % defined, in the sense that users seeing the
+ * error code won't be able to know anything about the state of
+ * the cache.
+ *
+ * Only returning the error code for the parent cache at least
+ * has well defined semantics. The cache being written to
+ * directly either failed or succeeded, in which case we loop
+ * through the descendants with best-effort propagation.
+ */
+ for_each_memcg_cache(c, s)
+ attribute->store(c, buf, len);
+ mutex_unlock(&slab_mutex);
+ }
+#endif
+ return err;
+}
+
+static void memcg_propagate_slab_attrs(struct kmem_cache *s)
+{
+#ifdef CONFIG_MEMCG_KMEM
+ int i;
+ char *buffer = NULL;
+ struct kmem_cache *root_cache;
+
+ if (is_root_cache(s))
+ return;
+
+ root_cache = s->memcg_params.root_cache;
+
+ /*
+ * This mean this cache had no attribute written. Therefore, no point
+ * in copying default values around
+ */
+ if (!root_cache->max_attr_size)
+ return;
+
+ for (i = 0; i < ARRAY_SIZE(slab_attrs); i++) {
+ char mbuf[64];
+ char *buf;
+ struct slab_attribute *attr = to_slab_attr(slab_attrs[i]);
+
+ if (!attr || !attr->store || !attr->show)
+ continue;
+
+ /*
+ * It is really bad that we have to allocate here, so we will
+ * do it only as a fallback. If we actually allocate, though,
+ * we can just use the allocated buffer until the end.
+ *
+ * Most of the slub attributes will tend to be very small in
+ * size, but sysfs allows buffers up to a page, so they can
+ * theoretically happen.
+ */
+ if (buffer)
+ buf = buffer;
+ else if (root_cache->max_attr_size < ARRAY_SIZE(mbuf))
+ buf = mbuf;
+ else {
+ buffer = (char *) get_zeroed_page(GFP_KERNEL);
+ if (WARN_ON(!buffer))
+ continue;
+ buf = buffer;
+ }
+
+ attr->show(root_cache, buf);
+ attr->store(s, buf, strlen(buf));
+ }
+
+ if (buffer)
+ free_page((unsigned long)buffer);
+#endif
+}
+
+static void kmem_cache_release(struct kobject *k)
+{
+ slab_kmem_cache_release(to_slab(k));
+}
+
+static const 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,
+ .release = kmem_cache_release,
+};
+
+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 const struct kset_uevent_ops slab_uevent_ops = {
+ .filter = uevent_filter,
+};
+
+static struct kset *slab_kset;
+
+static inline struct kset *cache_kset(struct kmem_cache *s)
+{
+#ifdef CONFIG_MEMCG_KMEM
+ if (!is_root_cache(s))
+ return s->memcg_params.root_cache->memcg_kset;
+#endif
+ return slab_kset;
+}
+
+#define ID_STR_LENGTH 64
+
+/* Create a unique string id for a slab cache:
+ *
+ * Format :[flags-]size
+ */
+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 (!(s->flags & SLAB_NOTRACK))
+ *p++ = 't';
+ 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 = 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_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);
+ }
+
+ s->kobj.kset = cache_kset(s);
+ err = kobject_init_and_add(&s->kobj, &slab_ktype, NULL, "%s", name);
+ if (err)
+ goto out_put_kobj;
+
+ err = sysfs_create_group(&s->kobj, &slab_attr_group);
+ if (err)
+ goto out_del_kobj;
+
+#ifdef CONFIG_MEMCG_KMEM
+ if (is_root_cache(s)) {
+ s->memcg_kset = kset_create_and_add("cgroup", NULL, &s->kobj);
+ if (!s->memcg_kset) {
+ err = -ENOMEM;
+ goto out_del_kobj;
+ }
+ }
+#endif
+
+ kobject_uevent(&s->kobj, KOBJ_ADD);
+ if (!unmergeable) {
+ /* Setup first alias */
+ sysfs_slab_alias(s, s->name);
+ }
+out:
+ if (!unmergeable)
+ kfree(name);
+ return err;
+out_del_kobj:
+ kobject_del(&s->kobj);
+out_put_kobj:
+ kobject_put(&s->kobj);
+ goto out;
+}
+
+void sysfs_slab_remove(struct kmem_cache *s)
+{
+ if (slab_state < FULL)
+ /*
+ * Sysfs has not been setup yet so no need to remove the
+ * cache from sysfs.
+ */
+ return;
+
+#ifdef CONFIG_MEMCG_KMEM
+ kset_unregister(s->memcg_kset);
+#endif
+ kobject_uevent(&s->kobj, KOBJ_REMOVE);
+ kobject_del(&s->kobj);
+ kobject_put(&s->kobj);
+}
+
+/*
+ * Need to buffer aliases during bootup until sysfs becomes
+ * available lest we lose that information.
+ */
+struct saved_alias {
+ struct kmem_cache *s;
+ const char *name;
+ struct saved_alias *next;
+};
+
+static struct saved_alias *alias_list;
+
+static int sysfs_slab_alias(struct kmem_cache *s, const char *name)
+{
+ struct saved_alias *al;
+
+ if (slab_state == FULL) {
+ /*
+ * If we have a leftover link then remove it.
+ */
+ sysfs_remove_link(&slab_kset->kobj, name);
+ return sysfs_create_link(&slab_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)
+{
+ struct kmem_cache *s;
+ int err;
+
+ mutex_lock(&slab_mutex);
+
+ slab_kset = kset_create_and_add("slab", &slab_uevent_ops, kernel_kobj);
+ if (!slab_kset) {
+ mutex_unlock(&slab_mutex);
+ pr_err("Cannot register slab subsystem.\n");
+ return -ENOSYS;
+ }
+
+ slab_state = FULL;
+
+ list_for_each_entry(s, &slab_caches, list) {
+ err = sysfs_slab_add(s);
+ if (err)
+ pr_err("SLUB: Unable to add boot slab %s to sysfs\n",
+ s->name);
+ }
+
+ while (alias_list) {
+ struct saved_alias *al = alias_list;
+
+ alias_list = alias_list->next;
+ err = sysfs_slab_alias(al->s, al->name);
+ if (err)
+ pr_err("SLUB: Unable to add boot slab alias %s to sysfs\n",
+ al->name);
+ kfree(al);
+ }
+
+ mutex_unlock(&slab_mutex);
+ resiliency_test();
+ return 0;
+}
+
+__initcall(slab_sysfs_init);
+#endif /* CONFIG_SYSFS */
+
+/*
+ * The /proc/slabinfo ABI
+ */
+#ifdef CONFIG_SLABINFO
+void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo)
+{
+ unsigned long nr_slabs = 0;
+ unsigned long nr_objs = 0;
+ unsigned long nr_free = 0;
+ int node;
+ struct kmem_cache_node *n;
+
+ for_each_kmem_cache_node(s, node, n) {
+ nr_slabs += node_nr_slabs(n);
+ nr_objs += node_nr_objs(n);
+ nr_free += count_partial(n, count_free);
+ }
+
+ sinfo->active_objs = nr_objs - nr_free;
+ sinfo->num_objs = nr_objs;
+ sinfo->active_slabs = nr_slabs;
+ sinfo->num_slabs = nr_slabs;
+ sinfo->objects_per_slab = oo_objects(s->oo);
+ sinfo->cache_order = oo_order(s->oo);
+}
+
+void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *s)
+{
+}
+
+ssize_t slabinfo_write(struct file *file, const char __user *buffer,
+ size_t count, loff_t *ppos)
+{
+ return -EIO;
+}
+#endif /* CONFIG_SLABINFO */
Code Review / kvmfornfv.git / blobdiff