3802 lines
89 KiB
C
3802 lines
89 KiB
C
/*
|
|
* SLUB: A slab allocator that limits cache line use instead of queuing
|
|
* objects in per cpu and per node lists.
|
|
*
|
|
* The allocator synchronizes using per slab locks and only
|
|
* uses a centralized lock to manage a pool of partial slabs.
|
|
*
|
|
* (C) 2007 SGI, Christoph Lameter <clameter@sgi.com>
|
|
*/
|
|
|
|
#include <linux/mm.h>
|
|
#include <linux/module.h>
|
|
#include <linux/bit_spinlock.h>
|
|
#include <linux/interrupt.h>
|
|
#include <linux/bitops.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/seq_file.h>
|
|
#include <linux/cpu.h>
|
|
#include <linux/cpuset.h>
|
|
#include <linux/mempolicy.h>
|
|
#include <linux/ctype.h>
|
|
#include <linux/kallsyms.h>
|
|
|
|
/*
|
|
* Lock order:
|
|
* 1. slab_lock(page)
|
|
* 2. slab->list_lock
|
|
*
|
|
* The slab_lock protects operations on the object of a particular
|
|
* slab and its metadata in the page struct. If the slab lock
|
|
* has been taken then no allocations nor frees can be performed
|
|
* on the objects in the slab nor can the slab be added or removed
|
|
* from the partial or full lists since this would mean modifying
|
|
* the page_struct of the slab.
|
|
*
|
|
* The list_lock protects the partial and full list on each node and
|
|
* the partial slab counter. If taken then no new slabs may be added or
|
|
* removed from the lists nor make the number of partial slabs be modified.
|
|
* (Note that the total number of slabs is an atomic value that may be
|
|
* modified without taking the list lock).
|
|
*
|
|
* The list_lock is a centralized lock and thus we avoid taking it as
|
|
* much as possible. As long as SLUB does not have to handle partial
|
|
* slabs, operations can continue without any centralized lock. F.e.
|
|
* allocating a long series of objects that fill up slabs does not require
|
|
* the list lock.
|
|
*
|
|
* The lock order is sometimes inverted when we are trying to get a slab
|
|
* off a list. We take the list_lock and then look for a page on the list
|
|
* to use. While we do that objects in the slabs may be freed. We can
|
|
* only operate on the slab if we have also taken the slab_lock. So we use
|
|
* a slab_trylock() on the slab. If trylock was successful then no frees
|
|
* can occur anymore and we can use the slab for allocations etc. If the
|
|
* slab_trylock() does not succeed then frees are in progress in the slab and
|
|
* we must stay away from it for a while since we may cause a bouncing
|
|
* cacheline if we try to acquire the lock. So go onto the next slab.
|
|
* If all pages are busy then we may allocate a new slab instead of reusing
|
|
* a partial slab. A new slab has noone operating on it and thus there is
|
|
* no danger of cacheline contention.
|
|
*
|
|
* Interrupts are disabled during allocation and deallocation in order to
|
|
* make the slab allocator safe to use in the context of an irq. In addition
|
|
* interrupts are disabled to ensure that the processor does not change
|
|
* while handling per_cpu slabs, due to kernel preemption.
|
|
*
|
|
* SLUB assigns one slab for allocation to each processor.
|
|
* Allocations only occur from these slabs called cpu slabs.
|
|
*
|
|
* Slabs with free elements are kept on a partial list 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
|
|
* lockless_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.
|
|
*/
|
|
|
|
#define FROZEN (1 << PG_active)
|
|
|
|
#ifdef CONFIG_SLUB_DEBUG
|
|
#define SLABDEBUG (1 << PG_error)
|
|
#else
|
|
#define SLABDEBUG 0
|
|
#endif
|
|
|
|
static inline int SlabFrozen(struct page *page)
|
|
{
|
|
return page->flags & FROZEN;
|
|
}
|
|
|
|
static inline void SetSlabFrozen(struct page *page)
|
|
{
|
|
page->flags |= FROZEN;
|
|
}
|
|
|
|
static inline void ClearSlabFrozen(struct page *page)
|
|
{
|
|
page->flags &= ~FROZEN;
|
|
}
|
|
|
|
static inline int SlabDebug(struct page *page)
|
|
{
|
|
return page->flags & SLABDEBUG;
|
|
}
|
|
|
|
static inline void SetSlabDebug(struct page *page)
|
|
{
|
|
page->flags |= SLABDEBUG;
|
|
}
|
|
|
|
static inline void ClearSlabDebug(struct page *page)
|
|
{
|
|
page->flags &= ~SLABDEBUG;
|
|
}
|
|
|
|
/*
|
|
* Issues still to be resolved:
|
|
*
|
|
* - The per cpu array is updated for each new slab and and is a remote
|
|
* cacheline for most nodes. This could become a bouncing cacheline given
|
|
* enough frequent updates. There are 16 pointers in a cacheline, so at
|
|
* max 16 cpus could compete for the cacheline which may be okay.
|
|
*
|
|
* - 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
|
|
|
|
#if PAGE_SHIFT <= 12
|
|
|
|
/*
|
|
* Small page size. Make sure that we do not fragment memory
|
|
*/
|
|
#define DEFAULT_MAX_ORDER 1
|
|
#define DEFAULT_MIN_OBJECTS 4
|
|
|
|
#else
|
|
|
|
/*
|
|
* Large page machines are customarily able to handle larger
|
|
* page orders.
|
|
*/
|
|
#define DEFAULT_MAX_ORDER 2
|
|
#define DEFAULT_MIN_OBJECTS 8
|
|
|
|
#endif
|
|
|
|
/*
|
|
* 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 2
|
|
|
|
/*
|
|
* 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 the.
|
|
*/
|
|
#define MAX_PARTIAL 10
|
|
|
|
#define DEBUG_DEFAULT_FLAGS (SLAB_DEBUG_FREE | SLAB_RED_ZONE | \
|
|
SLAB_POISON | SLAB_STORE_USER)
|
|
|
|
/*
|
|
* Set of flags that will prevent slab merging
|
|
*/
|
|
#define SLUB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
|
|
SLAB_TRACE | SLAB_DESTROY_BY_RCU)
|
|
|
|
#define SLUB_MERGE_SAME (SLAB_DEBUG_FREE | SLAB_RECLAIM_ACCOUNT | \
|
|
SLAB_CACHE_DMA)
|
|
|
|
#ifndef ARCH_KMALLOC_MINALIGN
|
|
#define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)
|
|
#endif
|
|
|
|
#ifndef ARCH_SLAB_MINALIGN
|
|
#define ARCH_SLAB_MINALIGN __alignof__(unsigned long long)
|
|
#endif
|
|
|
|
/*
|
|
* The page->inuse field is 16 bit thus we have this limitation
|
|
*/
|
|
#define MAX_OBJECTS_PER_SLAB 65535
|
|
|
|
/* Internal SLUB flags */
|
|
#define __OBJECT_POISON 0x80000000 /* Poison object */
|
|
|
|
/* Not all arches define cache_line_size */
|
|
#ifndef cache_line_size
|
|
#define cache_line_size() L1_CACHE_BYTES
|
|
#endif
|
|
|
|
static int kmem_size = sizeof(struct kmem_cache);
|
|
|
|
#ifdef CONFIG_SMP
|
|
static struct notifier_block slab_notifier;
|
|
#endif
|
|
|
|
static enum {
|
|
DOWN, /* No slab functionality available */
|
|
PARTIAL, /* kmem_cache_open() works but kmalloc does not */
|
|
UP, /* Everything works but does not show up in sysfs */
|
|
SYSFS /* Sysfs up */
|
|
} slab_state = DOWN;
|
|
|
|
/* A list of all slab caches on the system */
|
|
static DECLARE_RWSEM(slub_lock);
|
|
static LIST_HEAD(slab_caches);
|
|
|
|
/*
|
|
* Tracking user of a slab.
|
|
*/
|
|
struct track {
|
|
void *addr; /* Called from address */
|
|
int cpu; /* Was running on cpu */
|
|
int pid; /* Pid context */
|
|
unsigned long when; /* When did the operation occur */
|
|
};
|
|
|
|
enum track_item { TRACK_ALLOC, TRACK_FREE };
|
|
|
|
#if defined(CONFIG_SYSFS) && defined(CONFIG_SLUB_DEBUG)
|
|
static int sysfs_slab_add(struct kmem_cache *);
|
|
static int sysfs_slab_alias(struct kmem_cache *, const char *);
|
|
static void sysfs_slab_remove(struct kmem_cache *);
|
|
#else
|
|
static 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 sysfs_slab_remove(struct kmem_cache *s) {}
|
|
#endif
|
|
|
|
/********************************************************************
|
|
* Core slab cache functions
|
|
*******************************************************************/
|
|
|
|
int slab_is_available(void)
|
|
{
|
|
return slab_state >= UP;
|
|
}
|
|
|
|
static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node)
|
|
{
|
|
#ifdef CONFIG_NUMA
|
|
return s->node[node];
|
|
#else
|
|
return &s->local_node;
|
|
#endif
|
|
}
|
|
|
|
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 + s->objects * s->size ||
|
|
(object - base) % s->size) {
|
|
return 0;
|
|
}
|
|
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* Slow version of get and set free pointer.
|
|
*
|
|
* This version requires touching the cache lines of kmem_cache which
|
|
* we avoid to do in the fast alloc free paths. There we obtain the offset
|
|
* from the page struct.
|
|
*/
|
|
static inline void *get_freepointer(struct kmem_cache *s, void *object)
|
|
{
|
|
return *(void **)(object + s->offset);
|
|
}
|
|
|
|
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) \
|
|
for (__p = (__addr); __p < (__addr) + (__s)->objects * (__s)->size;\
|
|
__p += (__s)->size)
|
|
|
|
/* Scan freelist */
|
|
#define for_each_free_object(__p, __s, __free) \
|
|
for (__p = (__free); __p; __p = get_freepointer((__s), __p))
|
|
|
|
/* 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;
|
|
}
|
|
|
|
#ifdef CONFIG_SLUB_DEBUG
|
|
/*
|
|
* 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;
|
|
|
|
/*
|
|
* Object debugging
|
|
*/
|
|
static void print_section(char *text, u8 *addr, unsigned int length)
|
|
{
|
|
int i, offset;
|
|
int newline = 1;
|
|
char ascii[17];
|
|
|
|
ascii[16] = 0;
|
|
|
|
for (i = 0; i < length; i++) {
|
|
if (newline) {
|
|
printk(KERN_ERR "%8s 0x%p: ", text, addr + i);
|
|
newline = 0;
|
|
}
|
|
printk(" %02x", addr[i]);
|
|
offset = i % 16;
|
|
ascii[offset] = isgraph(addr[i]) ? addr[i] : '.';
|
|
if (offset == 15) {
|
|
printk(" %s\n",ascii);
|
|
newline = 1;
|
|
}
|
|
}
|
|
if (!newline) {
|
|
i %= 16;
|
|
while (i < 16) {
|
|
printk(" ");
|
|
ascii[i] = ' ';
|
|
i++;
|
|
}
|
|
printk(" %s\n", ascii);
|
|
}
|
|
}
|
|
|
|
static struct track *get_track(struct kmem_cache *s, void *object,
|
|
enum track_item alloc)
|
|
{
|
|
struct track *p;
|
|
|
|
if (s->offset)
|
|
p = object + s->offset + sizeof(void *);
|
|
else
|
|
p = object + s->inuse;
|
|
|
|
return p + alloc;
|
|
}
|
|
|
|
static void set_track(struct kmem_cache *s, void *object,
|
|
enum track_item alloc, void *addr)
|
|
{
|
|
struct track *p;
|
|
|
|
if (s->offset)
|
|
p = object + s->offset + sizeof(void *);
|
|
else
|
|
p = object + s->inuse;
|
|
|
|
p += alloc;
|
|
if (addr) {
|
|
p->addr = addr;
|
|
p->cpu = smp_processor_id();
|
|
p->pid = current ? current->pid : -1;
|
|
p->when = jiffies;
|
|
} else
|
|
memset(p, 0, sizeof(struct track));
|
|
}
|
|
|
|
static void init_tracking(struct kmem_cache *s, void *object)
|
|
{
|
|
if (!(s->flags & SLAB_STORE_USER))
|
|
return;
|
|
|
|
set_track(s, object, TRACK_FREE, NULL);
|
|
set_track(s, object, TRACK_ALLOC, NULL);
|
|
}
|
|
|
|
static void print_track(const char *s, struct track *t)
|
|
{
|
|
if (!t->addr)
|
|
return;
|
|
|
|
printk(KERN_ERR "INFO: %s in ", s);
|
|
__print_symbol("%s", (unsigned long)t->addr);
|
|
printk(" age=%lu cpu=%u pid=%d\n", jiffies - t->when, t->cpu, t->pid);
|
|
}
|
|
|
|
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)
|
|
{
|
|
printk(KERN_ERR "INFO: Slab 0x%p used=%u fp=0x%p flags=0x%04lx\n",
|
|
page, page->inuse, page->freelist, page->flags);
|
|
|
|
}
|
|
|
|
static void slab_bug(struct kmem_cache *s, char *fmt, ...)
|
|
{
|
|
va_list args;
|
|
char buf[100];
|
|
|
|
va_start(args, fmt);
|
|
vsnprintf(buf, sizeof(buf), fmt, args);
|
|
va_end(args);
|
|
printk(KERN_ERR "========================================"
|
|
"=====================================\n");
|
|
printk(KERN_ERR "BUG %s: %s\n", s->name, buf);
|
|
printk(KERN_ERR "----------------------------------------"
|
|
"-------------------------------------\n\n");
|
|
}
|
|
|
|
static void slab_fix(struct kmem_cache *s, char *fmt, ...)
|
|
{
|
|
va_list args;
|
|
char buf[100];
|
|
|
|
va_start(args, fmt);
|
|
vsnprintf(buf, sizeof(buf), fmt, args);
|
|
va_end(args);
|
|
printk(KERN_ERR "FIX %s: %s\n", s->name, buf);
|
|
}
|
|
|
|
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);
|
|
|
|
printk(KERN_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(s->objsize, 128));
|
|
|
|
if (s->flags & SLAB_RED_ZONE)
|
|
print_section("Redzone", p + s->objsize,
|
|
s->inuse - s->objsize);
|
|
|
|
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();
|
|
}
|
|
|
|
static void object_err(struct kmem_cache *s, struct page *page,
|
|
u8 *object, char *reason)
|
|
{
|
|
slab_bug(s, reason);
|
|
print_trailer(s, page, object);
|
|
}
|
|
|
|
static void slab_err(struct kmem_cache *s, struct page *page, char *fmt, ...)
|
|
{
|
|
va_list args;
|
|
char buf[100];
|
|
|
|
va_start(args, fmt);
|
|
vsnprintf(buf, sizeof(buf), fmt, args);
|
|
va_end(args);
|
|
slab_bug(s, fmt);
|
|
print_page_info(page);
|
|
dump_stack();
|
|
}
|
|
|
|
static void init_object(struct kmem_cache *s, void *object, int active)
|
|
{
|
|
u8 *p = object;
|
|
|
|
if (s->flags & __OBJECT_POISON) {
|
|
memset(p, POISON_FREE, s->objsize - 1);
|
|
p[s->objsize -1] = POISON_END;
|
|
}
|
|
|
|
if (s->flags & SLAB_RED_ZONE)
|
|
memset(p + s->objsize,
|
|
active ? SLUB_RED_ACTIVE : SLUB_RED_INACTIVE,
|
|
s->inuse - s->objsize);
|
|
}
|
|
|
|
static u8 *check_bytes(u8 *start, unsigned int value, unsigned int bytes)
|
|
{
|
|
while (bytes) {
|
|
if (*start != (u8)value)
|
|
return start;
|
|
start++;
|
|
bytes--;
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
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;
|
|
|
|
fault = check_bytes(start, value, bytes);
|
|
if (!fault)
|
|
return 1;
|
|
|
|
end = start + bytes;
|
|
while (end > fault && end[-1] == value)
|
|
end--;
|
|
|
|
slab_bug(s, "%s overwritten", what);
|
|
printk(KERN_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->objsize
|
|
* Padding to reach word boundary. This is also used for Redzoning.
|
|
* Padding is extended by another word if Redzoning is enabled and
|
|
* objsize == inuse.
|
|
*
|
|
* We fill with 0xbb (RED_INACTIVE) for inactive objects and with
|
|
* 0xcc (RED_ACTIVE) for objects in use.
|
|
*
|
|
* object + s->inuse
|
|
* 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 debuggin 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 objsize 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);
|
|
}
|
|
|
|
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);
|
|
end = start + (PAGE_SIZE << s->order);
|
|
length = s->objects * s->size;
|
|
remainder = end - (start + length);
|
|
if (!remainder)
|
|
return 1;
|
|
|
|
fault = check_bytes(start + length, POISON_INUSE, remainder);
|
|
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", start, length);
|
|
|
|
restore_bytes(s, "slab padding", POISON_INUSE, start, end);
|
|
return 0;
|
|
}
|
|
|
|
static int check_object(struct kmem_cache *s, struct page *page,
|
|
void *object, int active)
|
|
{
|
|
u8 *p = object;
|
|
u8 *endobject = object + s->objsize;
|
|
|
|
if (s->flags & SLAB_RED_ZONE) {
|
|
unsigned int red =
|
|
active ? SLUB_RED_ACTIVE : SLUB_RED_INACTIVE;
|
|
|
|
if (!check_bytes_and_report(s, page, object, "Redzone",
|
|
endobject, red, s->inuse - s->objsize))
|
|
return 0;
|
|
} else {
|
|
if ((s->flags & SLAB_POISON) && s->objsize < s->inuse)
|
|
check_bytes_and_report(s, page, p, "Alignment padding", endobject,
|
|
POISON_INUSE, s->inuse - s->objsize);
|
|
}
|
|
|
|
if (s->flags & SLAB_POISON) {
|
|
if (!active && (s->flags & __OBJECT_POISON) &&
|
|
(!check_bytes_and_report(s, page, p, "Poison", p,
|
|
POISON_FREE, s->objsize - 1) ||
|
|
!check_bytes_and_report(s, page, p, "Poison",
|
|
p + s->objsize -1, POISON_END, 1)))
|
|
return 0;
|
|
/*
|
|
* check_pad_bytes cleans up on its own.
|
|
*/
|
|
check_pad_bytes(s, page, p);
|
|
}
|
|
|
|
if (!s->offset && active)
|
|
/*
|
|
* Object and freepointer overlap. Cannot check
|
|
* freepointer while object is allocated.
|
|
*/
|
|
return 1;
|
|
|
|
/* Check free pointer validity */
|
|
if (!check_valid_pointer(s, page, get_freepointer(s, p))) {
|
|
object_err(s, page, p, "Freepointer corrupt");
|
|
/*
|
|
* No choice but to zap it and thus loose the remainder
|
|
* of the free objects in this slab. May cause
|
|
* another error because the object count is now wrong.
|
|
*/
|
|
set_freepointer(s, p, NULL);
|
|
return 0;
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
static int check_slab(struct kmem_cache *s, struct page *page)
|
|
{
|
|
VM_BUG_ON(!irqs_disabled());
|
|
|
|
if (!PageSlab(page)) {
|
|
slab_err(s, page, "Not a valid slab page");
|
|
return 0;
|
|
}
|
|
if (page->offset * sizeof(void *) != s->offset) {
|
|
slab_err(s, page, "Corrupted offset %lu",
|
|
(unsigned long)(page->offset * sizeof(void *)));
|
|
return 0;
|
|
}
|
|
if (page->inuse > s->objects) {
|
|
slab_err(s, page, "inuse %u > max %u",
|
|
s->name, page->inuse, s->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 = page->freelist;
|
|
void *object = NULL;
|
|
|
|
while (fp && nr <= s->objects) {
|
|
if (fp == search)
|
|
return 1;
|
|
if (!check_valid_pointer(s, page, fp)) {
|
|
if (object) {
|
|
object_err(s, page, object,
|
|
"Freechain corrupt");
|
|
set_freepointer(s, object, NULL);
|
|
break;
|
|
} else {
|
|
slab_err(s, page, "Freepointer corrupt");
|
|
page->freelist = NULL;
|
|
page->inuse = s->objects;
|
|
slab_fix(s, "Freelist cleared");
|
|
return 0;
|
|
}
|
|
break;
|
|
}
|
|
object = fp;
|
|
fp = get_freepointer(s, object);
|
|
nr++;
|
|
}
|
|
|
|
if (page->inuse != s->objects - nr) {
|
|
slab_err(s, page, "Wrong object count. Counter is %d but "
|
|
"counted were %d", page->inuse, s->objects - nr);
|
|
page->inuse = s->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) {
|
|
printk(KERN_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->objsize);
|
|
|
|
dump_stack();
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Tracking of fully allocated slabs for debugging purposes.
|
|
*/
|
|
static void add_full(struct kmem_cache_node *n, struct page *page)
|
|
{
|
|
spin_lock(&n->list_lock);
|
|
list_add(&page->lru, &n->full);
|
|
spin_unlock(&n->list_lock);
|
|
}
|
|
|
|
static void remove_full(struct kmem_cache *s, struct page *page)
|
|
{
|
|
struct kmem_cache_node *n;
|
|
|
|
if (!(s->flags & SLAB_STORE_USER))
|
|
return;
|
|
|
|
n = get_node(s, page_to_nid(page));
|
|
|
|
spin_lock(&n->list_lock);
|
|
list_del(&page->lru);
|
|
spin_unlock(&n->list_lock);
|
|
}
|
|
|
|
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, 0);
|
|
init_tracking(s, object);
|
|
}
|
|
|
|
static int alloc_debug_processing(struct kmem_cache *s, struct page *page,
|
|
void *object, void *addr)
|
|
{
|
|
if (!check_slab(s, page))
|
|
goto bad;
|
|
|
|
if (object && !on_freelist(s, page, object)) {
|
|
object_err(s, page, object, "Object already allocated");
|
|
goto bad;
|
|
}
|
|
|
|
if (!check_valid_pointer(s, page, object)) {
|
|
object_err(s, page, object, "Freelist Pointer check fails");
|
|
goto bad;
|
|
}
|
|
|
|
if (object && !check_object(s, page, object, 0))
|
|
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, 1);
|
|
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 = s->objects;
|
|
page->freelist = NULL;
|
|
/* Fix up fields that may be corrupted */
|
|
page->offset = s->offset / sizeof(void *);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int free_debug_processing(struct kmem_cache *s, struct page *page,
|
|
void *object, void *addr)
|
|
{
|
|
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, 1))
|
|
return 0;
|
|
|
|
if (unlikely(s != page->slab)) {
|
|
if (!PageSlab(page))
|
|
slab_err(s, page, "Attempt to free object(0x%p) "
|
|
"outside of slab", object);
|
|
else
|
|
if (!page->slab) {
|
|
printk(KERN_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;
|
|
}
|
|
|
|
/* Special debug activities for freeing objects */
|
|
if (!SlabFrozen(page) && !page->freelist)
|
|
remove_full(s, page);
|
|
if (s->flags & SLAB_STORE_USER)
|
|
set_track(s, object, TRACK_FREE, addr);
|
|
trace(s, page, object, 0);
|
|
init_object(s, object, 0);
|
|
return 1;
|
|
|
|
fail:
|
|
slab_fix(s, "Object at 0x%p not freed", object);
|
|
return 0;
|
|
}
|
|
|
|
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;
|
|
default:
|
|
printk(KERN_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);
|
|
|
|
static void kmem_cache_open_debug_check(struct kmem_cache *s)
|
|
{
|
|
/*
|
|
* The page->offset field is only 16 bit wide. This is an offset
|
|
* in units of words from the beginning of an object. If the slab
|
|
* size is bigger then we cannot move the free pointer behind the
|
|
* object anymore.
|
|
*
|
|
* On 32 bit platforms the limit is 256k. On 64bit platforms
|
|
* the limit is 512k.
|
|
*
|
|
* Debugging or ctor may create a need to move the free
|
|
* pointer. Fail if this happens.
|
|
*/
|
|
if (s->objsize >= 65535 * sizeof(void *)) {
|
|
BUG_ON(s->flags & (SLAB_RED_ZONE | SLAB_POISON |
|
|
SLAB_STORE_USER | SLAB_DESTROY_BY_RCU));
|
|
BUG_ON(s->ctor);
|
|
}
|
|
else
|
|
/*
|
|
* Enable debugging if selected on the kernel commandline.
|
|
*/
|
|
if (slub_debug && (!slub_debug_slabs ||
|
|
strncmp(slub_debug_slabs, s->name,
|
|
strlen(slub_debug_slabs)) == 0))
|
|
s->flags |= slub_debug;
|
|
}
|
|
#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, void *addr) { return 0; }
|
|
|
|
static inline int free_debug_processing(struct kmem_cache *s,
|
|
struct page *page, void *object, void *addr) { return 0; }
|
|
|
|
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, int active) { return 1; }
|
|
static inline void add_full(struct kmem_cache_node *n, struct page *page) {}
|
|
static inline void kmem_cache_open_debug_check(struct kmem_cache *s) {}
|
|
#define slub_debug 0
|
|
#endif
|
|
/*
|
|
* Slab allocation and freeing
|
|
*/
|
|
static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
|
|
{
|
|
struct page * page;
|
|
int pages = 1 << s->order;
|
|
|
|
if (s->order)
|
|
flags |= __GFP_COMP;
|
|
|
|
if (s->flags & SLAB_CACHE_DMA)
|
|
flags |= SLUB_DMA;
|
|
|
|
if (node == -1)
|
|
page = alloc_pages(flags, s->order);
|
|
else
|
|
page = alloc_pages_node(node, flags, s->order);
|
|
|
|
if (!page)
|
|
return NULL;
|
|
|
|
mod_zone_page_state(page_zone(page),
|
|
(s->flags & SLAB_RECLAIM_ACCOUNT) ?
|
|
NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
|
|
pages);
|
|
|
|
return page;
|
|
}
|
|
|
|
static void setup_object(struct kmem_cache *s, struct page *page,
|
|
void *object)
|
|
{
|
|
setup_object_debug(s, page, object);
|
|
if (unlikely(s->ctor))
|
|
s->ctor(object, s, 0);
|
|
}
|
|
|
|
static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node)
|
|
{
|
|
struct page *page;
|
|
struct kmem_cache_node *n;
|
|
void *start;
|
|
void *end;
|
|
void *last;
|
|
void *p;
|
|
|
|
BUG_ON(flags & ~(GFP_DMA | __GFP_ZERO | GFP_LEVEL_MASK));
|
|
|
|
if (flags & __GFP_WAIT)
|
|
local_irq_enable();
|
|
|
|
page = allocate_slab(s, flags & GFP_LEVEL_MASK, node);
|
|
if (!page)
|
|
goto out;
|
|
|
|
n = get_node(s, page_to_nid(page));
|
|
if (n)
|
|
atomic_long_inc(&n->nr_slabs);
|
|
page->offset = s->offset / sizeof(void *);
|
|
page->slab = s;
|
|
page->flags |= 1 << PG_slab;
|
|
if (s->flags & (SLAB_DEBUG_FREE | SLAB_RED_ZONE | SLAB_POISON |
|
|
SLAB_STORE_USER | SLAB_TRACE))
|
|
SetSlabDebug(page);
|
|
|
|
start = page_address(page);
|
|
end = start + s->objects * s->size;
|
|
|
|
if (unlikely(s->flags & SLAB_POISON))
|
|
memset(start, POISON_INUSE, PAGE_SIZE << s->order);
|
|
|
|
last = start;
|
|
for_each_object(p, s, start) {
|
|
setup_object(s, page, last);
|
|
set_freepointer(s, last, p);
|
|
last = p;
|
|
}
|
|
setup_object(s, page, last);
|
|
set_freepointer(s, last, NULL);
|
|
|
|
page->freelist = start;
|
|
page->lockless_freelist = NULL;
|
|
page->inuse = 0;
|
|
out:
|
|
if (flags & __GFP_WAIT)
|
|
local_irq_disable();
|
|
return page;
|
|
}
|
|
|
|
static void __free_slab(struct kmem_cache *s, struct page *page)
|
|
{
|
|
int pages = 1 << s->order;
|
|
|
|
if (unlikely(SlabDebug(page))) {
|
|
void *p;
|
|
|
|
slab_pad_check(s, page);
|
|
for_each_object(p, s, page_address(page))
|
|
check_object(s, page, p, 0);
|
|
}
|
|
|
|
mod_zone_page_state(page_zone(page),
|
|
(s->flags & SLAB_RECLAIM_ACCOUNT) ?
|
|
NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
|
|
- pages);
|
|
|
|
page->mapping = NULL;
|
|
__free_pages(page, s->order);
|
|
}
|
|
|
|
static void rcu_free_slab(struct rcu_head *h)
|
|
{
|
|
struct page *page;
|
|
|
|
page = container_of((struct list_head *)h, struct page, lru);
|
|
__free_slab(page->slab, page);
|
|
}
|
|
|
|
static void free_slab(struct kmem_cache *s, struct page *page)
|
|
{
|
|
if (unlikely(s->flags & SLAB_DESTROY_BY_RCU)) {
|
|
/*
|
|
* RCU free overloads the RCU head over the LRU
|
|
*/
|
|
struct rcu_head *head = (void *)&page->lru;
|
|
|
|
call_rcu(head, rcu_free_slab);
|
|
} else
|
|
__free_slab(s, page);
|
|
}
|
|
|
|
static void discard_slab(struct kmem_cache *s, struct page *page)
|
|
{
|
|
struct kmem_cache_node *n = get_node(s, page_to_nid(page));
|
|
|
|
atomic_long_dec(&n->nr_slabs);
|
|
reset_page_mapcount(page);
|
|
ClearSlabDebug(page);
|
|
__ClearPageSlab(page);
|
|
free_slab(s, page);
|
|
}
|
|
|
|
/*
|
|
* Per slab locking using the pagelock
|
|
*/
|
|
static __always_inline void slab_lock(struct page *page)
|
|
{
|
|
bit_spin_lock(PG_locked, &page->flags);
|
|
}
|
|
|
|
static __always_inline void slab_unlock(struct page *page)
|
|
{
|
|
bit_spin_unlock(PG_locked, &page->flags);
|
|
}
|
|
|
|
static __always_inline int slab_trylock(struct page *page)
|
|
{
|
|
int rc = 1;
|
|
|
|
rc = bit_spin_trylock(PG_locked, &page->flags);
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
* Management of partially allocated slabs
|
|
*/
|
|
static void add_partial_tail(struct kmem_cache_node *n, struct page *page)
|
|
{
|
|
spin_lock(&n->list_lock);
|
|
n->nr_partial++;
|
|
list_add_tail(&page->lru, &n->partial);
|
|
spin_unlock(&n->list_lock);
|
|
}
|
|
|
|
static void add_partial(struct kmem_cache_node *n, struct page *page)
|
|
{
|
|
spin_lock(&n->list_lock);
|
|
n->nr_partial++;
|
|
list_add(&page->lru, &n->partial);
|
|
spin_unlock(&n->list_lock);
|
|
}
|
|
|
|
static void remove_partial(struct kmem_cache *s,
|
|
struct page *page)
|
|
{
|
|
struct kmem_cache_node *n = get_node(s, page_to_nid(page));
|
|
|
|
spin_lock(&n->list_lock);
|
|
list_del(&page->lru);
|
|
n->nr_partial--;
|
|
spin_unlock(&n->list_lock);
|
|
}
|
|
|
|
/*
|
|
* Lock slab and remove from the partial list.
|
|
*
|
|
* Must hold list_lock.
|
|
*/
|
|
static inline int lock_and_freeze_slab(struct kmem_cache_node *n, struct page *page)
|
|
{
|
|
if (slab_trylock(page)) {
|
|
list_del(&page->lru);
|
|
n->nr_partial--;
|
|
SetSlabFrozen(page);
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Try to allocate a partial slab from a specific node.
|
|
*/
|
|
static struct page *get_partial_node(struct kmem_cache_node *n)
|
|
{
|
|
struct page *page;
|
|
|
|
/*
|
|
* Racy check. If we mistakenly see no partial slabs then we
|
|
* just allocate an empty slab. If we mistakenly try to get a
|
|
* partial slab and there is none available then get_partials()
|
|
* will return NULL.
|
|
*/
|
|
if (!n || !n->nr_partial)
|
|
return NULL;
|
|
|
|
spin_lock(&n->list_lock);
|
|
list_for_each_entry(page, &n->partial, lru)
|
|
if (lock_and_freeze_slab(n, page))
|
|
goto out;
|
|
page = NULL;
|
|
out:
|
|
spin_unlock(&n->list_lock);
|
|
return page;
|
|
}
|
|
|
|
/*
|
|
* Get a page from somewhere. Search in increasing NUMA distances.
|
|
*/
|
|
static struct page *get_any_partial(struct kmem_cache *s, gfp_t flags)
|
|
{
|
|
#ifdef CONFIG_NUMA
|
|
struct zonelist *zonelist;
|
|
struct zone **z;
|
|
struct page *page;
|
|
|
|
/*
|
|
* The defrag ratio allows 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/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->defrag_ratio || get_cycles() % 1024 > s->defrag_ratio)
|
|
return NULL;
|
|
|
|
zonelist = &NODE_DATA(slab_node(current->mempolicy))
|
|
->node_zonelists[gfp_zone(flags)];
|
|
for (z = zonelist->zones; *z; z++) {
|
|
struct kmem_cache_node *n;
|
|
|
|
n = get_node(s, zone_to_nid(*z));
|
|
|
|
if (n && cpuset_zone_allowed_hardwall(*z, flags) &&
|
|
n->nr_partial > MIN_PARTIAL) {
|
|
page = get_partial_node(n);
|
|
if (page)
|
|
return page;
|
|
}
|
|
}
|
|
#endif
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* Get a partial page, lock it and return it.
|
|
*/
|
|
static struct page *get_partial(struct kmem_cache *s, gfp_t flags, int node)
|
|
{
|
|
struct page *page;
|
|
int searchnode = (node == -1) ? numa_node_id() : node;
|
|
|
|
page = get_partial_node(get_node(s, searchnode));
|
|
if (page || (flags & __GFP_THISNODE))
|
|
return page;
|
|
|
|
return get_any_partial(s, flags);
|
|
}
|
|
|
|
/*
|
|
* Move a page back to the lists.
|
|
*
|
|
* Must be called with the slab lock held.
|
|
*
|
|
* On exit the slab lock will have been dropped.
|
|
*/
|
|
static void unfreeze_slab(struct kmem_cache *s, struct page *page)
|
|
{
|
|
struct kmem_cache_node *n = get_node(s, page_to_nid(page));
|
|
|
|
ClearSlabFrozen(page);
|
|
if (page->inuse) {
|
|
|
|
if (page->freelist)
|
|
add_partial(n, page);
|
|
else if (SlabDebug(page) && (s->flags & SLAB_STORE_USER))
|
|
add_full(n, page);
|
|
slab_unlock(page);
|
|
|
|
} else {
|
|
if (n->nr_partial < MIN_PARTIAL) {
|
|
/*
|
|
* Adding an empty slab to the partial slabs in order
|
|
* to avoid page allocator overhead. This slab needs
|
|
* to come after the other slabs with objects in
|
|
* order to fill them up. That way the size of the
|
|
* partial list stays small. kmem_cache_shrink can
|
|
* reclaim empty slabs from the partial list.
|
|
*/
|
|
add_partial_tail(n, page);
|
|
slab_unlock(page);
|
|
} else {
|
|
slab_unlock(page);
|
|
discard_slab(s, page);
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Remove the cpu slab
|
|
*/
|
|
static void deactivate_slab(struct kmem_cache *s, struct page *page, int cpu)
|
|
{
|
|
/*
|
|
* Merge cpu freelist into freelist. Typically we get here
|
|
* because both freelists are empty. So this is unlikely
|
|
* to occur.
|
|
*/
|
|
while (unlikely(page->lockless_freelist)) {
|
|
void **object;
|
|
|
|
/* Retrieve object from cpu_freelist */
|
|
object = page->lockless_freelist;
|
|
page->lockless_freelist = page->lockless_freelist[page->offset];
|
|
|
|
/* And put onto the regular freelist */
|
|
object[page->offset] = page->freelist;
|
|
page->freelist = object;
|
|
page->inuse--;
|
|
}
|
|
s->cpu_slab[cpu] = NULL;
|
|
unfreeze_slab(s, page);
|
|
}
|
|
|
|
static inline void flush_slab(struct kmem_cache *s, struct page *page, int cpu)
|
|
{
|
|
slab_lock(page);
|
|
deactivate_slab(s, page, cpu);
|
|
}
|
|
|
|
/*
|
|
* Flush cpu slab.
|
|
* Called from IPI handler with interrupts disabled.
|
|
*/
|
|
static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu)
|
|
{
|
|
struct page *page = s->cpu_slab[cpu];
|
|
|
|
if (likely(page))
|
|
flush_slab(s, page, cpu);
|
|
}
|
|
|
|
static void flush_cpu_slab(void *d)
|
|
{
|
|
struct kmem_cache *s = d;
|
|
int cpu = smp_processor_id();
|
|
|
|
__flush_cpu_slab(s, cpu);
|
|
}
|
|
|
|
static void flush_all(struct kmem_cache *s)
|
|
{
|
|
#ifdef CONFIG_SMP
|
|
on_each_cpu(flush_cpu_slab, s, 1, 1);
|
|
#else
|
|
unsigned long flags;
|
|
|
|
local_irq_save(flags);
|
|
flush_cpu_slab(s);
|
|
local_irq_restore(flags);
|
|
#endif
|
|
}
|
|
|
|
/*
|
|
* Slow path. The lockless freelist is empty or we need to perform
|
|
* debugging duties.
|
|
*
|
|
* Interrupts are disabled.
|
|
*
|
|
* 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 slowest path since we may sleep.
|
|
*/
|
|
static void *__slab_alloc(struct kmem_cache *s,
|
|
gfp_t gfpflags, int node, void *addr, struct page *page)
|
|
{
|
|
void **object;
|
|
int cpu = smp_processor_id();
|
|
|
|
if (!page)
|
|
goto new_slab;
|
|
|
|
slab_lock(page);
|
|
if (unlikely(node != -1 && page_to_nid(page) != node))
|
|
goto another_slab;
|
|
load_freelist:
|
|
object = page->freelist;
|
|
if (unlikely(!object))
|
|
goto another_slab;
|
|
if (unlikely(SlabDebug(page)))
|
|
goto debug;
|
|
|
|
object = page->freelist;
|
|
page->lockless_freelist = object[page->offset];
|
|
page->inuse = s->objects;
|
|
page->freelist = NULL;
|
|
slab_unlock(page);
|
|
return object;
|
|
|
|
another_slab:
|
|
deactivate_slab(s, page, cpu);
|
|
|
|
new_slab:
|
|
page = get_partial(s, gfpflags, node);
|
|
if (page) {
|
|
s->cpu_slab[cpu] = page;
|
|
goto load_freelist;
|
|
}
|
|
|
|
page = new_slab(s, gfpflags, node);
|
|
if (page) {
|
|
cpu = smp_processor_id();
|
|
if (s->cpu_slab[cpu]) {
|
|
/*
|
|
* Someone else populated the cpu_slab while we
|
|
* enabled interrupts, or we have gotten scheduled
|
|
* on another cpu. The page may not be on the
|
|
* requested node even if __GFP_THISNODE was
|
|
* specified. So we need to recheck.
|
|
*/
|
|
if (node == -1 ||
|
|
page_to_nid(s->cpu_slab[cpu]) == node) {
|
|
/*
|
|
* Current cpuslab is acceptable and we
|
|
* want the current one since its cache hot
|
|
*/
|
|
discard_slab(s, page);
|
|
page = s->cpu_slab[cpu];
|
|
slab_lock(page);
|
|
goto load_freelist;
|
|
}
|
|
/* New slab does not fit our expectations */
|
|
flush_slab(s, s->cpu_slab[cpu], cpu);
|
|
}
|
|
slab_lock(page);
|
|
SetSlabFrozen(page);
|
|
s->cpu_slab[cpu] = page;
|
|
goto load_freelist;
|
|
}
|
|
return NULL;
|
|
debug:
|
|
object = page->freelist;
|
|
if (!alloc_debug_processing(s, page, object, addr))
|
|
goto another_slab;
|
|
|
|
page->inuse++;
|
|
page->freelist = object[page->offset];
|
|
slab_unlock(page);
|
|
return object;
|
|
}
|
|
|
|
/*
|
|
* 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 void __always_inline *slab_alloc(struct kmem_cache *s,
|
|
gfp_t gfpflags, int node, void *addr)
|
|
{
|
|
struct page *page;
|
|
void **object;
|
|
unsigned long flags;
|
|
|
|
local_irq_save(flags);
|
|
page = s->cpu_slab[smp_processor_id()];
|
|
if (unlikely(!page || !page->lockless_freelist ||
|
|
(node != -1 && page_to_nid(page) != node)))
|
|
|
|
object = __slab_alloc(s, gfpflags, node, addr, page);
|
|
|
|
else {
|
|
object = page->lockless_freelist;
|
|
page->lockless_freelist = object[page->offset];
|
|
}
|
|
local_irq_restore(flags);
|
|
|
|
if (unlikely((gfpflags & __GFP_ZERO) && object))
|
|
memset(object, 0, s->objsize);
|
|
|
|
return object;
|
|
}
|
|
|
|
void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags)
|
|
{
|
|
return slab_alloc(s, gfpflags, -1, __builtin_return_address(0));
|
|
}
|
|
EXPORT_SYMBOL(kmem_cache_alloc);
|
|
|
|
#ifdef CONFIG_NUMA
|
|
void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node)
|
|
{
|
|
return slab_alloc(s, gfpflags, node, __builtin_return_address(0));
|
|
}
|
|
EXPORT_SYMBOL(kmem_cache_alloc_node);
|
|
#endif
|
|
|
|
/*
|
|
* Slow patch 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, void *addr)
|
|
{
|
|
void *prior;
|
|
void **object = (void *)x;
|
|
|
|
slab_lock(page);
|
|
|
|
if (unlikely(SlabDebug(page)))
|
|
goto debug;
|
|
checks_ok:
|
|
prior = object[page->offset] = page->freelist;
|
|
page->freelist = object;
|
|
page->inuse--;
|
|
|
|
if (unlikely(SlabFrozen(page)))
|
|
goto out_unlock;
|
|
|
|
if (unlikely(!page->inuse))
|
|
goto slab_empty;
|
|
|
|
/*
|
|
* Objects left in the slab. If it
|
|
* was not on the partial list before
|
|
* then add it.
|
|
*/
|
|
if (unlikely(!prior))
|
|
add_partial(get_node(s, page_to_nid(page)), page);
|
|
|
|
out_unlock:
|
|
slab_unlock(page);
|
|
return;
|
|
|
|
slab_empty:
|
|
if (prior)
|
|
/*
|
|
* Slab still on the partial list.
|
|
*/
|
|
remove_partial(s, page);
|
|
|
|
slab_unlock(page);
|
|
discard_slab(s, page);
|
|
return;
|
|
|
|
debug:
|
|
if (!free_debug_processing(s, page, x, addr))
|
|
goto out_unlock;
|
|
goto checks_ok;
|
|
}
|
|
|
|
/*
|
|
* 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 void __always_inline slab_free(struct kmem_cache *s,
|
|
struct page *page, void *x, void *addr)
|
|
{
|
|
void **object = (void *)x;
|
|
unsigned long flags;
|
|
|
|
local_irq_save(flags);
|
|
if (likely(page == s->cpu_slab[smp_processor_id()] &&
|
|
!SlabDebug(page))) {
|
|
object[page->offset] = page->lockless_freelist;
|
|
page->lockless_freelist = object;
|
|
} else
|
|
__slab_free(s, page, x, addr);
|
|
|
|
local_irq_restore(flags);
|
|
}
|
|
|
|
void kmem_cache_free(struct kmem_cache *s, void *x)
|
|
{
|
|
struct page *page;
|
|
|
|
page = virt_to_head_page(x);
|
|
|
|
slab_free(s, page, x, __builtin_return_address(0));
|
|
}
|
|
EXPORT_SYMBOL(kmem_cache_free);
|
|
|
|
/* Figure out on which slab object the object resides */
|
|
static struct page *get_object_page(const void *x)
|
|
{
|
|
struct page *page = virt_to_head_page(x);
|
|
|
|
if (!PageSlab(page))
|
|
return NULL;
|
|
|
|
return page;
|
|
}
|
|
|
|
/*
|
|
* 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 = DEFAULT_MAX_ORDER;
|
|
static int slub_min_objects = DEFAULT_MIN_OBJECTS;
|
|
|
|
/*
|
|
* Merge control. If this is set then no merging of slab caches will occur.
|
|
* (Could be removed. This was introduced to pacify the merge skeptics.)
|
|
*/
|
|
static int slub_nomerge;
|
|
|
|
/*
|
|
* 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 1/8th of the slab
|
|
* would be wasted.
|
|
*
|
|
* In order to reach satisfactory performance we must ensure that a minimum
|
|
* number of objects is in one slab. Otherwise we may generate too much
|
|
* activity on the partial lists 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 order;
|
|
int rem;
|
|
int min_order = slub_min_order;
|
|
|
|
/*
|
|
* If we would create too many object per slab then reduce
|
|
* the slab order even if it goes below slub_min_order.
|
|
*/
|
|
while (min_order > 0 &&
|
|
(PAGE_SIZE << min_order) >= MAX_OBJECTS_PER_SLAB * size)
|
|
min_order--;
|
|
|
|
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)
|
|
continue;
|
|
|
|
rem = slab_size % size;
|
|
|
|
if (rem <= slab_size / fract_leftover)
|
|
break;
|
|
|
|
/* If the next size is too high then exit now */
|
|
if (slab_size * 2 >= MAX_OBJECTS_PER_SLAB * size)
|
|
break;
|
|
}
|
|
|
|
return order;
|
|
}
|
|
|
|
static inline int calculate_order(int size)
|
|
{
|
|
int order;
|
|
int min_objects;
|
|
int fraction;
|
|
|
|
/*
|
|
* 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;
|
|
while (min_objects > 1) {
|
|
fraction = 8;
|
|
while (fraction >= 4) {
|
|
order = slab_order(size, min_objects,
|
|
slub_max_order, fraction);
|
|
if (order <= slub_max_order)
|
|
return order;
|
|
fraction /= 2;
|
|
}
|
|
min_objects /= 2;
|
|
}
|
|
|
|
/*
|
|
* 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);
|
|
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);
|
|
if (order <= MAX_ORDER)
|
|
return order;
|
|
return -ENOSYS;
|
|
}
|
|
|
|
/*
|
|
* Figure out what the alignment of the objects will be.
|
|
*/
|
|
static unsigned long calculate_alignment(unsigned long flags,
|
|
unsigned long align, unsigned long size)
|
|
{
|
|
/*
|
|
* If the user wants hardware cache aligned objects then
|
|
* follow that suggestion if the object is sufficiently
|
|
* large.
|
|
*
|
|
* The hardware cache alignment cannot override the
|
|
* specified alignment though. If that is greater
|
|
* then use it.
|
|
*/
|
|
if ((flags & SLAB_HWCACHE_ALIGN) &&
|
|
size > cache_line_size() / 2)
|
|
return max_t(unsigned long, align, cache_line_size());
|
|
|
|
if (align < ARCH_SLAB_MINALIGN)
|
|
return ARCH_SLAB_MINALIGN;
|
|
|
|
return ALIGN(align, sizeof(void *));
|
|
}
|
|
|
|
static void init_kmem_cache_node(struct kmem_cache_node *n)
|
|
{
|
|
n->nr_partial = 0;
|
|
atomic_long_set(&n->nr_slabs, 0);
|
|
spin_lock_init(&n->list_lock);
|
|
INIT_LIST_HEAD(&n->partial);
|
|
#ifdef CONFIG_SLUB_DEBUG
|
|
INIT_LIST_HEAD(&n->full);
|
|
#endif
|
|
}
|
|
|
|
#ifdef CONFIG_NUMA
|
|
/*
|
|
* No kmalloc_node yet so do it by hand. We know that this is the first
|
|
* slab on the node for this slabcache. There are no concurrent accesses
|
|
* possible.
|
|
*
|
|
* Note that this function only works on the kmalloc_node_cache
|
|
* when allocating for the kmalloc_node_cache.
|
|
*/
|
|
static struct kmem_cache_node * __init early_kmem_cache_node_alloc(gfp_t gfpflags,
|
|
int node)
|
|
{
|
|
struct page *page;
|
|
struct kmem_cache_node *n;
|
|
|
|
BUG_ON(kmalloc_caches->size < sizeof(struct kmem_cache_node));
|
|
|
|
page = new_slab(kmalloc_caches, gfpflags | GFP_THISNODE, node);
|
|
|
|
BUG_ON(!page);
|
|
n = page->freelist;
|
|
BUG_ON(!n);
|
|
page->freelist = get_freepointer(kmalloc_caches, n);
|
|
page->inuse++;
|
|
kmalloc_caches->node[node] = n;
|
|
#ifdef CONFIG_SLUB_DEBUG
|
|
init_object(kmalloc_caches, n, 1);
|
|
init_tracking(kmalloc_caches, n);
|
|
#endif
|
|
init_kmem_cache_node(n);
|
|
atomic_long_inc(&n->nr_slabs);
|
|
add_partial(n, page);
|
|
|
|
/*
|
|
* new_slab() disables interupts. If we do not reenable interrupts here
|
|
* then bootup would continue with interrupts disabled.
|
|
*/
|
|
local_irq_enable();
|
|
return n;
|
|
}
|
|
|
|
static void free_kmem_cache_nodes(struct kmem_cache *s)
|
|
{
|
|
int node;
|
|
|
|
for_each_online_node(node) {
|
|
struct kmem_cache_node *n = s->node[node];
|
|
if (n && n != &s->local_node)
|
|
kmem_cache_free(kmalloc_caches, n);
|
|
s->node[node] = NULL;
|
|
}
|
|
}
|
|
|
|
static int init_kmem_cache_nodes(struct kmem_cache *s, gfp_t gfpflags)
|
|
{
|
|
int node;
|
|
int local_node;
|
|
|
|
if (slab_state >= UP)
|
|
local_node = page_to_nid(virt_to_page(s));
|
|
else
|
|
local_node = 0;
|
|
|
|
for_each_online_node(node) {
|
|
struct kmem_cache_node *n;
|
|
|
|
if (local_node == node)
|
|
n = &s->local_node;
|
|
else {
|
|
if (slab_state == DOWN) {
|
|
n = early_kmem_cache_node_alloc(gfpflags,
|
|
node);
|
|
continue;
|
|
}
|
|
n = kmem_cache_alloc_node(kmalloc_caches,
|
|
gfpflags, node);
|
|
|
|
if (!n) {
|
|
free_kmem_cache_nodes(s);
|
|
return 0;
|
|
}
|
|
|
|
}
|
|
s->node[node] = n;
|
|
init_kmem_cache_node(n);
|
|
}
|
|
return 1;
|
|
}
|
|
#else
|
|
static void free_kmem_cache_nodes(struct kmem_cache *s)
|
|
{
|
|
}
|
|
|
|
static int init_kmem_cache_nodes(struct kmem_cache *s, gfp_t gfpflags)
|
|
{
|
|
init_kmem_cache_node(&s->local_node);
|
|
return 1;
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* calculate_sizes() determines the order and the distribution of data within
|
|
* a slab object.
|
|
*/
|
|
static int calculate_sizes(struct kmem_cache *s)
|
|
{
|
|
unsigned long flags = s->flags;
|
|
unsigned long size = s->objsize;
|
|
unsigned long align = s->align;
|
|
|
|
/*
|
|
* Determine if we can poison the object itself. If the user of
|
|
* the slab may touch the object after free or before allocation
|
|
* then we should never poison the object itself.
|
|
*/
|
|
if ((flags & SLAB_POISON) && !(flags & SLAB_DESTROY_BY_RCU) &&
|
|
!s->ctor)
|
|
s->flags |= __OBJECT_POISON;
|
|
else
|
|
s->flags &= ~__OBJECT_POISON;
|
|
|
|
/*
|
|
* Round up object size to the next word boundary. We can only
|
|
* place the free pointer at word boundaries and this determines
|
|
* the possible location of the free pointer.
|
|
*/
|
|
size = ALIGN(size, sizeof(void *));
|
|
|
|
#ifdef CONFIG_SLUB_DEBUG
|
|
/*
|
|
* 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->objsize)
|
|
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 an user writes before the start
|
|
* of the object.
|
|
*/
|
|
size += sizeof(void *);
|
|
#endif
|
|
|
|
/*
|
|
* Determine the alignment based on various parameters that the
|
|
* user specified and the dynamic determination of cache line size
|
|
* on bootup.
|
|
*/
|
|
align = calculate_alignment(flags, align, s->objsize);
|
|
|
|
/*
|
|
* SLUB stores one object immediately after another beginning from
|
|
* offset 0. In order to align the objects we have to simply size
|
|
* each object to conform to the alignment.
|
|
*/
|
|
size = ALIGN(size, align);
|
|
s->size = size;
|
|
|
|
s->order = calculate_order(size);
|
|
if (s->order < 0)
|
|
return 0;
|
|
|
|
/*
|
|
* Determine the number of objects per slab
|
|
*/
|
|
s->objects = (PAGE_SIZE << s->order) / size;
|
|
|
|
/*
|
|
* Verify that the number of objects is within permitted limits.
|
|
* The page->inuse field is only 16 bit wide! So we cannot have
|
|
* more than 64k objects per slab.
|
|
*/
|
|
if (!s->objects || s->objects > MAX_OBJECTS_PER_SLAB)
|
|
return 0;
|
|
return 1;
|
|
|
|
}
|
|
|
|
static int kmem_cache_open(struct kmem_cache *s, gfp_t gfpflags,
|
|
const char *name, size_t size,
|
|
size_t align, unsigned long flags,
|
|
void (*ctor)(void *, struct kmem_cache *, unsigned long))
|
|
{
|
|
memset(s, 0, kmem_size);
|
|
s->name = name;
|
|
s->ctor = ctor;
|
|
s->objsize = size;
|
|
s->flags = flags;
|
|
s->align = align;
|
|
kmem_cache_open_debug_check(s);
|
|
|
|
if (!calculate_sizes(s))
|
|
goto error;
|
|
|
|
s->refcount = 1;
|
|
#ifdef CONFIG_NUMA
|
|
s->defrag_ratio = 100;
|
|
#endif
|
|
|
|
if (init_kmem_cache_nodes(s, gfpflags & ~SLUB_DMA))
|
|
return 1;
|
|
error:
|
|
if (flags & SLAB_PANIC)
|
|
panic("Cannot create slab %s size=%lu realsize=%u "
|
|
"order=%u offset=%u flags=%lx\n",
|
|
s->name, (unsigned long)size, s->size, s->order,
|
|
s->offset, flags);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Check if a given pointer is valid
|
|
*/
|
|
int kmem_ptr_validate(struct kmem_cache *s, const void *object)
|
|
{
|
|
struct page * page;
|
|
|
|
page = get_object_page(object);
|
|
|
|
if (!page || s != page->slab)
|
|
/* No slab or wrong slab */
|
|
return 0;
|
|
|
|
if (!check_valid_pointer(s, page, object))
|
|
return 0;
|
|
|
|
/*
|
|
* We could also check if the object is on the slabs freelist.
|
|
* But this would be too expensive and it seems that the main
|
|
* purpose of kmem_ptr_valid is to check if the object belongs
|
|
* to a certain slab.
|
|
*/
|
|
return 1;
|
|
}
|
|
EXPORT_SYMBOL(kmem_ptr_validate);
|
|
|
|
/*
|
|
* Determine the size of a slab object
|
|
*/
|
|
unsigned int kmem_cache_size(struct kmem_cache *s)
|
|
{
|
|
return s->objsize;
|
|
}
|
|
EXPORT_SYMBOL(kmem_cache_size);
|
|
|
|
const char *kmem_cache_name(struct kmem_cache *s)
|
|
{
|
|
return s->name;
|
|
}
|
|
EXPORT_SYMBOL(kmem_cache_name);
|
|
|
|
/*
|
|
* Attempt to free all slabs on a node. Return the number of slabs we
|
|
* were unable to free.
|
|
*/
|
|
static int free_list(struct kmem_cache *s, struct kmem_cache_node *n,
|
|
struct list_head *list)
|
|
{
|
|
int slabs_inuse = 0;
|
|
unsigned long flags;
|
|
struct page *page, *h;
|
|
|
|
spin_lock_irqsave(&n->list_lock, flags);
|
|
list_for_each_entry_safe(page, h, list, lru)
|
|
if (!page->inuse) {
|
|
list_del(&page->lru);
|
|
discard_slab(s, page);
|
|
} else
|
|
slabs_inuse++;
|
|
spin_unlock_irqrestore(&n->list_lock, flags);
|
|
return slabs_inuse;
|
|
}
|
|
|
|
/*
|
|
* Release all resources used by a slab cache.
|
|
*/
|
|
static inline int kmem_cache_close(struct kmem_cache *s)
|
|
{
|
|
int node;
|
|
|
|
flush_all(s);
|
|
|
|
/* Attempt to free all objects */
|
|
for_each_online_node(node) {
|
|
struct kmem_cache_node *n = get_node(s, node);
|
|
|
|
n->nr_partial -= free_list(s, n, &n->partial);
|
|
if (atomic_long_read(&n->nr_slabs))
|
|
return 1;
|
|
}
|
|
free_kmem_cache_nodes(s);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Close a cache and release the kmem_cache structure
|
|
* (must be used for caches created using kmem_cache_create)
|
|
*/
|
|
void kmem_cache_destroy(struct kmem_cache *s)
|
|
{
|
|
down_write(&slub_lock);
|
|
s->refcount--;
|
|
if (!s->refcount) {
|
|
list_del(&s->list);
|
|
up_write(&slub_lock);
|
|
if (kmem_cache_close(s))
|
|
WARN_ON(1);
|
|
sysfs_slab_remove(s);
|
|
kfree(s);
|
|
} else
|
|
up_write(&slub_lock);
|
|
}
|
|
EXPORT_SYMBOL(kmem_cache_destroy);
|
|
|
|
/********************************************************************
|
|
* Kmalloc subsystem
|
|
*******************************************************************/
|
|
|
|
struct kmem_cache kmalloc_caches[KMALLOC_SHIFT_HIGH + 1] __cacheline_aligned;
|
|
EXPORT_SYMBOL(kmalloc_caches);
|
|
|
|
#ifdef CONFIG_ZONE_DMA
|
|
static struct kmem_cache *kmalloc_caches_dma[KMALLOC_SHIFT_HIGH + 1];
|
|
#endif
|
|
|
|
static int __init setup_slub_min_order(char *str)
|
|
{
|
|
get_option (&str, &slub_min_order);
|
|
|
|
return 1;
|
|
}
|
|
|
|
__setup("slub_min_order=", setup_slub_min_order);
|
|
|
|
static int __init setup_slub_max_order(char *str)
|
|
{
|
|
get_option (&str, &slub_max_order);
|
|
|
|
return 1;
|
|
}
|
|
|
|
__setup("slub_max_order=", setup_slub_max_order);
|
|
|
|
static int __init setup_slub_min_objects(char *str)
|
|
{
|
|
get_option (&str, &slub_min_objects);
|
|
|
|
return 1;
|
|
}
|
|
|
|
__setup("slub_min_objects=", setup_slub_min_objects);
|
|
|
|
static int __init setup_slub_nomerge(char *str)
|
|
{
|
|
slub_nomerge = 1;
|
|
return 1;
|
|
}
|
|
|
|
__setup("slub_nomerge", setup_slub_nomerge);
|
|
|
|
static struct kmem_cache *create_kmalloc_cache(struct kmem_cache *s,
|
|
const char *name, int size, gfp_t gfp_flags)
|
|
{
|
|
unsigned int flags = 0;
|
|
|
|
if (gfp_flags & SLUB_DMA)
|
|
flags = SLAB_CACHE_DMA;
|
|
|
|
down_write(&slub_lock);
|
|
if (!kmem_cache_open(s, gfp_flags, name, size, ARCH_KMALLOC_MINALIGN,
|
|
flags, NULL))
|
|
goto panic;
|
|
|
|
list_add(&s->list, &slab_caches);
|
|
up_write(&slub_lock);
|
|
if (sysfs_slab_add(s))
|
|
goto panic;
|
|
return s;
|
|
|
|
panic:
|
|
panic("Creation of kmalloc slab %s size=%d failed.\n", name, size);
|
|
}
|
|
|
|
#ifdef CONFIG_ZONE_DMA
|
|
static noinline struct kmem_cache *dma_kmalloc_cache(int index, gfp_t flags)
|
|
{
|
|
struct kmem_cache *s;
|
|
struct kmem_cache *x;
|
|
char *text;
|
|
size_t realsize;
|
|
|
|
s = kmalloc_caches_dma[index];
|
|
if (s)
|
|
return s;
|
|
|
|
/* Dynamically create dma cache */
|
|
x = kmalloc(kmem_size, flags & ~SLUB_DMA);
|
|
if (!x)
|
|
panic("Unable to allocate memory for dma cache\n");
|
|
|
|
realsize = kmalloc_caches[index].objsize;
|
|
text = kasprintf(flags & ~SLUB_DMA, "kmalloc_dma-%d",
|
|
(unsigned int)realsize);
|
|
s = create_kmalloc_cache(x, text, realsize, flags);
|
|
down_write(&slub_lock);
|
|
if (!kmalloc_caches_dma[index]) {
|
|
kmalloc_caches_dma[index] = s;
|
|
up_write(&slub_lock);
|
|
return s;
|
|
}
|
|
up_write(&slub_lock);
|
|
kmem_cache_destroy(s);
|
|
return kmalloc_caches_dma[index];
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* Conversion table for small slabs sizes / 8 to the index in the
|
|
* kmalloc array. This is necessary for slabs < 192 since we have non power
|
|
* of two cache sizes there. The size of larger slabs can be determined using
|
|
* fls.
|
|
*/
|
|
static s8 size_index[24] = {
|
|
3, /* 8 */
|
|
4, /* 16 */
|
|
5, /* 24 */
|
|
5, /* 32 */
|
|
6, /* 40 */
|
|
6, /* 48 */
|
|
6, /* 56 */
|
|
6, /* 64 */
|
|
1, /* 72 */
|
|
1, /* 80 */
|
|
1, /* 88 */
|
|
1, /* 96 */
|
|
7, /* 104 */
|
|
7, /* 112 */
|
|
7, /* 120 */
|
|
7, /* 128 */
|
|
2, /* 136 */
|
|
2, /* 144 */
|
|
2, /* 152 */
|
|
2, /* 160 */
|
|
2, /* 168 */
|
|
2, /* 176 */
|
|
2, /* 184 */
|
|
2 /* 192 */
|
|
};
|
|
|
|
static struct kmem_cache *get_slab(size_t size, gfp_t flags)
|
|
{
|
|
int index;
|
|
|
|
if (size <= 192) {
|
|
if (!size)
|
|
return ZERO_SIZE_PTR;
|
|
|
|
index = size_index[(size - 1) / 8];
|
|
} else {
|
|
if (size > KMALLOC_MAX_SIZE)
|
|
return NULL;
|
|
|
|
index = fls(size - 1);
|
|
}
|
|
|
|
#ifdef CONFIG_ZONE_DMA
|
|
if (unlikely((flags & SLUB_DMA)))
|
|
return dma_kmalloc_cache(index, flags);
|
|
|
|
#endif
|
|
return &kmalloc_caches[index];
|
|
}
|
|
|
|
void *__kmalloc(size_t size, gfp_t flags)
|
|
{
|
|
struct kmem_cache *s = get_slab(size, flags);
|
|
|
|
if (ZERO_OR_NULL_PTR(s))
|
|
return s;
|
|
|
|
return slab_alloc(s, flags, -1, __builtin_return_address(0));
|
|
}
|
|
EXPORT_SYMBOL(__kmalloc);
|
|
|
|
#ifdef CONFIG_NUMA
|
|
void *__kmalloc_node(size_t size, gfp_t flags, int node)
|
|
{
|
|
struct kmem_cache *s = get_slab(size, flags);
|
|
|
|
if (ZERO_OR_NULL_PTR(s))
|
|
return s;
|
|
|
|
return slab_alloc(s, flags, node, __builtin_return_address(0));
|
|
}
|
|
EXPORT_SYMBOL(__kmalloc_node);
|
|
#endif
|
|
|
|
size_t ksize(const void *object)
|
|
{
|
|
struct page *page;
|
|
struct kmem_cache *s;
|
|
|
|
if (ZERO_OR_NULL_PTR(object))
|
|
return 0;
|
|
|
|
page = get_object_page(object);
|
|
BUG_ON(!page);
|
|
s = page->slab;
|
|
BUG_ON(!s);
|
|
|
|
/*
|
|
* Debugging requires use of the padding between object
|
|
* and whatever may come after it.
|
|
*/
|
|
if (s->flags & (SLAB_RED_ZONE | SLAB_POISON))
|
|
return s->objsize;
|
|
|
|
/*
|
|
* If we have the need to store the freelist pointer
|
|
* back there or track user information then we can
|
|
* only use the space before that information.
|
|
*/
|
|
if (s->flags & (SLAB_DESTROY_BY_RCU | SLAB_STORE_USER))
|
|
return s->inuse;
|
|
|
|
/*
|
|
* Else we can use all the padding etc for the allocation
|
|
*/
|
|
return s->size;
|
|
}
|
|
EXPORT_SYMBOL(ksize);
|
|
|
|
void kfree(const void *x)
|
|
{
|
|
struct kmem_cache *s;
|
|
struct page *page;
|
|
|
|
/*
|
|
* This has to be an unsigned comparison. According to Linus
|
|
* some gcc version treat a pointer as a signed entity. Then
|
|
* this comparison would be true for all "negative" pointers
|
|
* (which would cover the whole upper half of the address space).
|
|
*/
|
|
if (ZERO_OR_NULL_PTR(x))
|
|
return;
|
|
|
|
page = virt_to_head_page(x);
|
|
s = page->slab;
|
|
|
|
slab_free(s, page, (void *)x, __builtin_return_address(0));
|
|
}
|
|
EXPORT_SYMBOL(kfree);
|
|
|
|
/*
|
|
* kmem_cache_shrink removes empty slabs from the partial lists and sorts
|
|
* the remaining slabs by the number of items in use. The slabs with the
|
|
* most items in use come first. 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)
|
|
{
|
|
int node;
|
|
int i;
|
|
struct kmem_cache_node *n;
|
|
struct page *page;
|
|
struct page *t;
|
|
struct list_head *slabs_by_inuse =
|
|
kmalloc(sizeof(struct list_head) * s->objects, GFP_KERNEL);
|
|
unsigned long flags;
|
|
|
|
if (!slabs_by_inuse)
|
|
return -ENOMEM;
|
|
|
|
flush_all(s);
|
|
for_each_online_node(node) {
|
|
n = get_node(s, node);
|
|
|
|
if (!n->nr_partial)
|
|
continue;
|
|
|
|
for (i = 0; i < s->objects; i++)
|
|
INIT_LIST_HEAD(slabs_by_inuse + i);
|
|
|
|
spin_lock_irqsave(&n->list_lock, flags);
|
|
|
|
/*
|
|
* Build lists indexed by the items in use in each slab.
|
|
*
|
|
* 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) {
|
|
if (!page->inuse && slab_trylock(page)) {
|
|
/*
|
|
* Must hold slab lock here because slab_free
|
|
* may have freed the last object and be
|
|
* waiting to release the slab.
|
|
*/
|
|
list_del(&page->lru);
|
|
n->nr_partial--;
|
|
slab_unlock(page);
|
|
discard_slab(s, page);
|
|
} else {
|
|
if (n->nr_partial > MAX_PARTIAL)
|
|
list_move(&page->lru,
|
|
slabs_by_inuse + page->inuse);
|
|
}
|
|
}
|
|
|
|
if (n->nr_partial <= MAX_PARTIAL)
|
|
goto out;
|
|
|
|
/*
|
|
* Rebuild the partial list with the slabs filled up most
|
|
* first and the least used slabs at the end.
|
|
*/
|
|
for (i = s->objects - 1; i >= 0; i--)
|
|
list_splice(slabs_by_inuse + i, n->partial.prev);
|
|
|
|
out:
|
|
spin_unlock_irqrestore(&n->list_lock, flags);
|
|
}
|
|
|
|
kfree(slabs_by_inuse);
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(kmem_cache_shrink);
|
|
|
|
/********************************************************************
|
|
* Basic setup of slabs
|
|
*******************************************************************/
|
|
|
|
void __init kmem_cache_init(void)
|
|
{
|
|
int i;
|
|
int caches = 0;
|
|
|
|
#ifdef CONFIG_NUMA
|
|
/*
|
|
* Must first have the slab cache available for the allocations of the
|
|
* struct kmem_cache_node's. There is special bootstrap code in
|
|
* kmem_cache_open for slab_state == DOWN.
|
|
*/
|
|
create_kmalloc_cache(&kmalloc_caches[0], "kmem_cache_node",
|
|
sizeof(struct kmem_cache_node), GFP_KERNEL);
|
|
kmalloc_caches[0].refcount = -1;
|
|
caches++;
|
|
#endif
|
|
|
|
/* Able to allocate the per node structures */
|
|
slab_state = PARTIAL;
|
|
|
|
/* Caches that are not of the two-to-the-power-of size */
|
|
if (KMALLOC_MIN_SIZE <= 64) {
|
|
create_kmalloc_cache(&kmalloc_caches[1],
|
|
"kmalloc-96", 96, GFP_KERNEL);
|
|
caches++;
|
|
}
|
|
if (KMALLOC_MIN_SIZE <= 128) {
|
|
create_kmalloc_cache(&kmalloc_caches[2],
|
|
"kmalloc-192", 192, GFP_KERNEL);
|
|
caches++;
|
|
}
|
|
|
|
for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++) {
|
|
create_kmalloc_cache(&kmalloc_caches[i],
|
|
"kmalloc", 1 << i, GFP_KERNEL);
|
|
caches++;
|
|
}
|
|
|
|
|
|
/*
|
|
* Patch up the size_index table if we have strange large alignment
|
|
* requirements for the kmalloc array. This is only the case for
|
|
* mips it seems. The standard arches will not generate any code here.
|
|
*
|
|
* Largest permitted alignment is 256 bytes due to the way we
|
|
* handle the index determination for the smaller caches.
|
|
*
|
|
* Make sure that nothing crazy happens if someone starts tinkering
|
|
* around with ARCH_KMALLOC_MINALIGN
|
|
*/
|
|
BUILD_BUG_ON(KMALLOC_MIN_SIZE > 256 ||
|
|
(KMALLOC_MIN_SIZE & (KMALLOC_MIN_SIZE - 1)));
|
|
|
|
for (i = 8; i < KMALLOC_MIN_SIZE; i += 8)
|
|
size_index[(i - 1) / 8] = KMALLOC_SHIFT_LOW;
|
|
|
|
slab_state = UP;
|
|
|
|
/* Provide the correct kmalloc names now that the caches are up */
|
|
for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++)
|
|
kmalloc_caches[i]. name =
|
|
kasprintf(GFP_KERNEL, "kmalloc-%d", 1 << i);
|
|
|
|
#ifdef CONFIG_SMP
|
|
register_cpu_notifier(&slab_notifier);
|
|
#endif
|
|
|
|
kmem_size = offsetof(struct kmem_cache, cpu_slab) +
|
|
nr_cpu_ids * sizeof(struct page *);
|
|
|
|
printk(KERN_INFO "SLUB: Genslabs=%d, HWalign=%d, Order=%d-%d, MinObjects=%d,"
|
|
" CPUs=%d, Nodes=%d\n",
|
|
caches, cache_line_size(),
|
|
slub_min_order, slub_max_order, slub_min_objects,
|
|
nr_cpu_ids, nr_node_ids);
|
|
}
|
|
|
|
/*
|
|
* Find a mergeable slab cache
|
|
*/
|
|
static int slab_unmergeable(struct kmem_cache *s)
|
|
{
|
|
if (slub_nomerge || (s->flags & SLUB_NEVER_MERGE))
|
|
return 1;
|
|
|
|
if (s->ctor)
|
|
return 1;
|
|
|
|
/*
|
|
* We may have set a slab to be unmergeable during bootstrap.
|
|
*/
|
|
if (s->refcount < 0)
|
|
return 1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static struct kmem_cache *find_mergeable(size_t size,
|
|
size_t align, unsigned long flags,
|
|
void (*ctor)(void *, struct kmem_cache *, unsigned long))
|
|
{
|
|
struct kmem_cache *s;
|
|
|
|
if (slub_nomerge || (flags & SLUB_NEVER_MERGE))
|
|
return NULL;
|
|
|
|
if (ctor)
|
|
return NULL;
|
|
|
|
size = ALIGN(size, sizeof(void *));
|
|
align = calculate_alignment(flags, align, size);
|
|
size = ALIGN(size, align);
|
|
|
|
list_for_each_entry(s, &slab_caches, list) {
|
|
if (slab_unmergeable(s))
|
|
continue;
|
|
|
|
if (size > s->size)
|
|
continue;
|
|
|
|
if (((flags | slub_debug) & SLUB_MERGE_SAME) !=
|
|
(s->flags & SLUB_MERGE_SAME))
|
|
continue;
|
|
/*
|
|
* Check if alignment is compatible.
|
|
* Courtesy of Adrian Drzewiecki
|
|
*/
|
|
if ((s->size & ~(align -1)) != s->size)
|
|
continue;
|
|
|
|
if (s->size - size >= sizeof(void *))
|
|
continue;
|
|
|
|
return s;
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
struct kmem_cache *kmem_cache_create(const char *name, size_t size,
|
|
size_t align, unsigned long flags,
|
|
void (*ctor)(void *, struct kmem_cache *, unsigned long),
|
|
void (*dtor)(void *, struct kmem_cache *, unsigned long))
|
|
{
|
|
struct kmem_cache *s;
|
|
|
|
BUG_ON(dtor);
|
|
down_write(&slub_lock);
|
|
s = find_mergeable(size, align, flags, ctor);
|
|
if (s) {
|
|
s->refcount++;
|
|
/*
|
|
* Adjust the object sizes so that we clear
|
|
* the complete object on kzalloc.
|
|
*/
|
|
s->objsize = max(s->objsize, (int)size);
|
|
s->inuse = max_t(int, s->inuse, ALIGN(size, sizeof(void *)));
|
|
up_write(&slub_lock);
|
|
if (sysfs_slab_alias(s, name))
|
|
goto err;
|
|
return s;
|
|
}
|
|
s = kmalloc(kmem_size, GFP_KERNEL);
|
|
if (s) {
|
|
if (kmem_cache_open(s, GFP_KERNEL, name,
|
|
size, align, flags, ctor)) {
|
|
list_add(&s->list, &slab_caches);
|
|
up_write(&slub_lock);
|
|
if (sysfs_slab_add(s))
|
|
goto err;
|
|
return s;
|
|
}
|
|
kfree(s);
|
|
}
|
|
up_write(&slub_lock);
|
|
|
|
err:
|
|
if (flags & SLAB_PANIC)
|
|
panic("Cannot create slabcache %s\n", name);
|
|
else
|
|
s = NULL;
|
|
return s;
|
|
}
|
|
EXPORT_SYMBOL(kmem_cache_create);
|
|
|
|
#ifdef CONFIG_SMP
|
|
/*
|
|
* Use the cpu notifier to insure that the cpu slabs are flushed when
|
|
* necessary.
|
|
*/
|
|
static int __cpuinit 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:
|
|
down_read(&slub_lock);
|
|
list_for_each_entry(s, &slab_caches, list) {
|
|
local_irq_save(flags);
|
|
__flush_cpu_slab(s, cpu);
|
|
local_irq_restore(flags);
|
|
}
|
|
up_read(&slub_lock);
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
return NOTIFY_OK;
|
|
}
|
|
|
|
static struct notifier_block __cpuinitdata slab_notifier =
|
|
{ &slab_cpuup_callback, NULL, 0 };
|
|
|
|
#endif
|
|
|
|
void *__kmalloc_track_caller(size_t size, gfp_t gfpflags, void *caller)
|
|
{
|
|
struct kmem_cache *s = get_slab(size, gfpflags);
|
|
|
|
if (ZERO_OR_NULL_PTR(s))
|
|
return s;
|
|
|
|
return slab_alloc(s, gfpflags, -1, caller);
|
|
}
|
|
|
|
void *__kmalloc_node_track_caller(size_t size, gfp_t gfpflags,
|
|
int node, void *caller)
|
|
{
|
|
struct kmem_cache *s = get_slab(size, gfpflags);
|
|
|
|
if (ZERO_OR_NULL_PTR(s))
|
|
return s;
|
|
|
|
return slab_alloc(s, gfpflags, node, caller);
|
|
}
|
|
|
|
#if defined(CONFIG_SYSFS) && defined(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, s->objects);
|
|
|
|
for_each_free_object(p, s, page->freelist) {
|
|
set_bit(slab_index(p, s, addr), map);
|
|
if (!check_object(s, page, p, 0))
|
|
return 0;
|
|
}
|
|
|
|
for_each_object(p, s, addr)
|
|
if (!test_bit(slab_index(p, s, addr), map))
|
|
if (!check_object(s, page, p, 1))
|
|
return 0;
|
|
return 1;
|
|
}
|
|
|
|
static void validate_slab_slab(struct kmem_cache *s, struct page *page,
|
|
unsigned long *map)
|
|
{
|
|
if (slab_trylock(page)) {
|
|
validate_slab(s, page, map);
|
|
slab_unlock(page);
|
|
} else
|
|
printk(KERN_INFO "SLUB %s: Skipped busy slab 0x%p\n",
|
|
s->name, page);
|
|
|
|
if (s->flags & DEBUG_DEFAULT_FLAGS) {
|
|
if (!SlabDebug(page))
|
|
printk(KERN_ERR "SLUB %s: SlabDebug not set "
|
|
"on slab 0x%p\n", s->name, page);
|
|
} else {
|
|
if (SlabDebug(page))
|
|
printk(KERN_ERR "SLUB %s: SlabDebug set on "
|
|
"slab 0x%p\n", s->name, 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;
|
|
|
|
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)
|
|
printk(KERN_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))
|
|
printk(KERN_ERR "SLUB: %s %ld slabs counted but "
|
|
"counter=%ld\n", s->name, count,
|
|
atomic_long_read(&n->nr_slabs));
|
|
|
|
out:
|
|
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(s->objects) *
|
|
sizeof(unsigned long), GFP_KERNEL);
|
|
|
|
if (!map)
|
|
return -ENOMEM;
|
|
|
|
flush_all(s);
|
|
for_each_online_node(node) {
|
|
struct kmem_cache_node *n = get_node(s, node);
|
|
|
|
count += validate_slab_node(s, n, map);
|
|
}
|
|
kfree(map);
|
|
return count;
|
|
}
|
|
|
|
#ifdef SLUB_RESILIENCY_TEST
|
|
static void resiliency_test(void)
|
|
{
|
|
u8 *p;
|
|
|
|
printk(KERN_ERR "SLUB resiliency testing\n");
|
|
printk(KERN_ERR "-----------------------\n");
|
|
printk(KERN_ERR "A. Corruption after allocation\n");
|
|
|
|
p = kzalloc(16, GFP_KERNEL);
|
|
p[16] = 0x12;
|
|
printk(KERN_ERR "\n1. kmalloc-16: Clobber Redzone/next pointer"
|
|
" 0x12->0x%p\n\n", p + 16);
|
|
|
|
validate_slab_cache(kmalloc_caches + 4);
|
|
|
|
/* Hmmm... The next two are dangerous */
|
|
p = kzalloc(32, GFP_KERNEL);
|
|
p[32 + sizeof(void *)] = 0x34;
|
|
printk(KERN_ERR "\n2. kmalloc-32: Clobber next pointer/next slab"
|
|
" 0x34 -> -0x%p\n", p);
|
|
printk(KERN_ERR "If allocated object is overwritten then not detectable\n\n");
|
|
|
|
validate_slab_cache(kmalloc_caches + 5);
|
|
p = kzalloc(64, GFP_KERNEL);
|
|
p += 64 + (get_cycles() & 0xff) * sizeof(void *);
|
|
*p = 0x56;
|
|
printk(KERN_ERR "\n3. kmalloc-64: corrupting random byte 0x56->0x%p\n",
|
|
p);
|
|
printk(KERN_ERR "If allocated object is overwritten then not detectable\n\n");
|
|
validate_slab_cache(kmalloc_caches + 6);
|
|
|
|
printk(KERN_ERR "\nB. Corruption after free\n");
|
|
p = kzalloc(128, GFP_KERNEL);
|
|
kfree(p);
|
|
*p = 0x78;
|
|
printk(KERN_ERR "1. kmalloc-128: Clobber first word 0x78->0x%p\n\n", p);
|
|
validate_slab_cache(kmalloc_caches + 7);
|
|
|
|
p = kzalloc(256, GFP_KERNEL);
|
|
kfree(p);
|
|
p[50] = 0x9a;
|
|
printk(KERN_ERR "\n2. kmalloc-256: Clobber 50th byte 0x9a->0x%p\n\n", p);
|
|
validate_slab_cache(kmalloc_caches + 8);
|
|
|
|
p = kzalloc(512, GFP_KERNEL);
|
|
kfree(p);
|
|
p[512] = 0xab;
|
|
printk(KERN_ERR "\n3. kmalloc-512: Clobber redzone 0xab->0x%p\n\n", p);
|
|
validate_slab_cache(kmalloc_caches + 9);
|
|
}
|
|
#else
|
|
static void resiliency_test(void) {};
|
|
#endif
|
|
|
|
/*
|
|
* Generate lists of code addresses where slabcache objects are allocated
|
|
* and freed.
|
|
*/
|
|
|
|
struct location {
|
|
unsigned long count;
|
|
void *addr;
|
|
long long sum_time;
|
|
long min_time;
|
|
long max_time;
|
|
long min_pid;
|
|
long max_pid;
|
|
cpumask_t 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;
|
|
void *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;
|
|
|
|
cpu_set(track->cpu, 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;
|
|
cpus_clear(l->cpus);
|
|
cpu_set(track->cpu, 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)
|
|
{
|
|
void *addr = page_address(page);
|
|
DECLARE_BITMAP(map, s->objects);
|
|
void *p;
|
|
|
|
bitmap_zero(map, s->objects);
|
|
for_each_free_object(p, s, page->freelist)
|
|
set_bit(slab_index(p, s, addr), map);
|
|
|
|
for_each_object(p, s, addr)
|
|
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 n = 0;
|
|
unsigned long i;
|
|
struct loc_track t = { 0, 0, NULL };
|
|
int node;
|
|
|
|
if (!alloc_loc_track(&t, PAGE_SIZE / sizeof(struct location),
|
|
GFP_KERNEL))
|
|
return sprintf(buf, "Out of memory\n");
|
|
|
|
/* Push back cpu slabs */
|
|
flush_all(s);
|
|
|
|
for_each_online_node(node) {
|
|
struct kmem_cache_node *n = get_node(s, node);
|
|
unsigned long flags;
|
|
struct page *page;
|
|
|
|
if (!atomic_read(&n->nr_slabs))
|
|
continue;
|
|
|
|
spin_lock_irqsave(&n->list_lock, flags);
|
|
list_for_each_entry(page, &n->partial, lru)
|
|
process_slab(&t, s, page, alloc);
|
|
list_for_each_entry(page, &n->full, lru)
|
|
process_slab(&t, s, page, alloc);
|
|
spin_unlock_irqrestore(&n->list_lock, flags);
|
|
}
|
|
|
|
for (i = 0; i < t.count; i++) {
|
|
struct location *l = &t.loc[i];
|
|
|
|
if (n > PAGE_SIZE - 100)
|
|
break;
|
|
n += sprintf(buf + n, "%7ld ", l->count);
|
|
|
|
if (l->addr)
|
|
n += sprint_symbol(buf + n, (unsigned long)l->addr);
|
|
else
|
|
n += sprintf(buf + n, "<not-available>");
|
|
|
|
if (l->sum_time != l->min_time) {
|
|
unsigned long remainder;
|
|
|
|
n += sprintf(buf + n, " age=%ld/%ld/%ld",
|
|
l->min_time,
|
|
div_long_long_rem(l->sum_time, l->count, &remainder),
|
|
l->max_time);
|
|
} else
|
|
n += sprintf(buf + n, " age=%ld",
|
|
l->min_time);
|
|
|
|
if (l->min_pid != l->max_pid)
|
|
n += sprintf(buf + n, " pid=%ld-%ld",
|
|
l->min_pid, l->max_pid);
|
|
else
|
|
n += sprintf(buf + n, " pid=%ld",
|
|
l->min_pid);
|
|
|
|
if (num_online_cpus() > 1 && !cpus_empty(l->cpus) &&
|
|
n < PAGE_SIZE - 60) {
|
|
n += sprintf(buf + n, " cpus=");
|
|
n += cpulist_scnprintf(buf + n, PAGE_SIZE - n - 50,
|
|
l->cpus);
|
|
}
|
|
|
|
if (num_online_nodes() > 1 && !nodes_empty(l->nodes) &&
|
|
n < PAGE_SIZE - 60) {
|
|
n += sprintf(buf + n, " nodes=");
|
|
n += nodelist_scnprintf(buf + n, PAGE_SIZE - n - 50,
|
|
l->nodes);
|
|
}
|
|
|
|
n += sprintf(buf + n, "\n");
|
|
}
|
|
|
|
free_loc_track(&t);
|
|
if (!t.count)
|
|
n += sprintf(buf, "No data\n");
|
|
return n;
|
|
}
|
|
|
|
static unsigned long count_partial(struct kmem_cache_node *n)
|
|
{
|
|
unsigned long flags;
|
|
unsigned long x = 0;
|
|
struct page *page;
|
|
|
|
spin_lock_irqsave(&n->list_lock, flags);
|
|
list_for_each_entry(page, &n->partial, lru)
|
|
x += page->inuse;
|
|
spin_unlock_irqrestore(&n->list_lock, flags);
|
|
return x;
|
|
}
|
|
|
|
enum slab_stat_type {
|
|
SL_FULL,
|
|
SL_PARTIAL,
|
|
SL_CPU,
|
|
SL_OBJECTS
|
|
};
|
|
|
|
#define SO_FULL (1 << SL_FULL)
|
|
#define SO_PARTIAL (1 << SL_PARTIAL)
|
|
#define SO_CPU (1 << SL_CPU)
|
|
#define SO_OBJECTS (1 << SL_OBJECTS)
|
|
|
|
static unsigned long slab_objects(struct kmem_cache *s,
|
|
char *buf, unsigned long flags)
|
|
{
|
|
unsigned long total = 0;
|
|
int cpu;
|
|
int node;
|
|
int x;
|
|
unsigned long *nodes;
|
|
unsigned long *per_cpu;
|
|
|
|
nodes = kzalloc(2 * sizeof(unsigned long) * nr_node_ids, GFP_KERNEL);
|
|
per_cpu = nodes + nr_node_ids;
|
|
|
|
for_each_possible_cpu(cpu) {
|
|
struct page *page = s->cpu_slab[cpu];
|
|
int node;
|
|
|
|
if (page) {
|
|
node = page_to_nid(page);
|
|
if (flags & SO_CPU) {
|
|
int x = 0;
|
|
|
|
if (flags & SO_OBJECTS)
|
|
x = page->inuse;
|
|
else
|
|
x = 1;
|
|
total += x;
|
|
nodes[node] += x;
|
|
}
|
|
per_cpu[node]++;
|
|
}
|
|
}
|
|
|
|
for_each_online_node(node) {
|
|
struct kmem_cache_node *n = get_node(s, node);
|
|
|
|
if (flags & SO_PARTIAL) {
|
|
if (flags & SO_OBJECTS)
|
|
x = count_partial(n);
|
|
else
|
|
x = n->nr_partial;
|
|
total += x;
|
|
nodes[node] += x;
|
|
}
|
|
|
|
if (flags & SO_FULL) {
|
|
int full_slabs = atomic_read(&n->nr_slabs)
|
|
- per_cpu[node]
|
|
- n->nr_partial;
|
|
|
|
if (flags & SO_OBJECTS)
|
|
x = full_slabs * s->objects;
|
|
else
|
|
x = full_slabs;
|
|
total += x;
|
|
nodes[node] += x;
|
|
}
|
|
}
|
|
|
|
x = sprintf(buf, "%lu", total);
|
|
#ifdef CONFIG_NUMA
|
|
for_each_online_node(node)
|
|
if (nodes[node])
|
|
x += sprintf(buf + x, " N%d=%lu",
|
|
node, nodes[node]);
|
|
#endif
|
|
kfree(nodes);
|
|
return x + sprintf(buf + x, "\n");
|
|
}
|
|
|
|
static int any_slab_objects(struct kmem_cache *s)
|
|
{
|
|
int node;
|
|
int cpu;
|
|
|
|
for_each_possible_cpu(cpu)
|
|
if (s->cpu_slab[cpu])
|
|
return 1;
|
|
|
|
for_each_node(node) {
|
|
struct kmem_cache_node *n = get_node(s, node);
|
|
|
|
if (n->nr_partial || atomic_read(&n->nr_slabs))
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
#define to_slab_attr(n) container_of(n, struct slab_attribute, attr)
|
|
#define to_slab(n) container_of(n, struct kmem_cache, kobj);
|
|
|
|
struct slab_attribute {
|
|
struct attribute attr;
|
|
ssize_t (*show)(struct kmem_cache *s, char *buf);
|
|
ssize_t (*store)(struct kmem_cache *s, const char *x, size_t count);
|
|
};
|
|
|
|
#define SLAB_ATTR_RO(_name) \
|
|
static struct slab_attribute _name##_attr = __ATTR_RO(_name)
|
|
|
|
#define SLAB_ATTR(_name) \
|
|
static struct slab_attribute _name##_attr = \
|
|
__ATTR(_name, 0644, _name##_show, _name##_store)
|
|
|
|
static ssize_t slab_size_show(struct kmem_cache *s, char *buf)
|
|
{
|
|
return sprintf(buf, "%d\n", s->size);
|
|
}
|
|
SLAB_ATTR_RO(slab_size);
|
|
|
|
static ssize_t align_show(struct kmem_cache *s, char *buf)
|
|
{
|
|
return sprintf(buf, "%d\n", s->align);
|
|
}
|
|
SLAB_ATTR_RO(align);
|
|
|
|
static ssize_t object_size_show(struct kmem_cache *s, char *buf)
|
|
{
|
|
return sprintf(buf, "%d\n", s->objsize);
|
|
}
|
|
SLAB_ATTR_RO(object_size);
|
|
|
|
static ssize_t objs_per_slab_show(struct kmem_cache *s, char *buf)
|
|
{
|
|
return sprintf(buf, "%d\n", s->objects);
|
|
}
|
|
SLAB_ATTR_RO(objs_per_slab);
|
|
|
|
static ssize_t order_show(struct kmem_cache *s, char *buf)
|
|
{
|
|
return sprintf(buf, "%d\n", s->order);
|
|
}
|
|
SLAB_ATTR_RO(order);
|
|
|
|
static ssize_t ctor_show(struct kmem_cache *s, char *buf)
|
|
{
|
|
if (s->ctor) {
|
|
int n = sprint_symbol(buf, (unsigned long)s->ctor);
|
|
|
|
return n + sprintf(buf + n, "\n");
|
|
}
|
|
return 0;
|
|
}
|
|
SLAB_ATTR_RO(ctor);
|
|
|
|
static ssize_t aliases_show(struct kmem_cache *s, char *buf)
|
|
{
|
|
return sprintf(buf, "%d\n", s->refcount - 1);
|
|
}
|
|
SLAB_ATTR_RO(aliases);
|
|
|
|
static ssize_t slabs_show(struct kmem_cache *s, char *buf)
|
|
{
|
|
return slab_objects(s, buf, SO_FULL|SO_PARTIAL|SO_CPU);
|
|
}
|
|
SLAB_ATTR_RO(slabs);
|
|
|
|
static ssize_t partial_show(struct kmem_cache *s, char *buf)
|
|
{
|
|
return slab_objects(s, buf, SO_PARTIAL);
|
|
}
|
|
SLAB_ATTR_RO(partial);
|
|
|
|
static ssize_t cpu_slabs_show(struct kmem_cache *s, char *buf)
|
|
{
|
|
return slab_objects(s, buf, SO_CPU);
|
|
}
|
|
SLAB_ATTR_RO(cpu_slabs);
|
|
|
|
static ssize_t objects_show(struct kmem_cache *s, char *buf)
|
|
{
|
|
return slab_objects(s, buf, SO_FULL|SO_PARTIAL|SO_CPU|SO_OBJECTS);
|
|
}
|
|
SLAB_ATTR_RO(objects);
|
|
|
|
static ssize_t sanity_checks_show(struct kmem_cache *s, char *buf)
|
|
{
|
|
return sprintf(buf, "%d\n", !!(s->flags & SLAB_DEBUG_FREE));
|
|
}
|
|
|
|
static ssize_t sanity_checks_store(struct kmem_cache *s,
|
|
const char *buf, size_t length)
|
|
{
|
|
s->flags &= ~SLAB_DEBUG_FREE;
|
|
if (buf[0] == '1')
|
|
s->flags |= SLAB_DEBUG_FREE;
|
|
return length;
|
|
}
|
|
SLAB_ATTR(sanity_checks);
|
|
|
|
static ssize_t trace_show(struct kmem_cache *s, char *buf)
|
|
{
|
|
return sprintf(buf, "%d\n", !!(s->flags & SLAB_TRACE));
|
|
}
|
|
|
|
static ssize_t trace_store(struct kmem_cache *s, const char *buf,
|
|
size_t length)
|
|
{
|
|
s->flags &= ~SLAB_TRACE;
|
|
if (buf[0] == '1')
|
|
s->flags |= SLAB_TRACE;
|
|
return length;
|
|
}
|
|
SLAB_ATTR(trace);
|
|
|
|
static ssize_t reclaim_account_show(struct kmem_cache *s, char *buf)
|
|
{
|
|
return sprintf(buf, "%d\n", !!(s->flags & SLAB_RECLAIM_ACCOUNT));
|
|
}
|
|
|
|
static ssize_t reclaim_account_store(struct kmem_cache *s,
|
|
const char *buf, size_t length)
|
|
{
|
|
s->flags &= ~SLAB_RECLAIM_ACCOUNT;
|
|
if (buf[0] == '1')
|
|
s->flags |= SLAB_RECLAIM_ACCOUNT;
|
|
return length;
|
|
}
|
|
SLAB_ATTR(reclaim_account);
|
|
|
|
static ssize_t hwcache_align_show(struct kmem_cache *s, char *buf)
|
|
{
|
|
return sprintf(buf, "%d\n", !!(s->flags & SLAB_HWCACHE_ALIGN));
|
|
}
|
|
SLAB_ATTR_RO(hwcache_align);
|
|
|
|
#ifdef CONFIG_ZONE_DMA
|
|
static ssize_t cache_dma_show(struct kmem_cache *s, char *buf)
|
|
{
|
|
return sprintf(buf, "%d\n", !!(s->flags & SLAB_CACHE_DMA));
|
|
}
|
|
SLAB_ATTR_RO(cache_dma);
|
|
#endif
|
|
|
|
static ssize_t destroy_by_rcu_show(struct kmem_cache *s, char *buf)
|
|
{
|
|
return sprintf(buf, "%d\n", !!(s->flags & SLAB_DESTROY_BY_RCU));
|
|
}
|
|
SLAB_ATTR_RO(destroy_by_rcu);
|
|
|
|
static ssize_t red_zone_show(struct kmem_cache *s, char *buf)
|
|
{
|
|
return sprintf(buf, "%d\n", !!(s->flags & SLAB_RED_ZONE));
|
|
}
|
|
|
|
static ssize_t red_zone_store(struct kmem_cache *s,
|
|
const char *buf, size_t length)
|
|
{
|
|
if (any_slab_objects(s))
|
|
return -EBUSY;
|
|
|
|
s->flags &= ~SLAB_RED_ZONE;
|
|
if (buf[0] == '1')
|
|
s->flags |= SLAB_RED_ZONE;
|
|
calculate_sizes(s);
|
|
return length;
|
|
}
|
|
SLAB_ATTR(red_zone);
|
|
|
|
static ssize_t poison_show(struct kmem_cache *s, char *buf)
|
|
{
|
|
return sprintf(buf, "%d\n", !!(s->flags & SLAB_POISON));
|
|
}
|
|
|
|
static ssize_t poison_store(struct kmem_cache *s,
|
|
const char *buf, size_t length)
|
|
{
|
|
if (any_slab_objects(s))
|
|
return -EBUSY;
|
|
|
|
s->flags &= ~SLAB_POISON;
|
|
if (buf[0] == '1')
|
|
s->flags |= SLAB_POISON;
|
|
calculate_sizes(s);
|
|
return length;
|
|
}
|
|
SLAB_ATTR(poison);
|
|
|
|
static ssize_t store_user_show(struct kmem_cache *s, char *buf)
|
|
{
|
|
return sprintf(buf, "%d\n", !!(s->flags & SLAB_STORE_USER));
|
|
}
|
|
|
|
static ssize_t store_user_store(struct kmem_cache *s,
|
|
const char *buf, size_t length)
|
|
{
|
|
if (any_slab_objects(s))
|
|
return -EBUSY;
|
|
|
|
s->flags &= ~SLAB_STORE_USER;
|
|
if (buf[0] == '1')
|
|
s->flags |= SLAB_STORE_USER;
|
|
calculate_sizes(s);
|
|
return length;
|
|
}
|
|
SLAB_ATTR(store_user);
|
|
|
|
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 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') {
|
|
int rc = kmem_cache_shrink(s);
|
|
|
|
if (rc)
|
|
return rc;
|
|
} else
|
|
return -EINVAL;
|
|
return length;
|
|
}
|
|
SLAB_ATTR(shrink);
|
|
|
|
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);
|
|
|
|
#ifdef CONFIG_NUMA
|
|
static ssize_t defrag_ratio_show(struct kmem_cache *s, char *buf)
|
|
{
|
|
return sprintf(buf, "%d\n", s->defrag_ratio / 10);
|
|
}
|
|
|
|
static ssize_t defrag_ratio_store(struct kmem_cache *s,
|
|
const char *buf, size_t length)
|
|
{
|
|
int n = simple_strtoul(buf, NULL, 10);
|
|
|
|
if (n < 100)
|
|
s->defrag_ratio = n * 10;
|
|
return length;
|
|
}
|
|
SLAB_ATTR(defrag_ratio);
|
|
#endif
|
|
|
|
static struct attribute * slab_attrs[] = {
|
|
&slab_size_attr.attr,
|
|
&object_size_attr.attr,
|
|
&objs_per_slab_attr.attr,
|
|
&order_attr.attr,
|
|
&objects_attr.attr,
|
|
&slabs_attr.attr,
|
|
&partial_attr.attr,
|
|
&cpu_slabs_attr.attr,
|
|
&ctor_attr.attr,
|
|
&aliases_attr.attr,
|
|
&align_attr.attr,
|
|
&sanity_checks_attr.attr,
|
|
&trace_attr.attr,
|
|
&hwcache_align_attr.attr,
|
|
&reclaim_account_attr.attr,
|
|
&destroy_by_rcu_attr.attr,
|
|
&red_zone_attr.attr,
|
|
&poison_attr.attr,
|
|
&store_user_attr.attr,
|
|
&validate_attr.attr,
|
|
&shrink_attr.attr,
|
|
&alloc_calls_attr.attr,
|
|
&free_calls_attr.attr,
|
|
#ifdef CONFIG_ZONE_DMA
|
|
&cache_dma_attr.attr,
|
|
#endif
|
|
#ifdef CONFIG_NUMA
|
|
&defrag_ratio_attr.attr,
|
|
#endif
|
|
NULL
|
|
};
|
|
|
|
static struct attribute_group slab_attr_group = {
|
|
.attrs = slab_attrs,
|
|
};
|
|
|
|
static ssize_t slab_attr_show(struct kobject *kobj,
|
|
struct attribute *attr,
|
|
char *buf)
|
|
{
|
|
struct slab_attribute *attribute;
|
|
struct kmem_cache *s;
|
|
int err;
|
|
|
|
attribute = to_slab_attr(attr);
|
|
s = to_slab(kobj);
|
|
|
|
if (!attribute->show)
|
|
return -EIO;
|
|
|
|
err = attribute->show(s, buf);
|
|
|
|
return err;
|
|
}
|
|
|
|
static ssize_t slab_attr_store(struct kobject *kobj,
|
|
struct attribute *attr,
|
|
const char *buf, size_t len)
|
|
{
|
|
struct slab_attribute *attribute;
|
|
struct kmem_cache *s;
|
|
int err;
|
|
|
|
attribute = to_slab_attr(attr);
|
|
s = to_slab(kobj);
|
|
|
|
if (!attribute->store)
|
|
return -EIO;
|
|
|
|
err = attribute->store(s, buf, len);
|
|
|
|
return err;
|
|
}
|
|
|
|
static struct sysfs_ops slab_sysfs_ops = {
|
|
.show = slab_attr_show,
|
|
.store = slab_attr_store,
|
|
};
|
|
|
|
static struct kobj_type slab_ktype = {
|
|
.sysfs_ops = &slab_sysfs_ops,
|
|
};
|
|
|
|
static int uevent_filter(struct kset *kset, struct kobject *kobj)
|
|
{
|
|
struct kobj_type *ktype = get_ktype(kobj);
|
|
|
|
if (ktype == &slab_ktype)
|
|
return 1;
|
|
return 0;
|
|
}
|
|
|
|
static struct kset_uevent_ops slab_uevent_ops = {
|
|
.filter = uevent_filter,
|
|
};
|
|
|
|
static decl_subsys(slab, &slab_ktype, &slab_uevent_ops);
|
|
|
|
#define ID_STR_LENGTH 64
|
|
|
|
/* Create a unique string id for a slab cache:
|
|
* format
|
|
* :[flags-]size:[memory address of kmemcache]
|
|
*/
|
|
static char *create_unique_id(struct kmem_cache *s)
|
|
{
|
|
char *name = kmalloc(ID_STR_LENGTH, GFP_KERNEL);
|
|
char *p = name;
|
|
|
|
BUG_ON(!name);
|
|
|
|
*p++ = ':';
|
|
/*
|
|
* First flags affecting slabcache operations. We will only
|
|
* get here for aliasable slabs so we do not need to support
|
|
* too many flags. The flags here must cover all flags that
|
|
* are matched during merging to guarantee that the id is
|
|
* unique.
|
|
*/
|
|
if (s->flags & SLAB_CACHE_DMA)
|
|
*p++ = 'd';
|
|
if (s->flags & SLAB_RECLAIM_ACCOUNT)
|
|
*p++ = 'a';
|
|
if (s->flags & SLAB_DEBUG_FREE)
|
|
*p++ = 'F';
|
|
if (p != name + 1)
|
|
*p++ = '-';
|
|
p += sprintf(p, "%07d", s->size);
|
|
BUG_ON(p > name + ID_STR_LENGTH - 1);
|
|
return name;
|
|
}
|
|
|
|
static int sysfs_slab_add(struct kmem_cache *s)
|
|
{
|
|
int err;
|
|
const char *name;
|
|
int unmergeable;
|
|
|
|
if (slab_state < SYSFS)
|
|
/* Defer until later */
|
|
return 0;
|
|
|
|
unmergeable = slab_unmergeable(s);
|
|
if (unmergeable) {
|
|
/*
|
|
* Slabcache can never be merged so we can use the name proper.
|
|
* This is typically the case for debug situations. In that
|
|
* case we can catch duplicate names easily.
|
|
*/
|
|
sysfs_remove_link(&slab_subsys.kobj, s->name);
|
|
name = s->name;
|
|
} else {
|
|
/*
|
|
* Create a unique name for the slab as a target
|
|
* for the symlinks.
|
|
*/
|
|
name = create_unique_id(s);
|
|
}
|
|
|
|
kobj_set_kset_s(s, slab_subsys);
|
|
kobject_set_name(&s->kobj, name);
|
|
kobject_init(&s->kobj);
|
|
err = kobject_add(&s->kobj);
|
|
if (err)
|
|
return err;
|
|
|
|
err = sysfs_create_group(&s->kobj, &slab_attr_group);
|
|
if (err)
|
|
return err;
|
|
kobject_uevent(&s->kobj, KOBJ_ADD);
|
|
if (!unmergeable) {
|
|
/* Setup first alias */
|
|
sysfs_slab_alias(s, s->name);
|
|
kfree(name);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static void sysfs_slab_remove(struct kmem_cache *s)
|
|
{
|
|
kobject_uevent(&s->kobj, KOBJ_REMOVE);
|
|
kobject_del(&s->kobj);
|
|
}
|
|
|
|
/*
|
|
* Need to buffer aliases during bootup until sysfs becomes
|
|
* available lest we loose that information.
|
|
*/
|
|
struct saved_alias {
|
|
struct kmem_cache *s;
|
|
const char *name;
|
|
struct saved_alias *next;
|
|
};
|
|
|
|
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 == SYSFS) {
|
|
/*
|
|
* If we have a leftover link then remove it.
|
|
*/
|
|
sysfs_remove_link(&slab_subsys.kobj, name);
|
|
return sysfs_create_link(&slab_subsys.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;
|
|
|
|
err = subsystem_register(&slab_subsys);
|
|
if (err) {
|
|
printk(KERN_ERR "Cannot register slab subsystem.\n");
|
|
return -ENOSYS;
|
|
}
|
|
|
|
slab_state = SYSFS;
|
|
|
|
list_for_each_entry(s, &slab_caches, list) {
|
|
err = sysfs_slab_add(s);
|
|
BUG_ON(err);
|
|
}
|
|
|
|
while (alias_list) {
|
|
struct saved_alias *al = alias_list;
|
|
|
|
alias_list = alias_list->next;
|
|
err = sysfs_slab_alias(al->s, al->name);
|
|
BUG_ON(err);
|
|
kfree(al);
|
|
}
|
|
|
|
resiliency_test();
|
|
return 0;
|
|
}
|
|
|
|
__initcall(slab_sysfs_init);
|
|
#endif
|