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b774d3e326
linux/mm/slab.h
Vlastimil Babka b774d3e326 mm/slab: move kfree() from slab_common.c to slub.c 
This should result in better code. Currently kfree() makes a function
call between compilation units to __kmem_cache_free() which does its own
virt_to_slab(), throwing away the struct slab pointer we already had in
kfree(). Now it can be reused. Additionally kfree() can now inline the
whole SLUB freeing fastpath.

Also move over free_large_kmalloc() as the only callsites are now in
slub.c, and make it static.

Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: David Rientjes <rientjes@google.com>
Tested-by: David Rientjes <rientjes@google.com>
Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
2023-12-06 11:57:21 +01:00

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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef MM_SLAB_H
#define MM_SLAB_H
#include <linux/reciprocal_div.h>
#include <linux/list_lru.h>
#include <linux/local_lock.h>
#include <linux/random.h>
#include <linux/kobject.h>
#include <linux/sched/mm.h>
#include <linux/memcontrol.h>
#include <linux/kfence.h>
#include <linux/kasan.h>
/*
* Internal slab definitions
*/
#ifdef CONFIG_64BIT
# ifdef system_has_cmpxchg128
# define system_has_freelist_aba() system_has_cmpxchg128()
# define try_cmpxchg_freelist try_cmpxchg128
# endif
#define this_cpu_try_cmpxchg_freelist this_cpu_try_cmpxchg128
typedef u128 freelist_full_t;
#else /* CONFIG_64BIT */
# ifdef system_has_cmpxchg64
# define system_has_freelist_aba() system_has_cmpxchg64()
# define try_cmpxchg_freelist try_cmpxchg64
# endif
#define this_cpu_try_cmpxchg_freelist this_cpu_try_cmpxchg64
typedef u64 freelist_full_t;
#endif /* CONFIG_64BIT */
#if defined(system_has_freelist_aba) && !defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
#undef system_has_freelist_aba
#endif
/*
* Freelist pointer and counter to cmpxchg together, avoids the typical ABA
* problems with cmpxchg of just a pointer.
*/
typedef union {
struct {
void *freelist;
unsigned long counter;
};
freelist_full_t full;
} freelist_aba_t;
/* Reuses the bits in struct page */
struct slab {
unsigned long __page_flags;
struct kmem_cache *slab_cache;
union {
struct {
union {
struct list_head slab_list;
#ifdef CONFIG_SLUB_CPU_PARTIAL
struct {
struct slab *next;
int slabs; /* Nr of slabs left */
};
#endif
};
/* Double-word boundary */
union {
struct {
void *freelist; /* first free object */
union {
unsigned long counters;
struct {
unsigned inuse:16;
unsigned objects:15;
unsigned frozen:1;
};
};
};
#ifdef system_has_freelist_aba
freelist_aba_t freelist_counter;
#endif
};
};
struct rcu_head rcu_head;
};
unsigned int __unused;
atomic_t __page_refcount;
#ifdef CONFIG_MEMCG
unsigned long memcg_data;
#endif
};
#define SLAB_MATCH(pg, sl) \
static_assert(offsetof(struct page, pg) == offsetof(struct slab, sl))
SLAB_MATCH(flags, __page_flags);
SLAB_MATCH(compound_head, slab_cache); /* Ensure bit 0 is clear */
SLAB_MATCH(_refcount, __page_refcount);
#ifdef CONFIG_MEMCG
SLAB_MATCH(memcg_data, memcg_data);
#endif
#undef SLAB_MATCH
static_assert(sizeof(struct slab) <= sizeof(struct page));
#if defined(system_has_freelist_aba)
static_assert(IS_ALIGNED(offsetof(struct slab, freelist), sizeof(freelist_aba_t)));
#endif
/**
* folio_slab - Converts from folio to slab.
* @folio: The folio.
*
* Currently struct slab is a different representation of a folio where
* folio_test_slab() is true.
*
* Return: The slab which contains this folio.
*/
#define folio_slab(folio) (_Generic((folio), \
const struct folio *: (const struct slab *)(folio), \
struct folio *: (struct slab *)(folio)))
/**
* slab_folio - The folio allocated for a slab
* @slab: The slab.
*
* Slabs are allocated as folios that contain the individual objects and are
* using some fields in the first struct page of the folio - those fields are
* now accessed by struct slab. It is occasionally necessary to convert back to
* a folio in order to communicate with the rest of the mm. Please use this
* helper function instead of casting yourself, as the implementation may change
* in the future.
*/
#define slab_folio(s) (_Generic((s), \
const struct slab *: (const struct folio *)s, \
struct slab *: (struct folio *)s))
/**
* page_slab - Converts from first struct page to slab.
* @p: The first (either head of compound or single) page of slab.
*
* A temporary wrapper to convert struct page to struct slab in situations where
* we know the page is the compound head, or single order-0 page.
*
* Long-term ideally everything would work with struct slab directly or go
* through folio to struct slab.
*
* Return: The slab which contains this page
*/
#define page_slab(p) (_Generic((p), \
const struct page *: (const struct slab *)(p), \
struct page *: (struct slab *)(p)))
/**
* slab_page - The first struct page allocated for a slab
* @slab: The slab.
*
* A convenience wrapper for converting slab to the first struct page of the
* underlying folio, to communicate with code not yet converted to folio or
* struct slab.
*/
#define slab_page(s) folio_page(slab_folio(s), 0)
/*
* If network-based swap is enabled, sl*b must keep track of whether pages
* were allocated from pfmemalloc reserves.
*/
static inline bool slab_test_pfmemalloc(const struct slab *slab)
{
return folio_test_active((struct folio *)slab_folio(slab));
}
static inline void slab_set_pfmemalloc(struct slab *slab)
{
folio_set_active(slab_folio(slab));
}
static inline void slab_clear_pfmemalloc(struct slab *slab)
{
folio_clear_active(slab_folio(slab));
}
static inline void __slab_clear_pfmemalloc(struct slab *slab)
{
__folio_clear_active(slab_folio(slab));
}
static inline void *slab_address(const struct slab *slab)
{
return folio_address(slab_folio(slab));
}
static inline int slab_nid(const struct slab *slab)
{
return folio_nid(slab_folio(slab));
}
static inline pg_data_t *slab_pgdat(const struct slab *slab)
{
return folio_pgdat(slab_folio(slab));
}
static inline struct slab *virt_to_slab(const void *addr)
{
struct folio *folio = virt_to_folio(addr);
if (!folio_test_slab(folio))
return NULL;
return folio_slab(folio);
}
static inline int slab_order(const struct slab *slab)
{
return folio_order((struct folio *)slab_folio(slab));
}
static inline size_t slab_size(const struct slab *slab)
{
return PAGE_SIZE << slab_order(slab);
}
#ifdef CONFIG_SLUB_CPU_PARTIAL
#define slub_percpu_partial(c) ((c)->partial)
#define slub_set_percpu_partial(c, p) \
({ \
slub_percpu_partial(c) = (p)->next; \
})
#define slub_percpu_partial_read_once(c) READ_ONCE(slub_percpu_partial(c))
#else
#define slub_percpu_partial(c) NULL
#define slub_set_percpu_partial(c, p)
#define slub_percpu_partial_read_once(c) NULL
#endif // CONFIG_SLUB_CPU_PARTIAL
/*
* Word size structure that can be atomically updated or read and that
* contains both the order and the number of objects that a slab of the
* given order would contain.
*/
struct kmem_cache_order_objects {
unsigned int x;
};
/*
* Slab cache management.
*/
struct kmem_cache {
#ifndef CONFIG_SLUB_TINY
struct kmem_cache_cpu __percpu *cpu_slab;
#endif
/* Used for retrieving partial slabs, etc. */
slab_flags_t flags;
unsigned long min_partial;
unsigned int size; /* Object size including metadata */
unsigned int object_size; /* Object size without metadata */
struct reciprocal_value reciprocal_size;
unsigned int offset; /* Free pointer offset */
#ifdef CONFIG_SLUB_CPU_PARTIAL
/* Number of per cpu partial objects to keep around */
unsigned int cpu_partial;
/* Number of per cpu partial slabs to keep around */
unsigned int cpu_partial_slabs;
#endif
struct kmem_cache_order_objects oo;
/* Allocation and freeing of slabs */
struct kmem_cache_order_objects min;
gfp_t allocflags; /* gfp flags to use on each alloc */
int refcount; /* Refcount for slab cache destroy */
void (*ctor)(void *object); /* Object constructor */
unsigned int inuse; /* Offset to metadata */
unsigned int align; /* Alignment */
unsigned int red_left_pad; /* Left redzone padding size */
const char *name; /* Name (only for display!) */
struct list_head list; /* List of slab caches */
#ifdef CONFIG_SYSFS
struct kobject kobj; /* For sysfs */
#endif
#ifdef CONFIG_SLAB_FREELIST_HARDENED
unsigned long random;
#endif
#ifdef CONFIG_NUMA
/*
* Defragmentation by allocating from a remote node.
*/
unsigned int remote_node_defrag_ratio;
#endif
#ifdef CONFIG_SLAB_FREELIST_RANDOM
unsigned int *random_seq;
#endif
#ifdef CONFIG_KASAN_GENERIC
struct kasan_cache kasan_info;
#endif
#ifdef CONFIG_HARDENED_USERCOPY
unsigned int useroffset; /* Usercopy region offset */
unsigned int usersize; /* Usercopy region size */
#endif
struct kmem_cache_node *node[MAX_NUMNODES];
};
#if defined(CONFIG_SYSFS) && !defined(CONFIG_SLUB_TINY)
#define SLAB_SUPPORTS_SYSFS
void sysfs_slab_unlink(struct kmem_cache *s);
void sysfs_slab_release(struct kmem_cache *s);
#else
static inline void sysfs_slab_unlink(struct kmem_cache *s) { }
static inline void sysfs_slab_release(struct kmem_cache *s) { }
#endif
void *fixup_red_left(struct kmem_cache *s, void *p);
static inline void *nearest_obj(struct kmem_cache *cache,
const struct slab *slab, void *x)
{
void *object = x - (x - slab_address(slab)) % cache->size;
void *last_object = slab_address(slab) +
(slab->objects - 1) * cache->size;
void *result = (unlikely(object > last_object)) ? last_object : object;
result = fixup_red_left(cache, result);
return result;
}
/* Determine object index from a given position */
static inline unsigned int __obj_to_index(const struct kmem_cache *cache,
void *addr, void *obj)
{
return reciprocal_divide(kasan_reset_tag(obj) - addr,
cache->reciprocal_size);
}
static inline unsigned int obj_to_index(const struct kmem_cache *cache,
const struct slab *slab, void *obj)
{
if (is_kfence_address(obj))
return 0;
return __obj_to_index(cache, slab_address(slab), obj);
}
static inline int objs_per_slab(const struct kmem_cache *cache,
const struct slab *slab)
{
return slab->objects;
}
/*
* State of the slab allocator.
*
* This is used to describe the states of the allocator during bootup.
* Allocators use this to gradually bootstrap themselves. Most allocators
* have the problem that the structures used for managing slab caches are
* allocated from slab caches themselves.
*/
enum slab_state {
DOWN, /* No slab functionality yet */
PARTIAL, /* SLUB: kmem_cache_node available */
PARTIAL_NODE, /* SLAB: kmalloc size for node struct available */
UP, /* Slab caches usable but not all extras yet */
FULL /* Everything is working */
};
extern enum slab_state slab_state;
/* The slab cache mutex protects the management structures during changes */
extern struct mutex slab_mutex;
/* The list of all slab caches on the system */
extern struct list_head slab_caches;
/* The slab cache that manages slab cache information */
extern struct kmem_cache *kmem_cache;
/* A table of kmalloc cache names and sizes */
extern const struct kmalloc_info_struct {
const char *name[NR_KMALLOC_TYPES];
unsigned int size;
} kmalloc_info[];
/* Kmalloc array related functions */
void setup_kmalloc_cache_index_table(void);
void create_kmalloc_caches(slab_flags_t);
/* Find the kmalloc slab corresponding for a certain size */
struct kmem_cache *kmalloc_slab(size_t size, gfp_t flags, unsigned long caller);
void *__kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags,
int node, size_t orig_size,
unsigned long caller);
gfp_t kmalloc_fix_flags(gfp_t flags);
/* Functions provided by the slab allocators */
int __kmem_cache_create(struct kmem_cache *, slab_flags_t flags);
void __init kmem_cache_init(void);
void __init new_kmalloc_cache(int idx, enum kmalloc_cache_type type,
slab_flags_t flags);
extern void create_boot_cache(struct kmem_cache *, const char *name,
unsigned int size, slab_flags_t flags,
unsigned int useroffset, unsigned int usersize);
int slab_unmergeable(struct kmem_cache *s);
struct kmem_cache *find_mergeable(unsigned size, unsigned align,
slab_flags_t flags, const char *name, void (*ctor)(void *));
struct kmem_cache *
__kmem_cache_alias(const char *name, unsigned int size, unsigned int align,
slab_flags_t flags, void (*ctor)(void *));
slab_flags_t kmem_cache_flags(unsigned int object_size,
slab_flags_t flags, const char *name);
static inline bool is_kmalloc_cache(struct kmem_cache *s)
{
return (s->flags & SLAB_KMALLOC);
}
/* Legal flag mask for kmem_cache_create(), for various configurations */
#define SLAB_CORE_FLAGS (SLAB_HWCACHE_ALIGN | SLAB_CACHE_DMA | \
SLAB_CACHE_DMA32 | SLAB_PANIC | \
SLAB_TYPESAFE_BY_RCU | SLAB_DEBUG_OBJECTS )
#ifdef CONFIG_SLUB_DEBUG
#define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
SLAB_TRACE | SLAB_CONSISTENCY_CHECKS)
#else
#define SLAB_DEBUG_FLAGS (0)
#endif
#define SLAB_CACHE_FLAGS (SLAB_NOLEAKTRACE | SLAB_RECLAIM_ACCOUNT | \
SLAB_TEMPORARY | SLAB_ACCOUNT | \
SLAB_NO_USER_FLAGS | SLAB_KMALLOC | SLAB_NO_MERGE)
/* Common flags available with current configuration */
#define CACHE_CREATE_MASK (SLAB_CORE_FLAGS | SLAB_DEBUG_FLAGS | SLAB_CACHE_FLAGS)
/* Common flags permitted for kmem_cache_create */
#define SLAB_FLAGS_PERMITTED (SLAB_CORE_FLAGS | \
SLAB_RED_ZONE | \
SLAB_POISON | \
SLAB_STORE_USER | \
SLAB_TRACE | \
SLAB_CONSISTENCY_CHECKS | \
SLAB_MEM_SPREAD | \
SLAB_NOLEAKTRACE | \
SLAB_RECLAIM_ACCOUNT | \
SLAB_TEMPORARY | \
SLAB_ACCOUNT | \
SLAB_KMALLOC | \
SLAB_NO_MERGE | \
SLAB_NO_USER_FLAGS)
bool __kmem_cache_empty(struct kmem_cache *);
int __kmem_cache_shutdown(struct kmem_cache *);
void __kmem_cache_release(struct kmem_cache *);
int __kmem_cache_shrink(struct kmem_cache *);
void slab_kmem_cache_release(struct kmem_cache *);
struct seq_file;
struct file;
struct slabinfo {
unsigned long active_objs;
unsigned long num_objs;
unsigned long active_slabs;
unsigned long num_slabs;
unsigned long shared_avail;
unsigned int limit;
unsigned int batchcount;
unsigned int shared;
unsigned int objects_per_slab;
unsigned int cache_order;
};
void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo);
void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *s);
ssize_t slabinfo_write(struct file *file, const char __user *buffer,
size_t count, loff_t *ppos);
#ifdef CONFIG_SLUB_DEBUG
#ifdef CONFIG_SLUB_DEBUG_ON
DECLARE_STATIC_KEY_TRUE(slub_debug_enabled);
#else
DECLARE_STATIC_KEY_FALSE(slub_debug_enabled);
#endif
extern void print_tracking(struct kmem_cache *s, void *object);
long validate_slab_cache(struct kmem_cache *s);
static inline bool __slub_debug_enabled(void)
{
return static_branch_unlikely(&slub_debug_enabled);
}
#else
static inline void print_tracking(struct kmem_cache *s, void *object)
{
}
static inline bool __slub_debug_enabled(void)
{
return false;
}
#endif
/*
* Returns true if any of the specified slub_debug flags is enabled for the
* cache. Use only for flags parsed by setup_slub_debug() as it also enables
* the static key.
*/
static inline bool kmem_cache_debug_flags(struct kmem_cache *s, slab_flags_t flags)
{
if (IS_ENABLED(CONFIG_SLUB_DEBUG))
VM_WARN_ON_ONCE(!(flags & SLAB_DEBUG_FLAGS));
if (__slub_debug_enabled())
return s->flags & flags;
return false;
}
#ifdef CONFIG_MEMCG_KMEM
/*
* slab_objcgs - get the object cgroups vector associated with a slab
* @slab: a pointer to the slab struct
*
* Returns a pointer to the object cgroups vector associated with the slab,
* or NULL if no such vector has been associated yet.
*/
static inline struct obj_cgroup **slab_objcgs(struct slab *slab)
{
unsigned long memcg_data = READ_ONCE(slab->memcg_data);
VM_BUG_ON_PAGE(memcg_data && !(memcg_data & MEMCG_DATA_OBJCGS),
slab_page(slab));
VM_BUG_ON_PAGE(memcg_data & MEMCG_DATA_KMEM, slab_page(slab));
return (struct obj_cgroup **)(memcg_data & ~MEMCG_DATA_FLAGS_MASK);
}
int memcg_alloc_slab_cgroups(struct slab *slab, struct kmem_cache *s,
gfp_t gfp, bool new_slab);
void mod_objcg_state(struct obj_cgroup *objcg, struct pglist_data *pgdat,
enum node_stat_item idx, int nr);
#else /* CONFIG_MEMCG_KMEM */
static inline struct obj_cgroup **slab_objcgs(struct slab *slab)
{
return NULL;
}
static inline int memcg_alloc_slab_cgroups(struct slab *slab,
struct kmem_cache *s, gfp_t gfp,
bool new_slab)
{
return 0;
}
#endif /* CONFIG_MEMCG_KMEM */
size_t __ksize(const void *objp);
static inline size_t slab_ksize(const struct kmem_cache *s)
{
#ifdef CONFIG_SLUB_DEBUG
/*
* Debugging requires use of the padding between object
* and whatever may come after it.
*/
if (s->flags & (SLAB_RED_ZONE | SLAB_POISON))
return s->object_size;
#endif
if (s->flags & SLAB_KASAN)
return s->object_size;
/*
* 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_TYPESAFE_BY_RCU | SLAB_STORE_USER))
return s->inuse;
/*
* Else we can use all the padding etc for the allocation
*/
return s->size;
}
#ifdef CONFIG_SLUB_DEBUG
void dump_unreclaimable_slab(void);
#else
static inline void dump_unreclaimable_slab(void)
{
}
#endif
void ___cache_free(struct kmem_cache *cache, void *x, unsigned long addr);
#ifdef CONFIG_SLAB_FREELIST_RANDOM
int cache_random_seq_create(struct kmem_cache *cachep, unsigned int count,
gfp_t gfp);
void cache_random_seq_destroy(struct kmem_cache *cachep);
#else
static inline int cache_random_seq_create(struct kmem_cache *cachep,
unsigned int count, gfp_t gfp)
{
return 0;
}
static inline void cache_random_seq_destroy(struct kmem_cache *cachep) { }
#endif /* CONFIG_SLAB_FREELIST_RANDOM */
static inline bool slab_want_init_on_alloc(gfp_t flags, struct kmem_cache *c)
{
if (static_branch_maybe(CONFIG_INIT_ON_ALLOC_DEFAULT_ON,
&init_on_alloc)) {
if (c->ctor)
return false;
if (c->flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON))
return flags & __GFP_ZERO;
return true;
}
return flags & __GFP_ZERO;
}
static inline bool slab_want_init_on_free(struct kmem_cache *c)
{
if (static_branch_maybe(CONFIG_INIT_ON_FREE_DEFAULT_ON,
&init_on_free))
return !(c->ctor ||
(c->flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON)));
return false;
}
#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_SLUB_DEBUG)
void debugfs_slab_release(struct kmem_cache *);
#else
static inline void debugfs_slab_release(struct kmem_cache *s) { }
#endif
#ifdef CONFIG_PRINTK
#define KS_ADDRS_COUNT 16
struct kmem_obj_info {
void *kp_ptr;
struct slab *kp_slab;
void *kp_objp;
unsigned long kp_data_offset;
struct kmem_cache *kp_slab_cache;
void *kp_ret;
void *kp_stack[KS_ADDRS_COUNT];
void *kp_free_stack[KS_ADDRS_COUNT];
};
void __kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct slab *slab);
#endif
void __check_heap_object(const void *ptr, unsigned long n,
const struct slab *slab, bool to_user);
#ifdef CONFIG_SLUB_DEBUG
void skip_orig_size_check(struct kmem_cache *s, const void *object);
#endif
#endif /* MM_SLAB_H */
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