FreeBSD/Linux Kernel Cross Reference
sys/mm/slab.h

     #ifndef MM_SLAB_H
     #define MM_SLAB_H
     /*
      * Internal slab definitions
      */
     
     /*
      * 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_ARRAYCACHE,     /* SLAB: kmalloc size for arraycache available */
            PARTIAL_L3,             /* SLAB: kmalloc size for l3 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;
    
    unsigned long calculate_alignment(unsigned long flags,
                    unsigned long align, unsigned long size);
    
    /* Functions provided by the slab allocators */
    extern int __kmem_cache_create(struct kmem_cache *, unsigned long flags);
    
    extern struct kmem_cache *create_kmalloc_cache(const char *name, size_t size,
                            unsigned long flags);
    extern void create_boot_cache(struct kmem_cache *, const char *name,
                            size_t size, unsigned long flags);
    
    struct mem_cgroup;
    #ifdef CONFIG_SLUB
    struct kmem_cache *
    __kmem_cache_alias(struct mem_cgroup *memcg, const char *name, size_t size,
                       size_t align, unsigned long flags, void (*ctor)(void *));
    #else
    static inline struct kmem_cache *
    __kmem_cache_alias(struct mem_cgroup *memcg, const char *name, size_t size,
                       size_t align, unsigned long flags, void (*ctor)(void *))
    { return NULL; }
    #endif
    
    
    /* Legal flag mask for kmem_cache_create(), for various configurations */
    #define SLAB_CORE_FLAGS (SLAB_HWCACHE_ALIGN | SLAB_CACHE_DMA | SLAB_PANIC | \
                             SLAB_DESTROY_BY_RCU | SLAB_DEBUG_OBJECTS )
    
    #if defined(CONFIG_DEBUG_SLAB)
    #define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
    #elif defined(CONFIG_SLUB_DEBUG)
    #define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
                              SLAB_TRACE | SLAB_DEBUG_FREE)
    #else
    #define SLAB_DEBUG_FLAGS (0)
    #endif
    
    #if defined(CONFIG_SLAB)
    #define SLAB_CACHE_FLAGS (SLAB_MEM_SPREAD | SLAB_NOLEAKTRACE | \
                              SLAB_RECLAIM_ACCOUNT | SLAB_TEMPORARY | SLAB_NOTRACK)
    #elif defined(CONFIG_SLUB)
    #define SLAB_CACHE_FLAGS (SLAB_NOLEAKTRACE | SLAB_RECLAIM_ACCOUNT | \
                              SLAB_TEMPORARY | SLAB_NOTRACK)
    #else
    #define SLAB_CACHE_FLAGS (0)
    #endif
    
    #define CACHE_CREATE_MASK (SLAB_CORE_FLAGS | SLAB_DEBUG_FLAGS | SLAB_CACHE_FLAGS)
    
    int __kmem_cache_shutdown(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_MEMCG_KMEM
   static inline bool is_root_cache(struct kmem_cache *s)
   {
           return !s->memcg_params || s->memcg_params->is_root_cache;
   }
   
   static inline bool cache_match_memcg(struct kmem_cache *cachep,
                                        struct mem_cgroup *memcg)
   {
           return (is_root_cache(cachep) && !memcg) ||
                                   (cachep->memcg_params->memcg == memcg);
   }
   
   static inline void memcg_bind_pages(struct kmem_cache *s, int order)
   {
           if (!is_root_cache(s))
                   atomic_add(1 << order, &s->memcg_params->nr_pages);
   }
   
   static inline void memcg_release_pages(struct kmem_cache *s, int order)
   {
           if (is_root_cache(s))
                   return;
   
           if (atomic_sub_and_test((1 << order), &s->memcg_params->nr_pages))
                   mem_cgroup_destroy_cache(s);
   }
   
   static inline bool slab_equal_or_root(struct kmem_cache *s,
                                           struct kmem_cache *p)
   {
           return (p == s) ||
                   (s->memcg_params && (p == s->memcg_params->root_cache));
   }
   
   /*
    * We use suffixes to the name in memcg because we can't have caches
    * created in the system with the same name. But when we print them
    * locally, better refer to them with the base name
    */
   static inline const char *cache_name(struct kmem_cache *s)
   {
           if (!is_root_cache(s))
                   return s->memcg_params->root_cache->name;
           return s->name;
   }
   
   static inline struct kmem_cache *cache_from_memcg(struct kmem_cache *s, int idx)
   {
           return s->memcg_params->memcg_caches[idx];
   }
   
   static inline struct kmem_cache *memcg_root_cache(struct kmem_cache *s)
   {
           if (is_root_cache(s))
                   return s;
           return s->memcg_params->root_cache;
   }
   #else
   static inline bool is_root_cache(struct kmem_cache *s)
   {
           return true;
   }
   
   static inline bool cache_match_memcg(struct kmem_cache *cachep,
                                        struct mem_cgroup *memcg)
   {
           return true;
   }
   
   static inline void memcg_bind_pages(struct kmem_cache *s, int order)
   {
   }
   
   static inline void memcg_release_pages(struct kmem_cache *s, int order)
   {
   }
   
   static inline bool slab_equal_or_root(struct kmem_cache *s,
                                         struct kmem_cache *p)
   {
           return true;
   }
   
   static inline const char *cache_name(struct kmem_cache *s)
   {
           return s->name;
   }
   
   static inline struct kmem_cache *cache_from_memcg(struct kmem_cache *s, int idx)
   {
           return NULL;
   }
   
   static inline struct kmem_cache *memcg_root_cache(struct kmem_cache *s)
   {
           return s;
   }
   #endif
   
   static inline struct kmem_cache *cache_from_obj(struct kmem_cache *s, void *x)
   {
           struct kmem_cache *cachep;
           struct page *page;
   
           /*
            * When kmemcg is not being used, both assignments should return the
            * same value. but we don't want to pay the assignment price in that
            * case. If it is not compiled in, the compiler should be smart enough
            * to not do even the assignment. In that case, slab_equal_or_root
            * will also be a constant.
            */
           if (!memcg_kmem_enabled() && !unlikely(s->flags & SLAB_DEBUG_FREE))
                   return s;
   
           page = virt_to_head_page(x);
           cachep = page->slab_cache;
           if (slab_equal_or_root(cachep, s))
                   return cachep;
   
           pr_err("%s: Wrong slab cache. %s but object is from %s\n",
                   __FUNCTION__, cachep->name, s->name);
           WARN_ON_ONCE(1);
           return s;
   }
   #endif

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