FreeBSD/Linux Kernel Cross Reference
sys/vm/uma.h

     /*-
      * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
      *
      * Copyright (c) 2002, 2003, 2004, 2005 Jeffrey Roberson <jeff@FreeBSD.org>
      * Copyright (c) 2004, 2005 Bosko Milekic <bmilekic@FreeBSD.org>
      * All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
     * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice unmodified, this list of conditions, and the following
     *    disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     *
     * $FreeBSD$
     *
     */
    
    /*
     * uma.h - External definitions for the Universal Memory Allocator
     *
    */
    
    #ifndef _VM_UMA_H_
    #define _VM_UMA_H_
    
    #include <sys/param.h>          /* For NULL */
    #include <sys/malloc.h>         /* For M_* */
    #include <sys/_smr.h>
    
    /* User visible parameters */
    #define UMA_SMALLEST_UNIT       8 /* Smallest item allocated */
    
    /* Types and type defs */
    
    struct uma_zone;
    /* Opaque type used as a handle to the zone */
    typedef struct uma_zone * uma_zone_t;
    
    /*
     * Item constructor
     *
     * Arguments:
     *      item  A pointer to the memory which has been allocated.
     *      arg   The arg field passed to uma_zalloc_arg
     *      size  The size of the allocated item
     *      flags See zalloc flags
     *
     * Returns:
     *      0      on success
     *      errno  on failure
     *
     * Discussion:
     *      The constructor is called just before the memory is returned
     *      to the user. It may block if necessary.
     */
    typedef int (*uma_ctor)(void *mem, int size, void *arg, int flags);
    
    /*
     * Item destructor
     *
     * Arguments:
     *      item  A pointer to the memory which has been allocated.
     *      size  The size of the item being destructed.
     *      arg   Argument passed through uma_zfree_arg
     *
     * Returns:
     *      Nothing
     *
     * Discussion:
     *      The destructor may perform operations that differ from those performed
     *      by the initializer, but it must leave the object in the same state.
     *      This IS type stable storage.  This is called after EVERY zfree call.
     */
    typedef void (*uma_dtor)(void *mem, int size, void *arg);
    
    /*
     * Item initializer
     *
     * Arguments:
     *      item  A pointer to the memory which has been allocated.
     *      size  The size of the item being initialized.
     *      flags See zalloc flags
     *
     * Returns:
    *      0      on success
    *      errno  on failure
    *
    * Discussion:
    *      The initializer is called when the memory is cached in the uma zone.
    *      The initializer and the destructor should leave the object in the same
    *      state.
    */
   typedef int (*uma_init)(void *mem, int size, int flags);
   
   /*
    * Item discard function
    *
    * Arguments:
    *      item  A pointer to memory which has been 'freed' but has not left the
    *            zone's cache.
    *      size  The size of the item being discarded.
    *
    * Returns:
    *      Nothing
    *
    * Discussion:
    *      This routine is called when memory leaves a zone and is returned to the
    *      system for other uses.  It is the counter-part to the init function.
    */
   typedef void (*uma_fini)(void *mem, int size);
   
   /*
    * Import new memory into a cache zone.
    */
   typedef int (*uma_import)(void *arg, void **store, int count, int domain,
       int flags);
   
   /*
    * Free memory from a cache zone.
    */
   typedef void (*uma_release)(void *arg, void **store, int count);
   
   /*
    * What's the difference between initializing and constructing?
    *
    * The item is initialized when it is cached, and this is the state that the
    * object should be in when returned to the allocator. The purpose of this is
    * to remove some code which would otherwise be called on each allocation by
    * utilizing a known, stable state.  This differs from the constructor which
    * will be called on EVERY allocation.
    *
    * For example, in the initializer you may want to initialize embedded locks,
    * NULL list pointers, set up initial states, magic numbers, etc.  This way if
    * the object is held in the allocator and re-used it won't be necessary to
    * re-initialize it.
    *
    * The constructor may be used to lock a data structure, link it on to lists,
    * bump reference counts or total counts of outstanding structures, etc.
    *
    */
   
   /* Function proto types */
   
   /*
    * Create a new uma zone
    *
    * Arguments:
    *      name  The text name of the zone for debugging and stats. This memory
    *              should not be freed until the zone has been deallocated.
    *      size  The size of the object that is being created.
    *      ctor  The constructor that is called when the object is allocated.
    *      dtor  The destructor that is called when the object is freed.
    *      init  An initializer that sets up the initial state of the memory.
    *      fini  A discard function that undoes initialization done by init.
    *              ctor/dtor/init/fini may all be null, see notes above.
    *      align A bitmask that corresponds to the requested alignment
    *              eg 4 would be 0x3
    *      flags A set of parameters that control the behavior of the zone.
    *
    * Returns:
    *      A pointer to a structure which is intended to be opaque to users of
    *      the interface.  The value may be null if the wait flag is not set.
    */
   uma_zone_t uma_zcreate(const char *name, size_t size, uma_ctor ctor,
                       uma_dtor dtor, uma_init uminit, uma_fini fini,
                       int align, uint32_t flags);
   
   /*
    * Create a secondary uma zone
    *
    * Arguments:
    *      name  The text name of the zone for debugging and stats. This memory
    *              should not be freed until the zone has been deallocated.
    *      ctor  The constructor that is called when the object is allocated.
    *      dtor  The destructor that is called when the object is freed.
    *      zinit  An initializer that sets up the initial state of the memory
    *              as the object passes from the Keg's slab to the Zone's cache.
    *      zfini  A discard function that undoes initialization done by init
    *              as the object passes from the Zone's cache to the Keg's slab.
    *
    *              ctor/dtor/zinit/zfini may all be null, see notes above.
    *              Note that the zinit and zfini specified here are NOT
    *              exactly the same as the init/fini specified to uma_zcreate()
    *              when creating a primary zone.  These zinit/zfini are called
    *              on the TRANSITION from keg to zone (and vice-versa). Once
    *              these are set, the primary zone may alter its init/fini
    *              (which are called when the object passes from VM to keg)
    *              using uma_zone_set_init/fini()) as well as its own
    *              zinit/zfini (unset by default for primary zone) with
    *              uma_zone_set_zinit/zfini() (note subtle 'z' prefix).
    *
    *      primary A reference to this zone's Primary Zone which contains the
    *              backing Keg for the Secondary Zone being added.
    *
    * Returns:
    *      A pointer to a structure which is intended to be opaque to users of
    *      the interface.  The value may be null if the wait flag is not set.
    */
   uma_zone_t uma_zsecond_create(const char *name, uma_ctor ctor, uma_dtor dtor,
       uma_init zinit, uma_fini zfini, uma_zone_t primary);
   
   /*
    * Create cache-only zones.
    *
    * This allows uma's per-cpu cache facilities to handle arbitrary
    * pointers.  Consumers must specify the import and release functions to
    * fill and destroy caches.  UMA does not allocate any memory for these
    * zones.  The 'arg' parameter is passed to import/release and is caller
    * specific.
    */
   uma_zone_t uma_zcache_create(const char *name, int size, uma_ctor ctor,
       uma_dtor dtor, uma_init zinit, uma_fini zfini, uma_import zimport,
       uma_release zrelease, void *arg, int flags);
   
   /*
    * Definitions for uma_zcreate flags
    *
    * These flags share space with UMA_ZFLAGs in uma_int.h.  Be careful not to
    * overlap when adding new features.
    */
   #define UMA_ZONE_UNMANAGED      0x0001  /*
                                            * Don't regulate the cache size, even
                                            * under memory pressure.
                                            */
   #define UMA_ZONE_ZINIT          0x0002  /* Initialize with zeros */
   #define UMA_ZONE_CONTIG         0x0004  /*
                                            * Physical memory underlying an object
                                            * must be contiguous.
                                            */
   #define UMA_ZONE_NOTOUCH        0x0008  /* UMA may not access the memory */
   #define UMA_ZONE_MALLOC         0x0010  /* For use by malloc(9) only! */
   #define UMA_ZONE_NOFREE         0x0020  /* Do not free slabs of this type! */
   #define UMA_ZONE_MTXCLASS       0x0040  /* Create a new lock class */
   #define UMA_ZONE_VM             0x0080  /*
                                            * Used for internal vm datastructures
                                            * only.
                                            */
   #define UMA_ZONE_NOTPAGE        0x0100  /* allocf memory not vm pages */
   #define UMA_ZONE_SECONDARY      0x0200  /* Zone is a Secondary Zone */
   #define UMA_ZONE_NOBUCKET       0x0400  /* Do not use buckets. */
   #define UMA_ZONE_MAXBUCKET      0x0800  /* Use largest buckets. */
   #define UMA_ZONE_CACHESPREAD    0x2000  /*
                                            * Spread memory start locations across
                                            * all possible cache lines.  May
                                            * require many virtually contiguous
                                            * backend pages and can fail early.
                                            */
   #define UMA_ZONE_NODUMP         0x4000  /*
                                            * Zone's pages will not be included in
                                            * mini-dumps.
                                            */
   #define UMA_ZONE_PCPU           0x8000  /*
                                            * Allocates mp_maxid + 1 slabs of
                                            * PAGE_SIZE
                                            */
   #define UMA_ZONE_FIRSTTOUCH     0x10000 /* First touch NUMA policy */
   #define UMA_ZONE_ROUNDROBIN     0x20000 /* Round-robin NUMA policy. */
   #define UMA_ZONE_SMR            0x40000 /*
                                            * Safe memory reclamation defers
                                            * frees until all read sections
                                            * have exited.  This flag creates
                                            * a unique SMR context for this
                                            * zone.  To share contexts see
                                            * uma_zone_set_smr() below.
                                            *
                                            * See sys/smr.h for more details.
                                            */
   #define UMA_ZONE_NOKASAN        0x80000 /*
                                            * Disable KASAN verification.  This is
                                            * implied by NOFREE.  Cache zones are
                                            * not verified by default.
                                            */
   /* In use by UMA_ZFLAGs:        0xffe00000 */
   
   /*
    * These flags are shared between the keg and zone.  Some are determined
    * based on physical parameters of the request and may not be provided by
    * the consumer.
    */
   #define UMA_ZONE_INHERIT                                                \
       (UMA_ZONE_NOTOUCH | UMA_ZONE_MALLOC | UMA_ZONE_NOFREE |             \
        UMA_ZONE_VM | UMA_ZONE_NOTPAGE | UMA_ZONE_PCPU |                   \
        UMA_ZONE_FIRSTTOUCH | UMA_ZONE_ROUNDROBIN | UMA_ZONE_NOKASAN)
   
   /* Definitions for align */
   #define UMA_ALIGN_PTR   (sizeof(void *) - 1)    /* Alignment fit for ptr */
   #define UMA_ALIGN_LONG  (sizeof(long) - 1)      /* "" long */
   #define UMA_ALIGN_INT   (sizeof(int) - 1)       /* "" int */
   #define UMA_ALIGN_SHORT (sizeof(short) - 1)     /* "" short */
   #define UMA_ALIGN_CHAR  (sizeof(char) - 1)      /* "" char */
   #define UMA_ALIGN_CACHE (0 - 1)                 /* Cache line size align */
   #define UMA_ALIGNOF(type) (_Alignof(type) - 1)  /* Alignment fit for 'type' */
   
   #define UMA_ANYDOMAIN   -1      /* Special value for domain search. */
   
   /*
    * Destroys an empty uma zone.  If the zone is not empty uma complains loudly.
    *
    * Arguments:
    *      zone  The zone we want to destroy.
    *
    */
   void uma_zdestroy(uma_zone_t zone);
   
   /*
    * Allocates an item out of a zone
    *
    * Arguments:
    *      zone  The zone we are allocating from
    *      arg   This data is passed to the ctor function
    *      flags See sys/malloc.h for available flags.
    *
    * Returns:
    *      A non-null pointer to an initialized element from the zone is
    *      guaranteed if the wait flag is M_WAITOK.  Otherwise a null pointer
    *      may be returned if the zone is empty or the ctor failed.
    */
   
   void *uma_zalloc_arg(uma_zone_t zone, void *arg, int flags);
   
   /* Allocate per-cpu data.  Access the correct data with zpcpu_get(). */
   void *uma_zalloc_pcpu_arg(uma_zone_t zone, void *arg, int flags);
   
   /* Use with SMR zones. */
   void *uma_zalloc_smr(uma_zone_t zone, int flags);
   
   /*
    * Allocate an item from a specific NUMA domain.  This uses a slow path in
    * the allocator but is guaranteed to allocate memory from the requested
    * domain if M_WAITOK is set.
    *
    * Arguments:
    *      zone  The zone we are allocating from
    *      arg   This data is passed to the ctor function
    *      domain The domain to allocate from.
    *      flags See sys/malloc.h for available flags.
    */
   void *uma_zalloc_domain(uma_zone_t zone, void *arg, int domain, int flags);
   
   /*
    * Allocates an item out of a zone without supplying an argument
    *
    * This is just a wrapper for uma_zalloc_arg for convenience.
    *
    */
   static __inline void *uma_zalloc(uma_zone_t zone, int flags);
   static __inline void *uma_zalloc_pcpu(uma_zone_t zone, int flags);
   
   static __inline void *
   uma_zalloc(uma_zone_t zone, int flags)
   {
           return uma_zalloc_arg(zone, NULL, flags);
   }
   
   static __inline void *
   uma_zalloc_pcpu(uma_zone_t zone, int flags)
   {
           return uma_zalloc_pcpu_arg(zone, NULL, flags);
   }
   
   /*
    * Frees an item back into the specified zone.
    *
    * Arguments:
    *      zone  The zone the item was originally allocated out of.
    *      item  The memory to be freed.
    *      arg   Argument passed to the destructor
    *
    * Returns:
    *      Nothing.
    */
   
   void uma_zfree_arg(uma_zone_t zone, void *item, void *arg);
   
   /* Use with PCPU zones. */
   void uma_zfree_pcpu_arg(uma_zone_t zone, void *item, void *arg);
   
   /* Use with SMR zones. */
   void uma_zfree_smr(uma_zone_t zone, void *item);
   
   /*
    * Frees an item back to a zone without supplying an argument
    *
    * This is just a wrapper for uma_zfree_arg for convenience.
    *
    */
   static __inline void uma_zfree(uma_zone_t zone, void *item);
   static __inline void uma_zfree_pcpu(uma_zone_t zone, void *item);
   
   static __inline void
   uma_zfree(uma_zone_t zone, void *item)
   {
           uma_zfree_arg(zone, item, NULL);
   }
   
   static __inline void
   uma_zfree_pcpu(uma_zone_t zone, void *item)
   {
           uma_zfree_pcpu_arg(zone, item, NULL);
   }
   
   /*
    * Wait until the specified zone can allocate an item.
    */
   void uma_zwait(uma_zone_t zone);
   
   /*
    * Backend page supplier routines
    *
    * Arguments:
    *      zone  The zone that is requesting pages.
    *      size  The number of bytes being requested.
    *      pflag Flags for these memory pages, see below.
    *      domain The NUMA domain that we prefer for this allocation.
    *      wait  Indicates our willingness to block.
    *
    * Returns:
    *      A pointer to the allocated memory or NULL on failure.
    */
   
   typedef void *(*uma_alloc)(uma_zone_t zone, vm_size_t size, int domain,
       uint8_t *pflag, int wait);
   
   /*
    * Backend page free routines
    *
    * Arguments:
    *      item  A pointer to the previously allocated pages.
    *      size  The original size of the allocation.
    *      pflag The flags for the slab.  See UMA_SLAB_* below.
    *
    * Returns:
    *      None
    */
   typedef void (*uma_free)(void *item, vm_size_t size, uint8_t pflag);
   
   /*
    * Reclaims unused memory.  If no NUMA domain is specified, memory from all
    * domains is reclaimed.
    *
    * Arguments:
    *      req    Reclamation request type.
    *      domain The target NUMA domain.
    * Returns:
    *      None
    */
   #define UMA_RECLAIM_DRAIN       1       /* release bucket cache */
   #define UMA_RECLAIM_DRAIN_CPU   2       /* release bucket and per-CPU caches */
   #define UMA_RECLAIM_TRIM        3       /* trim bucket cache to WSS */
   void uma_reclaim(int req);
   void uma_reclaim_domain(int req, int domain);
   void uma_zone_reclaim(uma_zone_t, int req);
   void uma_zone_reclaim_domain(uma_zone_t, int req, int domain);
   
   /*
    * Sets the alignment mask to be used for all zones requesting cache
    * alignment.  Should be called by MD boot code prior to starting VM/UMA.
    *
    * Arguments:
    *      align The alignment mask
    *
    * Returns:
    *      Nothing
    */
   void uma_set_align(int align);
   
   /*
    * Set a reserved number of items to hold for M_USE_RESERVE allocations.  All
    * other requests must allocate new backing pages.
    */
   void uma_zone_reserve(uma_zone_t zone, int nitems);
   
   /*
    * Reserves the maximum KVA space required by the zone and configures the zone
    * to use a backend that allocates physical memory and maps it using the
    * reserved KVA. 
    *
    * Arguments:
    *      zone  The zone to update.
    *      nitems  The upper limit on the number of items that can be allocated.
    *
    * Returns:
    *      0  if KVA space can not be allocated
    *      1  if successful
    *
    * Discussion:
    *      When the machine supports a direct map and the zone's items are smaller
    *      than a page, the zone will use the direct map instead of allocating KVA
    *      space.
    */
   int uma_zone_reserve_kva(uma_zone_t zone, int nitems);
   
   /*
    * Sets an upper limit on the number of items allocated from a zone
    *
    * Arguments:
    *      zone  The zone to limit
    *      nitems  The requested upper limit on the number of items allowed
    *
    * Returns:
    *      int  The effective value of nitems
    */
   int uma_zone_set_max(uma_zone_t zone, int nitems);
   
   /*
    * Sets an upper limit on the number of items allowed in zone's caches
    *
    * Arguments:
    *      zone  The zone to limit
    *      nitems  The requested upper limit on the number of items allowed
    */
   void uma_zone_set_maxcache(uma_zone_t zone, int nitems);
   
   /*
    * Obtains the effective limit on the number of items in a zone
    *
    * Arguments:
    *      zone  The zone to obtain the effective limit from
    *
    * Return:
    *      0  No limit
    *      int  The effective limit of the zone
    */
   int uma_zone_get_max(uma_zone_t zone);
   
   /*
    * Sets a warning to be printed when limit is reached
    *
    * Arguments:
    *      zone  The zone we will warn about
    *      warning  Warning content
    *
    * Returns:
    *      Nothing
    */
   void uma_zone_set_warning(uma_zone_t zone, const char *warning);
   
   /*
    * Sets a function to run when limit is reached
    *
    * Arguments:
    *      zone  The zone to which this applies
    *      fx  The function ro run
    *
    * Returns:
    *      Nothing
    */
   typedef void (*uma_maxaction_t)(uma_zone_t, int);
   void uma_zone_set_maxaction(uma_zone_t zone, uma_maxaction_t);
   
   /*
    * Obtains the approximate current number of items allocated from a zone
    *
    * Arguments:
    *      zone  The zone to obtain the current allocation count from
    *
    * Return:
    *      int  The approximate current number of items allocated from the zone
    */
   int uma_zone_get_cur(uma_zone_t zone);
   
   /*
    * The following two routines (uma_zone_set_init/fini)
    * are used to set the backend init/fini pair which acts on an
    * object as it becomes allocated and is placed in a slab within
    * the specified zone's backing keg.  These should probably not
    * be changed once allocations have already begun, but only be set
    * immediately upon zone creation.
    */
   void uma_zone_set_init(uma_zone_t zone, uma_init uminit);
   void uma_zone_set_fini(uma_zone_t zone, uma_fini fini);
   
   /*
    * The following two routines (uma_zone_set_zinit/zfini) are
    * used to set the zinit/zfini pair which acts on an object as
    * it passes from the backing Keg's slab cache to the
    * specified Zone's bucket cache.  These should probably not
    * be changed once allocations have already begun, but only be set
    * immediately upon zone creation.
    */
   void uma_zone_set_zinit(uma_zone_t zone, uma_init zinit);
   void uma_zone_set_zfini(uma_zone_t zone, uma_fini zfini);
   
   /*
    * Replaces the standard backend allocator for this zone.
    *
    * Arguments:
    *      zone   The zone whose backend allocator is being changed.
    *      allocf A pointer to the allocation function
    *
    * Returns:
    *      Nothing
    *
    * Discussion:
    *      This could be used to implement pageable allocation, or perhaps
    *      even DMA allocators if used in conjunction with the OFFPAGE
    *      zone flag.
    */
   
   void uma_zone_set_allocf(uma_zone_t zone, uma_alloc allocf);
   
   /*
    * Used for freeing memory provided by the allocf above
    *
    * Arguments:
    *      zone  The zone that intends to use this free routine.
    *      freef The page freeing routine.
    *
    * Returns:
    *      Nothing
    */
   
   void uma_zone_set_freef(uma_zone_t zone, uma_free freef);
   
   /*
    * Associate a zone with a smr context that is allocated after creation
    * so that multiple zones may share the same context.
    */
   void uma_zone_set_smr(uma_zone_t zone, smr_t smr);
   
   /*
    * Fetch the smr context that was set or made in uma_zcreate().
    */
   smr_t uma_zone_get_smr(uma_zone_t zone);
   
   /*
    * These flags are setable in the allocf and visible in the freef.
    */
   #define UMA_SLAB_BOOT   0x01            /* Slab alloced from boot pages */
   #define UMA_SLAB_KERNEL 0x04            /* Slab alloced from kmem */
   #define UMA_SLAB_PRIV   0x08            /* Slab alloced from priv allocator */
   /* 0x02, 0x10, 0x40, and 0x80 are available */
   
   /*
    * Used to pre-fill a zone with some number of items
    *
    * Arguments:
    *      zone    The zone to fill
    *      itemcnt The number of items to reserve
    *
    * Returns:
    *      Nothing
    *
    * NOTE: This is blocking and should only be done at startup
    */
   void uma_prealloc(uma_zone_t zone, int itemcnt);
   
   /*
    * Used to determine if a fixed-size zone is exhausted.
    *
    * Arguments:
    *      zone    The zone to check
    *
    * Returns:
    *      Non-zero if zone is exhausted.
    */
   int uma_zone_exhausted(uma_zone_t zone);
   
   /*
    * Returns the bytes of memory consumed by the zone.
    */
   size_t uma_zone_memory(uma_zone_t zone);
   
   /*
    * Common UMA_ZONE_PCPU zones.
    */
   extern uma_zone_t pcpu_zone_4;
   extern uma_zone_t pcpu_zone_8;
   extern uma_zone_t pcpu_zone_16;
   extern uma_zone_t pcpu_zone_32;
   extern uma_zone_t pcpu_zone_64;
   
   /*
    * Exported statistics structures to be used by user space monitoring tools.
    * Statistics stream consists of a uma_stream_header, followed by a series of
    * alternative uma_type_header and uma_type_stat structures.
    */
   #define UMA_STREAM_VERSION      0x00000001
   struct uma_stream_header {
           uint32_t        ush_version;    /* Stream format version. */
           uint32_t        ush_maxcpus;    /* Value of MAXCPU for stream. */
           uint32_t        ush_count;      /* Number of records. */
           uint32_t        _ush_pad;       /* Pad/reserved field. */
   };
   
   #define UTH_MAX_NAME    32
   #define UTH_ZONE_SECONDARY      0x00000001
   struct uma_type_header {
           /*
            * Static per-zone data, some extracted from the supporting keg.
            */
           char            uth_name[UTH_MAX_NAME];
           uint32_t        uth_align;      /* Keg: alignment. */
           uint32_t        uth_size;       /* Keg: requested size of item. */
           uint32_t        uth_rsize;      /* Keg: real size of item. */
           uint32_t        uth_maxpages;   /* Keg: maximum number of pages. */
           uint32_t        uth_limit;      /* Keg: max items to allocate. */
   
           /*
            * Current dynamic zone/keg-derived statistics.
            */
           uint32_t        uth_pages;      /* Keg: pages allocated. */
           uint32_t        uth_keg_free;   /* Keg: items free. */
           uint32_t        uth_zone_free;  /* Zone: items free. */
           uint32_t        uth_bucketsize; /* Zone: desired bucket size. */
           uint32_t        uth_zone_flags; /* Zone: flags. */
           uint64_t        uth_allocs;     /* Zone: number of allocations. */
           uint64_t        uth_frees;      /* Zone: number of frees. */
           uint64_t        uth_fails;      /* Zone: number of alloc failures. */
           uint64_t        uth_sleeps;     /* Zone: number of alloc sleeps. */
           uint64_t        uth_xdomain;    /* Zone: Number of cross domain frees. */
           uint64_t        _uth_reserved1[1];      /* Reserved. */
   };
   
   struct uma_percpu_stat {
           uint64_t        ups_allocs;     /* Cache: number of allocations. */
           uint64_t        ups_frees;      /* Cache: number of frees. */
           uint64_t        ups_cache_free; /* Cache: free items in cache. */
           uint64_t        _ups_reserved[5];       /* Reserved. */
   };
   
   void uma_reclaim_wakeup(void);
   void uma_reclaim_worker(void *);
   
   unsigned long uma_limit(void);
   
   /* Return the amount of memory managed by UMA. */
   unsigned long uma_size(void);
   
   /* Return the amount of memory remaining.  May be negative. */
   long uma_avail(void);
   
   #endif  /* _VM_UMA_H_ */

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