The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]

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

Version: -  FREEBSD  -  FREEBSD-12-STABLE  -  FREEBSD-12-0  -  FREEBSD-11-STABLE  -  FREEBSD-11-2  -  FREEBSD-11-1  -  FREEBSD-11-0  -  FREEBSD-10-STABLE  -  FREEBSD-10-4  -  FREEBSD-10-3  -  FREEBSD-10-2  -  FREEBSD-10-1  -  FREEBSD-10-0  -  FREEBSD-9-STABLE  -  FREEBSD-9-3  -  FREEBSD-9-2  -  FREEBSD-9-1  -  FREEBSD-9-0  -  FREEBSD-8-STABLE  -  FREEBSD-8-4  -  FREEBSD-8-3  -  FREEBSD-8-2  -  FREEBSD-8-1  -  FREEBSD-8-0  -  FREEBSD-7-STABLE  -  FREEBSD-7-4  -  FREEBSD-7-3  -  FREEBSD-7-2  -  FREEBSD-7-1  -  FREEBSD-7-0  -  FREEBSD-6-STABLE  -  FREEBSD-6-4  -  FREEBSD-6-3  -  FREEBSD-6-2  -  FREEBSD-6-1  -  FREEBSD-6-0  -  FREEBSD-5-STABLE  -  FREEBSD-5-5  -  FREEBSD-5-4  -  FREEBSD-5-3  -  FREEBSD-5-2  -  FREEBSD-5-1  -  FREEBSD-5-0  -  FREEBSD-4-STABLE  -  FREEBSD-3-STABLE  -  FREEBSD22  -  linux-2.6  -  linux-2.4.22  -  MK83  -  MK84  -  PLAN9  -  DFBSD  -  NETBSD  -  NETBSD5  -  NETBSD4  -  NETBSD3  -  NETBSD20  -  OPENBSD  -  xnu-517  -  xnu-792  -  xnu-792.6.70  -  xnu-1228  -  xnu-1456.1.26  -  xnu-1699.24.8  -  xnu-2050.18.24  -  OPENSOLARIS  -  minix-3-1-1 
SearchContext: -  none  -  3  -  10 

    1 /*-
    2  * Copyright (c) 2002-2005, 2009, 2013 Jeffrey Roberson <jeff@FreeBSD.org>
    3  * Copyright (c) 2004, 2005 Bosko Milekic <bmilekic@FreeBSD.org>
    4  * All rights reserved.
    5  *
    6  * Redistribution and use in source and binary forms, with or without
    7  * modification, are permitted provided that the following conditions
    8  * are met:
    9  * 1. Redistributions of source code must retain the above copyright
   10  *    notice unmodified, this list of conditions, and the following
   11  *    disclaimer.
   12  * 2. Redistributions in binary form must reproduce the above copyright
   13  *    notice, this list of conditions and the following disclaimer in the
   14  *    documentation and/or other materials provided with the distribution.
   15  *
   16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
   17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
   19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
   20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   21  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   23  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
   25  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   26  *
   27  * $FreeBSD: releng/11.2/sys/vm/uma_int.h 324085 2017-09-28 15:23:38Z markj $
   28  *
   29  */
   30 
   31 #include <sys/_bitset.h>
   32 #include <sys/_task.h>
   33 
   34 /* 
   35  * This file includes definitions, structures, prototypes, and inlines that
   36  * should not be used outside of the actual implementation of UMA.
   37  */
   38 
   39 /* 
   40  * Here's a quick description of the relationship between the objects:
   41  *
   42  * Kegs contain lists of slabs which are stored in either the full bin, empty
   43  * bin, or partially allocated bin, to reduce fragmentation.  They also contain
   44  * the user supplied value for size, which is adjusted for alignment purposes
   45  * and rsize is the result of that.  The Keg also stores information for
   46  * managing a hash of page addresses that maps pages to uma_slab_t structures
   47  * for pages that don't have embedded uma_slab_t's.
   48  *  
   49  * The uma_slab_t may be embedded in a UMA_SLAB_SIZE chunk of memory or it may
   50  * be allocated off the page from a special slab zone.  The free list within a
   51  * slab is managed with a bitmask.  For item sizes that would yield more than
   52  * 10% memory waste we potentially allocate a separate uma_slab_t if this will
   53  * improve the number of items per slab that will fit.  
   54  *
   55  * The only really gross cases, with regards to memory waste, are for those
   56  * items that are just over half the page size.   You can get nearly 50% waste,
   57  * so you fall back to the memory footprint of the power of two allocator. I
   58  * have looked at memory allocation sizes on many of the machines available to
   59  * me, and there does not seem to be an abundance of allocations at this range
   60  * so at this time it may not make sense to optimize for it.  This can, of 
   61  * course, be solved with dynamic slab sizes.
   62  *
   63  * Kegs may serve multiple Zones but by far most of the time they only serve
   64  * one.  When a Zone is created, a Keg is allocated and setup for it.  While
   65  * the backing Keg stores slabs, the Zone caches Buckets of items allocated
   66  * from the slabs.  Each Zone is equipped with an init/fini and ctor/dtor
   67  * pair, as well as with its own set of small per-CPU caches, layered above
   68  * the Zone's general Bucket cache.
   69  *
   70  * The PCPU caches are protected by critical sections, and may be accessed
   71  * safely only from their associated CPU, while the Zones backed by the same
   72  * Keg all share a common Keg lock (to coalesce contention on the backing
   73  * slabs).  The backing Keg typically only serves one Zone but in the case of
   74  * multiple Zones, one of the Zones is considered the Master Zone and all
   75  * Zone-related stats from the Keg are done in the Master Zone.  For an
   76  * example of a Multi-Zone setup, refer to the Mbuf allocation code.
   77  */
   78 
   79 /*
   80  *      This is the representation for normal (Non OFFPAGE slab)
   81  *
   82  *      i == item
   83  *      s == slab pointer
   84  *
   85  *      <----------------  Page (UMA_SLAB_SIZE) ------------------>
   86  *      ___________________________________________________________
   87  *     | _  _  _  _  _  _  _  _  _  _  _  _  _  _  _   ___________ |
   88  *     ||i||i||i||i||i||i||i||i||i||i||i||i||i||i||i| |slab header||
   89  *     ||_||_||_||_||_||_||_||_||_||_||_||_||_||_||_| |___________|| 
   90  *     |___________________________________________________________|
   91  *
   92  *
   93  *      This is an OFFPAGE slab. These can be larger than UMA_SLAB_SIZE.
   94  *
   95  *      ___________________________________________________________
   96  *     | _  _  _  _  _  _  _  _  _  _  _  _  _  _  _  _  _  _  _   |
   97  *     ||i||i||i||i||i||i||i||i||i||i||i||i||i||i||i||i||i||i||i|  |
   98  *     ||_||_||_||_||_||_||_||_||_||_||_||_||_||_||_||_||_||_||_|  |
   99  *     |___________________________________________________________|
  100  *       ___________    ^
  101  *      |slab header|   |
  102  *      |___________|---*
  103  *
  104  */
  105 
  106 #ifndef VM_UMA_INT_H
  107 #define VM_UMA_INT_H
  108 
  109 #define UMA_SLAB_SIZE   PAGE_SIZE       /* How big are our slabs? */
  110 #define UMA_SLAB_MASK   (PAGE_SIZE - 1) /* Mask to get back to the page */
  111 #define UMA_SLAB_SHIFT  PAGE_SHIFT      /* Number of bits PAGE_MASK */
  112 
  113 #define UMA_BOOT_PAGES          64      /* Pages allocated for startup */
  114 #define UMA_BOOT_PAGES_ZONES    32      /* Multiplier for pages to reserve */
  115                                         /* if uma_zone > PAGE_SIZE */
  116 
  117 /* Max waste percentage before going to off page slab management */
  118 #define UMA_MAX_WASTE   10
  119 
  120 /*
  121  * I doubt there will be many cases where this is exceeded. This is the initial
  122  * size of the hash table for uma_slabs that are managed off page. This hash
  123  * does expand by powers of two.  Currently it doesn't get smaller.
  124  */
  125 #define UMA_HASH_SIZE_INIT      32              
  126 
  127 /* 
  128  * I should investigate other hashing algorithms.  This should yield a low
  129  * number of collisions if the pages are relatively contiguous.
  130  */
  131 
  132 #define UMA_HASH(h, s) ((((uintptr_t)s) >> UMA_SLAB_SHIFT) & (h)->uh_hashmask)
  133 
  134 #define UMA_HASH_INSERT(h, s, mem)                                      \
  135                 SLIST_INSERT_HEAD(&(h)->uh_slab_hash[UMA_HASH((h),      \
  136                     (mem))], (s), us_hlink)
  137 #define UMA_HASH_REMOVE(h, s, mem)                                      \
  138                 SLIST_REMOVE(&(h)->uh_slab_hash[UMA_HASH((h),           \
  139                     (mem))], (s), uma_slab, us_hlink)
  140 
  141 /* Hash table for freed address -> slab translation */
  142 
  143 SLIST_HEAD(slabhead, uma_slab);
  144 
  145 struct uma_hash {
  146         struct slabhead *uh_slab_hash;  /* Hash table for slabs */
  147         int             uh_hashsize;    /* Current size of the hash table */
  148         int             uh_hashmask;    /* Mask used during hashing */
  149 };
  150 
  151 /*
  152  * align field or structure to cache line
  153  */
  154 #if defined(__amd64__)
  155 #define UMA_ALIGN       __aligned(CACHE_LINE_SIZE)
  156 #else
  157 #define UMA_ALIGN
  158 #endif
  159 
  160 /*
  161  * Structures for per cpu queues.
  162  */
  163 
  164 struct uma_bucket {
  165         LIST_ENTRY(uma_bucket)  ub_link;        /* Link into the zone */
  166         int16_t ub_cnt;                         /* Count of free items. */
  167         int16_t ub_entries;                     /* Max items. */
  168         void    *ub_bucket[];                   /* actual allocation storage */
  169 };
  170 
  171 typedef struct uma_bucket * uma_bucket_t;
  172 
  173 struct uma_cache {
  174         uma_bucket_t    uc_freebucket;  /* Bucket we're freeing to */
  175         uma_bucket_t    uc_allocbucket; /* Bucket to allocate from */
  176         uint64_t        uc_allocs;      /* Count of allocations */
  177         uint64_t        uc_frees;       /* Count of frees */
  178 } UMA_ALIGN;
  179 
  180 typedef struct uma_cache * uma_cache_t;
  181 
  182 /*
  183  * Keg management structure
  184  *
  185  * TODO: Optimize for cache line size
  186  *
  187  */
  188 struct uma_keg {
  189         struct mtx_padalign     uk_lock;        /* Lock for the keg */
  190         struct uma_hash uk_hash;
  191 
  192         LIST_HEAD(,uma_zone)    uk_zones;       /* Keg's zones */
  193         LIST_HEAD(,uma_slab)    uk_part_slab;   /* partially allocated slabs */
  194         LIST_HEAD(,uma_slab)    uk_free_slab;   /* empty slab list */
  195         LIST_HEAD(,uma_slab)    uk_full_slab;   /* full slabs */
  196 
  197         uint32_t        uk_align;       /* Alignment mask */
  198         uint32_t        uk_pages;       /* Total page count */
  199         uint32_t        uk_free;        /* Count of items free in slabs */
  200         uint32_t        uk_reserve;     /* Number of reserved items. */
  201         uint32_t        uk_size;        /* Requested size of each item */
  202         uint32_t        uk_rsize;       /* Real size of each item */
  203         uint32_t        uk_maxpages;    /* Maximum number of pages to alloc */
  204 
  205         uma_init        uk_init;        /* Keg's init routine */
  206         uma_fini        uk_fini;        /* Keg's fini routine */
  207         uma_alloc       uk_allocf;      /* Allocation function */
  208         uma_free        uk_freef;       /* Free routine */
  209 
  210         u_long          uk_offset;      /* Next free offset from base KVA */
  211         vm_offset_t     uk_kva;         /* Zone base KVA */
  212         uma_zone_t      uk_slabzone;    /* Slab zone backing us, if OFFPAGE */
  213 
  214         uint32_t        uk_pgoff;       /* Offset to uma_slab struct */
  215         uint16_t        uk_ppera;       /* pages per allocation from backend */
  216         uint16_t        uk_ipers;       /* Items per slab */
  217         uint32_t        uk_flags;       /* Internal flags */
  218 
  219         /* Least used fields go to the last cache line. */
  220         const char      *uk_name;               /* Name of creating zone. */
  221         LIST_ENTRY(uma_keg)     uk_link;        /* List of all kegs */
  222 };
  223 typedef struct uma_keg  * uma_keg_t;
  224 
  225 /*
  226  * Free bits per-slab.
  227  */
  228 #define SLAB_SETSIZE    (PAGE_SIZE / UMA_SMALLEST_UNIT)
  229 BITSET_DEFINE(slabbits, SLAB_SETSIZE);
  230 
  231 /*
  232  * The slab structure manages a single contiguous allocation from backing
  233  * store and subdivides it into individually allocatable items.
  234  */
  235 struct uma_slab {
  236         uma_keg_t       us_keg;                 /* Keg we live in */
  237         union {
  238                 LIST_ENTRY(uma_slab)    _us_link;       /* slabs in zone */
  239                 unsigned long   _us_size;       /* Size of allocation */
  240         } us_type;
  241         SLIST_ENTRY(uma_slab)   us_hlink;       /* Link for hash table */
  242         uint8_t         *us_data;               /* First item */
  243         struct slabbits us_free;                /* Free bitmask. */
  244 #ifdef INVARIANTS
  245         struct slabbits us_debugfree;           /* Debug bitmask. */
  246 #endif
  247         uint16_t        us_freecount;           /* How many are free? */
  248         uint8_t         us_flags;               /* Page flags see uma.h */
  249         uint8_t         us_pad;                 /* Pad to 32bits, unused. */
  250 };
  251 
  252 #define us_link us_type._us_link
  253 #define us_size us_type._us_size
  254 
  255 typedef struct uma_slab * uma_slab_t;
  256 typedef uma_slab_t (*uma_slaballoc)(uma_zone_t, uma_keg_t, int);
  257 
  258 struct uma_klink {
  259         LIST_ENTRY(uma_klink)   kl_link;
  260         uma_keg_t               kl_keg;
  261 };
  262 typedef struct uma_klink *uma_klink_t;
  263 
  264 /*
  265  * Zone management structure 
  266  *
  267  * TODO: Optimize for cache line size
  268  *
  269  */
  270 struct uma_zone {
  271         struct mtx_padalign     uz_lock;        /* Lock for the zone */
  272         struct mtx_padalign     *uz_lockptr;
  273         const char              *uz_name;       /* Text name of the zone */
  274 
  275         LIST_ENTRY(uma_zone)    uz_link;        /* List of all zones in keg */
  276         LIST_HEAD(,uma_bucket)  uz_buckets;     /* full buckets */
  277 
  278         LIST_HEAD(,uma_klink)   uz_kegs;        /* List of kegs. */
  279         struct uma_klink        uz_klink;       /* klink for first keg. */
  280 
  281         uma_slaballoc   uz_slab;        /* Allocate a slab from the backend. */
  282         uma_ctor        uz_ctor;        /* Constructor for each allocation */
  283         uma_dtor        uz_dtor;        /* Destructor */
  284         uma_init        uz_init;        /* Initializer for each item */
  285         uma_fini        uz_fini;        /* Finalizer for each item. */
  286         uma_import      uz_import;      /* Import new memory to cache. */
  287         uma_release     uz_release;     /* Release memory from cache. */
  288         void            *uz_arg;        /* Import/release argument. */
  289 
  290         uint32_t        uz_flags;       /* Flags inherited from kegs */
  291         uint32_t        uz_size;        /* Size inherited from kegs */
  292 
  293         volatile u_long uz_allocs UMA_ALIGN; /* Total number of allocations */
  294         volatile u_long uz_fails;       /* Total number of alloc failures */
  295         volatile u_long uz_frees;       /* Total number of frees */
  296         uint64_t        uz_sleeps;      /* Total number of alloc sleeps */
  297         uint16_t        uz_count;       /* Amount of items in full bucket */
  298         uint16_t        uz_count_min;   /* Minimal amount of items there */
  299 
  300         /* The next two fields are used to print a rate-limited warnings. */
  301         const char      *uz_warning;    /* Warning to print on failure */
  302         struct timeval  uz_ratecheck;   /* Warnings rate-limiting */
  303 
  304         struct task     uz_maxaction;   /* Task to run when at limit */
  305 
  306         /*
  307          * This HAS to be the last item because we adjust the zone size
  308          * based on NCPU and then allocate the space for the zones.
  309          */
  310         struct uma_cache        uz_cpu[1]; /* Per cpu caches */
  311 };
  312 
  313 /*
  314  * These flags must not overlap with the UMA_ZONE flags specified in uma.h.
  315  */
  316 #define UMA_ZFLAG_MULTI         0x04000000      /* Multiple kegs in the zone. */
  317 #define UMA_ZFLAG_DRAINING      0x08000000      /* Running zone_drain. */
  318 #define UMA_ZFLAG_BUCKET        0x10000000      /* Bucket zone. */
  319 #define UMA_ZFLAG_INTERNAL      0x20000000      /* No offpage no PCPU. */
  320 #define UMA_ZFLAG_FULL          0x40000000      /* Reached uz_maxpages */
  321 #define UMA_ZFLAG_CACHEONLY     0x80000000      /* Don't ask VM for buckets. */
  322 
  323 #define UMA_ZFLAG_INHERIT                                               \
  324     (UMA_ZFLAG_INTERNAL | UMA_ZFLAG_CACHEONLY | UMA_ZFLAG_BUCKET)
  325 
  326 static inline uma_keg_t
  327 zone_first_keg(uma_zone_t zone)
  328 {
  329         uma_klink_t klink;
  330 
  331         klink = LIST_FIRST(&zone->uz_kegs);
  332         return (klink != NULL) ? klink->kl_keg : NULL;
  333 }
  334 
  335 #undef UMA_ALIGN
  336 
  337 #ifdef _KERNEL
  338 /* Internal prototypes */
  339 static __inline uma_slab_t hash_sfind(struct uma_hash *hash, uint8_t *data);
  340 void *uma_large_malloc(vm_size_t size, int wait);
  341 void uma_large_free(uma_slab_t slab);
  342 
  343 /* Lock Macros */
  344 
  345 #define KEG_LOCK_INIT(k, lc)                                    \
  346         do {                                                    \
  347                 if ((lc))                                       \
  348                         mtx_init(&(k)->uk_lock, (k)->uk_name,   \
  349                             (k)->uk_name, MTX_DEF | MTX_DUPOK); \
  350                 else                                            \
  351                         mtx_init(&(k)->uk_lock, (k)->uk_name,   \
  352                             "UMA zone", MTX_DEF | MTX_DUPOK);   \
  353         } while (0)
  354 
  355 #define KEG_LOCK_FINI(k)        mtx_destroy(&(k)->uk_lock)
  356 #define KEG_LOCK(k)     mtx_lock(&(k)->uk_lock)
  357 #define KEG_UNLOCK(k)   mtx_unlock(&(k)->uk_lock)
  358 
  359 #define ZONE_LOCK_INIT(z, lc)                                   \
  360         do {                                                    \
  361                 if ((lc))                                       \
  362                         mtx_init(&(z)->uz_lock, (z)->uz_name,   \
  363                             (z)->uz_name, MTX_DEF | MTX_DUPOK); \
  364                 else                                            \
  365                         mtx_init(&(z)->uz_lock, (z)->uz_name,   \
  366                             "UMA zone", MTX_DEF | MTX_DUPOK);   \
  367         } while (0)
  368             
  369 #define ZONE_LOCK(z)    mtx_lock((z)->uz_lockptr)
  370 #define ZONE_TRYLOCK(z) mtx_trylock((z)->uz_lockptr)
  371 #define ZONE_UNLOCK(z)  mtx_unlock((z)->uz_lockptr)
  372 #define ZONE_LOCK_FINI(z)       mtx_destroy(&(z)->uz_lock)
  373 
  374 /*
  375  * Find a slab within a hash table.  This is used for OFFPAGE zones to lookup
  376  * the slab structure.
  377  *
  378  * Arguments:
  379  *      hash  The hash table to search.
  380  *      data  The base page of the item.
  381  *
  382  * Returns:
  383  *      A pointer to a slab if successful, else NULL.
  384  */
  385 static __inline uma_slab_t
  386 hash_sfind(struct uma_hash *hash, uint8_t *data)
  387 {
  388         uma_slab_t slab;
  389         int hval;
  390 
  391         hval = UMA_HASH(hash, data);
  392 
  393         SLIST_FOREACH(slab, &hash->uh_slab_hash[hval], us_hlink) {
  394                 if ((uint8_t *)slab->us_data == data)
  395                         return (slab);
  396         }
  397         return (NULL);
  398 }
  399 
  400 static __inline uma_slab_t
  401 vtoslab(vm_offset_t va)
  402 {
  403         vm_page_t p;
  404 
  405         p = PHYS_TO_VM_PAGE(pmap_kextract(va));
  406         return ((uma_slab_t)p->plinks.s.pv);
  407 }
  408 
  409 static __inline void
  410 vsetslab(vm_offset_t va, uma_slab_t slab)
  411 {
  412         vm_page_t p;
  413 
  414         p = PHYS_TO_VM_PAGE(pmap_kextract(va));
  415         p->plinks.s.pv = slab;
  416 }
  417 
  418 /*
  419  * The following two functions may be defined by architecture specific code
  420  * if they can provide more efficient allocation functions.  This is useful
  421  * for using direct mapped addresses.
  422  */
  423 void *uma_small_alloc(uma_zone_t zone, vm_size_t bytes, uint8_t *pflag,
  424     int wait);
  425 void uma_small_free(void *mem, vm_size_t size, uint8_t flags);
  426 #endif /* _KERNEL */
  427 
  428 #endif /* VM_UMA_INT_H */

Cache object: d6dab995b5242854b10309f535a8f81d


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]


This page is part of the FreeBSD/Linux Linux Kernel Cross-Reference, and was automatically generated using a modified version of the LXR engine.