Subversion Repositories HelenOS-historic

Rev

Rev 1682 | Rev 1757 | Go to most recent revision | Blame | Compare with Previous | Last modification | View Log | Download | RSS feed

  1. /*
  2.  * Copyright (C) 2006 Ondrej Palkovsky
  3.  * All rights reserved.
  4.  *
  5.  * Redistribution and use in source and binary forms, with or without
  6.  * modification, are permitted provided that the following conditions
  7.  * are met:
  8.  *
  9.  * - Redistributions of source code must retain the above copyright
  10.  *   notice, this list of conditions and the following disclaimer.
  11.  * - Redistributions in binary form must reproduce the above copyright
  12.  *   notice, this list of conditions and the following disclaimer in the
  13.  *   documentation and/or other materials provided with the distribution.
  14.  * - The name of the author may not be used to endorse or promote products
  15.  *   derived from this software without specific prior written permission.
  16.  *
  17.  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18.  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19.  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20.  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21.  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22.  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23.  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24.  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25.  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26.  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27.  */
  28.  
  29.  /** @addtogroup genericmm
  30.  * @{
  31.  */
  32.  
  33. /**
  34.  * @file
  35.  * @brief   Slab allocator.
  36.  *
  37.  * The slab allocator is closely modelled after OpenSolaris slab allocator.
  38.  * @see http://www.usenix.org/events/usenix01/full_papers/bonwick/bonwick_html/
  39.  *
  40.  * with the following exceptions:
  41.  * @li empty slabs are deallocated immediately
  42.  *     (in Linux they are kept in linked list, in Solaris ???)
  43.  * @li empty magazines are deallocated when not needed
  44.  *     (in Solaris they are held in linked list in slab cache)
  45.  *
  46.  * Following features are not currently supported but would be easy to do:
  47.  * @li cache coloring
  48.  * @li dynamic magazine growing (different magazine sizes are already
  49.  *     supported, but we would need to adjust allocation strategy)
  50.  *
  51.  * The slab allocator supports per-CPU caches ('magazines') to facilitate
  52.  * good SMP scaling.
  53.  *
  54.  * When a new object is being allocated, it is first checked, if it is
  55.  * available in a CPU-bound magazine. If it is not found there, it is
  56.  * allocated from a CPU-shared slab - if a partially full one is found,
  57.  * it is used, otherwise a new one is allocated.
  58.  *
  59.  * When an object is being deallocated, it is put to a CPU-bound magazine.
  60.  * If there is no such magazine, a new one is allocated (if this fails,
  61.  * the object is deallocated into slab). If the magazine is full, it is
  62.  * put into cpu-shared list of magazines and a new one is allocated.
  63.  *
  64.  * The CPU-bound magazine is actually a pair of magazines in order to avoid
  65.  * thrashing when somebody is allocating/deallocating 1 item at the magazine
  66.  * size boundary. LIFO order is enforced, which should avoid fragmentation
  67.  * as much as possible.
  68.  *  
  69.  * Every cache contains list of full slabs and list of partially full slabs.
  70.  * Empty slabs are immediately freed (thrashing will be avoided because
  71.  * of magazines).
  72.  *
  73.  * The slab information structure is kept inside the data area, if possible.
  74.  * The cache can be marked that it should not use magazines. This is used
  75.  * only for slab related caches to avoid deadlocks and infinite recursion
  76.  * (the slab allocator uses itself for allocating all it's control structures).
  77.  *
  78.  * The slab allocator allocates a lot of space and does not free it. When
  79.  * the frame allocator fails to allocate a frame, it calls slab_reclaim().
  80.  * It tries 'light reclaim' first, then brutal reclaim. The light reclaim
  81.  * releases slabs from cpu-shared magazine-list, until at least 1 slab
  82.  * is deallocated in each cache (this algorithm should probably change).
  83.  * The brutal reclaim removes all cached objects, even from CPU-bound
  84.  * magazines.
  85.  *
  86.  * TODO:@n
  87.  * For better CPU-scaling the magazine allocation strategy should
  88.  * be extended. Currently, if the cache does not have magazine, it asks
  89.  * for non-cpu cached magazine cache to provide one. It might be feasible
  90.  * to add cpu-cached magazine cache (which would allocate it's magazines
  91.  * from non-cpu-cached mag. cache). This would provide a nice per-cpu
  92.  * buffer. The other possibility is to use the per-cache
  93.  * 'empty-magazine-list', which decreases competing for 1 per-system
  94.  * magazine cache.
  95.  *
  96.  * @li it might be good to add granularity of locks even to slab level,
  97.  *     we could then try_spinlock over all partial slabs and thus improve
  98.  *     scalability even on slab level
  99.  */
  100.  
  101. #include <synch/spinlock.h>
  102. #include <mm/slab.h>
  103. #include <adt/list.h>
  104. #include <memstr.h>
  105. #include <align.h>
  106. #include <mm/frame.h>
  107. #include <config.h>
  108. #include <print.h>
  109. #include <arch.h>
  110. #include <panic.h>
  111. #include <debug.h>
  112. #include <bitops.h>
  113.  
  114. SPINLOCK_INITIALIZE(slab_cache_lock);
  115. static LIST_INITIALIZE(slab_cache_list);
  116.  
  117. /** Magazine cache */
  118. static slab_cache_t mag_cache;
  119. /** Cache for cache descriptors */
  120. static slab_cache_t slab_cache_cache;
  121. /** Cache for external slab descriptors
  122.  * This time we want per-cpu cache, so do not make it static
  123.  * - using slab for internal slab structures will not deadlock,
  124.  *   as all slab structures are 'small' - control structures of
  125.  *   their caches do not require further allocation
  126.  */
  127. static slab_cache_t *slab_extern_cache;
  128. /** Caches for malloc */
  129. static slab_cache_t *malloc_caches[SLAB_MAX_MALLOC_W-SLAB_MIN_MALLOC_W+1];
  130. char *malloc_names[] =  {
  131.     "malloc-16","malloc-32","malloc-64","malloc-128",
  132.     "malloc-256","malloc-512","malloc-1K","malloc-2K",
  133.     "malloc-4K","malloc-8K","malloc-16K","malloc-32K",
  134.     "malloc-64K","malloc-128K","malloc-256K"
  135. };
  136.  
  137. /** Slab descriptor */
  138. typedef struct {
  139.     slab_cache_t *cache; /**< Pointer to parent cache */
  140.     link_t link;       /* List of full/partial slabs */
  141.     void *start;       /**< Start address of first available item */
  142.     count_t available; /**< Count of available items in this slab */
  143.     index_t nextavail; /**< The index of next available item */
  144. }slab_t;
  145.  
  146. #ifdef CONFIG_DEBUG
  147. static int _slab_initialized = 0;
  148. #endif
  149.  
  150. /**************************************/
  151. /* Slab allocation functions          */
  152.  
  153. /**
  154.  * Allocate frames for slab space and initialize
  155.  *
  156.  */
  157. static slab_t * slab_space_alloc(slab_cache_t *cache, int flags)
  158. {
  159.     void *data;
  160.     slab_t *slab;
  161.     size_t fsize;
  162.     int i;
  163.     int status;
  164.     pfn_t pfn;
  165.     int zone=0;
  166.    
  167.     pfn = frame_alloc_rc_zone(cache->order, FRAME_KA | flags, &status, &zone);
  168.     data = (void *) PA2KA(PFN2ADDR(pfn));
  169.     if (status != FRAME_OK) {
  170.         return NULL;
  171.     }
  172.     if (! (cache->flags & SLAB_CACHE_SLINSIDE)) {
  173.         slab = slab_alloc(slab_extern_cache, flags);
  174.         if (!slab) {
  175.             frame_free(ADDR2PFN(KA2PA(data)));
  176.             return NULL;
  177.         }
  178.     } else {
  179.         fsize = (PAGE_SIZE << cache->order);
  180.         slab = data + fsize - sizeof(*slab);
  181.     }
  182.    
  183.     /* Fill in slab structures */
  184.     for (i=0; i < (1 << cache->order); i++)
  185.         frame_set_parent(pfn+i, slab, zone);
  186.  
  187.     slab->start = data;
  188.     slab->available = cache->objects;
  189.     slab->nextavail = 0;
  190.     slab->cache = cache;
  191.  
  192.     for (i=0; i<cache->objects;i++)
  193.         *((int *) (slab->start + i*cache->size)) = i+1;
  194.  
  195.     atomic_inc(&cache->allocated_slabs);
  196.     return slab;
  197. }
  198.  
  199. /**
  200.  * Deallocate space associated with slab
  201.  *
  202.  * @return number of freed frames
  203.  */
  204. static count_t slab_space_free(slab_cache_t *cache, slab_t *slab)
  205. {
  206.     frame_free(ADDR2PFN(KA2PA(slab->start)));
  207.     if (! (cache->flags & SLAB_CACHE_SLINSIDE))
  208.         slab_free(slab_extern_cache, slab);
  209.  
  210.     atomic_dec(&cache->allocated_slabs);
  211.    
  212.     return 1 << cache->order;
  213. }
  214.  
  215. /** Map object to slab structure */
  216. static slab_t * obj2slab(void *obj)
  217. {
  218.     return (slab_t *)frame_get_parent(ADDR2PFN(KA2PA(obj)), 0);
  219. }
  220.  
  221. /**************************************/
  222. /* Slab functions */
  223.  
  224.  
  225. /**
  226.  * Return object to slab and call a destructor
  227.  *
  228.  * @param slab If the caller knows directly slab of the object, otherwise NULL
  229.  *
  230.  * @return Number of freed pages
  231.  */
  232. static count_t slab_obj_destroy(slab_cache_t *cache, void *obj,
  233.                 slab_t *slab)
  234. {
  235.     int freed = 0;
  236.  
  237.     if (!slab)
  238.         slab = obj2slab(obj);
  239.  
  240.     ASSERT(slab->cache == cache);
  241.  
  242.     if (cache->destructor)
  243.         freed = cache->destructor(obj);
  244.    
  245.     spinlock_lock(&cache->slablock);
  246.     ASSERT(slab->available < cache->objects);
  247.  
  248.     *((int *)obj) = slab->nextavail;
  249.     slab->nextavail = (obj - slab->start)/cache->size;
  250.     slab->available++;
  251.  
  252.     /* Move it to correct list */
  253.     if (slab->available == cache->objects) {
  254.         /* Free associated memory */
  255.         list_remove(&slab->link);
  256.         spinlock_unlock(&cache->slablock);
  257.  
  258.         return freed + slab_space_free(cache, slab);
  259.  
  260.     } else if (slab->available == 1) {
  261.         /* It was in full, move to partial */
  262.         list_remove(&slab->link);
  263.         list_prepend(&slab->link, &cache->partial_slabs);
  264.     }
  265.     spinlock_unlock(&cache->slablock);
  266.     return freed;
  267. }
  268.  
  269. /**
  270.  * Take new object from slab or create new if needed
  271.  *
  272.  * @return Object address or null
  273.  */
  274. static void * slab_obj_create(slab_cache_t *cache, int flags)
  275. {
  276.     slab_t *slab;
  277.     void *obj;
  278.  
  279.     spinlock_lock(&cache->slablock);
  280.  
  281.     if (list_empty(&cache->partial_slabs)) {
  282.         /* Allow recursion and reclaiming
  283.          * - this should work, as the slab control structures
  284.          *   are small and do not need to allocate with anything
  285.          *   other than frame_alloc when they are allocating,
  286.          *   that's why we should get recursion at most 1-level deep
  287.          */
  288.         spinlock_unlock(&cache->slablock);
  289.         slab = slab_space_alloc(cache, flags);
  290.         if (!slab)
  291.             return NULL;
  292.         spinlock_lock(&cache->slablock);
  293.     } else {
  294.         slab = list_get_instance(cache->partial_slabs.next,
  295.                      slab_t,
  296.                      link);
  297.         list_remove(&slab->link);
  298.     }
  299.     obj = slab->start + slab->nextavail * cache->size;
  300.     slab->nextavail = *((int *)obj);
  301.     slab->available--;
  302.  
  303.     if (! slab->available)
  304.         list_prepend(&slab->link, &cache->full_slabs);
  305.     else
  306.         list_prepend(&slab->link, &cache->partial_slabs);
  307.  
  308.     spinlock_unlock(&cache->slablock);
  309.  
  310.     if (cache->constructor && cache->constructor(obj, flags)) {
  311.         /* Bad, bad, construction failed */
  312.         slab_obj_destroy(cache, obj, slab);
  313.         return NULL;
  314.     }
  315.     return obj;
  316. }
  317.  
  318. /**************************************/
  319. /* CPU-Cache slab functions */
  320.  
  321. /**
  322.  * Finds a full magazine in cache, takes it from list
  323.  * and returns it
  324.  *
  325.  * @param first If true, return first, else last mag
  326.  */
  327. static slab_magazine_t * get_mag_from_cache(slab_cache_t *cache,
  328.                         int first)
  329. {
  330.     slab_magazine_t *mag = NULL;
  331.     link_t *cur;
  332.  
  333.     spinlock_lock(&cache->maglock);
  334.     if (!list_empty(&cache->magazines)) {
  335.         if (first)
  336.             cur = cache->magazines.next;
  337.         else
  338.             cur = cache->magazines.prev;
  339.         mag = list_get_instance(cur, slab_magazine_t, link);
  340.         list_remove(&mag->link);
  341.         atomic_dec(&cache->magazine_counter);
  342.     }
  343.     spinlock_unlock(&cache->maglock);
  344.     return mag;
  345. }
  346.  
  347. /** Prepend magazine to magazine list in cache */
  348. static void put_mag_to_cache(slab_cache_t *cache, slab_magazine_t *mag)
  349. {
  350.     spinlock_lock(&cache->maglock);
  351.  
  352.     list_prepend(&mag->link, &cache->magazines);
  353.     atomic_inc(&cache->magazine_counter);
  354.    
  355.     spinlock_unlock(&cache->maglock);
  356. }
  357.  
  358. /**
  359.  * Free all objects in magazine and free memory associated with magazine
  360.  *
  361.  * @return Number of freed pages
  362.  */
  363. static count_t magazine_destroy(slab_cache_t *cache,
  364.                 slab_magazine_t *mag)
  365. {
  366.     int i;
  367.     count_t frames = 0;
  368.  
  369.     for (i=0;i < mag->busy; i++) {
  370.         frames += slab_obj_destroy(cache, mag->objs[i], NULL);
  371.         atomic_dec(&cache->cached_objs);
  372.     }
  373.    
  374.     slab_free(&mag_cache, mag);
  375.  
  376.     return frames;
  377. }
  378.  
  379. /**
  380.  * Find full magazine, set it as current and return it
  381.  *
  382.  * Assume cpu_magazine lock is held
  383.  */
  384. static slab_magazine_t * get_full_current_mag(slab_cache_t *cache)
  385. {
  386.     slab_magazine_t *cmag, *lastmag, *newmag;
  387.  
  388.     cmag = cache->mag_cache[CPU->id].current;
  389.     lastmag = cache->mag_cache[CPU->id].last;
  390.     if (cmag) { /* First try local CPU magazines */
  391.         if (cmag->busy)
  392.             return cmag;
  393.  
  394.         if (lastmag && lastmag->busy) {
  395.             cache->mag_cache[CPU->id].current = lastmag;
  396.             cache->mag_cache[CPU->id].last = cmag;
  397.             return lastmag;
  398.         }
  399.     }
  400.     /* Local magazines are empty, import one from magazine list */
  401.     newmag = get_mag_from_cache(cache, 1);
  402.     if (!newmag)
  403.         return NULL;
  404.  
  405.     if (lastmag)
  406.         magazine_destroy(cache, lastmag);
  407.  
  408.     cache->mag_cache[CPU->id].last = cmag;
  409.     cache->mag_cache[CPU->id].current = newmag;
  410.     return newmag;
  411. }
  412.  
  413. /**
  414.  * Try to find object in CPU-cache magazines
  415.  *
  416.  * @return Pointer to object or NULL if not available
  417.  */
  418. static void * magazine_obj_get(slab_cache_t *cache)
  419. {
  420.     slab_magazine_t *mag;
  421.     void *obj;
  422.  
  423.     if (!CPU)
  424.         return NULL;
  425.  
  426.     spinlock_lock(&cache->mag_cache[CPU->id].lock);
  427.  
  428.     mag = get_full_current_mag(cache);
  429.     if (!mag) {
  430.         spinlock_unlock(&cache->mag_cache[CPU->id].lock);
  431.         return NULL;
  432.     }
  433.     obj = mag->objs[--mag->busy];
  434.     spinlock_unlock(&cache->mag_cache[CPU->id].lock);
  435.     atomic_dec(&cache->cached_objs);
  436.    
  437.     return obj;
  438. }
  439.  
  440. /**
  441.  * Assure that the current magazine is empty, return pointer to it, or NULL if
  442.  * no empty magazine is available and cannot be allocated
  443.  *
  444.  * Assume mag_cache[CPU->id].lock is held
  445.  *
  446.  * We have 2 magazines bound to processor.
  447.  * First try the current.
  448.  *  If full, try the last.
  449.  *   If full, put to magazines list.
  450.  *   allocate new, exchange last & current
  451.  *
  452.  */
  453. static slab_magazine_t * make_empty_current_mag(slab_cache_t *cache)
  454. {
  455.     slab_magazine_t *cmag,*lastmag,*newmag;
  456.  
  457.     cmag = cache->mag_cache[CPU->id].current;
  458.     lastmag = cache->mag_cache[CPU->id].last;
  459.  
  460.     if (cmag) {
  461.         if (cmag->busy < cmag->size)
  462.             return cmag;
  463.         if (lastmag && lastmag->busy < lastmag->size) {
  464.             cache->mag_cache[CPU->id].last = cmag;
  465.             cache->mag_cache[CPU->id].current = lastmag;
  466.             return lastmag;
  467.         }
  468.     }
  469.     /* current | last are full | nonexistent, allocate new */
  470.     /* We do not want to sleep just because of caching */
  471.     /* Especially we do not want reclaiming to start, as
  472.      * this would deadlock */
  473.     newmag = slab_alloc(&mag_cache, FRAME_ATOMIC | FRAME_NO_RECLAIM);
  474.     if (!newmag)
  475.         return NULL;
  476.     newmag->size = SLAB_MAG_SIZE;
  477.     newmag->busy = 0;
  478.  
  479.     /* Flush last to magazine list */
  480.     if (lastmag)
  481.         put_mag_to_cache(cache, lastmag);
  482.  
  483.     /* Move current as last, save new as current */
  484.     cache->mag_cache[CPU->id].last = cmag; 
  485.     cache->mag_cache[CPU->id].current = newmag;
  486.  
  487.     return newmag;
  488. }
  489.  
  490. /**
  491.  * Put object into CPU-cache magazine
  492.  *
  493.  * @return 0 - success, -1 - could not get memory
  494.  */
  495. static int magazine_obj_put(slab_cache_t *cache, void *obj)
  496. {
  497.     slab_magazine_t *mag;
  498.  
  499.     if (!CPU)
  500.         return -1;
  501.  
  502.     spinlock_lock(&cache->mag_cache[CPU->id].lock);
  503.  
  504.     mag = make_empty_current_mag(cache);
  505.     if (!mag) {
  506.         spinlock_unlock(&cache->mag_cache[CPU->id].lock);
  507.         return -1;
  508.     }
  509.    
  510.     mag->objs[mag->busy++] = obj;
  511.  
  512.     spinlock_unlock(&cache->mag_cache[CPU->id].lock);
  513.     atomic_inc(&cache->cached_objs);
  514.     return 0;
  515. }
  516.  
  517.  
  518. /**************************************/
  519. /* Slab cache functions */
  520.  
  521. /** Return number of objects that fit in certain cache size */
  522. static int comp_objects(slab_cache_t *cache)
  523. {
  524.     if (cache->flags & SLAB_CACHE_SLINSIDE)
  525.         return ((PAGE_SIZE << cache->order) - sizeof(slab_t)) / cache->size;
  526.     else
  527.         return (PAGE_SIZE << cache->order) / cache->size;
  528. }
  529.  
  530. /** Return wasted space in slab */
  531. static int badness(slab_cache_t *cache)
  532. {
  533.     int objects;
  534.     int ssize;
  535.  
  536.     objects = comp_objects(cache);
  537.     ssize = PAGE_SIZE << cache->order;
  538.     if (cache->flags & SLAB_CACHE_SLINSIDE)
  539.         ssize -= sizeof(slab_t);
  540.     return ssize - objects*cache->size;
  541. }
  542.  
  543. /**
  544.  * Initialize mag_cache structure in slab cache
  545.  */
  546. static void make_magcache(slab_cache_t *cache)
  547. {
  548.     int i;
  549.    
  550.     ASSERT(_slab_initialized >= 2);
  551.  
  552.     cache->mag_cache = malloc(sizeof(slab_mag_cache_t)*config.cpu_count,0);
  553.     for (i=0; i < config.cpu_count; i++) {
  554.         memsetb((__address)&cache->mag_cache[i],
  555.             sizeof(cache->mag_cache[i]), 0);
  556.         spinlock_initialize(&cache->mag_cache[i].lock,
  557.                     "slab_maglock_cpu");
  558.     }
  559. }
  560.  
  561. /** Initialize allocated memory as a slab cache */
  562. static void
  563. _slab_cache_create(slab_cache_t *cache,
  564.            char *name,
  565.            size_t size,
  566.            size_t align,
  567.            int (*constructor)(void *obj, int kmflag),
  568.            int (*destructor)(void *obj),
  569.            int flags)
  570. {
  571.     int pages;
  572.     ipl_t ipl;
  573.  
  574.     memsetb((__address)cache, sizeof(*cache), 0);
  575.     cache->name = name;
  576.  
  577.     if (align < sizeof(__native))
  578.         align = sizeof(__native);
  579.     size = ALIGN_UP(size, align);
  580.        
  581.     cache->size = size;
  582.  
  583.     cache->constructor = constructor;
  584.     cache->destructor = destructor;
  585.     cache->flags = flags;
  586.  
  587.     list_initialize(&cache->full_slabs);
  588.     list_initialize(&cache->partial_slabs);
  589.     list_initialize(&cache->magazines);
  590.     spinlock_initialize(&cache->slablock, "slab_lock");
  591.     spinlock_initialize(&cache->maglock, "slab_maglock");
  592.     if (! (cache->flags & SLAB_CACHE_NOMAGAZINE))
  593.         make_magcache(cache);
  594.  
  595.     /* Compute slab sizes, object counts in slabs etc. */
  596.     if (cache->size < SLAB_INSIDE_SIZE)
  597.         cache->flags |= SLAB_CACHE_SLINSIDE;
  598.  
  599.     /* Minimum slab order */
  600.     pages = SIZE2FRAMES(cache->size);
  601.     /* We need the 2^order >= pages */
  602.     if (pages == 1)
  603.         cache->order = 0;
  604.     else
  605.         cache->order = fnzb(pages-1)+1;
  606.  
  607.     while (badness(cache) > SLAB_MAX_BADNESS(cache)) {
  608.         cache->order += 1;
  609.     }
  610.     cache->objects = comp_objects(cache);
  611.     /* If info fits in, put it inside */
  612.     if (badness(cache) > sizeof(slab_t))
  613.         cache->flags |= SLAB_CACHE_SLINSIDE;
  614.  
  615.     /* Add cache to cache list */
  616.     ipl = interrupts_disable();
  617.     spinlock_lock(&slab_cache_lock);
  618.  
  619.     list_append(&cache->link, &slab_cache_list);
  620.  
  621.     spinlock_unlock(&slab_cache_lock);
  622.     interrupts_restore(ipl);
  623. }
  624.  
  625. /** Create slab cache  */
  626. slab_cache_t * slab_cache_create(char *name,
  627.                  size_t size,
  628.                  size_t align,
  629.                  int (*constructor)(void *obj, int kmflag),
  630.                  int (*destructor)(void *obj),
  631.                  int flags)
  632. {
  633.     slab_cache_t *cache;
  634.  
  635.     cache = slab_alloc(&slab_cache_cache, 0);
  636.     _slab_cache_create(cache, name, size, align, constructor, destructor,
  637.                flags);
  638.     return cache;
  639. }
  640.  
  641. /**
  642.  * Reclaim space occupied by objects that are already free
  643.  *
  644.  * @param flags If contains SLAB_RECLAIM_ALL, do aggressive freeing
  645.  * @return Number of freed pages
  646.  */
  647. static count_t _slab_reclaim(slab_cache_t *cache, int flags)
  648. {
  649.     int i;
  650.     slab_magazine_t *mag;
  651.     count_t frames = 0;
  652.     int magcount;
  653.    
  654.     if (cache->flags & SLAB_CACHE_NOMAGAZINE)
  655.         return 0; /* Nothing to do */
  656.  
  657.     /* We count up to original magazine count to avoid
  658.      * endless loop
  659.      */
  660.     magcount = atomic_get(&cache->magazine_counter);
  661.     while (magcount-- && (mag=get_mag_from_cache(cache,0))) {
  662.         frames += magazine_destroy(cache,mag);
  663.         if (!(flags & SLAB_RECLAIM_ALL) && frames)
  664.             break;
  665.     }
  666.    
  667.     if (flags & SLAB_RECLAIM_ALL) {
  668.         /* Free cpu-bound magazines */
  669.         /* Destroy CPU magazines */
  670.         for (i=0; i<config.cpu_count; i++) {
  671.             spinlock_lock(&cache->mag_cache[i].lock);
  672.  
  673.             mag = cache->mag_cache[i].current;
  674.             if (mag)
  675.                 frames += magazine_destroy(cache, mag);
  676.             cache->mag_cache[i].current = NULL;
  677.            
  678.             mag = cache->mag_cache[i].last;
  679.             if (mag)
  680.                 frames += magazine_destroy(cache, mag);
  681.             cache->mag_cache[i].last = NULL;
  682.  
  683.             spinlock_unlock(&cache->mag_cache[i].lock);
  684.         }
  685.     }
  686.  
  687.     return frames;
  688. }
  689.  
  690. /** Check that there are no slabs and remove cache from system  */
  691. void slab_cache_destroy(slab_cache_t *cache)
  692. {
  693.     ipl_t ipl;
  694.  
  695.     /* First remove cache from link, so that we don't need
  696.      * to disable interrupts later
  697.      */
  698.  
  699.     ipl = interrupts_disable();
  700.     spinlock_lock(&slab_cache_lock);
  701.  
  702.     list_remove(&cache->link);
  703.  
  704.     spinlock_unlock(&slab_cache_lock);
  705.     interrupts_restore(ipl);
  706.  
  707.     /* Do not lock anything, we assume the software is correct and
  708.      * does not touch the cache when it decides to destroy it */
  709.    
  710.     /* Destroy all magazines */
  711.     _slab_reclaim(cache, SLAB_RECLAIM_ALL);
  712.  
  713.     /* All slabs must be empty */
  714.     if (!list_empty(&cache->full_slabs) \
  715.         || !list_empty(&cache->partial_slabs))
  716.         panic("Destroying cache that is not empty.");
  717.  
  718.     if (!(cache->flags & SLAB_CACHE_NOMAGAZINE))
  719.         free(cache->mag_cache);
  720.     slab_free(&slab_cache_cache, cache);
  721. }
  722.  
  723. /** Allocate new object from cache - if no flags given, always returns
  724.     memory */
  725. void * slab_alloc(slab_cache_t *cache, int flags)
  726. {
  727.     ipl_t ipl;
  728.     void *result = NULL;
  729.    
  730.     /* Disable interrupts to avoid deadlocks with interrupt handlers */
  731.     ipl = interrupts_disable();
  732.  
  733.     if (!(cache->flags & SLAB_CACHE_NOMAGAZINE)) {
  734.         result = magazine_obj_get(cache);
  735.     }
  736.     if (!result)
  737.         result = slab_obj_create(cache, flags);
  738.  
  739.     interrupts_restore(ipl);
  740.  
  741.     if (result)
  742.         atomic_inc(&cache->allocated_objs);
  743.  
  744.     return result;
  745. }
  746.  
  747. /** Return object to cache, use slab if known  */
  748. static void _slab_free(slab_cache_t *cache, void *obj, slab_t *slab)
  749. {
  750.     ipl_t ipl;
  751.  
  752.     ipl = interrupts_disable();
  753.  
  754.     if ((cache->flags & SLAB_CACHE_NOMAGAZINE) \
  755.         || magazine_obj_put(cache, obj)) {
  756.  
  757.         slab_obj_destroy(cache, obj, slab);
  758.  
  759.     }
  760.     interrupts_restore(ipl);
  761.     atomic_dec(&cache->allocated_objs);
  762. }
  763.  
  764. /** Return slab object to cache */
  765. void slab_free(slab_cache_t *cache, void *obj)
  766. {
  767.     _slab_free(cache,obj,NULL);
  768. }
  769.  
  770. /* Go through all caches and reclaim what is possible */
  771. count_t slab_reclaim(int flags)
  772. {
  773.     slab_cache_t *cache;
  774.     link_t *cur;
  775.     count_t frames = 0;
  776.  
  777.     spinlock_lock(&slab_cache_lock);
  778.  
  779.     /* TODO: Add assert, that interrupts are disabled, otherwise
  780.      * memory allocation from interrupts can deadlock.
  781.      */
  782.  
  783.     for (cur = slab_cache_list.next;cur!=&slab_cache_list; cur=cur->next) {
  784.         cache = list_get_instance(cur, slab_cache_t, link);
  785.         frames += _slab_reclaim(cache, flags);
  786.     }
  787.  
  788.     spinlock_unlock(&slab_cache_lock);
  789.  
  790.     return frames;
  791. }
  792.  
  793.  
  794. /* Print list of slabs */
  795. void slab_print_list(void)
  796. {
  797.     slab_cache_t *cache;
  798.     link_t *cur;
  799.     ipl_t ipl;
  800.    
  801.     ipl = interrupts_disable();
  802.     spinlock_lock(&slab_cache_lock);
  803.     printf("slab name\t  Osize\t  Pages\t Obj/pg\t  Slabs\t Cached\tAllocobjs\tCtl\n");
  804.     for (cur = slab_cache_list.next;cur!=&slab_cache_list; cur=cur->next) {
  805.         cache = list_get_instance(cur, slab_cache_t, link);
  806.         printf("%s\t%7zd\t%7zd\t%7zd\t%7zd\t%7zd\t%7zd\t\t%s\n", cache->name, cache->size,
  807.                (1 << cache->order), cache->objects,
  808.                atomic_get(&cache->allocated_slabs),
  809.                atomic_get(&cache->cached_objs),
  810.                atomic_get(&cache->allocated_objs),
  811.                cache->flags & SLAB_CACHE_SLINSIDE ? "In" : "Out");
  812.     }
  813.     spinlock_unlock(&slab_cache_lock);
  814.     interrupts_restore(ipl);
  815. }
  816.  
  817. void slab_cache_init(void)
  818. {
  819.     int i, size;
  820.  
  821.     /* Initialize magazine cache */
  822.     _slab_cache_create(&mag_cache,
  823.                "slab_magazine",
  824.                sizeof(slab_magazine_t)+SLAB_MAG_SIZE*sizeof(void*),
  825.                sizeof(__address),
  826.                NULL, NULL,
  827.                SLAB_CACHE_NOMAGAZINE | SLAB_CACHE_SLINSIDE);
  828.     /* Initialize slab_cache cache */
  829.     _slab_cache_create(&slab_cache_cache,
  830.                "slab_cache",
  831.                sizeof(slab_cache_cache),
  832.                sizeof(__address),
  833.                NULL, NULL,
  834.                SLAB_CACHE_NOMAGAZINE | SLAB_CACHE_SLINSIDE);
  835.     /* Initialize external slab cache */
  836.     slab_extern_cache = slab_cache_create("slab_extern",
  837.                           sizeof(slab_t),
  838.                           0, NULL, NULL,
  839.                           SLAB_CACHE_SLINSIDE | SLAB_CACHE_MAGDEFERRED);
  840.  
  841.     /* Initialize structures for malloc */
  842.     for (i=0, size=(1<<SLAB_MIN_MALLOC_W);
  843.          i < (SLAB_MAX_MALLOC_W-SLAB_MIN_MALLOC_W+1);
  844.          i++, size <<= 1) {
  845.         malloc_caches[i] = slab_cache_create(malloc_names[i],
  846.                              size, 0,
  847.                              NULL,NULL, SLAB_CACHE_MAGDEFERRED);
  848.     }
  849. #ifdef CONFIG_DEBUG      
  850.     _slab_initialized = 1;
  851. #endif
  852. }
  853.  
  854. /** Enable cpu_cache
  855.  *
  856.  * Kernel calls this function, when it knows the real number of
  857.  * processors.
  858.  * Allocate slab for cpucache and enable it on all existing
  859.  * slabs that are SLAB_CACHE_MAGDEFERRED
  860.  */
  861. void slab_enable_cpucache(void)
  862. {
  863.     link_t *cur;
  864.     slab_cache_t *s;
  865.  
  866. #ifdef CONFIG_DEBUG
  867.     _slab_initialized = 2;
  868. #endif
  869.  
  870.     spinlock_lock(&slab_cache_lock);
  871.    
  872.     for (cur=slab_cache_list.next; cur != &slab_cache_list;cur=cur->next){
  873.         s = list_get_instance(cur, slab_cache_t, link);
  874.         if ((s->flags & SLAB_CACHE_MAGDEFERRED) != SLAB_CACHE_MAGDEFERRED)
  875.             continue;
  876.         make_magcache(s);
  877.         s->flags &= ~SLAB_CACHE_MAGDEFERRED;
  878.     }
  879.  
  880.     spinlock_unlock(&slab_cache_lock);
  881. }
  882.  
  883. /**************************************/
  884. /* kalloc/kfree functions             */
  885. void * malloc(unsigned int size, int flags)
  886. {
  887.     int idx;
  888.  
  889.     ASSERT(_slab_initialized);
  890.     ASSERT(size && size <= (1 << SLAB_MAX_MALLOC_W));
  891.    
  892.     if (size < (1 << SLAB_MIN_MALLOC_W))
  893.         size = (1 << SLAB_MIN_MALLOC_W);
  894.  
  895.     idx = fnzb(size-1) - SLAB_MIN_MALLOC_W + 1;
  896.  
  897.     return slab_alloc(malloc_caches[idx], flags);
  898. }
  899.  
  900. void free(void *obj)
  901. {
  902.     slab_t *slab;
  903.  
  904.     if (!obj) return;
  905.  
  906.     slab = obj2slab(obj);
  907.     _slab_free(slab->cache, obj, slab);
  908. }
  909.  
  910.  /** @}
  911.  */
  912.  
  913.