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