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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. #include <synch/spinlock.h>
  30. #include <mm/slab.h>
  31. #include <list.h>
  32. #include <memstr.h>
  33. #include <align.h>
  34. #include <mm/heap.h>
  35. #include <mm/frame.h>
  36. #include <config.h>
  37. #include <print.h>
  38. #include <arch.h>
  39. #include <panic.h>
  40. #include <debug.h>
  41.  
  42. SPINLOCK_INITIALIZE(slab_cache_lock);
  43. LIST_INITIALIZE(slab_cache_list);
  44.  
  45. slab_cache_t mag_cache;
  46.  
  47.  
  48. typedef struct {
  49.     slab_cache_t *cache; /**< Pointer to parent cache */
  50.     link_t link;       /* List of full/partial slabs */
  51.     void *start;       /**< Start address of first available item */
  52.     count_t available; /**< Count of available items in this slab */
  53.     index_t nextavail; /**< The index of next available item */
  54. }slab_t;
  55.  
  56. /**************************************/
  57. /* SLAB allocation functions          */
  58.  
  59. /**
  60.  * Allocate frames for slab space and initialize
  61.  *
  62.  * TODO: Change slab_t allocation to slab_alloc(????), malloc with flags!!
  63.  */
  64. static slab_t * slab_space_alloc(slab_cache_t *cache, int flags)
  65. {
  66.     void *data;
  67.     slab_t *slab;
  68.     size_t fsize;
  69.     int i;
  70.     zone_t *zone = NULL;
  71.     int status;
  72.     frame_t *frame;
  73.  
  74.     data = (void *)frame_alloc(FRAME_KA | flags, cache->order, &status, &zone);
  75.     if (status != FRAME_OK) {
  76.         return NULL;
  77.     }
  78.     if (! cache->flags & SLAB_CACHE_SLINSIDE) {
  79.         slab = malloc(sizeof(*slab)); // , flags);
  80.         if (!slab) {
  81.             frame_free((__address)data);
  82.             return NULL;
  83.         }
  84.     } else {
  85.         fsize = (PAGE_SIZE << cache->order);
  86.         slab = data + fsize - sizeof(*slab);
  87.     }
  88.        
  89.     /* Fill in slab structures */
  90.     /* TODO: some better way of accessing the frame */
  91.     for (i=0; i< (1<<cache->order); i++) {
  92.         frame = ADDR2FRAME(zone, KA2PA((__address)(data+i*PAGE_SIZE)));
  93.         frame->parent = slab;
  94.     }
  95.  
  96.     slab->start = data;
  97.     slab->available = cache->objects;
  98.     slab->nextavail = 0;
  99.  
  100.     for (i=0; i<cache->objects;i++)
  101.         *((int *) (slab->start + i*cache->size)) = i+1;
  102.  
  103.     atomic_inc(&cache->allocated_slabs);
  104.  
  105.     return slab;
  106. }
  107.  
  108. /**
  109.  * Free space associated with SLAB
  110.  *
  111.  * @return number of freed frames
  112.  */
  113. static count_t slab_space_free(slab_cache_t *cache, slab_t *slab)
  114. {
  115.     frame_free((__address)slab->start);
  116.     if (! cache->flags & SLAB_CACHE_SLINSIDE)
  117.         free(slab);
  118.  
  119.     atomic_dec(&cache->allocated_slabs);
  120.    
  121.     return 1 << cache->order;
  122. }
  123.  
  124. /** Map object to slab structure */
  125. static slab_t * obj2slab(void *obj)
  126. {
  127.     frame_t *frame;
  128.  
  129.     frame = frame_addr2frame((__address)obj);
  130.     return (slab_t *)frame->parent;
  131. }
  132.  
  133. /**************************************/
  134. /* SLAB functions */
  135.  
  136.  
  137. /**
  138.  * Return object to slab and call a destructor
  139.  *
  140.  * Assume the cache->lock is held;
  141.  *
  142.  * @param slab If the caller knows directly slab of the object, otherwise NULL
  143.  *
  144.  * @return Number of freed pages
  145.  */
  146. static count_t slab_obj_destroy(slab_cache_t *cache, void *obj,
  147.                 slab_t *slab)
  148. {
  149.     count_t frames = 0;
  150.  
  151.     if (!slab)
  152.         slab = obj2slab(obj);
  153.  
  154.     spinlock_lock(&cache->lock);
  155.  
  156.     *((int *)obj) = slab->nextavail;
  157.     slab->nextavail = (obj - slab->start)/cache->size;
  158.     slab->available++;
  159.  
  160.     /* Move it to correct list */
  161.     if (slab->available == 1) {
  162.         /* It was in full, move to partial */
  163.         list_remove(&slab->link);
  164.         list_prepend(&slab->link, &cache->partial_slabs);
  165.     }
  166.     if (slab->available == cache->objects) {
  167.         /* Free associated memory */
  168.         list_remove(&slab->link);
  169.         /* Avoid deadlock */
  170.         spinlock_unlock(&cache->lock);
  171.         frames = slab_space_free(cache, slab);
  172.         spinlock_lock(&cache->lock);
  173.     }
  174.  
  175.     spinlock_unlock(&cache->lock);
  176.  
  177.     return frames;
  178. }
  179.  
  180. /**
  181.  * Take new object from slab or create new if needed
  182.  *
  183.  * Assume cache->lock is held.
  184.  *
  185.  * @return Object address or null
  186.  */
  187. static void * slab_obj_create(slab_cache_t *cache, int flags)
  188. {
  189.     slab_t *slab;
  190.     void *obj;
  191.  
  192.     if (list_empty(&cache->partial_slabs)) {
  193.         /* Allow recursion and reclaiming
  194.          * - this should work, as the SLAB control structures
  195.          *   are small and do not need to allocte with anything
  196.          *   other ten frame_alloc when they are allocating,
  197.          *   that's why we should get recursion at most 1-level deep
  198.          */
  199.         spinlock_unlock(&cache->lock);
  200.         slab = slab_space_alloc(cache, flags);
  201.         spinlock_lock(&cache->lock);
  202.         if (!slab) {
  203.             return NULL;
  204.         }
  205.     } else {
  206.         slab = list_get_instance(cache->partial_slabs.next,
  207.                      slab_t,
  208.                      link);
  209.         list_remove(&slab->link);
  210.     }
  211.     obj = slab->start + slab->nextavail * cache->size;
  212.     slab->nextavail = *((int *)obj);
  213.     slab->available--;
  214.     if (! slab->available)
  215.         list_prepend(&slab->link, &cache->full_slabs);
  216.     else
  217.         list_prepend(&slab->link, &cache->partial_slabs);
  218.     return obj;
  219. }
  220.  
  221. /**************************************/
  222. /* CPU-Cache slab functions */
  223.  
  224. /**
  225.  * Free all objects in magazine and free memory associated with magazine
  226.  *
  227.  * Assume mag_cache[cpu].lock is locked
  228.  *
  229.  * @return Number of freed pages
  230.  */
  231. static count_t magazine_destroy(slab_cache_t *cache,
  232.                 slab_magazine_t *mag)
  233. {
  234.     int i;
  235.     count_t frames = 0;
  236.  
  237.     for (i=0;i < mag->busy; i++)
  238.         frames += slab_obj_destroy(cache, mag->objs[i], NULL);
  239.    
  240.     slab_free(&mag_cache, mag);
  241.  
  242.     return frames;
  243. }
  244.  
  245. /**
  246.  * Try to find object in CPU-cache magazines
  247.  *
  248.  * @return Pointer to object or NULL if not available
  249.  */
  250. static void * magazine_obj_get(slab_cache_t *cache)
  251. {
  252.     slab_magazine_t *mag;
  253.  
  254.     spinlock_lock(&cache->mag_cache[CPU->id].lock);
  255.  
  256.     mag = cache->mag_cache[CPU->id].current;
  257.     if (!mag)
  258.         goto out;
  259.  
  260.     if (!mag->busy) {
  261.         /* If current is empty && last exists && not empty, exchange */
  262.         if (cache->mag_cache[CPU->id].last \
  263.             && cache->mag_cache[CPU->id].last->busy) {
  264.             cache->mag_cache[CPU->id].current = cache->mag_cache[CPU->id].last;
  265.             cache->mag_cache[CPU->id].last = mag;
  266.             mag = cache->mag_cache[CPU->id].current;
  267.             goto gotit;
  268.         }
  269.         /* If still not busy, exchange current with some from
  270.          * other full magazines */
  271.         spinlock_lock(&cache->lock);
  272.         if (list_empty(&cache->magazines)) {
  273.             spinlock_unlock(&cache->lock);
  274.             goto out;
  275.         }
  276.         /* Free current magazine and take one from list */
  277.         slab_free(&mag_cache, mag);
  278.         mag = list_get_instance(cache->magazines.next,
  279.                     slab_magazine_t,
  280.                     link);
  281.         list_remove(&mag->link);
  282.        
  283.         spinlock_unlock(&cache->lock);
  284.     }
  285. gotit:
  286.     spinlock_unlock(&cache->mag_cache[CPU->id].lock);
  287.     return mag->objs[--mag->busy];
  288. out:   
  289.     spinlock_unlock(&cache->mag_cache[CPU->id].lock);
  290.     return NULL;
  291. }
  292.  
  293. /**
  294.  * Put object into CPU-cache magazine
  295.  *
  296.  * We have 2 magazines bound to processor.
  297.  * First try the current.
  298.  *  If full, try the last.
  299.  *   If full, put to magazines list.
  300.  *   allocate new, exchange last & current
  301.  *
  302.  * @return 0 - success, -1 - could not get memory
  303.  */
  304. static int magazine_obj_put(slab_cache_t *cache, void *obj)
  305. {
  306.     slab_magazine_t *mag;
  307.  
  308.     spinlock_lock(&cache->mag_cache[CPU->id].lock);
  309.    
  310.     mag = cache->mag_cache[CPU->id].current;
  311.     if (!mag) {
  312.         /* We do not want to sleep just because of caching */
  313.         /* Especially we do not want reclaiming to start, as
  314.          * this would deadlock */
  315.         mag = slab_alloc(&mag_cache, FRAME_ATOMIC | FRAME_NO_RECLAIM);
  316.         if (!mag) /* Allocation failed, give up on caching */
  317.             goto errout;
  318.  
  319.         cache->mag_cache[CPU->id].current = mag;
  320.         mag->size = SLAB_MAG_SIZE;
  321.         mag->busy = 0;
  322.     } else if (mag->busy == mag->size) {
  323.         /* If the last is full | empty, allocate new */
  324.         mag = cache->mag_cache[CPU->id].last;
  325.         if (!mag || mag->size == mag->busy) {
  326.             if (mag)
  327.                 list_prepend(&mag->link, &cache->magazines);
  328.  
  329.             mag = slab_alloc(&mag_cache, FRAME_ATOMIC | FRAME_NO_RECLAIM);
  330.             if (!mag)
  331.                 goto errout;
  332.            
  333.             mag->size = SLAB_MAG_SIZE;
  334.             mag->busy = 0;
  335.             cache->mag_cache[CPU->id].last = mag;
  336.         }
  337.         /* Exchange the 2 */
  338.         cache->mag_cache[CPU->id].last = cache->mag_cache[CPU->id].current;
  339.         cache->mag_cache[CPU->id].current = mag;
  340.     }
  341.     mag->objs[mag->busy++] = obj;
  342.  
  343.     spinlock_unlock(&cache->mag_cache[CPU->id].lock);
  344.     return 0;
  345. errout:
  346.     spinlock_unlock(&cache->mag_cache[CPU->id].lock);
  347.     return -1;
  348. }
  349.  
  350.  
  351. /**************************************/
  352. /* SLAB CACHE functions */
  353.  
  354. /** Return number of objects that fit in certain cache size */
  355. static int comp_objects(slab_cache_t *cache)
  356. {
  357.     if (cache->flags & SLAB_CACHE_SLINSIDE)
  358.         return ((PAGE_SIZE << cache->order) - sizeof(slab_t)) / cache->size;
  359.     else
  360.         return (PAGE_SIZE << cache->order) / cache->size;
  361. }
  362.  
  363. /** Return wasted space in slab */
  364. static int badness(slab_cache_t *cache)
  365. {
  366.     int objects;
  367.     int ssize;
  368.  
  369.     objects = comp_objects(cache);
  370.     ssize = PAGE_SIZE << cache->order;
  371.     if (cache->flags & SLAB_CACHE_SLINSIDE)
  372.         ssize -= sizeof(slab_t);
  373.     return ssize - objects*cache->size;
  374. }
  375.  
  376. /** Initialize allocated memory as a slab cache */
  377. static void
  378. _slab_cache_create(slab_cache_t *cache,
  379.            char *name,
  380.            size_t size,
  381.            size_t align,
  382.            int (*constructor)(void *obj, int kmflag),
  383.            void (*destructor)(void *obj),
  384.            int flags)
  385. {
  386.     int i;
  387.  
  388.     memsetb((__address)cache, sizeof(*cache), 0);
  389.     cache->name = name;
  390.  
  391.     if (align)
  392.         size = ALIGN_UP(size, align);
  393.     cache->size = size;
  394.  
  395.     cache->constructor = constructor;
  396.     cache->destructor = destructor;
  397.     cache->flags = flags;
  398.  
  399.     list_initialize(&cache->full_slabs);
  400.     list_initialize(&cache->partial_slabs);
  401.     list_initialize(&cache->magazines);
  402.     spinlock_initialize(&cache->lock, "cachelock");
  403.     if (! cache->flags & SLAB_CACHE_NOMAGAZINE) {
  404.         for (i=0; i< config.cpu_count; i++)
  405.             spinlock_initialize(&cache->mag_cache[i].lock,
  406.                         "cpucachelock");
  407.     }
  408.  
  409.     /* Compute slab sizes, object counts in slabs etc. */
  410.     if (cache->size < SLAB_INSIDE_SIZE)
  411.         cache->flags |= SLAB_CACHE_SLINSIDE;
  412.  
  413.     /* Minimum slab order */
  414.     cache->order = (cache->size >> PAGE_WIDTH) + 1;
  415.        
  416.     while (badness(cache) > SLAB_MAX_BADNESS(cache)) {
  417.         cache->order += 1;
  418.     }
  419.  
  420.     cache->objects = comp_objects(cache);
  421.  
  422.     spinlock_lock(&slab_cache_lock);
  423.  
  424.     list_append(&cache->link, &slab_cache_list);
  425.  
  426.     spinlock_unlock(&slab_cache_lock);
  427. }
  428.  
  429. /** Create slab cache  */
  430. slab_cache_t * slab_cache_create(char *name,
  431.                  size_t size,
  432.                  size_t align,
  433.                  int (*constructor)(void *obj, int kmflag),
  434.                  void (*destructor)(void *obj),
  435.                  int flags)
  436. {
  437.     slab_cache_t *cache;
  438.  
  439.     cache = malloc(sizeof(*cache) + config.cpu_count*sizeof(cache->mag_cache[0]));
  440.     _slab_cache_create(cache, name, size, align, constructor, destructor,
  441.                flags);
  442.     return cache;
  443. }
  444.  
  445. /**
  446.  * Reclaim space occupied by objects that are already free
  447.  *
  448.  * @param flags If contains SLAB_RECLAIM_ALL, do aggressive freeing
  449.  * @return Number of freed pages
  450.  *
  451.  * TODO: Add light reclaim
  452.  */
  453. static count_t _slab_reclaim(slab_cache_t *cache, int flags)
  454. {
  455.     int i;
  456.     slab_magazine_t *mag;
  457.     link_t *cur;
  458.     count_t frames = 0;
  459.    
  460.     if (cache->flags & SLAB_CACHE_NOMAGAZINE)
  461.         return 0; /* Nothing to do */
  462.    
  463.     /* First lock all cpu caches, then the complete cache lock */
  464.     for (i=0; i < config.cpu_count; i++)
  465.         spinlock_lock(&cache->mag_cache[i].lock);
  466.     spinlock_lock(&cache->lock);
  467.    
  468.     if (flags & SLAB_RECLAIM_ALL) {
  469.         /* Aggressive memfree */
  470.  
  471.         /* Destroy CPU magazines */
  472.         for (i=0; i<config.cpu_count; i++) {
  473.             mag = cache->mag_cache[i].current;
  474.             if (mag)
  475.                 frames += magazine_destroy(cache, mag);
  476.             cache->mag_cache[i].current = NULL;
  477.            
  478.             mag = cache->mag_cache[i].last;
  479.             if (mag)
  480.                 frames += magazine_destroy(cache, mag);
  481.             cache->mag_cache[i].last = NULL;
  482.         }
  483.     }
  484.     /* Destroy full magazines */
  485.     cur=cache->magazines.prev;
  486.     while (cur!=&cache->magazines) {
  487.         mag = list_get_instance(cur, slab_magazine_t, link);
  488.        
  489.         cur = cur->prev;
  490.         list_remove(cur->next);
  491.         frames += magazine_destroy(cache,mag);
  492.         /* If we do not do full reclaim, break
  493.          * as soon as something is freed */
  494.         if (!(flags & SLAB_RECLAIM_ALL) && frames)
  495.             break;
  496.     }
  497.    
  498.     spinlock_unlock(&cache->lock);
  499.     for (i=0; i < config.cpu_count; i++)
  500.         spinlock_unlock(&cache->mag_cache[i].lock);
  501.    
  502.     return frames;
  503. }
  504.  
  505. /** Check that there are no slabs and remove cache from system  */
  506. void slab_cache_destroy(slab_cache_t *cache)
  507. {
  508.     /* Do not lock anything, we assume the software is correct and
  509.      * does not touch the cache when it decides to destroy it */
  510.    
  511.     /* Destroy all magazines */
  512.     _slab_reclaim(cache, SLAB_RECLAIM_ALL);
  513.  
  514.     /* All slabs must be empty */
  515.     if (!list_empty(&cache->full_slabs) \
  516.         || !list_empty(&cache->partial_slabs))
  517.         panic("Destroying cache that is not empty.");
  518.  
  519.     spinlock_lock(&slab_cache_lock);
  520.     list_remove(&cache->link);
  521.     spinlock_unlock(&slab_cache_lock);
  522.  
  523.     free(cache);
  524. }
  525.  
  526. /** Allocate new object from cache - if no flags given, always returns
  527.     memory */
  528. void * slab_alloc(slab_cache_t *cache, int flags)
  529. {
  530.     ipl_t ipl;
  531.     void *result = NULL;
  532.  
  533.     /* Disable interrupts to avoid deadlocks with interrupt handlers */
  534.     ipl = interrupts_disable();
  535.    
  536.     if (!cache->flags & SLAB_CACHE_NOMAGAZINE)
  537.         result = magazine_obj_get(cache);
  538.  
  539.     if (!result) {
  540.         spinlock_lock(&cache->lock);
  541.         result = slab_obj_create(cache, flags);
  542.         spinlock_unlock(&cache->lock);
  543.     }
  544.  
  545.     if (result)
  546.         atomic_inc(&cache->allocated_objs);
  547.  
  548.     interrupts_restore(ipl);
  549.  
  550.  
  551.     return result;
  552. }
  553.  
  554. /** Return object to cache  */
  555. void slab_free(slab_cache_t *cache, void *obj)
  556. {
  557.     ipl_t ipl;
  558.  
  559.     ipl = interrupts_disable();
  560.  
  561.     if ((cache->flags & SLAB_CACHE_NOMAGAZINE) \
  562.         || magazine_obj_put(cache, obj)) {
  563.        
  564.         spinlock_lock(&cache->lock);
  565.         slab_obj_destroy(cache, obj, NULL);
  566.         spinlock_unlock(&cache->lock);
  567.     }
  568.     atomic_dec(&cache->allocated_objs);
  569.     interrupts_restore(ipl);
  570. }
  571.  
  572. /* Go through all caches and reclaim what is possible */
  573. count_t slab_reclaim(int flags)
  574. {
  575.     slab_cache_t *cache;
  576.     link_t *cur;
  577.     count_t frames = 0;
  578.  
  579.     spinlock_lock(&slab_cache_lock);
  580.  
  581.     for (cur = slab_cache_list.next;cur!=&slab_cache_list; cur=cur->next) {
  582.         cache = list_get_instance(cur, slab_cache_t, link);
  583.         frames += _slab_reclaim(cache, flags);
  584.     }
  585.  
  586.     spinlock_unlock(&slab_cache_lock);
  587.  
  588.     return frames;
  589. }
  590.  
  591.  
  592. /* Print list of slabs */
  593. void slab_print_list(void)
  594. {
  595.     slab_cache_t *cache;
  596.     link_t *cur;
  597.  
  598.     spinlock_lock(&slab_cache_lock);
  599.     printf("SLAB name\tOsize\tOrder\tOcnt\tSlabs\tAllocobjs\n");
  600.     for (cur = slab_cache_list.next;cur!=&slab_cache_list; cur=cur->next) {
  601.         cache = list_get_instance(cur, slab_cache_t, link);
  602.         printf("%s\t%d\t%d\t%d\t%d\t%d\n", cache->name, cache->size,
  603.                cache->order, cache->objects,
  604.                atomic_get(&cache->allocated_slabs),
  605.                atomic_get(&cache->allocated_objs));
  606.     }
  607.     spinlock_unlock(&slab_cache_lock);
  608. }
  609.  
  610. void slab_cache_init(void)
  611. {
  612.     /* Initialize magazine cache */
  613.     _slab_cache_create(&mag_cache,
  614.                "slab_magazine",
  615.                sizeof(slab_magazine_t)+SLAB_MAG_SIZE*sizeof(void*),
  616.                sizeof(__address),
  617.                NULL, NULL,
  618.                SLAB_CACHE_NOMAGAZINE);
  619.  
  620.     /* Initialize structures for malloc */
  621. }
  622.