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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.     slab->cache = cache;
  100.  
  101.     for (i=0; i<cache->objects;i++)
  102.         *((int *) (slab->start + i*cache->size)) = i+1;
  103.  
  104.     atomic_inc(&cache->allocated_slabs);
  105.     return slab;
  106. }
  107.  
  108. /**
  109.  * Deallocate 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.     ASSERT(slab->cache == cache);
  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.     return frames;
  176. }
  177.  
  178. /**
  179.  * Take new object from slab or create new if needed
  180.  *
  181.  * Assume cache->lock is held.
  182.  *
  183.  * @return Object address or null
  184.  */
  185. static void * slab_obj_create(slab_cache_t *cache, int flags)
  186. {
  187.     slab_t *slab;
  188.     void *obj;
  189.  
  190.     if (list_empty(&cache->partial_slabs)) {
  191.         /* Allow recursion and reclaiming
  192.          * - this should work, as the SLAB control structures
  193.          *   are small and do not need to allocte with anything
  194.          *   other ten frame_alloc when they are allocating,
  195.          *   that's why we should get recursion at most 1-level deep
  196.          */
  197.         spinlock_unlock(&cache->lock);
  198.         slab = slab_space_alloc(cache, flags);
  199.         spinlock_lock(&cache->lock);
  200.         if (!slab) {
  201.             return NULL;
  202.         }
  203.     } else {
  204.         slab = list_get_instance(cache->partial_slabs.next,
  205.                      slab_t,
  206.                      link);
  207.         list_remove(&slab->link);
  208.     }
  209.     obj = slab->start + slab->nextavail * cache->size;
  210.     slab->nextavail = *((int *)obj);
  211.     slab->available--;
  212.     if (! slab->available)
  213.         list_prepend(&slab->link, &cache->full_slabs);
  214.     else
  215.         list_prepend(&slab->link, &cache->partial_slabs);
  216.     return obj;
  217. }
  218.  
  219. /**************************************/
  220. /* CPU-Cache slab functions */
  221.  
  222. /**
  223.  * Free all objects in magazine and free memory associated with magazine
  224.  *
  225.  * Assume mag_cache[cpu].lock is locked
  226.  *
  227.  * @return Number of freed pages
  228.  */
  229. static count_t magazine_destroy(slab_cache_t *cache,
  230.                 slab_magazine_t *mag)
  231. {
  232.     int i;
  233.     count_t frames = 0;
  234.  
  235.     for (i=0;i < mag->busy; i++) {
  236.         frames += slab_obj_destroy(cache, mag->objs[i], NULL);
  237.         atomic_dec(&cache->cached_objs);
  238.     }
  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.     void *obj;
  254.  
  255.     spinlock_lock(&cache->mag_cache[CPU->id].lock);
  256.  
  257.     mag = cache->mag_cache[CPU->id].current;
  258.     if (!mag)
  259.         goto out;
  260.  
  261.     if (!mag->busy) {
  262.         /* If current is empty && last exists && not empty, exchange */
  263.         if (cache->mag_cache[CPU->id].last \
  264.             && cache->mag_cache[CPU->id].last->busy) {
  265.             cache->mag_cache[CPU->id].current = cache->mag_cache[CPU->id].last;
  266.             cache->mag_cache[CPU->id].last = mag;
  267.             mag = cache->mag_cache[CPU->id].current;
  268.             goto gotit;
  269.         }
  270.         /* If still not busy, exchange current with some from
  271.          * other full magazines */
  272.         spinlock_lock(&cache->lock);
  273.         if (list_empty(&cache->magazines)) {
  274.             spinlock_unlock(&cache->lock);
  275.             goto out;
  276.         }
  277.         /* Free current magazine and take one from list */
  278.         slab_free(&mag_cache, mag);
  279.  
  280.         mag = list_get_instance(cache->magazines.next,
  281.                     slab_magazine_t,
  282.                     link);
  283.         list_remove(&mag->link);
  284.        
  285.         spinlock_unlock(&cache->lock);
  286.     }
  287. gotit:
  288.     obj = mag->objs[--mag->busy];
  289.     spinlock_unlock(&cache->mag_cache[CPU->id].lock);
  290.     atomic_dec(&cache->cached_objs);
  291.    
  292.     return obj;
  293. out:   
  294.     spinlock_unlock(&cache->mag_cache[CPU->id].lock);
  295.     return NULL;
  296. }
  297.  
  298. /**
  299.  * Assure that the current magazine is empty, return pointer to it, or NULL if
  300.  * no empty magazine available and cannot be allocated
  301.  *
  302.  * We have 2 magazines bound to processor.
  303.  * First try the current.
  304.  *  If full, try the last.
  305.  *   If full, put to magazines list.
  306.  *   allocate new, exchange last & current
  307.  *
  308.  */
  309. static slab_magazine_t * make_empty_current_mag(slab_cache_t *cache)
  310. {
  311.     slab_magazine_t *cmag,*lastmag,*newmag;
  312.  
  313.     cmag = cache->mag_cache[CPU->id].current;
  314.     lastmag = cache->mag_cache[CPU->id].last;
  315.  
  316.     if (cmag) {
  317.         if (cmag->busy < cmag->size)
  318.             return cmag;
  319.         if (lastmag && lastmag->busy < lastmag->size) {
  320.             cache->mag_cache[CPU->id].last = cmag;
  321.             cache->mag_cache[CPU->id].current = lastmag;
  322.             return lastmag;
  323.         }
  324.     }
  325.     /* current | last are full | nonexistent, allocate new */
  326.     /* We do not want to sleep just because of caching */
  327.     /* Especially we do not want reclaiming to start, as
  328.      * this would deadlock */
  329.     newmag = slab_alloc(&mag_cache, FRAME_ATOMIC | FRAME_NO_RECLAIM);
  330.     if (!newmag)
  331.         return NULL;
  332.     newmag->size = SLAB_MAG_SIZE;
  333.     newmag->busy = 0;
  334.  
  335.     /* Flush last to magazine list */
  336.     if (lastmag)
  337.         list_prepend(&lastmag->link, &cache->magazines);
  338.     /* Move current as last, save new as current */
  339.     cache->mag_cache[CPU->id].last = cmag; 
  340.     cache->mag_cache[CPU->id].current = newmag;
  341.  
  342.     return newmag;
  343. }
  344.  
  345. /**
  346.  * Put object into CPU-cache magazine
  347.  *
  348.  * @return 0 - success, -1 - could not get memory
  349.  */
  350. static int magazine_obj_put(slab_cache_t *cache, void *obj)
  351. {
  352.     slab_magazine_t *mag;
  353.  
  354.     spinlock_lock(&cache->mag_cache[CPU->id].lock);
  355.  
  356.     mag = make_empty_current_mag(cache);
  357.     if (!mag)
  358.         goto errout;
  359.    
  360.     mag->objs[mag->busy++] = obj;
  361.  
  362.     spinlock_unlock(&cache->mag_cache[CPU->id].lock);
  363.     atomic_inc(&cache->cached_objs);
  364.     return 0;
  365. errout:
  366.     spinlock_unlock(&cache->mag_cache[CPU->id].lock);
  367.     return -1;
  368. }
  369.  
  370.  
  371. /**************************************/
  372. /* SLAB CACHE functions */
  373.  
  374. /** Return number of objects that fit in certain cache size */
  375. static int comp_objects(slab_cache_t *cache)
  376. {
  377.     if (cache->flags & SLAB_CACHE_SLINSIDE)
  378.         return ((PAGE_SIZE << cache->order) - sizeof(slab_t)) / cache->size;
  379.     else
  380.         return (PAGE_SIZE << cache->order) / cache->size;
  381. }
  382.  
  383. /** Return wasted space in slab */
  384. static int badness(slab_cache_t *cache)
  385. {
  386.     int objects;
  387.     int ssize;
  388.  
  389.     objects = comp_objects(cache);
  390.     ssize = PAGE_SIZE << cache->order;
  391.     if (cache->flags & SLAB_CACHE_SLINSIDE)
  392.         ssize -= sizeof(slab_t);
  393.     return ssize - objects*cache->size;
  394. }
  395.  
  396. /** Initialize allocated memory as a slab cache */
  397. static void
  398. _slab_cache_create(slab_cache_t *cache,
  399.            char *name,
  400.            size_t size,
  401.            size_t align,
  402.            int (*constructor)(void *obj, int kmflag),
  403.            void (*destructor)(void *obj),
  404.            int flags)
  405. {
  406.     int i;
  407.  
  408.     memsetb((__address)cache, sizeof(*cache), 0);
  409.     cache->name = name;
  410.  
  411.     if (align < sizeof(__native))
  412.         align = sizeof(__native);
  413.     size = ALIGN_UP(size, align);
  414.        
  415.     cache->size = size;
  416.  
  417.     cache->constructor = constructor;
  418.     cache->destructor = destructor;
  419.     cache->flags = flags;
  420.  
  421.     list_initialize(&cache->full_slabs);
  422.     list_initialize(&cache->partial_slabs);
  423.     list_initialize(&cache->magazines);
  424.     spinlock_initialize(&cache->lock, "cachelock");
  425.     if (! (cache->flags & SLAB_CACHE_NOMAGAZINE)) {
  426.         for (i=0; i< config.cpu_count; i++)
  427.             spinlock_initialize(&cache->mag_cache[i].lock,
  428.                         "cpucachelock");
  429.     }
  430.  
  431.     /* Compute slab sizes, object counts in slabs etc. */
  432.     if (cache->size < SLAB_INSIDE_SIZE)
  433.         cache->flags |= SLAB_CACHE_SLINSIDE;
  434.  
  435.     /* Minimum slab order */
  436.     cache->order = (cache->size-1) >> PAGE_WIDTH;
  437.  
  438.     while (badness(cache) > SLAB_MAX_BADNESS(cache)) {
  439.         cache->order += 1;
  440.     }
  441.     cache->objects = comp_objects(cache);
  442.     /* If info fits in, put it inside */
  443.     if (badness(cache) > sizeof(slab_t))
  444.         cache->flags |= SLAB_CACHE_SLINSIDE;
  445.  
  446.     spinlock_lock(&slab_cache_lock);
  447.  
  448.     list_append(&cache->link, &slab_cache_list);
  449.  
  450.     spinlock_unlock(&slab_cache_lock);
  451. }
  452.  
  453. /** Create slab cache  */
  454. slab_cache_t * slab_cache_create(char *name,
  455.                  size_t size,
  456.                  size_t align,
  457.                  int (*constructor)(void *obj, int kmflag),
  458.                  void (*destructor)(void *obj),
  459.                  int flags)
  460. {
  461.     slab_cache_t *cache;
  462.  
  463.     cache = malloc(sizeof(*cache) + config.cpu_count*sizeof(cache->mag_cache[0]));
  464.     _slab_cache_create(cache, name, size, align, constructor, destructor,
  465.                flags);
  466.     return cache;
  467. }
  468.  
  469. /**
  470.  * Reclaim space occupied by objects that are already free
  471.  *
  472.  * @param flags If contains SLAB_RECLAIM_ALL, do aggressive freeing
  473.  * @return Number of freed pages
  474.  */
  475. static count_t _slab_reclaim(slab_cache_t *cache, int flags)
  476. {
  477.     int i;
  478.     slab_magazine_t *mag;
  479.     link_t *cur;
  480.     count_t frames = 0;
  481.    
  482.     if (cache->flags & SLAB_CACHE_NOMAGAZINE)
  483.         return 0; /* Nothing to do */
  484.    
  485.     /* First lock all cpu caches, then the complete cache lock */
  486.     for (i=0; i < config.cpu_count; i++)
  487.         spinlock_lock(&cache->mag_cache[i].lock);
  488.     spinlock_lock(&cache->lock);
  489.    
  490.     if (flags & SLAB_RECLAIM_ALL) {
  491.         /* Aggressive memfree */
  492.         /* Destroy CPU magazines */
  493.         for (i=0; i<config.cpu_count; i++) {
  494.             mag = cache->mag_cache[i].current;
  495.             if (mag)
  496.                 frames += magazine_destroy(cache, mag);
  497.             cache->mag_cache[i].current = NULL;
  498.            
  499.             mag = cache->mag_cache[i].last;
  500.             if (mag)
  501.                 frames += magazine_destroy(cache, mag);
  502.             cache->mag_cache[i].last = NULL;
  503.         }
  504.     }
  505.     /* Destroy full magazines */
  506.     cur=cache->magazines.prev;
  507.  
  508.     while (cur != &cache->magazines) {
  509.         mag = list_get_instance(cur, slab_magazine_t, link);
  510.        
  511.         cur = cur->prev;
  512.         list_remove(&mag->link);
  513.         frames += magazine_destroy(cache,mag);
  514.         /* If we do not do full reclaim, break
  515.          * as soon as something is freed */
  516.         if (!(flags & SLAB_RECLAIM_ALL) && frames)
  517.             break;
  518.     }
  519.    
  520.     spinlock_unlock(&cache->lock);
  521.     for (i=0; i < config.cpu_count; i++)
  522.         spinlock_unlock(&cache->mag_cache[i].lock);
  523.    
  524.     return frames;
  525. }
  526.  
  527. /** Check that there are no slabs and remove cache from system  */
  528. void slab_cache_destroy(slab_cache_t *cache)
  529. {
  530.     /* Do not lock anything, we assume the software is correct and
  531.      * does not touch the cache when it decides to destroy it */
  532.    
  533.     /* Destroy all magazines */
  534.     _slab_reclaim(cache, SLAB_RECLAIM_ALL);
  535.  
  536.     /* All slabs must be empty */
  537.     if (!list_empty(&cache->full_slabs) \
  538.         || !list_empty(&cache->partial_slabs))
  539.         panic("Destroying cache that is not empty.");
  540.  
  541.     spinlock_lock(&slab_cache_lock);
  542.     list_remove(&cache->link);
  543.     spinlock_unlock(&slab_cache_lock);
  544.  
  545.     free(cache);
  546. }
  547.  
  548. /** Allocate new object from cache - if no flags given, always returns
  549.     memory */
  550. void * slab_alloc(slab_cache_t *cache, int flags)
  551. {
  552.     ipl_t ipl;
  553.     void *result = NULL;
  554.  
  555.     /* Disable interrupts to avoid deadlocks with interrupt handlers */
  556.     ipl = interrupts_disable();
  557.    
  558.     if (!(cache->flags & SLAB_CACHE_NOMAGAZINE))
  559.         result = magazine_obj_get(cache);
  560.  
  561.     if (!result) {
  562.         spinlock_lock(&cache->lock);
  563.         result = slab_obj_create(cache, flags);
  564.         spinlock_unlock(&cache->lock);
  565.     }
  566.  
  567.     if (result)
  568.         atomic_inc(&cache->allocated_objs);
  569.  
  570.     interrupts_restore(ipl);
  571.  
  572.  
  573.     return result;
  574. }
  575.  
  576. /** Return object to cache  */
  577. void slab_free(slab_cache_t *cache, void *obj)
  578. {
  579.     ipl_t ipl;
  580.  
  581.     ipl = interrupts_disable();
  582.  
  583.     if ((cache->flags & SLAB_CACHE_NOMAGAZINE) \
  584.         || magazine_obj_put(cache, obj)) {
  585.        
  586.         spinlock_lock(&cache->lock);
  587.         slab_obj_destroy(cache, obj, NULL);
  588.         spinlock_unlock(&cache->lock);
  589.     }
  590.     atomic_dec(&cache->allocated_objs);
  591.     interrupts_restore(ipl);
  592. }
  593.  
  594. /* Go through all caches and reclaim what is possible */
  595. count_t slab_reclaim(int flags)
  596. {
  597.     slab_cache_t *cache;
  598.     link_t *cur;
  599.     count_t frames = 0;
  600.  
  601.     spinlock_lock(&slab_cache_lock);
  602.  
  603.     for (cur = slab_cache_list.next;cur!=&slab_cache_list; cur=cur->next) {
  604.         cache = list_get_instance(cur, slab_cache_t, link);
  605.         frames += _slab_reclaim(cache, flags);
  606.     }
  607.  
  608.     spinlock_unlock(&slab_cache_lock);
  609.  
  610.     return frames;
  611. }
  612.  
  613.  
  614. /* Print list of slabs */
  615. void slab_print_list(void)
  616. {
  617.     slab_cache_t *cache;
  618.     link_t *cur;
  619.  
  620.     spinlock_lock(&slab_cache_lock);
  621.     printf("SLAB name\tOsize\tPages\tObj/pg\tSlabs\tCached\tAllocobjs\tCtl\n");
  622.     for (cur = slab_cache_list.next;cur!=&slab_cache_list; cur=cur->next) {
  623.         cache = list_get_instance(cur, slab_cache_t, link);
  624.         printf("%s\t%d\t%d\t%d\t%d\t%d\t%d\t\t%s\n", cache->name, cache->size,
  625.                (1 << cache->order), cache->objects,
  626.                atomic_get(&cache->allocated_slabs),
  627.                atomic_get(&cache->cached_objs),
  628.                atomic_get(&cache->allocated_objs),
  629.                cache->flags & SLAB_CACHE_SLINSIDE ? "In" : "Out");
  630.     }
  631.     spinlock_unlock(&slab_cache_lock);
  632. }
  633.  
  634. void slab_cache_init(void)
  635. {
  636.     /* Initialize magazine cache */
  637.     _slab_cache_create(&mag_cache,
  638.                "slab_magazine",
  639.                sizeof(slab_magazine_t)+SLAB_MAG_SIZE*sizeof(void*),
  640.                sizeof(__address),
  641.                NULL, NULL,
  642.                SLAB_CACHE_NOMAGAZINE);
  643.  
  644.     /* Initialize structures for malloc */
  645. }
  646.