WebSVN – HelenOS-historic – Diff – /kernel/trunk/generic/src/mm/slab.c


/*
 * Copyright (C) 2006 Ondrej Palkovsky
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
/*
 * The SLAB allocator is closely modelled after Opensolaris SLAB allocator
 * http://www.usenix.org/events/usenix01/full_papers/bonwick/bonwick_html/
 *
 * with the following exceptions:
 *   - empty SLABS are deallocated immediately
 *     (in Linux they are kept in linked list, in Solaris ???)
 *   - empty magazines are deallocated when not needed
 *     (in Solaris they are held in linked list in slab cache)
 *
 *   Following features are not currently supported but would be easy to do:
 *   - cache coloring
 *   - dynamic magazine growing (different magazine sizes are already
 *     supported, but we would need to adjust allocating strategy)
 *
 * The SLAB allocator supports per-CPU caches ('magazines') to facilitate
 * good SMP scaling.
 *
 * When a new object is being allocated, it is first checked, if it is
 * available in CPU-bound magazine. If it is not found there, it is
 * allocated from CPU-shared SLAB - if partial full is found, it is used,
 * otherwise a new one is allocated.
 *
 * When an object is being deallocated, it is put to CPU-bound magazine.
 * If there is no such magazine, new one is allocated (if it fails,
 * the object is deallocated into SLAB). If the magazine is full, it is
 * put into cpu-shared list of magazines and new one is allocated.
 *
 * The CPU-bound magazine is actually a pair of magazine to avoid
 * thrashing when somebody is allocating/deallocating 1 item at the magazine
 * size boundary. LIFO order is enforced, which should avoid fragmentation
 * as much as possible.
 *  
 * Every cache contains list of full slabs and list of partialy full slabs.
 * Empty SLABS are immediately freed (thrashing will be avoided because
 * of magazines).
 *
 * The SLAB information structure is kept inside the data area, if possible.
 * The cache can be marked that it should not use magazines. This is used
 * only for SLAB related caches to avoid deadlocks and infinite recursion
 * (the SLAB allocator uses itself for allocating all it's control structures).
 *
 * The SLAB allocator allocates lot of space and does not free it. When
 * frame allocator fails to allocate the frame, it calls slab_reclaim().
 * It tries 'light reclaim' first, then brutal reclaim. The light reclaim
 * releases slabs from cpu-shared magazine-list, until at least 1 slab
 * is deallocated in each cache (this algorithm should probably change).
 * The brutal reclaim removes all cached objects, even from CPU-bound
 * magazines.
 *
 *
 */
 
 
#include <synch/spinlock.h>
#include <mm/slab.h>
#include <list.h>
#include <memstr.h>
#include <align.h>
#include <mm/heap.h>
#include <mm/frame.h>
#include <config.h>
#include <print.h>
#include <arch.h>
#include <panic.h>
#include <debug.h>
#include <bitops.h>
 
SPINLOCK_INITIALIZE(slab_cache_lock);
static LIST_INITIALIZE(slab_cache_list);
 
/** Magazine cache */
static slab_cache_t mag_cache;
/** Cache for cache descriptors */
static slab_cache_t slab_cache_cache;
 
/** Cache for external slab descriptors
 * This time we want per-cpu cache, so do not make it static
 * - using SLAB for internal SLAB structures will not deadlock,
 *   as all slab structures are 'small' - control structures of
 *   their caches do not require further allocation
 */
static slab_cache_t *slab_extern_cache;
/** Caches for malloc */
static slab_cache_t *malloc_caches[SLAB_MAX_MALLOC_W-SLAB_MIN_MALLOC_W+1];
char *malloc_names[] =  {
    "malloc-8","malloc-16","malloc-32","malloc-64","malloc-128",
    "malloc-256","malloc-512","malloc-1K","malloc-2K",
    "malloc-4K","malloc-8K","malloc-16K","malloc-32K",
    "malloc-64K","malloc-128K"
};
 
/** Slab descriptor */
typedef struct {
    slab_cache_t *cache; /**< Pointer to parent cache */
    link_t link;       /* List of full/partial slabs */
    void *start;       /**< Start address of first available item */
    count_t available; /**< Count of available items in this slab */
    index_t nextavail; /**< The index of next available item */
}slab_t;
 
/**************************************/
/* SLAB allocation functions          */
 
/**
 * Allocate frames for slab space and initialize
 *
 */
static slab_t * slab_space_alloc(slab_cache_t *cache, int flags)
{
    void *data;
    slab_t *slab;
    size_t fsize;
    int i;
    zone_t *zone = NULL;
    int status;
    frame_t *frame;
 
    data = (void *)frame_alloc(FRAME_KA | flags, cache->order, &status, &zone);
    if (status != FRAME_OK) {
        return NULL;
    }
    if (! (cache->flags & SLAB_CACHE_SLINSIDE)) {
        slab = slab_alloc(slab_extern_cache, flags);
        if (!slab) {
            frame_free((__address)data);
            return NULL;
        }
    } else {
        fsize = (PAGE_SIZE << cache->order);
        slab = data + fsize - sizeof(*slab);
    }
       
    /* Fill in slab structures */
    /* TODO: some better way of accessing the frame */
    for (i=0; i < (1 << cache->order); i++) {
        frame = ADDR2FRAME(zone, KA2PA((__address)(data+i*PAGE_SIZE)));
        frame->parent = slab;
    }
 
    slab->start = data;
    slab->available = cache->objects;
    slab->nextavail = 0;
    slab->cache = cache;
 
    for (i=0; i<cache->objects;i++)
        *((int *) (slab->start + i*cache->size)) = i+1;
 
    atomic_inc(&cache->allocated_slabs);
    return slab;
}
 
/**
 * Deallocate space associated with SLAB
 *
 * @return number of freed frames
 */
static count_t slab_space_free(slab_cache_t *cache, slab_t *slab)
{
    frame_free((__address)slab->start);
    if (! (cache->flags & SLAB_CACHE_SLINSIDE))
        slab_free(slab_extern_cache, slab);
 
    atomic_dec(&cache->allocated_slabs);
   
    return 1 << cache->order;
}
 
/** Map object to slab structure */
static slab_t * obj2slab(void *obj)
{
    frame_t *frame;
 
    frame = frame_addr2frame((__address)obj);
    return (slab_t *)frame->parent;
}
 
/**************************************/
/* SLAB functions */
 
 
/**
 * Return object to slab and call a destructor
 *
 * Assume the cache->lock is held;
 *
 * @param slab If the caller knows directly slab of the object, otherwise NULL
 *
 * @return Number of freed pages
 */
static count_t slab_obj_destroy(slab_cache_t *cache, void *obj,
                slab_t *slab)
{
    count_t frames = 0;
 
    if (!slab)
        slab = obj2slab(obj);
 
    ASSERT(slab->cache == cache);
 
    *((int *)obj) = slab->nextavail;
    slab->nextavail = (obj - slab->start)/cache->size;
    slab->available++;
 
    /* Move it to correct list */
    if (slab->available == 1) {
        /* It was in full, move to partial */
        list_remove(&slab->link);
        list_prepend(&slab->link, &cache->partial_slabs);
    }
    if (slab->available == cache->objects) {
        /* Free associated memory */
        list_remove(&slab->link);
        /* Avoid deadlock */
        spinlock_unlock(&cache->lock);
        frames = slab_space_free(cache, slab);
        spinlock_lock(&cache->lock);
    }
 
    return frames;
}
 
/**
 * Take new object from slab or create new if needed
 *
 * Assume cache->lock is held.
 *
 * @return Object address or null
 */
static void * slab_obj_create(slab_cache_t *cache, int flags)
{
    slab_t *slab;
    void *obj;
 
    if (list_empty(&cache->partial_slabs)) {
        /* Allow recursion and reclaiming
         * - this should work, as the SLAB control structures
         *   are small and do not need to allocte with anything
         *   other ten frame_alloc when they are allocating,
         *   that's why we should get recursion at most 1-level deep
         */
        spinlock_unlock(&cache->lock);
        slab = slab_space_alloc(cache, flags);
        spinlock_lock(&cache->lock);
        if (!slab) {
            return NULL;
        }
    } else {
        slab = list_get_instance(cache->partial_slabs.next,
                     slab_t,
                     link);
        list_remove(&slab->link);
    }
    obj = slab->start + slab->nextavail * cache->size;
    slab->nextavail = *((int *)obj);
    slab->available--;
    if (! slab->available)
        list_prepend(&slab->link, &cache->full_slabs);
    else
        list_prepend(&slab->link, &cache->partial_slabs);
    return obj;
}
 
/**************************************/
/* CPU-Cache slab functions */
 
/**
 * Free all objects in magazine and free memory associated with magazine
 *
 * Assume mag_cache[cpu].lock is locked
 *
 * @return Number of freed pages
 */
static count_t magazine_destroy(slab_cache_t *cache,
                slab_magazine_t *mag)
{
    int i;
    count_t frames = 0;
 
    for (i=0;i < mag->busy; i++) {
        frames += slab_obj_destroy(cache, mag->objs[i], NULL);
        atomic_dec(&cache->cached_objs);
    }
   
    slab_free(&mag_cache, mag);
 
    return frames;
}
 
/**
 * Find full magazine, set it as current and return it
 *
 * Assume cpu_magazine lock is held
 */
static slab_magazine_t * get_full_current_mag(slab_cache_t *cache)
{
    slab_magazine_t *cmag, *lastmag, *newmag;
 
    cmag = cache->mag_cache[CPU->id].current;
    lastmag = cache->mag_cache[CPU->id].last;
    if (cmag) { /* First try local CPU magazines */
        if (cmag->busy)
            return cmag;
 
        if (lastmag && lastmag->busy) {
            cache->mag_cache[CPU->id].current = lastmag;
            cache->mag_cache[CPU->id].last = cmag;
            return lastmag;
        }
    }
    /* Local magazines are empty, import one from magazine list */
    spinlock_lock(&cache->lock);
    if (list_empty(&cache->magazines)) {
        spinlock_unlock(&cache->lock);
        return NULL;
    }
    newmag = list_get_instance(cache->magazines.next,
                   slab_magazine_t,
                   link);
    list_remove(&newmag->link);
    spinlock_unlock(&cache->lock);
 
    if (lastmag)
        slab_free(&mag_cache, lastmag);
    cache->mag_cache[CPU->id].last = cmag;
    cache->mag_cache[CPU->id].current = newmag;
    return newmag;
}
 
/**
 * Try to find object in CPU-cache magazines
 *
 * @return Pointer to object or NULL if not available
 */
static void * magazine_obj_get(slab_cache_t *cache)
{
    slab_magazine_t *mag;
    void *obj;
 
    spinlock_lock(&cache->mag_cache[CPU->id].lock);
 
    mag = get_full_current_mag(cache);
    if (!mag) {
        spinlock_unlock(&cache->mag_cache[CPU->id].lock);
        return NULL;
    }
    obj = mag->objs[--mag->busy];
    spinlock_unlock(&cache->mag_cache[CPU->id].lock);
    atomic_dec(&cache->cached_objs);
   
    return obj;
}
 
/**
 * Assure that the current magazine is empty, return pointer to it, or NULL if
 * no empty magazine is available and cannot be allocated
 *
 * We have 2 magazines bound to processor.
 * First try the current.
 *  If full, try the last.
 *   If full, put to magazines list.
 *   allocate new, exchange last & current
 *
 */
static slab_magazine_t * make_empty_current_mag(slab_cache_t *cache)
{
    slab_magazine_t *cmag,*lastmag,*newmag;
 
    cmag = cache->mag_cache[CPU->id].current;
    lastmag = cache->mag_cache[CPU->id].last;
 
    if (cmag) {
        if (cmag->busy < cmag->size)
            return cmag;
        if (lastmag && lastmag->busy < lastmag->size) {
            cache->mag_cache[CPU->id].last = cmag;
            cache->mag_cache[CPU->id].current = lastmag;
            return lastmag;
        }
    }
    /* current | last are full | nonexistent, allocate new */
    /* We do not want to sleep just because of caching */
    /* Especially we do not want reclaiming to start, as
     * this would deadlock */
    newmag = slab_alloc(&mag_cache, FRAME_ATOMIC | FRAME_NO_RECLAIM);
    if (!newmag)
        return NULL;
    newmag->size = SLAB_MAG_SIZE;
    newmag->busy = 0;
 
    /* Flush last to magazine list */
    if (lastmag)
        list_prepend(&lastmag->link, &cache->magazines);
    /* Move current as last, save new as current */
    cache->mag_cache[CPU->id].last = cmag; 
    cache->mag_cache[CPU->id].current = newmag;
 
    return newmag;
}
 
/**
 * Put object into CPU-cache magazine
 *
 * @return 0 - success, -1 - could not get memory
 */
static int magazine_obj_put(slab_cache_t *cache, void *obj)
{
    slab_magazine_t *mag;
 
    spinlock_lock(&cache->mag_cache[CPU->id].lock);
 
    mag = make_empty_current_mag(cache);
    if (!mag) {
        spinlock_unlock(&cache->mag_cache[CPU->id].lock);
        return -1;
    }
   
    mag->objs[mag->busy++] = obj;
 
    spinlock_unlock(&cache->mag_cache[CPU->id].lock);
    atomic_inc(&cache->cached_objs);
    return 0;
}
 
 
/**************************************/
/* SLAB CACHE functions */
 
/** Return number of objects that fit in certain cache size */
static int comp_objects(slab_cache_t *cache)
{
    if (cache->flags & SLAB_CACHE_SLINSIDE)
        return ((PAGE_SIZE << cache->order) - sizeof(slab_t)) / cache->size;
    else
        return (PAGE_SIZE << cache->order) / cache->size;
}
 
/** Return wasted space in slab */
static int badness(slab_cache_t *cache)
{
    int objects;
    int ssize;
 
    objects = comp_objects(cache);
    ssize = PAGE_SIZE << cache->order;
    if (cache->flags & SLAB_CACHE_SLINSIDE)
        ssize -= sizeof(slab_t);
    return ssize - objects*cache->size;
}
 
/** Initialize allocated memory as a slab cache */
static void
_slab_cache_create(slab_cache_t *cache,
           char *name,
           size_t size,
           size_t align,
           int (*constructor)(void *obj, int kmflag),
           void (*destructor)(void *obj),
           int flags)
{
    int i;
    int pages;
 
    memsetb((__address)cache, sizeof(*cache), 0);
    cache->name = name;
 
    if (align < sizeof(__native))
        align = sizeof(__native);
    size = ALIGN_UP(size, align);
       
    cache->size = size;
 
    cache->constructor = constructor;
    cache->destructor = destructor;
    cache->flags = flags;
 
    list_initialize(&cache->full_slabs);
    list_initialize(&cache->partial_slabs);
    list_initialize(&cache->magazines);
    spinlock_initialize(&cache->lock, "cachelock");
    if (! (cache->flags & SLAB_CACHE_NOMAGAZINE)) {
        for (i=0; i< config.cpu_count; i++)
            spinlock_initialize(&cache->mag_cache[i].lock,
                        "cpucachelock");
    }
 
    /* Compute slab sizes, object counts in slabs etc. */
    if (cache->size < SLAB_INSIDE_SIZE)
        cache->flags |= SLAB_CACHE_SLINSIDE;
 
    /* Minimum slab order */
    pages = ((cache->size-1) >> PAGE_WIDTH) + 1;
    cache->order = fnzb(pages);
 
    while (badness(cache) > SLAB_MAX_BADNESS(cache)) {
        cache->order += 1;
    }
    cache->objects = comp_objects(cache);
    /* If info fits in, put it inside */
    if (badness(cache) > sizeof(slab_t))
        cache->flags |= SLAB_CACHE_SLINSIDE;
 
    spinlock_lock(&slab_cache_lock);
 
    list_append(&cache->link, &slab_cache_list);
 
    spinlock_unlock(&slab_cache_lock);
}
 
/** Create slab cache  */
slab_cache_t * slab_cache_create(char *name,
                 size_t size,
                 size_t align,
                 int (*constructor)(void *obj, int kmflag),
                 void (*destructor)(void *obj),
                 int flags)
{
    slab_cache_t *cache;
 
    cache = slab_alloc(&slab_cache_cache, 0);
    _slab_cache_create(cache, name, size, align, constructor, destructor,
               flags);
    return cache;
}
 
/**
 * Reclaim space occupied by objects that are already free
 *
 * @param flags If contains SLAB_RECLAIM_ALL, do aggressive freeing
 * @return Number of freed pages
 */
static count_t _slab_reclaim(slab_cache_t *cache, int flags)
{
    int i;
    slab_magazine_t *mag;
    link_t *cur;
    count_t frames = 0;
   
    if (cache->flags & SLAB_CACHE_NOMAGAZINE)
        return 0; /* Nothing to do */
   
    /* First lock all cpu caches, then the complete cache lock */
    if (flags & SLAB_RECLAIM_ALL) {
        for (i=0; i < config.cpu_count; i++)
            spinlock_lock(&cache->mag_cache[i].lock);
    }
    spinlock_lock(&cache->lock);
   
    if (flags & SLAB_RECLAIM_ALL) {
        /* Aggressive memfree */
        /* Destroy CPU magazines */
        for (i=0; i<config.cpu_count; i++) {
            mag = cache->mag_cache[i].current;
            if (mag)
                frames += magazine_destroy(cache, mag);
            cache->mag_cache[i].current = NULL;
           
            mag = cache->mag_cache[i].last;
            if (mag)
                frames += magazine_destroy(cache, mag);
            cache->mag_cache[i].last = NULL;
        }
    }
    /* Destroy full magazines */
    cur=cache->magazines.prev;
 
    while (cur != &cache->magazines) {
        mag = list_get_instance(cur, slab_magazine_t, link);
       
        cur = cur->prev;
        list_remove(&mag->link);
        frames += magazine_destroy(cache,mag);
        /* If we do not do full reclaim, break
         * as soon as something is freed */
        if (!(flags & SLAB_RECLAIM_ALL) && frames)
            break;
    }
   
    spinlock_unlock(&cache->lock);
    if (flags & SLAB_RECLAIM_ALL) {
        for (i=0; i < config.cpu_count; i++)
            spinlock_unlock(&cache->mag_cache[i].lock);
    }
   
    return frames;
}
 
/** Check that there are no slabs and remove cache from system  */
void slab_cache_destroy(slab_cache_t *cache)
{
    /* Do not lock anything, we assume the software is correct and
     * does not touch the cache when it decides to destroy it */
   
    /* Destroy all magazines */
    _slab_reclaim(cache, SLAB_RECLAIM_ALL);
 
    /* All slabs must be empty */
    if (!list_empty(&cache->full_slabs) \
        || !list_empty(&cache->partial_slabs))
        panic("Destroying cache that is not empty.");
 
    spinlock_lock(&slab_cache_lock);
    list_remove(&cache->link);
    spinlock_unlock(&slab_cache_lock);
 
    slab_free(&slab_cache_cache, cache);
}
 
/** Allocate new object from cache - if no flags given, always returns
    memory */
void * slab_alloc(slab_cache_t *cache, int flags)
{
    ipl_t ipl;
    void *result = NULL;
 
    /* Disable interrupts to avoid deadlocks with interrupt handlers */
    ipl = interrupts_disable();
 
    if (!(cache->flags & SLAB_CACHE_NOMAGAZINE) && CPU)
        result = magazine_obj_get(cache);
 
    if (!result) {
        spinlock_lock(&cache->lock);
        result = slab_obj_create(cache, flags);
        spinlock_unlock(&cache->lock);
    }
 
    interrupts_restore(ipl);
 
    if (result)
        atomic_inc(&cache->allocated_objs);
 
    return result;
}
 
/** Return object to cache, use slab if known  */
static void _slab_free(slab_cache_t *cache, void *obj, slab_t *slab)
{
    ipl_t ipl;
 
    ipl = interrupts_disable();
 
    if ((cache->flags & SLAB_CACHE_NOMAGAZINE) \
        || !CPU \
        || magazine_obj_put(cache, obj)) {
       
        spinlock_lock(&cache->lock);
        slab_obj_destroy(cache, obj, slab);
        spinlock_unlock(&cache->lock);
    }
    interrupts_restore(ipl);
    atomic_dec(&cache->allocated_objs);
}
 
/** Return slab object to cache */
void slab_free(slab_cache_t *cache, void *obj)
{
    _slab_free(cache,obj,NULL);
}
 
/* Go through all caches and reclaim what is possible */
count_t slab_reclaim(int flags)
{
    slab_cache_t *cache;
    link_t *cur;
    count_t frames = 0;
 
    spinlock_lock(&slab_cache_lock);
 
    for (cur = slab_cache_list.next;cur!=&slab_cache_list; cur=cur->next) {
        cache = list_get_instance(cur, slab_cache_t, link);
        frames += _slab_reclaim(cache, flags);
    }
 
    spinlock_unlock(&slab_cache_lock);
 
    return frames;
}
 
 
/* Print list of slabs */
void slab_print_list(void)
{
    slab_cache_t *cache;
    link_t *cur;
 
    spinlock_lock(&slab_cache_lock);
    printf("SLAB name\tOsize\tPages\tObj/pg\tSlabs\tCached\tAllocobjs\tCtl\n");
    for (cur = slab_cache_list.next;cur!=&slab_cache_list; cur=cur->next) {
        cache = list_get_instance(cur, slab_cache_t, link);
        printf("%s\t%d\t%d\t%d\t%d\t%d\t%d\t\t%s\n", cache->name, cache->size,
               (1 << cache->order), cache->objects,
               atomic_get(&cache->allocated_slabs),
               atomic_get(&cache->cached_objs),
               atomic_get(&cache->allocated_objs),
               cache->flags & SLAB_CACHE_SLINSIDE ? "In" : "Out");
    }
    spinlock_unlock(&slab_cache_lock);
}
 
void slab_cache_init(void)
{
    int i, size;
 
    /* Initialize magazine cache */
    _slab_cache_create(&mag_cache,
               "slab_magazine",
               sizeof(slab_magazine_t)+SLAB_MAG_SIZE*sizeof(void*),
               sizeof(__address),
               NULL, NULL,
               SLAB_CACHE_NOMAGAZINE | SLAB_CACHE_SLINSIDE);
    /* Initialize slab_cache cache */
    _slab_cache_create(&slab_cache_cache,
               "slab_cache",
               sizeof(slab_cache_cache) + config.cpu_count*sizeof(slab_cache_cache.mag_cache[0]),
               sizeof(__address),
               NULL, NULL,
               SLAB_CACHE_NOMAGAZINE | SLAB_CACHE_SLINSIDE);
    /* Initialize external slab cache */
    slab_extern_cache = slab_cache_create("slab_extern",
                          sizeof(slab_t),
                          0, NULL, NULL,
                          SLAB_CACHE_SLINSIDE);
 
    /* Initialize structures for malloc */
    for (i=0, size=(1<<SLAB_MIN_MALLOC_W);
         i < (SLAB_MAX_MALLOC_W-SLAB_MIN_MALLOC_W+1);
         i++, size <<= 1) {
        malloc_caches[i] = slab_cache_create(malloc_names[i],
                             size, 0,
                             NULL,NULL,0);
    }
}
 
/**************************************/
/* kalloc/kfree functions             */
void * kalloc(unsigned int size, int flags)
{
    int idx;
 
    ASSERT( size && size <= (1 << SLAB_MAX_MALLOC_W));
   
    if (size < (1 << SLAB_MIN_MALLOC_W))
        size = (1 << SLAB_MIN_MALLOC_W);
 
    idx = fnzb(size-1) - SLAB_MIN_MALLOC_W + 1;
 
    return slab_alloc(malloc_caches[idx], flags);
}
 
 
void kfree(void *obj)
{
    slab_t *slab = obj2slab(obj);
   
    _slab_free(slab->cache, obj, slab);
}
 
Subversion Repositories HelenOS-historic

(root)/kernel/trunk/generic/src/mm/slab.c – Rev 769 → 771
