/* add buffer (chunk) of specific size to cache
*/
static struct chunk*
dscache_alloc( struct dscache* cache, size_t chunklen )
{
struct chunk *chnk = freelist_alloc( cache, chunklen );
if( !chnk )
chnk = heap_alloc( cache, chunklen );
if( !chnk ) {
LTRACE( (void)tmfprintf( g_flog,
"%s: cannot allocate chunk", __func__ ) );
return NULL;
}
chnk->next = NULL;
if( NULL == cache->head )
cache->head = chnk;
if( NULL != cache->tail )
cache->tail->next = chnk;
cache->tail = chnk;
return chnk;
}
void *freelist_alloc( size_t length )
{
char buf[20];
pmeta walker = NULL;
pmeta newone = NULL;
/// If there isn't a block on the free list then initialize one
/// This should only be the case on the first allocation request
if ( lookaside[0] == NULL ) {
init_freelist();
}
walker = (pmeta)lookaside[0];
// Walk while looking for the smallest useable
while ( walker ) {
if ( walker->length < length ) {
walker = walker->next;
} else {
break;
}
}
if ( walker == NULL ) {
//printf("no blocks found\n");
add_freelist_block( length );
return freelist_alloc(length);
} else {
//printf("foudn block size: $d\n", walker->length );
unlink(walker);
/// If the block is less than the size needed for at
/// least an 8 byte block then return the whole thing
/// That means sizeof(meta) prev and next total 8 bytes
/// bytes on the lookaside list
if ( walker->length - length < sizeof(meta) ) {
/// Skip the 4 byte length
return ((char*)walker) + 4;
}
/// Break the chunk off
newone = (pmeta) ( ((char*)walker) + 4 + length );
newone->length = walker->length - (length+4);
//printf("Broke $d into $d and $d\n", walker->length, length, newone->length);
walker->length = length;
link(newone);
//printf("Returning size: $d\n", walker->length);
return ((char*)walker) + 4;
}
return NULL;
}
void *malloc( size_t length )
{
int bucket = 0;
pmeta outb = NULL;
// The minimum size for a valid request is 8 bytes
if ( length < 8 ) {
length = 8;
}
// Round up to nearest 8
length = (length+7) & 0xfffffff8;
bucket = BUCKET(length);
if ( bucket == 0 ) {
outb = freelist_alloc(length);
return outb;
} else {
while ( bucket < 128 ) {
if ( lookaside[ bucket] != NULL ) {
break;
}
bucket++;
}
}
if ( bucket == 128 ) {
//printf("No available buckets freelist alloc\n");
return freelist_alloc( length );
} else {
//printf("Found bucket: $d\n", bucket);
outb = lookaside[ bucket ];
lookaside[bucket] = outb->next;
return ( (char*)outb ) + 4;
}
return NULL;
}
