void* slab_alloc(slab_t* slab)
{
// Fetch first free item
void **item = 0;
{
if((item = slab->head)) {
slab->head = (void**)*item;
--slab->bufs_free;
} else {
// No more free items
return 0;
}
}
#ifdef MEM_DEBUG
// Increment statistics
__sync_add_and_fetch(&slab->cache->stat_allocs, 1);
#endif
// Move to full?
if (knot_unlikely(slab->bufs_free == 0)) {
slab_list_move(&slab->cache->slabs_full, slab);
} else {
#ifdef MEM_SLAB_CAP
// Mark not empty?
if (knot_unlikely(slab->bufs_free == slab->bufs_count - 1)) {
--slab->cache->empty;
}
#endif
}
return item;
}
void slab_free(void* ptr)
{
// Null pointer check
if (knot_unlikely(!ptr)) {
return;
}
// Get slab start address
slab_t* slab = slab_from_ptr(ptr);
assert(slab);
// Check if it exists in directory
if (slab->magic == SLAB_MAGIC) {
// Return buf to slab
*((void**)ptr) = (void*)slab->head;
slab->head = (void**)ptr;
++slab->bufs_free;
#ifdef MEM_DEBUG
// Increment statistics
__sync_add_and_fetch(&slab->cache->stat_frees, 1);
#endif
// Return to partial
if(knot_unlikely(slab->bufs_free == 1)) {
slab_list_move(&slab->cache->slabs_free, slab);
} else {
#ifdef MEM_SLAB_CAP
// Recycle if empty
if(knot_unlikely(slab_isempty(slab))) {
if(slab->cache->empty == MEM_SLAB_CAP) {
slab_destroy(&slab);
} else {
++slab->cache->empty;
}
}
#endif
}
} else {
// Pointer is not a slab
// Presuming it's a large block
slab_obj_t* bs = (slab_obj_t*)ptr - 1;
#ifdef MEM_POISON
// Remove memory barrier
mprotect(ptr + bs->size, sizeof(int), PROT_READ|PROT_WRITE);
#endif
// Unmap
dbg_mem("%s: unmapping large block of %zu bytes at %p\n",
__func__, bs->size, ptr);
free(bs);
}
}
uint8_t log_levels(int facility, logsrc_t src)
{
// Check facility
if (knot_unlikely(!LOG_FCL_SIZE || facility >= LOG_FCL_SIZE)) {
return 0;
}
return *(LOG_FCL + (facility << LOG_SRC_BITS) + src);
}
int slab_cache_init(slab_cache_t* cache, size_t bufsize)
{
if (knot_unlikely(!bufsize)) {
return -1;
}
memset(cache, 0, sizeof(slab_cache_t));
cache->bufsize = bufsize;
dbg_mem("%s: created cache of size %zu\n",
__func__, bufsize);
return 0;
}
int log_open_file(const char* filename)
{
// Check facility
if (knot_unlikely(!LOG_FCL_SIZE || LOGT_FILE + LOG_FDS_OPEN >= LOG_FCL_SIZE)) {
return KNOT_ERROR;
}
// Open file
LOG_FDS[LOG_FDS_OPEN] = fopen(filename, "a");
if (!LOG_FDS[LOG_FDS_OPEN]) {
return KNOT_EINVAL;
}
// Disable buffering
setvbuf(LOG_FDS[LOG_FDS_OPEN], (char *)0, _IONBF, 0);
return LOGT_FILE + LOG_FDS_OPEN++;
}
int log_levels_set(int facility, logsrc_t src, uint8_t levels)
{
// Check facility
if (knot_unlikely(!LOG_FCL_SIZE || facility >= LOG_FCL_SIZE)) {
return KNOT_EINVAL;
}
// Get facility pointer from offset
uint8_t *lp = LOG_FCL + (facility << LOG_SRC_BITS);
// Assign level if not multimask
if (src != LOG_ANY) {
*(lp + src) = levels;
} else {
// Any == set to all sources
for (int i = 0; i <= LOG_ANY; ++i) {
*(lp + i) = levels;
}
}
return KNOT_EOK;
}
slab_t* slab_create(slab_cache_t* cache)
{
const size_t size = SLAB_SZ;
slab_t* slab = slab_depot_alloc(cache->bufsize);
if (knot_unlikely(slab == 0)) {
dbg_mem("%s: failed to allocate aligned memory block\n",
__func__);
return 0;
}
/* Initialize slab. */
slab->magic = SLAB_MAGIC;
slab->cache = cache;
slab_list_insert(&cache->slabs_free, slab);
#ifdef MEM_SLAB_CAP
++cache->empty;
#endif
/* Already initialized? */
if (slab->bufsize == cache->bufsize) {
return slab;
} else {
slab->bufsize = cache->bufsize;
}
/* Ensure the item size can hold at least a size of ptr. */
size_t item_size = slab->bufsize;
if (knot_unlikely(item_size < SLAB_MIN_BUFLEN)) {
item_size = SLAB_MIN_BUFLEN;
}
/* Ensure at least some space for coloring */
size_t data_size = size - sizeof(slab_t);
#ifdef MEM_COLORING
size_t free_space = data_size % item_size;
if (knot_unlikely(free_space < SLAB_MINCOLOR)) {
free_space = SLAB_MINCOLOR;
}
/// unsigned short color = __sync_fetch_and_add(&cache->color, 1);
unsigned short color = (cache->color += sizeof(void*));
color = color % free_space;
#else
const unsigned short color = 0;
#endif
/* Calculate useable data size */
data_size -= color;
slab->bufs_count = data_size / item_size;
slab->bufs_free = slab->bufs_count;
// Save first item as next free
slab->base = (char*)slab + sizeof(slab_t) + color;
slab->head = (void**)slab->base;
// Create freelist, skip last member, which is set to NULL
char* item = (char*)slab->head;
for(unsigned i = 0; i < slab->bufs_count - 1; ++i) {
*((void**)item) = item + item_size;
item += item_size;
}
// Set last buf to NULL (tail)
*((void**)item) = (void*)0;
// Ensure the last item has a NULL next
dbg_mem("%s: created slab (%p, %p) (%zu B)\n",
__func__, slab, slab + size, size);
return slab;
}
