/* $OpenLDAP$ */
/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
*
- * Copyright 2003-2009 The OpenLDAP Foundation.
+ * Copyright 2003-2010 The OpenLDAP Foundation.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
static struct slab_heap *slheap;
#endif
+/* This allocator always returns memory aligned on a 2-int boundary.
+ *
+ * The stack-based allocator stores the size as a ber_len_t at both
+ * the head and tail of the allocated block. When freeing a block, the
+ * tail length is ORed with 1 to mark it as free. Freed space can only
+ * be reclaimed from the tail forward. If the tail block is never freed,
+ * nothing else will be reclaimed until the slab is reset...
+ */
void *
slap_sl_mem_create(
ber_len_t size,
sh = sh_tmp;
#endif
- if ( !new )
+ if ( sh && !new )
return sh;
/* round up to doubleword boundary */
if ( newptr == NULL ) return NULL;
sh->sh_base = newptr;
}
- sh->sh_last = sh->sh_base;
+ /* insert dummy len */
+ {
+ ber_len_t *i = sh->sh_base;
+ *i++ = 0;
+ sh->sh_last = i;
+ }
sh->sh_end = (char *) sh->sh_base + size;
sh->sh_stack = stack;
return sh;
)
{
struct slab_heap *sh = ctx;
- ber_len_t size_shift;
int pad = 2*sizeof(int)-1, pad_shift;
- int order = -1, order_start = -1;
- struct slab_object *so_new, *so_left, *so_right;
ber_len_t *ptr, *newptr;
- unsigned long diff;
- int i, j;
#ifdef SLAP_NO_SL_MALLOC
newptr = ber_memalloc_x( size, NULL );
exit( EXIT_FAILURE );
}
- /* round up to doubleword boundary */
- size += sizeof(ber_len_t) + pad;
+ /* round up to doubleword boundary, plus space for len at head and tail */
+ size += 2*sizeof(ber_len_t) + pad;
size &= ~pad;
if (sh->sh_stack) {
return ch_malloc(size);
}
newptr = sh->sh_last;
- *newptr++ = size - sizeof(ber_len_t);
sh->sh_last = (char *) sh->sh_last + size;
+ size -= sizeof(ber_len_t);
+ *newptr++ = size;
+ *(ber_len_t *)((char *)sh->sh_last - sizeof(ber_len_t)) = size;
return( (void *)newptr );
} else {
+ struct slab_object *so_new, *so_left, *so_right;
+ ber_len_t size_shift;
+ int order = -1, order_start = -1;
+ unsigned long diff;
+ int i, j;
+
size_shift = size - 1;
do {
order++;
size += pad + sizeof( ber_len_t );
size &= ~pad;
+ p--;
+
/* Never shrink blocks */
- if (size <= p[-1]) {
- newptr = p;
+ if (size <= p[0]) {
+ newptr = ptr;
/* If reallocing the last block, we can grow it */
- } else if ((char *)ptr + p[-1] == sh->sh_last &&
+ } else if ((char *)ptr + p[0] == sh->sh_last &&
(char *)ptr + size < (char *)sh->sh_end ) {
- newptr = p;
- sh->sh_last = (char *)sh->sh_last + size - p[-1];
- p[-1] = size;
-
+ newptr = ptr;
+ sh->sh_last = (char *)ptr + size;
+ p[0] = size;
+ p[size/sizeof(ber_len_t)] = size;
+
/* Nowhere to grow, need to alloc and copy */
} else {
- newptr = slap_sl_malloc(size, ctx);
- AC_MEMCPY(newptr, ptr, p[-1]);
+ newptr = slap_sl_malloc(size-sizeof(ber_len_t), ctx);
+ AC_MEMCPY(newptr, ptr, p[0]-sizeof(ber_len_t));
+ /* mark old region as free */
+ p[p[0]/sizeof(ber_len_t)] |= 1;
}
return newptr;
} else {
slap_sl_free(void *ptr, void *ctx)
{
struct slab_heap *sh = ctx;
- int size, size_shift, order_size;
- int pad = 2*sizeof(int)-1, pad_shift;
+ ber_len_t size;
ber_len_t *p = (ber_len_t *)ptr, *tmpp;
- int order_start = -1, order = -1;
- struct slab_object *so;
- unsigned long diff;
- int i, inserted = 0;
if (!ptr)
return;
if (!sh || ptr < sh->sh_base || ptr >= sh->sh_end) {
ber_memfree_x(ptr, NULL);
- } else if (sh->sh_stack && (char *)ptr + p[-1] == sh->sh_last) {
- p--;
- sh->sh_last = p;
- } else if (!sh->sh_stack) {
+ } else if (sh->sh_stack) {
+ tmpp = (ber_len_t *)((char *)ptr + p[-1]);
+ /* mark it free */
+ tmpp[-1] |= 1;
+ /* reclaim free space off tail */
+ while ( tmpp == sh->sh_last ) {
+ if ( tmpp[-1] & 1 ) {
+ size = tmpp[-1] ^ 1;
+ ptr = (char *)tmpp - size;
+ p = (ber_len_t *)ptr;
+ p--;
+ sh->sh_last = p;
+ tmpp = sh->sh_last;
+ } else {
+ break;
+ }
+ }
+ } else {
+ int size_shift, order_size;
+ int pad = 2*sizeof(int)-1, pad_shift;
+ int order_start = -1, order = -1;
+ struct slab_object *so;
+ unsigned long diff;
+ int i, inserted = 0;
+
size = *(--p);
size_shift = size + sizeof(ber_len_t) - 1;
do {