/* $NetBSD: sl_malloc.c,v 1.1.1.6.6.1 2019/08/10 06:17:17 martin Exp $ */
/* sl_malloc.c - malloc routines using a per-thread slab */
/* $OpenLDAP$ */
/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
*
* Copyright 2003-2019 The OpenLDAP Foundation.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted only as authorized by the OpenLDAP
* Public License.
*
* A copy of this license is available in the file LICENSE in the
* top-level directory of the distribution or, alternatively, at
* <http://www.OpenLDAP.org/license.html>.
*/
#include <sys/cdefs.h>
__RCSID("$NetBSD: sl_malloc.c,v 1.1.1.6.6.1 2019/08/10 06:17:17 martin Exp $");
#include "portable.h"
#include <stdio.h>
#include <ac/string.h>
#include "slap.h"
#ifdef USE_VALGRIND
/* Get debugging help from Valgrind */
#include <valgrind/memcheck.h>
#define VGMEMP_MARK(m,s) VALGRIND_MAKE_MEM_NOACCESS(m,s)
#define VGMEMP_CREATE(h,r,z) VALGRIND_CREATE_MEMPOOL(h,r,z)
#define VGMEMP_TRIM(h,a,s) VALGRIND_MEMPOOL_TRIM(h,a,s)
#define VGMEMP_ALLOC(h,a,s) VALGRIND_MEMPOOL_ALLOC(h,a,s)
#define VGMEMP_CHANGE(h,a,b,s) VALGRIND_MEMPOOL_CHANGE(h,a,b,s)
#else
#define VGMEMP_MARK(m,s)
#define VGMEMP_CREATE(h,r,z)
#define VGMEMP_TRIM(h,a,s)
#define VGMEMP_ALLOC(h,a,s)
#define VGMEMP_CHANGE(h,a,b,s)
#endif
/*
* This allocator returns temporary memory from a slab in a given memory
* context, aligned on a 2-int boundary. It cannot be used for data
* which will outlive the task allocating it.
*
* A new memory context attaches to the creator's thread context, if any.
* Threads cannot use other threads' memory contexts; there are no locks.
*
* The caller of slap_sl_malloc, usually a thread pool task, must
* slap_sl_free the memory before finishing: New tasks reuse the context
* and normally reset it, reclaiming memory left over from last task.
*
* The allocator helps memory fragmentation, speed and memory leaks.
* It is not (yet) reliable as a garbage collector:
*
* It falls back to context NULL - plain ber_memalloc() - when the
* context's slab is full. A reset does not reclaim such memory.
* Conversely, free/realloc of data not from the given context assumes
* context NULL. The data must not belong to another memory context.
*
* Code which has lost track of the current memory context can try
* slap_sl_context() or ch_malloc.c:ch_free/ch_realloc().
*
* Allocations cannot yet return failure. Like ch_malloc, they succeed
* or abort slapd. This will change, do fix code which assumes success.
*/
/*
* The stack-based allocator stores (ber_len_t)sizeof(head+block) at
* allocated blocks' head - and in freed blocks also at the tail, marked
* by ORing *next* block's head with 1. Freed blocks are only reclaimed
* from the last block forward. This is fast, but when a block is never
* freed, older blocks will not be reclaimed until the slab is reset...
*/
#ifdef SLAP_NO_SL_MALLOC /* Useful with memory debuggers like Valgrind */
enum { No_sl_malloc = 1 };
#else
enum { No_sl_malloc = 0 };
#endif
#define SLAP_SLAB_SOBLOCK 64
struct slab_object {
void *so_ptr;
int so_blockhead;
LDAP_LIST_ENTRY(slab_object) so_link;
};
struct slab_heap {
void *sh_base;
void *sh_last;
void *sh_end;
int sh_stack;
int sh_maxorder;
unsigned char **sh_map;
LDAP_LIST_HEAD(sh_freelist, slab_object) *sh_free;
LDAP_LIST_HEAD(sh_so, slab_object) sh_sopool;
};
enum {
Align = sizeof(ber_len_t) > 2*sizeof(int)
? sizeof(ber_len_t) : 2*sizeof(int),
Align_log2 = 1 + (Align>2) + (Align>4) + (Align>8) + (Align>16),
order_start = Align_log2 - 1,
pad = Align - 1
};
static struct slab_object * slap_replenish_sopool(struct slab_heap* sh);
#ifdef SLAPD_UNUSED
static void print_slheap(int level, void *ctx);
#endif
/* Keep memory context in a thread-local var, or in a global when no threads */
#ifdef NO_THREADS
static struct slab_heap *slheap;
# define SET_MEMCTX(thrctx, memctx, sfree) ((void) (slheap = (memctx)))
# define GET_MEMCTX(thrctx, memctxp) (*(memctxp) = slheap)
#else
# define memctx_key ((void *) slap_sl_mem_init)
# define SET_MEMCTX(thrctx, memctx, kfree) \
ldap_pvt_thread_pool_setkey(thrctx,memctx_key, memctx,kfree, NULL,NULL)
# define GET_MEMCTX(thrctx, memctxp) \
((void) (*(memctxp) = NULL), \
(void) ldap_pvt_thread_pool_getkey(thrctx,memctx_key, memctxp,NULL), \
*(memctxp))
#endif /* NO_THREADS */
/* Destroy the context, or if key==NULL clean it up for reuse. */
void
slap_sl_mem_destroy(
void *key,
void *data
)
{
struct slab_heap *sh = data;
struct slab_object *so;
int i;
if (!sh->sh_stack) {
for (i = 0; i <= sh->sh_maxorder - order_start; i++) {
so = LDAP_LIST_FIRST(&sh->sh_free[i]);
while (so) {
struct slab_object *so_tmp = so;
so = LDAP_LIST_NEXT(so, so_link);
LDAP_LIST_INSERT_HEAD(&sh->sh_sopool, so_tmp, so_link);
}
ch_free(sh->sh_map[i]);
}
ch_free(sh->sh_free);
ch_free(sh->sh_map);
so = LDAP_LIST_FIRST(&sh->sh_sopool);
while (so) {
struct slab_object *so_tmp = so;
so = LDAP_LIST_NEXT(so, so_link);
if (!so_tmp->so_blockhead) {
LDAP_LIST_REMOVE(so_tmp, so_link);
}
}
so = LDAP_LIST_FIRST(&sh->sh_sopool);
while (so) {
struct slab_object *so_tmp = so;
so = LDAP_LIST_NEXT(so, so_link);
ch_free(so_tmp);
}
}
if (key != NULL) {
ber_memfree_x(sh->sh_base, NULL);
ber_memfree_x(sh, NULL);
}
}
BerMemoryFunctions slap_sl_mfuncs =
{ slap_sl_malloc, slap_sl_calloc, slap_sl_realloc, slap_sl_free };
void
slap_sl_mem_init()
{
assert( Align == 1 << Align_log2 );
ber_set_option( NULL, LBER_OPT_MEMORY_FNS, &slap_sl_mfuncs );
}
/* Create, reset or just return the memory context of the current thread. */
void *
slap_sl_mem_create(
ber_len_t size,
int stack,
void *thrctx,
int new
)
{
void *memctx;
struct slab_heap *sh;
ber_len_t size_shift;
struct slab_object *so;
char *base, *newptr;
enum { Base_offset = (unsigned) -sizeof(ber_len_t) % Align };
sh = GET_MEMCTX(thrctx, &memctx);
if ( sh && !new )
return sh;
/* Round up to doubleword boundary, then make room for initial
* padding, preserving expected available size for pool version */
size = ((size + Align-1) & -Align) + Base_offset;
if (!sh) {
sh = ch_malloc(sizeof(struct slab_heap));
base = ch_malloc(size);
SET_MEMCTX(thrctx, sh, slap_sl_mem_destroy);
VGMEMP_MARK(base, size);
VGMEMP_CREATE(sh, 0, 0);
} else {
slap_sl_mem_destroy(NULL, sh);
base = sh->sh_base;
if (size > (ber_len_t) ((char *) sh->sh_end - base)) {
newptr = ch_realloc(base, size);
if ( newptr == NULL ) return NULL;
VGMEMP_CHANGE(sh, base, newptr, size);
base = newptr;
}
VGMEMP_TRIM(sh, base, 0);
}
sh->sh_base = base;
sh->sh_end = base + size;
/* Align (base + head of first block) == first returned block */
base += Base_offset;
size -= Base_offset;
sh->sh_stack = stack;
if (stack) {
sh->sh_last = base;
} else {
int i, order = -1, order_end = -1;
size_shift = size - 1;
do {
order_end++;
} while (size_shift >>= 1);
order = order_end - order_start + 1;
sh->sh_maxorder = order_end;
sh->sh_free = (struct sh_freelist *)
ch_malloc(order * sizeof(struct sh_freelist));
for (i = 0; i < order; i++) {
LDAP_LIST_INIT(&sh->sh_free[i]);
}
LDAP_LIST_INIT(&sh->sh_sopool);
if (LDAP_LIST_EMPTY(&sh->sh_sopool)) {
slap_replenish_sopool(sh);
}
so = LDAP_LIST_FIRST(&sh->sh_sopool);
LDAP_LIST_REMOVE(so, so_link);
so->so_ptr = base;
LDAP_LIST_INSERT_HEAD(&sh->sh_free[order-1], so, so_link);
sh->sh_map = (unsigned char **)
ch_malloc(order * sizeof(unsigned char *));
for (i = 0; i < order; i++) {
int shiftamt = order_start + 1 + i;
int nummaps = size >> shiftamt;
assert(nummaps);
nummaps >>= 3;
if (!nummaps) nummaps = 1;
sh->sh_map[i] = (unsigned char *) ch_malloc(nummaps);
memset(sh->sh_map[i], 0, nummaps);
}
}
return sh;
}
/*
* Assign memory context to thread context. Use NULL to detach
* current memory context from thread. Future users must
* know the context, since ch_free/slap_sl_context() cannot find it.
*/
void
slap_sl_mem_setctx(
void *thrctx,
void *memctx
)
{
SET_MEMCTX(thrctx, memctx, slap_sl_mem_destroy);
}
void *
slap_sl_malloc(
ber_len_t size,
void *ctx
)
{
struct slab_heap *sh = ctx;
ber_len_t *ptr, *newptr;
/* ber_set_option calls us like this */
if (No_sl_malloc || !ctx) {
newptr = ber_memalloc_x( size, NULL );
if ( newptr ) return newptr;
Debug(LDAP_DEBUG_ANY, "slap_sl_malloc of %lu bytes failed\n",
(unsigned long) size, 0, 0);
assert( 0 );
exit( EXIT_FAILURE );
}
/* Add room for head, ensure room for tail when freed, and
* round up to doubleword boundary. */
size = (size + sizeof(ber_len_t) + Align-1 + !size) & -Align;
if (sh->sh_stack) {
if (size < (ber_len_t) ((char *) sh->sh_end - (char *) sh->sh_last)) {
newptr = sh->sh_last;
sh->sh_last = (char *) sh->sh_last + size;
VGMEMP_ALLOC(sh, newptr, size);
*newptr++ = size;
return( (void *)newptr );
}
size -= sizeof(ber_len_t);
} else {
struct slab_object *so_new, *so_left, *so_right;
ber_len_t size_shift;
unsigned long diff;
int i, j, order = -1;
size_shift = size - 1;
do {
order++;
} while (size_shift >>= 1);
size -= sizeof(ber_len_t);
for (i = order; i <= sh->sh_maxorder &&
LDAP_LIST_EMPTY(&sh->sh_free[i-order_start]); i++);
if (i == order) {
so_new = LDAP_LIST_FIRST(&sh->sh_free[i-order_start]);
LDAP_LIST_REMOVE(so_new, so_link);
ptr = so_new->so_ptr;
diff = (unsigned long)((char*)ptr -
(char*)sh->sh_base) >> (order + 1);
sh->sh_map[order-order_start][diff>>3] |= (1 << (diff & 0x7));
*ptr++ = size;
LDAP_LIST_INSERT_HEAD(&sh->sh_sopool, so_new, so_link);
return((void*)ptr);
} else if (i <= sh->sh_maxorder) {
for (j = i; j > order; j--) {
so_left = LDAP_LIST_FIRST(&sh->sh_free[j-order_start]);
LDAP_LIST_REMOVE(so_left, so_link);
if (LDAP_LIST_EMPTY(&sh->sh_sopool)) {
slap_replenish_sopool(sh);
}
so_right = LDAP_LIST_FIRST(&sh->sh_sopool);
LDAP_LIST_REMOVE(so_right, so_link);
so_right->so_ptr = (void *)((char *)so_left->so_ptr + (1 << j));
if (j == order + 1) {
ptr = so_left->so_ptr;
diff = (unsigned long)((char*)ptr -
(char*)sh->sh_base) >> (order+1);
sh->sh_map[order-order_start][diff>>3] |=
(1 << (diff & 0x7));
*ptr++ = size;
LDAP_LIST_INSERT_HEAD(
&sh->sh_free[j-1-order_start], so_right, so_link);
LDAP_LIST_INSERT_HEAD(&sh->sh_sopool, so_left, so_link);
return((void*)ptr);
} else {
LDAP_LIST_INSERT_HEAD(
&sh->sh_free[j-1-order_start], so_right, so_link);
LDAP_LIST_INSERT_HEAD(
&sh->sh_free[j-1-order_start], so_left, so_link);
}
}
}
/* FIXME: missing return; guessing we failed... */
}
Debug(LDAP_DEBUG_TRACE,
"sl_malloc %lu: ch_malloc\n",
(unsigned long) size, 0, 0);
return ch_malloc(size);
}
#define LIM_SQRT(t) /* some value < sqrt(max value of unsigned type t) */ \
((0UL|(t)-1) >>31>>31 > 1 ? ((t)1 <<32) - 1 : \
(0UL|(t)-1) >>31 ? 65535U : (0UL|(t)-1) >>15 ? 255U : 15U)
void *
slap_sl_calloc( ber_len_t n, ber_len_t size, void *ctx )
{
void *newptr;
ber_len_t total = n * size;
/* The sqrt test is a slight optimization: often avoids the division */
if ((n | size) <= LIM_SQRT(ber_len_t) || n == 0 || total/n == size) {
newptr = slap_sl_malloc( total, ctx );
memset( newptr, 0, n*size );
} else {
Debug(LDAP_DEBUG_ANY, "slap_sl_calloc(%lu,%lu) out of range\n",
(unsigned long) n, (unsigned long) size, 0);
assert(0);
exit(EXIT_FAILURE);
}
return newptr;
}
void *
slap_sl_realloc(void *ptr, ber_len_t size, void *ctx)
{
struct slab_heap *sh = ctx;
ber_len_t oldsize, *p = (ber_len_t *) ptr, *nextp;
void *newptr;
if (ptr == NULL)
return slap_sl_malloc(size, ctx);
/* Not our memory? */
if (No_sl_malloc || !sh || ptr < sh->sh_base || ptr >= sh->sh_end) {
/* Like ch_realloc(), except not trying a new context */
newptr = ber_memrealloc_x(ptr, size, NULL);
if (newptr) {
return newptr;
}
Debug(LDAP_DEBUG_ANY, "slap_sl_realloc of %lu bytes failed\n",
(unsigned long) size, 0, 0);
assert(0);
exit( EXIT_FAILURE );
}
if (size == 0) {
slap_sl_free(ptr, ctx);
return NULL;
}
oldsize = p[-1];
if (sh->sh_stack) {
/* Add room for head, round up to doubleword boundary */
size = (size + sizeof(ber_len_t) + Align-1) & -Align;
p--;
/* Never shrink blocks */
if (size <= oldsize) {
return ptr;
}
oldsize &= -2;
nextp = (ber_len_t *) ((char *) p + oldsize);
/* If reallocing the last block, try to grow it */
if (nextp == sh->sh_last) {
if (size < (ber_len_t) ((char *) sh->sh_end - (char *) p)) {
sh->sh_last = (char *) p + size;
p[0] = (p[0] & 1) | size;
return ptr;
}
/* Nowhere to grow, need to alloc and copy */
} else {
/* Slight optimization of the final realloc variant */
newptr = slap_sl_malloc(size-sizeof(ber_len_t), ctx);
AC_MEMCPY(newptr, ptr, oldsize-sizeof(ber_len_t));
/* Not last block, can just mark old region as free */
nextp[-1] = oldsize;
nextp[0] |= 1;
return newptr;
}
size -= sizeof(ber_len_t);
oldsize -= sizeof(ber_len_t);
} else if (oldsize > size) {
oldsize = size;
}
newptr = slap_sl_malloc(size, ctx);
AC_MEMCPY(newptr, ptr, oldsize);
slap_sl_free(ptr, ctx);
return newptr;
}
void
slap_sl_free(void *ptr, void *ctx)
{
struct slab_heap *sh = ctx;
ber_len_t size;
ber_len_t *p = ptr, *nextp, *tmpp;
if (!ptr)
return;
if (No_sl_malloc || !sh || ptr < sh->sh_base || ptr >= sh->sh_end) {
ber_memfree_x(ptr, NULL);
return;
}
size = *(--p);
if (sh->sh_stack) {
size &= -2;
nextp = (ber_len_t *) ((char *) p + size);
if (sh->sh_last != nextp) {
/* Mark it free: tail = size, head of next block |= 1 */
nextp[-1] = size;
nextp[0] |= 1;
/* We can't tell Valgrind about it yet, because we
* still need read/write access to this block for
* when we eventually get to reclaim it.
*/
} else {
/* Reclaim freed block(s) off tail */
while (*p & 1) {
p = (ber_len_t *) ((char *) p - p[-1]);
}
sh->sh_last = p;
VGMEMP_TRIM(sh, sh->sh_base,
(char *) sh->sh_last - (char *) sh->sh_base);
}
} else {
int size_shift, order_size;
struct slab_object *so;
unsigned long diff;
int i, inserted = 0, order = -1;
size_shift = size + sizeof(ber_len_t) - 1;
do {
order++;
} while (size_shift >>= 1);
for (i = order, tmpp = p; i <= sh->sh_maxorder; i++) {
order_size = 1 << (i+1);
diff = (unsigned long)((char*)tmpp - (char*)sh->sh_base) >> (i+1);
sh->sh_map[i-order_start][diff>>3] &= (~(1 << (diff & 0x7)));
if (diff == ((diff>>1)<<1)) {
if (!(sh->sh_map[i-order_start][(diff+1)>>3] &
(1<<((diff+1)&0x7)))) {
so = LDAP_LIST_FIRST(&sh->sh_free[i-order_start]);
while (so) {
if ((char*)so->so_ptr == (char*)tmpp) {
LDAP_LIST_REMOVE( so, so_link );
} else if ((char*)so->so_ptr ==
(char*)tmpp + order_size) {
LDAP_LIST_REMOVE(so, so_link);
break;
}
so = LDAP_LIST_NEXT(so, so_link);
}
if (so) {
if (i < sh->sh_maxorder) {
inserted = 1;
so->so_ptr = tmpp;
LDAP_LIST_INSERT_HEAD(&sh->sh_free[i-order_start+1],
so, so_link);
}
continue;
} else {
if (LDAP_LIST_EMPTY(&sh->sh_sopool)) {
slap_replenish_sopool(sh);
}
so = LDAP_LIST_FIRST(&sh->sh_sopool);
LDAP_LIST_REMOVE(so, so_link);
so->so_ptr = tmpp;
LDAP_LIST_INSERT_HEAD(&sh->sh_free[i-order_start],
so, so_link);
break;
Debug(LDAP_DEBUG_TRACE, "slap_sl_free: "
"free object not found while bit is clear.\n",
0, 0, 0);
assert(so != NULL);
}
} else {
if (!inserted) {
if (LDAP_LIST_EMPTY(&sh->sh_sopool)) {
slap_replenish_sopool(sh);
}
so = LDAP_LIST_FIRST(&sh->sh_sopool);
LDAP_LIST_REMOVE(so, so_link);
so->so_ptr = tmpp;
LDAP_LIST_INSERT_HEAD(&sh->sh_free[i-order_start],
so, so_link);
}
break;
}
} else {
if (!(sh->sh_map[i-order_start][(diff-1)>>3] &
(1<<((diff-1)&0x7)))) {
so = LDAP_LIST_FIRST(&sh->sh_free[i-order_start]);
while (so) {
if ((char*)so->so_ptr == (char*)tmpp) {
LDAP_LIST_REMOVE(so, so_link);
} else if ((char*)tmpp == (char *)so->so_ptr + order_size) {
LDAP_LIST_REMOVE(so, so_link);
tmpp = so->so_ptr;
break;
}
so = LDAP_LIST_NEXT(so, so_link);
}
if (so) {
if (i < sh->sh_maxorder) {
inserted = 1;
LDAP_LIST_INSERT_HEAD(&sh->sh_free[i-order_start+1], so, so_link);
continue;
}
} else {
if (LDAP_LIST_EMPTY(&sh->sh_sopool)) {
slap_replenish_sopool(sh);
}
so = LDAP_LIST_FIRST(&sh->sh_sopool);
LDAP_LIST_REMOVE(so, so_link);
so->so_ptr = tmpp;
LDAP_LIST_INSERT_HEAD(&sh->sh_free[i-order_start],
so, so_link);
break;
Debug(LDAP_DEBUG_TRACE, "slap_sl_free: "
"free object not found while bit is clear.\n",
0, 0, 0 );
assert(so != NULL);
}
} else {
if ( !inserted ) {
if (LDAP_LIST_EMPTY(&sh->sh_sopool)) {
slap_replenish_sopool(sh);
}
so = LDAP_LIST_FIRST(&sh->sh_sopool);
LDAP_LIST_REMOVE(so, so_link);
so->so_ptr = tmpp;
LDAP_LIST_INSERT_HEAD(&sh->sh_free[i-order_start],
so, so_link);
}
break;
}
}
}
}
}
/*
* Return the memory context of the current thread if the given block of
* memory belongs to it, otherwise return NULL.
*/
void *
slap_sl_context( void *ptr )
{
void *memctx;
struct slab_heap *sh;
if ( slapMode & SLAP_TOOL_MODE ) return NULL;
sh = GET_MEMCTX(ldap_pvt_thread_pool_context(), &memctx);
if (sh && ptr >= sh->sh_base && ptr <= sh->sh_end) {
return sh;
}
return NULL;
}
static struct slab_object *
slap_replenish_sopool(
struct slab_heap* sh
)
{
struct slab_object *so_block;
int i;
so_block = (struct slab_object *)ch_malloc(
SLAP_SLAB_SOBLOCK * sizeof(struct slab_object));
if ( so_block == NULL ) {
return NULL;
}
so_block[0].so_blockhead = 1;
LDAP_LIST_INSERT_HEAD(&sh->sh_sopool, &so_block[0], so_link);
for (i = 1; i < SLAP_SLAB_SOBLOCK; i++) {
so_block[i].so_blockhead = 0;
LDAP_LIST_INSERT_HEAD(&sh->sh_sopool, &so_block[i], so_link );
}
return so_block;
}
#ifdef SLAPD_UNUSED
static void
print_slheap(int level, void *ctx)
{
struct slab_heap *sh = ctx;
struct slab_object *so;
int i, j, once = 0;
if (!ctx) {
Debug(level, "NULL memctx\n", 0, 0, 0);
return;
}
Debug(level, "sh->sh_maxorder=%d\n", sh->sh_maxorder, 0, 0);
for (i = order_start; i <= sh->sh_maxorder; i++) {
once = 0;
Debug(level, "order=%d\n", i, 0, 0);
for (j = 0; j < (1<<(sh->sh_maxorder-i))/8; j++) {
Debug(level, "%02x ", sh->sh_map[i-order_start][j], 0, 0);
once = 1;
}
if (!once) {
Debug(level, "%02x ", sh->sh_map[i-order_start][0], 0, 0);
}
Debug(level, "\n", 0, 0, 0);
Debug(level, "free list:\n", 0, 0, 0);
so = LDAP_LIST_FIRST(&sh->sh_free[i-order_start]);
while (so) {
Debug(level, "%p\n", so->so_ptr, 0, 0);
so = LDAP_LIST_NEXT(so, so_link);
}
}
}
#endif