//This function is equal to mspace_free
//replacing PREACTION with 0 and POSTACTION with nothing
static void mspace_free_lockless(mspace msp, void* mem)
{
if (mem != 0) {
mchunkptr p = mem2chunk(mem);
#if FOOTERS
mstate fm = get_mstate_for(p);
msp = msp; /* placate people compiling -Wunused */
#else /* FOOTERS */
mstate fm = (mstate)msp;
#endif /* FOOTERS */
if (!ok_magic(fm)) {
USAGE_ERROR_ACTION(fm, p);
return;
}
if (!0){//PREACTION(fm)) {
check_inuse_chunk(fm, p);
if (RTCHECK(ok_address(fm, p) && ok_inuse(p))) {
size_t psize = chunksize(p);
mchunkptr next = chunk_plus_offset(p, psize);
s_allocated_memory -= psize;
if (!pinuse(p)) {
size_t prevsize = p->prev_foot;
if (is_mmapped(p)) {
psize += prevsize + MMAP_FOOT_PAD;
if (CALL_MUNMAP((char*)p - prevsize, psize) == 0)
fm->footprint -= psize;
goto postaction;
}
else {
mchunkptr prev = chunk_minus_offset(p, prevsize);
psize += prevsize;
p = prev;
if (RTCHECK(ok_address(fm, prev))) { /* consolidate backward */
if (p != fm->dv) {
unlink_chunk(fm, p, prevsize);
}
else if ((next->head & INUSE_BITS) == INUSE_BITS) {
fm->dvsize = psize;
set_free_with_pinuse(p, psize, next);
goto postaction;
}
}
else
goto erroraction;
}
}
if (RTCHECK(ok_next(p, next) && ok_pinuse(next))) {
if (!cinuse(next)) { /* consolidate forward */
if (next == fm->top) {
size_t tsize = fm->topsize += psize;
fm->top = p;
p->head = tsize | PINUSE_BIT;
if (p == fm->dv) {
fm->dv = 0;
fm->dvsize = 0;
}
if (should_trim(fm, tsize))
sys_trim(fm, 0);
goto postaction;
}
else if (next == fm->dv) {
size_t dsize = fm->dvsize += psize;
fm->dv = p;
set_size_and_pinuse_of_free_chunk(p, dsize);
goto postaction;
}
else {
size_t nsize = chunksize(next);
psize += nsize;
unlink_chunk(fm, next, nsize);
set_size_and_pinuse_of_free_chunk(p, psize);
if (p == fm->dv) {
fm->dvsize = psize;
goto postaction;
}
}
}
else
set_free_with_pinuse(p, psize, next);
if (is_small(psize)) {
insert_small_chunk(fm, p, psize);
check_free_chunk(fm, p);
}
else {
tchunkptr tp = (tchunkptr)p;
insert_large_chunk(fm, tp, psize);
check_free_chunk(fm, p);
if (--fm->release_checks == 0)
release_unused_segments(fm);
}
goto postaction;
}
}
erroraction:
USAGE_ERROR_ACTION(fm, p);
postaction:
;//POSTACTION(fm);
}
}
}
/* ------------------------------ free ------------------------------ */
void free(void* mem)
{
mstate av;
mchunkptr p; /* chunk corresponding to mem */
size_t size; /* its size */
mfastbinptr* fb; /* associated fastbin */
mchunkptr nextchunk; /* next contiguous chunk */
size_t nextsize; /* its size */
int nextinuse; /* true if nextchunk is used */
size_t prevsize; /* size of previous contiguous chunk */
mchunkptr bck; /* misc temp for linking */
mchunkptr fwd; /* misc temp for linking */
/* free(0) has no effect */
if (mem == NULL)
return;
__MALLOC_LOCK;
av = get_malloc_state();
p = mem2chunk(mem);
size = chunksize(p);
check_inuse_chunk(p);
/*
If eligible, place chunk on a fastbin so it can be found
and used quickly in malloc.
*/
if ((unsigned long)(size) <= (unsigned long)(av->max_fast)
#if TRIM_FASTBINS
/* If TRIM_FASTBINS set, don't place chunks
bordering top into fastbins */
&& (chunk_at_offset(p, size) != av->top)
#endif
) {
set_fastchunks(av);
fb = &(av->fastbins[fastbin_index(size)]);
p->fd = *fb;
*fb = p;
}
/*
Consolidate other non-mmapped chunks as they arrive.
*/
else if (!chunk_is_mmapped(p)) {
set_anychunks(av);
nextchunk = chunk_at_offset(p, size);
nextsize = chunksize(nextchunk);
/* consolidate backward */
if (!prev_inuse(p)) {
prevsize = p->prev_size;
size += prevsize;
p = chunk_at_offset(p, -((long) prevsize));
unlink(p, bck, fwd);
}
if (nextchunk != av->top) {
/* get and clear inuse bit */
nextinuse = inuse_bit_at_offset(nextchunk, nextsize);
set_head(nextchunk, nextsize);
/* consolidate forward */
if (!nextinuse) {
unlink(nextchunk, bck, fwd);
size += nextsize;
}
/*
Place the chunk in unsorted chunk list. Chunks are
not placed into regular bins until after they have
been given one chance to be used in malloc.
*/
bck = unsorted_chunks(av);
fwd = bck->fd;
p->bk = bck;
p->fd = fwd;
bck->fd = p;
fwd->bk = p;
set_head(p, size | PREV_INUSE);
set_foot(p, size);
check_free_chunk(p);
}
/*
If the chunk borders the current high end of memory,
consolidate into top
*/
else {
size += nextsize;
set_head(p, size | PREV_INUSE);
av->top = p;
check_chunk(p);
}
/*
If freeing a large space, consolidate possibly-surrounding
chunks. Then, if the total unused topmost memory exceeds trim
threshold, ask malloc_trim to reduce top.
Unless max_fast is 0, we don't know if there are fastbins
bordering top, so we cannot tell for sure whether threshold
has been reached unless fastbins are consolidated. But we
don't want to consolidate on each free. As a compromise,
consolidation is performed if FASTBIN_CONSOLIDATION_THRESHOLD
is reached.
*/
if ((unsigned long)(size) >= FASTBIN_CONSOLIDATION_THRESHOLD) {
if (have_fastchunks(av))
__malloc_consolidate(av);
if ((unsigned long)(chunksize(av->top)) >=
(unsigned long)(av->trim_threshold))
__malloc_trim(av->top_pad, av);
}
}
/*
If the chunk was allocated via mmap, release via munmap()
Note that if HAVE_MMAP is false but chunk_is_mmapped is
true, then user must have overwritten memory. There's nothing
we can do to catch this error unless DEBUG is set, in which case
check_inuse_chunk (above) will have triggered error.
*/
else {
size_t offset = p->prev_size;
av->n_mmaps--;
av->mmapped_mem -= (size + offset);
munmap((char*)p - offset, size + offset);
}
__MALLOC_UNLOCK;
}
static void
_int_free (mstate av, mchunkptr p, int have_lock)
{
...
else if (!chunk_is_mmapped(p)) {
...
nextchunk = chunk_at_offset(p, size);
...
nextsize = chunksize(nextchunk);
...
/* consolidate backward */
if (!prev_inuse(p)) {
prevsize = p->prev_size;
size += prevsize;
p = chunk_at_offset(p, -((long) prevsize));
unlink(p, bck, fwd);
}
if (nextchunk != av->top) {
/* get and clear inuse bit */
nextinuse = inuse_bit_at_offset(nextchunk, nextsize);
/* consolidate forward */
if (!nextinuse) {
unlink(nextchunk, bck, fwd);
size += nextsize;
} else
clear_inuse_bit_at_offset(nextchunk, 0);
/*
Place the chunk in unsorted chunk list. Chunks are
not placed into regular bins until after they have
been given one chance to be used in malloc.
*/
bck = unsorted_chunks(av);
fwd = bck->fd;
if (__glibc_unlikely (fwd->bk != bck))
{
errstr = "free(): corrupted unsorted chunks";
goto errout;
}
p->fd = fwd;
p->bk = bck;
if (!in_smallbin_range(size))
{
p->fd_nextsize = NULL;
p->bk_nextsize = NULL;
}
bck->fd = p;
fwd->bk = p;
set_head(p, size | PREV_INUSE);
set_foot(p, size);
check_free_chunk(av, p);
}
/*
If the chunk borders the current high end of memory,
consolidate into top
*/
else {
size += nextsize;
set_head(p, size | PREV_INUSE);
av->top = p;
check_chunk(av, p);
}
...
}
