static int
internal_function
heap_trim(heap_info *heap, size_t pad)
{
mstate ar_ptr = heap->ar_ptr;
unsigned long pagesz = GLRO(dl_pagesize);
mchunkptr top_chunk = top(ar_ptr), p, bck, fwd;
heap_info *prev_heap;
long new_size, top_size, extra, prev_size, misalign;
/* Can this heap go away completely? */
while(top_chunk == chunk_at_offset(heap, sizeof(*heap))) {
prev_heap = heap->prev;
prev_size = prev_heap->size - (MINSIZE-2*SIZE_SZ);
p = chunk_at_offset(prev_heap, prev_size);
/* fencepost must be properly aligned. */
misalign = ((long) p) & MALLOC_ALIGN_MASK;
p = chunk_at_offset(prev_heap, prev_size - misalign);
assert(p->size == (0|PREV_INUSE)); /* must be fencepost */
p = prev_chunk(p);
new_size = chunksize(p) + (MINSIZE-2*SIZE_SZ) + misalign;
assert(new_size>0 && new_size<(long)(2*MINSIZE));
if(!prev_inuse(p))
new_size += p->prev_size;
assert(new_size>0 && new_size<HEAP_MAX_SIZE);
if(new_size + (HEAP_MAX_SIZE - prev_heap->size) < pad + MINSIZE + pagesz)
break;
ar_ptr->system_mem -= heap->size;
arena_mem -= heap->size;
delete_heap(heap);
heap = prev_heap;
if(!prev_inuse(p)) { /* consolidate backward */
p = prev_chunk(p);
unlink(p, bck, fwd);
}
assert(((unsigned long)((char*)p + new_size) & (pagesz-1)) == 0);
assert( ((char*)p + new_size) == ((char*)heap + heap->size) );
top(ar_ptr) = top_chunk = p;
set_head(top_chunk, new_size | PREV_INUSE);
/*check_chunk(ar_ptr, top_chunk);*/
}
top_size = chunksize(top_chunk);
extra = (top_size - pad - MINSIZE - 1) & ~(pagesz - 1);
if(extra < (long)pagesz)
return 0;
/* Try to shrink. */
if(shrink_heap(heap, extra) != 0)
return 0;
ar_ptr->system_mem -= extra;
arena_mem -= extra;
/* Success. Adjust top accordingly. */
set_head(top_chunk, (top_size - extra) | PREV_INUSE);
/*check_chunk(ar_ptr, top_chunk);*/
return 1;
}
static void
do_gc()
{
DBG(("start gc"));
clear_all_bitmaps();
sml_rootset_enum_ptr(mark);
sml_malloc_pop_and_mark(mark);
/* check finalization */
sml_check_finalizer(mark);
sweep();
shrink_heap(1);
/* sweep malloc heap */
sml_malloc_sweep();
DBG(("gc finished."));
}
static int
internal_function
heap_trim (heap_info *heap, size_t pad)
{
mstate ar_ptr = heap->ar_ptr;
unsigned long pagesz = GLRO (dl_pagesize);
mchunkptr top_chunk = top (ar_ptr), p, bck, fwd;
heap_info *prev_heap;
long new_size, top_size, top_area, extra, prev_size, misalign;
/* Can this heap go away completely? */
while (top_chunk == chunk_at_offset (heap, sizeof (*heap)))
{
prev_heap = heap->prev;
prev_size = prev_heap->size - (MINSIZE - 2 * SIZE_SZ);
p = chunk_at_offset (prev_heap, prev_size);
/* fencepost must be properly aligned. */
misalign = ((long) p) & MALLOC_ALIGN_MASK;
p = chunk_at_offset (prev_heap, prev_size - misalign);
assert (p->size == (0 | PREV_INUSE)); /* must be fencepost */
p = prev_chunk (p);
new_size = chunksize (p) + (MINSIZE - 2 * SIZE_SZ) + misalign;
assert (new_size > 0 && new_size < (long) (2 * MINSIZE));
if (!prev_inuse (p))
new_size += p->prev_size;
assert (new_size > 0 && new_size < HEAP_MAX_SIZE);
if (new_size + (HEAP_MAX_SIZE - prev_heap->size) < pad + MINSIZE + pagesz)
break;
ar_ptr->system_mem -= heap->size;
arena_mem -= heap->size;
LIBC_PROBE (memory_heap_free, 2, heap, heap->size);
delete_heap (heap);
heap = prev_heap;
if (!prev_inuse (p)) /* consolidate backward */
{
p = prev_chunk (p);
unlink (ar_ptr, p, bck, fwd);
}
assert (((unsigned long) ((char *) p + new_size) & (pagesz - 1)) == 0);
assert (((char *) p + new_size) == ((char *) heap + heap->size));
top (ar_ptr) = top_chunk = p;
set_head (top_chunk, new_size | PREV_INUSE);
/*check_chunk(ar_ptr, top_chunk);*/
}
/* Uses similar logic for per-thread arenas as the main arena with systrim
by preserving the top pad and at least a page. */
top_size = chunksize (top_chunk);
top_area = top_size - MINSIZE - 1;
if (top_area <= pad)
return 0;
extra = ALIGN_DOWN(top_area - pad, pagesz);
if ((unsigned long) extra < mp_.trim_threshold)
return 0;
/* Try to shrink. */
if (shrink_heap (heap, extra) != 0)
return 0;
ar_ptr->system_mem -= extra;
arena_mem -= extra;
/* Success. Adjust top accordingly. */
set_head (top_chunk, (top_size - extra) | PREV_INUSE);
/*check_chunk(ar_ptr, top_chunk);*/
return 1;
}