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(fREe): Small optimization. Before returning,

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add fast check whether the heap containing top can go away.
(mALLOc, rEALLOc, cALLOc, mEMALIGn): When
failing to allocate a new chunk, also try the main_arena.  It may
be that we are only running out of mmapped regions, and other
arenas cannot be enlarged sufficiently.
(new_heap, malloc_extend_top): Handle top_pad more consistently,
i.e. only in new_heap().
This commit is contained in:
Ulrich Drepper 1997-04-17 23:22:29 +00:00
parent 0b67eee38b
commit bf094836d8
1 changed files with 87 additions and 30 deletions
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117
malloc/malloc.c
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@ -1801,11 +1801,16 @@ new_heap(size) size_t size;
unsigned long ul;
heap_info *h;
if(size < HEAP_MIN_SIZE)
if(size+top_pad < HEAP_MIN_SIZE)
size = HEAP_MIN_SIZE;
size = (size + page_mask) & ~page_mask;
if(size > HEAP_MAX_SIZE)
else if(size+top_pad <= HEAP_MAX_SIZE)
size += top_pad;
else if(size > HEAP_MAX_SIZE)
return 0;
else
size = HEAP_MAX_SIZE;
size = (size + page_mask) & ~page_mask;
p1 = (char *)MMAP(HEAP_MAX_SIZE<<1, PROT_NONE);
if(p1 == (char *)-1)
return 0;
@ -2228,9 +2233,11 @@ static void malloc_extend_top(ar_ptr, nb) arena *ar_ptr; INTERNAL_SIZE_T nb;
(brk < old_end && old_top != initial_top(&main_arena)))
return;
#if defined(_LIBC) || defined(MALLOC_HOOKS)
/* Call the `morecore' hook if necessary. */
if (__after_morecore_hook)
(*__after_morecore_hook) ();
#endif
sbrked_mem += sbrk_size;
@ -2260,9 +2267,11 @@ static void malloc_extend_top(ar_ptr, nb) arena *ar_ptr; INTERNAL_SIZE_T nb;
new_brk = (char*)(MORECORE (correction));
if (new_brk == (char*)(MORECORE_FAILURE)) return;
#if defined(_LIBC) || defined(MALLOC_HOOKS)
/* Call the `morecore' hook if necessary. */
if (__after_morecore_hook)
(*__after_morecore_hook) ();
(*__after_morecore_hook) ();
#endif
sbrked_mem += correction;
@ -2303,7 +2312,7 @@ static void malloc_extend_top(ar_ptr, nb) arena *ar_ptr; INTERNAL_SIZE_T nb;
}
/* A new heap must be created. */
heap = new_heap(nb + top_pad + (MINSIZE + sizeof(*heap)));
heap = new_heap(nb + (MINSIZE + sizeof(*heap)));
if(!heap)
return;
heap->ar_ptr = ar_ptr;
@ -2425,12 +2434,21 @@ Void_t* mALLOc(bytes) size_t bytes;
#endif
nb = request2size(bytes);
arena_get(ar_ptr, nb + top_pad);
arena_get(ar_ptr, nb);
if(!ar_ptr)
return 0;
victim = chunk_alloc(ar_ptr, nb);
(void)mutex_unlock(&ar_ptr->mutex);
return victim ? chunk2mem(victim) : 0;
if(!victim) {
/* Maybe the failure is due to running out of mmapped areas. */
if(ar_ptr != &main_arena) {
(void)mutex_lock(&main_arena.mutex);
victim = chunk_alloc(&main_arena, nb);
(void)mutex_unlock(&main_arena.mutex);
}
if(!victim) return 0;
}
return chunk2mem(victim);
}
static mchunkptr
@ -2792,8 +2810,6 @@ chunk_free(ar_ptr, p) arena *ar_ptr; mchunkptr p;
return;
}
set_head(next, nextsz); /* clear inuse bit */
islr = 0;
if (!(hd & PREV_INUSE)) /* consolidate backward */
@ -2820,12 +2836,29 @@ chunk_free(ar_ptr, p) arena *ar_ptr; mchunkptr p;
}
else
unlink(next, bck, fwd);
next = chunk_at_offset(p, sz);
}
else
set_head(next, nextsz); /* clear inuse bit */
set_head(p, sz | PREV_INUSE);
set_foot(p, sz);
next->prev_size = sz;
if (!islr)
frontlink(ar_ptr, p, sz, idx, bck, fwd);
#ifndef NO_THREADS
/* Check whether the heap containing top can go away now. */
if(next->size < MINSIZE &&
(unsigned long)sz > trim_threshold &&
ar_ptr != &main_arena) { /* fencepost */
heap_info* heap = heap_for_ptr(top(ar_ptr));
if(top(ar_ptr) == chunk_at_offset(heap, sizeof(*heap)) &&
heap->prev == heap_for_ptr(p))
heap_trim(heap, top_pad);
}
#endif
}
@ -3063,8 +3096,16 @@ arena* ar_ptr; mchunkptr oldp; INTERNAL_SIZE_T oldsize, nb;
newp = chunk_alloc (ar_ptr, nb);
if (newp == 0) /* propagate failure */
return 0;
if (newp == 0) {
/* Maybe the failure is due to running out of mmapped areas. */
if (ar_ptr != &main_arena) {
(void)mutex_lock(&main_arena.mutex);
newp = chunk_alloc(&main_arena, nb);
(void)mutex_unlock(&main_arena.mutex);
}
if (newp == 0) /* propagate failure */
return 0;
}
/* Avoid copy if newp is next chunk after oldp. */
/* (This can only happen when new chunk is sbrk'ed.) */
@ -3159,7 +3200,16 @@ Void_t* mEMALIGn(alignment, bytes) size_t alignment; size_t bytes;
return 0;
p = chunk_align(ar_ptr, nb, alignment);
(void)mutex_unlock(&ar_ptr->mutex);
return p ? chunk2mem(p) : NULL;
if(!p) {
/* Maybe the failure is due to running out of mmapped areas. */
if(ar_ptr != &main_arena) {
(void)mutex_lock(&main_arena.mutex);
p = chunk_align(&main_arena, nb, alignment);
(void)mutex_unlock(&main_arena.mutex);
}
if(!p) return 0;
}
return chunk2mem(p);
}
static mchunkptr
@ -3329,31 +3379,34 @@ Void_t* cALLOc(n, elem_size) size_t n; size_t elem_size;
/* Only clearing follows, so we can unlock early. */
(void)mutex_unlock(&ar_ptr->mutex);
if (p == 0)
return 0;
else
{
mem = chunk2mem(p);
if (p == 0) {
/* Maybe the failure is due to running out of mmapped areas. */
if(ar_ptr != &main_arena) {
(void)mutex_lock(&main_arena.mutex);
p = chunk_alloc(&main_arena, sz);
(void)mutex_unlock(&main_arena.mutex);
}
if (p == 0) return 0;
}
mem = chunk2mem(p);
/* Two optional cases in which clearing not necessary */
/* Two optional cases in which clearing not necessary */
#if HAVE_MMAP
if (chunk_is_mmapped(p)) return mem;
if (chunk_is_mmapped(p)) return mem;
#endif
csz = chunksize(p);
csz = chunksize(p);
#if MORECORE_CLEARS
if (p == oldtop && csz > oldtopsize)
{
/* clear only the bytes from non-freshly-sbrked memory */
csz = oldtopsize;
}
if (p == oldtop && csz > oldtopsize) {
/* clear only the bytes from non-freshly-sbrked memory */
csz = oldtopsize;
}
#endif
MALLOC_ZERO(mem, csz - SIZE_SZ);
return mem;
}
MALLOC_ZERO(mem, csz - SIZE_SZ);
return mem;
}
/*
@ -3444,9 +3497,11 @@ main_trim(pad) size_t pad;
new_brk = (char*)(MORECORE (-extra));
#if defined(_LIBC) || defined(MALLOC_HOOKS)
/* Call the `morecore' hook if necessary. */
if (__after_morecore_hook)
(*__after_morecore_hook) ();
#endif
if (new_brk == (char*)(MORECORE_FAILURE)) { /* sbrk failed? */
/* Try to figure out what we have */
@ -3692,8 +3747,9 @@ void mALLOC_STATs()
#endif
#if !defined(NO_THREADS) && MALLOC_DEBUG > 1
if(ar_ptr != &main_arena) {
heap_info* heap;
(void)mutex_lock(&ar_ptr->mutex);
heap_info *heap = heap_for_ptr(top(ar_ptr));
heap = heap_for_ptr(top(ar_ptr));
while(heap) { dump_heap(heap); heap = heap->prev; }
(void)mutex_unlock(&ar_ptr->mutex);
}
@ -3709,6 +3765,7 @@ void mALLOC_STATs()
#endif
#if HAVE_MMAP
fprintf(stderr, "max mmap regions = %10u\n", (unsigned int)max_n_mmaps);
fprintf(stderr, "max mmap bytes = %10lu\n", max_mmapped_mem);
#endif
#if THREAD_STATS
fprintf(stderr, "heaps created = %10d\n", stat_n_heaps);