From bf094836d816d325bfddfca3b1e23b918bcb4255 Mon Sep 17 00:00:00 2001 From: Ulrich Drepper Date: Thu, 17 Apr 1997 23:22:29 +0000 Subject: (fREe): Small optimization. Before returning, 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(). --- malloc/malloc.c | 117 +++++++++++++++++++++++++++++++++++++++++--------------- 1 file changed, 87 insertions(+), 30 deletions(-) (limited to 'malloc') diff --git a/malloc/malloc.c b/malloc/malloc.c index dee92e37c6..9d4d03c073 100644 --- a/malloc/malloc.c +++ b/malloc/malloc.c @@ -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); -- cgit v1.2.3