diff options
Diffstat (limited to 'Src/mem.c')
| -rw-r--r-- | Src/mem.c | 65 |
1 files changed, 52 insertions, 13 deletions
@@ -294,7 +294,7 @@ pushheap(void) #endif for (h = heaps; h; h = h->next) { - DPUTS(!h->used, "BUG: empty heap"); + DPUTS(!h->used && h->next, "BUG: empty heap"); hs = (Heapstack) zalloc(sizeof(*hs)); hs->next = h->sp; h->sp = hs; @@ -334,17 +334,15 @@ freeheap(void) * * Whenever fheap is NULL here, the loop below sweeps back over the * entire heap list again, resetting the free space in every arena to - * the amount stashed by pushheap() and finding the first arena with + * the amount stashed by pushheap() and finding the arena with the most * free space to optimize zhalloc()'s next search. When there's a lot * of stuff already on the heap, this is an enormous amount of work, * and performance goes to hell. * - * However, if the arena to which fheap points is unused, we want to - * free it, so we have no choice but to do the sweep for a new fheap. - */ - if (fheap && !fheap->sp) - fheap = NULL; /* We used to do this unconditionally */ - /* + * Therefore, we defer freeing the most recently allocated arena until + * we reach popheap(). This may fail to reclaim some space in earlier + * arenas. + * * In other cases, either fheap is already correct, or it has never * been set and this loop will do it, or it'll be reset from scratch * on the next popheap(). So all that's needed here is to pick up @@ -361,7 +359,11 @@ freeheap(void) memset(arena(h) + h->sp->used, 0xff, h->used - h->sp->used); #endif h->used = h->sp->used; - if (!fheap && h->used < ARENA_SIZEOF(h)) + if (!fheap) { + if (h->used < ARENA_SIZEOF(h)) + fheap = h; + } else if (ARENA_SIZEOF(h) - h->used > + ARENA_SIZEOF(fheap) - fheap->used) fheap = h; hl = h; #ifdef ZSH_HEAP_DEBUG @@ -384,6 +386,26 @@ freeheap(void) VALGRIND_MEMPOOL_TRIM((char *)h, (char *)arena(h), h->used); #endif } else { + if (h->next) { + /* We want to cut this out of the arena list if we can */ + if (h == heaps) + hl = heaps = h->next; + else if (hl && hl->next == h) + hl->next = h->next; + else { + DPUTS(hl, "hl->next != h when freeing"); + hl = h; + continue; + } + h->next = NULL; + } else { + /* Leave an empty arena at the end until popped */ + h->used = 0; + fheap = hl = h; + break; + } + if (fheap == h) + fheap = NULL; #ifdef USE_MMAP munmap((void *) h, h->size); #else @@ -441,12 +463,29 @@ popheap(void) #ifdef ZSH_VALGRIND VALGRIND_MEMPOOL_TRIM((char *)h, (char *)arena(h), h->used); #endif - if (!fheap && h->used < ARENA_SIZEOF(h)) + if (!fheap) { + if (h->used < ARENA_SIZEOF(h)) + fheap = h; + } else if (ARENA_SIZEOF(h) - h->used > + ARENA_SIZEOF(fheap) - fheap->used) fheap = h; zfree(hs, sizeof(*hs)); hl = h; } else { + if (h->next) { + /* We want to cut this out of the arena list if we can */ + if (h == heaps) + hl = heaps = h->next; + else if (hl && hl->next == h) + hl->next = h->next; + else { + DPUTS(hl, "hl->next != h when popping"); + hl = h; + continue; + } + h->next = NULL; + } #ifdef USE_MMAP munmap((void *) h, h->size); #else @@ -524,7 +563,7 @@ zheapptr(void *p) mod_export void * zhalloc(size_t size) { - Heap h; + Heap h, hp = NULL; size_t n; #ifdef ZSH_VALGRIND size_t req_size = size; @@ -546,6 +585,7 @@ zhalloc(size_t size) for (h = ((fheap && ARENA_SIZEOF(fheap) >= (size + fheap->used)) ? fheap : heaps); h; h = h->next) { + hp = h; if (ARENA_SIZEOF(h) >= (n = size + h->used)) { void *ret; @@ -566,7 +606,6 @@ zhalloc(size_t size) } } { - Heap hp; /* not found, allocate new heap */ #if defined(ZSH_MEM) && !defined(USE_MMAP) static int called = 0; @@ -575,7 +614,6 @@ zhalloc(size_t size) #endif n = HEAP_ARENA_SIZE > size ? HEAPSIZE : size + sizeof(*h); - for (hp = NULL, h = heaps; h; hp = h, h = h->next); #ifdef USE_MMAP h = mmap_heap_alloc(&n); @@ -607,6 +645,7 @@ zhalloc(size_t size) VALGRIND_MEMPOOL_ALLOC((char *)h, (char *)arena(h), req_size); #endif + DPUTS(hp && hp->next, "failed to find end of chain in zhalloc"); if (hp) hp->next = h; else |