diff options
| -rw-r--r-- | ChangeLog | 5 | ||||
| -rw-r--r-- | Src/mem.c | 24 |
2 files changed, 14 insertions, 15 deletions
@@ -1,3 +1,8 @@ +2014-01-22 Barton E. Schaefer <schaefer@zsh.org> + + * unposted: Src/mem.c: reformulate 32285 to lift the fheap->sp + test out of the loop, improve commentary + 2014-01-19 Barton E. Schaefer <schaefer@zsh.org> * 32294 (plus typo fix): Src/utils.c: prevent buffer overflow when @@ -319,23 +319,26 @@ freeheap(void) h_free++; #endif - /* At this point we used to do: - fheap = NULL; - * + /* * When pushheap() is called, it sweeps over the entire heaps list of * arenas and marks every one of them with the amount of free space in * that arena at that moment. zhalloc() is then allowed to grab bits * out of any of those arenas that have free space. * - * With the above reset of fheap, the loop below sweeps back over the + * 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 * 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, there doesn't seem to be any reason to reset fheap before - * beginning this loop. Either it's already correct, or it has never + * 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 */ + /* + * 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 * the scan wherever the last pass [or the last popheap()] left off. @@ -367,15 +370,6 @@ freeheap(void) } #endif } else { - if (h == fheap && h != heaps) { - /* - * When deallocating the last arena with free space, - * loop back through the list to find another one. - */ - fheap = NULL; - hn = heaps; - continue; - } #ifdef USE_MMAP munmap((void *) h, h->size); #else |