diff options
| -rw-r--r-- | ChangeLog | 6 | ||||
| -rw-r--r-- | Src/mem.c | 24 |
2 files changed, 27 insertions, 3 deletions
diff --git a/ChangeLog b/ChangeLog index 0b9cc79df..2d18e9d67 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,7 @@ +2011-05-07 Barton E. Schaefer <schaefer@zsh.org> + + * 29175 (w/comment typo fixed): Src/mem.c: optimize freeheap. + 2011-05-07 Frank Terbeck <ft@bewatermyfriend.org> * 29170: Doc/Zsh/contrib.yo: vcs_info: Clarify check-for-changes @@ -14598,5 +14602,5 @@ ***************************************************** * This is used by the shell to define $ZSH_PATCHLEVEL -* $Revision: 1.5280 $ +* $Revision: 1.5281 $ ***************************************************** diff --git a/Src/mem.c b/Src/mem.c index 1a3e75997..9b80f188c 100644 --- a/Src/mem.c +++ b/Src/mem.c @@ -220,8 +220,28 @@ freeheap(void) h_free++; #endif + /* At this point we used to do: fheap = NULL; - for (h = heaps; h; h = hn) { + * + * 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 + * 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 + * 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. + */ + for (h = (fheap ? fheap : heaps); h; h = hn) { hn = h->next; if (h->sp) { #ifdef ZSH_MEM_DEBUG @@ -242,7 +262,7 @@ freeheap(void) if (hl) hl->next = NULL; else - heaps = NULL; + heaps = fheap = NULL; unqueue_signals(); } |