mirrors
/
zsh
mirror of git://git.code.sf.net/p/zsh/code
1
0
Fork 0
Code Releases Activity

29175: optimize freeheap

This commit is contained in:
Bart Schaefer 2011-05-07 19:32:57 +00:00
parent 0ba32c9130
commit 6150565494
2 changed files with 27 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
ChangeLog
View File

@ -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 $
*****************************************************

24
Src/mem.c
View File

@ -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();
}