Minor performance improvement to kern_malloc.c that increases the

probability of reuse of recently freed memory.  This improves cache
hit stats on cached memory, and improves at least fork speed consistancy.
This commit is contained in:
John Dyson 1996-05-18 22:33:13 +00:00
parent 9957f86096
commit 14bf02f8f4

View File

@ -31,7 +31,7 @@
* SUCH DAMAGE.
*
* @(#)kern_malloc.c 8.3 (Berkeley) 1/4/94
* $Id: kern_malloc.c,v 1.21 1996/05/02 14:20:20 phk Exp $
* $Id: kern_malloc.c,v 1.22 1996/05/10 19:28:48 wollman Exp $
*/
#include <sys/param.h>
@ -351,12 +351,28 @@ free(addr, type)
wakeup((caddr_t)ksp);
ksp->ks_inuse--;
#endif
#ifdef OLD_MALLOC_MEMORY_POLICY
if (kbp->kb_next == NULL)
kbp->kb_next = addr;
else
((struct freelist *)kbp->kb_last)->next = addr;
freep->next = NULL;
kbp->kb_last = addr;
#else
/*
* Return memory to the head of the queue for quick reuse. This
* can improve performance by improving the probability of the
* item being in the cache when it is reused.
*/
if (kbp->kb_next == NULL) {
kbp->kb_next = addr;
kbp->kb_last = addr;
freep->next = NULL;
} else {
freep->next = kbp->kb_next;
kbp->kb_next = addr;
}
#endif
splx(s);
}