slob: fix free block merging at head of subpage

We weren't merging freed blocks at the beginning of the free list. Fixing this showed a 2.5% efficiency improvement in a userspace test harness. Signed-off-by: Matt Mackall <mpm@selenic.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mariux64 · Feb 5, 2008 · 679299b · 679299b
1 parent 8bc3be2
commit 679299b
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/mm/slob.c b/mm/slob.c
@@ -398,6 +398,10 @@ static void slob_free(void *block, int size)
 	sp->units += units;
 
 	if (b < sp->free) {
+		if (b + units == sp->free) {
+			units += slob_units(sp->free);
+			sp->free = slob_next(sp->free);
+		}
 		set_slob(b, units, sp->free);
 		sp->free = b;
 	} else {