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>
diff --git a/mm/slob.c b/mm/slob.c
index 773a7aa..c56c5e5 100644
--- a/mm/slob.c
+++ b/mm/slob.c
@@ -398,6 +398,10 @@
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 {