[PATCH 2/2] pid: reduce code size by using a pointer to iterate over array

André Goddard Rosa
2009-11-22T12:18:36Z

It decreases code size by 16 bytes on my gcc 4.4.1 on Core 2:
text data bss dec hex filename
4314 2216 8 6538 198a kernel/pid.o-BEFORE
4298 2216 8 6522 197a kernel/pid.o-AFTER

Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com>
---
kernel/pid.c | 5 ++---
1 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/kernel/pid.c b/kernel/pid.c
index 55fd590..2e17c9c 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -269,12 +269,11 @@ struct pid *alloc_pid(struct pid_namespace *ns)
for (type = 0; type < PIDTYPE_MAX; ++type)
INIT_HLIST_HEAD(&pid->tasks[type]);

+ upid = pid->numbers + ns->level;
spin_lock_irq(&pidmap_lock);
- for (i = ns->level; i >= 0; i--) {
- upid = &pid->numbers[i];
+ for ( ; upid >= pid->numbers; --upid)
hlist_add_head_rcu(&upid->pid_chain,
&pid_hash[pid_hashfn(upid->nr, upid->ns)]);
- }
spin_unlock_irq(&pidmap_lock);

out:
--
1.6.5.3.298.g39add