[RFC PATCH 2/4] SCHED_DEADLINE cpu heap code clarification/refactory.

[Tommaso Cucinotta]

1. heapify up factored out in new dedicated function heapify_up()
   (avoids repeatition of same code)
2. call to cpudl_change_key() replaced with heapify_up() when
   cpudl_set actually inserts a new node in the heap

Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Juri Lelli <juri.le...@arm.com>
Cc: Luca Abeni <luca.ab...@unitn.it>
Reviewed-by: Luca Abeni <luca.ab...@unitn.it>
Signed-off-by: Tommaso Cucinotta <tommaso.cucino...@sssup.it>
---
 kernel/sched/cpudeadline.c | 38 +++++++++++++++++++-------------------
 1 file changed, 19 insertions(+), 19 deletions(-)

diff --git a/kernel/sched/cpudeadline.c b/kernel/sched/cpudeadline.c
index d418449..3c42702 100644
--- a/kernel/sched/cpudeadline.c
+++ b/kernel/sched/cpudeadline.c
@@ -41,7 +41,7 @@ static void cpudl_exchange(struct cpudl *cp, int a, int b)
        swap(cp->elements[cpu_a].idx, cp->elements[cpu_b].idx);
 }
 
-static void cpudl_heapify(struct cpudl *cp, int idx)
+static void cpudl_heapify_down(struct cpudl *cp, int idx)
 {
        int l, r, largest;
 
@@ -66,20 +66,25 @@ static void cpudl_heapify(struct cpudl *cp, int idx)
        }
 }
 
+static void cpudl_heapify_up(struct cpudl *cp, int idx)
+{
+       while (idx > 0 && dl_time_before(cp->elements[parent(idx)].dl,
+                       cp->elements[idx].dl)) {
+               cpudl_exchange(cp, idx, parent(idx));
+               idx = parent(idx);
+       }
+}
+
 static void cpudl_change_key(struct cpudl *cp, int idx, u64 new_dl)
 {
        WARN_ON(idx == IDX_INVALID || !cpu_present(idx));
 
        if (dl_time_before(new_dl, cp->elements[idx].dl)) {
                cp->elements[idx].dl = new_dl;
-               cpudl_heapify(cp, idx);
+               cpudl_heapify_down(cp, idx);
        } else {
                cp->elements[idx].dl = new_dl;
-               while (idx > 0 && dl_time_before(cp->elements[parent(idx)].dl,
-                                       cp->elements[idx].dl)) {
-                       cpudl_exchange(cp, idx, parent(idx));
-                       idx = parent(idx);
-               }
+               cpudl_heapify_up(cp, idx);
        }
 }
 
@@ -154,24 +159,19 @@ void cpudl_set(struct cpudl *cp, int cpu, u64 dl, int 
is_valid)
                cp->size--;
                cp->elements[new_cpu].idx = old_idx;
                cp->elements[cpu].idx = IDX_INVALID;
-               while (old_idx > 0 && dl_time_before(
-                               cp->elements[parent(old_idx)].dl,
-                               cp->elements[old_idx].dl)) {
-                       cpudl_exchange(cp, old_idx, parent(old_idx));
-                       old_idx = parent(old_idx);
-               }
+               cpudl_heapify_up(cp, old_idx);
                cpumask_set_cpu(cpu, cp->free_cpus);
-                cpudl_heapify(cp, old_idx);
+                cpudl_heapify_down(cp, old_idx);
 
                goto out;
        }
 
        if (old_idx == IDX_INVALID) {
-               cp->size++;
-               cp->elements[cp->size - 1].dl = dl;
-               cp->elements[cp->size - 1].cpu = cpu;
-               cp->elements[cpu].idx = cp->size - 1;
-               cpudl_change_key(cp, cp->size - 1, dl);
+               int size1 = cp->size++;
+               cp->elements[size1].dl = dl;
+               cp->elements[size1].cpu = cpu;
+               cp->elements[cpu].idx = size1;
+               cpudl_heapify_up(cp, size1);
                cpumask_clear_cpu(cpu, cp->free_cpus);
        } else {
                cpudl_change_key(cp, old_idx, dl);
-- 
2.7.4