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Subject[PATCH V3] sched: fix autogroup nice tune on UP
On Mon, Jan 24, 2011 at 08:18:11AM +0200, Pekka Enberg wrote:
> I proposed extracting the shares calculation logic in
> update_cfs_shares() to reduce code duplication for the SMP and UP
> patch. So something like this:

Thanks for your example.
So something like this?

---
From: Yong Zhang <yong.zhang0@gmail.com>
Subject: [PATCH V3] sched: fix autogroup nice tune on UP
When on UP with FAIR_GROUP_SCHED enabled, tune shares
only affect tg->shares, but is not reflected on
tg->se->load, the reason is update_cfs_shares()
do nothing on UP.
So introduce update_cfs_shares() for UP && FAIR_GROUP_SCHED.

This issue is found when enable autogroup, but also
exists on cgroup.cpu on UP.

Signed-off-by: Yong Zhang <yong.zhang0@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mike Galbraith <efault@gmx.de>
---
Changelog from V2:
Move share caculation to calc_cfs_shares(), thus save
some duplicated code for update_cfs_shares().
Idea from Pekka Enberg.

kernel/sched_fair.c | 78 ++++++++++++++++++++++++++++++++++----------------
1 files changed, 53 insertions(+), 25 deletions(-)
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 77e9166..3547699 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -699,7 +699,8 @@ account_entity_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se)
cfs_rq->nr_running--;
}

-#if defined CONFIG_SMP && defined CONFIG_FAIR_GROUP_SCHED
+#ifdef CONFIG_FAIR_GROUP_SCHED
+# ifdef CONFIG_SMP
static void update_cfs_rq_load_contribution(struct cfs_rq *cfs_rq,
int global_update)
{
@@ -762,6 +763,51 @@ static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update)
list_del_leaf_cfs_rq(cfs_rq);
}

+static long calc_cfs_shares(struct cfs_rq *cfs_rq, struct task_group *tg,
+ long weight_delta)
+{
+ long load_weight, load, shares;
+
+ load = cfs_rq->load.weight + weight_delta;
+
+ load_weight = atomic_read(&tg->load_weight);
+ load_weight -= cfs_rq->load_contribution;
+ load_weight += load;
+
+ shares = (tg->shares * load);
+ if (load_weight)
+ shares /= load_weight;
+
+ if (shares < MIN_SHARES)
+ shares = MIN_SHARES;
+ if (shares > tg->shares)
+ shares = tg->shares;
+
+ return shares;
+}
+
+static void update_entity_shares_tick(struct cfs_rq *cfs_rq)
+{
+ if (cfs_rq->load_unacc_exec_time > sysctl_sched_shares_window) {
+ update_cfs_load(cfs_rq, 0);
+ update_cfs_shares(cfs_rq, 0);
+ }
+}
+# else /* CONFIG_SMP */
+static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update)
+{
+}
+
+static inline long calc_cfs_shares(struct cfs_rq *cfs_rq, struct task_group *tg,
+ long weight_delta)
+{
+ return tg->shares;
+}
+
+static inline void update_entity_shares_tick(struct cfs_rq *cfs_rq)
+{
+}
+# endif /* CONFIG_SMP */
static void reweight_entity(struct cfs_rq *cfs_rq, struct sched_entity *se,
unsigned long weight)
{
@@ -782,7 +828,7 @@ static void update_cfs_shares(struct cfs_rq *cfs_rq, long weight_delta)
{
struct task_group *tg;
struct sched_entity *se;
- long load_weight, load, shares;
+ long shares;

if (!cfs_rq)
return;
@@ -791,32 +837,14 @@ static void update_cfs_shares(struct cfs_rq *cfs_rq, long weight_delta)
se = tg->se[cpu_of(rq_of(cfs_rq))];
if (!se)
return;
-
- load = cfs_rq->load.weight + weight_delta;
-
- load_weight = atomic_read(&tg->load_weight);
- load_weight -= cfs_rq->load_contribution;
- load_weight += load;
-
- shares = (tg->shares * load);
- if (load_weight)
- shares /= load_weight;
-
- if (shares < MIN_SHARES)
- shares = MIN_SHARES;
- if (shares > tg->shares)
- shares = tg->shares;
+#ifndef CONFIG_SMP
+ if (likely(se->load.weight == tg->shares))
+ return;
+#endif
+ shares = calc_cfs_shares(cfs_rq, tg, weight_delta);

reweight_entity(cfs_rq_of(se), se, shares);
}
-
-static void update_entity_shares_tick(struct cfs_rq *cfs_rq)
-{
- if (cfs_rq->load_unacc_exec_time > sysctl_sched_shares_window) {
- update_cfs_load(cfs_rq, 0);
- update_cfs_shares(cfs_rq, 0);
- }
-}
#else /* CONFIG_FAIR_GROUP_SCHED */
static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update)
{
--
1.7.0.4


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