scheduler fixes

GIT PULL Ingo Molnar 1 participant 1 message Jul 7, 2011 Scheduler

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Ingo Molnar

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2011-07-07 18:19 UTC #0 lore raw

Linus,

Please pull the latest sched-urgent-for-linus git tree from:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip.git sched-urgent-for-linus

Thanks,

Ingo

------------------>
Mike Galbraith (1):
sched, cgroups: Fix MIN_SHARES on 64-bit boxen

Peter Zijlstra (1):
sched: Disable (revert) SCHED_LOAD_SCALE increase

 include/linux/sched.h |    2 +-
 kernel/sched.c        |    9 +++------
 2 files changed, 4 insertions(+), 7 deletions(-)

include/linux/sched.h +1 -1

index a837b20..496770a 100644
@@ -808,7 +808,7 @@ enum cpu_idle_type {
  * when BITS_PER_LONG <= 32 are pretty high and the returns do not justify the
  * increased costs.
  */
-#if BITS_PER_LONG > 32
+#if 0 /* BITS_PER_LONG > 32 -- currently broken: it increases power usage under light load  */
 # define SCHED_LOAD_RESOLUTION	10
 # define scale_load(w)		((w) << SCHED_LOAD_RESOLUTION)
 # define scale_load_down(w)	((w) >> SCHED_LOAD_RESOLUTION)

kernel/sched.c +3 -6

index 3f2e502..9769c75 100644
@@ -292,8 +292,8 @@ static DEFINE_SPINLOCK(task_group_lock);
  * (The default weight is 1024 - so there's no practical
  *  limitation from this.)
  */
-#define MIN_SHARES	2
-#define MAX_SHARES	(1UL << (18 + SCHED_LOAD_RESOLUTION))
+#define MIN_SHARES	(1UL <<  1)
+#define MAX_SHARES	(1UL << 18)
 
 static int root_task_group_load = ROOT_TASK_GROUP_LOAD;
 #endif

@@ -8450,10 +8450,7 @@ int sched_group_set_shares(struct task_group *tg, unsigned long shares)
 	if (!tg->se[0])
 		return -EINVAL;
 
-	if (shares < MIN_SHARES)
-		shares = MIN_SHARES;
-	else if (shares > MAX_SHARES)
-		shares = MAX_SHARES;
+	shares = clamp(shares, scale_load(MIN_SHARES), scale_load(MAX_SHARES));
 
 	mutex_lock(&shares_mutex);
 	if (tg->shares == shares)