lkml.org 
[lkml]   [2009]   [Aug]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[tip:sched/core] sched: Fully integrate cpus_active_map and root-domain code
Commit-ID:  00aec93d10a051ea64f83eff75d4065a19508ea6
Gitweb: http://git.kernel.org/tip/00aec93d10a051ea64f83eff75d4065a19508ea6
Author: Gregory Haskins <ghaskins@novell.com>
AuthorDate: Thu, 30 Jul 2009 10:57:23 -0400
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Sun, 2 Aug 2009 14:26:12 +0200

sched: Fully integrate cpus_active_map and root-domain code

Reflect "active" cpus in the rq->rd->online field, instead of
the online_map.

The motivation is that things that use the root-domain code
(such as cpupri) only care about cpus classified as "active"
anyway. By synchronizing the root-domain state with the active
map, we allow several optimizations.

For instance, we can remove an extra cpumask_and from the
scheduler hotpath by utilizing rq->rd->online (since it is now
a cached version of cpu_active_map & rq->rd->span).

Signed-off-by: Gregory Haskins <ghaskins@novell.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Max Krasnyansky <maxk@qualcomm.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20090730145723.25226.24493.stgit@dev.haskins.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>


---
kernel/sched.c | 2 +-
kernel/sched_fair.c | 10 +++++++---
kernel/sched_rt.c | 7 -------
3 files changed, 8 insertions(+), 11 deletions(-)

diff --git a/kernel/sched.c b/kernel/sched.c
index 613fee5..475138c 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -7927,7 +7927,7 @@ static void rq_attach_root(struct rq *rq, struct root_domain *rd)
rq->rd = rd;

cpumask_set_cpu(rq->cpu, rd->span);
- if (cpumask_test_cpu(rq->cpu, cpu_online_mask))
+ if (cpumask_test_cpu(rq->cpu, cpu_active_mask))
set_rq_online(rq);

spin_unlock_irqrestore(&rq->lock, flags);
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 652e8bd..4934729 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -1046,17 +1046,21 @@ static void yield_task_fair(struct rq *rq)
* search starts with cpus closest then further out as needed,
* so we always favor a closer, idle cpu.
* Domains may include CPUs that are not usable for migration,
- * hence we need to mask them out (cpu_active_mask)
+ * hence we need to mask them out (rq->rd->online)
*
* Returns the CPU we should wake onto.
*/
#if defined(ARCH_HAS_SCHED_WAKE_IDLE)
+
+#define cpu_rd_active(cpu, rq) cpumask_test_cpu(cpu, rq->rd->online)
+
static int wake_idle(int cpu, struct task_struct *p)
{
struct sched_domain *sd;
int i;
unsigned int chosen_wakeup_cpu;
int this_cpu;
+ struct rq *task_rq = task_rq(p);

/*
* At POWERSAVINGS_BALANCE_WAKEUP level, if both this_cpu and prev_cpu
@@ -1089,10 +1093,10 @@ static int wake_idle(int cpu, struct task_struct *p)
for_each_domain(cpu, sd) {
if ((sd->flags & SD_WAKE_IDLE)
|| ((sd->flags & SD_WAKE_IDLE_FAR)
- && !task_hot(p, task_rq(p)->clock, sd))) {
+ && !task_hot(p, task_rq->clock, sd))) {
for_each_cpu_and(i, sched_domain_span(sd),
&p->cpus_allowed) {
- if (cpu_active(i) && idle_cpu(i)) {
+ if (cpu_rd_active(i, task_rq) && idle_cpu(i)) {
if (i != task_cpu(p)) {
schedstat_inc(p,
se.nr_wakeups_idle);
diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c
index a8f89bc..13f728e 100644
--- a/kernel/sched_rt.c
+++ b/kernel/sched_rt.c
@@ -1173,13 +1173,6 @@ static int find_lowest_rq(struct task_struct *task)
return -1; /* No targets found */

/*
- * Only consider CPUs that are usable for migration.
- * I guess we might want to change cpupri_find() to ignore those
- * in the first place.
- */
- cpumask_and(lowest_mask, lowest_mask, cpu_active_mask);
-
- /*
* At this point we have built a mask of cpus representing the
* lowest priority tasks in the system. Now we want to elect
* the best one based on our affinity and topology.

\
 
 \ /
  Last update: 2009-08-02 15:17    [W:0.047 / U:7.680 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site