* Re: [PATCH] sched: Do not zero sg->cpumask and sg->sgp->power in build_sched_groups
2014-04-30 13:39 [PATCH] sched: Do not zero sg->cpumask and sg->sgp->power in build_sched_groups Dietmar Eggemann
@ 2014-04-30 13:46 ` Dietmar Eggemann
2014-05-13 8:32 ` Dietmar Eggemann
` (2 subsequent siblings)
3 siblings, 0 replies; 6+ messages in thread
From: Dietmar Eggemann @ 2014-04-30 13:46 UTC (permalink / raw)
To: Peter Zijlstra; +Cc: linux-kernel@vger.kernel.org
On 30/04/14 14:39, Dietmar Eggemann wrote:
> From: Dietmar Eggemann <Dietmar.Eggemann@arm.com>
>
> There is no need to zero struct sched_group member cpumask and struct
> sched_group_power member power since both structures are already allocated
> as zeroed memory in __sdt_alloc().
>
> This patch has been tested with
> BUG_ON(!cpumask_empty(sched_group_cpus(sg))); and BUG_ON(sg->sgp->power);
> in build_sched_groups() on ARM TC2 and INTEL i5 M520 platform including
> CPU hotplug scenarios.
>
> Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
> ---
> kernel/sched/core.c | 2 --
> 1 file changed, 2 deletions(-)
>
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index 9cae286824bb..6bc51aebbf1b 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -5807,8 +5807,6 @@ build_sched_groups(struct sched_domain *sd, int cpu)
> continue;
>
> group = get_group(i, sdd, &sg);
> - cpumask_clear(sched_group_cpus(sg));
> - sg->sgp->power = 0;
> cpumask_setall(sched_group_mask(sg));
>
> for_each_cpu(j, span) {
>
there is also a discrepancy between build_sched_groups() and
build_overlap_sched_groups(). The latter one sets power and power_orig
to SCHED_POWER_SCALE * cpumask_weight(sg_span) (since c3decf0dfbc95
'sched: Always initialize cpu-power' and 8e8339a3a1069 'sched:
Initialize power_orig for overlapping groups').
So we could do the same in build_sched_groups(). IMHO, then the
appropriate check 'if (!group->sgp->power_orig)' in
sched_domain_debug_one() becomes superfluous.
-- Dietmar
Patch proposal against tip_sched_core.
-- >8 --
Subject: [PATCH] sched: Initialize sg->sgp->power and sg->sgp->power_orig for
non-overlapping groups
---
kernel/sched/core.c | 17 +++--------------
1 file changed, 3 insertions(+), 14 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 9cae286824bb..ccf9b811ba37 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5206,18 +5206,6 @@ static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level,
break;
}
- /*
- * Even though we initialize ->power to something semi-sane,
- * we leave power_orig unset. This allows us to detect if
- * domain iteration is still funny without causing /0 traps.
- */
- if (!group->sgp->power_orig) {
- printk(KERN_CONT "\n");
- printk(KERN_ERR "ERROR: domain->cpu_power not "
- "set\n");
- break;
- }
-
if (!cpumask_weight(sched_group_cpus(group))) {
printk(KERN_CONT "\n");
printk(KERN_ERR "ERROR: empty group\n");
@@ -5807,8 +5795,6 @@ build_sched_groups(struct sched_domain *sd, int cpu)
continue;
group = get_group(i, sdd, &sg);
- cpumask_clear(sched_group_cpus(sg));
- sg->sgp->power = 0;
cpumask_setall(sched_group_mask(sg));
for_each_cpu(j, span) {
@@ -5819,6 +5805,9 @@ build_sched_groups(struct sched_domain *sd, int cpu)
cpumask_set_cpu(j, sched_group_cpus(sg));
}
+ sg->sgp->power = SCHED_POWER_SCALE * cpumask_weight(sched_group_cpus(sg));
+ sg->sgp->power_orig = sg->sgp->power;
+
if (!first)
first = sg;
if (last)
--
1.7.9.5
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH] sched: Do not zero sg->cpumask and sg->sgp->power in build_sched_groups
2014-04-30 13:39 [PATCH] sched: Do not zero sg->cpumask and sg->sgp->power in build_sched_groups Dietmar Eggemann
2014-04-30 13:46 ` Dietmar Eggemann
@ 2014-05-13 8:32 ` Dietmar Eggemann
2014-05-13 10:32 ` Peter Zijlstra
2014-05-19 13:09 ` [tip:sched/core] sched: Do not zero sg->cpumask and sg->sgp-> power " tip-bot for Dietmar Eggemann
2014-05-22 12:27 ` [tip:sched/core] sched: Do not zero sg->cpumask and sg->sgp-> power in build_sched_groups() tip-bot for Dietmar Eggemann
3 siblings, 1 reply; 6+ messages in thread
From: Dietmar Eggemann @ 2014-05-13 8:32 UTC (permalink / raw)
To: Peter Zijlstra; +Cc: linux-kernel@vger.kernel.org
Hi Peter,
On 30/04/14 14:39, Dietmar Eggemann wrote:
> From: Dietmar Eggemann <Dietmar.Eggemann@arm.com>
>
> There is no need to zero struct sched_group member cpumask and struct
> sched_group_power member power since both structures are already allocated
> as zeroed memory in __sdt_alloc().
>
> This patch has been tested with
> BUG_ON(!cpumask_empty(sched_group_cpus(sg))); and BUG_ON(sg->sgp->power);
> in build_sched_groups() on ARM TC2 and INTEL i5 M520 platform including
> CPU hotplug scenarios.
>
> Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
> ---
> kernel/sched/core.c | 2 --
> 1 file changed, 2 deletions(-)
>
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index 9cae286824bb..6bc51aebbf1b 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -5807,8 +5807,6 @@ build_sched_groups(struct sched_domain *sd, int cpu)
> continue;
>
> group = get_group(i, sdd, &sg);
> - cpumask_clear(sched_group_cpus(sg));
> - sg->sgp->power = 0;
> cpumask_setall(sched_group_mask(sg));
>
> for_each_cpu(j, span) {
>
I think this one slipped through the cracks. Could you have a look?
Thanks,
-- Dietmar
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] sched: Do not zero sg->cpumask and sg->sgp->power in build_sched_groups
2014-05-13 8:32 ` Dietmar Eggemann
@ 2014-05-13 10:32 ` Peter Zijlstra
0 siblings, 0 replies; 6+ messages in thread
From: Peter Zijlstra @ 2014-05-13 10:32 UTC (permalink / raw)
To: Dietmar Eggemann; +Cc: linux-kernel@vger.kernel.org
[-- Attachment #1: Type: text/plain, Size: 1430 bytes --]
On Tue, May 13, 2014 at 09:32:53AM +0100, Dietmar Eggemann wrote:
> Hi Peter,
>
> On 30/04/14 14:39, Dietmar Eggemann wrote:
> > From: Dietmar Eggemann <Dietmar.Eggemann@arm.com>
> >
> > There is no need to zero struct sched_group member cpumask and struct
> > sched_group_power member power since both structures are already allocated
> > as zeroed memory in __sdt_alloc().
> >
> > This patch has been tested with
> > BUG_ON(!cpumask_empty(sched_group_cpus(sg))); and BUG_ON(sg->sgp->power);
> > in build_sched_groups() on ARM TC2 and INTEL i5 M520 platform including
> > CPU hotplug scenarios.
> >
> > Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
> > ---
> > kernel/sched/core.c | 2 --
> > 1 file changed, 2 deletions(-)
> >
> > diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> > index 9cae286824bb..6bc51aebbf1b 100644
> > --- a/kernel/sched/core.c
> > +++ b/kernel/sched/core.c
> > @@ -5807,8 +5807,6 @@ build_sched_groups(struct sched_domain *sd, int cpu)
> > continue;
> >
> > group = get_group(i, sdd, &sg);
> > - cpumask_clear(sched_group_cpus(sg));
> > - sg->sgp->power = 0;
> > cpumask_setall(sched_group_mask(sg));
> >
> > for_each_cpu(j, span) {
> >
>
> I think this one slipped through the cracks. Could you have a look?
Yeah, got stuck in the backlog :/
Seems simple enough, queued it, we'll see if anything explodes ;-)
[-- Attachment #2: Type: application/pgp-signature, Size: 836 bytes --]
^ permalink raw reply [flat|nested] 6+ messages in thread
* [tip:sched/core] sched: Do not zero sg->cpumask and sg->sgp-> power in build_sched_groups
2014-04-30 13:39 [PATCH] sched: Do not zero sg->cpumask and sg->sgp->power in build_sched_groups Dietmar Eggemann
2014-04-30 13:46 ` Dietmar Eggemann
2014-05-13 8:32 ` Dietmar Eggemann
@ 2014-05-19 13:09 ` tip-bot for Dietmar Eggemann
2014-05-22 12:27 ` [tip:sched/core] sched: Do not zero sg->cpumask and sg->sgp-> power in build_sched_groups() tip-bot for Dietmar Eggemann
3 siblings, 0 replies; 6+ messages in thread
From: tip-bot for Dietmar Eggemann @ 2014-05-19 13:09 UTC (permalink / raw)
To: linux-tip-commits
Cc: linux-kernel, hpa, mingo, peterz, dietmar.eggemann,
Dietmar.Eggemann, tglx
Commit-ID: 4d65f453eb2c8f3dd9fc437c9a736c42ddbd50bd
Gitweb: http://git.kernel.org/tip/4d65f453eb2c8f3dd9fc437c9a736c42ddbd50bd
Author: Dietmar Eggemann <Dietmar.Eggemann@arm.com>
AuthorDate: Wed, 30 Apr 2014 14:39:38 +0100
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitDate: Mon, 19 May 2014 22:02:41 +0900
sched: Do not zero sg->cpumask and sg->sgp->power in build_sched_groups
There is no need to zero struct sched_group member cpumask and struct
sched_group_power member power since both structures are already allocated
as zeroed memory in __sdt_alloc().
This patch has been tested with
BUG_ON(!cpumask_empty(sched_group_cpus(sg))); and BUG_ON(sg->sgp->power);
in build_sched_groups() on ARM TC2 and INTEL i5 M520 platform including
CPU hotplug scenarios.
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1398865178-12577-1-git-send-email-dietmar.eggemann@arm.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
kernel/sched/core.c | 2 --
1 file changed, 2 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index ca76cc6..354cd5a 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5794,8 +5794,6 @@ build_sched_groups(struct sched_domain *sd, int cpu)
continue;
group = get_group(i, sdd, &sg);
- cpumask_clear(sched_group_cpus(sg));
- sg->sgp->power = 0;
cpumask_setall(sched_group_mask(sg));
for_each_cpu(j, span) {
^ permalink raw reply related [flat|nested] 6+ messages in thread* [tip:sched/core] sched: Do not zero sg->cpumask and sg->sgp-> power in build_sched_groups()
2014-04-30 13:39 [PATCH] sched: Do not zero sg->cpumask and sg->sgp->power in build_sched_groups Dietmar Eggemann
` (2 preceding siblings ...)
2014-05-19 13:09 ` [tip:sched/core] sched: Do not zero sg->cpumask and sg->sgp-> power " tip-bot for Dietmar Eggemann
@ 2014-05-22 12:27 ` tip-bot for Dietmar Eggemann
3 siblings, 0 replies; 6+ messages in thread
From: tip-bot for Dietmar Eggemann @ 2014-05-22 12:27 UTC (permalink / raw)
To: linux-tip-commits
Cc: linux-kernel, hpa, mingo, peterz, dietmar.eggemann,
Dietmar.Eggemann, tglx
Commit-ID: caffcdd8d27ba78730d5540396ce72ad022aff2c
Gitweb: http://git.kernel.org/tip/caffcdd8d27ba78730d5540396ce72ad022aff2c
Author: Dietmar Eggemann <Dietmar.Eggemann@arm.com>
AuthorDate: Wed, 30 Apr 2014 14:39:38 +0100
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Thu, 22 May 2014 11:16:30 +0200
sched: Do not zero sg->cpumask and sg->sgp->power in build_sched_groups()
There is no need to zero struct sched_group member cpumask and struct
sched_group_power member power since both structures are already allocated
as zeroed memory in __sdt_alloc().
This patch has been tested with
BUG_ON(!cpumask_empty(sched_group_cpus(sg))); and BUG_ON(sg->sgp->power);
in build_sched_groups() on ARM TC2 and INTEL i5 M520 platform including
CPU hotplug scenarios.
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1398865178-12577-1-git-send-email-dietmar.eggemann@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
kernel/sched/core.c | 2 --
1 file changed, 2 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 45d077e..6340c60 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5794,8 +5794,6 @@ build_sched_groups(struct sched_domain *sd, int cpu)
continue;
group = get_group(i, sdd, &sg);
- cpumask_clear(sched_group_cpus(sg));
- sg->sgp->power = 0;
cpumask_setall(sched_group_mask(sg));
for_each_cpu(j, span) {
^ permalink raw reply related [flat|nested] 6+ messages in thread