* [RESEND PATCH v2 1/2] sched/deadline: Add cpudl_maximum_dl() for clean-up
@ 2017-10-10 6:44 Byungchul Park
2017-10-10 6:44 ` [RESEND PATCH v2 2/2] sched/deadline: Initialize cp->elements[].cpu to an invalid value Byungchul Park
` (2 more replies)
0 siblings, 3 replies; 9+ messages in thread
From: Byungchul Park @ 2017-10-10 6:44 UTC (permalink / raw)
To: peterz, mingo, rostedt; +Cc: linux-kernel, juri.lelli, kernel-team
Changes from v1
- Enhance commit msg
- Prevent WARN in cpumask_test_cpu() in cpudl_find() when best_cpu == -1
-----8<-----
>From 7735382d07ae6a61d740ae39ba2ecf169d43b8a2 Mon Sep 17 00:00:00 2001
From: Byungchul Park <byungchul.park@lge.com>
Date: Wed, 22 Mar 2017 14:25:56 +0900
Subject: [RESEND PATCH v2 1/2] sched/deadline: Add cpudl_maximum_dl() for clean-up
Current code uses cpudl_maximum() to get the root node's cpu, while it
directly accesses the root node like 'cp->elements[0].dl' to get the
root node's dl. It would be more readible to add a function for the dl,
as well. Added it.
Signed-off-by: Byungchul Park <byungchul.park@lge.com>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
kernel/sched/cpudeadline.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/kernel/sched/cpudeadline.c b/kernel/sched/cpudeadline.c
index 8d9562d..9f02035 100644
--- a/kernel/sched/cpudeadline.c
+++ b/kernel/sched/cpudeadline.c
@@ -108,11 +108,16 @@ static void cpudl_heapify(struct cpudl *cp, int idx)
cpudl_heapify_down(cp, idx);
}
-static inline int cpudl_maximum(struct cpudl *cp)
+static inline int cpudl_maximum_cpu(struct cpudl *cp)
{
return cp->elements[0].cpu;
}
+static inline u64 cpudl_maximum_dl(struct cpudl *cp)
+{
+ return cp->elements[0].dl;
+}
+
/*
* cpudl_find - find the best (later-dl) CPU in the system
* @cp: the cpudl max-heap context
@@ -130,11 +135,11 @@ int cpudl_find(struct cpudl *cp, struct task_struct *p,
cpumask_and(later_mask, cp->free_cpus, &p->cpus_allowed)) {
return 1;
} else {
- int best_cpu = cpudl_maximum(cp);
+ int best_cpu = cpudl_maximum_cpu(cp);
WARN_ON(best_cpu != -1 && !cpu_present(best_cpu));
if (cpumask_test_cpu(best_cpu, &p->cpus_allowed) &&
- dl_time_before(dl_se->deadline, cp->elements[0].dl)) {
+ dl_time_before(dl_se->deadline, cpudl_maximum_dl(cp))) {
if (later_mask)
cpumask_set_cpu(best_cpu, later_mask);
--
1.9.1
^ permalink raw reply related [flat|nested] 9+ messages in thread* [RESEND PATCH v2 2/2] sched/deadline: Initialize cp->elements[].cpu to an invalid value
2017-10-10 6:44 [RESEND PATCH v2 1/2] sched/deadline: Add cpudl_maximum_dl() for clean-up Byungchul Park
@ 2017-10-10 6:44 ` Byungchul Park
2017-10-12 7:57 ` Byungchul Park
2017-10-23 8:43 ` [RESEND PATCH v2 1/2] sched/deadline: Add cpudl_maximum_dl() for clean-up Byungchul Park
2017-10-27 8:38 ` Byungchul Park
2 siblings, 1 reply; 9+ messages in thread
From: Byungchul Park @ 2017-10-10 6:44 UTC (permalink / raw)
To: peterz, mingo, rostedt; +Cc: linux-kernel, juri.lelli, kernel-team
Currently, migrating tasks to cpu0 unconditionally happens when the
heap is empty, since cp->elements[].cpu was initialized to 0(=cpu0).
We have to distinguish between the empty case and cpu0 to avoid the
unnecessary migrantions. Therefore, it has to return an invalid value
e.i. -1 in that case.
Signed-off-by: Byungchul Park <byungchul.park@lge.com>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
kernel/sched/cpudeadline.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/kernel/sched/cpudeadline.c b/kernel/sched/cpudeadline.c
index 9f02035..bcf903f 100644
--- a/kernel/sched/cpudeadline.c
+++ b/kernel/sched/cpudeadline.c
@@ -138,6 +138,12 @@ int cpudl_find(struct cpudl *cp, struct task_struct *p,
int best_cpu = cpudl_maximum_cpu(cp);
WARN_ON(best_cpu != -1 && !cpu_present(best_cpu));
+ /*
+ * The heap tree is empry for now, just return.
+ */
+ if (best_cpu == -1)
+ return 0;
+
if (cpumask_test_cpu(best_cpu, &p->cpus_allowed) &&
dl_time_before(dl_se->deadline, cpudl_maximum_dl(cp))) {
if (later_mask)
@@ -265,8 +271,10 @@ int cpudl_init(struct cpudl *cp)
return -ENOMEM;
}
- for_each_possible_cpu(i)
+ for_each_possible_cpu(i) {
+ cp->elements[i].cpu = -1;
cp->elements[i].idx = IDX_INVALID;
+ }
return 0;
}
--
1.9.1
^ permalink raw reply related [flat|nested] 9+ messages in thread* Re: [RESEND PATCH v2 2/2] sched/deadline: Initialize cp->elements[].cpu to an invalid value
2017-10-10 6:44 ` [RESEND PATCH v2 2/2] sched/deadline: Initialize cp->elements[].cpu to an invalid value Byungchul Park
@ 2017-10-12 7:57 ` Byungchul Park
2017-11-13 12:46 ` Daniel Bristot de Oliveira
0 siblings, 1 reply; 9+ messages in thread
From: Byungchul Park @ 2017-10-12 7:57 UTC (permalink / raw)
To: peterz, mingo, rostedt; +Cc: linux-kernel, juri.lelli, kernel-team
On Tue, Oct 10, 2017 at 03:44:04PM +0900, Byungchul Park wrote:
> Currently, migrating tasks to cpu0 unconditionally happens when the
> heap is empty, since cp->elements[].cpu was initialized to 0(=cpu0).
> We have to distinguish between the empty case and cpu0 to avoid the
> unnecessary migrantions. Therefore, it has to return an invalid value
> e.i. -1 in that case.
This patch does what it should obviously do. Could you check this?
> Signed-off-by: Byungchul Park <byungchul.park@lge.com>
> Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> ---
> kernel/sched/cpudeadline.c | 10 +++++++++-
> 1 file changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/sched/cpudeadline.c b/kernel/sched/cpudeadline.c
> index 9f02035..bcf903f 100644
> --- a/kernel/sched/cpudeadline.c
> +++ b/kernel/sched/cpudeadline.c
> @@ -138,6 +138,12 @@ int cpudl_find(struct cpudl *cp, struct task_struct *p,
> int best_cpu = cpudl_maximum_cpu(cp);
> WARN_ON(best_cpu != -1 && !cpu_present(best_cpu));
>
> + /*
> + * The heap tree is empry for now, just return.
> + */
> + if (best_cpu == -1)
> + return 0;
> +
> if (cpumask_test_cpu(best_cpu, &p->cpus_allowed) &&
> dl_time_before(dl_se->deadline, cpudl_maximum_dl(cp))) {
> if (later_mask)
> @@ -265,8 +271,10 @@ int cpudl_init(struct cpudl *cp)
> return -ENOMEM;
> }
>
> - for_each_possible_cpu(i)
> + for_each_possible_cpu(i) {
> + cp->elements[i].cpu = -1;
> cp->elements[i].idx = IDX_INVALID;
> + }
>
> return 0;
> }
> --
> 1.9.1
^ permalink raw reply [flat|nested] 9+ messages in thread* Re: [RESEND PATCH v2 2/2] sched/deadline: Initialize cp->elements[].cpu to an invalid value
2017-10-12 7:57 ` Byungchul Park
@ 2017-11-13 12:46 ` Daniel Bristot de Oliveira
2017-11-13 23:30 ` Byungchul Park
0 siblings, 1 reply; 9+ messages in thread
From: Daniel Bristot de Oliveira @ 2017-11-13 12:46 UTC (permalink / raw)
To: Byungchul Park, peterz, mingo, rostedt
Cc: linux-kernel, juri.lelli, kernel-team
On 10/12/2017 09:57 AM, Byungchul Park wrote:
> On Tue, Oct 10, 2017 at 03:44:04PM +0900, Byungchul Park wrote:
>> Currently, migrating tasks to cpu0 unconditionally happens when the
>> heap is empty, since cp->elements[].cpu was initialized to 0(=cpu0).
>> We have to distinguish between the empty case and cpu0 to avoid the
>> unnecessary migrantions. Therefore, it has to return an invalid value
s/migrantions/migrations/ ?
>> e.i. -1 in that case.
>
> This patch does what it should obviously do. Could you check this?
>
>> Signed-off-by: Byungchul Park <byungchul.park@lge.com>
>> Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
>> ---
>> kernel/sched/cpudeadline.c | 10 +++++++++-
>> 1 file changed, 9 insertions(+), 1 deletion(-)
>>
>> diff --git a/kernel/sched/cpudeadline.c b/kernel/sched/cpudeadline.c
>> index 9f02035..bcf903f 100644
>> --- a/kernel/sched/cpudeadline.c
>> +++ b/kernel/sched/cpudeadline.c
>> @@ -138,6 +138,12 @@ int cpudl_find(struct cpudl *cp, struct task_struct *p,
>> int best_cpu = cpudl_maximum_cpu(cp);
>> WARN_ON(best_cpu != -1 && !cpu_present(best_cpu));
>>
>> + /*
>> + * The heap tree is empry for now, just return.
s/empry/empty/ ?
>> + */
>> + if (best_cpu == -1)
>> + return 0;
>> +
>> if (cpumask_test_cpu(best_cpu, &p->cpus_allowed) &&
>> dl_time_before(dl_se->deadline, cpudl_maximum_dl(cp))) {
>> if (later_mask)
>> @@ -265,8 +271,10 @@ int cpudl_init(struct cpudl *cp)
>> return -ENOMEM;
>> }
>>
>> - for_each_possible_cpu(i)
>> + for_each_possible_cpu(i) {
>> + cp->elements[i].cpu = -1;
>> cp->elements[i].idx = IDX_INVALID;
>> + }
>>
>> return 0;
>> }
>> --
>> 1.9.1
^ permalink raw reply [flat|nested] 9+ messages in thread* Re: [RESEND PATCH v2 2/2] sched/deadline: Initialize cp->elements[].cpu to an invalid value
2017-11-13 12:46 ` Daniel Bristot de Oliveira
@ 2017-11-13 23:30 ` Byungchul Park
0 siblings, 0 replies; 9+ messages in thread
From: Byungchul Park @ 2017-11-13 23:30 UTC (permalink / raw)
To: Daniel Bristot de Oliveira, peterz, mingo, rostedt
Cc: linux-kernel, juri.lelli, kernel-team
On 11/13/2017 9:46 PM, Daniel Bristot de Oliveira wrote:
> On 10/12/2017 09:57 AM, Byungchul Park wrote:
>> On Tue, Oct 10, 2017 at 03:44:04PM +0900, Byungchul Park wrote:
>>> Currently, migrating tasks to cpu0 unconditionally happens when the
>>> heap is empty, since cp->elements[].cpu was initialized to 0(=cpu0).
>>> We have to distinguish between the empty case and cpu0 to avoid the
>>> unnecessary migrantions. Therefore, it has to return an invalid value
>
> s/migrantions/migrations/ ?
>
>>> e.i. -1 in that case.
>>
>> This patch does what it should obviously do. Could you check this?
>>
>>> Signed-off-by: Byungchul Park <byungchul.park@lge.com>
>>> Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
>>> ---
>>> kernel/sched/cpudeadline.c | 10 +++++++++-
>>> 1 file changed, 9 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/kernel/sched/cpudeadline.c b/kernel/sched/cpudeadline.c
>>> index 9f02035..bcf903f 100644
>>> --- a/kernel/sched/cpudeadline.c
>>> +++ b/kernel/sched/cpudeadline.c
>>> @@ -138,6 +138,12 @@ int cpudl_find(struct cpudl *cp, struct task_struct *p,
>>> int best_cpu = cpudl_maximum_cpu(cp);
>>> WARN_ON(best_cpu != -1 && !cpu_present(best_cpu));
>>>
>>> + /*
>>> + * The heap tree is empry for now, just return.
>
> s/empry/empty/ ?
Hello Daniel,
Thank you very much for pointing out typos.
I shall do spellcheck evetytime submiting patches from now on.
--
Thanks,
Byungchul
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [RESEND PATCH v2 1/2] sched/deadline: Add cpudl_maximum_dl() for clean-up
2017-10-10 6:44 [RESEND PATCH v2 1/2] sched/deadline: Add cpudl_maximum_dl() for clean-up Byungchul Park
2017-10-10 6:44 ` [RESEND PATCH v2 2/2] sched/deadline: Initialize cp->elements[].cpu to an invalid value Byungchul Park
@ 2017-10-23 8:43 ` Byungchul Park
2017-10-27 8:38 ` Byungchul Park
2 siblings, 0 replies; 9+ messages in thread
From: Byungchul Park @ 2017-10-23 8:43 UTC (permalink / raw)
To: peterz, mingo, rostedt; +Cc: linux-kernel, juri.lelli, kernel-team
On Tue, Oct 10, 2017 at 03:44:03PM +0900, Byungchul Park wrote:
> Changes from v1
> - Enhance commit msg
> - Prevent WARN in cpumask_test_cpu() in cpudl_find() when best_cpu == -1
>
> -----8<-----
> >From 7735382d07ae6a61d740ae39ba2ecf169d43b8a2 Mon Sep 17 00:00:00 2001
> From: Byungchul Park <byungchul.park@lge.com>
> Date: Wed, 22 Mar 2017 14:25:56 +0900
> Subject: [RESEND PATCH v2 1/2] sched/deadline: Add cpudl_maximum_dl() for clean-up
>
> Current code uses cpudl_maximum() to get the root node's cpu, while it
> directly accesses the root node like 'cp->elements[0].dl' to get the
> root node's dl. It would be more readible to add a function for the dl,
> as well. Added it.
Is there any opinion about this patch? If no, could you consider this?
>
> Signed-off-by: Byungchul Park <byungchul.park@lge.com>
> Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> ---
> kernel/sched/cpudeadline.c | 11 ++++++++---
> 1 file changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/kernel/sched/cpudeadline.c b/kernel/sched/cpudeadline.c
> index 8d9562d..9f02035 100644
> --- a/kernel/sched/cpudeadline.c
> +++ b/kernel/sched/cpudeadline.c
> @@ -108,11 +108,16 @@ static void cpudl_heapify(struct cpudl *cp, int idx)
> cpudl_heapify_down(cp, idx);
> }
>
> -static inline int cpudl_maximum(struct cpudl *cp)
> +static inline int cpudl_maximum_cpu(struct cpudl *cp)
> {
> return cp->elements[0].cpu;
> }
>
> +static inline u64 cpudl_maximum_dl(struct cpudl *cp)
> +{
> + return cp->elements[0].dl;
> +}
> +
> /*
> * cpudl_find - find the best (later-dl) CPU in the system
> * @cp: the cpudl max-heap context
> @@ -130,11 +135,11 @@ int cpudl_find(struct cpudl *cp, struct task_struct *p,
> cpumask_and(later_mask, cp->free_cpus, &p->cpus_allowed)) {
> return 1;
> } else {
> - int best_cpu = cpudl_maximum(cp);
> + int best_cpu = cpudl_maximum_cpu(cp);
> WARN_ON(best_cpu != -1 && !cpu_present(best_cpu));
>
> if (cpumask_test_cpu(best_cpu, &p->cpus_allowed) &&
> - dl_time_before(dl_se->deadline, cp->elements[0].dl)) {
> + dl_time_before(dl_se->deadline, cpudl_maximum_dl(cp))) {
> if (later_mask)
> cpumask_set_cpu(best_cpu, later_mask);
>
> --
> 1.9.1
^ permalink raw reply [flat|nested] 9+ messages in thread* Re: [RESEND PATCH v2 1/2] sched/deadline: Add cpudl_maximum_dl() for clean-up
2017-10-10 6:44 [RESEND PATCH v2 1/2] sched/deadline: Add cpudl_maximum_dl() for clean-up Byungchul Park
2017-10-10 6:44 ` [RESEND PATCH v2 2/2] sched/deadline: Initialize cp->elements[].cpu to an invalid value Byungchul Park
2017-10-23 8:43 ` [RESEND PATCH v2 1/2] sched/deadline: Add cpudl_maximum_dl() for clean-up Byungchul Park
@ 2017-10-27 8:38 ` Byungchul Park
2017-11-13 11:00 ` Daniel Bristot de Oliveira
2 siblings, 1 reply; 9+ messages in thread
From: Byungchul Park @ 2017-10-27 8:38 UTC (permalink / raw)
To: peterz, mingo, rostedt; +Cc: linux-kernel, juri.lelli, kernel-team
On Tue, Oct 10, 2017 at 03:44:03PM +0900, Byungchul Park wrote:
> Changes from v1
> - Enhance commit msg
> - Prevent WARN in cpumask_test_cpu() in cpudl_find() when best_cpu == -1
>
> -----8<-----
> >From 7735382d07ae6a61d740ae39ba2ecf169d43b8a2 Mon Sep 17 00:00:00 2001
> From: Byungchul Park <byungchul.park@lge.com>
> Date: Wed, 22 Mar 2017 14:25:56 +0900
> Subject: [RESEND PATCH v2 1/2] sched/deadline: Add cpudl_maximum_dl() for clean-up
>
> Current code uses cpudl_maximum() to get the root node's cpu, while it
> directly accesses the root node like 'cp->elements[0].dl' to get the
> root node's dl. It would be more readible to add a function for the dl,
> as well. Added it.
Hello everyone,
Could you tell opinions?
> Signed-off-by: Byungchul Park <byungchul.park@lge.com>
> Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> ---
> kernel/sched/cpudeadline.c | 11 ++++++++---
> 1 file changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/kernel/sched/cpudeadline.c b/kernel/sched/cpudeadline.c
> index 8d9562d..9f02035 100644
> --- a/kernel/sched/cpudeadline.c
> +++ b/kernel/sched/cpudeadline.c
> @@ -108,11 +108,16 @@ static void cpudl_heapify(struct cpudl *cp, int idx)
> cpudl_heapify_down(cp, idx);
> }
>
> -static inline int cpudl_maximum(struct cpudl *cp)
> +static inline int cpudl_maximum_cpu(struct cpudl *cp)
> {
> return cp->elements[0].cpu;
> }
>
> +static inline u64 cpudl_maximum_dl(struct cpudl *cp)
> +{
> + return cp->elements[0].dl;
> +}
> +
> /*
> * cpudl_find - find the best (later-dl) CPU in the system
> * @cp: the cpudl max-heap context
> @@ -130,11 +135,11 @@ int cpudl_find(struct cpudl *cp, struct task_struct *p,
> cpumask_and(later_mask, cp->free_cpus, &p->cpus_allowed)) {
> return 1;
> } else {
> - int best_cpu = cpudl_maximum(cp);
> + int best_cpu = cpudl_maximum_cpu(cp);
> WARN_ON(best_cpu != -1 && !cpu_present(best_cpu));
>
> if (cpumask_test_cpu(best_cpu, &p->cpus_allowed) &&
> - dl_time_before(dl_se->deadline, cp->elements[0].dl)) {
> + dl_time_before(dl_se->deadline, cpudl_maximum_dl(cp))) {
> if (later_mask)
> cpumask_set_cpu(best_cpu, later_mask);
>
> --
> 1.9.1
^ permalink raw reply [flat|nested] 9+ messages in thread* Re: [RESEND PATCH v2 1/2] sched/deadline: Add cpudl_maximum_dl() for clean-up
2017-10-27 8:38 ` Byungchul Park
@ 2017-11-13 11:00 ` Daniel Bristot de Oliveira
0 siblings, 0 replies; 9+ messages in thread
From: Daniel Bristot de Oliveira @ 2017-11-13 11:00 UTC (permalink / raw)
To: Byungchul Park, peterz, mingo, rostedt
Cc: linux-kernel, juri.lelli, kernel-team
On 10/27/2017 10:38 AM, Byungchul Park wrote:
> On Tue, Oct 10, 2017 at 03:44:03PM +0900, Byungchul Park wrote:
>> Changes from v1
>> - Enhance commit msg
>> - Prevent WARN in cpumask_test_cpu() in cpudl_find() when best_cpu == -1
>>
>> -----8<-----
>> >From 7735382d07ae6a61d740ae39ba2ecf169d43b8a2 Mon Sep 17 00:00:00 2001
>> From: Byungchul Park <byungchul.park@lge.com>
>> Date: Wed, 22 Mar 2017 14:25:56 +0900
>> Subject: [RESEND PATCH v2 1/2] sched/deadline: Add cpudl_maximum_dl() for clean-up
>>
>> Current code uses cpudl_maximum() to get the root node's cpu, while it
>> directly accesses the root node like 'cp->elements[0].dl' to get the
>> root node's dl. It would be more readible to add a function for the dl,
>> as well. Added it.
>
> Hello everyone,
>
> Could you tell opinions?
>
>> Signed-off-by: Byungchul Park <byungchul.park@lge.com>
>> Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: Daniel Bristot de Oliveira <bristot@redhat.com>
>> ---
>> kernel/sched/cpudeadline.c | 11 ++++++++---
>> 1 file changed, 8 insertions(+), 3 deletions(-)
>>
>> diff --git a/kernel/sched/cpudeadline.c b/kernel/sched/cpudeadline.c
>> index 8d9562d..9f02035 100644
>> --- a/kernel/sched/cpudeadline.c
>> +++ b/kernel/sched/cpudeadline.c
>> @@ -108,11 +108,16 @@ static void cpudl_heapify(struct cpudl *cp, int idx)
>> cpudl_heapify_down(cp, idx);
>> }
>>
>> -static inline int cpudl_maximum(struct cpudl *cp)
>> +static inline int cpudl_maximum_cpu(struct cpudl *cp)
>> {
>> return cp->elements[0].cpu;
>> }
>>
>> +static inline u64 cpudl_maximum_dl(struct cpudl *cp)
>> +{
>> + return cp->elements[0].dl;
>> +}
>> +
>> /*
>> * cpudl_find - find the best (later-dl) CPU in the system
>> * @cp: the cpudl max-heap context
>> @@ -130,11 +135,11 @@ int cpudl_find(struct cpudl *cp, struct task_struct *p,
>> cpumask_and(later_mask, cp->free_cpus, &p->cpus_allowed)) {
>> return 1;
>> } else {
>> - int best_cpu = cpudl_maximum(cp);
>> + int best_cpu = cpudl_maximum_cpu(cp);
>> WARN_ON(best_cpu != -1 && !cpu_present(best_cpu));
>>
>> if (cpumask_test_cpu(best_cpu, &p->cpus_allowed) &&
>> - dl_time_before(dl_se->deadline, cp->elements[0].dl)) {
>> + dl_time_before(dl_se->deadline, cpudl_maximum_dl(cp))) {
>> if (later_mask)
>> cpumask_set_cpu(best_cpu, later_mask);
>>
>> --
>> 1.9.1
^ permalink raw reply [flat|nested] 9+ messages in thread
* [RESEND PATCH v2 1/2] sched/deadline: Add cpudl_maximum_dl() for clean-up
@ 2017-11-02 1:25 Byungchul Park
2017-11-02 1:25 ` [RESEND PATCH v2 2/2] sched/deadline: Initialize cp->elements[].cpu to an invalid value Byungchul Park
0 siblings, 1 reply; 9+ messages in thread
From: Byungchul Park @ 2017-11-02 1:25 UTC (permalink / raw)
To: peterz, mingo, rostedt
Cc: tglx, raistlin, linux-kernel, juri.lelli, kernel-team
Changes from v1
- Enhance commit msg
- Prevent WARN in cpumask_test_cpu() in cpudl_find() when best_cpu == -1
-----8<-----
>From 7735382d07ae6a61d740ae39ba2ecf169d43b8a2 Mon Sep 17 00:00:00 2001
From: Byungchul Park <byungchul.park@lge.com>
Date: Wed, 22 Mar 2017 14:25:56 +0900
Subject: [RESEND PATCH v2 1/2] sched/deadline: Add cpudl_maximum_dl() for clean-up
Current code uses cpudl_maximum() to get the root node's cpu, while it
directly accesses the root node like 'cp->elements[0].dl' to get the
root node's dl. It would be more readible to add a function for the dl,
as well. Added it.
Signed-off-by: Byungchul Park <byungchul.park@lge.com>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
kernel/sched/cpudeadline.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/kernel/sched/cpudeadline.c b/kernel/sched/cpudeadline.c
index 8d9562d..9f02035 100644
--- a/kernel/sched/cpudeadline.c
+++ b/kernel/sched/cpudeadline.c
@@ -108,11 +108,16 @@ static void cpudl_heapify(struct cpudl *cp, int idx)
cpudl_heapify_down(cp, idx);
}
-static inline int cpudl_maximum(struct cpudl *cp)
+static inline int cpudl_maximum_cpu(struct cpudl *cp)
{
return cp->elements[0].cpu;
}
+static inline u64 cpudl_maximum_dl(struct cpudl *cp)
+{
+ return cp->elements[0].dl;
+}
+
/*
* cpudl_find - find the best (later-dl) CPU in the system
* @cp: the cpudl max-heap context
@@ -130,11 +135,11 @@ int cpudl_find(struct cpudl *cp, struct task_struct *p,
cpumask_and(later_mask, cp->free_cpus, &p->cpus_allowed)) {
return 1;
} else {
- int best_cpu = cpudl_maximum(cp);
+ int best_cpu = cpudl_maximum_cpu(cp);
WARN_ON(best_cpu != -1 && !cpu_present(best_cpu));
if (cpumask_test_cpu(best_cpu, &p->cpus_allowed) &&
- dl_time_before(dl_se->deadline, cp->elements[0].dl)) {
+ dl_time_before(dl_se->deadline, cpudl_maximum_dl(cp))) {
if (later_mask)
cpumask_set_cpu(best_cpu, later_mask);
--
1.9.1
^ permalink raw reply related [flat|nested] 9+ messages in thread* [RESEND PATCH v2 2/2] sched/deadline: Initialize cp->elements[].cpu to an invalid value
2017-11-02 1:25 Byungchul Park
@ 2017-11-02 1:25 ` Byungchul Park
0 siblings, 0 replies; 9+ messages in thread
From: Byungchul Park @ 2017-11-02 1:25 UTC (permalink / raw)
To: peterz, mingo, rostedt
Cc: tglx, raistlin, linux-kernel, juri.lelli, kernel-team
Currently, migrating tasks to cpu0 unconditionally happens when the
heap is empty, since cp->elements[].cpu was initialized to 0(=cpu0).
We have to distinguish between the empty case and cpu0 to avoid the
unnecessary migrantions. Therefore, it has to return an invalid value
e.i. -1 in that case.
Signed-off-by: Byungchul Park <byungchul.park@lge.com>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
kernel/sched/cpudeadline.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/kernel/sched/cpudeadline.c b/kernel/sched/cpudeadline.c
index 9f02035..bcf903f 100644
--- a/kernel/sched/cpudeadline.c
+++ b/kernel/sched/cpudeadline.c
@@ -138,6 +138,12 @@ int cpudl_find(struct cpudl *cp, struct task_struct *p,
int best_cpu = cpudl_maximum_cpu(cp);
WARN_ON(best_cpu != -1 && !cpu_present(best_cpu));
+ /*
+ * The heap tree is empry for now, just return.
+ */
+ if (best_cpu == -1)
+ return 0;
+
if (cpumask_test_cpu(best_cpu, &p->cpus_allowed) &&
dl_time_before(dl_se->deadline, cpudl_maximum_dl(cp))) {
if (later_mask)
@@ -265,8 +271,10 @@ int cpudl_init(struct cpudl *cp)
return -ENOMEM;
}
- for_each_possible_cpu(i)
+ for_each_possible_cpu(i) {
+ cp->elements[i].cpu = -1;
cp->elements[i].idx = IDX_INVALID;
+ }
return 0;
}
--
1.9.1
^ permalink raw reply related [flat|nested] 9+ messages in thread
end of thread, other threads:[~2017-11-13 23:30 UTC | newest]
Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-10-10 6:44 [RESEND PATCH v2 1/2] sched/deadline: Add cpudl_maximum_dl() for clean-up Byungchul Park
2017-10-10 6:44 ` [RESEND PATCH v2 2/2] sched/deadline: Initialize cp->elements[].cpu to an invalid value Byungchul Park
2017-10-12 7:57 ` Byungchul Park
2017-11-13 12:46 ` Daniel Bristot de Oliveira
2017-11-13 23:30 ` Byungchul Park
2017-10-23 8:43 ` [RESEND PATCH v2 1/2] sched/deadline: Add cpudl_maximum_dl() for clean-up Byungchul Park
2017-10-27 8:38 ` Byungchul Park
2017-11-13 11:00 ` Daniel Bristot de Oliveira
2017-11-02 1:25 Byungchul Park
2017-11-02 1:25 ` [RESEND PATCH v2 2/2] sched/deadline: Initialize cp->elements[].cpu to an invalid value Byungchul Park
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