2023-07-12 18:12:59

by Chen Yu

[permalink] [raw]
Subject: [PATCH] sched/topology: Align group flags when removing degenerate domain

The flags of the child of a given scheduling domain are used to initialize
the flags of its scheduling groups. When the child of a scheduling domain
is degenerated, the flags of its local scheduling group need to be updated
to align with the flags of its new child domain.

The flag SD_SHARE_CPUCAPACITY was aligned in
Commit bf2dc42d6beb ("sched/topology: Propagate SMT flags when removing degenerate domain").
Further generalize this alignment so other flags can be used later, such as
in cluster-based task wakeup. [1]

Link: https://lore.kernel.org/lkml/[email protected] #1
Suggested-by: Ricardo Neri <[email protected]>
Reported-by: Yicong Yang <[email protected]>
Closes: https://lore.kernel.org/lkml/[email protected]/
Signed-off-by: Chen Yu <[email protected]>
---
kernel/sched/topology.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index d3a3b2646ec4..ff02d7deec0c 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -722,8 +722,7 @@ cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu)

if (parent->parent) {
parent->parent->child = tmp;
- if (tmp->flags & SD_SHARE_CPUCAPACITY)
- parent->parent->groups->flags |= SD_SHARE_CPUCAPACITY;
+ parent->parent->groups->flags = tmp->flags;
}

/*
--
2.25.1



2023-07-12 19:01:35

by Tim Chen

[permalink] [raw]
Subject: Re: [PATCH] sched/topology: Align group flags when removing degenerate domain

On Thu, 2023-07-13 at 09:31 +0800, Chen Yu wrote:
> The flags of the child of a given scheduling domain are used to initialize
> the flags of its scheduling groups. When the child of a scheduling domain
> is degenerated, the flags of its local scheduling group need to be updated
> to align with the flags of its new child domain.
>
> The flag SD_SHARE_CPUCAPACITY was aligned in
> Commit bf2dc42d6beb ("sched/topology: Propagate SMT flags when removing degenerate domain").
> Further generalize this alignment so other flags can be used later, such as
> in cluster-based task wakeup. [1]
>
> Link: https://lore.kernel.org/lkml/[email protected] #1
> Suggested-by: Ricardo Neri <[email protected]>
> Reported-by: Yicong Yang <[email protected]>
> Closes: https://lore.kernel.org/lkml/[email protected]/
> Signed-off-by: Chen Yu <[email protected]>
> ---
> kernel/sched/topology.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
> index d3a3b2646ec4..ff02d7deec0c 100644
> --- a/kernel/sched/topology.c
> +++ b/kernel/sched/topology.c
> @@ -722,8 +722,7 @@ cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu)
>
> if (parent->parent) {
> parent->parent->child = tmp;
> - if (tmp->flags & SD_SHARE_CPUCAPACITY)
> - parent->parent->groups->flags |= SD_SHARE_CPUCAPACITY;
> + parent->parent->groups->flags = tmp->flags;
> }
>
> /*

Reviewed-by: Tim Chen <[email protected]>

2023-07-13 06:53:55

by Yicong Yang

[permalink] [raw]
Subject: Re: [PATCH] sched/topology: Align group flags when removing degenerate domain

On 2023/7/13 9:31, Chen Yu wrote:
> The flags of the child of a given scheduling domain are used to initialize
> the flags of its scheduling groups. When the child of a scheduling domain
> is degenerated, the flags of its local scheduling group need to be updated
> to align with the flags of its new child domain.
>
> The flag SD_SHARE_CPUCAPACITY was aligned in
> Commit bf2dc42d6beb ("sched/topology: Propagate SMT flags when removing degenerate domain").
> Further generalize this alignment so other flags can be used later, such as
> in cluster-based task wakeup. [1]

Currently I only update the cluster flags on my current testing branch. It'll be even better to
align all flags for possible usage. Will rebase on this one.

>
> Link: https://lore.kernel.org/lkml/[email protected] #1
> Suggested-by: Ricardo Neri <[email protected]>
> Reported-by: Yicong Yang <[email protected]>
> Closes: https://lore.kernel.org/lkml/[email protected]/
> Signed-off-by: Chen Yu <[email protected]>

Reviewed-by: Yicong Yang <[email protected]>

> ---
> kernel/sched/topology.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
> index d3a3b2646ec4..ff02d7deec0c 100644
> --- a/kernel/sched/topology.c
> +++ b/kernel/sched/topology.c
> @@ -722,8 +722,7 @@ cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu)
>
> if (parent->parent) {
> parent->parent->child = tmp;
> - if (tmp->flags & SD_SHARE_CPUCAPACITY)
> - parent->parent->groups->flags |= SD_SHARE_CPUCAPACITY;
> + parent->parent->groups->flags = tmp->flags;
> }
>
> /*
>

Subject: [tip: sched/core] sched/topology: Align group flags when removing degenerate domain

The following commit has been merged into the sched/core branch of tip:

Commit-ID: 4efcc8bc7e08c09c58a2f5cbc2096fbda5b7cf5e
Gitweb: https://git.kernel.org/tip/4efcc8bc7e08c09c58a2f5cbc2096fbda5b7cf5e
Author: Chen Yu <[email protected]>
AuthorDate: Thu, 13 Jul 2023 09:31:33 +08:00
Committer: Peter Zijlstra <[email protected]>
CommitterDate: Wed, 26 Jul 2023 12:28:51 +02:00

sched/topology: Align group flags when removing degenerate domain

The flags of the child of a given scheduling domain are used to initialize
the flags of its scheduling groups. When the child of a scheduling domain
is degenerated, the flags of its local scheduling group need to be updated
to align with the flags of its new child domain.

The flag SD_SHARE_CPUCAPACITY was aligned in
Commit bf2dc42d6beb ("sched/topology: Propagate SMT flags when removing degenerate domain").
Further generalize this alignment so other flags can be used later, such as
in cluster-based task wakeup. [1]

Reported-by: Yicong Yang <[email protected]>
Suggested-by: Ricardo Neri <[email protected]>
Signed-off-by: Chen Yu <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Reviewed-by: Tim Chen <[email protected]>
Reviewed-by: Yicong Yang <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
---
kernel/sched/topology.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index 7cfcfe5..05a5bc6 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -722,8 +722,7 @@ cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu)

if (parent->parent) {
parent->parent->child = tmp;
- if (tmp->flags & SD_SHARE_CPUCAPACITY)
- parent->parent->groups->flags |= SD_SHARE_CPUCAPACITY;
+ parent->parent->groups->flags = tmp->flags;
}

/*