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

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

[Chen Yu]

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/20230530115527.GC156198@hirez.programming.kicks-ass.net #1
Suggested-by: Ricardo Neri <ricardo.neri@intel.com>
Reported-by: Yicong Yang <yangyicong@huawei.com>
Closes: https://lore.kernel.org/lkml/ce714341-af58-2522-69a8-321f02c82893@huawei.com/
Signed-off-by: Chen Yu <yu.c.chen@intel.com>
---
 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

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

[Tim Chen]

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/20230530115527.GC156198@hirez.programming.kicks-ass.net #1
> Suggested-by: Ricardo Neri <ricardo.neri@intel.com>
> Reported-by: Yicong Yang <yangyicong@huawei.com>
> Closes: https://lore.kernel.org/lkml/ce714341-af58-2522-69a8-321f02c82893@huawei.com/
> Signed-off-by: Chen Yu <yu.c.chen@intel.com>
> ---
>  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 <tim.c.chen@linux.intel.com>

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

[Yicong Yang]

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/20230530115527.GC156198@hirez.programming.kicks-ass.net #1
> Suggested-by: Ricardo Neri <ricardo.neri@intel.com>
> Reported-by: Yicong Yang <yangyicong@huawei.com>
> Closes: https://lore.kernel.org/lkml/ce714341-af58-2522-69a8-321f02c82893@huawei.com/
> Signed-off-by: Chen Yu <yu.c.chen@intel.com>

Reviewed-by: Yicong Yang <yangyicong@hisilicon.com>

> ---
>  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;
>  			}
>  
>  			/*
> 

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

[tip-bot2 for Chen Yu]

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 <yu.c.chen@intel.com>
AuthorDate:    Thu, 13 Jul 2023 09:31:33 +08:00
Committer:     Peter Zijlstra <peterz@infradead.org>
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 <yangyicong@huawei.com>
Suggested-by: Ricardo Neri <ricardo.neri@intel.com>
Signed-off-by: Chen Yu <yu.c.chen@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Tim Chen <tim.c.chen@linux.intel.com>
Reviewed-by: Yicong Yang <yangyicong@hisilicon.com>
Link: https://lore.kernel.org/r/20230713013133.2314153-1-yu.c.chen@intel.com
---
 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;
 			}
 
 			/*