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

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Date:   Mon, 31 Jul 2023 10:19:46 -0000
From:   "tip-bot2 for Chen Yu" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Yicong Yang <yangyicong@...wei.com>,
        Ricardo Neri <ricardo.neri@...el.com>,
        Chen Yu <yu.c.chen@...el.com>,
        "Peter Zijlstra (Intel)" <peterz@...radead.org>,
        Tim Chen <tim.c.chen@...ux.intel.com>,
        Yicong Yang <yangyicong@...ilicon.com>, x86@...nel.org,
        linux-kernel@...r.kernel.org
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 <yu.c.chen@...el.com>
AuthorDate:    Thu, 13 Jul 2023 09:31:33 +08:00
Committer:     Peter Zijlstra <peterz@...radead.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@...wei.com>
Suggested-by: Ricardo Neri <ricardo.neri@...el.com>
Signed-off-by: Chen Yu <yu.c.chen@...el.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Reviewed-by: Tim Chen <tim.c.chen@...ux.intel.com>
Reviewed-by: Yicong Yang <yangyicong@...ilicon.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;
 			}
 
 			/*