linux-kernel - [PATCH v6 01/17] ARM, sched/topology: Remove SD_SHARE

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Date:   Mon, 17 Aug 2020 12:29:47 +0100
From:   Valentin Schneider <valentin.schneider@....com>
To:     linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Cc:     Russell King <linux@...linux.org.uk>,
        Morten Rasmussen <morten.rasmussen@....com>,
        Dietmar Eggemann <dietmar.eggemann@....com>, mingo@...nel.org,
        peterz@...radead.org, vincent.guittot@...aro.org,
        Quentin Perret <qperret@...gle.com>
Subject: [PATCH v6 01/17] ARM, sched/topology: Remove SD_SHARE_POWERDOMAIN

This flag was introduced in 2014 by commit

  d77b3ed5c9f8 ("sched: Add a new SD_SHARE_POWERDOMAIN for sched_domain")

but AFAIA it was never leveraged by the scheduler. The closest thing I can
think of is EAS caring about frequency domains, and it does that by
leveraging performance domains.

Remove the flag. No change in functionality is expected.

Cc: Russell King <linux@...linux.org.uk>
Suggested-by: Morten Rasmussen <morten.rasmussen@....com>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@....com>
Signed-off-by: Valentin Schneider <valentin.schneider@....com>
---
 arch/arm/kernel/topology.c     |  2 +-
 include/linux/sched/topology.h | 13 ++++++-------
 kernel/sched/topology.c        | 10 +++-------
 3 files changed, 10 insertions(+), 15 deletions(-)

diff --git a/arch/arm/kernel/topology.c b/arch/arm/kernel/topology.c
index b5adaf744630..353f3ee660e4 100644
--- a/arch/arm/kernel/topology.c
+++ b/arch/arm/kernel/topology.c
@@ -243,7 +243,7 @@ void store_cpu_topology(unsigned int cpuid)
 
 static inline int cpu_corepower_flags(void)
 {
-	return SD_SHARE_PKG_RESOURCES  | SD_SHARE_POWERDOMAIN;
+	return SD_SHARE_PKG_RESOURCES;
 }
 
 static struct sched_domain_topology_level arm_topology[] = {
diff --git a/include/linux/sched/topology.h b/include/linux/sched/topology.h
index 820511289857..6ec7d7c1d1e3 100644
--- a/include/linux/sched/topology.h
+++ b/include/linux/sched/topology.h
@@ -18,13 +18,12 @@
 #define SD_WAKE_AFFINE		0x0010	/* Wake task to waking CPU */
 #define SD_ASYM_CPUCAPACITY	0x0020  /* Domain members have different CPU capacities */
 #define SD_SHARE_CPUCAPACITY	0x0040	/* Domain members share CPU capacity */
-#define SD_SHARE_POWERDOMAIN	0x0080	/* Domain members share power domain */
-#define SD_SHARE_PKG_RESOURCES	0x0100	/* Domain members share CPU pkg resources */
-#define SD_SERIALIZE		0x0200	/* Only a single load balancing instance */
-#define SD_ASYM_PACKING		0x0400  /* Place busy groups earlier in the domain */
-#define SD_PREFER_SIBLING	0x0800	/* Prefer to place tasks in a sibling domain */
-#define SD_OVERLAP		0x1000	/* sched_domains of this level overlap */
-#define SD_NUMA			0x2000	/* cross-node balancing */
+#define SD_SHARE_PKG_RESOURCES	0x0080	/* Domain members share CPU pkg resources */
+#define SD_SERIALIZE		0x0100	/* Only a single load balancing instance */
+#define SD_ASYM_PACKING		0x0200  /* Place busy groups earlier in the domain */
+#define SD_PREFER_SIBLING	0x0400	/* Prefer to place tasks in a sibling domain */
+#define SD_OVERLAP		0x0800	/* sched_domains of this level overlap */
+#define SD_NUMA			0x1000	/* cross-node balancing */
 
 #ifdef CONFIG_SCHED_SMT
 static inline int cpu_smt_flags(void)
diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index 9079d865a935..865fff3ef20a 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -148,8 +148,7 @@ static int sd_degenerate(struct sched_domain *sd)
 			 SD_BALANCE_EXEC |
 			 SD_SHARE_CPUCAPACITY |
 			 SD_ASYM_CPUCAPACITY |
-			 SD_SHARE_PKG_RESOURCES |
-			 SD_SHARE_POWERDOMAIN)) {
+			 SD_SHARE_PKG_RESOURCES)) {
 		if (sd->groups != sd->groups->next)
 			return 0;
 	}
@@ -180,8 +179,7 @@ sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent)
 			    SD_ASYM_CPUCAPACITY |
 			    SD_SHARE_CPUCAPACITY |
 			    SD_SHARE_PKG_RESOURCES |
-			    SD_PREFER_SIBLING |
-			    SD_SHARE_POWERDOMAIN);
+			    SD_PREFER_SIBLING);
 		if (nr_node_ids == 1)
 			pflags &= ~SD_SERIALIZE;
 	}
@@ -1292,7 +1290,6 @@ int __read_mostly		node_reclaim_distance = RECLAIM_DISTANCE;
  *   SD_SHARE_CPUCAPACITY   - describes SMT topologies
  *   SD_SHARE_PKG_RESOURCES - describes shared caches
  *   SD_NUMA                - describes NUMA topologies
- *   SD_SHARE_POWERDOMAIN   - describes shared power domain
  *
  * Odd one out, which beside describing the topology has a quirk also
  * prescribes the desired behaviour that goes along with it:
@@ -1303,8 +1300,7 @@ int __read_mostly		node_reclaim_distance = RECLAIM_DISTANCE;
 	(SD_SHARE_CPUCAPACITY	|	\
 	 SD_SHARE_PKG_RESOURCES |	\
 	 SD_NUMA		|	\
-	 SD_ASYM_PACKING	|	\
-	 SD_SHARE_POWERDOMAIN)
+	 SD_ASYM_PACKING)
 
 static struct sched_domain *
 sd_init(struct sched_domain_topology_level *tl,
-- 
2.27.0