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From: Valentin Schneider <valentin.schneider@arm.com>
To: linux-kernel@vger.kernel.org
Cc: mingo@kernel.org, peterz@infradead.org,
	vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
	morten.rasmussen@arm.com, Quentin Perret <qperret@google.com>
Subject: [PATCH v4 07/10] sched/topology: Add more flags to the SD degeneration mask
Date: Fri, 31 Jul 2020 12:54:59 +0100	[thread overview]
Message-ID: <20200731115502.12954-8-valentin.schneider@arm.com> (raw)
In-Reply-To: <20200731115502.12954-1-valentin.schneider@arm.com>

I don't think it is going to change much in practice, but we were missing
those:

o SD_BALANCE_WAKE: Used just like the other SD_BALANCE_* flags, so also
  needs > 1 group.
o SD_ASYM_PACKING: Hinges on load balancing (periodic / wakeup), thus needs
  > 1 group to happen
o SD_OVERLAP: Describes domains with overlapping groups; can't have
  overlaps with a single group.

SD_PREFER_SIBLING is as always the odd one out: we currently consider it
in sd_parent_degenerate() but not in sd_degenerate(). It too hinges on load
balancing, and thus won't have any effect when set on a domain with a
single group. Add it to the sd_degenerate() groups mask.

Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
---
 kernel/sched/topology.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index cda02507aebf..93a7ff52335b 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -161,11 +161,15 @@ static int sd_degenerate(struct sched_domain *sd)
 
 	/* Following flags need at least 2 groups */
 	if (sd->flags & (SD_BALANCE_NEWIDLE |
+			 SD_BALANCE_WAKE |
 			 SD_BALANCE_FORK |
 			 SD_BALANCE_EXEC |
+			 SD_ASYM_PACKING |
 			 SD_SHARE_CPUCAPACITY |
 			 SD_ASYM_CPUCAPACITY |
-			 SD_SHARE_PKG_RESOURCES)) {
+			 SD_SHARE_PKG_RESOURCES |
+			 SD_OVERLAP |
+			 SD_PREFER_SIBLING)) {
 		if (sd->groups != sd->groups->next)
 			return 0;
 	}
@@ -191,11 +195,14 @@ sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent)
 	/* Flags needing groups don't count if only 1 group in parent */
 	if (parent->groups == parent->groups->next) {
 		pflags &= ~(SD_BALANCE_NEWIDLE |
+			    SD_BALANCE_WAKE |
 			    SD_BALANCE_FORK |
 			    SD_BALANCE_EXEC |
+			    SD_ASYM_PACKING |
 			    SD_ASYM_CPUCAPACITY |
 			    SD_SHARE_CPUCAPACITY |
 			    SD_SHARE_PKG_RESOURCES |
+			    SD_OVERLAP |
 			    SD_PREFER_SIBLING);
 		if (nr_node_ids == 1)
 			pflags &= ~SD_SERIALIZE;
-- 
2.27.0


  parent reply	other threads:[~2020-07-31 12:05 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-31 11:54 [PATCH v4 00/10] sched: Instrument sched domain flags Valentin Schneider
2020-07-31 11:54 ` [PATCH v4 01/10] ARM, sched/topology: Remove SD_SHARE_POWERDOMAIN Valentin Schneider
2020-07-31 11:54 ` [PATCH v4 02/10] ARM: Revert back to default scheduler topology Valentin Schneider
2020-07-31 11:54 ` [PATCH v4 03/10] sched/topology: Propagate SD_ASYM_CPUCAPACITY upwards Valentin Schneider
2020-08-06 14:20   ` Ingo Molnar
2020-08-06 16:19     ` Valentin Schneider
2020-08-06 16:46       ` Ingo Molnar
2020-07-31 11:54 ` [PATCH v4 04/10] sched/topology: Split out SD_* flags declaration to its own file Valentin Schneider
2020-07-31 11:54 ` [PATCH v4 05/10] sched/topology: Define and assign sched_domain flag metadata Valentin Schneider
2020-08-04 11:08   ` peterz
2020-08-04 11:12     ` Valentin Schneider
2020-08-06 14:07   ` Ingo Molnar
2020-08-06 16:18     ` Valentin Schneider
2020-08-08  0:19       ` Valentin Schneider
2020-07-31 11:54 ` [PATCH v4 06/10] sched/topology: Verify SD_* flags setup when sched_debug is on Valentin Schneider
2020-07-31 11:54 ` Valentin Schneider [this message]
2020-08-06 13:57   ` [PATCH v4 07/10] sched/topology: Add more flags to the SD degeneration mask Ingo Molnar
2020-07-31 11:55 ` [PATCH v4 08/10] sched/topology: Remove SD_SERIALIZE degeneration special case Valentin Schneider
2020-07-31 11:55 ` [PATCH v4 09/10] sched/topology: Introduce SD metaflag for flags needing > 1 groups Valentin Schneider
2020-07-31 11:55 ` [PATCH v4 10/10] sched/topology: Use prebuilt SD flag degeneration mask Valentin Schneider
2020-08-06 11:25 ` [PATCH v4 00/10] sched: Instrument sched domain flags Dietmar Eggemann

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