Commit a526d466 authored by Morten Rasmussen's avatar Morten Rasmussen Committed by Thomas Gleixner
Browse files

sched/topology: Remove SD_BALANCE_WAKE on asymmetric capacity systems 



SD_BALANCE_WAKE was previously added to lower sched_domain levels on
asymmetric CPU capacity systems by commit:

  9ee1cda5 ("sched/core: Enable SD_BALANCE_WAKE for asymmetric capacity systems")

to enable the use of find_idlest_cpu() and friends to find an appropriate
CPU for tasks.

That responsibility has now been shifted to select_idle_sibling() and
friends, and hence the flag can be removed. Note that this causes
asymmetric CPU capacity systems to no longer enter the slow wakeup path
(find_idlest_cpu()) on wakeups - only on execs and forks (which is aligned
with all other mainline topologies).

Signed-off-by: default avatarMorten Rasmussen <morten.rasmussen@arm.com>
[Changelog tweaks]
Signed-off-by: default avatarValentin Schneider <valentin.schneider@arm.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Reviewed-by: default avatarQuentin Perret <qperret@google.com>
Link: https://lkml.kernel.org/r/20200206191957.12325-3-valentin.schneider@arm.com
parent b7a33161

kernel/sched/topology.c

+3 −12
Original line number Diff line number Diff line
@@ -1374,19 +1374,10 @@ sd_init(struct sched_domain_topology_level *tl, 
	 * Convert topological properties into behaviour.

	 */



	if (sd->flags & SD_ASYM_CPUCAPACITY) {

		struct sched_domain *t = sd;



		/*

		 * Don't attempt to spread across CPUs of different capacities.

		 */

		if (sd->child)

	/* Don't attempt to spread across CPUs of different capacities. */

	if ((sd->flags & SD_ASYM_CPUCAPACITY) && sd->child)

		sd->child->flags &= ~SD_PREFER_SIBLING;



		for_each_lower_domain(t)

			t->flags |= SD_BALANCE_WAKE;

	}



	if (sd->flags & SD_SHARE_CPUCAPACITY) {

		sd->imbalance_pct = 110;