mirrors
/
linux-stable
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
1
0
Fork 0
Code Issues Releases Wiki Activity

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:

  9ee1cda5ee ("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: Morten Rasmussen <morten.rasmussen@arm.com>
[Changelog tweaks]
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Quentin Perret <qperret@google.com>
Link: https://lkml.kernel.org/r/20200206191957.12325-3-valentin.schneider@arm.com
This commit is contained in:
Morten Rasmussen 2020-02-06 19:19:55 +00:00 committed by Thomas Gleixner
parent b7a331615d
commit a526d46679
1 changed files with 3 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
kernel/sched/topology.c
View File

@ -1374,18 +1374,9 @@ 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)
sd->child->flags &= ~SD_PREFER_SIBLING;
for_each_lower_domain(t)
t->flags |= SD_BALANCE_WAKE;
}
/* Don't attempt to spread across CPUs of different capacities. */
if ((sd->flags & SD_ASYM_CPUCAPACITY) && sd->child)
sd->child->flags &= ~SD_PREFER_SIBLING;
if (sd->flags & SD_SHARE_CPUCAPACITY) {
sd->imbalance_pct = 110;