The following commit has been merged into the sched/core branch of tip:
Commit-ID: 3dc6f6c8efe2d9148865664fffbe9dd89fb0d157
Gitweb: https://git.kernel.org/tip/3dc6f6c8efe2d9148865664fffbe9dd89fb0d157
Author: Ingo Molnar <mingo@xxxxxxxxxx>
AuthorDate: Fri, 08 Mar 2024 11:58:59 +01:00
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Tue, 12 Mar 2024 11:59:43 +01:00
sched/balancing: Update run_rebalance_domains() comments
The first sentence of the comment explaining run_rebalance_domains()
is historic and not true anymore:
* run_rebalance_domains is triggered when needed from the scheduler tick.
.. contradicted/modified by the second sentence:
* Also triggered for NOHZ idle balancing (with NOHZ_BALANCE_KICK set).
Avoid that kind of confusion straight away and explain from what
places sched_balance_softirq() is triggered.
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Reviewed-by: Vincent Guittot <vincent.guittot@xxxxxxxxxx>
Acked-by: Valentin Schneider <vschneid@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20240308105901.1096078-9-mingo@xxxxxxxxxx
---
kernel/sched/fair.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index f3c03c6..b567c07 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -12409,9 +12409,12 @@ out:
}
/*
- * This softirq may be triggered from the scheduler tick, or by
- * any of the flags in NOHZ_KICK_MASK: NOHZ_BALANCE_KICK,
- * NOHZ_STATS_KICK or NOHZ_NEXT_KICK.
+ * This softirq handler is triggered via SCHED_SOFTIRQ from two places:
+ *
+ * - directly from the local scheduler_tick() for periodic load balancing
+ *
+ * - indirectly from a remote scheduler_tick() for NOHZ idle balancing
+ * through the SMP cross-call nohz_csd_func()
*/
static __latent_entropy void run_rebalance_domains(struct softirq_action *h)
{
|