From 522fb20fbdbe48ed98f587d628637ff38ececd2d Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 17 Nov 2025 17:13:09 +0100 Subject: [PATCH] sched/fair: Have SD_SERIALIZE affect newidle balancing Also serialize the possiblty much more frequent newidle balancing for the 'expensive' domains that have SD_BALANCE set. Initial benchmarking by K Prateek and Tim showed no negative effect. Split out from the larger patch moving sched_balance_running around for ease of bisect and such. Suggested-by: Shrikanth Hegde Seconded-by: K Prateek Nayak Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/df068896-82f9-458d-8fff-5a2f654e8ffd@amd.com Link: https://patch.msgid.link/6fed119b723c71552943bfe5798c93851b30a361.1762800251.git.tim.c.chen@linux.intel.com # Conflicts: # kernel/sched/fair.c --- kernel/sched/fair.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 59b17f09166b8..071e07f8cb27d 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -11732,7 +11732,7 @@ redo: goto out_balanced; } - if (!need_unlock && (sd->flags & SD_SERIALIZE) && idle != CPU_NEWLY_IDLE) { + if (!need_unlock && (sd->flags & SD_SERIALIZE)) { int zero = 0; if (!atomic_try_cmpxchg_acquire(&sched_balance_running, &zero, 1)) goto out_balanced; -- 2.47.3