Subject: [PATCH 28/33] sched: Switch the fallback task allowed cpumask to HK_TYPE_DOMAIN

From: Frederic Weisbecker <[email-masked]>
Date: Thu, 1 Jan 2026 23:13:53 +0100

Tasks that have all their allowed CPUs offline don't want their affinity
to fallback on either nohz_full CPUs or on domain isolated CPUs. And
since nohz_full implies domain isolation, checking the latter is enough
to verify both.

Therefore exclude domain isolation from fallback task affinity.

Signed-off-by: Frederic Weisbecker <[email-masked]>
Acked-by: Waiman Long <[email-masked]>
---
 include/linux/mmu_context.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/mmu_context.h b/include/linux/mmu_context.h
index ac01dc4eb2ce..ed3dd0f3fe19 100644
--- a/include/linux/mmu_context.h
+++ b/include/linux/mmu_context.h
@@ -24,7 +24,7 @@ static inline void leave_mm(void) { }
 #ifndef task_cpu_possible_mask
 # define task_cpu_possible_mask(p)	cpu_possible_mask
 # define task_cpu_possible(cpu, p)	true
-# define task_cpu_fallback_mask(p)	housekeeping_cpumask(HK_TYPE_TICK)
+# define task_cpu_fallback_mask(p)	housekeeping_cpumask(HK_TYPE_DOMAIN)
 #else
 # define task_cpu_possible(cpu, p)	cpumask_test_cpu((cpu), task_cpu_possible_mask(p))
 #endif
-- 
2.51.1