From 86ff244b7222b5d5734b2c195ba28c7bbb5b6b0a Mon Sep 17 00:00:00 2001 From: Scott Wood Date: Sat, 12 Oct 2019 01:52:12 -0500 Subject: [PATCH 307/347] sched: migrate_enable: Use select_fallback_rq() Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.246-rt110.tar.xz [ Upstream commit adfa969d4cfcc995a9d866020124e50f1827d2d1 ] migrate_enable() currently open-codes a variant of select_fallback_rq(). However, it does not have the "No more Mr. Nice Guy" fallback and thus it will pass an invalid CPU to the migration thread if cpus_mask only contains a CPU that is !active. Signed-off-by: Scott Wood Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Steven Rostedt (VMware) --- kernel/sched/core.c | 25 ++++++++++--------------- 1 file changed, 10 insertions(+), 15 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 6f91ee2b7e91..7eb3037c0b35 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -7329,6 +7329,7 @@ void migrate_enable(void) if (p->migrate_disable_update) { struct rq *rq; struct rq_flags rf; + int cpu = task_cpu(p); rq = task_rq_lock(p, &rf); update_rq_clock(rq); @@ -7338,21 +7339,15 @@ void migrate_enable(void) p->migrate_disable_update = 0; - WARN_ON(smp_processor_id() != task_cpu(p)); - if (!cpumask_test_cpu(task_cpu(p), &p->cpus_mask)) { - const struct cpumask *cpu_valid_mask = cpu_active_mask; - struct migration_arg arg; - unsigned int dest_cpu; - - if (p->flags & PF_KTHREAD) { - /* - * Kernel threads are allowed on online && !active CPUs - */ - cpu_valid_mask = cpu_online_mask; - } - dest_cpu = cpumask_any_and(cpu_valid_mask, &p->cpus_mask); - arg.task = p; - arg.dest_cpu = dest_cpu; + WARN_ON(smp_processor_id() != cpu); + if (!cpumask_test_cpu(cpu, &p->cpus_mask)) { + struct migration_arg arg = { p }; + struct rq_flags rf; + + rq = task_rq_lock(p, &rf); + update_rq_clock(rq); + arg.dest_cpu = select_fallback_rq(cpu, p); + task_rq_unlock(rq, p, &rf); unpin_current_cpu(); preempt_lazy_enable(); -- 2.36.1