Re: [RFC PATCH v2 3/7] sched/idle: Add poll before enter real idle path

From: Quan Xu
Date: Fri Sep 01 2017 - 01:58:08 EST


on 2017/8/29 20:45, Peter Zijlstra wrote:

On Tue, Aug 29, 2017 at 11:46:37AM +0000, Yang Zhang wrote:
Add poll in do_idle. For UP VM, if there are running task, it will not
goes into idle path, so we only enable poll in SMP VM.

Signed-off-by: Yang Zhang <yang.zhang.wz@xxxxxxxxx>
Signed-off-by: Quan Xu <quan.xu0@xxxxxxxxx>
Broken SoB chain.
 Peter, I can't follow 'Broken SoB chain'.. could you more about it?

 -Quan

diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
index 6c23e30..b374744 100644
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c
@@ -74,6 +74,7 @@ static noinline int __cpuidle cpu_idle_poll(void)
}
/* Weak implementations for optional arch specific functions */
+void __weak arch_cpu_idle_poll(void) { }
void __weak arch_cpu_idle_prepare(void) { }
void __weak arch_cpu_idle_enter(void) { }
And not a word on why we need a new arch hook. What's wrong with
arch_cpu_idle_enter() for instance?