From 49cdbf3b800933bfb25a49ef1cbad918a072574e Mon Sep 17 00:00:00 2001 From: Alex Shi Date: Thu, 19 Jun 2014 13:47:35 +0800 Subject: [PATCH] HMP: use per cpu cpuidle driver to fix deadlock in hmp_idle_pull Using per cpu cpuidle driver to fix deadlock in hmp_idle_pull. Otherwise a deadlock happened when do bl_idle_init. [ 113.878664] other info that might help us debug this: [ 113.878667] Possible unsafe locking scenario: [ 113.878667] [ 113.878670] CPU0 [ 113.878673] ---- [ 113.878681] lock(cpuidle_driver_lock); [ 113.878684] [ 113.878691] lock(cpuidle_driver_lock); [ 113.878693] [ 113.878693] *** DEADLOCK *** [ 113.878693] [ 113.878697] 1 lock held by ksoftirqd/4/28: [ 113.878719] #0: (hmp_force_migration){+.....}, at: [] hmp_idle_pull+0x49/0x508 This patch is just a quick/cheap workaround for cpuidle_driver_lock deadlock. It works for TC2 and any other platform where the idle driver cannot be changed at runtime. Signed-off-by: Alex Shi --- kernel/sched/fair.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 71da724..0269273 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -3587,10 +3587,12 @@ static enum hrtimer_restart hmp_cpu_keepalive_notify(struct hrtimer *hrtimer) * If there are any, set ns_delay to * ('target_residency of state with shortest too-big latency' - 1) * 1000. */ -static void hmp_keepalive_delay(unsigned int *ns_delay) +static void hmp_keepalive_delay(int cpu, unsigned int *ns_delay) { + struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu); struct cpuidle_driver *drv; - drv = cpuidle_driver_ref(); + + drv = cpuidle_get_cpu_driver(dev); if (drv) { unsigned int us_delay = UINT_MAX; unsigned int us_max_delay = *ns_delay / 1000; @@ -3609,7 +3611,6 @@ static void hmp_keepalive_delay(unsigned int *ns_delay) else *ns_delay = 1000 * (us_delay - 1); } - cpuidle_driver_unref(); } static void hmp_cpu_keepalive_trigger(void) @@ -3623,7 +3624,7 @@ static void hmp_cpu_keepalive_trigger(void) CLOCK_MONOTONIC, HRTIMER_MODE_REL_PINNED); keepalive->timer.function = hmp_cpu_keepalive_notify; - hmp_keepalive_delay(&ns_delay); + hmp_keepalive_delay(cpu, &ns_delay); keepalive->delay = ns_to_ktime(ns_delay); keepalive->init = true; } -- 1.9.1