From ede03b5d80a61a01217635de00b805c53d87e474 Mon Sep 17 00:00:00 2001 From: Juri Lelli Date: Tue, 6 Dec 2016 11:50:53 +0000 Subject: [PATCH] sched/walt: kill {min,max}_capacity {min,max}_capacity are static variables that are only updated from __update_min_max_capacity(), but not used anywhere else. Remove them together with the function updating them. This has also the nice side effect of fixing a LOCKDEP warning related to locking all CPUs in update_min_max_capacity(), as reported by Ke Wang: [ 2.853595] c0 ============================================= [ 2.859219] c0 [ INFO: possible recursive locking detected ] [ 2.864852] c0 4.4.6+ #5 Tainted: G W [ 2.869604] c0 --------------------------------------------- [ 2.875230] c0 swapper/0/1 is trying to acquire lock: [ 2.880248] (&rq->lock){-.-.-.}, at: [] cpufreq_notifier_policy+0x2e8/0x37c [ 2.888815] c0 [ 2.888815] c0 but task is already holding lock: [ 2.895132] (&rq->lock){-.-.-.}, at: [] cpufreq_notifier_policy+0x2e8/0x37c [ 2.903700] c0 [ 2.903700] c0 other info that might help us debug this: [ 2.910710] c0 Possible unsafe locking scenario: [ 2.910710] c0 [ 2.917112] c0 CPU0 [ 2.919795] c0 ---- [ 2.922478] lock(&rq->lock); [ 2.925507] lock(&rq->lock); [ 2.928536] c0 [ 2.928536] c0 *** DEADLOCK *** [ 2.928536] c0 [ 2.935200] c0 May be due to missing lock nesting notation [ 2.935200] c0 [ 2.942471] c0 7 locks held by swapper/0/1: [ 2.946623] #0: (&dev->mutex){......}, at: [] __driver_attach+0x64/0xb8 [ 2.954931] #1: (&dev->mutex){......}, at: [] __driver_attach+0x74/0xb8 [ 2.963239] #2: (cpu_hotplug.lock){++++++}, at: [] get_online_cpus+0x48/0xa8 [ 2.971979] #3: (subsys mutex#6){+.+.+.}, at: [] subsys_interface_register+0x44/0xc0 [ 2.981411] #4: (&policy->rwsem){+.+.+.}, at: [] cpufreq_online+0x330/0x76c [ 2.990065] #5: ((cpufreq_policy_notifier_list).rwsem){.+.+..}, at: [] blocking_notifier_call_chain+0x38/0xc4 [ 3.001661] #6: (&rq->lock){-.-.-.}, at: [] cpufreq_notifier_policy+0x2e8/0x37c [ 3.010661] c0 [ 3.010661] c0 stack backtrace: [ 3.015514] c0 CPU: 0 PID: 1 Comm: swapper/0 Tainted: G W 4.4.6+ #5 [ 3.022864] c0 Hardware name: Spreadtrum SP9860g Board (DT) [ 3.028402] c0 Call trace: [ 3.031092] c0 [] dump_backtrace+0x0/0x210 [ 3.036716] c0 [] show_stack+0x20/0x28 [ 3.041994] c0 [] dump_stack+0xa8/0xe0 [ 3.047273] c0 [] __lock_acquire+0x1e0c/0x2218 [ 3.053243] c0 [] lock_acquire+0xe0/0x280 [ 3.058784] c0 [] _raw_spin_lock+0x44/0x58 [ 3.064407] c0 [] cpufreq_notifier_policy+0x2e8/0x37c [ 3.070983] c0 [] blocking_notifier_call_chain+0x78/0xc4 [ 3.077820] c0 [] cpufreq_online+0x28c/0x76c [ 3.083618] c0 [] cpufreq_add_dev+0x98/0xdc [ 3.089331] c0 [] subsys_interface_register+0x84/0xc0 [ 3.095907] c0 [] cpufreq_register_driver+0x168/0x28c [ 3.102486] c0 [] sprd_cpufreq_probe+0x134/0x19c [ 3.108629] c0 [] platform_drv_probe+0x58/0xd0 [ 3.114599] c0 [] driver_probe_device+0x1e8/0x470 [ 3.120830] c0 [] __driver_attach+0xb4/0xb8 [ 3.126541] c0 [] bus_for_each_dev+0x6c/0xac [ 3.132339] c0 [] driver_attach+0x2c/0x34 [ 3.137877] c0 [] bus_add_driver+0x210/0x298 [ 3.143676] c0 [] driver_register+0x7c/0x114 [ 3.149476] c0 [] __platform_driver_register+0x60/0x6c [ 3.156139] c0 [] sprd_cpufreq_platdrv_init+0x18/0x20 [ 3.162714] c0 [] do_one_initcall+0xd0/0x1d8 [ 3.168514] c0 [] kernel_init_freeable+0x1fc/0x29c [ 3.174834] c0 [] kernel_init+0x20/0x12c [ 3.180281] c0 [] ret_from_fork+0x10/0x40 Reported-by: Ke Wang Signed-off-by: Juri Lelli --- kernel/sched/walt.c | 45 +-------------------------------------------- 1 file changed, 1 insertion(+), 44 deletions(-) diff --git a/kernel/sched/walt.c b/kernel/sched/walt.c index 2ffb1680b380..6e053bd9830c 100644 --- a/kernel/sched/walt.c +++ b/kernel/sched/walt.c @@ -62,8 +62,6 @@ static unsigned int max_possible_freq = 1; */ static unsigned int min_max_freq = 1; -static unsigned int max_capacity = 1024; -static unsigned int min_capacity = 1024; static unsigned int max_load_scale_factor = 1024; static unsigned int max_possible_capacity = 1024; @@ -869,39 +867,6 @@ void walt_fixup_busy_time(struct task_struct *p, int new_cpu) double_rq_unlock(src_rq, dest_rq); } -/* Keep track of max/min capacity possible across CPUs "currently" */ -static void __update_min_max_capacity(void) -{ - int i; - int max = 0, min = INT_MAX; - - for_each_online_cpu(i) { - if (cpu_rq(i)->capacity > max) - max = cpu_rq(i)->capacity; - if (cpu_rq(i)->capacity < min) - min = cpu_rq(i)->capacity; - } - - max_capacity = max; - min_capacity = min; -} - -static void update_min_max_capacity(void) -{ - unsigned long flags; - int i; - - local_irq_save(flags); - for_each_possible_cpu(i) - raw_spin_lock(&cpu_rq(i)->lock); - - __update_min_max_capacity(); - - for_each_possible_cpu(i) - raw_spin_unlock(&cpu_rq(i)->lock); - local_irq_restore(flags); -} - /* * Return 'capacity' of a cpu in reference to "least" efficient cpu, such that * least efficient cpu gets capacity of 1024 @@ -984,15 +949,9 @@ static int cpufreq_notifier_policy(struct notifier_block *nb, /* Initialized to policy->max in case policy->related_cpus is empty! */ unsigned int orig_max_freq = policy->max; - if (val != CPUFREQ_NOTIFY && val != CPUFREQ_REMOVE_POLICY && - val != CPUFREQ_CREATE_POLICY) + if (val != CPUFREQ_NOTIFY) return 0; - if (val == CPUFREQ_REMOVE_POLICY || val == CPUFREQ_CREATE_POLICY) { - update_min_max_capacity(); - return 0; - } - for_each_cpu(i, policy->related_cpus) { cpumask_copy(&cpu_rq(i)->freq_domain_cpumask, policy->related_cpus); @@ -1082,8 +1041,6 @@ static int cpufreq_notifier_policy(struct notifier_block *nb, max_load_scale_factor = highest_mplsf; } - __update_min_max_capacity(); - return 0; } -- 2.34.1