diff options
Diffstat (limited to 'debian/patches-rt/0227-cpu-hotplug-Implement-CPU-pinning.patch')
| -rw-r--r-- | debian/patches-rt/0227-cpu-hotplug-Implement-CPU-pinning.patch | 113 |
1 files changed, 113 insertions, 0 deletions
diff --git a/debian/patches-rt/0227-cpu-hotplug-Implement-CPU-pinning.patch b/debian/patches-rt/0227-cpu-hotplug-Implement-CPU-pinning.patch new file mode 100644 index 000000000..1a1ee7954 --- /dev/null +++ b/debian/patches-rt/0227-cpu-hotplug-Implement-CPU-pinning.patch @@ -0,0 +1,113 @@ +From: Thomas Gleixner <tglx@linutronix.de> +Date: Wed, 19 Jul 2017 17:31:20 +0200 +Subject: [PATCH 227/342] cpu/hotplug: Implement CPU pinning +Origin: https://git.kernel.org/cgit/linux/kernel/git/rt/linux-stable-rt.git/commit?id=6fa443c6c513b0e160a42bfbc0a4f3023fdf4edb + +Signed-off-by: Thomas Gleixner <tglx@linutronix.de> +--- + include/linux/sched.h | 1 + + kernel/cpu.c | 38 ++++++++++++++++++++++++++++++++++++++ + 2 files changed, 39 insertions(+) + +diff --git a/include/linux/sched.h b/include/linux/sched.h +index 577045ae8693..7523c0786a63 100644 +--- a/include/linux/sched.h ++++ b/include/linux/sched.h +@@ -671,6 +671,7 @@ struct task_struct { + #if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT_RT_BASE) + int migrate_disable; + int migrate_disable_update; ++ int pinned_on_cpu; + # ifdef CONFIG_SCHED_DEBUG + int migrate_disable_atomic; + # endif +diff --git a/kernel/cpu.c b/kernel/cpu.c +index f4c49bbc3fa3..56cb58fce84c 100644 +--- a/kernel/cpu.c ++++ b/kernel/cpu.c +@@ -78,6 +78,11 @@ static DEFINE_PER_CPU(struct cpuhp_cpu_state, cpuhp_state) = { + .fail = CPUHP_INVALID, + }; + ++#ifdef CONFIG_HOTPLUG_CPU ++static DEFINE_PER_CPU(struct rt_rw_lock, cpuhp_pin_lock) = \ ++ __RWLOCK_RT_INITIALIZER(cpuhp_pin_lock); ++#endif ++ + #if defined(CONFIG_LOCKDEP) && defined(CONFIG_SMP) + static struct lockdep_map cpuhp_state_up_map = + STATIC_LOCKDEP_MAP_INIT("cpuhp_state-up", &cpuhp_state_up_map); +@@ -289,7 +294,28 @@ static int cpu_hotplug_disabled; + */ + void pin_current_cpu(void) + { ++ struct rt_rw_lock *cpuhp_pin; ++ unsigned int cpu; ++ int ret; ++ ++again: ++ cpuhp_pin = this_cpu_ptr(&cpuhp_pin_lock); ++ ret = __read_rt_trylock(cpuhp_pin); ++ if (ret) { ++ current->pinned_on_cpu = smp_processor_id(); ++ return; ++ } ++ cpu = smp_processor_id(); ++ preempt_enable(); ++ ++ __read_rt_lock(cpuhp_pin); + ++ preempt_disable(); ++ if (cpu != smp_processor_id()) { ++ __read_rt_unlock(cpuhp_pin); ++ goto again; ++ } ++ current->pinned_on_cpu = cpu; + } + + /** +@@ -297,6 +323,13 @@ void pin_current_cpu(void) + */ + void unpin_current_cpu(void) + { ++ struct rt_rw_lock *cpuhp_pin = this_cpu_ptr(&cpuhp_pin_lock); ++ ++ if (WARN_ON(current->pinned_on_cpu != smp_processor_id())) ++ cpuhp_pin = per_cpu_ptr(&cpuhp_pin_lock, current->pinned_on_cpu); ++ ++ current->pinned_on_cpu = -1; ++ __read_rt_unlock(cpuhp_pin); + } + + DEFINE_STATIC_PERCPU_RWSEM(cpu_hotplug_lock); +@@ -921,6 +954,7 @@ static int take_cpu_down(void *_param) + + static int takedown_cpu(unsigned int cpu) + { ++ struct rt_rw_lock *cpuhp_pin = per_cpu_ptr(&cpuhp_pin_lock, cpu); + struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); + int err; + +@@ -933,11 +967,14 @@ static int takedown_cpu(unsigned int cpu) + */ + irq_lock_sparse(); + ++ __write_rt_lock(cpuhp_pin); ++ + /* + * So now all preempt/rcu users must observe !cpu_active(). + */ + err = stop_machine_cpuslocked(take_cpu_down, NULL, cpumask_of(cpu)); + if (err) { ++ __write_rt_unlock(cpuhp_pin); + /* CPU refused to die */ + irq_unlock_sparse(); + /* Unpark the hotplug thread so we can rollback there */ +@@ -956,6 +993,7 @@ static int takedown_cpu(unsigned int cpu) + wait_for_ap_thread(st, false); + BUG_ON(st->state != CPUHP_AP_IDLE_DEAD); + ++ __write_rt_unlock(cpuhp_pin); + /* Interrupts are moved away from the dying cpu, reenable alloc/free */ + irq_unlock_sparse(); + |