[PATCH RT 08/16] kernel/hotplug: restore original cpu mask oncpu/down
From: Steven Rostedt <rostedt@goodmis.org>
Date: 2013-09-09 15:27:42
Also in:
lkml
Subsystem:
cpu hotplug, the rest · Maintainers:
Thomas Gleixner, Peter Zijlstra, Linus Torvalds
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> If a task which is allowed to run only on CPU X puts CPU Y down then it will be allowed on all CPUs but the on CPU Y after it comes back from kernel. This patch ensures that we don't lose the initial setting unless the CPU the task is running is going down. Cc: stable-rt@vger.kernel.org Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> --- kernel/cpu.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 25853dc..4abfd5d 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c@@ -497,6 +497,7 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen) .hcpu = hcpu, }; cpumask_var_t cpumask; + cpumask_var_t cpumask_org; if (num_online_cpus() == 1) return -EBUSY;
@@ -507,6 +508,12 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen) /* Move the downtaker off the unplug cpu */ if (!alloc_cpumask_var(&cpumask, GFP_KERNEL)) return -ENOMEM; + if (!alloc_cpumask_var(&cpumask_org, GFP_KERNEL)) { + free_cpumask_var(cpumask); + return -ENOMEM; + } + + cpumask_copy(cpumask_org, tsk_cpus_allowed(current)); cpumask_andnot(cpumask, cpu_online_mask, cpumask_of(cpu)); set_cpus_allowed_ptr(current, cpumask); free_cpumask_var(cpumask);
@@ -515,7 +522,8 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen) if (mycpu == cpu) { printk(KERN_ERR "Yuck! Still on unplug CPU\n!"); migrate_enable(); - return -EBUSY; + err = -EBUSY; + goto restore_cpus; } cpu_hotplug_begin();
@@ -573,6 +581,9 @@ out_cancel: cpu_hotplug_done(); if (!err) cpu_notify_nofail(CPU_POST_DEAD | mod, hcpu); +restore_cpus: + set_cpus_allowed_ptr(current, cpumask_org); + free_cpumask_var(cpumask_org); return err; }
--
1.7.10.4