iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

smp/hotplug: Track booted once CPUs in a cpumask

Browse Source 
The booted once information which is required to deal with the MCE
broadcast issue on X86 correctly is stored in the per cpu hotplug state,
which is perfectly fine for the intended purpose.

X86 needs that information for supporting NMI broadcasting via shortcuts,
but retrieving it from per cpu data is cumbersome.

Move it to a cpumask so the information can be checked against the
cpu_present_mask quickly.

No functional change intended.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20190722105219.818822855@linutronix.de
This commit is contained in:
Thomas Gleixner 2019-07-22 20:47:16 +02:00
parent ad5e427e0f
commit e797bda3fd
2 changed files with 9 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
include/linux/cpumask.h
View File

@ -115,6 +115,8 @@ extern struct cpumask __cpu_active_mask;
#define cpu_active(cpu) ((cpu) == 0)
#endif
extern cpumask_t cpus_booted_once_mask;
static inline void cpu_max_bits_warn(unsigned int cpu, unsigned int bits)
{
#ifdef CONFIG_DEBUG_PER_CPU_MAPS

11
kernel/cpu.c
View File

@ -62,7 +62,6 @@ struct cpuhp_cpu_state {
bool rollback;
bool single;
bool bringup;
bool booted_once;
struct hlist_node *node;
struct hlist_node *last;
enum cpuhp_state cb_state;
@ -76,6 +75,10 @@ static DEFINE_PER_CPU(struct cpuhp_cpu_state, cpuhp_state) = {
.fail = CPUHP_INVALID,
};
#ifdef CONFIG_SMP
cpumask_t cpus_booted_once_mask;
#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);
@ -433,7 +436,7 @@ static inline bool cpu_smt_allowed(unsigned int cpu)
* CPU. Otherwise, a broadacasted MCE observing CR4.MCE=0b on any
* core will shutdown the machine.
*/
return !per_cpu(cpuhp_state, cpu).booted_once;
return !cpumask_test_cpu(cpu, &cpus_booted_once_mask);
}
#else
static inline bool cpu_smt_allowed(unsigned int cpu) { return true; }
@ -1066,7 +1069,7 @@ void notify_cpu_starting(unsigned int cpu)
int ret;
rcu_cpu_starting(cpu); /* Enables RCU usage on this CPU. */
st->booted_once = true;
cpumask_set_cpu(cpu, &cpus_booted_once_mask);
while (st->state < target) {
st->state++;
ret = cpuhp_invoke_callback(cpu, st->state, true, NULL, NULL);
@ -2334,7 +2337,7 @@ void __init boot_cpu_init(void)
void __init boot_cpu_hotplug_init(void)
{
#ifdef CONFIG_SMP
this_cpu_write(cpuhp_state.booted_once, true);
cpumask_set_cpu(smp_processor_id(), &cpus_booted_once_mask);
#endif
this_cpu_write(cpuhp_state.state, CPUHP_ONLINE);
}