diff options
Diffstat (limited to 'drivers/base/cpu.c')
| -rw-r--r-- | drivers/base/cpu.c | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c index fe6690ecf563..9ea22e165acd 100644 --- a/drivers/base/cpu.c +++ b/drivers/base/cpu.c @@ -19,6 +19,7 @@ #include <linux/cpufeature.h> #include <linux/tick.h> #include <linux/pm_qos.h> +#include <linux/delay.h> #include <linux/sched/isolation.h> #include "base.h" @@ -50,12 +51,30 @@ static int cpu_subsys_online(struct device *dev) int cpuid = dev->id; int from_nid, to_nid; int ret; + int retries = 0; from_nid = cpu_to_node(cpuid); if (from_nid == NUMA_NO_NODE) return -ENODEV; +retry: ret = cpu_device_up(dev); + + /* + * If -EBUSY is returned, it is likely that hotplug is temporarily + * disabled when cpu_hotplug_disable() was called. This condition is + * transient. So we retry after waiting for an exponentially + * increasing delay up to a total of at least 620ms as some PCI + * device initialization can take quite a while. + */ + if (ret == -EBUSY) { + retries++; + if (retries > 5) + return ret; + msleep(10 * (1 << retries)); + goto retry; + } + /* * When hot adding memory to memoryless node and enabling a cpu * on the node, node number of the cpu may internally change. @@ -282,6 +301,16 @@ static ssize_t print_cpus_nohz_full(struct device *dev, static DEVICE_ATTR(nohz_full, 0444, print_cpus_nohz_full, NULL); #endif +#ifdef CONFIG_CRASH_HOTPLUG +static ssize_t crash_hotplug_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + return sysfs_emit(buf, "%d\n", crash_hotplug_cpu_support()); +} +static DEVICE_ATTR_ADMIN_RO(crash_hotplug); +#endif + static void cpu_device_release(struct device *dev) { /* @@ -469,6 +498,9 @@ static struct attribute *cpu_root_attrs[] = { #ifdef CONFIG_NO_HZ_FULL &dev_attr_nohz_full.attr, #endif +#ifdef CONFIG_CRASH_HOTPLUG + &dev_attr_crash_hotplug.attr, +#endif #ifdef CONFIG_GENERIC_CPU_AUTOPROBE &dev_attr_modalias.attr, #endif |