| From 241ebc0c1b8506bb173624d98670e60c55a67de4 Mon Sep 17 00:00:00 2001 |
| From: Clark Williams <williams@redhat.com> |
| Date: Sat, 30 Jul 2011 21:55:53 -0500 |
| Subject: [PATCH] sysfs: Add /sys/kernel/realtime entry |
| |
| Add a /sys/kernel entry to indicate that the kernel is a |
| realtime kernel. |
| |
| Clark says that he needs this for udev rules, udev needs to evaluate |
| if its a PREEMPT_RT kernel a few thousand times and parsing uname |
| output is too slow or so. |
| |
| Are there better solutions? Should it exist and return 0 on !-rt? |
| |
| Signed-off-by: Clark Williams <williams@redhat.com> |
| Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> |
| |
| diff --git a/kernel/ksysfs.c b/kernel/ksysfs.c |
| index 23cd70651238..9d23330a5a90 100644 |
| --- a/kernel/ksysfs.c |
| +++ b/kernel/ksysfs.c |
| @@ -140,6 +140,15 @@ KERNEL_ATTR_RO(vmcoreinfo); |
| |
| #endif /* CONFIG_CRASH_CORE */ |
| |
| +#if defined(CONFIG_PREEMPT_RT_FULL) |
| +static ssize_t realtime_show(struct kobject *kobj, |
| + struct kobj_attribute *attr, char *buf) |
| +{ |
| + return sprintf(buf, "%d\n", 1); |
| +} |
| +KERNEL_ATTR_RO(realtime); |
| +#endif |
| + |
| /* whether file capabilities are enabled */ |
| static ssize_t fscaps_show(struct kobject *kobj, |
| struct kobj_attribute *attr, char *buf) |
| @@ -231,6 +240,9 @@ static struct attribute * kernel_attrs[] = { |
| &rcu_expedited_attr.attr, |
| &rcu_normal_attr.attr, |
| #endif |
| +#ifdef CONFIG_PREEMPT_RT_FULL |
| + &realtime_attr.attr, |
| +#endif |
| NULL |
| }; |
| |
| -- |
| 2.1.4 |
| |
