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linux/debian/patches-rt/sysfs__Add__sys_kernel_realtime_entry.patch
Konstantin Demin c3d09a3e94 initial commit
imported from https://salsa.debian.org/kernel-team/linux.git
commit 9d5cc9d9d6501d7f1dd7e194d4b245bd0b6c6a22
version 6.11.4-1
2024-10-23 12:12:30 +03:00

54 lines
1.5 KiB
Diff

Subject: sysfs: Add /sys/kernel/realtime entry
From: Clark Williams <williams@redhat.com>
Date: Sat Jul 30 21:55:53 2011 -0500
Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.11/older/patches-6.11-rt7.tar.xz
From: Clark Williams <williams@redhat.com>
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>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
kernel/ksysfs.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
---
--- a/kernel/ksysfs.c
+++ b/kernel/ksysfs.c
@@ -188,6 +188,15 @@ KERNEL_ATTR_RO(crash_elfcorehdr_size);
#endif /* CONFIG_VMCORE_INFO */
+#if defined(CONFIG_PREEMPT_RT)
+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)
@@ -286,6 +295,9 @@ static struct attribute * kernel_attrs[]
&rcu_expedited_attr.attr,
&rcu_normal_attr.attr,
#endif
+#ifdef CONFIG_PREEMPT_RT
+ &realtime_attr.attr,
+#endif
NULL
};