55 lines
1.5 KiB
Diff
55 lines
1.5 KiB
Diff
From b2103f830327ab5d1e6f49134c22d3c5adfb52cc Mon Sep 17 00:00:00 2001
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From: Clark Williams <williams@redhat.com>
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Date: Sat, 30 Jul 2011 21:55:53 -0500
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Subject: [PATCH 50/62] sysfs: Add /sys/kernel/realtime entry
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Add a /sys/kernel entry to indicate that the kernel is a
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realtime kernel.
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Clark says that he needs this for udev rules, udev needs to evaluate
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if its a PREEMPT_RT kernel a few thousand times and parsing uname
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output is too slow or so.
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Are there better solutions? Should it exist and return 0 on !-rt?
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Signed-off-by: Clark Williams <williams@redhat.com>
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Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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---
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kernel/ksysfs.c | 12 ++++++++++++
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1 file changed, 12 insertions(+)
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diff --git a/kernel/ksysfs.c b/kernel/ksysfs.c
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index 65dba9076f31..ab18048e2186 100644
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--- a/kernel/ksysfs.c
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+++ b/kernel/ksysfs.c
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@@ -142,6 +142,15 @@ KERNEL_ATTR_RO(vmcoreinfo);
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#endif /* CONFIG_CRASH_CORE */
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+#if defined(CONFIG_PREEMPT_RT)
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+static ssize_t realtime_show(struct kobject *kobj,
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+ struct kobj_attribute *attr, char *buf)
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+{
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+ return sprintf(buf, "%d\n", 1);
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+}
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+KERNEL_ATTR_RO(realtime);
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+#endif
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+
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/* whether file capabilities are enabled */
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static ssize_t fscaps_show(struct kobject *kobj,
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struct kobj_attribute *attr, char *buf)
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@@ -232,6 +241,9 @@ static struct attribute * kernel_attrs[] = {
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#ifndef CONFIG_TINY_RCU
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&rcu_expedited_attr.attr,
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&rcu_normal_attr.attr,
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+#endif
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+#ifdef CONFIG_PREEMPT_RT
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+ &realtime_attr.attr,
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#endif
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NULL
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};
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--
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2.43.0
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