summaryrefslogtreecommitdiffstats
path: root/debian/patches-rt/0147-irqtime-Make-accounting-correct-on-RT.patch
diff options
context:
space:
mode:
Diffstat (limited to 'debian/patches-rt/0147-irqtime-Make-accounting-correct-on-RT.patch')
-rw-r--r--debian/patches-rt/0147-irqtime-Make-accounting-correct-on-RT.patch54
1 files changed, 54 insertions, 0 deletions
diff --git a/debian/patches-rt/0147-irqtime-Make-accounting-correct-on-RT.patch b/debian/patches-rt/0147-irqtime-Make-accounting-correct-on-RT.patch
new file mode 100644
index 000000000..576b5391b
--- /dev/null
+++ b/debian/patches-rt/0147-irqtime-Make-accounting-correct-on-RT.patch
@@ -0,0 +1,54 @@
+From a4b2fa58f0b8dabae3f30be80fe317da32c5b121 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 9 Mar 2021 09:55:54 +0100
+Subject: [PATCH 147/323] irqtime: Make accounting correct on RT
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+vtime_account_irq and irqtime_account_irq() base checks on preempt_count()
+which fails on RT because preempt_count() does not contain the softirq
+accounting which is seperate on RT.
+
+These checks do not need the full preempt count as they only operate on the
+hard and softirq sections.
+
+Use irq_count() instead which provides the correct value on both RT and non
+RT kernels. The compiler is clever enough to fold the masking for !RT:
+
+ 99b: 65 8b 05 00 00 00 00 mov %gs:0x0(%rip),%eax
+ - 9a2: 25 ff ff ff 7f and $0x7fffffff,%eax
+ + 9a2: 25 00 ff ff 00 and $0xffff00,%eax
+
+Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Tested-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/sched/cputime.c | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
+index 02a7932c7383..02a5aa60fe7e 100644
+--- a/kernel/sched/cputime.c
++++ b/kernel/sched/cputime.c
+@@ -60,7 +60,7 @@ void irqtime_account_irq(struct task_struct *curr, unsigned int offset)
+ cpu = smp_processor_id();
+ delta = sched_clock_cpu(cpu) - irqtime->irq_start_time;
+ irqtime->irq_start_time += delta;
+- pc = preempt_count() - offset;
++ pc = irq_count() - offset;
+
+ /*
+ * We do not account for softirq time from ksoftirqd here.
+@@ -421,7 +421,7 @@ void vtime_task_switch(struct task_struct *prev)
+
+ void vtime_account_irq(struct task_struct *tsk, unsigned int offset)
+ {
+- unsigned int pc = preempt_count() - offset;
++ unsigned int pc = irq_count() - offset;
+
+ if (pc & HARDIRQ_OFFSET) {
+ vtime_account_hardirq(tsk);
+--
+2.43.0
+