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From 8f58969bec3bc125c8257b4aea667ebb352cc73a Mon Sep 17 00:00:00 2001
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Fri, 21 Feb 2020 18:15:15 +0100
Subject: [PATCH 321/347] tracing: make preempt_lazy and migrate_disable
counter smaller
Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.246-rt110.tar.xz
[ Upstream commit dd430bf5ecb40f9a89679c85868826475d71de54 ]
The migrate_disable counter should not exceed 255 so it is enough to
store it in an 8bit field.
With this change we can move the `preempt_lazy_count' member into the
gap so the whole struct shrinks by 4 bytes to 12 bytes in total.
Remove the `padding' field, it is not needed.
Update the tracing fields in trace_define_common_fields() (it was
missing the preempt_lazy_count field).
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
include/linux/trace_events.h | 3 +--
kernel/trace/trace_events.c | 4 ++--
2 files changed, 3 insertions(+), 4 deletions(-)
diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
index 72864a11cec0..e26a85c1b7ba 100644
--- a/include/linux/trace_events.h
+++ b/include/linux/trace_events.h
@@ -62,8 +62,7 @@ struct trace_entry {
unsigned char flags;
unsigned char preempt_count;
int pid;
- unsigned short migrate_disable;
- unsigned short padding;
+ unsigned char migrate_disable;
unsigned char preempt_lazy_count;
};
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index fbb04cf1d5bc..9b1b1c6de2bd 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -188,8 +188,8 @@ static int trace_define_common_fields(void)
__common_field(unsigned char, flags);
__common_field(unsigned char, preempt_count);
__common_field(int, pid);
- __common_field(unsigned short, migrate_disable);
- __common_field(unsigned short, padding);
+ __common_field(unsigned char, migrate_disable);
+ __common_field(unsigned char, preempt_lazy_count);
return ret;
}
--
2.36.1
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