linux-kernel - [tip:x86/apic] x86/apic: Remove the duplicated tracing version of local_timer

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Date:   Tue, 29 Aug 2017 04:07:02 -0700
From:   tip-bot for Thomas Gleixner <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     mingo@...nel.org, bp@...en8.de, linux-kernel@...r.kernel.org,
        luto@...nel.org, tglx@...utronix.de, rostedt@...dmis.org,
        torvalds@...ux-foundation.org, peterz@...radead.org, hpa@...or.com
Subject: [tip:x86/apic] x86/apic: Remove the duplicated tracing version of
 local_timer_interrupt()

Commit-ID:  302a98f896bbd2feb1393d98e8b9febeb101db6e
Gitweb:     http://git.kernel.org/tip/302a98f896bbd2feb1393d98e8b9febeb101db6e
Author:     Thomas Gleixner <tglx@...utronix.de>
AuthorDate: Mon, 28 Aug 2017 08:47:23 +0200
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Tue, 29 Aug 2017 11:42:24 +0200

x86/apic: Remove the duplicated tracing version of local_timer_interrupt()

The two NOP5s are noise in the rest of the work which is done by the timer
interrupt and modern CPUs are pretty good in optimizing NOPs anyway.

Get rid of the interrupt handler duplication and move the tracepoints into
the regular handler.

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Reviewed-by: Steven Rostedt (VMware) <rostedt@...dmis.org>
Cc: Andy Lutomirski <luto@...nel.org>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Link: http://lkml.kernel.org/r/20170828064956.751247330@linutronix.de
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 arch/x86/include/asm/hw_irq.h |  2 +-
 arch/x86/kernel/apic/apic.c   | 19 -------------------
 2 files changed, 1 insertion(+), 20 deletions(-)

diff --git a/arch/x86/include/asm/hw_irq.h b/arch/x86/include/asm/hw_irq.h
index d6dbafb..44137bb 100644
--- a/arch/x86/include/asm/hw_irq.h
+++ b/arch/x86/include/asm/hw_irq.h
@@ -48,7 +48,6 @@ extern asmlinkage void call_function_single_interrupt(void);
 
 #ifdef CONFIG_TRACING
 /* Interrupt handlers registered during init_IRQ */
-extern void trace_apic_timer_interrupt(void);
 extern void trace_x86_platform_ipi(void);
 extern void trace_error_interrupt(void);
 extern void trace_irq_work_interrupt(void);
@@ -59,6 +58,7 @@ extern void trace_threshold_interrupt(void);
 extern void trace_deferred_error_interrupt(void);
 extern void trace_call_function_interrupt(void);
 extern void trace_call_function_single_interrupt(void);
+#define trace_apic_timer_interrupt	apic_timer_interrupt
 #define trace_irq_move_cleanup_interrupt  irq_move_cleanup_interrupt
 #define trace_reboot_interrupt  reboot_interrupt
 #define trace_kvm_posted_intr_ipi kvm_posted_intr_ipi
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index 8996ef1..7a57b54 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -1038,25 +1038,6 @@ __visible void __irq_entry smp_apic_timer_interrupt(struct pt_regs *regs)
 	 * interrupt lock, which is the WrongThing (tm) to do.
 	 */
 	entering_ack_irq();
-	local_apic_timer_interrupt();
-	exiting_irq();
-
-	set_irq_regs(old_regs);
-}
-
-__visible void __irq_entry smp_trace_apic_timer_interrupt(struct pt_regs *regs)
-{
-	struct pt_regs *old_regs = set_irq_regs(regs);
-
-	/*
-	 * NOTE! We'd better ACK the irq immediately,
-	 * because timer handling can be slow.
-	 *
-	 * update_process_times() expects us to have done irq_enter().
-	 * Besides, if we don't timer interrupts ignore the global
-	 * interrupt lock, which is the WrongThing (tm) to do.
-	 */
-	entering_ack_irq();
 	trace_local_timer_entry(LOCAL_TIMER_VECTOR);
 	local_apic_timer_interrupt();
 	trace_local_timer_exit(LOCAL_TIMER_VECTOR);