linux-kernel - [tip:x86/apic] x86/smp: Remove pointless duplicated interrupt code

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Message-ID: <tip-85b77cdd8fbd163d65f340e3f6578c50031af960@git.kernel.org>
Date:   Tue, 29 Aug 2017 04:09:17 -0700
From:   tip-bot for Thomas Gleixner <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     peterz@...radead.org, hpa@...or.com, tglx@...utronix.de,
        linux-kernel@...r.kernel.org, rostedt@...dmis.org, luto@...nel.org,
        bp@...en8.de, torvalds@...ux-foundation.org, mingo@...nel.org
Subject: [tip:x86/apic] x86/smp: Remove pointless duplicated interrupt code

Commit-ID:  85b77cdd8fbd163d65f340e3f6578c50031af960
Gitweb:     http://git.kernel.org/tip/85b77cdd8fbd163d65f340e3f6578c50031af960
Author:     Thomas Gleixner <tglx@...utronix.de>
AuthorDate: Mon, 28 Aug 2017 08:47:29 +0200
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Tue, 29 Aug 2017 11:42:27 +0200

x86/smp: Remove pointless duplicated interrupt code

Two NOP5s are really a good tradeoff vs. the unholy IDT switching mess,
which duplicates code all over the place. The rescheduling interrupt gets
optimized in a later step.

Make the ordering of function call and statistics increment the same as in
other places. Calculate stats first, then do the function call.

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
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>
Cc: Steven Rostedt <rostedt@...dmis.org>
Link: http://lkml.kernel.org/r/20170828064957.222101344@linutronix.de
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 arch/x86/include/asm/hw_irq.h |  4 ++--
 arch/x86/kernel/smp.c         | 43 +++++++------------------------------------
 2 files changed, 9 insertions(+), 38 deletions(-)

diff --git a/arch/x86/include/asm/hw_irq.h b/arch/x86/include/asm/hw_irq.h
index 5f042ec..8fb6c22 100644
--- a/arch/x86/include/asm/hw_irq.h
+++ b/arch/x86/include/asm/hw_irq.h
@@ -49,8 +49,8 @@ extern asmlinkage void call_function_single_interrupt(void);
 #ifdef CONFIG_TRACING
 /* Interrupt handlers registered during init_IRQ */
 extern void trace_reschedule_interrupt(void);
-extern void trace_call_function_interrupt(void);
-extern void trace_call_function_single_interrupt(void);
+#define trace_call_function_interrupt	call_function_interrupt
+#define trace_call_function_single_interrupt	call_function_single_interrupt
 #define trace_thermal_interrupt	thermal_interrupt
 #define trace_threshold_interrupt	threshold_interrupt
 #define trace_deferred_error_interrupt	deferred_error_interrupt
diff --git a/arch/x86/kernel/smp.c b/arch/x86/kernel/smp.c
index d798c0d..fb49e10 100644
--- a/arch/x86/kernel/smp.c
+++ b/arch/x86/kernel/smp.c
@@ -281,57 +281,28 @@ __visible void __irq_entry smp_trace_reschedule_interrupt(struct pt_regs *regs)
 	 */
 	ipi_entering_ack_irq();
 	trace_reschedule_entry(RESCHEDULE_VECTOR);
-	__smp_reschedule_interrupt();
+	inc_irq_stat(irq_resched_count);
+	scheduler_ipi();
 	trace_reschedule_exit(RESCHEDULE_VECTOR);
 	exiting_irq();
-	/*
-	 * KVM uses this interrupt to force a cpu out of guest mode
-	 */
-}
-
-static inline void __smp_call_function_interrupt(void)
-{
-	generic_smp_call_function_interrupt();
-	inc_irq_stat(irq_call_count);
 }
 
 __visible void __irq_entry smp_call_function_interrupt(struct pt_regs *regs)
 {
 	ipi_entering_ack_irq();
-	__smp_call_function_interrupt();
-	exiting_irq();
-}
-
-__visible void __irq_entry
-smp_trace_call_function_interrupt(struct pt_regs *regs)
-{
-	ipi_entering_ack_irq();
 	trace_call_function_entry(CALL_FUNCTION_VECTOR);
-	__smp_call_function_interrupt();
-	trace_call_function_exit(CALL_FUNCTION_VECTOR);
-	exiting_irq();
-}
-
-static inline void __smp_call_function_single_interrupt(void)
-{
-	generic_smp_call_function_single_interrupt();
 	inc_irq_stat(irq_call_count);
-}
-
-__visible void __irq_entry
-smp_call_function_single_interrupt(struct pt_regs *regs)
-{
-	ipi_entering_ack_irq();
-	__smp_call_function_single_interrupt();
+	generic_smp_call_function_interrupt();
+	trace_call_function_exit(CALL_FUNCTION_VECTOR);
 	exiting_irq();
 }
 
-__visible void __irq_entry
-smp_trace_call_function_single_interrupt(struct pt_regs *regs)
+__visible void __irq_entry smp_call_function_single_interrupt(struct pt_regs *r)
 {
 	ipi_entering_ack_irq();
 	trace_call_function_single_entry(CALL_FUNCTION_SINGLE_VECTOR);
-	__smp_call_function_single_interrupt();
+	inc_irq_stat(irq_call_count);
+	generic_smp_call_function_single_interrupt();
 	trace_call_function_single_exit(CALL_FUNCTION_SINGLE_VECTOR);
 	exiting_irq();
 }