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nmi_backtrace: generate one-line reports for idle cpus
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When doing an nmi backtrace of many cores, most of which are idle, the
output is a little overwhelming and very uninformative.  Suppress
messages for cpus that are idling when they are interrupted and just
emit one line, "NMI backtrace for N skipped: idling at pc 0xNNN".

We do this by grouping all the cpuidle code together into a new
.cpuidle.text section, and then checking the address of the interrupted
PC to see if it lies within that section.

This commit suitably tags x86 and tile idle routines, and only adds in
the minimal framework for other architectures.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Chris Metcalf <[email protected]>
Acked-by: Peter Zijlstra (Intel) <[email protected]>
Tested-by: Peter Zijlstra (Intel) <[email protected]>
Tested-by: Daniel Thompson <[email protected]> [arm]
Tested-by: Petr Mladek <[email protected]>
Cc: Aaron Tomlin <[email protected]>
Cc: Peter Zijlstra (Intel) <[email protected]>
Cc: "Rafael J. Wysocki" <[email protected]>
Cc: Russell King <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Ingo Molnar <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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@cmetcalf-tilera @torvalds
cmetcalf-tilera authored and torvalds committed Oct 8, 2016
1 parent 511f838 commit 6727ad9
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Showing 49 changed files with 93 additions and 22 deletions.
1 change: 1 addition & 0 deletions arch/alpha/kernel/vmlinux.lds.S
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HEAD_TEXT
TEXT_TEXT
SCHED_TEXT
CPUIDLE_TEXT
LOCK_TEXT
*(.fixup)
*(.gnu.warning)
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1 change: 1 addition & 0 deletions arch/arc/kernel/vmlinux.lds.S
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_text = .;
TEXT_TEXT
SCHED_TEXT
CPUIDLE_TEXT
LOCK_TEXT
KPROBES_TEXT
*(.fixup)
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1 change: 1 addition & 0 deletions arch/arm/kernel/vmlinux-xip.lds.S
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IRQENTRY_TEXT
TEXT_TEXT
SCHED_TEXT
CPUIDLE_TEXT
LOCK_TEXT
KPROBES_TEXT
*(.gnu.warning)
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1 change: 1 addition & 0 deletions arch/arm/kernel/vmlinux.lds.S
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SOFTIRQENTRY_TEXT
TEXT_TEXT
SCHED_TEXT
CPUIDLE_TEXT
LOCK_TEXT
HYPERVISOR_TEXT
KPROBES_TEXT
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1 change: 1 addition & 0 deletions arch/arm64/kernel/vmlinux.lds.S
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ENTRY_TEXT
TEXT_TEXT
SCHED_TEXT
CPUIDLE_TEXT
LOCK_TEXT
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HYPERVISOR_TEXT
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1 change: 1 addition & 0 deletions arch/avr32/kernel/vmlinux.lds.S
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KPROBES_TEXT
TEXT_TEXT
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*(.fixup)
*(.gnu.warning)
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1 change: 1 addition & 0 deletions arch/blackfin/kernel/vmlinux.lds.S
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#ifndef CONFIG_SCHEDULE_L1
SCHED_TEXT
#endif
CPUIDLE_TEXT
LOCK_TEXT
IRQENTRY_TEXT
SOFTIRQENTRY_TEXT
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1 change: 1 addition & 0 deletions arch/c6x/kernel/vmlinux.lds.S
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_stext = .;
TEXT_TEXT
SCHED_TEXT
CPUIDLE_TEXT
LOCK_TEXT
IRQENTRY_TEXT
SOFTIRQENTRY_TEXT
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1 change: 1 addition & 0 deletions arch/cris/kernel/vmlinux.lds.S
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HEAD_TEXT
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*(.fixup)
*(.text.__*)
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1 change: 1 addition & 0 deletions arch/frv/kernel/vmlinux.lds.S
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*(.text..tlbmiss)
TEXT_TEXT
SCHED_TEXT
CPUIDLE_TEXT
LOCK_TEXT
#ifdef CONFIG_DEBUG_INFO
INIT_TEXT
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1 change: 1 addition & 0 deletions arch/h8300/kernel/vmlinux.lds.S
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_stext = . ;
TEXT_TEXT
SCHED_TEXT
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LOCK_TEXT
#if defined(CONFIG_ROMKERNEL)
*(.int_redirect)
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1 change: 1 addition & 0 deletions arch/hexagon/kernel/vmlinux.lds.S
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_text = .;
TEXT_TEXT
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*(.fixup)
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1 change: 1 addition & 0 deletions arch/ia64/kernel/vmlinux.lds.S
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Expand Up @@ -46,6 +46,7 @@ SECTIONS {
__end_ivt_text = .;
TEXT_TEXT
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*(.gnu.linkonce.t*)
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1 change: 1 addition & 0 deletions arch/m32r/kernel/vmlinux.lds.S
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HEAD_TEXT
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*(.fixup)
*(.gnu.warning)
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1 change: 1 addition & 0 deletions arch/m68k/kernel/vmlinux-nommu.lds
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HEAD_TEXT
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*(.fixup)
. = ALIGN(16);
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1 change: 1 addition & 0 deletions arch/m68k/kernel/vmlinux-std.lds
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HEAD_TEXT
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*(.fixup)
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1 change: 1 addition & 0 deletions arch/m68k/kernel/vmlinux-sun3.lds
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HEAD_TEXT
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1 change: 1 addition & 0 deletions arch/metag/kernel/vmlinux.lds.S
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.text : {
TEXT_TEXT
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1 change: 1 addition & 0 deletions arch/microblaze/kernel/vmlinux.lds.S
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EXIT_TEXT
EXIT_CALL
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IRQENTRY_TEXT
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1 change: 1 addition & 0 deletions arch/mips/kernel/vmlinux.lds.S
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.text : {
TEXT_TEXT
SCHED_TEXT
CPUIDLE_TEXT
LOCK_TEXT
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IRQENTRY_TEXT
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1 change: 1 addition & 0 deletions arch/mn10300/kernel/vmlinux.lds.S
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HEAD_TEXT
TEXT_TEXT
SCHED_TEXT
CPUIDLE_TEXT
LOCK_TEXT
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*(.fixup)
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1 change: 1 addition & 0 deletions arch/nios2/kernel/vmlinux.lds.S
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.text : {
TEXT_TEXT
SCHED_TEXT
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IRQENTRY_TEXT
SOFTIRQENTRY_TEXT
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1 change: 1 addition & 0 deletions arch/openrisc/kernel/vmlinux.lds.S
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_stext = .;
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1 change: 1 addition & 0 deletions arch/parisc/kernel/vmlinux.lds.S
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.text ALIGN(PAGE_SIZE) : {
TEXT_TEXT
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1 change: 1 addition & 0 deletions arch/powerpc/kernel/vmlinux.lds.S
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/* careful! __ftr_alt_* sections need to be close to .text */
*(.text .fixup __ftr_alt_* .ref.text)
SCHED_TEXT
CPUIDLE_TEXT
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KPROBES_TEXT
IRQENTRY_TEXT
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1 change: 1 addition & 0 deletions arch/s390/kernel/vmlinux.lds.S
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1 change: 1 addition & 0 deletions arch/score/kernel/vmlinux.lds.S
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_text = .; /* Text and read-only data */
TEXT_TEXT
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LOCK_TEXT
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*(.text.*)
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1 change: 1 addition & 0 deletions arch/sh/kernel/vmlinux.lds.S
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TEXT_TEXT
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1 change: 1 addition & 0 deletions arch/sparc/kernel/vmlinux.lds.S
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HEAD_TEXT
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2 changes: 1 addition & 1 deletion arch/tile/kernel/entry.S
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Expand Up @@ -50,7 +50,7 @@ STD_ENTRY(smp_nap)
* When interrupted at _cpu_idle_nap, we bump the PC forward 8, and
* as a result return to the function that called _cpu_idle().
*/
STD_ENTRY(_cpu_idle)
STD_ENTRY_SECTION(_cpu_idle, .cpuidle.text)
movei r1, 1
IRQ_ENABLE_LOAD(r2, r3)
mtspr INTERRUPT_CRITICAL_SECTION, r1
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1 change: 1 addition & 0 deletions arch/tile/kernel/vmlinux.lds.S
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.text : AT (ADDR(.text) - LOAD_OFFSET) {
HEAD_TEXT
SCHED_TEXT
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LOCK_TEXT
KPROBES_TEXT
IRQENTRY_TEXT
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1 change: 1 addition & 0 deletions arch/um/kernel/dyn.lds.S
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_stext = .;
TEXT_TEXT
SCHED_TEXT
CPUIDLE_TEXT
LOCK_TEXT
*(.fixup)
*(.stub .text.* .gnu.linkonce.t.*)
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1 change: 1 addition & 0 deletions arch/um/kernel/uml.lds.S
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_stext = .;
TEXT_TEXT
SCHED_TEXT
CPUIDLE_TEXT
LOCK_TEXT
*(.fixup)
/* .gnu.warning sections are handled specially by elf32.em. */
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1 change: 1 addition & 0 deletions arch/unicore32/kernel/vmlinux.lds.S
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.text : { /* Real text segment */
TEXT_TEXT
SCHED_TEXT
CPUIDLE_TEXT
LOCK_TEXT

*(.fixup)
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12 changes: 8 additions & 4 deletions arch/x86/include/asm/irqflags.h
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Expand Up @@ -4,6 +4,10 @@
#include <asm/processor-flags.h>

#ifndef __ASSEMBLY__

/* Provide __cpuidle; we can't safely include <linux/cpu.h> */
#define __cpuidle __attribute__((__section__(".cpuidle.text")))

/*
* Interrupt control:
*/
Expand Down Expand Up @@ -44,12 +48,12 @@ static inline void native_irq_enable(void)
asm volatile("sti": : :"memory");
}

static inline void native_safe_halt(void)
static inline __cpuidle void native_safe_halt(void)
{
asm volatile("sti; hlt": : :"memory");
}

static inline void native_halt(void)
static inline __cpuidle void native_halt(void)
{
asm volatile("hlt": : :"memory");
}
Expand Down Expand Up @@ -86,7 +90,7 @@ static inline notrace void arch_local_irq_enable(void)
* Used in the idle loop; sti takes one instruction cycle
* to complete:
*/
static inline void arch_safe_halt(void)
static inline __cpuidle void arch_safe_halt(void)
{
native_safe_halt();
}
Expand All @@ -95,7 +99,7 @@ static inline void arch_safe_halt(void)
* Used when interrupts are already enabled or to
* shutdown the processor:
*/
static inline void halt(void)
static inline __cpuidle void halt(void)
{
native_halt();
}
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2 changes: 1 addition & 1 deletion arch/x86/kernel/acpi/cstate.c
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Expand Up @@ -152,7 +152,7 @@ int acpi_processor_ffh_cstate_probe(unsigned int cpu,
}
EXPORT_SYMBOL_GPL(acpi_processor_ffh_cstate_probe);

void acpi_processor_ffh_cstate_enter(struct acpi_processor_cx *cx)
void __cpuidle acpi_processor_ffh_cstate_enter(struct acpi_processor_cx *cx)
{
unsigned int cpu = smp_processor_id();
struct cstate_entry *percpu_entry;
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4 changes: 2 additions & 2 deletions arch/x86/kernel/process.c
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Expand Up @@ -302,7 +302,7 @@ void arch_cpu_idle(void)
/*
* We use this if we don't have any better idle routine..
*/
void default_idle(void)
void __cpuidle default_idle(void)
{
trace_cpu_idle_rcuidle(1, smp_processor_id());
safe_halt();
Expand Down Expand Up @@ -417,7 +417,7 @@ static int prefer_mwait_c1_over_halt(const struct cpuinfo_x86 *c)
* with interrupts enabled and no flags, which is backwards compatible with the
* original MWAIT implementation.
*/
static void mwait_idle(void)
static __cpuidle void mwait_idle(void)
{
if (!current_set_polling_and_test()) {
trace_cpu_idle_rcuidle(1, smp_processor_id());
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1 change: 1 addition & 0 deletions arch/x86/kernel/vmlinux.lds.S
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Expand Up @@ -97,6 +97,7 @@ SECTIONS
_stext = .;
TEXT_TEXT
SCHED_TEXT
CPUIDLE_TEXT
LOCK_TEXT
KPROBES_TEXT
ENTRY_TEXT
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3 changes: 3 additions & 0 deletions arch/xtensa/kernel/vmlinux.lds.S
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Expand Up @@ -89,6 +89,9 @@ SECTIONS
VMLINUX_SYMBOL(__sched_text_start) = .;
*(.sched.literal .sched.text)
VMLINUX_SYMBOL(__sched_text_end) = .;
VMLINUX_SYMBOL(__cpuidle_text_start) = .;
*(.cpuidle.literal .cpuidle.text)
VMLINUX_SYMBOL(__cpuidle_text_end) = .;
VMLINUX_SYMBOL(__lock_text_start) = .;
*(.spinlock.literal .spinlock.text)
VMLINUX_SYMBOL(__lock_text_end) = .;
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5 changes: 3 additions & 2 deletions drivers/acpi/processor_idle.c
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Expand Up @@ -31,6 +31,7 @@
#include <linux/sched.h> /* need_resched() */
#include <linux/tick.h>
#include <linux/cpuidle.h>
#include <linux/cpu.h>
#include <acpi/processor.h>

/*
Expand Down Expand Up @@ -115,7 +116,7 @@ static const struct dmi_system_id processor_power_dmi_table[] = {
* Callers should disable interrupts before the call and enable
* interrupts after return.
*/
static void acpi_safe_halt(void)
static void __cpuidle acpi_safe_halt(void)
{
if (!tif_need_resched()) {
safe_halt();
Expand Down Expand Up @@ -645,7 +646,7 @@ static int acpi_idle_bm_check(void)
*
* Caller disables interrupt before call and enables interrupt after return.
*/
static void acpi_idle_do_entry(struct acpi_processor_cx *cx)
static void __cpuidle acpi_idle_do_entry(struct acpi_processor_cx *cx)
{
if (cx->entry_method == ACPI_CSTATE_FFH) {
/* Call into architectural FFH based C-state */
Expand Down
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