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authorFrederic Weisbecker <fweisbec@gmail.com>2011-10-07 16:22:06 (GMT)
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2011-12-11 18:31:35 (GMT)
commit280f06774afedf849f0b34248ed6aff57d0f6908 (patch)
tree62ef683226d0569c0e6c3ba34ab2e6d85b2e047f /arch
parent867f236bd12f5091df6dc7cc75f94d7fd982d78a (diff)
nohz: Separate out irq exit and idle loop dyntick logic
The tick_nohz_stop_sched_tick() function, which tries to delay the next timer tick as long as possible, can be called from two places: - From the idle loop to start the dytick idle mode - From interrupt exit if we have interrupted the dyntick idle mode, so that we reprogram the next tick event in case the irq changed some internal state that requires this action. There are only few minor differences between both that are handled by that function, driven by the ts->inidle cpu variable and the inidle parameter. The whole guarantees that we only update the dyntick mode on irq exit if we actually interrupted the dyntick idle mode, and that we enter in RCU extended quiescent state from idle loop entry only. Split this function into: - tick_nohz_idle_enter(), which sets ts->inidle to 1, enters dynticks idle mode unconditionally if it can, and enters into RCU extended quiescent state. - tick_nohz_irq_exit() which only updates the dynticks idle mode when ts->inidle is set (ie: if tick_nohz_idle_enter() has been called). To maintain symmetry, tick_nohz_restart_sched_tick() has been renamed into tick_nohz_idle_exit(). This simplifies the code and micro-optimize the irq exit path (no need for local_irq_save there). This also prepares for the split between dynticks and rcu extended quiescent state logics. We'll need this split to further fix illegal uses of RCU in extended quiescent states in the idle loop. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Mike Frysinger <vapier@gentoo.org> Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Cc: David Miller <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Paul Mackerras <paulus@samba.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/arm/kernel/process.c4
-rw-r--r--arch/avr32/kernel/process.c4
-rw-r--r--arch/blackfin/kernel/process.c4
-rw-r--r--arch/microblaze/kernel/process.c4
-rw-r--r--arch/mips/kernel/process.c4
-rw-r--r--arch/openrisc/kernel/idle.c4
-rw-r--r--arch/powerpc/kernel/idle.c4
-rw-r--r--arch/powerpc/platforms/iseries/setup.c8
-rw-r--r--arch/s390/kernel/process.c4
-rw-r--r--arch/sh/kernel/idle.c4
-rw-r--r--arch/sparc/kernel/process_64.c4
-rw-r--r--arch/tile/kernel/process.c4
-rw-r--r--arch/um/kernel/process.c4
-rw-r--r--arch/unicore32/kernel/process.c4
-rw-r--r--arch/x86/kernel/process_32.c4
-rw-r--r--arch/x86/kernel/process_64.c4
16 files changed, 34 insertions, 34 deletions
diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
index 3d0c6fb..3f1f8da 100644
--- a/arch/arm/kernel/process.c
+++ b/arch/arm/kernel/process.c
@@ -183,7 +183,7 @@ void cpu_idle(void)
/* endless idle loop with no priority at all */
while (1) {
- tick_nohz_stop_sched_tick(1);
+ tick_nohz_idle_enter();
leds_event(led_idle_start);
while (!need_resched()) {
#ifdef CONFIG_HOTPLUG_CPU
@@ -213,7 +213,7 @@ void cpu_idle(void)
}
}
leds_event(led_idle_end);
- tick_nohz_restart_sched_tick();
+ tick_nohz_idle_exit();
preempt_enable_no_resched();
schedule();
preempt_disable();
diff --git a/arch/avr32/kernel/process.c b/arch/avr32/kernel/process.c
index ef5a2a0..6ee7952 100644
--- a/arch/avr32/kernel/process.c
+++ b/arch/avr32/kernel/process.c
@@ -34,10 +34,10 @@ void cpu_idle(void)
{
/* endless idle loop with no priority at all */
while (1) {
- tick_nohz_stop_sched_tick(1);
+ tick_nohz_idle_enter();
while (!need_resched())
cpu_idle_sleep();
- tick_nohz_restart_sched_tick();
+ tick_nohz_idle_exit();
preempt_enable_no_resched();
schedule();
preempt_disable();
diff --git a/arch/blackfin/kernel/process.c b/arch/blackfin/kernel/process.c
index 6a80a9e..7b141b5 100644
--- a/arch/blackfin/kernel/process.c
+++ b/arch/blackfin/kernel/process.c
@@ -88,10 +88,10 @@ void cpu_idle(void)
#endif
if (!idle)
idle = default_idle;
- tick_nohz_stop_sched_tick(1);
+ tick_nohz_idle_enter();
while (!need_resched())
idle();
- tick_nohz_restart_sched_tick();
+ tick_nohz_idle_exit();
preempt_enable_no_resched();
schedule();
preempt_disable();
diff --git a/arch/microblaze/kernel/process.c b/arch/microblaze/kernel/process.c
index 95cc295..5407f09 100644
--- a/arch/microblaze/kernel/process.c
+++ b/arch/microblaze/kernel/process.c
@@ -103,10 +103,10 @@ void cpu_idle(void)
if (!idle)
idle = default_idle;
- tick_nohz_stop_sched_tick(1);
+ tick_nohz_idle_enter();
while (!need_resched())
idle();
- tick_nohz_restart_sched_tick();
+ tick_nohz_idle_exit();
preempt_enable_no_resched();
schedule();
diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c
index c47f96e..c11e5ca 100644
--- a/arch/mips/kernel/process.c
+++ b/arch/mips/kernel/process.c
@@ -56,7 +56,7 @@ void __noreturn cpu_idle(void)
/* endless idle loop with no priority at all */
while (1) {
- tick_nohz_stop_sched_tick(1);
+ tick_nohz_idle_enter();
while (!need_resched() && cpu_online(cpu)) {
#ifdef CONFIG_MIPS_MT_SMTC
extern void smtc_idle_loop_hook(void);
@@ -77,7 +77,7 @@ void __noreturn cpu_idle(void)
system_state == SYSTEM_BOOTING))
play_dead();
#endif
- tick_nohz_restart_sched_tick();
+ tick_nohz_idle_exit();
preempt_enable_no_resched();
schedule();
preempt_disable();
diff --git a/arch/openrisc/kernel/idle.c b/arch/openrisc/kernel/idle.c
index d5bc5f8..fb6a9bf 100644
--- a/arch/openrisc/kernel/idle.c
+++ b/arch/openrisc/kernel/idle.c
@@ -51,7 +51,7 @@ void cpu_idle(void)
/* endless idle loop with no priority at all */
while (1) {
- tick_nohz_stop_sched_tick(1);
+ tick_nohz_idle_enter();
while (!need_resched()) {
check_pgt_cache();
@@ -69,7 +69,7 @@ void cpu_idle(void)
set_thread_flag(TIF_POLLING_NRFLAG);
}
- tick_nohz_restart_sched_tick();
+ tick_nohz_idle_exit();
preempt_enable_no_resched();
schedule();
preempt_disable();
diff --git a/arch/powerpc/kernel/idle.c b/arch/powerpc/kernel/idle.c
index 39a2baa..878572f 100644
--- a/arch/powerpc/kernel/idle.c
+++ b/arch/powerpc/kernel/idle.c
@@ -56,7 +56,7 @@ void cpu_idle(void)
set_thread_flag(TIF_POLLING_NRFLAG);
while (1) {
- tick_nohz_stop_sched_tick(1);
+ tick_nohz_idle_enter();
while (!need_resched() && !cpu_should_die()) {
ppc64_runlatch_off();
@@ -93,7 +93,7 @@ void cpu_idle(void)
HMT_medium();
ppc64_runlatch_on();
- tick_nohz_restart_sched_tick();
+ tick_nohz_idle_exit();
preempt_enable_no_resched();
if (cpu_should_die())
cpu_die();
diff --git a/arch/powerpc/platforms/iseries/setup.c b/arch/powerpc/platforms/iseries/setup.c
index ea0acbd..e83dfaf 100644
--- a/arch/powerpc/platforms/iseries/setup.c
+++ b/arch/powerpc/platforms/iseries/setup.c
@@ -563,7 +563,7 @@ static void yield_shared_processor(void)
static void iseries_shared_idle(void)
{
while (1) {
- tick_nohz_stop_sched_tick(1);
+ tick_nohz_idle_enter();
while (!need_resched() && !hvlpevent_is_pending()) {
local_irq_disable();
ppc64_runlatch_off();
@@ -577,7 +577,7 @@ static void iseries_shared_idle(void)
}
ppc64_runlatch_on();
- tick_nohz_restart_sched_tick();
+ tick_nohz_idle_exit();
if (hvlpevent_is_pending())
process_iSeries_events();
@@ -593,7 +593,7 @@ static void iseries_dedicated_idle(void)
set_thread_flag(TIF_POLLING_NRFLAG);
while (1) {
- tick_nohz_stop_sched_tick(1);
+ tick_nohz_idle_enter();
if (!need_resched()) {
while (!need_resched()) {
ppc64_runlatch_off();
@@ -610,7 +610,7 @@ static void iseries_dedicated_idle(void)
}
ppc64_runlatch_on();
- tick_nohz_restart_sched_tick();
+ tick_nohz_idle_exit();
preempt_enable_no_resched();
schedule();
preempt_disable();
diff --git a/arch/s390/kernel/process.c b/arch/s390/kernel/process.c
index 9451b21..6224f9d 100644
--- a/arch/s390/kernel/process.c
+++ b/arch/s390/kernel/process.c
@@ -91,10 +91,10 @@ static void default_idle(void)
void cpu_idle(void)
{
for (;;) {
- tick_nohz_stop_sched_tick(1);
+ tick_nohz_idle_enter();
while (!need_resched())
default_idle();
- tick_nohz_restart_sched_tick();
+ tick_nohz_idle_exit();
preempt_enable_no_resched();
schedule();
preempt_disable();
diff --git a/arch/sh/kernel/idle.c b/arch/sh/kernel/idle.c
index db4ecd7..6015743 100644
--- a/arch/sh/kernel/idle.c
+++ b/arch/sh/kernel/idle.c
@@ -89,7 +89,7 @@ void cpu_idle(void)
/* endless idle loop with no priority at all */
while (1) {
- tick_nohz_stop_sched_tick(1);
+ tick_nohz_idle_enter();
while (!need_resched()) {
check_pgt_cache();
@@ -111,7 +111,7 @@ void cpu_idle(void)
start_critical_timings();
}
- tick_nohz_restart_sched_tick();
+ tick_nohz_idle_exit();
preempt_enable_no_resched();
schedule();
preempt_disable();
diff --git a/arch/sparc/kernel/process_64.c b/arch/sparc/kernel/process_64.c
index 3739a06..9c2795b 100644
--- a/arch/sparc/kernel/process_64.c
+++ b/arch/sparc/kernel/process_64.c
@@ -95,12 +95,12 @@ void cpu_idle(void)
set_thread_flag(TIF_POLLING_NRFLAG);
while(1) {
- tick_nohz_stop_sched_tick(1);
+ tick_nohz_idle_enter();
while (!need_resched() && !cpu_is_offline(cpu))
sparc64_yield(cpu);
- tick_nohz_restart_sched_tick();
+ tick_nohz_idle_exit();
preempt_enable_no_resched();
diff --git a/arch/tile/kernel/process.c b/arch/tile/kernel/process.c
index 9c45d8b..920e674 100644
--- a/arch/tile/kernel/process.c
+++ b/arch/tile/kernel/process.c
@@ -85,7 +85,7 @@ void cpu_idle(void)
/* endless idle loop with no priority at all */
while (1) {
- tick_nohz_stop_sched_tick(1);
+ tick_nohz_idle_enter();
while (!need_resched()) {
if (cpu_is_offline(cpu))
BUG(); /* no HOTPLUG_CPU */
@@ -105,7 +105,7 @@ void cpu_idle(void)
local_irq_enable();
current_thread_info()->status |= TS_POLLING;
}
- tick_nohz_restart_sched_tick();
+ tick_nohz_idle_exit();
preempt_enable_no_resched();
schedule();
preempt_disable();
diff --git a/arch/um/kernel/process.c b/arch/um/kernel/process.c
index c533835..cfb657e 100644
--- a/arch/um/kernel/process.c
+++ b/arch/um/kernel/process.c
@@ -246,10 +246,10 @@ void default_idle(void)
if (need_resched())
schedule();
- tick_nohz_stop_sched_tick(1);
+ tick_nohz_idle_enter();
nsecs = disable_timer();
idle_sleep(nsecs);
- tick_nohz_restart_sched_tick();
+ tick_nohz_idle_exit();
}
}
diff --git a/arch/unicore32/kernel/process.c b/arch/unicore32/kernel/process.c
index ba401df..9999b9a 100644
--- a/arch/unicore32/kernel/process.c
+++ b/arch/unicore32/kernel/process.c
@@ -55,7 +55,7 @@ void cpu_idle(void)
{
/* endless idle loop with no priority at all */
while (1) {
- tick_nohz_stop_sched_tick(1);
+ tick_nohz_idle_enter();
while (!need_resched()) {
local_irq_disable();
stop_critical_timings();
@@ -63,7 +63,7 @@ void cpu_idle(void)
local_irq_enable();
start_critical_timings();
}
- tick_nohz_restart_sched_tick();
+ tick_nohz_idle_exit();
preempt_enable_no_resched();
schedule();
preempt_disable();
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index 795b79f..6d9d4d5 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -99,7 +99,7 @@ void cpu_idle(void)
/* endless idle loop with no priority at all */
while (1) {
- tick_nohz_stop_sched_tick(1);
+ tick_nohz_idle_enter();
while (!need_resched()) {
check_pgt_cache();
@@ -116,7 +116,7 @@ void cpu_idle(void)
pm_idle();
start_critical_timings();
}
- tick_nohz_restart_sched_tick();
+ tick_nohz_idle_exit();
preempt_enable_no_resched();
schedule();
preempt_disable();
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 3bd7e6e..b069e9d 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -122,7 +122,7 @@ void cpu_idle(void)
/* endless idle loop with no priority at all */
while (1) {
- tick_nohz_stop_sched_tick(1);
+ tick_nohz_idle_enter();
while (!need_resched()) {
rmb();
@@ -149,7 +149,7 @@ void cpu_idle(void)
__exit_idle();
}
- tick_nohz_restart_sched_tick();
+ tick_nohz_idle_exit();
preempt_enable_no_resched();
schedule();
preempt_disable();

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