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Message-ID: <20100415110948.GF16760@linux.vnet.ibm.com>
Date: Thu, 15 Apr 2010 16:39:48 +0530
From: Arun R Bharadwaj <arun@...ux.vnet.ibm.com>
To: peterz@...radead.org
Cc: Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Ingo Molnar <mingo@...e.hu>,
Vaidyanathan Srinivasan <svaidy@...ux.vnet.ibm.com>,
Dipankar Sarma <dipankar@...ibm.com>,
Balbir Singh <balbir@...ibm.com>,
Arun Bharadwaj <arun@...ux.vnet.ibm.com>,
linux-kernel@...r.kernel.org
Subject: [v12 PATCH 5/8]: pSeries/cpuidle: refactor pseries idle loops.
* Arun R Bharadwaj <arun@...ux.vnet.ibm.com> [2010-04-15 16:30:46]:
This patch removes the routines, pseries_shared_idle_sleep and
pseries_dedicated_idle_sleep, since this is implemented as a part
of arch/powerpc/platform/pseries/processor_idle.c
Also, similar to x86, call cpuidle_idle_call from cpu_idle() idle
loop instead of ppc_md.power_save.
Signed-off-by: Arun R Bharadwaj <arun@...ux.vnet.ibm.com>
---
arch/powerpc/kernel/idle.c | 58 ++++++++++-----------
arch/powerpc/platforms/pseries/setup.c | 89 ---------------------------------
2 files changed, 30 insertions(+), 117 deletions(-)
Index: linux.trees.git/arch/powerpc/platforms/pseries/setup.c
===================================================================
--- linux.trees.git.orig/arch/powerpc/platforms/pseries/setup.c
+++ linux.trees.git/arch/powerpc/platforms/pseries/setup.c
@@ -74,9 +74,6 @@ EXPORT_SYMBOL(CMO_PageSize);
int fwnmi_active; /* TRUE if an FWNMI handler is present */
-static void pseries_shared_idle_sleep(void);
-static void pseries_dedicated_idle_sleep(void);
-
static struct device_node *pSeries_mpic_node;
static void pSeries_show_cpuinfo(struct seq_file *m)
@@ -296,18 +293,8 @@ static void __init pSeries_setup_arch(vo
pSeries_nvram_init();
/* Choose an idle loop */
- if (firmware_has_feature(FW_FEATURE_SPLPAR)) {
+ if (firmware_has_feature(FW_FEATURE_SPLPAR))
vpa_init(boot_cpuid);
- if (get_lppaca()->shared_proc) {
- printk(KERN_DEBUG "Using shared processor idle loop\n");
- ppc_md.power_save = pseries_shared_idle_sleep;
- } else {
- printk(KERN_DEBUG "Using dedicated idle loop\n");
- ppc_md.power_save = pseries_dedicated_idle_sleep;
- }
- } else {
- printk(KERN_DEBUG "Using default idle loop\n");
- }
if (firmware_has_feature(FW_FEATURE_LPAR))
ppc_md.enable_pmcs = pseries_lpar_enable_pmcs;
@@ -495,80 +482,6 @@ static int __init pSeries_probe(void)
return 1;
}
-
-DECLARE_PER_CPU(unsigned long, smt_snooze_delay);
-
-static void pseries_dedicated_idle_sleep(void)
-{
- unsigned int cpu = smp_processor_id();
- unsigned long start_snooze;
- unsigned long in_purr, out_purr;
-
- /*
- * Indicate to the HV that we are idle. Now would be
- * a good time to find other work to dispatch.
- */
- get_lppaca()->idle = 1;
- get_lppaca()->donate_dedicated_cpu = 1;
- in_purr = mfspr(SPRN_PURR);
-
- /*
- * We come in with interrupts disabled, and need_resched()
- * has been checked recently. If we should poll for a little
- * while, do so.
- */
- if (__get_cpu_var(smt_snooze_delay)) {
- start_snooze = get_tb() +
- __get_cpu_var(smt_snooze_delay) * tb_ticks_per_usec;
- local_irq_enable();
- set_thread_flag(TIF_POLLING_NRFLAG);
-
- while (get_tb() < start_snooze) {
- if (need_resched() || cpu_is_offline(cpu))
- goto out;
- ppc64_runlatch_off();
- HMT_low();
- HMT_very_low();
- }
-
- HMT_medium();
- clear_thread_flag(TIF_POLLING_NRFLAG);
- smp_mb();
- local_irq_disable();
- if (need_resched() || cpu_is_offline(cpu))
- goto out;
- }
-
- cede_processor();
-
-out:
- HMT_medium();
- out_purr = mfspr(SPRN_PURR);
- get_lppaca()->wait_state_cycles += out_purr - in_purr;
- get_lppaca()->donate_dedicated_cpu = 0;
- get_lppaca()->idle = 0;
-}
-
-static void pseries_shared_idle_sleep(void)
-{
- /*
- * Indicate to the HV that we are idle. Now would be
- * a good time to find other work to dispatch.
- */
- get_lppaca()->idle = 1;
-
- /*
- * Yield the processor to the hypervisor. We return if
- * an external interrupt occurs (which are driven prior
- * to returning here) or if a prod occurs from another
- * processor. When returning here, external interrupts
- * are enabled.
- */
- cede_processor();
-
- get_lppaca()->idle = 0;
-}
-
static int pSeries_pci_probe_mode(struct pci_bus *bus)
{
if (firmware_has_feature(FW_FEATURE_LPAR))
Index: linux.trees.git/arch/powerpc/kernel/idle.c
===================================================================
--- linux.trees.git.orig/arch/powerpc/kernel/idle.c
+++ linux.trees.git/arch/powerpc/kernel/idle.c
@@ -25,6 +25,7 @@
#include <linux/cpu.h>
#include <linux/sysctl.h>
#include <linux/tick.h>
+#include <linux/cpuidle.h>
#include <asm/system.h>
#include <asm/processor.h>
@@ -46,6 +47,14 @@ static int __init powersave_off(char *ar
}
__setup("powersave=off", powersave_off);
+#ifndef CONFIG_CPU_IDLE
+void cpuidle_idle_call(void)
+{
+ local_irq_enable();
+ cpu_relax();
+}
+#endif
+
/*
* The body of the idle task.
*/
@@ -60,35 +69,26 @@ void cpu_idle(void)
while (!need_resched() && !cpu_should_die()) {
ppc64_runlatch_off();
- if (ppc_md.power_save) {
- clear_thread_flag(TIF_POLLING_NRFLAG);
- /*
- * smp_mb is so clearing of TIF_POLLING_NRFLAG
- * is ordered w.r.t. need_resched() test.
- */
- smp_mb();
- local_irq_disable();
-
- /* Don't trace irqs off for idle */
- stop_critical_timings();
-
- /* check again after disabling irqs */
- if (!need_resched() && !cpu_should_die())
- ppc_md.power_save();
-
- start_critical_timings();
-
- local_irq_enable();
- set_thread_flag(TIF_POLLING_NRFLAG);
-
- } else {
- /*
- * Go into low thread priority and possibly
- * low power mode.
- */
- HMT_low();
- HMT_very_low();
- }
+ clear_thread_flag(TIF_POLLING_NRFLAG);
+ /*
+ * smp_mb is so clearing of TIF_POLLING_NRFLAG
+ * is ordered w.r.t. need_resched() test.
+ */
+ smp_mb();
+ local_irq_disable();
+
+ /* Don't trace irqs off for idle */
+ stop_critical_timings();
+
+ /* check again after disabling irqs */
+ if (!need_resched() && !cpu_should_die())
+ cpuidle_idle_call();
+
+ start_critical_timings();
+
+ local_irq_enable();
+ set_thread_flag(TIF_POLLING_NRFLAG);
+
}
HMT_medium();
--
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