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sched/idle, PPC: Remove redundant cpuidle_idle_call() 

The core idle loop now takes care of it.  However a few things need
checking:

- Invocation of cpuidle_idle_call() in pseries_lpar_idle() happened
  through arch_cpu_idle() and was therefore always preceded by a call
  to ppc64_runlatch_off().  To preserve this property now that
  cpuidle_idle_call() is invoked directly from core code, a call to
  ppc64_runlatch_off() has been added to idle_loop_prolog() in
  platforms/pseries/processor_idle.c.

- Similarly, cpuidle_idle_call() was followed by ppc64_runlatch_off()
  so a call to the later has been added to idle_loop_epilog().

- And since arch_cpu_idle() always made sure to re-enable IRQs if they
  were not enabled, this is now
  done in idle_loop_epilog() as well.

The above was made in order to keep the execution flow close to the
original.  I don't know if that was strictly necessary. Someone well
aquainted with the platform details might find some room for possible
optimizations.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
Reviewed-by: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-sh@vger.kernel.org
Cc: linux-pm@vger.kernel.org
Cc: Russell King <linux@arm.linux.org.uk>
Cc: linaro-kernel@lists.linaro.org
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/n/tip-47o4m03citrfg9y1vxic5asb@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Nicolas Pitre 2014-01-29 12:45:10 -05:00 committed by Ingo Molnar
parent ad68cc7a77
commit d8c6ad3184
2 changed files with 19 additions and 20 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

34
arch/powerpc/platforms/pseries/setup.c
View File

@ -39,7 +39,6 @@
#include <linux/irq.h> #include <linux/irq.h>
#include <linux/seq_file.h> #include <linux/seq_file.h>
#include <linux/root_dev.h> #include <linux/root_dev.h>
#include <linux/cpuidle.h>
#include <linux/of.h> #include <linux/of.h>
#include <linux/kexec.h> #include <linux/kexec.h>
@ -356,29 +355,24 @@ early_initcall(alloc_dispatch_log_kmem_cache);
static void pseries_lpar_idle(void) static void pseries_lpar_idle(void)
{ {
/* This would call on the cpuidle framework, and the back-end pseries /*
* driver to go to idle states * Default handler to go into low thread priority and possibly
* low power mode by cedeing processor to hypervisor
*/ */
if (cpuidle_idle_call()) {
/* On error, execute default handler
* to go into low thread priority and possibly
* low power mode by cedeing processor to hypervisor
*/
/* Indicate to hypervisor that we are idle. */ /* Indicate to hypervisor that we are idle. */
get_lppaca()->idle = 1; get_lppaca()->idle = 1;
/* /*
* Yield the processor to the hypervisor. We return if * Yield the processor to the hypervisor. We return if
* an external interrupt occurs (which are driven prior * an external interrupt occurs (which are driven prior
* to returning here) or if a prod occurs from another * to returning here) or if a prod occurs from another
* processor. When returning here, external interrupts * processor. When returning here, external interrupts
* are enabled. * are enabled.
*/ */
cede_processor(); cede_processor();
get_lppaca()->idle = 0; get_lppaca()->idle = 0;
}
} }
/* /*

5
drivers/cpuidle/cpuidle-pseries.c
View File

@ -29,6 +29,7 @@ static struct cpuidle_state *cpuidle_state_table;
static inline void idle_loop_prolog(unsigned long *in_purr) static inline void idle_loop_prolog(unsigned long *in_purr)
{ {
ppc64_runlatch_off();
*in_purr = mfspr(SPRN_PURR); *in_purr = mfspr(SPRN_PURR);
/* /*
* Indicate to the HV that we are idle. Now would be * Indicate to the HV that we are idle. Now would be
@ -45,6 +46,10 @@ static inline void idle_loop_epilog(unsigned long in_purr)
wait_cycles += mfspr(SPRN_PURR) - in_purr; wait_cycles += mfspr(SPRN_PURR) - in_purr;
get_lppaca()->wait_state_cycles = cpu_to_be64(wait_cycles); get_lppaca()->wait_state_cycles = cpu_to_be64(wait_cycles);
get_lppaca()->idle = 0; get_lppaca()->idle = 0;
if (irqs_disabled())
local_irq_enable();
ppc64_runlatch_on();
} }
static int snooze_loop(struct cpuidle_device *dev, static int snooze_loop(struct cpuidle_device *dev,