Re: [PATCH] i386 No Idle HZ aka dynticks v051205

[Dominik Brodowski <linux-X3ehHDuj6sIIGcDfoQAp7OTW4wlIGRCZ@public.gmane.org>]

Hi,

Please merge this patch also into your dyntick patchset. Upon further
refleciton, we shouldn't be _this_ aggressive to enter C3-type sleep if
there was bus mastering activity this jiffy.

Signed-off-by: Dominik Brodowski	<linux-X3ehHDuj6sIIGcDfoQAp7OTW4wlIGRCZ@public.gmane.org>

Index: working-tree/drivers/acpi/processor_idle.c
===================================================================
--- working-tree.orig/drivers/acpi/processor_idle.c
+++ working-tree/drivers/acpi/processor_idle.c
@@ -260,7 +260,7 @@ static void acpi_processor_idle(void)
 		pr->power.bm_check_timestamp = jiffies;
 
 		/*
-		 * If bus mastering is active, automatically demote
+		 * If bus mastering is or was active this jiffy, demote
 		 * to avoid a faulty transition.  Note that the processor
 		 * won't enter a low-power state during this call (to this
 		 * function) but should upon the next.
@@ -271,7 +271,8 @@ static void acpi_processor_idle(void)
 		 *      qualification.  This may, however, introduce DMA
 		 *      issues (e.g. floppy DMA transfer overrun/underrun).
 		 */
-		if (bm_status && cx->demotion.threshold.bm) {
+		if ((pr->power.bm_activity & 0x01) &&
+		    cx->demotion.threshold.bm) {
 			local_irq_enable();
 			next_state = cx->demotion.state;
 			if (dyn_tick_enabled())


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