From 06027bdd278a32a84b273e41db68a5db8ffd2bb6 Mon Sep 17 00:00:00 2001
From: Ingo Molnar <mingo@elte.hu>
Date: Tue, 14 Feb 2006 13:53:15 -0800
Subject: [PATCH] [PATCH] hrtimer: round up relative start time on low-res
arches
CONFIG_TIME_LOW_RES is a temporary way for architectures to signal that
they simply return xtime in do_gettimeoffset(). In this corner-case we
want to round up by resolution when starting a relative timer, to avoid
short timeouts. This will go away with the GTOD framework.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Roman Zippel <zippel@linux-m68k.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---
arch/frv/Kconfig | 4 ++++
arch/h8300/Kconfig | 4 ++++
arch/m68k/Kconfig | 4 ++++
arch/m68knommu/Kconfig | 4 ++++
arch/parisc/Kconfig | 5 +++++
arch/v850/Kconfig | 4 ++++
kernel/hrtimer.c | 13 ++++++++++++-
7 files changed, 37 insertions(+), 1 deletion(-)
diff --git a/arch/frv/Kconfig b/arch/frv/Kconfig
index 60a617aff8ba46..e0838371237093 100644
--- a/arch/frv/Kconfig
+++ b/arch/frv/Kconfig
@@ -25,6 +25,10 @@ config GENERIC_HARDIRQS
bool
default n
+config TIME_LOW_RES
+ bool
+ default y
+
mainmenu "Fujitsu FR-V Kernel Configuration"
source "init/Kconfig"
diff --git a/arch/h8300/Kconfig b/arch/h8300/Kconfig
index 80940d712acf76..98308b018a3514 100644
--- a/arch/h8300/Kconfig
+++ b/arch/h8300/Kconfig
@@ -33,6 +33,10 @@ config GENERIC_CALIBRATE_DELAY
bool
default y
+config TIME_LOW_RES
+ bool
+ default y
+
config ISA
bool
default y
diff --git a/arch/m68k/Kconfig b/arch/m68k/Kconfig
index 96b91982805316..8849439e88dd35 100644
--- a/arch/m68k/Kconfig
+++ b/arch/m68k/Kconfig
@@ -21,6 +21,10 @@ config GENERIC_CALIBRATE_DELAY
bool
default y
+config TIME_LOW_RES
+ bool
+ default y
+
config ARCH_MAY_HAVE_PC_FDC
bool
depends on Q40 || (BROKEN && SUN3X)
diff --git a/arch/m68knommu/Kconfig b/arch/m68knommu/Kconfig
index e2a6e864896080..e50858dbc23777 100644
--- a/arch/m68knommu/Kconfig
+++ b/arch/m68knommu/Kconfig
@@ -29,6 +29,10 @@ config GENERIC_CALIBRATE_DELAY
bool
default y
+config TIME_LOW_RES
+ bool
+ default y
+
source "init/Kconfig"
menu "Processor type and features"
diff --git a/arch/parisc/Kconfig b/arch/parisc/Kconfig
index 7c914a4c67c3e9..eca33cfa8a4c5d 100644
--- a/arch/parisc/Kconfig
+++ b/arch/parisc/Kconfig
@@ -29,6 +29,11 @@ config GENERIC_CALIBRATE_DELAY
bool
default y
+config TIME_LOW_RES
+ bool
+ depends on SMP
+ default y
+
config GENERIC_ISA_DMA
bool
diff --git a/arch/v850/Kconfig b/arch/v850/Kconfig
index 04494638b96387..e7fc3e500342ed 100644
--- a/arch/v850/Kconfig
+++ b/arch/v850/Kconfig
@@ -28,6 +28,10 @@ config GENERIC_IRQ_PROBE
bool
default y
+config TIME_LOW_RES
+ bool
+ default y
+
# Turn off some random 386 crap that can affect device config
config ISA
bool
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index 2b6e1757aeddf1..5ae51f1bc7c803 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -418,8 +418,19 @@ hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode)
/* Switch the timer base, if necessary: */
new_base = switch_hrtimer_base(timer, base);
- if (mode == HRTIMER_REL)
+ if (mode == HRTIMER_REL) {
tim = ktime_add(tim, new_base->get_time());
+ /*
+ * CONFIG_TIME_LOW_RES is a temporary way for architectures
+ * to signal that they simply return xtime in
+ * do_gettimeoffset(). In this case we want to round up by
+ * resolution when starting a relative timer, to avoid short
+ * timeouts. This will go away with the GTOD framework.
+ */
+#ifdef CONFIG_TIME_LOW_RES
+ tim = ktime_add(tim, base->resolution);
+#endif
+ }
timer->expires = tim;
enqueue_hrtimer(timer, new_base);
--
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