lkml.org 
[lkml]   [2013]   [May]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[tip:timers/core] clocksource: Allow clocksource select to skip current clocksource
Commit-ID:  f5a2e34375a5e2b711aea488ac3ae50eeba6d57c
Gitweb: http://git.kernel.org/tip/f5a2e34375a5e2b711aea488ac3ae50eeba6d57c
Author: Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Thu, 25 Apr 2013 20:31:45 +0000
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitDate: Thu, 16 May 2013 11:09:15 +0200

clocksource: Allow clocksource select to skip current clocksource

Preparatory patch for clocksource unbind support.

Split out code from clocksource_select and modify it, so it skips the
current clocksource on request and tries to find a fallback
clocksource. Convert all existing users. No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Magnus Damm <magnus.damm@gmail.com>
Link: http://lkml.kernel.org/r/20130425143435.834965397@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
kernel/time/clocksource.c | 31 ++++++++++++++++++++-----------
1 file changed, 20 insertions(+), 11 deletions(-)

diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index 1923a34..9782997 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -553,7 +553,7 @@ static u64 clocksource_max_deferment(struct clocksource *cs)

#ifndef CONFIG_ARCH_USES_GETTIMEOFFSET

-static struct clocksource *clocksource_find_best(bool oneshot)
+static struct clocksource *clocksource_find_best(bool oneshot, bool skipcur)
{
struct clocksource *cs;

@@ -566,6 +566,8 @@ static struct clocksource *clocksource_find_best(bool oneshot)
* the best rating.
*/
list_for_each_entry(cs, &clocksource_list, list) {
+ if (skipcur && cs == curr_clocksource)
+ continue;
if (oneshot && !(cs->flags & CLOCK_SOURCE_VALID_FOR_HRES))
continue;
return cs;
@@ -573,26 +575,20 @@ static struct clocksource *clocksource_find_best(bool oneshot)
return NULL;
}

-/**
- * clocksource_select - Select the best clocksource available
- *
- * Private function. Must hold clocksource_mutex when called.
- *
- * Select the clocksource with the best rating, or the clocksource,
- * which is selected by userspace override.
- */
-static void clocksource_select(void)
+static void __clocksource_select(bool skipcur)
{
bool oneshot = tick_oneshot_mode_active();
struct clocksource *best, *cs;

/* Find the best suitable clocksource */
- best = clocksource_find_best(oneshot);
+ best = clocksource_find_best(oneshot, skipcur);
if (!best)
return;

/* Check for the override clocksource. */
list_for_each_entry(cs, &clocksource_list, list) {
+ if (skipcur && cs == curr_clocksource)
+ continue;
if (strcmp(cs->name, override_name) != 0)
continue;
/*
@@ -618,6 +614,19 @@ static void clocksource_select(void)
}
}

+/**
+ * clocksource_select - Select the best clocksource available
+ *
+ * Private function. Must hold clocksource_mutex when called.
+ *
+ * Select the clocksource with the best rating, or the clocksource,
+ * which is selected by userspace override.
+ */
+static void clocksource_select(void)
+{
+ return __clocksource_select(false);
+}
+
#else /* !CONFIG_ARCH_USES_GETTIMEOFFSET */

static inline void clocksource_select(void) { }

\
 
 \ /
  Last update: 2013-05-27 12:21    [W:0.243 / U:0.584 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site