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author | Linus Torvalds <torvalds@linux-foundation.org> | 2009-06-15 12:58:33 -0400 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-06-15 12:58:33 -0400 |
commit | 3f27c0d2a469673e0f1efc8004b6f42428aa5b94 (patch) | |
tree | 548c975cabdcafcac92992d24410ae0a8334dff5 | |
parent | 9aaa630503f20461bee65ebc4fd87ba8d7a2bd2c (diff) | |
parent | cd6d95d8449b7c9f415f26041e9ae173d387b6bd (diff) |
Merge branch 'timers-for-linus-clocksource' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'timers-for-linus-clocksource' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
clocksource: prevent selection of low resolution clocksourse also for nohz=on
clocksource: sanity check sysfs clocksource changes
-rw-r--r-- | include/linux/tick.h | 3 | ||||
-rw-r--r-- | kernel/time/clocksource.c | 20 | ||||
-rw-r--r-- | kernel/time/tick-oneshot.c | 17 |
3 files changed, 39 insertions, 1 deletions
diff --git a/include/linux/tick.h b/include/linux/tick.h index 469b82d88b3b..0482229c07db 100644 --- a/include/linux/tick.h +++ b/include/linux/tick.h | |||
@@ -97,10 +97,12 @@ extern void tick_clock_notify(void); | |||
97 | extern int tick_check_oneshot_change(int allow_nohz); | 97 | extern int tick_check_oneshot_change(int allow_nohz); |
98 | extern struct tick_sched *tick_get_tick_sched(int cpu); | 98 | extern struct tick_sched *tick_get_tick_sched(int cpu); |
99 | extern void tick_check_idle(int cpu); | 99 | extern void tick_check_idle(int cpu); |
100 | extern int tick_oneshot_mode_active(void); | ||
100 | # else | 101 | # else |
101 | static inline void tick_clock_notify(void) { } | 102 | static inline void tick_clock_notify(void) { } |
102 | static inline int tick_check_oneshot_change(int allow_nohz) { return 0; } | 103 | static inline int tick_check_oneshot_change(int allow_nohz) { return 0; } |
103 | static inline void tick_check_idle(int cpu) { } | 104 | static inline void tick_check_idle(int cpu) { } |
105 | static inline int tick_oneshot_mode_active(void) { return 0; } | ||
104 | # endif | 106 | # endif |
105 | 107 | ||
106 | #else /* CONFIG_GENERIC_CLOCKEVENTS */ | 108 | #else /* CONFIG_GENERIC_CLOCKEVENTS */ |
@@ -109,6 +111,7 @@ static inline void tick_cancel_sched_timer(int cpu) { } | |||
109 | static inline void tick_clock_notify(void) { } | 111 | static inline void tick_clock_notify(void) { } |
110 | static inline int tick_check_oneshot_change(int allow_nohz) { return 0; } | 112 | static inline int tick_check_oneshot_change(int allow_nohz) { return 0; } |
111 | static inline void tick_check_idle(int cpu) { } | 113 | static inline void tick_check_idle(int cpu) { } |
114 | static inline int tick_oneshot_mode_active(void) { return 0; } | ||
112 | #endif /* !CONFIG_GENERIC_CLOCKEVENTS */ | 115 | #endif /* !CONFIG_GENERIC_CLOCKEVENTS */ |
113 | 116 | ||
114 | # ifdef CONFIG_NO_HZ | 117 | # ifdef CONFIG_NO_HZ |
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c index 80189f6f1c5a..592bf584d1d2 100644 --- a/kernel/time/clocksource.c +++ b/kernel/time/clocksource.c | |||
@@ -509,6 +509,18 @@ static ssize_t sysfs_override_clocksource(struct sys_device *dev, | |||
509 | } | 509 | } |
510 | } | 510 | } |
511 | 511 | ||
512 | /* | ||
513 | * Check to make sure we don't switch to a non-highres capable | ||
514 | * clocksource if the tick code is in oneshot mode (highres or nohz) | ||
515 | */ | ||
516 | if (tick_oneshot_mode_active() && | ||
517 | !(ovr->flags & CLOCK_SOURCE_VALID_FOR_HRES)) { | ||
518 | printk(KERN_WARNING "%s clocksource is not HRT compatible. " | ||
519 | "Cannot switch while in HRT/NOHZ mode\n", ovr->name); | ||
520 | ovr = NULL; | ||
521 | override_name[0] = 0; | ||
522 | } | ||
523 | |||
512 | /* Reselect, when the override name has changed */ | 524 | /* Reselect, when the override name has changed */ |
513 | if (ovr != clocksource_override) { | 525 | if (ovr != clocksource_override) { |
514 | clocksource_override = ovr; | 526 | clocksource_override = ovr; |
@@ -537,7 +549,13 @@ sysfs_show_available_clocksources(struct sys_device *dev, | |||
537 | 549 | ||
538 | spin_lock_irq(&clocksource_lock); | 550 | spin_lock_irq(&clocksource_lock); |
539 | list_for_each_entry(src, &clocksource_list, list) { | 551 | list_for_each_entry(src, &clocksource_list, list) { |
540 | count += snprintf(buf + count, | 552 | /* |
553 | * Don't show non-HRES clocksource if the tick code is | ||
554 | * in one shot mode (highres=on or nohz=on) | ||
555 | */ | ||
556 | if (!tick_oneshot_mode_active() || | ||
557 | (src->flags & CLOCK_SOURCE_VALID_FOR_HRES)) | ||
558 | count += snprintf(buf + count, | ||
541 | max((ssize_t)PAGE_SIZE - count, (ssize_t)0), | 559 | max((ssize_t)PAGE_SIZE - count, (ssize_t)0), |
542 | "%s ", src->name); | 560 | "%s ", src->name); |
543 | } | 561 | } |
diff --git a/kernel/time/tick-oneshot.c b/kernel/time/tick-oneshot.c index 2e8de678e767..a96c0e2b89cf 100644 --- a/kernel/time/tick-oneshot.c +++ b/kernel/time/tick-oneshot.c | |||
@@ -128,6 +128,23 @@ int tick_switch_to_oneshot(void (*handler)(struct clock_event_device *)) | |||
128 | return 0; | 128 | return 0; |
129 | } | 129 | } |
130 | 130 | ||
131 | /** | ||
132 | * tick_check_oneshot_mode - check whether the system is in oneshot mode | ||
133 | * | ||
134 | * returns 1 when either nohz or highres are enabled. otherwise 0. | ||
135 | */ | ||
136 | int tick_oneshot_mode_active(void) | ||
137 | { | ||
138 | unsigned long flags; | ||
139 | int ret; | ||
140 | |||
141 | local_irq_save(flags); | ||
142 | ret = __get_cpu_var(tick_cpu_device).mode == TICKDEV_MODE_ONESHOT; | ||
143 | local_irq_restore(flags); | ||
144 | |||
145 | return ret; | ||
146 | } | ||
147 | |||
131 | #ifdef CONFIG_HIGH_RES_TIMERS | 148 | #ifdef CONFIG_HIGH_RES_TIMERS |
132 | /** | 149 | /** |
133 | * tick_init_highres - switch to high resolution mode | 150 | * tick_init_highres - switch to high resolution mode |