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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2009-06-15 20:58:33 +0400 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-06-15 20:58:33 +0400 |
| commit | 3f27c0d2a469673e0f1efc8004b6f42428aa5b94 (patch) | |
| tree | 548c975cabdcafcac92992d24410ae0a8334dff5 /kernel | |
| parent | 9aaa630503f20461bee65ebc4fd87ba8d7a2bd2c (diff) | |
| parent | cd6d95d8449b7c9f415f26041e9ae173d387b6bd (diff) | |
| download | linux-3f27c0d2a469673e0f1efc8004b6f42428aa5b94.tar.xz | |
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
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/time/clocksource.c | 20 | ||||
| -rw-r--r-- | kernel/time/tick-oneshot.c | 17 |
2 files changed, 36 insertions, 1 deletions
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, } } + /* + * Check to make sure we don't switch to a non-highres capable + * clocksource if the tick code is in oneshot mode (highres or nohz) + */ + if (tick_oneshot_mode_active() && + !(ovr->flags & CLOCK_SOURCE_VALID_FOR_HRES)) { + printk(KERN_WARNING "%s clocksource is not HRT compatible. " + "Cannot switch while in HRT/NOHZ mode\n", ovr->name); + ovr = NULL; + override_name[0] = 0; + } + /* Reselect, when the override name has changed */ if (ovr != clocksource_override) { clocksource_override = ovr; @@ -537,7 +549,13 @@ sysfs_show_available_clocksources(struct sys_device *dev, spin_lock_irq(&clocksource_lock); list_for_each_entry(src, &clocksource_list, list) { - count += snprintf(buf + count, + /* + * Don't show non-HRES clocksource if the tick code is + * in one shot mode (highres=on or nohz=on) + */ + if (!tick_oneshot_mode_active() || + (src->flags & CLOCK_SOURCE_VALID_FOR_HRES)) + count += snprintf(buf + count, max((ssize_t)PAGE_SIZE - count, (ssize_t)0), "%s ", src->name); } 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 *)) return 0; } +/** + * tick_check_oneshot_mode - check whether the system is in oneshot mode + * + * returns 1 when either nohz or highres are enabled. otherwise 0. + */ +int tick_oneshot_mode_active(void) +{ + unsigned long flags; + int ret; + + local_irq_save(flags); + ret = __get_cpu_var(tick_cpu_device).mode == TICKDEV_MODE_ONESHOT; + local_irq_restore(flags); + + return ret; +} + #ifdef CONFIG_HIGH_RES_TIMERS /** * tick_init_highres - switch to high resolution mode |