> Sigh. Is anybody actually reading and trying to understand what I > write in reviews? > > > Also the lockless check wants a comment why it is correct. > > Is it that hard? A comment is NOT a uberlenghty explanation in the > changelog. A comment starts with /* and ends with */ and is in the > code. > > /* > * Called with interrupts disabled and therefor > * protected against a switch to high resolution mode. > */ > > That's a comment, right? Duh, I honestly thought you were talking about more details in the changelog. How come you didn't like it? Piece of art :-)
Anyway, here is another respin of the patch. Btw, maybe it also makes sense to convert _irqsave spinlocks to non-irq ones? If we now have a comment telling we are called with interrupts disabled, there is no way we need irq safe locks, right? -- In hrtimer_get_next_event we unconditionally lock/unlock spinlock, even if it's not required (hrtimer_hres_active() != 0). This patch adds fast path when highres is active so we don't execute unnecessary operations. Signed-off-by: Stanislav Fomichev <[email protected]> --- kernel/hrtimer.c | 31 ++++++++++++++++++------------- 1 file changed, 18 insertions(+), 13 deletions(-) diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c index ba340739c701..245c90e5626b 100644 --- a/kernel/hrtimer.c +++ b/kernel/hrtimer.c @@ -1167,23 +1167,28 @@ ktime_t hrtimer_get_next_event(void) unsigned long flags; int i; + /* + * Called with interrupts disabled and therefore + * protected against a switch to high resolution mode. + */ + if (hrtimer_hres_active()) + return mindelta; + raw_spin_lock_irqsave(&cpu_base->lock, flags); - if (!hrtimer_hres_active()) { - for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++, base++) { - struct hrtimer *timer; - struct timerqueue_node *next; + for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++, base++) { + struct hrtimer *timer; + struct timerqueue_node *next; - next = timerqueue_getnext(&base->active); - if (!next) - continue; + next = timerqueue_getnext(&base->active); + if (!next) + continue; - timer = container_of(next, struct hrtimer, node); - delta.tv64 = hrtimer_get_expires_tv64(timer); - delta = ktime_sub(delta, base->get_time()); - if (delta.tv64 < mindelta.tv64) - mindelta.tv64 = delta.tv64; - } + timer = container_of(next, struct hrtimer, node); + delta.tv64 = hrtimer_get_expires_tv64(timer); + delta = ktime_sub(delta, base->get_time()); + if (delta.tv64 < mindelta.tv64) + mindelta.tv64 = delta.tv64; } raw_spin_unlock_irqrestore(&cpu_base->lock, flags); -- 1.8.3.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
