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Message-ID: <3441609.rVjWXosy3s@aspire.rjw.lan> Date: Sun, 08 Apr 2018 10:20:30 +0200 From: "Rafael J. Wysocki" <rjw@...ysocki.net> To: Frederic Weisbecker <frederic@...nel.org> Cc: Linux PM <linux-pm@...r.kernel.org>, Peter Zijlstra <peterz@...radead.org>, Frederic Weisbecker <fweisbec@...il.com>, Thomas Gleixner <tglx@...utronix.de>, Paul McKenney <paulmck@...ux.vnet.ibm.com>, Thomas Ilsche <thomas.ilsche@...dresden.de>, Doug Smythies <dsmythies@...us.net>, Rik van Riel <riel@...riel.com>, Aubrey Li <aubrey.li@...ux.intel.com>, Mike Galbraith <mgalbraith@...e.de>, LKML <linux-kernel@...r.kernel.org>, Len Brown <len.brown@...el.com> Subject: Re: [PATCH v9 07/10] time: hrtimer: Introduce hrtimer_next_event_without() On Saturday, April 7, 2018 4:46:38 PM CEST Frederic Weisbecker wrote: > On Wed, Apr 04, 2018 at 10:45:39AM +0200, Rafael J. Wysocki wrote: > > From: Rafael J. Wysocki <rafael.j.wysocki@...el.com> > > > > The next set of changes will need to compute the time to the next > > hrtimer event over all hrtimers except for the scheduler tick one. > > > > To that end introduce a new helper function, > > hrtimer_next_event_without(), for computing the time until the next > > hrtimer event over all timers except for one and modify the underlying > > code in __hrtimer_next_event_base() to prepare it for being called by > > that new function. > > > > No intentional changes in functionality. > > > > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com> > > --- > > > > v8 -> v9: > > * Make fewer changes to the existing code. > > * Add a new helper function for the handling of the use case at hand. > > > > --- > > include/linux/hrtimer.h | 1 > > kernel/time/hrtimer.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++-- > > 2 files changed, 54 insertions(+), 2 deletions(-) > > > > Index: linux-pm/include/linux/hrtimer.h > > =================================================================== > > --- linux-pm.orig/include/linux/hrtimer.h > > +++ linux-pm/include/linux/hrtimer.h > > @@ -426,6 +426,7 @@ static inline ktime_t hrtimer_get_remain > > } > > > > extern u64 hrtimer_get_next_event(void); > > +extern u64 hrtimer_next_event_without(const struct hrtimer *exclude); > > > > extern bool hrtimer_active(const struct hrtimer *timer); > > > > Index: linux-pm/kernel/time/hrtimer.c > > =================================================================== > > --- linux-pm.orig/kernel/time/hrtimer.c > > +++ linux-pm/kernel/time/hrtimer.c > > @@ -490,6 +490,7 @@ __next_base(struct hrtimer_cpu_base *cpu > > while ((base = __next_base((cpu_base), &(active)))) > > > > static ktime_t __hrtimer_next_event_base(struct hrtimer_cpu_base *cpu_base, > > + const struct hrtimer *exclude, > > unsigned int active, > > ktime_t expires_next) > > { > > @@ -502,9 +503,24 @@ static ktime_t __hrtimer_next_event_base > > > > next = timerqueue_getnext(&base->active); > > timer = container_of(next, struct hrtimer, node); > > + if (timer == exclude) { > > + /* Get to the next timer in the queue. */ > > + struct rb_node *rbn = rb_next(&next->node); > > + > > + next = rb_entry_safe(rbn, struct timerqueue_node, node); > > + if (!next) > > + continue; > > Minor cosmectic detail again, timerqueue_iterate_next() would do the job and > avoid browsing timerqueue details. And below is a patch to make this change on top of the original. --- From: Rafael J. Wysocki <rafael.j.wysocki@...el.com> Subject: [PATCH] time: hrtimer: Use timerqueue_iterate_next() to get to the next timer Use timerqueue_iterate_next() to get to the next timer in __hrtimer_next_event_base() without browsing the timerqueue details diredctly. No intentional changes in functionality. Suggested-by: Frederic Weisbecker <frederic@...nel.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com> --- kernel/time/hrtimer.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) Index: linux-pm/kernel/time/hrtimer.c =================================================================== --- linux-pm.orig/kernel/time/hrtimer.c +++ linux-pm/kernel/time/hrtimer.c @@ -505,9 +505,7 @@ static ktime_t __hrtimer_next_event_base timer = container_of(next, struct hrtimer, node); if (timer == exclude) { /* Get to the next timer in the queue. */ - struct rb_node *rbn = rb_next(&next->node); - - next = rb_entry_safe(rbn, struct timerqueue_node, node); + next = timerqueue_iterate_next(next); if (!next) continue;
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