| Message ID | 20241009-devel-anna-maria-b4-timers-ptp-timekeeping-v2-18-554456a44a15@linutronix.de (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
| Series | timekeeping: Rework to prepare support of indenpendent PTP clocks | expand |
| Context | Check | Description |
|---|---|---|
| netdev/tree_selection | success | Not a local patch |
On Wed, Oct 9, 2024 at 1:29 AM Anna-Maria Behnsen <anna-maria@linutronix.de> wrote: > > From: Anna-Maria Behnsen <anna-maria@linutronix.de> > > Updates of the timekeeper can be done by operating on the shadow timekeeper > and afterwards copying the result into the real timekeeper. This has the > advantage, that the sequence count write protected region is kept as small > as possible. > > Convert change_clocksource() to use this scheme. > > Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de> > --- > kernel/time/timekeeping.c | 18 +++++++----------- > 1 file changed, 7 insertions(+), 11 deletions(-) > > diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c > index 051041e92e54..6d21e9bf5c35 100644 > --- a/kernel/time/timekeeping.c > +++ b/kernel/time/timekeeping.c > @@ -1596,9 +1596,7 @@ static void __timekeeping_set_tai_offset(struct timekeeper *tk, s32 tai_offset) > */ > static int change_clocksource(void *data) > { > - struct timekeeper *tk = &tk_core.timekeeper; > struct clocksource *new = data, *old = NULL; > - unsigned long flags; > > /* > * If the clocksource is in a module, get a module reference. > @@ -1614,16 +1612,14 @@ static int change_clocksource(void *data) > return 0; > } > > - raw_spin_lock_irqsave(&tk_core.lock, flags); > - write_seqcount_begin(&tk_core.seq); > - > - timekeeping_forward_now(tk); > - old = tk->tkr_mono.clock; > - tk_setup_internals(tk, new); > - timekeeping_update(&tk_core, tk, TK_UPDATE_ALL | TK_MIRROR); > + scoped_guard (raw_spinlock_irqsave, &tk_core.lock) { > + struct timekeeper *tk = &tk_core.shadow_timekeeper; Same nit: tk_shadow maybe? Acked-by: John Stultz <jstultz@google.com>
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index 051041e92e54..6d21e9bf5c35 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -1596,9 +1596,7 @@ static void __timekeeping_set_tai_offset(struct timekeeper *tk, s32 tai_offset) */ static int change_clocksource(void *data) { - struct timekeeper *tk = &tk_core.timekeeper; struct clocksource *new = data, *old = NULL; - unsigned long flags; /* * If the clocksource is in a module, get a module reference. @@ -1614,16 +1612,14 @@ static int change_clocksource(void *data) return 0; } - raw_spin_lock_irqsave(&tk_core.lock, flags); - write_seqcount_begin(&tk_core.seq); - - timekeeping_forward_now(tk); - old = tk->tkr_mono.clock; - tk_setup_internals(tk, new); - timekeeping_update(&tk_core, tk, TK_UPDATE_ALL | TK_MIRROR); + scoped_guard (raw_spinlock_irqsave, &tk_core.lock) { + struct timekeeper *tk = &tk_core.shadow_timekeeper; - write_seqcount_end(&tk_core.seq); - raw_spin_unlock_irqrestore(&tk_core.lock, flags); + timekeeping_forward_now(tk); + old = tk->tkr_mono.clock; + tk_setup_internals(tk, new); + timekeeping_update_staged(&tk_core, TK_UPDATE_ALL); + } if (old) { if (old->disable)