Messages in this thread Patch in this message | | | Date | Tue, 27 Apr 2021 10:25:42 +0200 | From | Thomas Gleixner <> | Subject | [patch 5/8] time/timekeeping: Avoid invoking clock_was_set() twice |
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do_adjtimex() might end up scheduling a delayed clock_was_set() via timekeeping_advance() and then invoke clock_was_set() directly which is pointless.
Make timekeeping_advance() return whether an invocation of clock_was_set() is required and handle it at the call sites which allows do_adjtimex() to issue a single direct call if required.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de> --- kernel/time/timekeeping.c | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-)
--- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -2126,7 +2126,7 @@ static u64 logarithmic_accumulation(stru * timekeeping_advance - Updates the timekeeper to the current time and * current NTP tick length */ -static void timekeeping_advance(enum timekeeping_adv_mode mode) +static bool timekeeping_advance(enum timekeeping_adv_mode mode) { struct timekeeper *real_tk = &tk_core.timekeeper; struct timekeeper *tk = &shadow_timekeeper; @@ -2197,9 +2197,8 @@ static void timekeeping_advance(enum tim write_seqcount_end(&tk_core.seq); out: raw_spin_unlock_irqrestore(&timekeeper_lock, flags); - if (clock_set) - /* Have to call _delayed version, since in irq context*/ - clock_was_set_delayed(); + + return !!clock_set; } /** @@ -2208,7 +2207,8 @@ static void timekeeping_advance(enum tim */ void update_wall_time(void) { - timekeeping_advance(TK_ADV_TICK); + if (timekeeping_advance(TK_ADV_TICK)) + clock_was_set_delayed(); } /** @@ -2388,8 +2388,9 @@ int do_adjtimex(struct __kernel_timex *t { struct timekeeper *tk = &tk_core.timekeeper; struct audit_ntp_data ad; - unsigned long flags; + bool clock_set = false; struct timespec64 ts; + unsigned long flags; s32 orig_tai, tai; int ret; @@ -2424,6 +2425,7 @@ int do_adjtimex(struct __kernel_timex *t if (tai != orig_tai) { __timekeeping_set_tai_offset(tk, tai); timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET); + clock_set = true; } tk_update_leap_state(tk); @@ -2434,9 +2436,9 @@ int do_adjtimex(struct __kernel_timex *t /* Update the multiplier immediately if frequency was set directly */ if (txc->modes & (ADJ_FREQUENCY | ADJ_TICK)) - timekeeping_advance(TK_ADV_FREQ); + clock_set |= timekeeping_advance(TK_ADV_FREQ); - if (tai != orig_tai) + if (clock_set) clock_was_set(); ntp_notify_cmos_timer();
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