From: Thomas Gleixner <tglx@linutronix.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
Anna-Maria Behnsen <anna-maria@linutronix.de>,
Marcelo Tosatti <mtosatti@redhat.com>,
Frederic Weisbecker <frederic@kernel.org>
Subject: [patch V2 07/10] time/timekeeping: Avoid invoking clock_was_set() twice
Date: Tue, 13 Jul 2021 15:39:52 +0200 [thread overview]
Message-ID: <20210713135158.580966888@linutronix.de> (raw)
In-Reply-To: 20210713133945.063650594@linutronix.de
From: Thomas Gleixner <tglx@linutronix.de>
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
@@ -2127,7 +2127,7 @@ 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;
@@ -2198,9 +2198,8 @@ 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;
}
/**
@@ -2209,7 +2208,8 @@ 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();
}
/**
@@ -2389,8 +2389,9 @@ 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;
@@ -2425,6 +2426,7 @@ 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);
@@ -2435,9 +2437,9 @@ 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();
next prev parent reply other threads:[~2021-07-13 13:54 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-13 13:39 [patch V2 00/10] hrtimer: Reprogramming and clock_was_set() overhaul Thomas Gleixner
2021-07-13 13:39 ` [patch V2 01/10] hrtimer: Avoid double reprogramming in __hrtimer_start_range_ns() Thomas Gleixner
2021-08-10 16:02 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2021-07-13 13:39 ` [patch V2 02/10] hrtimer: Consolidate reprogramming code Thomas Gleixner
2021-08-10 16:02 ` [tip: timers/core] " tip-bot2 for Peter Zijlstra
2021-08-12 7:19 ` Mike Galbraith
2021-08-12 14:11 ` Thomas Gleixner
2021-08-12 14:32 ` Thomas Gleixner
2021-08-12 15:04 ` Mike Galbraith
2021-08-12 15:22 ` Thomas Gleixner
2021-08-12 15:31 ` Mike Galbraith
2021-08-12 16:58 ` Thomas Gleixner
2021-08-12 15:27 ` Mike Galbraith
2021-08-12 20:32 ` [PATCH] hrtimer: Unbreak hrtimer_force_reprogram() Thomas Gleixner
2021-08-12 20:40 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2021-08-13 7:58 ` [PATCH] " Thomas Gleixner
2021-08-12 20:31 ` [PATCH] hrtimer: Use raw_cpu_ptr() in clock_was_set() Thomas Gleixner
2021-08-12 20:40 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2021-08-13 6:42 ` [PATCH] " Marek Szyprowski
[not found] ` <CGME20210812130945eucas1p117fc1e90f31c8d9fd177932cd1a18512@eucas1p1.samsung.com>
2021-08-12 13:09 ` [patch V2 02/10] hrtimer: Consolidate reprogramming code Marek Szyprowski
2021-07-13 13:39 ` [patch V2 03/10] hrtimer: Ensure timerfd notification for HIGHRES=n Thomas Gleixner
2021-08-10 16:02 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2021-07-13 13:39 ` [patch V2 04/10] hrtimer: Force clock_was_set() handling for the HIGHRES=n, NOHZ=y case Thomas Gleixner
2021-08-10 16:02 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2021-07-13 13:39 ` [patch V2 05/10] timerfd: Provide timerfd_resume() Thomas Gleixner
2021-08-10 16:02 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2021-07-13 13:39 ` [patch V2 06/10] timekeeping: Distangle resume and clock-was-set events Thomas Gleixner
2021-08-10 16:02 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2021-07-13 13:39 ` Thomas Gleixner [this message]
2021-08-10 16:02 ` [tip: timers/core] time/timekeeping: Avoid invoking clock_was_set() twice tip-bot2 for Thomas Gleixner
2021-07-13 13:39 ` [patch V2 08/10] hrtimer: Add bases argument to clock_was_set() Thomas Gleixner
2021-08-10 16:02 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2021-07-13 13:39 ` [patch V2 09/10] hrtimer: Avoid unnecessary SMP function calls in clock_was_set() Thomas Gleixner
2021-08-10 16:02 ` [tip: timers/core] " tip-bot2 for Marcelo Tosatti
2021-07-13 13:39 ` [patch V2 10/10] hrtimer: Avoid more " Thomas Gleixner
2021-08-10 16:02 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
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