system/linux
system/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux synced 2024-09-06 18:01:05 +00:00
Code Issues Packages Projects Releases Wiki Activity

time/timekeeping: Avoid invoking clock_was_set() twice

Browse source 
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>
Link: https://lore.kernel.org/r/20210713135158.580966888@linutronix.de
This commit is contained in:
Thomas Gleixner 2021-07-13 15:39:52 +02:00
parent a761a67f59
commit 1b267793f4
1 changed files with 10 additions and 8 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

18
kernel/time/timekeeping.c
View file

@ -2127,7 +2127,7 @@ static u64 logarithmic_accumulation(struct timekeeper *tk, u64 offset,
* 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 timekeeping_adv_mode mode)
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 timekeeping_adv_mode mode)
*/
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 *txc)
{
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 *txc)
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 *txc)
/* 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();