Messages in this thread Patch in this message | | | Date | Thu, 26 Sep 2019 22:18:25 +0200 | From | Ingo Molnar <> | Subject | [GIT PULL] timer fix |
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Linus,
Please pull the latest timers-urgent-for-linus git tree from:
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git timers-urgent-for-linus
# HEAD: e430d802d6a3aaf61bd3ed03d9404888a29b9bf9 timer: Read jiffies once when forwarding base clk
Fixes a timer expiry bug that would cause spurious delay of timers.
Thanks,
Ingo
------------------> Li RongQing (1): timer: Read jiffies once when forwarding base clk
kernel/time/timer.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/kernel/time/timer.c b/kernel/time/timer.c index 0e315a2e77ae..4820823515e9 100644 --- a/kernel/time/timer.c +++ b/kernel/time/timer.c @@ -1678,24 +1678,26 @@ void timer_clear_idle(void) static int collect_expired_timers(struct timer_base *base, struct hlist_head *heads) { + unsigned long now = READ_ONCE(jiffies); + /* * NOHZ optimization. After a long idle sleep we need to forward the * base to current jiffies. Avoid a loop by searching the bitfield for * the next expiring timer. */ - if ((long)(jiffies - base->clk) > 2) { + if ((long)(now - base->clk) > 2) { unsigned long next = __next_timer_interrupt(base); /* * If the next timer is ahead of time forward to current * jiffies, otherwise forward to the next expiry time: */ - if (time_after(next, jiffies)) { + if (time_after(next, now)) { /* * The call site will increment base->clk and then * terminate the expiry loop immediately. */ - base->clk = jiffies; + base->clk = now; return 0; } base->clk = next;
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