Messages in this thread Patch in this message | | | Date | Mon, 31 Jul 2006 12:36:38 +0200 | From | "Martin Schwidefsky" <> | Subject | Re: [PATCH] simplify update_times (avoid jiffies/jiffies_64 aliasing problem) |
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On 7/30/06, Atsushi Nemoto <anemo@mba.ocn.ne.jp> wrote: > diff --git a/arch/x86_64/kernel/time.c b/arch/x86_64/kernel/time.c > index 7a9b182..298027f 100644 > --- a/arch/x86_64/kernel/time.c > +++ b/arch/x86_64/kernel/time.c > @@ -423,7 +423,8 @@ #endif > > if (lost > 0) { > handle_lost_ticks(lost, regs); > - jiffies += lost; > + while (lost--) > + do_timer(regs); > } > > /*
I think that this is going into the wrong direction. There are a number of architectures that call do_timer(regs) in a while loop. It would be much nicer if do_timer would get the number of passed ticks as an argument. And the "regs" argument to do_timer is just useless.
> diff --git a/kernel/timer.c b/kernel/timer.c > index 05809c2..3981cae 100644 > --- a/kernel/timer.c > +++ b/kernel/timer.c > @@ -1267,12 +1267,9 @@ void run_local_timers(void) > */ > static inline void update_times(void) > { > - unsigned long ticks; > - > - ticks = jiffies - wall_jiffies; > - wall_jiffies += ticks; > + wall_jiffies++; > update_wall_time(); > - calc_load(ticks); > + calc_load(1); > } > > /*
Pass "ticks" from do_timer and do "wall_jiffies += ticks". To make calc_load work correctly the "if (count < 0)" in calc_load needs to be replaced with "while (count < 0)".
> @@ -1284,8 +1281,6 @@ static inline void update_times(void) > void do_timer(struct pt_regs *regs) > { > jiffies_64++; > - /* prevent loading jiffies before storing new jiffies_64 value. */ > - barrier(); > update_times(); > } >
Change do_timer and make architectures to pass "ticks", do "jiffies64 += ticks" and add ticks to the call of update_times.
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