* [PATCH] timekeeping: avoid adjust kernel time once hwclock kept in UTC time @ 2012-12-06 14:03 Dong Zhu 2012-12-19 5:15 ` Dong Zhu 2013-02-22 20:37 ` John Stultz 0 siblings, 2 replies; 5+ messages in thread From: Dong Zhu @ 2012-12-06 14:03 UTC (permalink / raw) To: John Stultz, Thomas Gleixner; +Cc: linux-kernel >From c126376cf1837b0956e0268056db61870fbbc1d4 Mon Sep 17 00:00:00 2001 From: Dong Zhu <bluezhudong@gmail.com> Date: Thu, 6 Dec 2012 21:45:00 +0800 Subject: [PATCH] timekeeping: avoid adjust kernel time once hwclock kept in UTC time If the Hardware Clock kept in local time,kernel will adjust the time to be UTC time.But if Hardware Clock kept in UTC time,system will make a dummy settimeofday call first (sys_tz.tz_minuteswest = 0) to make sure the time is not shifted,so at this point I think maybe it is not necessary to set the kernel time once the sys_tz.tz_minuteswest is zero. Signed-off-by: Dong Zhu <bluezhudong@gmail.com> --- kernel/time.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/kernel/time.c b/kernel/time.c index d226c6a..0b592ce 100644 --- a/kernel/time.c +++ b/kernel/time.c @@ -134,9 +134,11 @@ static inline void warp_clock(void) { struct timespec adjust; - adjust = current_kernel_time(); - adjust.tv_sec += sys_tz.tz_minuteswest * 60; - do_settimeofday(&adjust); + if (sys_tz.tz_minuteswest) { + adjust = current_kernel_time(); + adjust.tv_sec += sys_tz.tz_minuteswest * 60; + do_settimeofday(&adjust); + } } /* -- 1.7.11.7 -- Best Regards, Dong Zhu ^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH] timekeeping: avoid adjust kernel time once hwclock kept in UTC time 2012-12-06 14:03 [PATCH] timekeeping: avoid adjust kernel time once hwclock kept in UTC time Dong Zhu @ 2012-12-19 5:15 ` Dong Zhu 2012-12-19 6:37 ` John Stultz 2013-02-22 20:37 ` John Stultz 1 sibling, 1 reply; 5+ messages in thread From: Dong Zhu @ 2012-12-19 5:15 UTC (permalink / raw) To: John Stultz, Thomas Gleixner; +Cc: linux-kernel On Thu, Dec 06, 2012 at 10:03:34PM +0800, Dong Zhu wrote: > From c126376cf1837b0956e0268056db61870fbbc1d4 Mon Sep 17 00:00:00 2001 > From: Dong Zhu <bluezhudong@gmail.com> > Date: Thu, 6 Dec 2012 21:45:00 +0800 > Subject: [PATCH] timekeeping: avoid adjust kernel time once hwclock kept in > UTC time > > If the Hardware Clock kept in local time,kernel will adjust the time > to be UTC time.But if Hardware Clock kept in UTC time,system will make > a dummy settimeofday call first (sys_tz.tz_minuteswest = 0) to make sure > the time is not shifted,so at this point I think maybe it is not necessary > to set the kernel time once the sys_tz.tz_minuteswest is zero. > > Signed-off-by: Dong Zhu <bluezhudong@gmail.com> > --- > kernel/time.c | 8 +++++--- > 1 file changed, 5 insertions(+), 3 deletions(-) > > diff --git a/kernel/time.c b/kernel/time.c > index d226c6a..0b592ce 100644 > --- a/kernel/time.c > +++ b/kernel/time.c > @@ -134,9 +134,11 @@ static inline void warp_clock(void) > { > struct timespec adjust; > > - adjust = current_kernel_time(); > - adjust.tv_sec += sys_tz.tz_minuteswest * 60; > - do_settimeofday(&adjust); > + if (sys_tz.tz_minuteswest) { > + adjust = current_kernel_time(); > + adjust.tv_sec += sys_tz.tz_minuteswest * 60; > + do_settimeofday(&adjust); > + } > } > > /* > -- > 1.7.11.7 > Hi, Any comments ? -- Best Regards, Dong Zhu ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] timekeeping: avoid adjust kernel time once hwclock kept in UTC time 2012-12-19 5:15 ` Dong Zhu @ 2012-12-19 6:37 ` John Stultz 2013-02-20 8:13 ` Dong Zhu 0 siblings, 1 reply; 5+ messages in thread From: John Stultz @ 2012-12-19 6:37 UTC (permalink / raw) To: Dong Zhu; +Cc: Thomas Gleixner, linux-kernel On 12/18/2012 09:15 PM, Dong Zhu wrote: > On Thu, Dec 06, 2012 at 10:03:34PM +0800, Dong Zhu wrote: >> From c126376cf1837b0956e0268056db61870fbbc1d4 Mon Sep 17 00:00:00 2001 >> From: Dong Zhu <bluezhudong@gmail.com> >> Date: Thu, 6 Dec 2012 21:45:00 +0800 >> Subject: [PATCH] timekeeping: avoid adjust kernel time once hwclock kept in >> UTC time >> >> If the Hardware Clock kept in local time,kernel will adjust the time >> to be UTC time.But if Hardware Clock kept in UTC time,system will make >> a dummy settimeofday call first (sys_tz.tz_minuteswest = 0) to make sure >> the time is not shifted,so at this point I think maybe it is not necessary >> to set the kernel time once the sys_tz.tz_minuteswest is zero. >> >> Signed-off-by: Dong Zhu <bluezhudong@gmail.com> >> --- >> kernel/time.c | 8 +++++--- >> 1 file changed, 5 insertions(+), 3 deletions(-) >> >> diff --git a/kernel/time.c b/kernel/time.c >> index d226c6a..0b592ce 100644 >> --- a/kernel/time.c >> +++ b/kernel/time.c >> @@ -134,9 +134,11 @@ static inline void warp_clock(void) >> { >> struct timespec adjust; >> >> - adjust = current_kernel_time(); >> - adjust.tv_sec += sys_tz.tz_minuteswest * 60; >> - do_settimeofday(&adjust); >> + if (sys_tz.tz_minuteswest) { >> + adjust = current_kernel_time(); >> + adjust.tv_sec += sys_tz.tz_minuteswest * 60; >> + do_settimeofday(&adjust); >> + } >> } >> >> /* >> -- >> 1.7.11.7 >> > Hi, > > Any comments ? Sorry for the slow response, been a little busy. Honestly the warp_clock() code path is always been a bit odd to me, so I've not really been able to get my head around the implications of this change. Really, I'm not sure if I'll get to this before the new year. Its on my list, but don't be afraid to ping me early Jan if I haven't queued it for 3.9 by then. thanks -john ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] timekeeping: avoid adjust kernel time once hwclock kept in UTC time 2012-12-19 6:37 ` John Stultz @ 2013-02-20 8:13 ` Dong Zhu 0 siblings, 0 replies; 5+ messages in thread From: Dong Zhu @ 2013-02-20 8:13 UTC (permalink / raw) To: John Stultz; +Cc: Thomas Gleixner, linux-kernel On Tue, Dec 18, 2012 at 10:37:08PM -0800, John Stultz wrote: > On 12/18/2012 09:15 PM, Dong Zhu wrote: > >On Thu, Dec 06, 2012 at 10:03:34PM +0800, Dong Zhu wrote: > >> From c126376cf1837b0956e0268056db61870fbbc1d4 Mon Sep 17 00:00:00 2001 > >>From: Dong Zhu <bluezhudong@gmail.com> > >>Date: Thu, 6 Dec 2012 21:45:00 +0800 > >>Subject: [PATCH] timekeeping: avoid adjust kernel time once hwclock kept in > >> UTC time > >> > >>If the Hardware Clock kept in local time,kernel will adjust the time > >>to be UTC time.But if Hardware Clock kept in UTC time,system will make > >>a dummy settimeofday call first (sys_tz.tz_minuteswest = 0) to make sure > >>the time is not shifted,so at this point I think maybe it is not necessary > >>to set the kernel time once the sys_tz.tz_minuteswest is zero. > >> > >>Signed-off-by: Dong Zhu <bluezhudong@gmail.com> > >>--- > >> kernel/time.c | 8 +++++--- > >> 1 file changed, 5 insertions(+), 3 deletions(-) > >> > >>diff --git a/kernel/time.c b/kernel/time.c > >>index d226c6a..0b592ce 100644 > >>--- a/kernel/time.c > >>+++ b/kernel/time.c > >>@@ -134,9 +134,11 @@ static inline void warp_clock(void) > >> { > >> struct timespec adjust; > >>- adjust = current_kernel_time(); > >>- adjust.tv_sec += sys_tz.tz_minuteswest * 60; > >>- do_settimeofday(&adjust); > >>+ if (sys_tz.tz_minuteswest) { > >>+ adjust = current_kernel_time(); > >>+ adjust.tv_sec += sys_tz.tz_minuteswest * 60; > >>+ do_settimeofday(&adjust); > >>+ } > >> } > >> /* > >>-- > >>1.7.11.7 > >> > >Hi, > > > >Any comments ? > Sorry for the slow response, been a little busy. Honestly the > warp_clock() code path is always been a bit odd to me, so I've not > really been able to get my head around the implications of this > change. > > Really, I'm not sure if I'll get to this before the new year. > Its on my list, but don't be afraid to ping me early Jan if I > haven't queued it for 3.9 by then. > Hi, Distance my submit over a long time,whether my patch can be applied ? -- Best Regards, Dong Zhu ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] timekeeping: avoid adjust kernel time once hwclock kept in UTC time 2012-12-06 14:03 [PATCH] timekeeping: avoid adjust kernel time once hwclock kept in UTC time Dong Zhu 2012-12-19 5:15 ` Dong Zhu @ 2013-02-22 20:37 ` John Stultz 1 sibling, 0 replies; 5+ messages in thread From: John Stultz @ 2013-02-22 20:37 UTC (permalink / raw) To: Dong Zhu; +Cc: Thomas Gleixner, linux-kernel On 12/06/2012 06:03 AM, Dong Zhu wrote: > From c126376cf1837b0956e0268056db61870fbbc1d4 Mon Sep 17 00:00:00 2001 > From: Dong Zhu <bluezhudong@gmail.com> > Date: Thu, 6 Dec 2012 21:45:00 +0800 > Subject: [PATCH] timekeeping: avoid adjust kernel time once hwclock kept in > UTC time > > If the Hardware Clock kept in local time,kernel will adjust the time > to be UTC time.But if Hardware Clock kept in UTC time,system will make > a dummy settimeofday call first (sys_tz.tz_minuteswest = 0) to make sure > the time is not shifted,so at this point I think maybe it is not necessary > to set the kernel time once the sys_tz.tz_minuteswest is zero. > > Signed-off-by: Dong Zhu <bluezhudong@gmail.com> Sorry for the long delay here, and thank you for the reminder! I've merged this patch in my tree (reworking it to merge with other changes in that area). And I'm likely to make a follow on patch that will use timekeeping_inject_offset() so we don't add any extra time error unnecessarily. Both will be queued for 3.10. thanks -john ^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2013-02-22 20:37 UTC | newest] Thread overview: 5+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2012-12-06 14:03 [PATCH] timekeeping: avoid adjust kernel time once hwclock kept in UTC time Dong Zhu 2012-12-19 5:15 ` Dong Zhu 2012-12-19 6:37 ` John Stultz 2013-02-20 8:13 ` Dong Zhu 2013-02-22 20:37 ` John Stultz
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