Messages in this thread |  | | Subject | Re: [PATCH v8 2/6] time: sync read_boot_clock64() with persistent clock | From | Dou Liyang <> | Date | Mon, 13 Nov 2017 11:47:41 +0800 |
| |
Hi Pavel,
At 11/09/2017 11:01 AM, Pavel Tatashin wrote: > read_boot_clock64() returns a boot start timestamp from epoch. Some arches > may need to access the persistent clock interface in order to calculate the > epoch offset. The resolution of the persistent clock, however, might be > low. Therefore, in order to avoid time discrepancies a new argument 'now' > is added to read_boot_clock64() parameters. Arch may decide to use it > instead of accessing persistent clock again. > > Also, change read_boot_clock64() to have __init prototype since it is > accessed only during boot. > > Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com> > --- > arch/arm/kernel/time.c | 2 +- > arch/s390/kernel/time.c | 2 +- > include/linux/timekeeping.h | 7 +++---- > kernel/time/timekeeping.c | 8 ++++++-- > 4 files changed, 11 insertions(+), 8 deletions(-) > > diff --git a/arch/arm/kernel/time.c b/arch/arm/kernel/time.c > index 629f8e9981f1..5b259261a268 100644 > --- a/arch/arm/kernel/time.c > +++ b/arch/arm/kernel/time.c > @@ -90,7 +90,7 @@ void read_persistent_clock64(struct timespec64 *ts) > __read_persistent_clock(ts); > } > > -void read_boot_clock64(struct timespec64 *ts) > +void __init read_boot_clock64(struct timespec64 *now, struct timespec64 *ts) > { > __read_boot_clock(ts); > } > diff --git a/arch/s390/kernel/time.c b/arch/s390/kernel/time.c > index 5cbd52169348..780b770e6a89 100644 > --- a/arch/s390/kernel/time.c > +++ b/arch/s390/kernel/time.c > @@ -220,7 +220,7 @@ void read_persistent_clock64(struct timespec64 *ts) > ext_to_timespec64(clk, ts); > } > > -void read_boot_clock64(struct timespec64 *ts) > +void __init read_boot_clock64(struct timespec64 *now, struct timespec64 *ts) > { > unsigned char clk[STORE_CLOCK_EXT_SIZE]; > __u64 delta; > diff --git a/include/linux/timekeeping.h b/include/linux/timekeeping.h > index c198ab40c04f..73919982045e 100644 > --- a/include/linux/timekeeping.h > +++ b/include/linux/timekeeping.h > @@ -211,9 +211,8 @@ extern void ktime_get_snapshot(struct system_time_snapshot *systime_snapshot); > */ > extern int persistent_clock_is_local; > > -extern void read_persistent_clock64(struct timespec64 *ts); > -extern void read_boot_clock64(struct timespec64 *ts); > -extern int update_persistent_clock64(struct timespec64 now); > - > +void read_persistent_clock64(struct timespec64 *ts); > +void read_boot_clock64(struct timespec64 *now, struct timespec64 *ts); > +int update_persistent_clock64(struct timespec64 now); >
why we should remove the *extern* keyword?
Thanks, dou.
|  |