diff options
| author | Pekka Enberg <penberg@kernel.org> | 2010-10-24 19:57:05 +0300 |
|---|---|---|
| committer | Pekka Enberg <penberg@kernel.org> | 2010-10-24 19:57:05 +0300 |
| commit | 6d4121f6c20a0e86231d52f535f1c82423b3326f (patch) | |
| tree | 5c235cac699ca86b504850aa663ddadde0455a61 /kernel/time/ntp.c | |
| parent | 92a5bbc11ff2442a54b2f1d313088c245828ef4e (diff) | |
| parent | 35da7a307c535f9c2929cae277f3df425c9f9b1e (diff) | |
Merge branch 'master' into for-linus
Conflicts:
include/linux/percpu.h
mm/percpu.c
Diffstat (limited to 'kernel/time/ntp.c')
| -rw-r--r-- | kernel/time/ntp.c | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c index c63116863a8..d2321891538 100644 --- a/kernel/time/ntp.c +++ b/kernel/time/ntp.c @@ -149,10 +149,18 @@ static void ntp_update_offset(long offset) time_reftime = get_seconds(); offset64 = offset; - freq_adj = (offset64 * secs) << - (NTP_SCALE_SHIFT - 2 * (SHIFT_PLL + 2 + time_constant)); + freq_adj = ntp_update_offset_fll(offset64, secs); - freq_adj += ntp_update_offset_fll(offset64, secs); + /* + * Clamp update interval to reduce PLL gain with low + * sampling rate (e.g. intermittent network connection) + * to avoid instability. + */ + if (unlikely(secs > 1 << (SHIFT_PLL + 1 + time_constant))) + secs = 1 << (SHIFT_PLL + 1 + time_constant); + + freq_adj += (offset64 * secs) << + (NTP_SCALE_SHIFT - 2 * (SHIFT_PLL + 2 + time_constant)); freq_adj = min(freq_adj + time_freq, MAXFREQ_SCALED); |