diff options
Diffstat (limited to 'kernel/time')
| -rw-r--r-- | kernel/time/timekeeping.c | 31 |
1 files changed, 27 insertions, 4 deletions
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index 21cc23918cbd..34b4cedfa80d 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -1604,9 +1604,12 @@ static __always_inline void timekeeping_freqadjust(struct timekeeper *tk, { s64 interval = tk->cycle_interval; s64 xinterval = tk->xtime_interval; + u32 base = tk->tkr_mono.clock->mult; + u32 max = tk->tkr_mono.clock->maxadj; + u32 cur_adj = tk->tkr_mono.mult; s64 tick_error; bool negative; - u32 adj; + u32 adj_scale; /* Remove any current error adj from freq calculation */ if (tk->ntp_err_mult) @@ -1625,13 +1628,33 @@ static __always_inline void timekeeping_freqadjust(struct timekeeper *tk, /* preserve the direction of correction */ negative = (tick_error < 0); - /* Sort out the magnitude of the correction */ + /* If any adjustment would pass the max, just return */ + if (negative && (cur_adj - 1) <= (base - max)) + return; + if (!negative && (cur_adj + 1) >= (base + max)) + return; + /* + * Sort out the magnitude of the correction, but + * avoid making so large a correction that we go + * over the max adjustment. + */ + adj_scale = 0; tick_error = abs(tick_error); - for (adj = 0; tick_error > interval; adj++) + while (tick_error > interval) { + u32 adj = 1 << (adj_scale + 1); + + /* Check if adjustment gets us within 1 unit from the max */ + if (negative && (cur_adj - adj) <= (base - max)) + break; + if (!negative && (cur_adj + adj) >= (base + max)) + break; + + adj_scale++; tick_error >>= 1; + } /* scale the corrections */ - timekeeping_apply_adjustment(tk, offset, negative, adj); + timekeeping_apply_adjustment(tk, offset, negative, adj_scale); } /* |