[PATCH] HZ free ntp

Distangle the NTP update from HZ.  This is necessary for dynamic tick enabled
kernels.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 19 insertions, 11 deletions

diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
index 3afeaa3a73f9..eb12509e00bd 100644
--- a/kernel/time/ntp.c
+++ b/kernel/time/ntp.c
@@ -24,7 +24,7 @@ static u64 tick_length, tick_length_base;
 
 #define MAX_TICKADJ             500             /* microsecs */
 #define MAX_TICKADJ_SCALED      (((u64)(MAX_TICKADJ * NSEC_PER_USEC) << \
-                                  TICK_LENGTH_SHIFT) / HZ)
+                                  TICK_LENGTH_SHIFT) / NTP_INTERVAL_FREQ)
 
 /*
  * phase-lock loop variables
@@ -46,13 +46,17 @@ long time_adjust;
 
 static void ntp_update_frequency(void)
 {
-        tick_length_base = (u64)(tick_usec * NSEC_PER_USEC * USER_HZ) << TICK_LENGTH_SHIFT;
-        tick_length_base += (s64)CLOCK_TICK_ADJUST << TICK_LENGTH_SHIFT;
-        tick_length_base += (s64)time_freq << (TICK_LENGTH_SHIFT - SHIFT_NSEC);
+        u64 second_length = (u64)(tick_usec * NSEC_PER_USEC * USER_HZ)
+                                << TICK_LENGTH_SHIFT;
+        second_length += (s64)CLOCK_TICK_ADJUST << TICK_LENGTH_SHIFT;
+        second_length += (s64)time_freq << (TICK_LENGTH_SHIFT - SHIFT_NSEC);
 
-        do_div(tick_length_base, HZ);
+        tick_length_base = second_length;
 
-        tick_nsec = tick_length_base >> TICK_LENGTH_SHIFT;
+        do_div(second_length, HZ);
+        tick_nsec = second_length >> TICK_LENGTH_SHIFT;
+
+        do_div(tick_length_base, NTP_INTERVAL_FREQ);
 }
 
 /**
@@ -162,7 +166,7 @@ void second_overflow(void)
                         tick_length -= MAX_TICKADJ_SCALED;
                 } else {
                         tick_length += (s64)(time_adjust * NSEC_PER_USEC /
-                                             HZ) << TICK_LENGTH_SHIFT;
+                                        NTP_INTERVAL_FREQ) << TICK_LENGTH_SHIFT;
                         time_adjust = 0;
                 }
         }
@@ -239,7 +243,8 @@ int do_adjtimex(struct timex *txc)
                     result = -EINVAL;
                     goto leave;
                 }
-                time_freq = ((s64)txc->freq * NSEC_PER_USEC) >> (SHIFT_USEC - SHIFT_NSEC);
+                time_freq = ((s64)txc->freq * NSEC_PER_USEC)
+                                >> (SHIFT_USEC - SHIFT_NSEC);
             }
 
             if (txc->modes & ADJ_MAXERROR) {
@@ -309,7 +314,8 @@ int do_adjtimex(struct timex *txc)
                     freq_adj += time_freq;
                     freq_adj = min(freq_adj, (s64)MAXFREQ_NSEC);
                     time_freq = max(freq_adj, (s64)-MAXFREQ_NSEC);
-                    time_offset = (time_offset / HZ) << SHIFT_UPDATE;
+                    time_offset = (time_offset / NTP_INTERVAL_FREQ)
+                                        << SHIFT_UPDATE;
                 } /* STA_PLL */
             } /* txc->modes & ADJ_OFFSET */
             if (txc->modes & ADJ_TICK)
@@ -324,8 +330,10 @@ leave:	if ((time_status & (STA_UNSYNC|STA_CLOCKERR)) != 0)
         if ((txc->modes & ADJ_OFFSET_SINGLESHOT) == ADJ_OFFSET_SINGLESHOT)
             txc->offset    = save_adjust;
         else
-            txc->offset    = shift_right(time_offset, SHIFT_UPDATE) * HZ / 1000;
-        txc->freq          = (time_freq / NSEC_PER_USEC) << (SHIFT_USEC - SHIFT_NSEC);
+            txc->offset    = shift_right(time_offset, SHIFT_UPDATE)
+                                * NTP_INTERVAL_FREQ / 1000;
+        txc->freq          = (time_freq / NSEC_PER_USEC)
+                                << (SHIFT_USEC - SHIFT_NSEC);
         txc->maxerror      = time_maxerror;
         txc->esterror      = time_esterror;
         txc->status        = time_status;