Re: [Qemu-devel] [for 4.2 PATCH 3/3] timer: last, remove last bits of last

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Pavel Dovgalyuk (dovgaluk@ispras.ru) wrote:
> Hello!
> 
> > From: Dr. David Alan Gilbert (git) [mailto:dgilbert@redhat.com]
> > The reset notifiers kept a 'last' counter to notice jumps;
> > now that we've remove the notifier we don't need to keep 'last'.
> > replay used to save/restore 'last' (presumably to avoid triggering
> > the notifier);  make it store the current time instead which avoids
> > changing it's migration format.
> 
> If you are removing 'last' field, you also should drop 'host_clock_last'
> from ReplayState, because it is used only for restoring host clock
> 'last' field. And that was useful only in record/replay mode.

OK, I'll cook a v2 that removes it and bumps the version.

Dave

> > 
> > Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> > ---
> >  include/qemu/timer.h     | 13 -------------
> >  replay/replay-snapshot.c |  3 +--
> >  util/qemu-timer.c        | 22 +---------------------
> >  3 files changed, 2 insertions(+), 36 deletions(-)
> > 
> > diff --git a/include/qemu/timer.h b/include/qemu/timer.h
> > index 6817c78ef4..5bcab935f6 100644
> > --- a/include/qemu/timer.h
> > +++ b/include/qemu/timer.h
> > @@ -248,19 +248,6 @@ bool qemu_clock_run_timers(QEMUClockType type);
> >   */
> >  bool qemu_clock_run_all_timers(void);
> > 
> > -/**
> > - * qemu_clock_get_last:
> > - *
> > - * Returns last clock query time.
> > - */
> > -uint64_t qemu_clock_get_last(QEMUClockType type);
> > -/**
> > - * qemu_clock_set_last:
> > - *
> > - * Sets last clock query time.
> > - */
> > -void qemu_clock_set_last(QEMUClockType type, uint64_t last);
> > -
> > 
> >  /*
> >   * QEMUTimerList
> > diff --git a/replay/replay-snapshot.c b/replay/replay-snapshot.c
> > index 756f48bc02..ca6d4adcc0 100644
> > --- a/replay/replay-snapshot.c
> > +++ b/replay/replay-snapshot.c
> > @@ -24,7 +24,7 @@ static int replay_pre_save(void *opaque)
> >  {
> >      ReplayState *state = opaque;
> >      state->file_offset = ftell(replay_file);
> > -    state->host_clock_last = qemu_clock_get_last(QEMU_CLOCK_HOST);
> > +    state->host_clock_last = get_clock_realtime();
> > 
> >      return 0;
> >  }
> > @@ -34,7 +34,6 @@ static int replay_post_load(void *opaque, int version_id)
> >      ReplayState *state = opaque;
> >      if (replay_mode == REPLAY_MODE_PLAY) {
> >          fseek(replay_file, state->file_offset, SEEK_SET);
> > -        qemu_clock_set_last(QEMU_CLOCK_HOST, state->host_clock_last);
> >          /* If this was a vmstate, saved in recording mode,
> >             we need to initialize replay data fields. */
> >          replay_fetch_data_kind();
> > diff --git a/util/qemu-timer.c b/util/qemu-timer.c
> > index 2faaaf9926..b73041df4e 100644
> > --- a/util/qemu-timer.c
> > +++ b/util/qemu-timer.c
> > @@ -48,8 +48,6 @@ typedef struct QEMUClock {
> >      /* We rely on BQL to protect the timerlists */
> >      QLIST_HEAD(, QEMUTimerList) timerlists;
> > 
> > -    int64_t last;
> > -
> >      QEMUClockType type;
> >      bool enabled;
> >  } QEMUClock;
> > @@ -130,7 +128,6 @@ static void qemu_clock_init(QEMUClockType type, QEMUTimerListNotifyCB
> > *notify_cb
> > 
> >      clock->type = type;
> >      clock->enabled = (type == QEMU_CLOCK_VIRTUAL ? false : true);
> > -    clock->last = INT64_MIN;
> >      QLIST_INIT(&clock->timerlists);
> >      main_loop_tlg.tl[type] = timerlist_new(type, notify_cb, NULL);
> >  }
> > @@ -628,9 +625,6 @@ int64_t timerlistgroup_deadline_ns(QEMUTimerListGroup *tlg)
> > 
> >  int64_t qemu_clock_get_ns(QEMUClockType type)
> >  {
> > -    int64_t now;
> > -    QEMUClock *clock = qemu_clock_ptr(type);
> > -
> >      switch (type) {
> >      case QEMU_CLOCK_REALTIME:
> >          return get_clock();
> > @@ -642,26 +636,12 @@ int64_t qemu_clock_get_ns(QEMUClockType type)
> >              return cpu_get_clock();
> >          }
> >      case QEMU_CLOCK_HOST:
> > -        now = REPLAY_CLOCK(REPLAY_CLOCK_HOST, get_clock_realtime());
> > -        clock->last = now;
> > -        return now;
> > +        return REPLAY_CLOCK(REPLAY_CLOCK_HOST, get_clock_realtime());
> >      case QEMU_CLOCK_VIRTUAL_RT:
> >          return REPLAY_CLOCK(REPLAY_CLOCK_VIRTUAL_RT, cpu_get_clock());
> >      }
> >  }
> > 
> > -uint64_t qemu_clock_get_last(QEMUClockType type)
> > -{
> > -    QEMUClock *clock = qemu_clock_ptr(type);
> > -    return clock->last;
> > -}
> > -
> > -void qemu_clock_set_last(QEMUClockType type, uint64_t last)
> > -{
> > -    QEMUClock *clock = qemu_clock_ptr(type);
> > -    clock->last = last;
> > -}
> > -
> >  void init_clocks(QEMUTimerListNotifyCB *notify_cb)
> >  {
> >      QEMUClockType type;
> > --
> > 2.21.0
> 
> 
> Pavel Dovgalyuk
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK