Re: [Qemu-devel] [RFC] [PATCHv10 08/31] aio / timers: Split QEMUClock into QEMUClock and QEMUTimerList

[Jan Kiszka <jan.kiszka@siemens.com>]

On 2013-08-11 18:43, Alex Bligh wrote:
> Split QEMUClock into QEMUClock and QEMUTimerList so that we can
> have more than one QEMUTimerList associated with the same clock.
> 
> Introduce a main_loop_timerlist concept and make existing
> qemu_clock_* calls that actually should operate on a QEMUTimerList
> call the relevant QEMUTimerList implementations, using the clock's
> default timerlist. This vastly reduces the invasiveness of this
> change and means the API stays constant for existing users.
> 
> Introduce a list of QEMUTimerLists associated with each clock
> so that reenabling the clock can cause all the notifiers
> to be called. Note the code to do the notifications is added
> in a later patch.
> 
> Switch QEMUClockType to an enum. Remove global variables vm_clock,
> host_clock and rt_clock and add compatibility defines. Do not
> fix qemu_next_alarm_deadline as it's going to be deleted.
> 
> Add qemu_clock_use_for_deadline to indicate whether a particular
> clock should be used for deadline calculations. When use_icount
> is true, vm_clock should not be used for deadline calculations
> as it does not contain a nanosecond count. Instead, icount
> timeouts come from the execution thread doing aio_notify or
> qemu_notify as appropriate. This function is used in the next
> patch.
> 
> Signed-off-by: Alex Bligh <alex@alex.org.uk>
> ---
>  include/qemu/timer.h |  347 ++++++++++++++++++++++++++++++++++++++++++++++----
>  qemu-timer.c         |  207 ++++++++++++++++++++++--------
>  2 files changed, 475 insertions(+), 79 deletions(-)
> 
> diff --git a/include/qemu/timer.h b/include/qemu/timer.h
> index fcb6a42..a217a81 100644
> --- a/include/qemu/timer.h
> +++ b/include/qemu/timer.h
> @@ -11,34 +11,84 @@
>  #define SCALE_US 1000
>  #define SCALE_NS 1
>  
> -#define QEMU_CLOCK_REALTIME 0
> -#define QEMU_CLOCK_VIRTUAL  1
> -#define QEMU_CLOCK_HOST     2
> +/**
> + * QEMUClockType:
> + *
> + * The following clock types are available:
> + *
> + * @QEMU_CLOCK_REALTIME: Real time clock
> + *
> + * The real time clock should be used only for stuff which does not
> + * change the virtual machine state, as it is run even if the virtual
> + * machine is stopped. The real time clock has a frequency of 1000
> + * Hz.
> + *
> + * Formerly rt_clock
> + *
> + * @QEMU_CLOCK_VIRTUAL: virtual clock
> + *
> + * The virtual clock is only run during the emulation. It is stopped
> + * when the virtual machine is stopped. Virtual timers use a high
> + * precision clock, usually cpu cycles (use ticks_per_sec).
> + *
> + * Formerly vm_clock
> + *
> + * @QEMU_CLOCK_HOST: host clock
> + *
> + * The host clock should be use for device models that emulate accurate
> + * real time sources. It will continue to run when the virtual machine
> + * is suspended, and it will reflect system time changes the host may
> + * undergo (e.g. due to NTP). The host clock has the same precision as
> + * the virtual clock.
> + *
> + * Formerly host_clock
> + */
> +
> +typedef enum {
> +    QEMU_CLOCK_REALTIME = 0,
> +    QEMU_CLOCK_VIRTUAL = 1,
> +    QEMU_CLOCK_HOST = 2,
> +    QEMU_CLOCK_MAX
> +} QEMUClockType;
>  
>  typedef struct QEMUClock QEMUClock;
> +typedef struct QEMUTimerList QEMUTimerList;
>  typedef void QEMUTimerCB(void *opaque);
>  
> -/* The real time clock should be used only for stuff which does not
> -   change the virtual machine state, as it is run even if the virtual
> -   machine is stopped. The real time clock has a frequency of 1000
> -   Hz. */
> -extern QEMUClock *rt_clock;
> +typedef struct QEMUTimer {
> +    int64_t expire_time;        /* in nanoseconds */
> +    QEMUTimerList *timer_list;
> +    QEMUTimerCB *cb;
> +    void *opaque;
> +    QEMUTimer *next;
> +    int scale;
> +} QEMUTimer;

The typedef part is a duplication of what we already have in
qemu/typedefs.h and breaks the build for me. Just declare the struct here.

Jan

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