Re: [PATCH 4/5] x86/time: refactor read_platform_stime()

[Andrew Cooper <andrew.cooper3@citrix.com>]

On 17/03/16 16:12, Joao Martins wrote:
> To fetch the last read from the clocksource which was used to
> calculate system_time. In the case of clocksource=tsc we will
> use it to set tsc_timestamp.
>
> Signed-off-by: Joao Martins <joao.m.martins@oracle.com>

Again, just minor style issues.

Reviewed-by Andrew Cooper <andrew.cooper3@citrix.com>

> ---
> Cc: Keir Fraser <keir@xen.org>
> Cc: Jan Beulich <jbeulich@suse.com>
> Cc: Andrew Cooper <andrew.cooper3@citrix.com>
> ---
>  xen/arch/x86/time.c | 16 ++++++++++------
>  1 file changed, 10 insertions(+), 6 deletions(-)
>
> diff --git a/xen/arch/x86/time.c b/xen/arch/x86/time.c
> index 5af8902..89c35d0 100644
> --- a/xen/arch/x86/time.c
> +++ b/xen/arch/x86/time.c
> @@ -508,6 +508,7 @@ static s_time_t stime_platform_stamp; /* System time at below platform time */
>  static u64 platform_timer_stamp;      /* Platform time at above system time */
>  static u64 plt_stamp64;          /* 64-bit platform counter stamp           */
>  static u64 plt_stamp;            /* hardware-width platform counter stamp   */
> +static u64 plt_stamp_counter;    /* last read since read_counter */

This can have its scope reduced to within read_platform_stime()

>  static struct timer plt_overflow_timer;
>  
>  static s_time_t __read_platform_stime(u64 platform_time)
> @@ -566,7 +567,7 @@ static void plt_overflow(void *unused)
>      set_timer(&plt_overflow_timer, NOW() + plt_overflow_period);
>  }
>  
> -static s_time_t read_platform_stime(void)
> +static s_time_t read_platform_stime(u64 *stamp)
>  {
>      u64 count;
>      s_time_t stime;
> @@ -574,8 +575,11 @@ static s_time_t read_platform_stime(void)
>      ASSERT(!local_irq_is_enabled());
>  
>      spin_lock(&platform_timer_lock);
> -    count = plt_stamp64 + ((plt_src.read_counter() - plt_stamp) & plt_mask);
> +    plt_stamp_counter = plt_src.read_counter();
> +    count = plt_stamp64 + ((plt_stamp_counter - plt_stamp) & plt_mask);
>      stime = __read_platform_stime(count);
> +    if (stamp)

Spaces.

~Andrew

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