Re: [PATCH] xen/arm: Fix rtds scheduler for arm

[Ian Campbell <Ian.Campbell@citrix.com>]

On Mon, 2015-02-02 at 20:03 +0200, Denis Drozdov wrote:
> From: denys drozdov <denys.drozdov@globallogic.com>
> 
> Make Credit2 and RT schedulers to run on arm platform
> context_saved should be deferred on ARM after IRQs enabled

A better subject+message would be:

        xen/arm: Call context_saved() with interrupts enabled during context switch
        
        This is a requirement of the scheduler interface, violating this
        causes for example with the RT scheduler:
                <insert crash log here>

> Signed-off-by: denys drozdov <denys.drozdov@globallogic.com>

Acked-by: Ian Campbell <ian.campbell@citrix.com>

However I would like an ack from a scheduler person (e.g. George) before
it gets applied.

> ---
>  xen/arch/arm/domain.c |    7 +++----
>  1 file changed, 3 insertions(+), 4 deletions(-)
> 
> diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
> index 7221bc8..1626376 100644
> --- a/xen/arch/arm/domain.c
> +++ b/xen/arch/arm/domain.c
> @@ -64,7 +64,7 @@ static void ctxt_switch_from(struct vcpu *p)
>       * mode. Therefore we don't need to save the context of an idle VCPU.
>       */
>      if ( is_idle_vcpu(p) )
> -        goto end_context;
> +        return;
>  
>      p2m_save_state(p);
>  
> @@ -138,9 +138,6 @@ static void ctxt_switch_from(struct vcpu *p)
>      gic_save_state(p);
>  
>      isb();
> -
> -end_context:
> -    context_saved(p);
>  }
>  
>  static void ctxt_switch_to(struct vcpu *n)
> @@ -246,6 +243,8 @@ static void schedule_tail(struct vcpu *prev)
>  
>      local_irq_enable();
>  
> +    context_saved(prev);
> +
>      if ( prev != current )
>          update_runstate_area(current);
>