Re: [Xen-devel] [PATCH v3.1 03/15] xen/x86: allow calling {sh/hap}_set_allocation with the idle domain

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 29.10.16 at 10:59, <roger.pau@xxxxxxxxxx> wrote:
> ... and using the "preempted" parameter. The solution relies on just calling
> softirq_pending if the current domain is the idle domain. If such preemption
> happens, the caller should then call process_pending_softirqs in order to
> drain the pending softirqs, and then call {sh/hap}_set_allocation again to
> continue with it's execution.
> 
> This allows us to call *_set_allocation() when building domain 0.
> 
> Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
> Acked-by: George Dunlap <george.dunlap@xxxxxxxxxx>
> ---
> Cc: George Dunlap <george.dunlap@xxxxxxxxxxxxx>

Cc: Tim

> Cc: Jan Beulich <jbeulich@xxxxxxxx>
> Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> ---
> Changes since v2:
>  - Fix commit message.
> ---
>  xen/arch/x86/mm/hap/hap.c       | 4 +++-
>  xen/arch/x86/mm/shadow/common.c | 4 +++-
>  2 files changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/xen/arch/x86/mm/hap/hap.c b/xen/arch/x86/mm/hap/hap.c
> index f099e94..0645521 100644
> --- a/xen/arch/x86/mm/hap/hap.c
> +++ b/xen/arch/x86/mm/hap/hap.c
> @@ -379,7 +379,9 @@ hap_set_allocation(struct domain *d, unsigned int pages, 
> int *preempted)
>              break;
>  
>          /* Check to see if we need to yield and try again */
> -        if ( preempted && hypercall_preempt_check() )
> +        if ( preempted &&
> +             (is_idle_vcpu(current) ? softirq_pending(smp_processor_id()) :
> +                                      hypercall_preempt_check()) )
>          {
>              *preempted = 1;
>              return 0;
> diff --git a/xen/arch/x86/mm/shadow/common.c 
> b/xen/arch/x86/mm/shadow/common.c
> index 065bdc7..b2e99c2 100644
> --- a/xen/arch/x86/mm/shadow/common.c
> +++ b/xen/arch/x86/mm/shadow/common.c
> @@ -1679,7 +1679,9 @@ static int sh_set_allocation(struct domain *d,
>              break;
>  
>          /* Check to see if we need to yield and try again */
> -        if ( preempted && hypercall_preempt_check() )
> +        if ( preempted &&
> +             (is_idle_vcpu(current) ? softirq_pending(smp_processor_id()) :
> +                                      hypercall_preempt_check()) )
>          {
>              *preempted = 1;
>              return 0;
> -- 
> 2.7.4 (Apple Git-66)



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