Re: [PATCH v4 1/2] x86/paravirt: Change vcp_is_preempted() arg type to long
From: Peter Zijlstra
Date: Thu Feb 16 2017 - 11:09:54 EST
On Wed, Feb 15, 2017 at 04:37:49PM -0500, Waiman Long wrote:
> The cpu argument in the function prototype of vcpu_is_preempted()
> is changed from int to long. That makes it easier to provide a better
> optimized assembly version of that function.
>
> For Xen, vcpu_is_preempted(long) calls xen_vcpu_stolen(int), the
> downcast from long to int is not a problem as vCPU number won't exceed
> 32 bits.
>
Note that because of the cast in PVOP_CALL_ARG1() this patch is
pointless.
Then again, it doesn't seem to affect code generation, so why not. Takes
away the reliance on that weird cast.