Thread (3 messages) flat view 3 messages, 2 authors, 2017-02-17

Re: [PATCH v4 1/2] x86/paravirt: Change vcp_is_preempted() arg type to long

From: Peter Zijlstra <peterz@infradead.org>
Date: 2017-02-16 16:09:52
Also in: kvm, linux-arch, lkml

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.
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