Messages in this thread | | | Date | Wed, 10 Oct 2018 07:50:26 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH v4 2/2] locking/pvqspinlock, hv: Enable PV qspinlock for Hyper-V |
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* Yi Sun <yi.y.sun@linux.intel.com> wrote:
> On 18-10-09 12:54:27, Ingo Molnar wrote: > > > > * Yi Sun <yi.y.sun@linux.intel.com> wrote: > > > > > Follow PV spinlock mechanism to implement the callback functions > > > to allow the CPU idling and kicking operations on Hyper-V. > > > > > +#if defined(CONFIG_SMP) > > > + smp_ops.smp_prepare_boot_cpu = hv_smp_prepare_boot_cpu; > > > +#endif > > > > What's wrong with using the common pattern of: > > > > #ifdef CONFIG_SMP > > > > ? > > There is no difference between "#ifdef" and "#if defined". I just copied > it from "hv_smp_prepare_boot_cpu()". Do you need me submit a fix patch > after this set is merged?
It's equivalent code, my point was that '#ifdef CONFIG_XYZ' is the shorter, more canonical pattern we use in the kernel most of the time, it's shorter, easier to read. We only use defined() for longer preprocessor directive conditions, and it's a pattern for "there's something more complex here than a simple CONFIG_XYZ dependency".
Anyway, Thomas fixed it up in the latest iteration.
Thanks,
Ingo
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