On Mon, May 09, 2022, David Matlack wrote:
> On Mon, May 9, 2022 at 9:48 AM Sean Christopherson <seanjc@xxxxxxxxxx> wrote:
> > > +static void kvm_nested_mmu_try_split_huge_pages(struct kvm *kvm,
> > > + const struct kvm_memory_slot *slot,
> > > + gfn_t start, gfn_t end,
> > > + int target_level)
> > > +{
> > > + int level;
> > > +
> > > + /*
> > > + * Split huge pages starting with KVM_MAX_HUGEPAGE_LEVEL and working
> > > + * down to the target level. This ensures pages are recursively split
> > > + * all the way to the target level. There's no need to split pages
> > > + * already at the target level.
> > > + */
> > > + for (level = KVM_MAX_HUGEPAGE_LEVEL; level > target_level; level--) {
> >
> > Unnecessary braces.
>
> The brace is unnecessary, but when the inner statement is split across
> multiple lines I tend to prefer using braces. (That's why I did the
> same in the other patch and you had the same feedback.) I couldn't
> find any guidance about this in CodingStyle so I'm fine with getting
> rid of the braces if that's what you prefer.
The style varies by subsystem, e.g. I believe perf requires braces in this case.
Absent a "hard" rule, I value consistency above all else, e.g. because KVM doesn't
(usually) include the braces, I started looking for the second statement, i.e. the
lack of an opening brace is an indicator (to me at elast) that a loop/if contains
a single statement.
I actually like Golang's forced braces, but mostly because they are 100% mandatory
and so all code is consistent.
> > > + slot_handle_level_range(kvm, slot,
> > > + nested_mmu_try_split_huge_pages,
> > > + level, level, start, end - 1,
> > > + true, false);
> >
> > IMO it's worth running over by 4 chars to drop 2 lines:
>
> Will do.
>
> >
> > for (level = KVM_MAX_HUGEPAGE_LEVEL; level > target_level; level--)
> > slot_handle_level_range(kvm, slot, nested_mmu_try_split_huge_pages,
> > level, level, start, end - 1, true, false);
> > > + }
> > > +}
> > > +
> > > /* Must be called with the mmu_lock held in write-mode. */
> >
> > Add a lockdep assertion, not a comment.
>
> Agreed but this is an existing comment, so better left to a separate patch.
Doh, I mistook the /* for a +.
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