Re: [PATCH 5/6] KVM MMU: reduce kvm_mmu_page size

Avi Kivity
2010-04-12T08:36:44Z

On 04/12/2010 11:05 AM, Xiao Guangrong wrote:
> 'multimapped' and 'unsync' in 'struct kvm_mmu_page' are just indication
> field, we can use flag bits instand of them
>
> @@ -202,9 +202,10 @@ struct kvm_mmu_page {
> * in this shadow page.
> */
> DECLARE_BITMAP(slot_bitmap, KVM_MEMORY_SLOTS + KVM_PRIVATE_MEM_SLOTS);
> - int multimapped; /* More than one parent_pte? */
> int root_count; /* Currently serving as active root */
> - bool unsync;
> + #define MMU_PAGE_MULTIMAPPED 0x1 /* More than one parent_pte? */
> + #define MMU_PAGE_UNSYNC 0x2
> + unsigned int flags;
> unsigned int unsync_children;
> union {
>

Please just use bool for multimapped. If we grow more than 4 flags, we
can use 'bool flag : 1;' to reduce space while retaining readability.

--
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.