On Tue, Jun 14, 2022 at 8:01 AM Sean Christopherson <seanjc@xxxxxxxxxx> wrote: > > On Tue, Jun 14, 2022, Bo Liu wrote: > > The return value type of the function rmap_can_add() is "bool", and it will > > returns the result of the function kvm_mmu_memory_cache_nr_free_objects(). > > So we should change the return value type of > > kvm_mmu_memory_cache_nr_free_objects() to "bool". > > > > Signed-off-by: Bo Liu <liubo03@xxxxxxxxxx> > > --- > > include/linux/kvm_host.h | 2 +- > > virt/kvm/kvm_main.c | 4 ++-- > > 2 files changed, 3 insertions(+), 3 deletions(-) > > > > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h > > index c20f2d55840c..a399a7485795 100644 > > --- a/include/linux/kvm_host.h > > +++ b/include/linux/kvm_host.h > > @@ -1358,7 +1358,7 @@ void kvm_flush_remote_tlbs(struct kvm *kvm); > > > > #ifdef KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE > > int kvm_mmu_topup_memory_cache(struct kvm_mmu_memory_cache *mc, int min); > > -int kvm_mmu_memory_cache_nr_free_objects(struct kvm_mmu_memory_cache *mc); > > +bool kvm_mmu_memory_cache_nr_free_objects(struct kvm_mmu_memory_cache *mc); > > void kvm_mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc); > > void *kvm_mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc); > > #endif > > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > > index a67e996cbf7f..2872569e3580 100644 > > --- a/virt/kvm/kvm_main.c > > +++ b/virt/kvm/kvm_main.c > > @@ -394,9 +394,9 @@ int kvm_mmu_topup_memory_cache(struct kvm_mmu_memory_cache *mc, int min) > > return 0; > > } > > > > -int kvm_mmu_memory_cache_nr_free_objects(struct kvm_mmu_memory_cache *mc) > > +bool kvm_mmu_memory_cache_nr_free_objects(struct kvm_mmu_memory_cache *mc) > > Absolutely not, the name of the function is "nr_free_objects". Renaming it to > "has_free_objects" is not a net positive IMO. Also nested eager page splitting [1] uses kvm_mmu_memory_cache_nr_free_objects() and needs to know the number of free objects. [1] https://lore.kernel.org/all/20220516232138.1783324-23-dmatlack@xxxxxxxxxx/ > If we really care about returning > a bool then we can tweak rmap_can_add(). > > diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c > index 17252f39bd7c..047855d134da 100644 > --- a/arch/x86/kvm/mmu/mmu.c > +++ b/arch/x86/kvm/mmu/mmu.c > @@ -1018,7 +1018,7 @@ static bool rmap_can_add(struct kvm_vcpu *vcpu) > struct kvm_mmu_memory_cache *mc; > > mc = &vcpu->arch.mmu_pte_list_desc_cache; > - return kvm_mmu_memory_cache_nr_free_objects(mc); > + return !!kvm_mmu_memory_cache_nr_free_objects(mc); > } > > static void rmap_remove(struct kvm *kvm, u64 *spte)
