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 <[email protected]>
---
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)
{
- return mc->nobjs;
+ return !!mc->nobjs;
}
void kvm_mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc)
--
2.27.0
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 <[email protected]>
> ---
> 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. 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)
On Tue, Jun 14, 2022 at 8:01 AM Sean Christopherson <[email protected]> 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 <[email protected]>
> > ---
> > 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/[email protected]/
> 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)