Re: [Patch v3 6/9] KVM: Provide NUMA node support to kvm_mmu_memory_cache{}

From: David Matlack
Date: Thu Dec 29 2022 - 18:12:12 EST

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On Thu, Dec 29, 2022 at 3:08 PM David Matlack <dmatlack@xxxxxxxxxx> wrote:
>
> On Wed, Dec 21, 2022 at 06:34:54PM -0800, Vipin Sharma wrote:
> > Add 'node' variable in kvm_mmu_memory_cache{} to denote which NUMA node
> > this cache should allocate memory from. Default initialize to
> > NUMA_NO_NODE in all architectures.
> >
> > Signed-off-by: Vipin Sharma <vipinsh@xxxxxxxxxx>
> > ---
> > arch/arm64/kvm/arm.c | 2 +-
> > arch/arm64/kvm/mmu.c | 4 +++-
> > arch/mips/kvm/mips.c | 2 ++
> > arch/riscv/kvm/mmu.c | 2 +-
> > arch/riscv/kvm/vcpu.c | 2 +-
> > arch/x86/kvm/mmu/mmu.c | 22 ++++++++++++----------
> > include/linux/kvm_host.h | 6 ++++++
> > include/linux/kvm_types.h | 2 ++
> > 8 files changed, 28 insertions(+), 14 deletions(-)
> >
> > diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
> > index 9c5573bc4614..52a41f4532e2 100644
> > --- a/arch/arm64/kvm/arm.c
> > +++ b/arch/arm64/kvm/arm.c
> > @@ -340,7 +340,7 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
> > vcpu->arch.target = -1;
> > bitmap_zero(vcpu->arch.features, KVM_VCPU_MAX_FEATURES);
> >
> > - vcpu->arch.mmu_page_cache.gfp_zero = __GFP_ZERO;
> > + INIT_KVM_MMU_MEMORY_CACHE(&vcpu->arch.mmu_page_cache, NULL, NUMA_NO_NODE);
> >
> > /*
> > * Default value for the FP state, will be overloaded at load
> > diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
> > index 31d7fa4c7c14..bd07155e17fa 100644
> > --- a/arch/arm64/kvm/mmu.c
> > +++ b/arch/arm64/kvm/mmu.c
> > @@ -894,12 +894,14 @@ int kvm_phys_addr_ioremap(struct kvm *kvm, phys_addr_t guest_ipa,
> > {
> > phys_addr_t addr;
> > int ret = 0;
> > - struct kvm_mmu_memory_cache cache = { .gfp_zero = __GFP_ZERO };
> > + struct kvm_mmu_memory_cache cache;
> > struct kvm_pgtable *pgt = kvm->arch.mmu.pgt;
> > enum kvm_pgtable_prot prot = KVM_PGTABLE_PROT_DEVICE |
> > KVM_PGTABLE_PROT_R |
> > (writable ? KVM_PGTABLE_PROT_W : 0);
> >
> > + INIT_KVM_MMU_MEMORY_CACHE(&cache, NULL, NUMA_NO_NODE);
>
> This is not any better than setting cache.node = NUMA_NO_NODE directly.
> Yes it's less lines of code, but it's harder to read (what does NULL
> mean here?), and every user of kvm_mmu_memory_cache still has to know to
> pass NUMA_NO_NODE.
>
> When I originally gave this suggestion, I intended to suggest that
> INIT_KVM_MMU_MEMORY_CACHE() provide just default initialization.
> Non-default initialization for gfp_zero, gfp_custom, kmem_cache, and
> node would remain as they are.
>
> Yes this adds some more lines, but keeps things readable, and doesn't
> every initialization site of kvm_mmu_memory_cache to know what to pass
> for gfp_zero, node, and kmem_cache. It only needs to set the fields
> *it* cares about.

And to offset the extra lines to call INIT_KVM_MMU_MEMORY_CACHE(), we
could finally invert the meaning of gfp_zero so that caches use
__GFP_ZERO by default. The majority of caches want __GFP_ZERO, so that
should cut down a bunch of lines.

>
> Here's what I mean specifically, based on INIT_LIST_HEAD. I don't think
> I got all the kvm_mmu_memory_cache users, but you get the point.
>
>
> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
> index 9c5573bc4614..0e138dcaf4d4 100644
> --- a/arch/arm64/kvm/arm.c
> +++ b/arch/arm64/kvm/arm.c
> @@ -340,6 +340,7 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
> vcpu->arch.target = -1;
> bitmap_zero(vcpu->arch.features, KVM_VCPU_MAX_FEATURES);
>
> + INIT_KVM_MMU_MEMORY_CACHE(&vcpu->arch.mmu_page_cache);
> vcpu->arch.mmu_page_cache.gfp_zero = __GFP_ZERO;
>
> /*
> diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
> index 31d7fa4c7c14..f5fd78a4f084 100644
> --- a/arch/arm64/kvm/mmu.c
> +++ b/arch/arm64/kvm/mmu.c
> @@ -894,12 +894,14 @@ int kvm_phys_addr_ioremap(struct kvm *kvm, phys_addr_t guest_ipa,
> {
> phys_addr_t addr;
> int ret = 0;
> - struct kvm_mmu_memory_cache cache = { .gfp_zero = __GFP_ZERO };
> + KVM_MMU_MEMORY_CACHE(cache);
> struct kvm_pgtable *pgt = kvm->arch.mmu.pgt;
> enum kvm_pgtable_prot prot = KVM_PGTABLE_PROT_DEVICE |
> KVM_PGTABLE_PROT_R |
> (writable ? KVM_PGTABLE_PROT_W : 0);
>
> + cache.gfp_zero = __GFP_ZERO;
> +
> if (is_protected_kvm_enabled())
> return -EPERM;
>
> diff --git a/arch/riscv/kvm/mmu.c b/arch/riscv/kvm/mmu.c
> index 34b57e0be2ef..7915a5a2d104 100644
> --- a/arch/riscv/kvm/mmu.c
> +++ b/arch/riscv/kvm/mmu.c
> @@ -351,10 +351,11 @@ int kvm_riscv_gstage_ioremap(struct kvm *kvm, gpa_t gpa,
> int ret = 0;
> unsigned long pfn;
> phys_addr_t addr, end;
> - struct kvm_mmu_memory_cache pcache = {
> - .gfp_custom = (in_atomic) ? GFP_ATOMIC | __GFP_ACCOUNT : 0,
> - .gfp_zero = __GFP_ZERO,
> - };
> + KVM_MMU_MEMORY_CACHE(pcache);
> +
> + pcache.gfp_zero = __GFP_ZERO;
> + if (in_atomic)
> + pcache.gfp_custom = GFP_ATOMIC | __GFP_ACCOUNT;
>
> end = (gpa + size + PAGE_SIZE - 1) & PAGE_MASK;
> pfn = __phys_to_pfn(hpa);
> diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c
> index 7c08567097f0..3d73ab3ec9a4 100644
> --- a/arch/riscv/kvm/vcpu.c
> +++ b/arch/riscv/kvm/vcpu.c
> @@ -161,6 +161,7 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
>
> /* Mark this VCPU never ran */
> vcpu->arch.ran_atleast_once = false;
> + INIT_KVM_MMU_MEMORY_CACHE(&vcpu->arch.mmu_page_header_cache);
> vcpu->arch.mmu_page_cache.gfp_zero = __GFP_ZERO;
> bitmap_zero(vcpu->arch.isa, RISCV_ISA_EXT_MAX);
>
> diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> index 254bc46234e0..d4cd8e64cc03 100644
> --- a/arch/x86/kvm/mmu/mmu.c
> +++ b/arch/x86/kvm/mmu/mmu.c
> @@ -5909,14 +5909,19 @@ int kvm_mmu_create(struct kvm_vcpu *vcpu)
> {
> int ret;
>
> + INIT_KVM_MMU_MEMORY_CACHE(&vcpu->arch.mmu_pte_list_desc_cache);
> vcpu->arch.mmu_pte_list_desc_cache.kmem_cache = pte_list_desc_cache;
> vcpu->arch.mmu_pte_list_desc_cache.gfp_zero = __GFP_ZERO;
>
> + INIT_KVM_MMU_MEMORY_CACHE(&vcpu->arch.mmu_page_header_cache);
> vcpu->arch.mmu_page_header_cache.kmem_cache = mmu_page_header_cache;
> vcpu->arch.mmu_page_header_cache.gfp_zero = __GFP_ZERO;
>
> + INIT_KVM_MMU_MEMORY_CACHE(&vcpu->arch.mmu_shadow_page_cache);
> vcpu->arch.mmu_shadow_page_cache.gfp_zero = __GFP_ZERO;
>
> + INIT_KVM_MMU_MEMORY_CACHE(&vcpu->arch.mmu_shadowed_info_cache);
> +
> vcpu->arch.mmu = &vcpu->arch.root_mmu;
> vcpu->arch.walk_mmu = &vcpu->arch.root_mmu;
>
> @@ -6083,11 +6088,14 @@ int kvm_mmu_init_vm(struct kvm *kvm)
> node->track_flush_slot = kvm_mmu_invalidate_zap_pages_in_memslot;
> kvm_page_track_register_notifier(kvm, node);
>
> + INIT_KVM_MMU_MEMORY_CACHE(&kvm->arch.split_page_header_cache);
> kvm->arch.split_page_header_cache.kmem_cache = mmu_page_header_cache;
> kvm->arch.split_page_header_cache.gfp_zero = __GFP_ZERO;
>
> + INIT_KVM_MMU_MEMORY_CACHE(&kvm->arch.split_shadow_page_cache);
> kvm->arch.split_shadow_page_cache.gfp_zero = __GFP_ZERO;
>
> + INIT_KVM_MMU_MEMORY_CACHE(&kvm->arch.split_desc_cache);
> kvm->arch.split_desc_cache.kmem_cache = pte_list_desc_cache;
> kvm->arch.split_desc_cache.gfp_zero = __GFP_ZERO;
>
> diff --git a/include/linux/kvm_types.h b/include/linux/kvm_types.h
> index 76de36e56cdf..eb7ff9afa5c7 100644
> --- a/include/linux/kvm_types.h
> +++ b/include/linux/kvm_types.h
> @@ -98,6 +98,17 @@ struct kvm_mmu_memory_cache {
> int capacity;
> void **objects;
> };
> +
> +#define KVM_MMU_MEMORY_CACHE_INIT() (struct kvm_mmu_memory_cache) { \
> +}
> +
> +#define KVM_MMU_MEMORY_CACHE(_name) \
> + struct kvm_mmu_memory_cache _name = KVM_MMU_MEMORY_CACHE_INIT()
> +
> +static inline void INIT_KVM_MMU_MEMORY_CACHE(struct kvm_mmu_memory_cache *cache)
> +{
> + *cache = KVM_MMU_MEMORY_CACHE_INIT();
> +}
> #endif
>
> #define HALT_POLL_HIST_COUNT 32
>
> > +
> > if (is_protected_kvm_enabled())
> > return -EPERM;
> >
> > diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
> > index a25e0b73ee70..b017c29a9340 100644
> > --- a/arch/mips/kvm/mips.c
> > +++ b/arch/mips/kvm/mips.c
> > @@ -304,6 +304,8 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
> > HRTIMER_MODE_REL);
> > vcpu->arch.comparecount_timer.function = kvm_mips_comparecount_wakeup;
> >
> > + vcpu->arch.mmu_page_cache.node = NUMA_NO_NODE;
> > +
> > /*
> > * Allocate space for host mode exception handlers that handle
> > * guest mode exits
> > diff --git a/arch/riscv/kvm/mmu.c b/arch/riscv/kvm/mmu.c
> > index 34b57e0be2ef..119de4520cc6 100644
> > --- a/arch/riscv/kvm/mmu.c
> > +++ b/arch/riscv/kvm/mmu.c
> > @@ -353,9 +353,9 @@ int kvm_riscv_gstage_ioremap(struct kvm *kvm, gpa_t gpa,
> > phys_addr_t addr, end;
> > struct kvm_mmu_memory_cache pcache = {
> > .gfp_custom = (in_atomic) ? GFP_ATOMIC | __GFP_ACCOUNT : 0,
> > - .gfp_zero = __GFP_ZERO,
> > };
> >
> > + INIT_KVM_MMU_MEMORY_CACHE(&pcache, NULL, NUMA_NO_NODE);
> > end = (gpa + size + PAGE_SIZE - 1) & PAGE_MASK;
> > pfn = __phys_to_pfn(hpa);
> >
> > diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c
> > index 7c08567097f0..189b14feb365 100644
> > --- a/arch/riscv/kvm/vcpu.c
> > +++ b/arch/riscv/kvm/vcpu.c
> > @@ -161,7 +161,7 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
> >
> > /* Mark this VCPU never ran */
> > vcpu->arch.ran_atleast_once = false;
> > - vcpu->arch.mmu_page_cache.gfp_zero = __GFP_ZERO;
> > + INIT_KVM_MMU_MEMORY_CACHE(&vcpu->arch.mmu_page_cache, NULL, NUMA_NO_NODE);
> > bitmap_zero(vcpu->arch.isa, RISCV_ISA_EXT_MAX);
> >
> > /* Setup ISA features available to VCPU */
> > diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> > index 6f6a10d7a871..23a3b82b2384 100644
> > --- a/arch/x86/kvm/mmu/mmu.c
> > +++ b/arch/x86/kvm/mmu/mmu.c
> > @@ -5954,13 +5954,14 @@ int kvm_mmu_create(struct kvm_vcpu *vcpu)
> > {
> > int ret;
> >
> > - vcpu->arch.mmu_pte_list_desc_cache.kmem_cache = pte_list_desc_cache;
> > - vcpu->arch.mmu_pte_list_desc_cache.gfp_zero = __GFP_ZERO;
> > + INIT_KVM_MMU_MEMORY_CACHE(&vcpu->arch.mmu_pte_list_desc_cache,
> > + pte_list_desc_cache, NUMA_NO_NODE);
> >
> > - vcpu->arch.mmu_page_header_cache.kmem_cache = mmu_page_header_cache;
> > - vcpu->arch.mmu_page_header_cache.gfp_zero = __GFP_ZERO;
> > + INIT_KVM_MMU_MEMORY_CACHE(&vcpu->arch.mmu_page_header_cache,
> > + mmu_page_header_cache, NUMA_NO_NODE);
> >
> > - vcpu->arch.mmu_shadow_page_cache.gfp_zero = __GFP_ZERO;
> > + INIT_KVM_MMU_MEMORY_CACHE(&vcpu->arch.mmu_shadow_page_cache,
> > + NULL, NUMA_NO_NODE);
> > spin_lock_init(&vcpu->arch.mmu_shadow_page_cache_lock);
> >
> > vcpu->arch.mmu = &vcpu->arch.root_mmu;
> > @@ -6124,14 +6125,15 @@ int kvm_mmu_init_vm(struct kvm *kvm)
> > node->track_flush_slot = kvm_mmu_invalidate_zap_pages_in_memslot;
> > kvm_page_track_register_notifier(kvm, node);
> >
> > - kvm->arch.split_page_header_cache.kmem_cache = mmu_page_header_cache;
> > - kvm->arch.split_page_header_cache.gfp_zero = __GFP_ZERO;
> > + INIT_KVM_MMU_MEMORY_CACHE(&kvm->arch.split_page_header_cache,
> > + mmu_page_header_cache, NUMA_NO_NODE);
> >
> > - kvm->arch.split_shadow_page_cache.gfp_zero = __GFP_ZERO;
> > + INIT_KVM_MMU_MEMORY_CACHE(&kvm->arch.split_shadow_page_cache,
> > + NULL, NUMA_NO_NODE);
> > spin_lock_init(&kvm->arch.split_shadow_page_cache_lock);
> >
> > - kvm->arch.split_desc_cache.kmem_cache = pte_list_desc_cache;
> > - kvm->arch.split_desc_cache.gfp_zero = __GFP_ZERO;
> > + INIT_KVM_MMU_MEMORY_CACHE(&kvm->arch.split_desc_cache,
> > + pte_list_desc_cache, NUMA_NO_NODE);
> >
> > return 0;
> > }
> > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> > index a262e15ebd19..719687a37ef7 100644
> > --- a/include/linux/kvm_host.h
> > +++ b/include/linux/kvm_host.h
> > @@ -2302,4 +2302,10 @@ static inline void kvm_account_pgtable_pages(void *virt, int nr)
> > /* Max number of entries allowed for each kvm dirty ring */
> > #define KVM_DIRTY_RING_MAX_ENTRIES 65536
> >
> > +#define INIT_KVM_MMU_MEMORY_CACHE(_cache, _kmem_cache, _node) ({ \
> > + (_cache)->kmem_cache = _kmem_cache; \
> > + (_cache)->gfp_zero = __GFP_ZERO; \
> > + (_cache)->node = _node; \
> > +})
> > +
> > #endif
> > diff --git a/include/linux/kvm_types.h b/include/linux/kvm_types.h
> > index 76de36e56cdf..9c70ce95e51f 100644
> > --- a/include/linux/kvm_types.h
> > +++ b/include/linux/kvm_types.h
> > @@ -97,6 +97,8 @@ struct kvm_mmu_memory_cache {
> > struct kmem_cache *kmem_cache;
> > int capacity;
> > void **objects;
> > + /* Node on which memory should be allocated by default */
> > + int node;
> > };
> > #endif
> >
> > --
> > 2.39.0.314.g84b9a713c41-goog
> >

Next message: Andrew Morton: "Re: [PATCH v3 2/3] mm: vmalloc: Switch to find_unlink_vmap_area() in vm_unmap_ram()"
Previous message: David Matlack: "Re: [Patch v3 6/9] KVM: Provide NUMA node support to kvm_mmu_memory_cache{}"
In reply to: David Matlack: "Re: [Patch v3 6/9] KVM: Provide NUMA node support to kvm_mmu_memory_cache{}"
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