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Subject[Patch v3 8/9] KVM: x86/mmu: Make split_shadow_page_cache NUMA aware
From
Make split_shadow_page_cache NUMA aware and allocate page table's pages
during the split based on the underlying physical page's NUMA node.

Signed-off-by: Vipin Sharma <vipinsh@google.com>
---
arch/x86/include/asm/kvm_host.h | 2 +-
arch/x86/kvm/mmu/mmu.c | 50 ++++++++++++++++++---------------
2 files changed, 29 insertions(+), 23 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index b1f319ad6f89..7b3f36ae37a4 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1410,7 +1410,7 @@ struct kvm_arch {
*
* Protected by kvm->slots_lock.
*/
- struct kvm_mmu_memory_cache split_shadow_page_cache;
+ struct kvm_mmu_memory_cache split_shadow_page_cache[MAX_NUMNODES];
struct kvm_mmu_memory_cache split_page_header_cache;

/*
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 511c6ef265ee..7454bfc49a51 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -6126,7 +6126,7 @@ static void kvm_mmu_invalidate_zap_pages_in_memslot(struct kvm *kvm,
int kvm_mmu_init_vm(struct kvm *kvm)
{
struct kvm_page_track_notifier_node *node = &kvm->arch.mmu_sp_tracker;
- int r;
+ int r, nid;

INIT_LIST_HEAD(&kvm->arch.active_mmu_pages);
INIT_LIST_HEAD(&kvm->arch.possible_nx_huge_pages);
@@ -6145,8 +6145,9 @@ int kvm_mmu_init_vm(struct kvm *kvm)
INIT_KVM_MMU_MEMORY_CACHE(&kvm->arch.split_page_header_cache,
mmu_page_header_cache, NUMA_NO_NODE);

- INIT_KVM_MMU_MEMORY_CACHE(&kvm->arch.split_shadow_page_cache,
- NULL, NUMA_NO_NODE);
+ for_each_node(nid)
+ INIT_KVM_MMU_MEMORY_CACHE(&kvm->arch.split_shadow_page_cache[nid],
+ NULL, NUMA_NO_NODE);
spin_lock_init(&kvm->arch.split_shadow_page_cache_lock);

INIT_KVM_MMU_MEMORY_CACHE(&kvm->arch.split_desc_cache,
@@ -6157,10 +6158,13 @@ int kvm_mmu_init_vm(struct kvm *kvm)

static void mmu_free_vm_memory_caches(struct kvm *kvm)
{
+ int nid;
+
kvm_mmu_free_memory_cache(&kvm->arch.split_desc_cache);
kvm_mmu_free_memory_cache(&kvm->arch.split_page_header_cache);
- mmu_free_sp_memory_cache(&kvm->arch.split_shadow_page_cache,
- &kvm->arch.split_shadow_page_cache_lock);
+ for_each_node(nid)
+ mmu_free_sp_memory_cache(&kvm->arch.split_shadow_page_cache[nid],
+ &kvm->arch.split_shadow_page_cache_lock);
}

void kvm_mmu_uninit_vm(struct kvm *kvm)
@@ -6269,7 +6273,7 @@ static inline bool need_topup(struct kvm_mmu_memory_cache *cache, int min)
return kvm_mmu_memory_cache_nr_free_objects(cache) < min;
}

-static bool need_topup_split_caches_or_resched(struct kvm *kvm)
+static bool need_topup_split_caches_or_resched(struct kvm *kvm, int nid)
{
if (need_resched() || rwlock_needbreak(&kvm->mmu_lock))
return true;
@@ -6281,10 +6285,10 @@ static bool need_topup_split_caches_or_resched(struct kvm *kvm)
*/
return need_topup(&kvm->arch.split_desc_cache, SPLIT_DESC_CACHE_MIN_NR_OBJECTS) ||
need_topup(&kvm->arch.split_page_header_cache, 1) ||
- need_topup(&kvm->arch.split_shadow_page_cache, 1);
+ need_topup(&kvm->arch.split_shadow_page_cache[nid], 1);
}

-static int topup_split_caches(struct kvm *kvm)
+static int topup_split_caches(struct kvm *kvm, int nid)
{
/*
* Allocating rmap list entries when splitting huge pages for nested
@@ -6314,18 +6318,21 @@ static int topup_split_caches(struct kvm *kvm)
if (r)
return r;

- return mmu_topup_sp_memory_cache(&kvm->arch.split_shadow_page_cache,
+ return mmu_topup_sp_memory_cache(&kvm->arch.split_shadow_page_cache[nid],
&kvm->arch.split_shadow_page_cache_lock,
1);
}

-static struct kvm_mmu_page *shadow_mmu_get_sp_for_split(struct kvm *kvm, u64 *huge_sptep)
+static struct kvm_mmu_page *shadow_mmu_get_sp_for_split(struct kvm *kvm,
+ u64 *huge_sptep,
+ u64 huge_spte)
{
struct kvm_mmu_page *huge_sp = sptep_to_sp(huge_sptep);
struct shadow_page_caches caches = {};
union kvm_mmu_page_role role;
unsigned int access;
gfn_t gfn;
+ int nid;

gfn = kvm_mmu_page_get_gfn(huge_sp, spte_index(huge_sptep));
access = kvm_mmu_page_get_access(huge_sp, spte_index(huge_sptep));
@@ -6338,9 +6345,11 @@ static struct kvm_mmu_page *shadow_mmu_get_sp_for_split(struct kvm *kvm, u64 *hu
*/
role = kvm_mmu_child_role(huge_sptep, /*direct=*/true, access);

+ nid = kvm_pfn_to_page_table_nid(spte_to_pfn(huge_spte));
+
/* Direct SPs do not require a shadowed_info_cache. */
caches.page_header_cache = &kvm->arch.split_page_header_cache;
- caches.shadow_page_cache = &kvm->arch.split_shadow_page_cache;
+ caches.shadow_page_cache = &kvm->arch.split_shadow_page_cache[nid];
caches.shadow_page_cache_lock = &kvm->arch.split_shadow_page_cache_lock;

/* Safe to pass NULL for vCPU since requesting a direct SP. */
@@ -6360,7 +6369,7 @@ static void shadow_mmu_split_huge_page(struct kvm *kvm,
gfn_t gfn;
int index;

- sp = shadow_mmu_get_sp_for_split(kvm, huge_sptep);
+ sp = shadow_mmu_get_sp_for_split(kvm, huge_sptep, huge_spte);

for (index = 0; index < SPTE_ENT_PER_PAGE; index++) {
sptep = &sp->spt[index];
@@ -6398,7 +6407,7 @@ static int shadow_mmu_try_split_huge_page(struct kvm *kvm,
u64 *huge_sptep)
{
struct kvm_mmu_page *huge_sp = sptep_to_sp(huge_sptep);
- int level, r = 0;
+ int level, r = 0, nid;
gfn_t gfn;
u64 spte;

@@ -6406,13 +6415,14 @@ static int shadow_mmu_try_split_huge_page(struct kvm *kvm,
gfn = kvm_mmu_page_get_gfn(huge_sp, spte_index(huge_sptep));
level = huge_sp->role.level;
spte = *huge_sptep;
+ nid = kvm_pfn_to_page_table_nid(spte_to_pfn(spte));

if (kvm_mmu_available_pages(kvm) <= KVM_MIN_FREE_MMU_PAGES) {
r = -ENOSPC;
goto out;
}

- if (need_topup_split_caches_or_resched(kvm)) {
+ if (need_topup_split_caches_or_resched(kvm, nid)) {
write_unlock(&kvm->mmu_lock);
cond_resched();
/*
@@ -6420,7 +6430,7 @@ static int shadow_mmu_try_split_huge_page(struct kvm *kvm,
* rmap iterator should be restarted because the MMU lock was
* dropped.
*/
- r = topup_split_caches(kvm) ?: -EAGAIN;
+ r = topup_split_caches(kvm, nid) ?: -EAGAIN;
write_lock(&kvm->mmu_lock);
goto out;
}
@@ -6709,17 +6719,15 @@ void kvm_mmu_invalidate_mmio_sptes(struct kvm *kvm, u64 gen)
}

static unsigned long mmu_shrink_cache(struct kvm_mmu_memory_cache *cache,
- int cache_count,
spinlock_t *cache_lock)
{
unsigned long freed = 0;
int nid;

spin_lock(cache_lock);
- for (nid = 0; nid < cache_count; nid++) {
- if (node_online(nid) && cache[nid].nobjs)
+ for_each_online_node(nid)
+ if (cache[nid].nobjs)
freed += kvm_mmu_empty_memory_cache(&cache[nid]);
- }
spin_unlock(cache_lock);
return freed;
}
@@ -6741,8 +6749,7 @@ mmu_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
first_kvm = kvm;
list_move_tail(&kvm->vm_list, &vm_list);

- freed += mmu_shrink_cache(&kvm->arch.split_shadow_page_cache,
- 1,
+ freed += mmu_shrink_cache(kvm->arch.split_shadow_page_cache,
&kvm->arch.split_shadow_page_cache_lock);

if (freed >= sc->nr_to_scan)
@@ -6750,7 +6757,6 @@ mmu_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)

kvm_for_each_vcpu(i, vcpu, kvm) {
freed += mmu_shrink_cache(vcpu->arch.mmu_shadow_page_cache,
- MAX_NUMNODES,
&vcpu->arch.mmu_shadow_page_cache_lock);
}

--
2.39.0.314.g84b9a713c41-goog
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