kvm, mm: account kvm related kmem slabs to kmemcg

The kvm slabs can consume a significant amount of system memory
and indeed in our production environment we have observed that
a lot of machines are spending significant amount of memory that
can not be left as system memory overhead. Also the allocations
from these slabs can be triggered directly by user space applications
which has access to kvm and thus a buggy application can leak
such memory. So, these caches should be accounted to kmemcg.
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/mmu.c

@@ -5475,13 +5475,13 @@ int kvm_mmu_module_init(void)
 
 	pte_list_desc_cache = kmem_cache_create("pte_list_desc",
 					    sizeof(struct pte_list_desc),
-					    0, 0, NULL);
+					    0, SLAB_ACCOUNT, NULL);
 	if (!pte_list_desc_cache)
 		goto nomem;
 
 	mmu_page_header_cache = kmem_cache_create("kvm_mmu_page_header",
 						  sizeof(struct kvm_mmu_page),
-						  0, 0, NULL);
+						  0, SLAB_ACCOUNT, NULL);
 	if (!mmu_page_header_cache)
 		goto nomem;
 

virt/kvm/kvm_main.c

@@ -4010,7 +4010,7 @@ int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align,
 	if (!vcpu_align)
 		vcpu_align = __alignof__(struct kvm_vcpu);
 	kvm_vcpu_cache = kmem_cache_create("kvm_vcpu", vcpu_size, vcpu_align,
-					   0, NULL);
+					   SLAB_ACCOUNT, NULL);
 	if (!kvm_vcpu_cache) {
 		r = -ENOMEM;
 		goto out_free_3;