kvm, mm: account shadow page tables to kmemcg

The size of kvm's shadow page tables corresponds to the size of the
guest virtual machines on the system.  Large VMs can spend a significant
amount of memory as shadow page tables which can not be left as system
memory overhead.  So, account shadow page tables to the kmemcg.

[[email protected]: replace (GFP_KERNEL|__GFP_ACCOUNT) with GFP_KERNEL_ACCOUNT]
  Link: http://lkml.kernel.org/r/[email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Shakeel Butt <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Vladimir Davydov <[email protected]>
Cc: Paolo Bonzini <[email protected]>
Cc: Greg Thelen <[email protected]>
Cc: Radim Krčmář <[email protected]>
Cc: Peter Feiner <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

arch/x86/kvm/mmu.c

@@ -890,7 +890,7 @@ static int mmu_topup_memory_cache_page(struct kvm_mmu_memory_cache *cache,
 	if (cache->nobjs >= min)
 		return 0;
 	while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
-		page = (void *)__get_free_page(GFP_KERNEL);
+		page = (void *)__get_free_page(GFP_KERNEL_ACCOUNT);
 		if (!page)
 			return -ENOMEM;
 		cache->objects[cache->nobjs++] = page;