[PATCH RFC 4/9] mm: add methord to charge vmalloc-ed address

[Yafang Shao <laoar.shao@gmail.com>]

This patch adds a methord to charge or uncharge a given vmalloc-ed
address. It is similar to vfree, except that it doesn't touch the
related pages while does account only.

Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
---
 include/linux/slab.h    |  1 +
 include/linux/vmalloc.h |  1 +
 mm/util.c               |  9 +++++++++
 mm/vmalloc.c            | 29 +++++++++++++++++++++++++++++
 4 files changed, 40 insertions(+)

diff --git a/include/linux/slab.h b/include/linux/slab.h
index ae82e23..7173354 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -759,6 +759,7 @@ extern void *kvrealloc(const void *p, size_t oldsize, size_t newsize, gfp_t flag
 		      __alloc_size(3);
 extern void kvfree(const void *addr);
 extern void kvfree_sensitive(const void *addr, size_t len);
+void kvcharge(const void *addr, bool charge);
 
 unsigned int kmem_cache_size(struct kmem_cache *s);
 void __init kmem_cache_init_late(void);
diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
index 880227b..b48d941 100644
--- a/include/linux/vmalloc.h
+++ b/include/linux/vmalloc.h
@@ -161,6 +161,7 @@ void *__vmalloc_node(unsigned long size, unsigned long align, gfp_t gfp_mask,
 
 extern void vfree(const void *addr);
 extern void vfree_atomic(const void *addr);
+void vcharge(const void *addr, bool charge);
 
 extern void *vmap(struct page **pages, unsigned int count,
 			unsigned long flags, pgprot_t prot);
diff --git a/mm/util.c b/mm/util.c
index 7e433690..f5f5e05 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -614,6 +614,15 @@ void kvfree(const void *addr)
 }
 EXPORT_SYMBOL(kvfree);
 
+void kvcharge(const void *addr, bool charge)
+{
+	if (is_vmalloc_addr(addr))
+		vcharge(addr, charge);
+	else
+		kcharge(addr, charge);
+}
+EXPORT_SYMBOL(kvcharge);
+
 /**
  * kvfree_sensitive - Free a data object containing sensitive information.
  * @addr: address of the data object to be freed.
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 4165304..6fc2295 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -2715,6 +2715,35 @@ void vfree(const void *addr)
 }
 EXPORT_SYMBOL(vfree);
 
+void vcharge(const void *addr, bool charge)
+{
+	unsigned int page_order;
+	struct vm_struct *area;
+	int i;
+
+	WARN_ON(!in_task());
+
+	if (!addr)
+		return;
+
+	area = find_vm_area(addr);
+	if (unlikely(!area))
+		return;
+
+	page_order = vm_area_page_order(area);
+	for (i = 0; i < area->nr_pages; i += 1U << page_order) {
+		struct page *page = area->pages[i];
+
+		WARN_ON(!page);
+		if (charge)
+			memcg_kmem_charge_page(page, GFP_KERNEL, page_order);
+		else
+			memcg_kmem_uncharge_page(page, page_order);
+		cond_resched();
+	}
+}
+EXPORT_SYMBOL(vcharge);
+
 /**
  * vunmap - release virtual mapping obtained by vmap()
  * @addr:   memory base address
-- 
1.8.3.1