[PATCH 5/5] x86: charge page table pages to memcg

[Vladimir Davydov <vdavydov@parallels.com>]

As noted in the comment to commit dc6c9a35b66b5 ("mm: account pmd page
tables to the process"), "unprivileged process can allocate significant
amount of memory -- >500 MiB on x86_64 -- and stay unnoticed by
oom-killer and memory cgroup". While the above-mentioned commit fixed
the problem in case of oom-killer, this patch attempts to fix it for
memory cgroup on x86 by making pte_alloc_one and friends use
alloc_kmem_pages instead of alloc_pages so as to charge page table pages
to kmemcg.

Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
---
 arch/x86/include/asm/pgalloc.h | 5 +++--
 arch/x86/mm/pgtable.c          | 8 ++++----
 2 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/arch/x86/include/asm/pgalloc.h b/arch/x86/include/asm/pgalloc.h
index bf7f8b55b0f9..944c543836d5 100644
--- a/arch/x86/include/asm/pgalloc.h
+++ b/arch/x86/include/asm/pgalloc.h
@@ -81,7 +81,7 @@ static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmd,
 static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long addr)
 {
 	struct page *page;
-	page = alloc_pages(GFP_KERNEL | __GFP_REPEAT | __GFP_ZERO, 0);
+	page = alloc_kmem_pages(GFP_KERNEL | __GFP_REPEAT | __GFP_ZERO, 0);
 	if (!page)
 		return NULL;
 	if (!pgtable_pmd_page_ctor(page)) {
@@ -125,7 +125,8 @@ static inline void pgd_populate(struct mm_struct *mm, pgd_t *pgd, pud_t *pud)
 
 static inline pud_t *pud_alloc_one(struct mm_struct *mm, unsigned long addr)
 {
-	return (pud_t *)get_zeroed_page(GFP_KERNEL|__GFP_REPEAT);
+	return (pud_t *)__get_free_kmem_pages(GFP_KERNEL|__GFP_REPEAT|
+					      __GFP_ZERO, 0);
 }
 
 static inline void pud_free(struct mm_struct *mm, pud_t *pud)
diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index fb0a9dd1d6e4..c2f0d57aa7e8 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -25,7 +25,7 @@ pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address)
 {
 	struct page *pte;
 
-	pte = alloc_pages(__userpte_alloc_gfp, 0);
+	pte = alloc_kmem_pages(__userpte_alloc_gfp, 0);
 	if (!pte)
 		return NULL;
 	if (!pgtable_page_ctor(pte)) {
@@ -209,7 +209,7 @@ static int preallocate_pmds(struct mm_struct *mm, pmd_t *pmds[])
 	bool failed = false;
 
 	for(i = 0; i < PREALLOCATED_PMDS; i++) {
-		pmd_t *pmd = (pmd_t *)__get_free_page(PGALLOC_GFP);
+		pmd_t *pmd = (pmd_t *)__get_free_kmem_pages(PGALLOC_GFP, 0);
 		if (!pmd)
 			failed = true;
 		if (pmd && !pgtable_pmd_page_ctor(virt_to_page(pmd))) {
@@ -323,7 +323,7 @@ static inline pgd_t *_pgd_alloc(void)
 	 * We allocate one page for pgd.
 	 */
 	if (!SHARED_KERNEL_PMD)
-		return (pgd_t *)__get_free_page(PGALLOC_GFP);
+		pgd = (pgd_t *)__get_free_kmem_pages(PGALLOC_GFP, 0);
 
 	/*
 	 * Now PAE kernel is not running as a Xen domain. We can allocate
@@ -342,7 +342,7 @@ static inline void _pgd_free(pgd_t *pgd)
 #else
 static inline pgd_t *_pgd_alloc(void)
 {
-	return (pgd_t *)__get_free_page(PGALLOC_GFP);
+	return (pgd_t *)__get_free_kmem_pages(PGALLOC_GFP, 0);
 }
 
 static inline void _pgd_free(pgd_t *pgd)
-- 
2.1.4

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