Page tables can bite a relatively big chunk off system memory and their
allocations are easy to trigger from userspace, so they should be
accounted to kmemcg.
This patch marks page table allocations as __GFP_ACCOUNT for x86. Note
we must not charge allocations of kernel page tables, because they can
be shared among processes from different cgroups so accounting them to a
particular one can pin other cgroups for indefinitely long. So we clear
__GFP_ACCOUNT flag if a page table is allocated for the kernel.
Signed-off-by: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
---
arch/x86/include/asm/pgalloc.h | 12 ++++++++++--
arch/x86/mm/pgtable.c | 11 ++++++++---
2 files changed, 18 insertions(+), 5 deletions(-)
diff --git a/arch/x86/include/asm/pgalloc.h b/arch/x86/include/asm/pgalloc.h
index bf7f8b55b0f9..2f531633cb16 100644
--- a/arch/x86/include/asm/pgalloc.h
+++ b/arch/x86/include/asm/pgalloc.h
@@ -81,7 +81,11 @@ 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);
+ gfp_t gfp = GFP_KERNEL_ACCOUNT | __GFP_REPEAT | __GFP_ZERO;
+
+ if (mm == &init_mm)
+ gfp &= ~__GFP_ACCOUNT;
+ page = alloc_pages(gfp, 0);
if (!page)
return NULL;
if (!pgtable_pmd_page_ctor(page)) {
@@ -125,7 +129,11 @@ 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);
+ gfp_t gfp = GFP_KERNEL_ACCOUNT | __GFP_REPEAT;
+
+ if (mm == &init_mm)
+ gfp &= ~__GFP_ACCOUNT;
+ return (pud_t *)get_zeroed_page(gfp);
}
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 4eb287e25043..421ac6b74d11 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -6,7 +6,8 @@
#include <asm/fixmap.h>
#include <asm/mtrr.h>
-#define PGALLOC_GFP GFP_KERNEL | __GFP_NOTRACK | __GFP_REPEAT | __GFP_ZERO
+#define PGALLOC_GFP (GFP_KERNEL_ACCOUNT | __GFP_NOTRACK | __GFP_REPEAT | \
+ __GFP_ZERO)
#ifdef CONFIG_HIGHPTE
#define PGALLOC_USER_GFP __GFP_HIGHMEM
@@ -18,7 +19,7 @@ gfp_t __userpte_alloc_gfp = PGALLOC_GFP | PGALLOC_USER_GFP;
pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
{
- return (pte_t *)__get_free_page(PGALLOC_GFP);
+ return (pte_t *)__get_free_page(PGALLOC_GFP & ~__GFP_ACCOUNT);
}
pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address)
@@ -207,9 +208,13 @@ static int preallocate_pmds(struct mm_struct *mm, pmd_t *pmds[])
{
int i;
bool failed = false;
+ gfp_t gfp = PGALLOC_GFP;
+
+ if (mm == &init_mm)
+ gfp &= ~__GFP_ACCOUNT;
for(i = 0; i < PREALLOCATED_PMDS; i++) {
- pmd_t *pmd = (pmd_t *)__get_free_page(PGALLOC_GFP);
+ pmd_t *pmd = (pmd_t *)__get_free_page(gfp);
if (!pmd)
failed = true;
if (pmd && !pgtable_pmd_page_ctor(virt_to_page(pmd))) {
--
2.1.4
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