memcg: cleanup preparation for page table walk

pagewalk.c can handle vma in itself, so we don't have to pass vma via
walk->private.  And both of mem_cgroup_count_precharge() and
mem_cgroup_move_charge() do for each vma loop themselves, but now it's
done in pagewalk.c, so let's clean up them.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 16 insertions, 33 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index c7a9cb627180..095c1f96fbec 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4839,7 +4839,7 @@ static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd,
                                         unsigned long addr, unsigned long end,
                                         struct mm_walk *walk)
 {
-        struct vm_area_struct *vma = walk->private;
+        struct vm_area_struct *vma = walk->vma;
         pte_t *pte;
         spinlock_t *ptl;
 
@@ -4865,20 +4865,13 @@ static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd,
 static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm)
 {
         unsigned long precharge;
-        struct vm_area_struct *vma;
 
+        struct mm_walk mem_cgroup_count_precharge_walk = {
+                .pmd_entry = mem_cgroup_count_precharge_pte_range,
+                .mm = mm,
+        };
         down_read(&mm->mmap_sem);
-        for (vma = mm->mmap; vma; vma = vma->vm_next) {
-                struct mm_walk mem_cgroup_count_precharge_walk = {
-                        .pmd_entry = mem_cgroup_count_precharge_pte_range,
-                        .mm = mm,
-                        .private = vma,
-                };
-                if (is_vm_hugetlb_page(vma))
-                        continue;
-                walk_page_range(vma->vm_start, vma->vm_end,
-                                        &mem_cgroup_count_precharge_walk);
-        }
+        walk_page_range(0, ~0UL, &mem_cgroup_count_precharge_walk);
         up_read(&mm->mmap_sem);
 
         precharge = mc.precharge;
@@ -5011,7 +5004,7 @@ static int mem_cgroup_move_charge_pte_range(pmd_t *pmd,
                                 struct mm_walk *walk)
 {
         int ret = 0;
-        struct vm_area_struct *vma = walk->private;
+        struct vm_area_struct *vma = walk->vma;
         pte_t *pte;
         spinlock_t *ptl;
         enum mc_target_type target_type;
@@ -5107,7 +5100,10 @@ put:			/* get_mctgt_type() gets the page */
 
 static void mem_cgroup_move_charge(struct mm_struct *mm)
 {
-        struct vm_area_struct *vma;
+        struct mm_walk mem_cgroup_move_charge_walk = {
+                .pmd_entry = mem_cgroup_move_charge_pte_range,
+                .mm = mm,
+        };
 
         lru_add_drain_all();
         /*
@@ -5130,24 +5126,11 @@ retry:
                 cond_resched();
                 goto retry;
         }
-        for (vma = mm->mmap; vma; vma = vma->vm_next) {
-                int ret;
-                struct mm_walk mem_cgroup_move_charge_walk = {
-                        .pmd_entry = mem_cgroup_move_charge_pte_range,
-                        .mm = mm,
-                        .private = vma,
-                };
-                if (is_vm_hugetlb_page(vma))
-                        continue;
-                ret = walk_page_range(vma->vm_start, vma->vm_end,
-                                                &mem_cgroup_move_charge_walk);
-                if (ret)
-                        /*
-                         * means we have consumed all precharges and failed in
-                         * doing additional charge. Just abandon here.
-                         */
-                        break;
-        }
+        /*
+         * When we have consumed all precharges and failed in doing
+         * additional charge, the page walk just aborts.
+         */
+        walk_page_range(0, ~0UL, &mem_cgroup_move_charge_walk);
         up_read(&mm->mmap_sem);
         atomic_dec(&mc.from->moving_account);
 }