mm: memcontrol: fold move_anon() and move_file()

Turn the move type enum into flags and give the flags field a shorter
name.  Once that is done, move_anon() and move_file() are simple enough to
just fold them into the callsites.

[akpm@linux-foundation.org: tweak MOVE_MASK definition, per Michal]
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Reviewed-by: Vladimir Davydov <vdavydov@parallels.com>
Cc: Greg Thelen <gthelen@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 18 insertions, 31 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index ee97c9ac62c0..11c9e6a1dad5 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -369,21 +369,18 @@ static bool memcg_kmem_is_active(struct mem_cgroup *memcg)
 
 /* Stuffs for move charges at task migration. */
 /*
- * Types of charges to be moved. "move_charge_at_immitgrate" and
- * "immigrate_flags" are treated as a left-shifted bitmap of these types.
+ * Types of charges to be moved.
  */
-enum move_type {
-        MOVE_CHARGE_TYPE_ANON,  /* private anonymous page and swap of it */
-        MOVE_CHARGE_TYPE_FILE,  /* file page(including tmpfs) and swap of it */
-        NR_MOVE_TYPE,
-};
+#define MOVE_ANON       0x1U
+#define MOVE_FILE       0x2U
+#define MOVE_MASK       (MOVE_ANON | MOVE_FILE)
 
 /* "mc" and its members are protected by cgroup_mutex */
 static struct move_charge_struct {
         spinlock_t        lock; /* for from, to */
         struct mem_cgroup *from;
         struct mem_cgroup *to;
-        unsigned long immigrate_flags;
+        unsigned long flags;
         unsigned long precharge;
         unsigned long moved_charge;
         unsigned long moved_swap;
@@ -394,16 +391,6 @@ static struct move_charge_struct {
         .waitq = __WAIT_QUEUE_HEAD_INITIALIZER(mc.waitq),
 };
 
-static bool move_anon(void)
-{
-        return test_bit(MOVE_CHARGE_TYPE_ANON, &mc.immigrate_flags);
-}
-
-static bool move_file(void)
-{
-        return test_bit(MOVE_CHARGE_TYPE_FILE, &mc.immigrate_flags);
-}
-
 /*
  * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft
  * limit reclaim to prevent infinite loops, if they ever occur.
@@ -3500,7 +3487,7 @@ static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css,
 {
         struct mem_cgroup *memcg = mem_cgroup_from_css(css);
 
-        if (val >= (1 << NR_MOVE_TYPE))
+        if (val & ~MOVE_MASK)
                 return -EINVAL;
 
         /*
@@ -4773,12 +4760,12 @@ static struct page *mc_handle_present_pte(struct vm_area_struct *vma,
         if (!page || !page_mapped(page))
                 return NULL;
         if (PageAnon(page)) {
-                /* we don't move shared anon */
-                if (!move_anon())
+                if (!(mc.flags & MOVE_ANON))
                         return NULL;
-        } else if (!move_file())
-                /* we ignore mapcount for file pages */
-                return NULL;
+        } else {
+                if (!(mc.flags & MOVE_FILE))
+                        return NULL;
+        }
         if (!get_page_unless_zero(page))
                 return NULL;
 
@@ -4792,7 +4779,7 @@ static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
         struct page *page = NULL;
         swp_entry_t ent = pte_to_swp_entry(ptent);
 
-        if (!move_anon() || non_swap_entry(ent))
+        if (!(mc.flags & MOVE_ANON) || non_swap_entry(ent))
                 return NULL;
         /*
          * Because lookup_swap_cache() updates some statistics counter,
@@ -4821,7 +4808,7 @@ static struct page *mc_handle_file_pte(struct vm_area_struct *vma,
 
         if (!vma->vm_file) /* anonymous vma */
                 return NULL;
-        if (!move_file())
+        if (!(mc.flags & MOVE_FILE))
                 return NULL;
 
         mapping = vma->vm_file->f_mapping;
@@ -4900,7 +4887,7 @@ static enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma,
 
         page = pmd_page(pmd);
         VM_BUG_ON_PAGE(!page || !PageHead(page), page);
-        if (!move_anon())
+        if (!(mc.flags & MOVE_ANON))
                 return ret;
         if (page->mem_cgroup == mc.from) {
                 ret = MC_TARGET_PAGE;
@@ -5042,15 +5029,15 @@ static int mem_cgroup_can_attach(struct cgroup_subsys_state *css,
         struct task_struct *p = cgroup_taskset_first(tset);
         int ret = 0;
         struct mem_cgroup *memcg = mem_cgroup_from_css(css);
-        unsigned long move_charge_at_immigrate;
+        unsigned long move_flags;
 
         /*
          * We are now commited to this value whatever it is. Changes in this
          * tunable will only affect upcoming migrations, not the current one.
          * So we need to save it, and keep it going.
          */
-        move_charge_at_immigrate  = memcg->move_charge_at_immigrate;
-        if (move_charge_at_immigrate) {
+        move_flags = ACCESS_ONCE(memcg->move_charge_at_immigrate);
+        if (move_flags) {
                 struct mm_struct *mm;
                 struct mem_cgroup *from = mem_cgroup_from_task(p);
 
@@ -5070,7 +5057,7 @@ static int mem_cgroup_can_attach(struct cgroup_subsys_state *css,
                         spin_lock(&mc.lock);
                         mc.from = from;
                         mc.to = memcg;
-                        mc.immigrate_flags = move_charge_at_immigrate;
+                        mc.flags = move_flags;
                         spin_unlock(&mc.lock);
                         /* We set mc.moving_task later */