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>

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index ee97c9a..11c9e6a 100644 (file)
--- 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 */