[PATCH] mm: rss = file_rss + anon_rss

I was lazy when we added anon_rss, and chose to change as few places as
possible.  So currently each anonymous page has to be counted twice, in rss
and in anon_rss.  Which won't be so good if those are atomic counts in some
configurations.

Change that around: keep file_rss and anon_rss separately, and add them
together (with get_mm_rss macro) when the total is needed - reading two
atomics is much cheaper than updating two atomics.  And update anon_rss
upfront, typically in memory.c, not tucked away in page_add_anon_rmap.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 3 insertions, 3 deletions

diff --git a/kernel/acct.c b/kernel/acct.c
index b756f527497e..2e3f4a47e7d0 100644
--- a/kernel/acct.c
+++ b/kernel/acct.c
@@ -553,7 +553,7 @@ void acct_update_integrals(struct task_struct *tsk)
                 if (delta == 0)
                         return;
                 tsk->acct_stimexpd = tsk->stime;
-                tsk->acct_rss_mem1 += delta * get_mm_counter(tsk->mm, rss);
+                tsk->acct_rss_mem1 += delta * get_mm_rss(tsk->mm);
                 tsk->acct_vm_mem1 += delta * tsk->mm->total_vm;
         }
 }
diff --git a/kernel/fork.c b/kernel/fork.c
index 25caa02e2eac..2048ed7b5872 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -321,7 +321,7 @@ static struct mm_struct * mm_init(struct mm_struct * mm)
         INIT_LIST_HEAD(&mm->mmlist);
         mm->core_waiters = 0;
         mm->nr_ptes = 0;
-        set_mm_counter(mm, rss, 0);
+        set_mm_counter(mm, file_rss, 0);
         set_mm_counter(mm, anon_rss, 0);
         spin_lock_init(&mm->page_table_lock);
         rwlock_init(&mm->ioctx_list_lock);
@@ -499,7 +499,7 @@ static int copy_mm(unsigned long clone_flags, struct task_struct * tsk)
         if (retval)
                 goto free_pt;
 
-        mm->hiwater_rss = get_mm_counter(mm,rss);
+        mm->hiwater_rss = get_mm_rss(mm);
         mm->hiwater_vm = mm->total_vm;
 
 good_mm: