[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>

3 files changed, 5 insertions, 7 deletions

diff --git a/fs/exec.c b/fs/exec.c
index d2208f7c87db..cefadf5ab83b 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -330,7 +330,7 @@ void install_arg_page(struct vm_area_struct *vma,
                 pte_unmap(pte);
                 goto out;
         }
-        inc_mm_counter(mm, rss);
+        inc_mm_counter(mm, anon_rss);
         lru_cache_add_active(page);
         set_pte_at(mm, address, pte, pte_mkdirty(pte_mkwrite(mk_pte(
                                         page, vma->vm_page_prot))));
diff --git a/fs/proc/array.c b/fs/proc/array.c
index d84eecacbeaf..3e1239e4b303 100644
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -438,7 +438,7 @@ static int do_task_stat(struct task_struct *task, char * buffer, int whole)
                 jiffies_to_clock_t(it_real_value),
                 start_time,
                 vsize,
-                mm ? get_mm_counter(mm, rss) : 0, /* you might want to shift this left 3 */
+                mm ? get_mm_rss(mm) : 0,
                 rsslim,
                 mm ? mm->start_code : 0,
                 mm ? mm->end_code : 0,
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 994612bc72d0..bccee7cf9ccd 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -29,7 +29,7 @@ char *task_mem(struct mm_struct *mm, char *buffer)
                 "VmPTE:\t%8lu kB\n",
                 (mm->total_vm - mm->reserved_vm) << (PAGE_SHIFT-10),
                 mm->locked_vm << (PAGE_SHIFT-10),
-                get_mm_counter(mm, rss) << (PAGE_SHIFT-10),
+                get_mm_rss(mm) << (PAGE_SHIFT-10),
                 data << (PAGE_SHIFT-10),
                 mm->stack_vm << (PAGE_SHIFT-10), text, lib,
                 (PTRS_PER_PTE*sizeof(pte_t)*mm->nr_ptes) >> 10);
@@ -44,13 +44,11 @@ unsigned long task_vsize(struct mm_struct *mm)
 int task_statm(struct mm_struct *mm, int *shared, int *text,
                int *data, int *resident)
 {
-        int rss = get_mm_counter(mm, rss);
-
-        *shared = rss - get_mm_counter(mm, anon_rss);
+        *shared = get_mm_counter(mm, file_rss);
         *text = (PAGE_ALIGN(mm->end_code) - (mm->start_code & PAGE_MASK))
                                                                 >> PAGE_SHIFT;
         *data = mm->total_vm - mm->shared_vm;
-        *resident = rss;
+        *resident = *shared + get_mm_counter(mm, anon_rss);
         return mm->total_vm;
 }