[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>

12 files changed, 38 insertions, 37 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;
 }
 
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 27519df0f987..afcaac66cbd5 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -254,6 +254,8 @@ extern void arch_unmap_area_topdown(struct mm_struct *, unsigned long);
 #define add_mm_counter(mm, member, value) (mm)->_##member += (value)
 #define inc_mm_counter(mm, member) (mm)->_##member++
 #define dec_mm_counter(mm, member) (mm)->_##member--
+#define get_mm_rss(mm) ((mm)->_file_rss + (mm)->_anon_rss)
+
 typedef unsigned long mm_counter_t;
 
 struct mm_struct {
@@ -286,7 +288,7 @@ struct mm_struct {
         unsigned long exec_vm, stack_vm, reserved_vm, def_flags, nr_ptes;
 
         /* Special counters protected by the page_table_lock */
-        mm_counter_t _rss;
+        mm_counter_t _file_rss;
         mm_counter_t _anon_rss;
 
         unsigned long saved_auxv[AT_VECTOR_SIZE]; /* for /proc/PID/auxv */
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:
diff --git a/mm/fremap.c b/mm/fremap.c
index ab23a0673c35..fd7f2a17ff3e 100644
--- a/mm/fremap.c
+++ b/mm/fremap.c
@@ -39,7 +39,7 @@ static inline void zap_pte(struct mm_struct *mm, struct vm_area_struct *vma,
                                         set_page_dirty(page);
                                 page_remove_rmap(page);
                                 page_cache_release(page);
-                                dec_mm_counter(mm, rss);
+                                dec_mm_counter(mm, file_rss);
                         }
                 }
         } else {
@@ -95,7 +95,7 @@ int install_page(struct mm_struct *mm, struct vm_area_struct *vma,
 
         zap_pte(mm, vma, addr, pte);
 
-        inc_mm_counter(mm,rss);
+        inc_mm_counter(mm, file_rss);
         flush_icache_page(vma, page);
         set_pte_at(mm, addr, pte, mk_pte(page, prot));
         page_add_file_rmap(page);
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 61d380678030..094455bcbbf7 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -286,7 +286,7 @@ int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
                         entry = *src_pte;
                         ptepage = pte_page(entry);
                         get_page(ptepage);
-                        add_mm_counter(dst, rss, HPAGE_SIZE / PAGE_SIZE);
+                        add_mm_counter(dst, file_rss, HPAGE_SIZE / PAGE_SIZE);
                         set_huge_pte_at(dst, addr, dst_pte, entry);
                 }
                 spin_unlock(&src->page_table_lock);
@@ -324,7 +324,7 @@ void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
 
                 page = pte_page(pte);
                 put_page(page);
-                add_mm_counter(mm, rss,  - (HPAGE_SIZE / PAGE_SIZE));
+                add_mm_counter(mm, file_rss, (int) -(HPAGE_SIZE / PAGE_SIZE));
         }
         flush_tlb_range(vma, start, end);
 }
@@ -386,7 +386,7 @@ int hugetlb_prefault(struct address_space *mapping, struct vm_area_struct *vma)
                                 goto out;
                         }
                 }
-                add_mm_counter(mm, rss, HPAGE_SIZE / PAGE_SIZE);
+                add_mm_counter(mm, file_rss, HPAGE_SIZE / PAGE_SIZE);
                 set_huge_pte_at(mm, addr, pte, make_huge_pte(vma, page));
         }
 out:
diff --git a/mm/memory.c b/mm/memory.c
index 51eb38574830..59d42e50fa53 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -397,9 +397,10 @@ copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
                 pte = pte_mkclean(pte);
         pte = pte_mkold(pte);
         get_page(page);
-        inc_mm_counter(dst_mm, rss);
         if (PageAnon(page))
                 inc_mm_counter(dst_mm, anon_rss);
+        else
+                inc_mm_counter(dst_mm, file_rss);
         set_pte_at(dst_mm, addr, dst_pte, pte);
         page_dup_rmap(page);
 }
@@ -581,8 +582,8 @@ static void zap_pte_range(struct mmu_gather *tlb, pmd_t *pmd,
                                         set_page_dirty(page);
                                 if (pte_young(ptent))
                                         mark_page_accessed(page);
+                                dec_mm_counter(tlb->mm, file_rss);
                         }
-                        dec_mm_counter(tlb->mm, rss);
                         page_remove_rmap(page);
                         tlb_remove_page(tlb, page);
                         continue;
@@ -1290,13 +1291,15 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
         spin_lock(&mm->page_table_lock);
         page_table = pte_offset_map(pmd, address);
         if (likely(pte_same(*page_table, orig_pte))) {
-                if (PageAnon(old_page))
-                        dec_mm_counter(mm, anon_rss);
                 if (PageReserved(old_page))
-                        inc_mm_counter(mm, rss);
-                else
+                        inc_mm_counter(mm, anon_rss);
+                else {
                         page_remove_rmap(old_page);
-
+                        if (!PageAnon(old_page)) {
+                                inc_mm_counter(mm, anon_rss);
+                                dec_mm_counter(mm, file_rss);
+                        }
+                }
                 flush_cache_page(vma, address, pfn);
                 entry = mk_pte(new_page, vma->vm_page_prot);
                 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
@@ -1701,7 +1704,7 @@ static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
 
         /* The page isn't present yet, go ahead with the fault. */
 
-        inc_mm_counter(mm, rss);
+        inc_mm_counter(mm, anon_rss);
         pte = mk_pte(page, vma->vm_page_prot);
         if (write_access && can_share_swap_page(page)) {
                 pte = maybe_mkwrite(pte_mkdirty(pte), vma);
@@ -1774,7 +1777,7 @@ static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
                         page_cache_release(page);
                         goto unlock;
                 }
-                inc_mm_counter(mm, rss);
+                inc_mm_counter(mm, anon_rss);
                 entry = mk_pte(page, vma->vm_page_prot);
                 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
                 lru_cache_add_active(page);
@@ -1887,19 +1890,19 @@ retry:
          */
         /* Only go through if we didn't race with anybody else... */
         if (pte_none(*page_table)) {
-                if (!PageReserved(new_page))
-                        inc_mm_counter(mm, rss);
-
                 flush_icache_page(vma, new_page);
                 entry = mk_pte(new_page, vma->vm_page_prot);
                 if (write_access)
                         entry = maybe_mkwrite(pte_mkdirty(entry), vma);
                 set_pte_at(mm, address, page_table, entry);
                 if (anon) {
+                        inc_mm_counter(mm, anon_rss);
                         lru_cache_add_active(new_page);
                         page_add_anon_rmap(new_page, vma, address);
-                } else
+                } else if (!PageReserved(new_page)) {
+                        inc_mm_counter(mm, file_rss);
                         page_add_file_rmap(new_page);
+                }
         } else {
                 /* One of our sibling threads was faster, back out. */
                 page_cache_release(new_page);
@@ -2192,7 +2195,7 @@ EXPORT_SYMBOL(vmalloc_to_pfn);
 void update_mem_hiwater(struct task_struct *tsk)
 {
         if (tsk->mm) {
-                unsigned long rss = get_mm_counter(tsk->mm, rss);
+                unsigned long rss = get_mm_rss(tsk->mm);
 
                 if (tsk->mm->hiwater_rss < rss)
                         tsk->mm->hiwater_rss = rss;
diff --git a/mm/nommu.c b/mm/nommu.c
index 0ef241ae3763..599924886eb5 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1083,7 +1083,7 @@ void update_mem_hiwater(struct task_struct *tsk)
         unsigned long rss;
 
         if (likely(tsk->mm)) {
-                rss = get_mm_counter(tsk->mm, rss);
+                rss = get_mm_rss(tsk->mm);
                 if (tsk->mm->hiwater_rss < rss)
                         tsk->mm->hiwater_rss = rss;
                 if (tsk->mm->hiwater_vm < tsk->mm->total_vm)
diff --git a/mm/rmap.c b/mm/rmap.c
index 1fc559e09ca8..504757624cce 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -445,8 +445,6 @@ void page_add_anon_rmap(struct page *page,
 {
         BUG_ON(PageReserved(page));
 
-        inc_mm_counter(vma->vm_mm, anon_rss);
-
         if (atomic_inc_and_test(&page->_mapcount)) {
                 struct anon_vma *anon_vma = vma->anon_vma;
 
@@ -561,9 +559,9 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma)
                 set_pte_at(mm, address, pte, swp_entry_to_pte(entry));
                 BUG_ON(pte_file(*pte));
                 dec_mm_counter(mm, anon_rss);
-        }
+        } else
+                dec_mm_counter(mm, file_rss);
 
-        dec_mm_counter(mm, rss);
         page_remove_rmap(page);
         page_cache_release(page);
 
@@ -667,7 +665,7 @@ static void try_to_unmap_cluster(unsigned long cursor,
 
                 page_remove_rmap(page);
                 page_cache_release(page);
-                dec_mm_counter(mm, rss);
+                dec_mm_counter(mm, file_rss);
                 (*mapcount)--;
         }
 
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 05c851291241..296e0bbf7836 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -407,7 +407,7 @@ void free_swap_and_cache(swp_entry_t entry)
 static void unuse_pte(struct vm_area_struct *vma, pte_t *pte,
                 unsigned long addr, swp_entry_t entry, struct page *page)
 {
-        inc_mm_counter(vma->vm_mm, rss);
+        inc_mm_counter(vma->vm_mm, anon_rss);
         get_page(page);
         set_pte_at(vma->vm_mm, addr, pte,
                    pte_mkold(mk_pte(page, vma->vm_page_prot)));