[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>
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 27519df..afcaac6 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -254,6 +254,8 @@
#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 @@
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 */