[RFC][PATCH] vmscan: don't export nr_saved_scan in /proc/zoneinfo

[Wu Fengguang <fengguang.wu@intel.com>]

The lru->nr_saved_scan's are not meaningful counters for even kernel
developers.  They typically are smaller than 32 and are always 0 for
large lists. So remove them from /proc/zoneinfo.

Hopefully this interface change won't break too many scripts.
/proc/zoneinfo is too unstructured to be script friendly, and I wonder
the affected scripts - if there are any - are still bleeding since the
not long ago commit "vmscan: split LRU lists into anon & file sets",
which also touched the "scanned" line :)

If we are to re-export accumulated vmscan counts in the future, they
can go to new lines in /proc/zoneinfo instead of the current form, or
to /sys/devices/system/node/node0/meminfo?

CC: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
---
 mm/vmstat.c |    6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

--- mm.orig/mm/vmstat.c
+++ mm/mm/vmstat.c
@@ -721,7 +721,7 @@ static void zoneinfo_show_print(struct s
 		   "\n        min      %lu"
 		   "\n        low      %lu"
 		   "\n        high     %lu"
-		   "\n        scanned  %lu (aa: %lu ia: %lu af: %lu if: %lu)"
+		   "\n        scanned  %lu"
 		   "\n        spanned  %lu"
 		   "\n        present  %lu",
 		   zone_page_state(zone, NR_FREE_PAGES),
@@ -729,10 +729,6 @@ static void zoneinfo_show_print(struct s
 		   zone->pages_low,
 		   zone->pages_high,
 		   zone->pages_scanned,
-		   zone->lru[LRU_ACTIVE_ANON].nr_saved_scan,
-		   zone->lru[LRU_INACTIVE_ANON].nr_saved_scan,
-		   zone->lru[LRU_ACTIVE_FILE].nr_saved_scan,
-		   zone->lru[LRU_INACTIVE_FILE].nr_saved_scan,
 		   zone->spanned_pages,
 		   zone->present_pages);