[PATCH] zoned vm counters: remove NR_FILE_MAPPED from scan control structure

We can now access the number of pages in a mapped state in an inexpensive way
in shrink_active_list.  So drop the nr_mapped field from scan_control.

[akpm@osdl.org: bugfix]
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/mm/vmscan.c b/mm/vmscan.c
index d2caf74..08bc54e 100644 (file)
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -47,8 +47,6 @@ struct scan_control {
        /* Incremented by the number of inactive pages that were scanned */
        unsigned long nr_scanned;
 
-       unsigned long nr_mapped;        /* From page_state */
-
        /* This context's GFP mask */
        gfp_t gfp_mask;
 
@@ -744,7 +742,8 @@ static void shrink_active_list(unsigned long nr_pages, struct zone *zone,
                 * how much memory
                 * is mapped.
                 */
-               mapped_ratio = (sc->nr_mapped * 100) / vm_total_pages;
+               mapped_ratio = (global_page_state(NR_FILE_MAPPED) * 100) /
+                                       vm_total_pages;
 
                /*
                 * Now decide how much we really want to unmap some pages.  The
@@ -990,7 +989,6 @@ unsigned long try_to_free_pages(struct zone **zones, gfp_t gfp_mask)
        }
 
        for (priority = DEF_PRIORITY; priority >= 0; priority--) {
-               sc.nr_mapped = global_page_state(NR_FILE_MAPPED);
                sc.nr_scanned = 0;
                if (!priority)
                        disable_swap_token();
@@ -1075,8 +1073,6 @@ loop_again:
        total_scanned = 0;
        nr_reclaimed = 0;
        sc.may_writepage = !laptop_mode;
-       sc.nr_mapped = global_page_state(NR_FILE_MAPPED);
-
        inc_page_state(pageoutrun);
 
        for (i = 0; i < pgdat->nr_zones; i++) {
@@ -1407,9 +1403,7 @@ unsigned long shrink_all_memory(unsigned long nr_pages)
                for (prio = DEF_PRIORITY; prio >= 0; prio--) {
                        unsigned long nr_to_scan = nr_pages - ret;
 
-                       sc.nr_mapped = global_page_state(NR_FILE_MAPPED);
                        sc.nr_scanned = 0;
-
                        ret += shrink_all_zones(nr_to_scan, prio, pass, &sc);
                        if (ret >= nr_pages)
                                goto out;
@@ -1548,7 +1542,6 @@ static int __zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
        struct scan_control sc = {
                .may_writepage = !!(zone_reclaim_mode & RECLAIM_WRITE),
                .may_swap = !!(zone_reclaim_mode & RECLAIM_SWAP),
-               .nr_mapped = global_page_state(NR_FILE_MAPPED),
                .swap_cluster_max = max_t(unsigned long, nr_pages,
                                        SWAP_CLUSTER_MAX),
                .gfp_mask = gfp_mask,