[PATCH] zoned vm counters: convert nr_mapped to per zone counter

nr_mapped is important because it allows a determination of how many pages of
a zone are not mapped, which would allow a more efficient means of determining
when we need to reclaim memory in a zone.

We take the nr_mapped field out of the page state structure and define a new
per zone counter named NR_FILE_MAPPED (the anonymous pages will be split off
from NR_MAPPED in the next patch).

We replace the use of nr_mapped in various kernel locations.  This avoids the
looping over all processors in try_to_free_pages(), writeback, reclaim (swap +
zone reclaim).

[akpm@osdl.org: bugfix]
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/arch/i386/mm/pgtable.c b/arch/i386/mm/pgtable.c
index 2889567..f85f1a4 100644 (file)
--- a/arch/i386/mm/pgtable.c
+++ b/arch/i386/mm/pgtable.c
@@ -61,7 +61,7 @@ void show_mem(void)
        get_page_state(&ps);
        printk(KERN_INFO "%lu pages dirty\n", ps.nr_dirty);
        printk(KERN_INFO "%lu pages writeback\n", ps.nr_writeback);
-       printk(KERN_INFO "%lu pages mapped\n", ps.nr_mapped);
+       printk(KERN_INFO "%lu pages mapped\n", global_page_state(NR_FILE_MAPPED));
        printk(KERN_INFO "%lu pages slab\n", ps.nr_slab);
        printk(KERN_INFO "%lu pages pagetables\n", ps.nr_page_table_pages);
 }

diff --git a/drivers/base/node.c b/drivers/base/node.c
index eae2bdc..8b12323 100644 (file)
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -54,8 +54,6 @@ static ssize_t node_read_meminfo(struct sys_device * dev, char * buf)
                ps.nr_dirty = 0;
        if ((long)ps.nr_writeback < 0)
                ps.nr_writeback = 0;
-       if ((long)ps.nr_mapped < 0)
-               ps.nr_mapped = 0;
        if ((long)ps.nr_slab < 0)
                ps.nr_slab = 0;
 
@@ -84,7 +82,7 @@ static ssize_t node_read_meminfo(struct sys_device * dev, char * buf)
                       nid, K(i.freeram - i.freehigh),
                       nid, K(ps.nr_dirty),
                       nid, K(ps.nr_writeback),
-                      nid, K(ps.nr_mapped),
+                      nid, K(node_page_state(nid, NR_FILE_MAPPED)),
                       nid, K(ps.nr_slab));
        n += hugetlb_report_node_meminfo(nid, buf + n);
        return n;

diff --git a/fs/proc/proc_misc.c b/fs/proc/proc_misc.c
index 5c10ea1..bc7d9ab 100644 (file)
--- a/fs/proc/proc_misc.c
+++ b/fs/proc/proc_misc.c
@@ -190,7 +190,7 @@ static int meminfo_read_proc(char *page, char **start, off_t off,
                K(i.freeswap),
                K(ps.nr_dirty),
                K(ps.nr_writeback),
-               K(ps.nr_mapped),
+               K(global_page_state(NR_FILE_MAPPED)),
                K(ps.nr_slab),
                K(allowed),
                K(committed),

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 543f9e4..eb42c12 100644 (file)
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -47,6 +47,9 @@ struct zone_padding {
 #endif
 
 enum zone_stat_item {
+       NR_FILE_MAPPED, /* mapped into pagetables.
+                          only modified from process context */
+
        NR_VM_ZONE_STAT_ITEMS };
 
 struct per_cpu_pages {

diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h
index 3fd5c11..8ab8229 100644 (file)
--- a/include/linux/vmstat.h
+++ b/include/linux/vmstat.h
@@ -26,8 +26,6 @@ struct page_state {
        unsigned long nr_writeback;     /* Pages under writeback */
        unsigned long nr_unstable;      /* NFS unstable pages */
        unsigned long nr_page_table_pages;/* Pages used for pagetables */
-       unsigned long nr_mapped;        /* mapped into pagetables.
-                                        * only modified from process context */
        unsigned long nr_slab;          /* In slab */
 #define GET_PAGE_STATE_LAST nr_slab
 

diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 4ec7026..60c7244 100644 (file)
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -111,7 +111,7 @@ static void get_writeback_state(struct writeback_state *wbs)
 {
        wbs->nr_dirty = read_page_state(nr_dirty);
        wbs->nr_unstable = read_page_state(nr_unstable);
-       wbs->nr_mapped = read_page_state(nr_mapped);
+       wbs->nr_mapped = global_page_state(NR_FILE_MAPPED);
        wbs->nr_writeback = read_page_state(nr_writeback);
 }
 

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 3a877fe..04dd2b0 100644 (file)
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1319,7 +1319,7 @@ void show_free_areas(void)
                ps.nr_unstable,
                nr_free_pages(),
                ps.nr_slab,
-               ps.nr_mapped,
+               global_page_state(NR_FILE_MAPPED),
                ps.nr_page_table_pages);
 
        for_each_zone(zone) {

diff --git a/mm/rmap.c b/mm/rmap.c
index e76909e..af5e980 100644 (file)
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -455,7 +455,7 @@ static void __page_set_anon_rmap(struct page *page,
         * nr_mapped state can be updated without turning off
         * interrupts because it is not modified via interrupt.
         */
-       __inc_page_state(nr_mapped);
+       __inc_zone_page_state(page, NR_FILE_MAPPED);
 }
 
 /**
@@ -499,7 +499,7 @@ void page_add_new_anon_rmap(struct page *page,
 void page_add_file_rmap(struct page *page)
 {
        if (atomic_inc_and_test(&page->_mapcount))
-               __inc_page_state(nr_mapped);
+               __inc_zone_page_state(page, NR_FILE_MAPPED);
 }
 
 /**
@@ -531,7 +531,7 @@ void page_remove_rmap(struct page *page)
                 */
                if (page_test_and_clear_dirty(page))
                        set_page_dirty(page);
-               __dec_page_state(nr_mapped);
+               __dec_zone_page_state(page, NR_FILE_MAPPED);
        }
 }
 

diff --git a/mm/vmscan.c b/mm/vmscan.c
index eeacb0d..d2caf74 100644 (file)
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -990,7 +990,7 @@ unsigned long try_to_free_pages(struct zone **zones, gfp_t gfp_mask)
        }
 
        for (priority = DEF_PRIORITY; priority >= 0; priority--) {
-               sc.nr_mapped = read_page_state(nr_mapped);
+               sc.nr_mapped = global_page_state(NR_FILE_MAPPED);
                sc.nr_scanned = 0;
                if (!priority)
                        disable_swap_token();
@@ -1075,7 +1075,7 @@ loop_again:
        total_scanned = 0;
        nr_reclaimed = 0;
        sc.may_writepage = !laptop_mode;
-       sc.nr_mapped = read_page_state(nr_mapped);
+       sc.nr_mapped = global_page_state(NR_FILE_MAPPED);
 
        inc_page_state(pageoutrun);
 
@@ -1407,7 +1407,7 @@ 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 = read_page_state(nr_mapped);
+                       sc.nr_mapped = global_page_state(NR_FILE_MAPPED);
                        sc.nr_scanned = 0;
 
                        ret += shrink_all_zones(nr_to_scan, prio, pass, &sc);
@@ -1548,7 +1548,7 @@ 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 = read_page_state(nr_mapped),
+               .nr_mapped = global_page_state(NR_FILE_MAPPED),
                .swap_cluster_max = max_t(unsigned long, nr_pages,
                                        SWAP_CLUSTER_MAX),
                .gfp_mask = gfp_mask,

diff --git a/mm/vmstat.c b/mm/vmstat.c
index 210f9bb..4800091 100644 (file)
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -401,13 +401,13 @@ struct seq_operations fragmentation_op = {
 
 static char *vmstat_text[] = {
        /* Zoned VM counters */
+       "nr_mapped",
 
        /* Page state */
        "nr_dirty",
        "nr_writeback",
        "nr_unstable",
        "nr_page_table_pages",
-       "nr_mapped",
        "nr_slab",
 
        "pgpgin",