From: Christoph Lameter The current NR_FILE_MAPPED is used by zone reclaim and the dirty load calculation as the number of mapped pagecache pages. However, that is not true. NR_FILE_MAPPED includes the mapped anonymous pages. This patch separates those and therefore allows an accurate tracking of the anonymous pages per zone. It then becomes possible to determine the number of unmapped pages per zone and we can avoid scanning for unmapped pages if there are none. Also it may now be possible to determine the mapped/unmapped ratio in get_dirty_limit. Isnt the number of anonymous pages irrelevant in that calculation? Note that this will change the meaning of the number of mapped pages reported in /proc/vmstat /proc/meminfo and in the per node statistics. This may affect user space tools that monitor these counters! NR_FILE_MAPPED works like NR_FILE_DIRTY. It is only valid for pagecache pages. Signed-off-by: Christoph Lameter Signed-off-by: Andrew Morton --- drivers/base/node.c | 2 ++ fs/proc/proc_misc.c | 2 ++ include/linux/mmzone.h | 3 ++- mm/page-writeback.c | 3 ++- mm/rmap.c | 5 +++-- mm/vmscan.c | 3 ++- mm/vmstat.c | 1 + 7 files changed, 14 insertions(+), 5 deletions(-) diff -puN drivers/base/node.c~zoned-vm-counters-split-nr_anon_pages-off-from-nr_file_mapped drivers/base/node.c --- a/drivers/base/node.c~zoned-vm-counters-split-nr_anon_pages-off-from-nr_file_mapped +++ a/drivers/base/node.c @@ -71,6 +71,7 @@ static ssize_t node_read_meminfo(struct "Node %d Writeback: %8lu kB\n" "Node %d FilePages: %8lu kB\n" "Node %d Mapped: %8lu kB\n" + "Node %d AnonPages: %8lu kB\n" "Node %d Slab: %8lu kB\n", nid, K(i.totalram), nid, K(i.freeram), @@ -85,6 +86,7 @@ static ssize_t node_read_meminfo(struct nid, K(ps.nr_writeback), nid, K(node_page_state(nid, NR_FILE_PAGES)), nid, K(node_page_state(nid, NR_FILE_MAPPED)), + nid, K(node_page_state(nid, NR_ANON_PAGES)), nid, K(ps.nr_slab)); n += hugetlb_report_node_meminfo(nid, buf + n); return n; diff -puN fs/proc/proc_misc.c~zoned-vm-counters-split-nr_anon_pages-off-from-nr_file_mapped fs/proc/proc_misc.c --- a/fs/proc/proc_misc.c~zoned-vm-counters-split-nr_anon_pages-off-from-nr_file_mapped +++ a/fs/proc/proc_misc.c @@ -168,6 +168,7 @@ static int meminfo_read_proc(char *page, "SwapFree: %8lu kB\n" "Dirty: %8lu kB\n" "Writeback: %8lu kB\n" + "AnonPages: %8lu kB\n" "Mapped: %8lu kB\n" "Slab: %8lu kB\n" "CommitLimit: %8lu kB\n" @@ -191,6 +192,7 @@ static int meminfo_read_proc(char *page, K(i.freeswap), K(ps.nr_dirty), K(ps.nr_writeback), + K(global_page_state(NR_ANON_PAGES)), K(global_page_state(NR_FILE_MAPPED)), K(ps.nr_slab), K(allowed), diff -puN include/linux/mmzone.h~zoned-vm-counters-split-nr_anon_pages-off-from-nr_file_mapped include/linux/mmzone.h --- a/include/linux/mmzone.h~zoned-vm-counters-split-nr_anon_pages-off-from-nr_file_mapped +++ a/include/linux/mmzone.h @@ -47,7 +47,8 @@ struct zone_padding { #endif enum zone_stat_item { - NR_FILE_MAPPED, /* mapped into pagetables. + NR_ANON_PAGES, /* Mapped anonymous pages */ + NR_FILE_MAPPED, /* pagecache pages mapped into pagetables. only modified from process context */ NR_FILE_PAGES, NR_VM_ZONE_STAT_ITEMS }; diff -puN mm/page-writeback.c~zoned-vm-counters-split-nr_anon_pages-off-from-nr_file_mapped mm/page-writeback.c --- a/mm/page-writeback.c~zoned-vm-counters-split-nr_anon_pages-off-from-nr_file_mapped +++ a/mm/page-writeback.c @@ -112,7 +112,8 @@ static void get_writeback_state(struct w { wbs->nr_dirty = read_page_state(nr_dirty); wbs->nr_unstable = read_page_state(nr_unstable); - wbs->nr_mapped = global_page_state(NR_FILE_MAPPED); + wbs->nr_mapped = global_page_state(NR_FILE_MAPPED) + + global_page_state(NR_ANON_PAGES); wbs->nr_writeback = read_page_state(nr_writeback); } diff -puN mm/rmap.c~zoned-vm-counters-split-nr_anon_pages-off-from-nr_file_mapped mm/rmap.c --- a/mm/rmap.c~zoned-vm-counters-split-nr_anon_pages-off-from-nr_file_mapped +++ a/mm/rmap.c @@ -523,7 +523,7 @@ static void __page_set_anon_rmap(struct * nr_mapped state can be updated without turning off * interrupts because it is not modified via interrupt. */ - __inc_zone_page_state(page, NR_FILE_MAPPED); + __inc_zone_page_state(page, NR_ANON_PAGES); } /** @@ -599,7 +599,8 @@ void page_remove_rmap(struct page *page) */ if (page_test_and_clear_dirty(page)) set_page_dirty(page); - __dec_zone_page_state(page, NR_FILE_MAPPED); + __dec_zone_page_state(page, + PageAnon(page) ? NR_ANON_PAGES : NR_FILE_MAPPED); } } diff -puN mm/vmscan.c~zoned-vm-counters-split-nr_anon_pages-off-from-nr_file_mapped mm/vmscan.c --- a/mm/vmscan.c~zoned-vm-counters-split-nr_anon_pages-off-from-nr_file_mapped +++ a/mm/vmscan.c @@ -742,7 +742,8 @@ static void shrink_active_list(unsigned * how much memory * is mapped. */ - mapped_ratio = (global_page_state(NR_FILE_MAPPED) * 100) / + mapped_ratio = ((global_page_state(NR_FILE_MAPPED) + + global_page_state(NR_ANON_PAGES)) * 100) / vm_total_pages; /* diff -puN mm/vmstat.c~zoned-vm-counters-split-nr_anon_pages-off-from-nr_file_mapped mm/vmstat.c --- a/mm/vmstat.c~zoned-vm-counters-split-nr_anon_pages-off-from-nr_file_mapped +++ a/mm/vmstat.c @@ -457,6 +457,7 @@ struct seq_operations fragmentation_op = static char *vmstat_text[] = { /* Zoned VM counters */ + "nr_anon_pages", "nr_mapped", "nr_file_pages", _