[PATCH 5/5] add shmem vmstat

ChangeLog
  Since v1
   - Fixed misaccounting bug on page migration

========================
Subject: [PATCH] add shmem vmstat

Recently, We faced several OOM problem by plenty GEM cache. and generally,
plenty Shmem/Tmpfs potentially makes memory shortage problem.

We often use following calculation to know shmem pages,
  shmem = NR_ACTIVE_ANON + NR_INACTIVE_ANON - NR_ANON_PAGES
but it is wrong expression. it doesn't consider isolated page and
mlocked page.

Then, This patch make explicit Shmem/Tmpfs vm-stat accounting.


Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@...>
---
 drivers/base/node.c    |    2 ++
 fs/proc/meminfo.c      |    2 ++
 include/linux/mmzone.h |    1 +
 mm/filemap.c           |    4 ++++
 mm/migrate.c           |    4 ++++
 mm/page_alloc.c        |    5 ++++-
 mm/vmstat.c            |    1 +
 7 files changed, 18 insertions(+), 1 deletion(-)

Index: b/drivers/base/node.c
===================================================================
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -87,6 +87,7 @@ static ssize_t node_read_meminfo(struct
        "Node %d FilePages:      %8lu kB\n"
        "Node %d Mapped:         %8lu kB\n"
        "Node %d AnonPages:      %8lu kB\n"
+       "Node %d Shmem:          %8lu kB\n"
        "Node %d KernelStack:    %8lu kB\n"
        "Node %d PageTables:     %8lu kB\n"
        "Node %d NFS_Unstable:   %8lu kB\n"
@@ -121,6 +122,7 @@ static ssize_t node_read_meminfo(struct
        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(node_page_state(nid, NR_SHMEM)),
        nid, node_page_state(nid, NR_KERNEL_STACK) *
  THREAD_SIZE / 1024,
        nid, K(node_page_state(nid, NR_PAGETABLE)),
Index: b/fs/proc/meminfo.c
===================================================================
--- a/fs/proc/meminfo.c
+++ b/fs/proc/meminfo.c
@@ -83,6 +83,7 @@ static int meminfo_proc_show(struct seq_
  "Writeback:      %8lu kB\n"
  "AnonPages:      %8lu kB\n"
  "Mapped:         %8lu kB\n"
+ "Shmem:          %8lu kB\n"
  "Slab:           %8lu kB\n"
  "SReclaimable:   %8lu kB\n"
  "SUnreclaim:     %8lu kB\n"
@@ -129,6 +130,7 @@ static int meminfo_proc_show(struct seq_
  K(global_page_state(NR_WRITEBACK)),
  K(global_page_state(NR_ANON_PAGES)),
  K(global_page_state(NR_FILE_MAPPED)),
+ K(global_page_state(NR_SHMEM)),
  K(global_page_state(NR_SLAB_RECLAIMABLE) +
  global_page_state(NR_SLAB_UNRECLAIMABLE)),
  K(global_page_state(NR_SLAB_RECLAIMABLE)),
Index: b/include/linux/mmzone.h
===================================================================
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -102,6 +102,7 @@ enum zone_stat_item {
  NR_WRITEBACK_TEMP, /* Writeback using temporary buffers */
  NR_ISOLATED_ANON, /* Temporary isolated pages from anon lru */
  NR_ISOLATED_FILE, /* Temporary isolated pages from file lru */
+ NR_SHMEM, /* shmem pages (included tmpfs/GEM pages) */
 #ifdef CONFIG_NUMA
  NUMA_HIT, /* allocated in intended node */
  NUMA_MISS, /* allocated in non intended node */
Index: b/mm/filemap.c
===================================================================
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -120,6 +120,8 @@ void __remove_from_page_cache(struct pag
  page->mapping = NULL;
  mapping->nrpages--;
  __dec_zone_page_state(page, NR_FILE_PAGES);
+ if (PageSwapBacked(page))
+ __dec_zone_page_state(page, NR_SHMEM);
  BUG_ON(page_mapped(page));
 
  /*
@@ -476,6 +478,8 @@ int add_to_page_cache_locked(struct page
  if (likely(!error)) {
  mapping->nrpages++;
  __inc_zone_page_state(page, NR_FILE_PAGES);
+ if (PageSwapBacked(page))
+ __inc_zone_page_state(page, NR_SHMEM);
  spin_unlock_irq(&mapping->tree_lock);
  } else {
  page->mapping = NULL;
Index: b/mm/vmstat.c
===================================================================
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -646,6 +646,7 @@ static const char * const vmstat_text[]
  "nr_writeback_temp",
  "nr_isolated_anon",
  "nr_isolated_file",
+ "nr_shmem",
 #ifdef CONFIG_NUMA
  "numa_hit",
  "numa_miss",
Index: b/mm/page_alloc.c
===================================================================
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2120,7 +2120,7 @@ void show_free_areas(void)
  " unevictable:%lu\n"
  " dirty:%lu writeback:%lu unstable:%lu buffer:%lu\n"
  " free:%lu slab_reclaimable:%lu slab_unreclaimable:%lu\n"
- " mapped:%lu pagetables:%lu bounce:%lu\n",
+ " mapped:%lu shmem:%lu pagetables:%lu bounce:%lu\n",
  global_page_state(NR_ACTIVE_ANON),
  global_page_state(NR_INACTIVE_ANON),
  global_page_state(NR_ISOLATED_ANON),
@@ -2136,6 +2136,7 @@ void show_free_areas(void)
  global_page_state(NR_SLAB_RECLAIMABLE),
  global_page_state(NR_SLAB_UNRECLAIMABLE),
  global_page_state(NR_FILE_MAPPED),
+ global_page_state(NR_SHMEM),
  global_page_state(NR_PAGETABLE),
  global_page_state(NR_BOUNCE));
 
@@ -2160,6 +2161,7 @@ void show_free_areas(void)
  " dirty:%lukB"
  " writeback:%lukB"
  " mapped:%lukB"
+ " shmem:%lukB"
  " slab_reclaimable:%lukB"
  " slab_unreclaimable:%lukB"
  " kernel_stack:%lukB"
@@ -2187,6 +2189,7 @@ void show_free_areas(void)
  K(zone_page_state(zone, NR_FILE_DIRTY)),
  K(zone_page_state(zone, NR_WRITEBACK)),
  K(zone_page_state(zone, NR_FILE_MAPPED)),
+ K(zone_page_state(zone, NR_SHMEM)),
  K(zone_page_state(zone, NR_SLAB_RECLAIMABLE)),
  K(zone_page_state(zone, NR_SLAB_UNRECLAIMABLE)),
  zone_page_state(zone, NR_KERNEL_STACK) *
Index: b/mm/migrate.c
===================================================================
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -312,7 +312,11 @@ static int migrate_page_move_mapping(str
  */
  __dec_zone_page_state(page, NR_FILE_PAGES);
  __inc_zone_page_state(newpage, NR_FILE_PAGES);
+ if (PageSwapBacked(page)) {
+ __dec_zone_page_state(page, NR_SHMEM);
+ __inc_zone_page_state(newpage, NR_SHMEM);
 
+ }
  spin_unlock_irq(&mapping->tree_lock);
 
  return 0;


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