vmscan: split LRU lists into anon & file sets

Split the LRU lists in two, one set for pages that are backed by real file
systems ("file") and one for pages that are backed by memory and swap
("anon").  The latter includes tmpfs.

The advantage of doing this is that the VM will not have to scan over lots
of anonymous pages (which we generally do not want to swap out), just to
find the page cache pages that it should evict.

This patch has the infrastructure and a basic policy to balance how much
we scan the anon lists and how much we scan the file lists.  The big
policy changes are in separate patches.

[[email protected]: collect lru meminfo statistics from correct offset]
[[email protected]: prevent incorrect oom under split_lru]
[[email protected]: fix pagevec_move_tail() doesn't treat unevictable page]
[[email protected]: memcg swapbacked pages active]
[[email protected]: splitlru: BDI_CAP_SWAP_BACKED]
[[email protected]: fix /proc/vmstat units]
[[email protected]: memcg: fix handling of shmem migration]
[[email protected]: adjust Quicklists field of /proc/meminfo]
[[email protected]: fix style issue of get_scan_ratio()]
Signed-off-by: Rik van Riel <[email protected]>
Signed-off-by: Lee Schermerhorn <[email protected]>
Signed-off-by: KOSAKI Motohiro <[email protected]>
Signed-off-by: Hugh Dickins <[email protected]>
Signed-off-by: Daisuke Nishimura <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

1 files changed, 13 insertions, 0 deletions

diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index 0a24d5550eb3..bee52abb8a4d 100644
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -175,6 +175,8 @@ int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio);
  * BDI_CAP_READ_MAP:       Can be mapped for reading
  * BDI_CAP_WRITE_MAP:      Can be mapped for writing
  * BDI_CAP_EXEC_MAP:       Can be mapped for execution
+ *
+ * BDI_CAP_SWAP_BACKED:    Count shmem/tmpfs objects as swap-backed.
  */
 #define BDI_CAP_NO_ACCT_DIRTY	0x00000001
 #define BDI_CAP_NO_WRITEBACK	0x00000002
@@ -184,6 +186,7 @@ int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio);
 #define BDI_CAP_WRITE_MAP	0x00000020
 #define BDI_CAP_EXEC_MAP	0x00000040
 #define BDI_CAP_NO_ACCT_WB	0x00000080
+#define BDI_CAP_SWAP_BACKED	0x00000100
 
 #define BDI_CAP_VMFLAGS \
 	(BDI_CAP_READ_MAP | BDI_CAP_WRITE_MAP | BDI_CAP_EXEC_MAP)
@@ -248,6 +251,11 @@ static inline bool bdi_cap_account_writeback(struct backing_dev_info *bdi)
 				      BDI_CAP_NO_WRITEBACK));
 }
 
+static inline bool bdi_cap_swap_backed(struct backing_dev_info *bdi)
+{
+	return bdi->capabilities & BDI_CAP_SWAP_BACKED;
+}
+
 static inline bool mapping_cap_writeback_dirty(struct address_space *mapping)
 {
 	return bdi_cap_writeback_dirty(mapping->backing_dev_info);
@@ -258,4 +266,9 @@ static inline bool mapping_cap_account_dirty(struct address_space *mapping)
 	return bdi_cap_account_dirty(mapping->backing_dev_info);
 }
 
+static inline bool mapping_cap_swap_backed(struct address_space *mapping)
+{
+	return bdi_cap_swap_backed(mapping->backing_dev_info);
+}
+
 #endif		/* _LINUX_BACKING_DEV_H */