[PATCH -mmotm 2/4] page_cgroup: introduce file cache flags

[Andrea Righi <arighi@develer.com>]

Introduce page_cgroup flags to keep track of file cache pages.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrea Righi <arighi@develer.com>
---
 include/linux/page_cgroup.h |   49 +++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 49 insertions(+), 0 deletions(-)

diff --git a/include/linux/page_cgroup.h b/include/linux/page_cgroup.h
index 30b0813..1b79ded 100644
--- a/include/linux/page_cgroup.h
+++ b/include/linux/page_cgroup.h
@@ -39,6 +39,12 @@ enum {
 	PCG_CACHE, /* charged as cache */
 	PCG_USED, /* this object is in use. */
 	PCG_ACCT_LRU, /* page has been accounted for */
+	PCG_MIGRATE_LOCK, /* used for mutual execution of account migration */
+	PCG_ACCT_FILE_MAPPED, /* page is accounted as file rss*/
+	PCG_ACCT_DIRTY, /* page is dirty */
+	PCG_ACCT_WRITEBACK, /* page is being written back to disk */
+	PCG_ACCT_WRITEBACK_TEMP, /* page is used as temporary buffer for FUSE */
+	PCG_ACCT_UNSTABLE_NFS, /* NFS page not yet committed to the server */
 };
 
 #define TESTPCGFLAG(uname, lname)			\
@@ -73,6 +79,27 @@ CLEARPCGFLAG(AcctLRU, ACCT_LRU)
 TESTPCGFLAG(AcctLRU, ACCT_LRU)
 TESTCLEARPCGFLAG(AcctLRU, ACCT_LRU)
 
+/* File cache and dirty memory flags */
+TESTPCGFLAG(FileMapped, ACCT_FILE_MAPPED)
+SETPCGFLAG(FileMapped, ACCT_FILE_MAPPED)
+CLEARPCGFLAG(FileMapped, ACCT_FILE_MAPPED)
+
+TESTPCGFLAG(Dirty, ACCT_DIRTY)
+SETPCGFLAG(Dirty, ACCT_DIRTY)
+CLEARPCGFLAG(Dirty, ACCT_DIRTY)
+
+TESTPCGFLAG(Writeback, ACCT_WRITEBACK)
+SETPCGFLAG(Writeback, ACCT_WRITEBACK)
+CLEARPCGFLAG(Writeback, ACCT_WRITEBACK)
+
+TESTPCGFLAG(WritebackTemp, ACCT_WRITEBACK_TEMP)
+SETPCGFLAG(WritebackTemp, ACCT_WRITEBACK_TEMP)
+CLEARPCGFLAG(WritebackTemp, ACCT_WRITEBACK_TEMP)
+
+TESTPCGFLAG(UnstableNFS, ACCT_UNSTABLE_NFS)
+SETPCGFLAG(UnstableNFS, ACCT_UNSTABLE_NFS)
+CLEARPCGFLAG(UnstableNFS, ACCT_UNSTABLE_NFS)
+
 static inline int page_cgroup_nid(struct page_cgroup *pc)
 {
 	return page_to_nid(pc->page);
@@ -83,6 +110,9 @@ static inline enum zone_type page_cgroup_zid(struct page_cgroup *pc)
 	return page_zonenum(pc->page);
 }
 
+/*
+ * lock_page_cgroup() should not be held under mapping->tree_lock
+ */
 static inline void lock_page_cgroup(struct page_cgroup *pc)
 {
 	bit_spin_lock(PCG_LOCK, &pc->flags);
@@ -93,6 +123,25 @@ static inline void unlock_page_cgroup(struct page_cgroup *pc)
 	bit_spin_unlock(PCG_LOCK, &pc->flags);
 }
 
+/*
+ * Lock order is
+ *     lock_page_cgroup()
+ *             lock_page_cgroup_migrate()
+ *
+ * This lock is not be lock for charge/uncharge but for account moving.
+ * i.e. overwrite pc->mem_cgroup. The lock owner should guarantee by itself
+ * the page is uncharged while we hold this.
+ */
+static inline void lock_page_cgroup_migrate(struct page_cgroup *pc)
+{
+	bit_spin_lock(PCG_MIGRATE_LOCK, &pc->flags);
+}
+
+static inline void unlock_page_cgroup_migrate(struct page_cgroup *pc)
+{
+	bit_spin_unlock(PCG_MIGRATE_LOCK, &pc->flags);
+}
+
 #else /* CONFIG_CGROUP_MEM_RES_CTLR */
 struct page_cgroup;
 
-- 
1.6.3.3

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