[PATCH 2/5] f2fs: use percpu_counter for page counters

[Jaegeuk Kim]

This patch substitutes percpu_counter for atomic_counter when counting
various types of pages.

Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
---
 fs/f2fs/debug.c |  1 +
 fs/f2fs/f2fs.h  | 12 +++++++-----
 fs/f2fs/super.c | 31 +++++++++++++++++++++++++++----
 3 files changed, 35 insertions(+), 9 deletions(-)

diff --git a/fs/f2fs/debug.c b/fs/f2fs/debug.c
index 37615b2..2210c7c 100644
--- a/fs/f2fs/debug.c
+++ b/fs/f2fs/debug.c
@@ -144,6 +144,7 @@ static void update_mem_info(struct f2fs_sb_info *sbi)
 	si->base_mem = sizeof(struct f2fs_sb_info) + sbi->sb->s_blocksize;
 	si->base_mem += 2 * sizeof(struct f2fs_inode_info);
 	si->base_mem += sizeof(*sbi->ckpt);
+	si->base_mem += sizeof(struct percpu_counter) * NR_COUNT_TYPE;
 
 	/* build sm */
 	si->base_mem += sizeof(struct f2fs_sm_info);
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 24f8170..2851078 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -833,7 +833,9 @@ struct f2fs_sb_info {
 	block_t discard_blks;			/* discard command candidats */
 	block_t last_valid_block_count;		/* for recovery */
 	u32 s_next_generation;			/* for NFS support */
-	atomic_t nr_pages[NR_COUNT_TYPE];	/* # of pages, see count_type */
+
+	/* # of pages, see count_type */
+	struct percpu_counter nr_pages[NR_COUNT_TYPE];
 
 	struct f2fs_mount_info mount_opt;	/* mount options */
 
@@ -1178,7 +1180,7 @@ static inline void dec_valid_block_count(struct f2fs_sb_info *sbi,
 
 static inline void inc_page_count(struct f2fs_sb_info *sbi, int count_type)
 {
-	atomic_inc(&sbi->nr_pages[count_type]);
+	percpu_counter_inc(&sbi->nr_pages[count_type]);
 	set_sbi_flag(sbi, SBI_IS_DIRTY);
 }
 
@@ -1191,7 +1193,7 @@ static inline void inode_inc_dirty_pages(struct inode *inode)
 
 static inline void dec_page_count(struct f2fs_sb_info *sbi, int count_type)
 {
-	atomic_dec(&sbi->nr_pages[count_type]);
+	percpu_counter_dec(&sbi->nr_pages[count_type]);
 }
 
 static inline void inode_dec_dirty_pages(struct inode *inode)
@@ -1205,9 +1207,9 @@ static inline void inode_dec_dirty_pages(struct inode *inode)
 				F2FS_DIRTY_DENTS : F2FS_DIRTY_DATA);
 }
 
-static inline int get_pages(struct f2fs_sb_info *sbi, int count_type)
+static inline s64 get_pages(struct f2fs_sb_info *sbi, int count_type)
 {
-	return atomic_read(&sbi->nr_pages[count_type]);
+	return percpu_counter_sum_positive(&sbi->nr_pages[count_type]);
 }
 
 static inline int get_dirty_pages(struct inode *inode)
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 9df6d72..b3030ed 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -606,6 +606,14 @@ static void f2fs_destroy_inode(struct inode *inode)
 	call_rcu(&inode->i_rcu, f2fs_i_callback);
 }
 
+static void destroy_percpu_info(struct f2fs_sb_info *sbi)
+{
+	int i;
+
+	for (i = 0; i < NR_COUNT_TYPE; i++)
+		percpu_counter_destroy(&sbi->nr_pages[i]);
+}
+
 static void f2fs_put_super(struct super_block *sb)
 {
 	struct f2fs_sb_info *sbi = F2FS_SB(sb);
@@ -667,6 +675,8 @@ static void f2fs_put_super(struct super_block *sb)
 	if (sbi->s_chksum_driver)
 		crypto_free_shash(sbi->s_chksum_driver);
 	kfree(sbi->raw_super);
+
+	destroy_percpu_info(sbi);
 	kfree(sbi);
 }
 
@@ -1325,7 +1335,6 @@ int sanity_check_ckpt(struct f2fs_sb_info *sbi)
 static void init_sb_info(struct f2fs_sb_info *sbi)
 {
 	struct f2fs_super_block *raw_super = sbi->raw_super;
-	int i;
 
 	sbi->log_sectors_per_block =
 		le32_to_cpu(raw_super->log_sectors_per_block);
@@ -1345,9 +1354,6 @@ static void init_sb_info(struct f2fs_sb_info *sbi)
 	sbi->cur_victim_sec = NULL_SECNO;
 	sbi->max_victim_search = DEF_MAX_VICTIM_SEARCH;
 
-	for (i = 0; i < NR_COUNT_TYPE; i++)
-		atomic_set(&sbi->nr_pages[i], 0);
-
 	sbi->dir_level = DEF_DIR_LEVEL;
 	sbi->interval_time[CP_TIME] = DEF_CP_INTERVAL;
 	sbi->interval_time[REQ_TIME] = DEF_IDLE_INTERVAL;
@@ -1363,6 +1369,18 @@ static void init_sb_info(struct f2fs_sb_info *sbi)
 #endif
 }
 
+static int init_percpu_info(struct f2fs_sb_info *sbi)
+{
+	int i, err;
+
+	for (i = 0; i < NR_COUNT_TYPE; i++) {
+		err = percpu_counter_init(&sbi->nr_pages[i], 0, GFP_KERNEL);
+		if (err)
+			return err;
+	}
+	return 0;
+}
+
 /*
  * Read f2fs raw super block.
  * Because we have two copies of super block, so read both of them
@@ -1553,6 +1571,10 @@ try_onemore:
 	init_waitqueue_head(&sbi->cp_wait);
 	init_sb_info(sbi);
 
+	err = init_percpu_info(sbi);
+	if (err)
+		goto free_options;
+
 	/* get an inode for meta space */
 	sbi->meta_inode = f2fs_iget(sb, F2FS_META_INO(sbi));
 	if (IS_ERR(sbi->meta_inode)) {
@@ -1755,6 +1777,7 @@ free_meta_inode:
 	make_bad_inode(sbi->meta_inode);
 	iput(sbi->meta_inode);
 free_options:
+	destroy_percpu_info(sbi);
 	kfree(options);
 free_sb_buf:
 	kfree(raw_super);
-- 
2.6.3