linux-kernel - [PATCH 4.8 53/85] Revert "f2fs: use percpu_counter for # of dirty pages in inode"

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Date:   Wed,  4 Jan 2017 21:47:38 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Jaegeuk Kim <jaegeuk@...nel.org>
Subject: [PATCH 4.8 53/85] Revert "f2fs: use percpu_counter for # of dirty pages in inode"

4.8-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jaegeuk Kim <jaegeuk@...nel.org>

commit 204706c7accfabb67b97eef9f9a28361b6201199 upstream.

This reverts commit 1beba1b3a953107c3ff5448ab4e4297db4619c76.

The perpcu_counter doesn't provide atomicity in single core and consume more
DRAM. That incurs fs_mark test failure due to ENOMEM.

Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 fs/f2fs/f2fs.h  |   10 +++++-----
 fs/f2fs/file.c  |    2 +-
 fs/f2fs/super.c |    7 +------
 3 files changed, 7 insertions(+), 12 deletions(-)

--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -451,7 +451,7 @@ struct f2fs_inode_info {
 	/* Use below internally in f2fs*/
 	unsigned long flags;		/* use to pass per-file flags */
 	struct rw_semaphore i_sem;	/* protect fi info */
-	struct percpu_counter dirty_pages;	/* # of dirty pages */
+	atomic_t dirty_pages;		/* # of dirty pages */
 	f2fs_hash_t chash;		/* hash value of given file name */
 	unsigned int clevel;		/* maximum level of given file name */
 	nid_t i_xattr_nid;		/* node id that contains xattrs */
@@ -1198,7 +1198,7 @@ static inline void inc_page_count(struct
 
 static inline void inode_inc_dirty_pages(struct inode *inode)
 {
-	percpu_counter_inc(&F2FS_I(inode)->dirty_pages);
+	atomic_inc(&F2FS_I(inode)->dirty_pages);
 	inc_page_count(F2FS_I_SB(inode), S_ISDIR(inode->i_mode) ?
 				F2FS_DIRTY_DENTS : F2FS_DIRTY_DATA);
 }
@@ -1214,7 +1214,7 @@ static inline void inode_dec_dirty_pages
 			!S_ISLNK(inode->i_mode))
 		return;
 
-	percpu_counter_dec(&F2FS_I(inode)->dirty_pages);
+	atomic_dec(&F2FS_I(inode)->dirty_pages);
 	dec_page_count(F2FS_I_SB(inode), S_ISDIR(inode->i_mode) ?
 				F2FS_DIRTY_DENTS : F2FS_DIRTY_DATA);
 }
@@ -1224,9 +1224,9 @@ static inline s64 get_pages(struct f2fs_
 	return percpu_counter_sum_positive(&sbi->nr_pages[count_type]);
 }
 
-static inline s64 get_dirty_pages(struct inode *inode)
+static inline int get_dirty_pages(struct inode *inode)
 {
-	return percpu_counter_sum_positive(&F2FS_I(inode)->dirty_pages);
+	return atomic_read(&F2FS_I(inode)->dirty_pages);
 }
 
 static inline int get_blocktype_secs(struct f2fs_sb_info *sbi, int block_type)
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -1529,7 +1529,7 @@ static int f2fs_ioc_start_atomic_write(s
 		goto out;
 
 	f2fs_msg(F2FS_I_SB(inode)->sb, KERN_WARNING,
-		"Unexpected flush for atomic writes: ino=%lu, npages=%lld",
+		"Unexpected flush for atomic writes: ino=%lu, npages=%u",
 					inode->i_ino, get_dirty_pages(inode));
 	ret = filemap_write_and_wait_range(inode->i_mapping, 0, LLONG_MAX);
 	if (ret)
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -565,13 +565,9 @@ static struct inode *f2fs_alloc_inode(st
 
 	init_once((void *) fi);
 
-	if (percpu_counter_init(&fi->dirty_pages, 0, GFP_NOFS)) {
-		kmem_cache_free(f2fs_inode_cachep, fi);
-		return NULL;
-	}
-
 	/* Initialize f2fs-specific inode info */
 	fi->vfs_inode.i_version = 1;
+	atomic_set(&fi->dirty_pages, 0);
 	fi->i_current_depth = 1;
 	fi->i_advise = 0;
 	init_rwsem(&fi->i_sem);
@@ -694,7 +690,6 @@ static void f2fs_i_callback(struct rcu_h
 
 static void f2fs_destroy_inode(struct inode *inode)
 {
-	percpu_counter_destroy(&F2FS_I(inode)->dirty_pages);
 	call_rcu(&inode->i_rcu, f2fs_i_callback);
 }