ceph: reduce i_nr_by_mode array size

Track usage count for individual fmode bit. This can reduce the
array size by half.
Signed-off-by: Yan, Zheng <zyan@redhat.com>

fs/ceph/caps.c

@@ -849,12 +849,14 @@ int __ceph_caps_used(struct ceph_inode_info *ci)
  */
 int __ceph_caps_file_wanted(struct ceph_inode_info *ci)
 {
-	int want = 0;
-	int mode;
-	for (mode = 0; mode < CEPH_FILE_MODE_NUM; mode++)
-		if (ci->i_nr_by_mode[mode])
-			want |= ceph_caps_for_mode(mode);
-	return want;
+	int i, bits = 0;
+	for (i = 0; i < CEPH_FILE_MODE_BITS; i++) {
+		if (ci->i_nr_by_mode[i])
+			bits |= 1 << i;
+	}
+	if (bits == 0)
+		return 0;
+	return ceph_caps_for_mode(bits >> 1);
 }
 
 /*
@@ -3682,6 +3684,16 @@ void ceph_flush_dirty_caps(struct ceph_mds_client *mdsc)
 	dout("flush_dirty_caps done\n");
 }
 
+void __ceph_get_fmode(struct ceph_inode_info *ci, int fmode)
+{
+	int i;
+	int bits = (fmode << 1) | 1;
+	for (i = 0; i < CEPH_FILE_MODE_BITS; i++) {
+		if (bits & (1 << i))
+			ci->i_nr_by_mode[i]++;
+	}
+}
+
 /*
  * Drop open file reference.  If we were the last open file,
  * we may need to release capabilities to the MDS (or schedule
@@ -3689,15 +3701,20 @@ void ceph_flush_dirty_caps(struct ceph_mds_client *mdsc)
  */
 void ceph_put_fmode(struct ceph_inode_info *ci, int fmode)
 {
-	struct inode *inode = &ci->vfs_inode;
-	int last = 0;
-
+	int i, last = 0;
+	int bits = (fmode << 1) | 1;
 	spin_lock(&ci->i_ceph_lock);
-	dout("put_fmode %p fmode %d %d -> %d\n", inode, fmode,
-	     ci->i_nr_by_mode[fmode], ci->i_nr_by_mode[fmode]-1);
-	BUG_ON(ci->i_nr_by_mode[fmode] == 0);
-	if (--ci->i_nr_by_mode[fmode] == 0)
+	for (i = 0; i < CEPH_FILE_MODE_BITS; i++) {
+		if (bits & (1 << i)) {
+			BUG_ON(ci->i_nr_by_mode[i] == 0);
+			if (--ci->i_nr_by_mode[i] == 0)
 				last++;
+		}
+	}
+	dout("put_fmode %p fmode %d {%d,%d,%d,%d}\n",
+	     &ci->vfs_inode, fmode,
+	     ci->i_nr_by_mode[0], ci->i_nr_by_mode[1],
+	     ci->i_nr_by_mode[2], ci->i_nr_by_mode[3]);
 	spin_unlock(&ci->i_ceph_lock);
 
 	if (last && ci->i_vino.snap == CEPH_NOSNAP)

fs/ceph/inode.c

@@ -477,7 +477,7 @@ struct inode *ceph_alloc_inode(struct super_block *sb)
 	ci->i_head_snapc = NULL;
 	ci->i_snap_caps = 0;
 
-	for (i = 0; i < CEPH_FILE_MODE_NUM; i++)
+	for (i = 0; i < CEPH_FILE_MODE_BITS; i++)
 		ci->i_nr_by_mode[i] = 0;
 
 	mutex_init(&ci->i_truncate_mutex);

fs/ceph/ioctl.c

@@ -250,9 +250,8 @@ static long ceph_ioctl_lazyio(struct file *file)
 
 	if ((fi->fmode & CEPH_FILE_MODE_LAZY) == 0) {
 		spin_lock(&ci->i_ceph_lock);
-		ci->i_nr_by_mode[fi->fmode]--;
 		fi->fmode |= CEPH_FILE_MODE_LAZY;
-		ci->i_nr_by_mode[fi->fmode]++;
+		ci->i_nr_by_mode[ffs(CEPH_FILE_MODE_LAZY)]++;
 		spin_unlock(&ci->i_ceph_lock);
 		dout("ioctl_layzio: file %p marked lazy\n", file);
 

fs/ceph/super.h

@@ -321,7 +321,7 @@ struct ceph_inode_info {
 						    dirty|flushing caps */
 	unsigned i_snap_caps;           /* cap bits for snapped files */
 
-	int i_nr_by_mode[CEPH_FILE_MODE_NUM];  /* open file counts */
+	int i_nr_by_mode[CEPH_FILE_MODE_BITS];  /* open file counts */
 
 	struct mutex i_truncate_mutex;
 	u32 i_truncate_seq;        /* last truncate to smaller size */
@@ -906,10 +906,7 @@ extern int ceph_get_caps(struct ceph_inode_info *ci, int need, int want,
 			 loff_t endoff, int *got, struct page **pinned_page);
 
 /* for counting open files by mode */
-static inline void __ceph_get_fmode(struct ceph_inode_info *ci, int mode)
-{
-	ci->i_nr_by_mode[mode]++;
-}
+extern void __ceph_get_fmode(struct ceph_inode_info *ci, int mode);
 extern void ceph_put_fmode(struct ceph_inode_info *ci, int mode);
 
 /* addr.c */

include/linux/ceph/ceph_fs.h

@@ -525,7 +525,7 @@ struct ceph_filelock {
 #define CEPH_FILE_MODE_WR         2
 #define CEPH_FILE_MODE_RDWR       3  /* RD | WR */
 #define CEPH_FILE_MODE_LAZY       4  /* lazy io */
-#define CEPH_FILE_MODE_NUM        8  /* bc these are bit fields.. mostly */
+#define CEPH_FILE_MODE_BITS       4
 
 int ceph_flags_to_mode(int flags);