Commit a1dc080c authored by Artem Bityutskiy's avatar Artem Bityutskiy
Browse files

UBIFS: use bit-fields to store compression type 



Save a 4 bytes of RAM per 'struct inode' by stroring inode
compression type in bit-filed, instead of using 'int'.

Signed-off-by: default avatarArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
parent 062e4fee

fs/ubifs/super.c

+8 −0
Original line number Diff line number Diff line
@@ -2020,6 +2020,14 @@ static int __init ubifs_init(void) 
	BUILD_BUG_ON(UBIFS_INO_NODE_SZ != 160);

	BUILD_BUG_ON(UBIFS_REF_NODE_SZ != 64);



	/*

	 * We use 2 bit wide bit-fields to store compression type, which should

	 * be amended if more compressors are added. The bit-fields are:

	 * @compr_type in 'struct ubifs_inode' and @default_compr in

	 * 'struct ubifs_info'.

	 */

	BUILD_BUG_ON(UBIFS_COMPR_TYPES_CNT > 4);



	/*

	 * We require that PAGE_CACHE_SIZE is greater-than-or-equal-to

	 * UBIFS_BLOCK_SIZE. It is assumed that both are powers of 2.

fs/ubifs/ubifs.h

+3 −3
Original line number Diff line number Diff line
@@ -386,12 +386,12 @@ struct ubifs_inode { 
	unsigned int dirty:1;

	unsigned int xattr:1;

	unsigned int bulk_read:1;

	unsigned int compr_type:2;

	struct mutex ui_mutex;

	spinlock_t ui_lock;

	loff_t synced_i_size;

	loff_t ui_size;

	int flags;

	int compr_type;

	pgoff_t last_page_read;

	pgoff_t read_in_a_row;

	int data_len;
@@ -946,6 +946,7 @@ struct ubifs_mount_opts { 
 * @no_chk_data_crc: do not check CRCs when reading data nodes (except during

 *                   recovery)

 * @bulk_read: enable bulk-reads

 * @default_compr: default compression algorithm (%UBIFS_COMPR_LZO, etc)

 *

 * @tnc_mutex: protects the Tree Node Cache (TNC), @zroot, @cnext, @enext, and

 *             @calc_idx_sz
@@ -986,7 +987,6 @@ struct ubifs_mount_opts { 
 * @main_lebs: count of LEBs in the main area

 * @main_first: first LEB of the main area

 * @main_bytes: main area size in bytes

 * @default_compr: default compression algorithm (%UBIFS_COMPR_LZO, etc)

 *

 * @key_hash_type: type of the key hash

 * @key_hash: direntry key hash function
@@ -1196,6 +1196,7 @@ struct ubifs_info { 
	unsigned int big_lpt:1;

	unsigned int no_chk_data_crc:1;

	unsigned int bulk_read:1;

	unsigned int default_compr:2;



	struct mutex tnc_mutex;

	struct ubifs_zbranch zroot;
@@ -1237,7 +1238,6 @@ struct ubifs_info { 
	int main_lebs;

	int main_first;

	long long main_bytes;

	int default_compr;



	uint8_t key_hash_type;

	uint32_t (*key_hash)(const char *str, int len);