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authorArtem Bityutskiy <Artem.Bityutskiy@nokia.com>2008-11-01 14:20:50 +0200
committerArtem Bityutskiy <Artem.Bityutskiy@nokia.com>2008-12-03 13:13:59 +0200
commita1dc080c27ec8ea7ca1c8a9b499362a71ebff792 (patch)
treea41c931fb6f7c8bdc0c3481545892216921074eb /fs/ubifs
parent062e4fee4400f283307cf8ac1b7931c939010229 (diff)
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: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Diffstat (limited to 'fs/ubifs')
-rw-r--r--fs/ubifs/super.c8
-rw-r--r--fs/ubifs/ubifs.h6
2 files changed, 11 insertions, 3 deletions
diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
index d80b2aef42b..21b4103271e 100644
--- a/fs/ubifs/super.c
+++ b/fs/ubifs/super.c
@@ -2021,6 +2021,14 @@ static int __init ubifs_init(void)
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.
*/
diff --git a/fs/ubifs/ubifs.h b/fs/ubifs/ubifs.h
index 46b172560a0..4d76aba57ee 100644
--- a/fs/ubifs/ubifs.h
+++ b/fs/ubifs/ubifs.h
@@ -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);