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| author | Theodore Ts'o <tytso@mit.edu> | 2011-10-29 08:24:18 -0400 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2011-10-29 08:24:18 -0400 |
| commit | 6cdbb0effc2f511ced23e46f2117e4b31d3d4a50 (patch) | |
| tree | a440c35498abfd171b619a398f1cee1b62be8219 /include/linux/fs.h | |
| parent | 80e675f906db54eb1ce3a9555cee5f45b5b72ab2 (diff) | |
| download | lwn-6cdbb0effc2f511ced23e46f2117e4b31d3d4a50.tar.gz lwn-6cdbb0effc2f511ced23e46f2117e4b31d3d4a50.zip | |
fs: optimize out 16 bytes worth of padding in struct inode
Rearrange the fields in struct inode so that on an x86_64 system,
fields that require 8-byte alignment don't end up causing 4-byte holes
in the structure. It reduces the size of struct inode from 568 bytes
to 552 bytes.
Also move the fields protected by i_lock (i_blocks, i_bytes, and
i_size) into the same cache line as i_lock.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Diffstat (limited to 'include/linux/fs.h')
| -rw-r--r-- | include/linux/fs.h | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/include/linux/fs.h b/include/linux/fs.h index 178cdb4f1d4a..fbda9a662f57 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -771,12 +771,13 @@ struct inode { unsigned long i_ino; unsigned int i_nlink; dev_t i_rdev; - loff_t i_size; struct timespec i_atime; struct timespec i_mtime; struct timespec i_ctime; - unsigned int i_blkbits; + spinlock_t i_lock; /* i_blocks, i_bytes, maybe i_size */ + unsigned short i_bytes; blkcnt_t i_blocks; + loff_t i_size; #ifdef __NEED_I_SIZE_ORDERED seqcount_t i_size_seqcount; @@ -784,7 +785,6 @@ struct inode { /* Misc */ unsigned long i_state; - spinlock_t i_lock; /* i_blocks, i_bytes, maybe i_size */ struct mutex i_mutex; unsigned long dirtied_when; /* jiffies of first dirtying */ @@ -798,9 +798,10 @@ struct inode { struct rcu_head i_rcu; }; atomic_t i_count; + unsigned int i_blkbits; u64 i_version; - unsigned short i_bytes; atomic_t i_dio_count; + atomic_t i_writecount; const struct file_operations *i_fop; /* former ->i_op->default_file_ops */ struct file_lock *i_flock; struct address_space i_data; @@ -824,7 +825,6 @@ struct inode { #ifdef CONFIG_IMA atomic_t i_readcount; /* struct files open RO */ #endif - atomic_t i_writecount; void *i_private; /* fs or device private pointer */ }; |