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| author | Eric Dumazet <dada1@cosmosbay.com> | 2005-10-30 15:02:16 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2005-10-30 17:37:19 -0800 |
| commit | 2f51201662b28dbf8c15fb7eb972bc51c6cc3fa5 (patch) | |
| tree | 96826df796058560bc5dd1f7d8d476c5a741d7bc /include/linux/fs.h | |
| parent | 503af334ecf23b9d65d2ff0cc759f3a0bf338290 (diff) | |
| download | lwn-2f51201662b28dbf8c15fb7eb972bc51c6cc3fa5.tar.gz lwn-2f51201662b28dbf8c15fb7eb972bc51c6cc3fa5.zip | |
[PATCH] reduce sizeof(struct file)
Now that RCU applied on 'struct file' seems stable, we can place f_rcuhead
in a memory location that is not anymore used at call_rcu(&f->f_rcuhead,
file_free_rcu) time, to reduce the size of this critical kernel object.
The trick I used is to move f_rcuhead and f_list in an union called f_u
The callers are changed so that f_rcuhead becomes f_u.fu_rcuhead and f_list
becomes f_u.f_list
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'include/linux/fs.h')
| -rw-r--r-- | include/linux/fs.h | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/include/linux/fs.h b/include/linux/fs.h index f83d997c5582..6d6226732c93 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -574,7 +574,14 @@ struct file_ra_state { #define RA_FLAG_INCACHE 0x02 /* file is already in cache */ struct file { - struct list_head f_list; + /* + * fu_list becomes invalid after file_free is called and queued via + * fu_rcuhead for RCU freeing + */ + union { + struct list_head fu_list; + struct rcu_head fu_rcuhead; + } f_u; struct dentry *f_dentry; struct vfsmount *f_vfsmnt; struct file_operations *f_op; @@ -598,7 +605,6 @@ struct file { spinlock_t f_ep_lock; #endif /* #ifdef CONFIG_EPOLL */ struct address_space *f_mapping; - struct rcu_head f_rcuhead; }; extern spinlock_t files_lock; #define file_list_lock() spin_lock(&files_lock); |