[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>
diff --git a/fs/dquot.c b/fs/dquot.c
index 05f3327..ea76442 100644
--- a/fs/dquot.c
+++ b/fs/dquot.c
@@ -662,7 +662,7 @@
restart:
file_list_lock();
list_for_each(p, &sb->s_files) {
- struct file *filp = list_entry(p, struct file, f_list);
+ struct file *filp = list_entry(p, struct file, f_u.fu_list);
struct inode *inode = filp->f_dentry->d_inode;
if (filp->f_mode & FMODE_WRITE && dqinit_needed(inode, type)) {
struct dentry *dentry = dget(filp->f_dentry);