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authorChristoph Hellwig <hch@lst.de>2007-02-12 03:51:58 -0500
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-02-12 12:48:28 -0500
commitd003fb70fd356d0684ee0cd37a785e058c8678de (patch)
tree2367a8afa16defd85633665fbdb2a9192cbe6081
parentfb58b7316a99703afb8d076b0e5f3e1e387e4b30 (diff)
[PATCH] remove sb->s_files and file_list_lock usage in dquot.c
Iterate over sb->s_inodes instead of sb->s_files in add_dquot_ref. This reduces list search and lock hold time aswell as getting rid of one of the few uses of file_list_lock which Ingo identified as a scalability problem. Previously we called dq_op->initialize for every inode handing of a writeable file that wasn't initialized before. Now we're calling it for every inode that has a non-zero i_writecount, aka a writeable file descriptor refering to it. Thanks a lot to Jan Kara for running this patch through his quota test harness. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/dquot.c32
1 files changed, 18 insertions, 14 deletions
diff --git a/fs/dquot.c b/fs/dquot.c
index 5bdc4b2a872a..9eb166f91489 100644
--- a/fs/dquot.c
+++ b/fs/dquot.c
@@ -688,23 +688,27 @@ static int dqinit_needed(struct inode *inode, int type)
688/* This routine is guarded by dqonoff_mutex mutex */ 688/* This routine is guarded by dqonoff_mutex mutex */
689static void add_dquot_ref(struct super_block *sb, int type) 689static void add_dquot_ref(struct super_block *sb, int type)
690{ 690{
691 struct list_head *p; 691 struct inode *inode;
692 692
693restart: 693restart:
694 file_list_lock(); 694 spin_lock(&inode_lock);
695 list_for_each(p, &sb->s_files) { 695 list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
696 struct file *filp = list_entry(p, struct file, f_u.fu_list); 696 if (!atomic_read(&inode->i_writecount))
697 struct inode *inode = filp->f_path.dentry->d_inode; 697 continue;
698 if (filp->f_mode & FMODE_WRITE && dqinit_needed(inode, type)) { 698 if (!dqinit_needed(inode, type))
699 struct dentry *dentry = dget(filp->f_path.dentry); 699 continue;
700 file_list_unlock(); 700 if (inode->i_state & (I_FREEING|I_WILL_FREE))
701 sb->dq_op->initialize(inode, type); 701 continue;
702 dput(dentry); 702
703 /* As we may have blocked we had better restart... */ 703 __iget(inode);
704 goto restart; 704 spin_unlock(&inode_lock);
705 } 705
706 sb->dq_op->initialize(inode, type);
707 iput(inode);
708 /* As we may have blocked we had better restart... */
709 goto restart;
706 } 710 }
707 file_list_unlock(); 711 spin_unlock(&inode_lock);
708} 712}
709 713
710/* Return 0 if dqput() won't block (note that 1 doesn't necessarily mean blocking) */ 714/* Return 0 if dqput() won't block (note that 1 doesn't necessarily mean blocking) */