From c23fbb6bcb3eb9cdf39a103edadf57bde8ce309c Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 8 May 2007 00:26:18 -0700 Subject: VFS: delay the dentry name generation on sockets and pipes 1) Introduces a new method in 'struct dentry_operations'. This method called d_dname() might be called from d_path() to build a pathname for special filesystems. It is called without locks. Future patches (if we succeed in having one common dentry for all pipes/sockets) may need to change prototype of this method, but we now use : char *d_dname(struct dentry *dentry, char *buffer, int buflen); 2) Adds a dynamic_dname() helper function that eases d_dname() implementations 3) Defines d_dname method for sockets : No more sprintf() at socket creation. This is delayed up to the moment someone does an access to /proc/pid/fd/... 4) Defines d_dname method for pipes : No more sprintf() at pipe creation. This is delayed up to the moment someone does an access to /proc/pid/fd/... A benchmark consisting of 1.000.000 calls to pipe()/close()/close() gives a *nice* speedup on my Pentium(M) 1.6 Ghz : 3.090 s instead of 3.450 s Signed-off-by: Eric Dumazet Acked-by: Christoph Hellwig Acked-by: Linus Torvalds Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/pipe.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) (limited to 'fs/pipe.c') diff --git a/fs/pipe.c b/fs/pipe.c index ebafde7d6ab..3a89592bdf5 100644 --- a/fs/pipe.c +++ b/fs/pipe.c @@ -841,8 +841,18 @@ static int pipefs_delete_dentry(struct dentry *dentry) return 0; } +/* + * pipefs_dname() is called from d_path(). + */ +static char *pipefs_dname(struct dentry *dentry, char *buffer, int buflen) +{ + return dynamic_dname(dentry, buffer, buflen, "pipe:[%lu]", + dentry->d_inode->i_ino); +} + static struct dentry_operations pipefs_dentry_operations = { .d_delete = pipefs_delete_dentry, + .d_dname = pipefs_dname, }; static struct inode * get_pipe_inode(void) @@ -888,8 +898,7 @@ struct file *create_write_pipe(void) struct inode *inode; struct file *f; struct dentry *dentry; - char name[32]; - struct qstr this; + struct qstr name = { .name = "" }; f = get_empty_filp(); if (!f) @@ -899,11 +908,8 @@ struct file *create_write_pipe(void) if (!inode) goto err_file; - this.len = sprintf(name, "[%lu]", inode->i_ino); - this.name = name; - this.hash = 0; err = -ENOMEM; - dentry = d_alloc(pipe_mnt->mnt_sb->s_root, &this); + dentry = d_alloc(pipe_mnt->mnt_sb->s_root, &name); if (!dentry) goto err_inode; -- cgit v1.2.3