diff options
author | Paul Menage <menage@google.com> | 2008-04-29 01:00:01 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-04-29 08:06:08 -0700 |
commit | 9179656961adcea3c25403365597e486d851ac5e (patch) | |
tree | 13acbdd7ae045ed46fa679e613783717eb3b9138 /kernel/cgroup.c | |
parent | 700fe1ab99240c1a9c4d155e2a0612a1b044bb69 (diff) |
CGroup API files: add cgroup map data type
Adds a new type of supported control file representation, a map from strings
to u64 values.
Each map entry is printed as a line in a similar format to /proc/vmstat, i.e.
"$key $value\n"
Signed-off-by: Paul Menage <menage@google.com>
Cc: "Li Zefan" <lizf@cn.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: "YAMAMOTO Takashi" <yamamoto@valinux.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/cgroup.c')
-rw-r--r-- | kernel/cgroup.c | 53 |
1 files changed, 52 insertions, 1 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 57afdde871ac..693bcc03188b 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -1492,6 +1492,46 @@ static ssize_t cgroup_file_read(struct file *file, char __user *buf, return -EINVAL; } +/* + * seqfile ops/methods for returning structured data. Currently just + * supports string->u64 maps, but can be extended in future. + */ + +struct cgroup_seqfile_state { + struct cftype *cft; + struct cgroup *cgroup; +}; + +static int cgroup_map_add(struct cgroup_map_cb *cb, const char *key, u64 value) +{ + struct seq_file *sf = cb->state; + return seq_printf(sf, "%s %llu\n", key, (unsigned long long)value); +} + +static int cgroup_seqfile_show(struct seq_file *m, void *arg) +{ + struct cgroup_seqfile_state *state = m->private; + struct cftype *cft = state->cft; + struct cgroup_map_cb cb = { + .fill = cgroup_map_add, + .state = m, + }; + return cft->read_map(state->cgroup, cft, &cb); +} + +int cgroup_seqfile_release(struct inode *inode, struct file *file) +{ + struct seq_file *seq = file->private_data; + kfree(seq->private); + return single_release(inode, file); +} + +static struct file_operations cgroup_seqfile_operations = { + .read = seq_read, + .llseek = seq_lseek, + .release = cgroup_seqfile_release, +}; + static int cgroup_file_open(struct inode *inode, struct file *file) { int err; @@ -1504,7 +1544,18 @@ static int cgroup_file_open(struct inode *inode, struct file *file) cft = __d_cft(file->f_dentry); if (!cft) return -ENODEV; - if (cft->open) + if (cft->read_map) { + struct cgroup_seqfile_state *state = + kzalloc(sizeof(*state), GFP_USER); + if (!state) + return -ENOMEM; + state->cft = cft; + state->cgroup = __d_cgrp(file->f_dentry->d_parent); + file->f_op = &cgroup_seqfile_operations; + err = single_open(file, cgroup_seqfile_show, state); + if (err < 0) + kfree(state); + } else if (cft->open) err = cft->open(inode, file); else err = 0; |