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authorPavel Emelyanov <xemul@openvz.org>2008-04-29 01:00:08 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-04-29 08:06:09 -0700
commitd447ea2f30ec60370ddb99a668e5ac12995f043d (patch)
treef5d53c03d32323f3e916237f8ec0e0b2572f93b0
parent46ae220bea40bd1cf4abec2d5cdfb4f9396c7115 (diff)
cgroups: add the trigger callback to struct cftype
Trigger callback can be used to receive a kick-up from the user space. The string written is ignored. The cftype->private is used for multiplexing events. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Acked-by: Paul Menage <menage@google.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--include/linux/cgroup.h8
-rw-r--r--kernel/cgroup.c4
2 files changed, 12 insertions, 0 deletions
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 785a01cfb49..2d1d151258c 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -243,6 +243,14 @@ struct cftype {
*/
int (*write_s64) (struct cgroup *cgrp, struct cftype *cft, s64 val);
+ /*
+ * trigger() callback can be used to get some kick from the
+ * userspace, when the actual string written is not important
+ * at all. The private field can be used to determine the
+ * kick type for multiplexing.
+ */
+ int (*trigger)(struct cgroup *cgrp, unsigned int event);
+
int (*release) (struct inode *inode, struct file *file);
};
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 436e26f4d62..7c8cc514187 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1410,6 +1410,10 @@ static ssize_t cgroup_file_write(struct file *file, const char __user *buf,
return cft->write(cgrp, cft, file, buf, nbytes, ppos);
if (cft->write_u64 || cft->write_s64)
return cgroup_write_X64(cgrp, cft, file, buf, nbytes, ppos);
+ if (cft->trigger) {
+ int ret = cft->trigger(cgrp, (unsigned int)cft->private);
+ return ret ? ret : nbytes;
+ }
return -EINVAL;
}