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Commit d447ea2f authored by Pavel Emelyanov's avatar Pavel Emelyanov Committed by Linus Torvalds
Browse files

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: default avatarPavel Emelyanov <xemul@openvz.org>
Acked-by: default avatarPaul Menage <menage@google.com>
Acked-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 46ae220b

include/linux/cgroup.h

+8 −0
Original line number Diff line number Diff line
@@ -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);

};

kernel/cgroup.c

+4 −0
Original line number Diff line number Diff line
@@ -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;

}