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Commit 56c807ba authored by Tejun Heo's avatar Tejun Heo
Browse files

cgroup: add cgroup_subsys->css_e_css_changed() 



Add a new cgroup_subsys operatoin ->css_e_css_changed().  This is
invoked if any of the effective csses seen from the css's cgroup may
have changed.  This will be used to implement cgroup writeback
support.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Acked-by: default avatarZefan Li <lizefan@huawei.com>
parent 7d172cc8

include/linux/cgroup.h

+1 −0
Original line number Diff line number Diff line
@@ -615,6 +615,7 @@ struct cgroup_subsys { 
	void (*css_released)(struct cgroup_subsys_state *css);

	void (*css_free)(struct cgroup_subsys_state *css);

	void (*css_reset)(struct cgroup_subsys_state *css);

	void (*css_e_css_changed)(struct cgroup_subsys_state *css);



	int (*can_attach)(struct cgroup_subsys_state *css,

			  struct cgroup_taskset *tset);

kernel/cgroup.c

+18 −0
Original line number Diff line number Diff line
@@ -2836,6 +2836,24 @@ static ssize_t cgroup_subtree_control_write(struct kernfs_open_file *of, 
		}

	}



	/*

	 * The effective csses of all the descendants (excluding @cgrp) may

	 * have changed.  Subsystems can optionally subscribe to this event

	 * by implementing ->css_e_css_changed() which is invoked if any of

	 * the effective csses seen from the css's cgroup may have changed.

	 */

	for_each_subsys(ss, ssid) {

		struct cgroup_subsys_state *this_css = cgroup_css(cgrp, ss);

		struct cgroup_subsys_state *css;



		if (!ss->css_e_css_changed || !this_css)

			continue;



		css_for_each_descendant_pre(css, this_css)

			if (css != this_css)

				ss->css_e_css_changed(css);

	}



	kernfs_activate(cgrp->kn);

	ret = 0;

out_unlock: