Re: [PATCH 13/16] cgroup_freezer: prepare for removal of TIF_FREEZE

[Oleg Nesterov]

Hi Tejun.

Well, yet another sorry for delay ;)

On 08/19, Tejun Heo wrote:
>
> @@ -279,7 +268,6 @@ static int try_to_freeze_cgroup(struct cgroup *cgroup, struct freezer *freezer)
>  	struct task_struct *task;
>  	unsigned int num_cant_freeze_now = 0;
>
> -	freezer->state = CGROUP_FREEZING;

...

> @@ -321,6 +307,8 @@ static int freezer_change_state(struct cgroup *cgroup,
>  	if (goal_state == freezer->state)
>  		goto out;
>
> +	freezer->state = goal_state;
> +

This doesn't look right at all... Unless I misssed something.

A user writes "FROZEN" into the control file, our goal is CGROUP_FROZEN.

But. freezer_change_state() should set CGROUP_FREEZING, not CGROUP_FROZEN.
This cgrp is not frozen yet, _FROZEN should be set by update_if_frozen(),
assuming that the user reads the state waiting until the operation
completes.

Oleg.

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