lkml.org 
[lkml]   [2008]   [Nov]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH -last version] freezer_cg: disable writing freezer.state of root cgroup
> I would make a small macro is_root_freezer() to show explicitly
> what we are testing and use the CSS_ROOT bit to test. That's what
> the CSS_ROOT bit is for Paul ?
>

I think yes CSS_ROOT can be used, though currently CSS_ROOT is used in
cgroup internal only (in css_get() and css_put()).

> if yes, here's a possible result is below.
>

is_root_freezer() looks a bit better, but I don't have strong option about
this change, the original code and the comment is enough to explain what
we are doing.

> C.
>
> Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
> ---
> kernel/cgroup_freezer.c | 15 +++++++++++++++
> 1 file changed, 15 insertions(+)
>
> Index: 2.6.27-lxc/kernel/cgroup_freezer.c
> ===================================================================
> --- 2.6.27-lxc.orig/kernel/cgroup_freezer.c
> +++ 2.6.27-lxc/kernel/cgroup_freezer.c
> @@ -47,6 +47,11 @@ static inline struct freezer *task_freez
> struct freezer, css);
> }
>
> +static inline int is_root_freezer(struct freezer *freezer)
> +{
> + return test_bit(CSS_ROOT, &freezer->css.flags);
> +}
> +
> int cgroup_frozen(struct task_struct *task)
> {
> struct freezer *freezer;
> @@ -190,6 +195,13 @@ static void freezer_fork(struct cgroup_s
> freezer = task_freezer(task);
> task_unlock(task);
>
> + /*
> + * The root cgroup is non-freezable, so we can skip the
> + * following check.
> + */
> + if (is_root_freezer(freezer))
> + return;
> +
> BUG_ON(freezer->state == CGROUP_FROZEN);
> spin_lock_irq(&freezer->lock);
> /* Locking avoids race with FREEZING -> THAWED transitions. */
> @@ -363,6 +375,9 @@ static struct cftype files[] = {
>
> static int freezer_populate(struct cgroup_subsys *ss, struct cgroup *cgroup)
> {
> + if (is_root_freezer(cgroup_freezer(cgroup)))
> + return 0;
> +
> return cgroup_add_files(cgroup, ss, files, ARRAY_SIZE(files));
> }
>



\
 
 \ /
  Last update: 2008-11-07 08:05    [W:0.036 / U:0.020 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site