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cgroup_freezer: introduce CGROUP_FREEZING_[SELF|PARENT] 

Introduce FREEZING_SELF and FREEZING_PARENT and make FREEZING OR of
the two flags.  This is to prepare for full hierarchy support.

freezer_apply_date() is updated such that it can handle setting and
clearing of both flags.  The two flags are also exposed to userland
via read-only files self_freezing and parent_freezing.

Other than the added cgroupfs files, this patch doesn't introduce any
behavior change.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
This commit is contained in:
Tejun Heo 2012-11-09 09:12:30 -08:00
parent d6a2fe1342
commit a225218060
1 changed files with 47 additions and 8 deletions
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55
kernel/cgroup_freezer.c
View File

@ -23,8 +23,12 @@
#include <linux/seq_file.h>
enum freezer_state_flags {
CGROUP_FREEZING = (1 << 1), /* this freezer is freezing */
CGROUP_FREEZING_SELF = (1 << 1), /* this freezer is freezing */
CGROUP_FREEZING_PARENT = (1 << 2), /* the parent freezer is freezing */
CGROUP_FROZEN = (1 << 3), /* this and its descendants frozen */
/* mask for all FREEZING flags */
CGROUP_FREEZING = CGROUP_FREEZING_SELF | CGROUP_FREEZING_PARENT,
};
struct freezer {
@ -245,8 +249,13 @@ static void unfreeze_cgroup(struct freezer *freezer)
* freezer_apply_state - apply state change to a single cgroup_freezer
* @freezer: freezer to apply state change to
* @freeze: whether to freeze or unfreeze
* @state: CGROUP_FREEZING_* flag to set or clear
*
* Set or clear @state on @cgroup according to @freeze, and perform
* freezing or thawing as necessary.
*/
static void freezer_apply_state(struct freezer *freezer, bool freeze)
static void freezer_apply_state(struct freezer *freezer, bool freeze,
unsigned int state)
{
/* also synchronizes against task migration, see freezer_attach() */
lockdep_assert_held(&freezer->lock);
@ -254,13 +263,19 @@ static void freezer_apply_state(struct freezer *freezer, bool freeze)
if (freeze) {
if (!(freezer->state & CGROUP_FREEZING))
atomic_inc(&system_freezing_cnt);
freezer->state |= CGROUP_FREEZING;
freezer->state |= state;
freeze_cgroup(freezer);
} else {
if (freezer->state & CGROUP_FREEZING)
atomic_dec(&system_freezing_cnt);
freezer->state &= ~(CGROUP_FREEZING | CGROUP_FROZEN);
unfreeze_cgroup(freezer);
bool was_freezing = freezer->state & CGROUP_FREEZING;
freezer->state &= ~state;
if (!(freezer->state & CGROUP_FREEZING)) {
if (was_freezing)
atomic_dec(&system_freezing_cnt);
freezer->state &= ~CGROUP_FROZEN;
unfreeze_cgroup(freezer);
}
}
}
@ -275,7 +290,7 @@ static void freezer_change_state(struct freezer *freezer, bool freeze)
{
/* update @freezer */
spin_lock_irq(&freezer->lock);
freezer_apply_state(freezer, freeze);
freezer_apply_state(freezer, freeze, CGROUP_FREEZING_SELF);
spin_unlock_irq(&freezer->lock);
}
@ -295,6 +310,20 @@ static int freezer_write(struct cgroup *cgroup, struct cftype *cft,
return 0;
}
static u64 freezer_self_freezing_read(struct cgroup *cgroup, struct cftype *cft)
{
struct freezer *freezer = cgroup_freezer(cgroup);
return (bool)(freezer->state & CGROUP_FREEZING_SELF);
}
static u64 freezer_parent_freezing_read(struct cgroup *cgroup, struct cftype *cft)
{
struct freezer *freezer = cgroup_freezer(cgroup);
return (bool)(freezer->state & CGROUP_FREEZING_PARENT);
}
static struct cftype files[] = {
{
.name = "state",
@ -302,6 +331,16 @@ static struct cftype files[] = {
.read_seq_string = freezer_read,
.write_string = freezer_write,
},
{
.name = "self_freezing",
.flags = CFTYPE_NOT_ON_ROOT,
.read_u64 = freezer_self_freezing_read,
},
{
.name = "parent_freezing",
.flags = CFTYPE_NOT_ON_ROOT,
.read_u64 = freezer_parent_freezing_read,
},
{ } /* terminate */
};