cgroup: replace cgroup_on_dfl() tests in controllers with cgroup_subsys_on_dfl()

cgroup_on_dfl() tests whether the cgroup's root is the default
hierarchy; however, an individual controller is only interested in
whether the controller is attached to the default hierarchy and never
tests a cgroup which doesn't belong to the hierarchy that the
controller is attached to.

This patch replaces cgroup_on_dfl() tests in controllers with faster
static_key based cgroup_subsys_on_dfl().  This leaves cgroup core as
the only user of cgroup_on_dfl() and the function is moved from the
header file to cgroup.c.

Signed-off-by: Tejun Heo <[email protected]>
Acked-by: Zefan Li <[email protected]>
Cc: Vivek Goyal <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Michal Hocko <[email protected]>
This commit is contained in:
Tejun Heo 2015-09-18 11:56:28 -04:00
commit 9e10a130d9
6 changed files with 76 additions and 73 deletions

View file

@ -369,7 +369,7 @@ static void throtl_pd_init(struct blkg_policy_data *pd)
* regardless of the position of the group in the hierarchy.
*/
sq->parent_sq = &td->service_queue;
if (cgroup_on_dfl(blkg->blkcg->css.cgroup) && blkg->parent)
if (cgroup_subsys_on_dfl(io_cgrp_subsys) && blkg->parent)
sq->parent_sq = &blkg_to_tg(blkg->parent)->service_queue;
tg->td = td;
}

View file

@ -1581,7 +1581,7 @@ static struct blkcg_policy_data *cfq_cpd_alloc(gfp_t gfp)
static void cfq_cpd_init(struct blkcg_policy_data *cpd)
{
struct cfq_group_data *cgd = cpd_to_cfqgd(cpd);
unsigned int weight = cgroup_on_dfl(blkcg_root.css.cgroup) ?
unsigned int weight = cgroup_subsys_on_dfl(io_cgrp_subsys) ?
CGROUP_WEIGHT_DFL : CFQ_WEIGHT_LEGACY_DFL;
if (cpd_to_blkcg(cpd) == &blkcg_root)
@ -1599,7 +1599,7 @@ static void cfq_cpd_free(struct blkcg_policy_data *cpd)
static void cfq_cpd_bind(struct blkcg_policy_data *cpd)
{
struct blkcg *blkcg = cpd_to_blkcg(cpd);
bool on_dfl = cgroup_on_dfl(blkcg_root.css.cgroup);
bool on_dfl = cgroup_subsys_on_dfl(io_cgrp_subsys);
unsigned int weight = on_dfl ? CGROUP_WEIGHT_DFL : CFQ_WEIGHT_LEGACY_DFL;
if (blkcg == &blkcg_root)