aboutsummaryrefslogtreecommitdiff
path: root/block
diff options
context:
space:
mode:
authorTejun Heo <tj@kernel.org>2013-05-14 13:52:38 -0700
committerTejun Heo <tj@kernel.org>2013-05-14 13:52:38 -0700
commit9138125beabbb76b4a373d4a619870f6f5d86fc5 (patch)
tree61ccabf042ff21b81c6dcd074ea8edeb77fedfa8 /block
parent693e751e70843c29884cde326016e746fa16073a (diff)
downloadlinux-linaro-stable-9138125beabbb76b4a373d4a619870f6f5d86fc5.tar.gz
blk-throttle: implement proper hierarchy support
With the recent updates, blk-throttle is finally ready for proper hierarchy support. Dispatching now honors service_queue->parent_sq and propagates correctly. The only thing missing is setting ->parent_sq correctly so that throtl_grp hierarchy matches the cgroup hierarchy. This patch updates throtl_pd_init() such that service_queues form the same hierarchy as the cgroup hierarchy if sane_behavior is enabled. As this concludes proper hierarchy support for blkcg, the shameful .broken_hierarchy tag is removed from blkio_subsys. v2: Updated blkio-controller.txt as suggested by Vivek. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com> Cc: Li Zefan <lizefan@huawei.com>
Diffstat (limited to 'block')
-rw-r--r--block/blk-cgroup.c8
-rw-r--r--block/blk-throttle.c22
2 files changed, 21 insertions, 9 deletions
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index d0747605f56c..290792a13e3c 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -911,14 +911,6 @@ struct cgroup_subsys blkio_subsys = {
.subsys_id = blkio_subsys_id,
.base_cftypes = blkcg_files,
.module = THIS_MODULE,
-
- /*
- * blkio subsystem is utterly broken in terms of hierarchy support.
- * It treats all cgroups equally regardless of where they're
- * located in the hierarchy - all cgroups are treated as if they're
- * right below the root. Fix it and remove the following.
- */
- .broken_hierarchy = true,
};
EXPORT_SYMBOL_GPL(blkio_subsys);
diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index 27f006bb363b..08a32dfd3844 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -397,10 +397,30 @@ static void throtl_pd_init(struct blkcg_gq *blkg)
{
struct throtl_grp *tg = blkg_to_tg(blkg);
struct throtl_data *td = blkg->q->td;
+ struct throtl_service_queue *parent_sq;
unsigned long flags;
int rw;
- throtl_service_queue_init(&tg->service_queue, &td->service_queue);
+ /*
+ * If sane_hierarchy is enabled, we switch to properly hierarchical
+ * behavior where limits on a given throtl_grp are applied to the
+ * whole subtree rather than just the group itself. e.g. If 16M
+ * read_bps limit is set on the root group, the whole system can't
+ * exceed 16M for the device.
+ *
+ * If sane_hierarchy is not enabled, the broken flat hierarchy
+ * behavior is retained where all throtl_grps are treated as if
+ * they're all separate root groups right below throtl_data.
+ * Limits of a group don't interact with limits of other groups
+ * regardless of the position of the group in the hierarchy.
+ */
+ parent_sq = &td->service_queue;
+
+ if (cgroup_sane_behavior(blkg->blkcg->css.cgroup) && blkg->parent)
+ parent_sq = &blkg_to_tg(blkg->parent)->service_queue;
+
+ throtl_service_queue_init(&tg->service_queue, parent_sq);
+
for (rw = READ; rw <= WRITE; rw++) {
throtl_qnode_init(&tg->qnode_on_self[rw], tg);
throtl_qnode_init(&tg->qnode_on_parent[rw], tg);