From 9138125beabbb76b4a373d4a619870f6f5d86fc5 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Tue, 14 May 2013 13:52:38 -0700 Subject: 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 Acked-by: Vivek Goyal Cc: Li Zefan --- block/blk-cgroup.c | 8 -------- block/blk-throttle.c | 22 +++++++++++++++++++++- 2 files changed, 21 insertions(+), 9 deletions(-) (limited to 'block') 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); -- cgit v1.2.3