From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: [PATCH 33/33] blk-throttle: implement proper hierarchy support Date: Mon, 6 May 2013 15:46:12 -0700 Message-ID: <1367880372-28312-34-git-send-email-tj@kernel.org> References: <1367880372-28312-1-git-send-email-tj@kernel.org> Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=x-received:sender:from:to:cc:subject:date:message-id:x-mailer :in-reply-to:references; bh=2cCgSFDi1yJ0Zd6JKdL+FDjxn7nMkT+ux2Uh+L25gxA=; b=Zygvc/gZtLWoZxPg1/KJWvDSzhTeeu1rgiHw35i3EMggg+9DwT+QyeRwSi3YBkbbHh Ul9sYCyKWUyJt2o6hLOWcLvbm7Uq5NufWljl78rIOJ2GoduSxvbOJk43ktfMVrVb1C3P c2fAe2rFkwbyu4qL55PYyWzLt3Rlfkhe5MkykeeIJ2OfOhxk463CmsuATtuMcTRMJ9XT mNrU9c2wR6xatoffAG/gNNuCEXhU6PnGYTWgwq/CE/QSbgT/fs2xw9HVupNJSS76P+NZ S07zCbHETqCzmRb6VOPW9jseiHgugEexG8c3iFkIzgDF0p+xzKtK+8V/dnH8e7C9ZxZd r0Ew== In-Reply-To: <1367880372-28312-1-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: axboe-tSWWG44O7X1aa/9Udqfwiw@public.gmane.org Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org, containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, vgoyal-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, Tejun Heo 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. Signed-off-by: Tejun Heo Cc: Li Zefan --- block/blk-cgroup.c | 8 -------- block/blk-throttle.c | 22 +++++++++++++++++++++- include/linux/cgroup.h | 2 ++ 3 files changed, 23 insertions(+), 9 deletions(-) diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index af2ca27..8d9edc8 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 27f006b..08a32df 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); diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index c371888..3c5f780 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -271,6 +271,8 @@ enum { * - memcg: use_hierarchy is on by default and the cgroup file for * the flag is not created. * + * - blkcg: blk-throttle becomes properly hierarchical. + * * The followings are planned changes. * * - release_agent will be disallowed once replacement notification -- 1.8.1.4