From a637120e49021d197e9578cba545bbaa459cbb51 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Thu, 19 Apr 2012 16:29:24 -0700 Subject: blkcg: use radix tree to index blkgs from blkcg blkg lookup is currently performed by traversing linked list anchored at blkcg->blkg_list. This is very unscalable and with blk-throttle enabled and enough request queues on the system, this can get very ugly quickly (blk-throttle performs look up on every bio submission). This patch makes blkcg use radix tree to index blkgs combined with simple last-looked-up hint. This is mostly identical to how icqs are indexed from ioc. Note that because __blkg_lookup() may be invoked without holding queue lock, hint is only updated from __blkg_lookup_create(). Due to cfq's cfqq caching, this makes hint updates overly lazy. This will be improved with scheduled blkcg aware request allocation. Signed-off-by: Tejun Heo Cc: Vivek Goyal Signed-off-by: Jens Axboe --- block/blk-cgroup.h | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'block/blk-cgroup.h') diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h index 44cb9086ed42..8ac457ce7783 100644 --- a/block/blk-cgroup.h +++ b/block/blk-cgroup.h @@ -16,6 +16,7 @@ #include #include #include +#include /* Max limits for throttle policy */ #define THROTL_IOPS_MAX UINT_MAX @@ -37,9 +38,14 @@ enum blkg_rwstat_type { BLKG_RWSTAT_TOTAL = BLKG_RWSTAT_NR, }; +struct blkcg_gq; + struct blkcg { struct cgroup_subsys_state css; spinlock_t lock; + + struct radix_tree_root blkg_tree; + struct blkcg_gq *blkg_hint; struct hlist_head blkg_list; /* for policies to test whether associated blkcg has changed */ -- cgit v1.2.3