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authorTejun Heo <tj@kernel.org>2012-04-19 16:29:24 -0700
committerJens Axboe <axboe@kernel.dk>2012-04-20 10:06:40 +0200
commita637120e49021d197e9578cba545bbaa459cbb51 (patch)
tree0d502a8fcc55c89eb4d79a7578e46a9273d1f2c8 /block/blk-cgroup.h
parent496fb7806d616185a46865a4f3a20ef19dc6c7e3 (diff)
downloadop-kernel-dev-a637120e49021d197e9578cba545bbaa459cbb51.zip
op-kernel-dev-a637120e49021d197e9578cba545bbaa459cbb51.tar.gz
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 <tj@kernel.org> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/blk-cgroup.h')
-rw-r--r--block/blk-cgroup.h6
1 files changed, 6 insertions, 0 deletions
diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h
index 44cb908..8ac457c 100644
--- a/block/blk-cgroup.h
+++ b/block/blk-cgroup.h
@@ -16,6 +16,7 @@
#include <linux/cgroup.h>
#include <linux/u64_stats_sync.h>
#include <linux/seq_file.h>
+#include <linux/radix-tree.h>
/* 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 */
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