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| author | Tejun Heo <tj@kernel.org> | 2012-04-19 16:29:24 -0700 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2012-04-20 10:06:40 +0200 |
| commit | a637120e49021d197e9578cba545bbaa459cbb51 (patch) | |
| tree | 0d502a8fcc55c89eb4d79a7578e46a9273d1f2c8 /block/blk-cgroup.h | |
| parent | 496fb7806d616185a46865a4f3a20ef19dc6c7e3 (diff) | |
| download | linux-a637120e49021d197e9578cba545bbaa459cbb51.tar.gz linux-a637120e49021d197e9578cba545bbaa459cbb51.tar.bz2 linux-a637120e49021d197e9578cba545bbaa459cbb51.zip | |
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.h | 6 |
1 files changed, 6 insertions, 0 deletions
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 <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 */ |