From: Xunlei Pang xlpang@linux.alibaba.com
[ Upstream commit 4f44657d74873735e93a50eb25014721a66aac19 ]
The current blkio.throttle.io_service_bytes_recursive doesn't work correctly.
As an example, for the following blkcg hierarchy: (Made 1GB READ in test1, 512MB READ in test2) test / \ test1 test2
$ head -n 1 test/test1/blkio.throttle.io_service_bytes_recursive 8:0 Read 1073684480 $ head -n 1 test/test2/blkio.throttle.io_service_bytes_recursive 8:0 Read 537448448 $ head -n 1 test/blkio.throttle.io_service_bytes_recursive 8:0 Read 537448448
Clearly, above data of "test" reflects "test2" not "test1"+"test2".
Do the correct summary in blkg_rwstat_recursive_sum().
Signed-off-by: Xunlei Pang xlpang@linux.alibaba.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Sasha Levin sashal@kernel.org --- block/blk-cgroup-rwstat.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/block/blk-cgroup-rwstat.c b/block/blk-cgroup-rwstat.c index 85d5790ac49b..3304e841df7c 100644 --- a/block/blk-cgroup-rwstat.c +++ b/block/blk-cgroup-rwstat.c @@ -109,6 +109,7 @@ void blkg_rwstat_recursive_sum(struct blkcg_gq *blkg, struct blkcg_policy *pol,
lockdep_assert_held(&blkg->q->queue_lock);
+ memset(sum, 0, sizeof(*sum)); rcu_read_lock(); blkg_for_each_descendant_pre(pos_blkg, pos_css, blkg) { struct blkg_rwstat *rwstat; @@ -122,7 +123,7 @@ void blkg_rwstat_recursive_sum(struct blkcg_gq *blkg, struct blkcg_policy *pol, rwstat = (void *)pos_blkg + off;
for (i = 0; i < BLKG_RWSTAT_NR; i++) - sum->cnt[i] = blkg_rwstat_read_counter(rwstat, i); + sum->cnt[i] += blkg_rwstat_read_counter(rwstat, i); } rcu_read_unlock(); }