From: Yu Kuai <yukuai3@huawei.com> mainline inclusion from mainline-v5.11-rc1 commit acaf523a7bf226b28504306c1cfee194520123b3 category: bugfix bugzilla: 185789 https://gitee.com/openeuler/kernel/issues/I4DDEL Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... --------------------------- blk_throtl_update_limit_valid() will search for descendants to see if 'LIMIT_LOW' of bps/iops and READ/WRITE is nonzero. However, they're always zero if CONFIG_BLK_DEV_THROTTLING_LOW is not set, furthermore, a lot of time will be wasted to iterate descendants. Thus do nothing in blk_throtl_update_limit_valid() in such situation. Signed-off-by: Yu Kuai <yukuai3@huawei.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk> Reviewed-by: Yufen Yu <yuyufen@huawei.com> Reviewed-by: Hou Tao <houtao1@huawei.com> Signed-off-by: Chen Jun <chenjun102@huawei.com> Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com> --- block/blk-throttle.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/block/blk-throttle.c b/block/blk-throttle.c index 4087dcc13f7d..3db507f33243 100644 --- a/block/blk-throttle.c +++ b/block/blk-throttle.c @@ -591,6 +591,7 @@ static void throtl_pd_online(struct blkg_policy_data *pd) tg_update_has_rules(tg); } +#ifdef CONFIG_BLK_DEV_THROTTLING_LOW static void blk_throtl_update_limit_valid(struct throtl_data *td) { struct cgroup_subsys_state *pos_css; @@ -611,6 +612,11 @@ static void blk_throtl_update_limit_valid(struct throtl_data *td) td->limit_valid[LIMIT_LOW] = low_valid; } +#else +static inline void blk_throtl_update_limit_valid(struct throtl_data *td) +{ +} +#endif static void throtl_upgrade_state(struct throtl_data *td); static void throtl_pd_offline(struct blkg_policy_data *pd) -- 2.20.1