[PATCH v2 08/10] blk-throttle: remove repeat check of elapsed time from last upgrade in throtl_hierarchy_can_downgrade

Kemeng Shi
2022-11-29T03:02:31Z

There is no need to check elapsed time from last upgrade for each node in
hierarchy. Move this check before traversing as throtl_can_upgrade do
to remove repeat check.

Signed-off-by: Kemeng Shi <shikemeng@huawei.com>
Reported-by: kernel test robot <lkp@intel.com>
---
block/blk-throttle.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index 3ddd8a15aa3f..94d850b57462 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -1955,8 +1955,7 @@ static bool throtl_tg_can_downgrade(struct throtl_grp *tg)
* If cgroup is below low limit, consider downgrade and throttle other
* cgroups
*/
- if (time_after_eq(now, td->low_upgrade_time + td->throtl_slice) &&
- time_after_eq(now, tg_last_low_overflow_time(tg) +
+ if (time_after_eq(now, tg_last_low_overflow_time(tg) +
td->throtl_slice) &&
(!throtl_tg_is_idle(tg) ||
!list_empty(&tg_to_blkg(tg)->blkcg->css.children)))
@@ -1966,6 +1965,11 @@ static bool throtl_tg_can_downgrade(struct throtl_grp *tg)

static bool throtl_hierarchy_can_downgrade(struct throtl_grp *tg)
{
+ struct throtl_data *td = tg->td;
+
+ if (time_before(jiffies, td->low_upgrade_time + td->throtl_slice))
+ return false;
+
while (true) {
if (!throtl_tg_can_downgrade(tg))
return false;
--
2.30.0