Quoted from comment in throtl_pd_init: "If on the default hierarchy, we
switch to properly hierarchical behavior where limits on a given
throtl_grp are applied to the whole subtree rather than just the group
itself. e.g. If 16M read_bps limit is set on the root group, the whole
system can' exceed 16M for the device."
Commit b22c417c885ea9 ("blk-throttle: configure bps/iops limit for
cgroup in low limit") broke this rule and did not explain why.
Restore the ability to limit the whole system by root group.
Signed-off-by: Kemeng Shi <shikemeng@xxxxxxxxxx>
---
block/blk-throttle.c | 6 ------
1 file changed, 6 deletions(-)
diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index 847721dc2b2b..96aa53e30e28 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -150,9 +150,6 @@ static uint64_t tg_bps_limit(struct throtl_grp *tg, int rw)
struct throtl_data *td;
uint64_t ret;
- if (cgroup_subsys_on_dfl(io_cgrp_subsys) && !blkg->parent)
- return U64_MAX;
-
td = tg->td;
ret = tg->bps[rw][td->limit_index];
if (ret == 0 && td->limit_index == LIMIT_LOW) {
@@ -180,9 +177,6 @@ static unsigned int tg_iops_limit(struct throtl_grp *tg, int rw)
struct throtl_data *td;
unsigned int ret;
- if (cgroup_subsys_on_dfl(io_cgrp_subsys) && !blkg->parent)
- return UINT_MAX;
-
td = tg->td;
ret = tg->iops[rw][td->limit_index];
if (ret == 0 && tg->td->limit_index == LIMIT_LOW) {
--
2.30.0
