diff mbox series

[v2,01/10] blk-throttle: correct stale comment in throtl_pd_init

Message ID 20221129030147.27400-2-shikemeng@huawei.com (mailing list archive)
State New, archived
Headers show
Series A few bugfix and cleanup patches for blk-throttle | expand

Commit Message

Kemeng Shi Nov. 29, 2022, 3:01 a.m. UTC
On the default hierarchy (cgroup2), the throttle interface files don't
exist in the root cgroup, so the ablity to limit the whole system
by configuring root group is not existing anymore. In general, cgroup
doesn't wanna be in the business of restricting resources at the
system level, so correct the stale comment that we can limit whole
system to we can only limit subtree.

Signed-off-by: Kemeng Shi <shikemeng@huawei.com>
---
 block/blk-throttle.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

Comments

Tejun Heo Nov. 30, 2022, 9:08 p.m. UTC | #1
On Tue, Nov 29, 2022 at 11:01:38AM +0800, Kemeng Shi wrote:
> On the default hierarchy (cgroup2), the throttle interface files don't
> exist in the root cgroup, so the ablity to limit the whole system
> by configuring root group is not existing anymore. In general, cgroup
> doesn't wanna be in the business of restricting resources at the
> system level, so correct the stale comment that we can limit whole
> system to we can only limit subtree.
> 
> Signed-off-by: Kemeng Shi <shikemeng@huawei.com>

Acked-by: Tejun Heo <tj@kernel.org>

> +	 * read_bps limit is set on a "parent" group, summary bps of
> +	 * "parent" group and its subtree groups can't exceed 16M for the

but why the quotes around parent?
diff mbox series

Patch

diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index 847721dc2b2b..59acfac87764 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -395,8 +395,9 @@  static void throtl_pd_init(struct blkg_policy_data *pd)
 	 * 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't
-	 * exceed 16M for the device.
+	 * read_bps limit is set on a "parent" group, summary bps of
+	 * "parent" group and its subtree groups can't exceed 16M for the
+	 * device.
 	 *
 	 * If not on the default hierarchy, the broken flat hierarchy
 	 * behavior is retained where all throtl_grps are treated as if