RFC patch: https://lkml.org/lkml/2021/9/9/1432 There is a proformance problem in our environment: A host can provide a remote device to difierent client. If one client is under high io pressure, other clients might be affected. Limit the overall iops/bps(io.max) from the client can fix the problem, however, config files do not exist in root cgroup currently, which makes it impossible. This patch enables io throttle for root cgroup: - enable "io.max" and "io.low" in root - don't skip root group in tg_iops_limit() and tg_bps_limit() - don't skip root group in tg_conf_updated() Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx> --- block/blk-throttle.c | 13 ++----------- 1 file changed, 2 insertions(+), 11 deletions(-) diff --git a/block/blk-throttle.c b/block/blk-throttle.c index 7c462c006b26..ac25bfbbfe7f 100644 --- a/block/blk-throttle.c +++ b/block/blk-throttle.c @@ -156,9 +156,6 @@ 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) { @@ -186,9 +183,6 @@ 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) { @@ -1284,9 +1278,8 @@ static void tg_conf_updated(struct throtl_grp *tg, bool global) struct throtl_grp *parent_tg; tg_update_has_rules(this_tg); - /* ignore root/second level */ - if (!cgroup_subsys_on_dfl(io_cgrp_subsys) || !blkg->parent || - !blkg->parent->parent) + /* ignore root level */ + if (!cgroup_subsys_on_dfl(io_cgrp_subsys) || !blkg->parent) continue; parent_tg = blkg_to_tg(blkg->parent); /* @@ -1625,7 +1618,6 @@ static struct cftype throtl_files[] = { #ifdef CONFIG_BLK_DEV_THROTTLING_LOW { .name = "low", - .flags = CFTYPE_NOT_ON_ROOT, .seq_show = tg_print_limit, .write = tg_set_limit, .private = LIMIT_LOW, @@ -1633,7 +1625,6 @@ static struct cftype throtl_files[] = { #endif { .name = "max", - .flags = CFTYPE_NOT_ON_ROOT, .seq_show = tg_print_limit, .write = tg_set_limit, .private = LIMIT_MAX, -- 2.31.1
