| Message ID | 20221123060401.20392-10-shikemeng@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | A few bugfix and cleanup patches for blk-throttle | expand |
On Wed, Nov 23, 2022 at 02:03:59PM +0800, Kemeng Shi wrote: > We always keep limit index valid as following: > Max limit is always valid and low limit can only be invalidated in > blk_throtl_update_limit_valid. Each time low limit may become invalid > after blk_throtl_update_limit_valid is called, we will check and make > sure current limit index is valid. > > It's reasonable to always keep limit index valid, so we can remove this > check. It's not obvious to me that it's correct and I'm not sure what we're gaining by removing this while risking subtle breakages.
on 11/24/2022 2:31 AM, Tejun Heo wrote: > On Wed, Nov 23, 2022 at 02:03:59PM +0800, Kemeng Shi wrote: >> We always keep limit index valid as following: >> Max limit is always valid and low limit can only be invalidated in >> blk_throtl_update_limit_valid. Each time low limit may become invalid >> after blk_throtl_update_limit_valid is called, we will check and make >> sure current limit index is valid. >> >> It's reasonable to always keep limit index valid, so we can remove this >> check. > > It's not obvious to me that it's correct and I'm not sure what we're gaining > by removing this while risking subtle breakages. I will remove this patch in next version.
diff --git a/block/blk-throttle.c b/block/blk-throttle.c index 3eccc7af4368..6f509cadd92b 100644 --- a/block/blk-throttle.c +++ b/block/blk-throttle.c @@ -418,12 +418,10 @@ static void tg_update_has_rules(struct throtl_grp *tg) for (rw = READ; rw <= WRITE; rw++) { tg->has_rules_iops[rw] = (parent_tg && parent_tg->has_rules_iops[rw]) || - (td->limit_valid[td->limit_index] && - tg_iops_limit(tg, rw) != UINT_MAX); + (tg_iops_limit(tg, rw) != UINT_MAX); tg->has_rules_bps[rw] = (parent_tg && parent_tg->has_rules_bps[rw]) || - (td->limit_valid[td->limit_index] && - (tg_bps_limit(tg, rw) != U64_MAX)); + (tg_bps_limit(tg, rw) != U64_MAX); } }
We always keep limit index valid as following: Max limit is always valid and low limit can only be invalidated in blk_throtl_update_limit_valid. Each time low limit may become invalid after blk_throtl_update_limit_valid is called, we will check and make sure current limit index is valid. It's reasonable to always keep limit index valid, so we can remove this check. Signed-off-by: Kemeng Shi <shikemeng@huawei.com> --- block/blk-throttle.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-)