Hi Mike, On 17/11/21 05:02, Mike Snitzer wrote: > On Sun, Nov 19, 2017 at 9:00 PM, Joseph Qi <jiangqi903@xxxxxxxxx> wrote: >> From: Joseph Qi <qijiang.qj@xxxxxxxxxxxxxxx> >> >> dm device set QUEUE_FLAG_NONROT in resume, which is after register >> queue. That is to mean, the previous initialization in >> blk_throtl_register_queue is wrong in this case. >> Fix it by checking and then updating the info during root tg >> initialization as we don't have a better choice. > > Given DM motivated this change, curious why you didn't send this to dm-devel? > Since this is io.low specifically, I don't want the change in device mapper layer. But I do agree with you that I have to cc dm-devel as well. Sorry for missing that. > In any case, not sure why you need to reference "resume". Very few > people will appreciate that detail. > > Better to just say: DM device sets QUEUE_FLAG_NONROT after the queue > is registered. > Thanks for your advice. I will update and resend it. Thanks, Joseph >> Signed-off-by: Joseph Qi <qijiang.qj@xxxxxxxxxxxxxxx> >> --- >> block/blk-throttle.c | 17 +++++++++++++++++ >> 1 file changed, 17 insertions(+) >> >> diff --git a/block/blk-throttle.c b/block/blk-throttle.c >> index bf52035..6d6b220 100644 >> --- a/block/blk-throttle.c >> +++ b/block/blk-throttle.c >> @@ -541,6 +541,23 @@ static void throtl_pd_init(struct blkg_policy_data *pd) >> if (cgroup_subsys_on_dfl(io_cgrp_subsys) && blkg->parent) >> sq->parent_sq = &blkg_to_tg(blkg->parent)->service_queue; >> tg->td = td; >> + >> + /* >> + * dm device set QUEUE_FLAG_NONROT in resume, which is after resister >> + * queue, so the previous initialization is wrong in this case. Check >> + * and update it here. >> + */ > > typo: s/resister/register/ > But again, best to say: > DM device sets QUEUE_FLAG_NONROT after the queue is registered, ... > > Also, an alternative to your patch would be to have DM's > dm_table_set_restrictions() call a blk-throttle function to setup > blk-throttle after it is done setting queue flags? > Saves all other drivers from having to run this 2 stage initialization > code.. just a thought. > > Mike >
