On Thu, Jan 18 2018 at 10:09pm -0500,
Joseph Qi <joseph.qi@xxxxxxxxxxxxxxxxx> wrote:
> From: Joseph Qi <joseph.qi@xxxxxxxxxxxxxxxxx>
>
> DM device sets QUEUE_FLAG_NONROT after the queue is registered. 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.
>
> Signed-off-by: Joseph Qi <joseph.qi@xxxxxxxxxxxxxxxxx>
> Reviewed-by: Shaohua Li <shli@xxxxxxxxxx>
> ---
> block/blk-throttle.c | 19 +++++++++++++++++++
> 1 file changed, 19 insertions(+)
>
> diff --git a/block/blk-throttle.c b/block/blk-throttle.c
> index bf52035..7150f14 100644
> --- a/block/blk-throttle.c
> +++ b/block/blk-throttle.c
> @@ -541,6 +541,25 @@ 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;
> +
> +#ifdef CONFIG_BLK_DEV_THROTTLING_LOW
> + /*
> + * DM device sets QUEUE_FLAG_NONROT after the queue is registered,
> + * so the previous initialization is wrong in this case. Check and
> + * update it here.
> + */
> + if (blk_queue_nonrot(blkg->q) &&
> + td->filtered_latency != LATENCY_FILTERED_SSD) {
> + int i;
> +
> + td->throtl_slice = DFL_THROTL_SLICE_SSD;
> + td->filtered_latency = LATENCY_FILTERED_SSD;
> + for (i = 0; i < LATENCY_BUCKET_SIZE; i++) {
> + td->avg_buckets[READ][i].latency = 0;
> + td->avg_buckets[WRITE][i].latency = 0;
> + }
> + }
> +#endif
> }
>
> /*
> --
> 1.9.4
This should be fixed for 4.16, please see these block tree commits:
http://git.kernel.dk/cgit/linux-block/commit/?h=for-4.16/block&id=fa70d2e2c4a0a54ced98260c6a176cc94c876d27
http://git.kernel.dk/cgit/linux-block/commit/?h=for-4.16/block&id=c100ec49fdd2222836ff8a17c7bfcc7611d2ee2b
The last commit's patch header even references the previous submission
you had for this patch with:
"These changes also stave off the need to introduce new DM-specific
workarounds in block core, e.g. this proposal:
https://patchwork.kernel.org/patch/10067961/";
