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SubjectRe: [PATCH v5 08/10] scsi: ufshpb: Limit the number of inflight map requests
On 2021-03-02 21:25, Avri Altman wrote:
> in host control mode the host is the originator of map requests. To not

in -> In

Thanks,
Can Guo.

> flood the device with map requests, use a simple throttling mechanism
> that limits the number of inflight map requests.
>
> Signed-off-by: Avri Altman <avri.altman@wdc.com>
> ---
> drivers/scsi/ufs/ufshpb.c | 11 +++++++++++
> drivers/scsi/ufs/ufshpb.h | 1 +
> 2 files changed, 12 insertions(+)
>
> diff --git a/drivers/scsi/ufs/ufshpb.c b/drivers/scsi/ufs/ufshpb.c
> index 89a930e72cff..74da69727340 100644
> --- a/drivers/scsi/ufs/ufshpb.c
> +++ b/drivers/scsi/ufs/ufshpb.c
> @@ -21,6 +21,7 @@
> #define READ_TO_MS 1000
> #define READ_TO_EXPIRIES 100
> #define POLLING_INTERVAL_MS 200
> +#define THROTTLE_MAP_REQ_DEFAULT 1
>
> /* memory management */
> static struct kmem_cache *ufshpb_mctx_cache;
> @@ -750,6 +751,14 @@ static struct ufshpb_req
> *ufshpb_get_map_req(struct ufshpb_lu *hpb,
> struct ufshpb_req *map_req;
> struct bio *bio;
>
> + if (hpb->is_hcm &&
> + hpb->num_inflight_map_req >= THROTTLE_MAP_REQ_DEFAULT) {
> + dev_info(&hpb->sdev_ufs_lu->sdev_dev,
> + "map_req throttle. inflight %d throttle %d",
> + hpb->num_inflight_map_req, THROTTLE_MAP_REQ_DEFAULT);
> + return NULL;
> + }
> +
> map_req = ufshpb_get_req(hpb, srgn->rgn_idx, REQ_OP_SCSI_IN);
> if (!map_req)
> return NULL;
> @@ -764,6 +773,7 @@ static struct ufshpb_req
> *ufshpb_get_map_req(struct ufshpb_lu *hpb,
>
> map_req->rb.srgn_idx = srgn->srgn_idx;
> map_req->rb.mctx = srgn->mctx;
> + hpb->num_inflight_map_req++;
>
> return map_req;
> }
> @@ -773,6 +783,7 @@ static void ufshpb_put_map_req(struct ufshpb_lu
> *hpb,
> {
> bio_put(map_req->bio);
> ufshpb_put_req(hpb, map_req);
> + hpb->num_inflight_map_req--;
> }
>
> static int ufshpb_clear_dirty_bitmap(struct ufshpb_lu *hpb,
> diff --git a/drivers/scsi/ufs/ufshpb.h b/drivers/scsi/ufs/ufshpb.h
> index b49e9a34267f..d83ab488688a 100644
> --- a/drivers/scsi/ufs/ufshpb.h
> +++ b/drivers/scsi/ufs/ufshpb.h
> @@ -212,6 +212,7 @@ struct ufshpb_lu {
> struct ufshpb_req *pre_req;
> int num_inflight_pre_req;
> int throttle_pre_req;
> + int num_inflight_map_req;
> struct list_head lh_pre_req_free;
> int cur_read_id;
> int pre_req_min_tr_len;

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