From: Can Guo <cang@codeaurora.org>
To: Avri Altman <avri.altman@wdc.com>
Cc: "James E . J . Bottomley" <jejb@linux.vnet.ibm.com>,
"Martin K . Petersen" <martin.petersen@oracle.com>,
linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org,
gregkh@linuxfoundation.org, Bart Van Assche <bvanassche@acm.org>,
yongmyung lee <ymhungry.lee@samsung.com>,
Daejun Park <daejun7.park@samsung.com>,
alim.akhtar@samsung.com, asutoshd@codeaurora.org,
Zang Leigang <zangleigang@hisilicon.com>,
Avi Shchislowski <avi.shchislowski@wdc.com>,
Bean Huo <beanhuo@micron.com>,
stanley.chu@mediatek.com
Subject: Re: [PATCH v6 04/10] scsi: ufshpb: Make eviction depends on region's reads
Date: Thu, 25 Mar 2021 13:34:21 +0800 [thread overview]
Message-ID: <b06c0bcc3ea51ab7d6b8e5fb46ed6bdb@codeaurora.org> (raw)
In-Reply-To: <20210322081044.62003-5-avri.altman@wdc.com>
On 2021-03-22 16:10, Avri Altman wrote:
> In host mode, eviction is considered an extreme measure.
> verify that the entering region has enough reads, and the exiting
> region has much less reads.
>
> Signed-off-by: Avri Altman <avri.altman@wdc.com>
> ---
> drivers/scsi/ufs/ufshpb.c | 18 +++++++++++++++++-
> 1 file changed, 17 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/scsi/ufs/ufshpb.c b/drivers/scsi/ufs/ufshpb.c
> index a1519cbb4ce0..5e757220d66a 100644
> --- a/drivers/scsi/ufs/ufshpb.c
> +++ b/drivers/scsi/ufs/ufshpb.c
> @@ -17,6 +17,7 @@
> #include "../sd.h"
>
> #define ACTIVATION_THRESHOLD 8 /* 8 IOs */
> +#define EVICTION_THRESHOLD (ACTIVATION_THRESHOLD << 5) /* 256 IOs */
>
> /* memory management */
> static struct kmem_cache *ufshpb_mctx_cache;
> @@ -1047,6 +1048,13 @@ static struct ufshpb_region
> *ufshpb_victim_lru_info(struct ufshpb_lu *hpb)
> if (ufshpb_check_srgns_issue_state(hpb, rgn))
> continue;
>
> + /*
> + * in host control mode, verify that the exiting region
> + * has less reads
> + */
> + if (hpb->is_hcm && rgn->reads > (EVICTION_THRESHOLD >> 1))
> + continue;
> +
> victim_rgn = rgn;
> break;
> }
> @@ -1219,7 +1227,7 @@ static int ufshpb_issue_map_req(struct ufshpb_lu
> *hpb,
>
> static int ufshpb_add_region(struct ufshpb_lu *hpb, struct
> ufshpb_region *rgn)
> {
> - struct ufshpb_region *victim_rgn;
> + struct ufshpb_region *victim_rgn = NULL;
> struct victim_select_info *lru_info = &hpb->lru_info;
> unsigned long flags;
> int ret = 0;
> @@ -1246,7 +1254,15 @@ static int ufshpb_add_region(struct ufshpb_lu
> *hpb, struct ufshpb_region *rgn)
> * It is okay to evict the least recently used region,
> * because the device could detect this region
> * by not issuing HPB_READ
> + *
> + * in host control mode, verify that the entering
> + * region has enough reads
> */
> + if (hpb->is_hcm && rgn->reads < EVICTION_THRESHOLD) {
> + ret = -EACCES;
> + goto out;
> + }
> +
I cannot understand the logic behind this. A rgn which host chooses to
activate,
is in INACTIVE state now, if its rgn->reads < 256, then don't activate
it.
Could you please elaborate?
Thanks,
Can Guo.
> victim_rgn = ufshpb_victim_lru_info(hpb);
> if (!victim_rgn) {
> dev_warn(&hpb->sdev_ufs_lu->sdev_dev,
next prev parent reply other threads:[~2021-03-25 5:36 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-22 8:10 [PATCH v6 00/10] Add Host control mode to HPB Avri Altman
2021-03-22 8:10 ` [PATCH v6 01/10] scsi: ufshpb: Cache HPB Control mode on init Avri Altman
2021-03-22 8:10 ` [PATCH v6 02/10] scsi: ufshpb: Add host control mode support to rsp_upiu Avri Altman
2021-03-24 3:31 ` Zang Leigang
2021-03-24 3:59 ` Can Guo
2021-03-24 12:44 ` Avri Altman
2021-03-22 8:10 ` [PATCH v6 03/10] scsi: ufshpb: Add region's reads counter Avri Altman
2021-03-24 9:25 ` Can Guo
2021-03-24 11:28 ` Avri Altman
2021-03-27 8:02 ` Avri Altman
2021-03-22 8:10 ` [PATCH v6 04/10] scsi: ufshpb: Make eviction depends on region's reads Avri Altman
2021-03-25 5:34 ` Can Guo [this message]
2021-03-25 5:56 ` Avri Altman
2021-03-22 8:10 ` [PATCH v6 05/10] scsi: ufshpb: Region inactivation in host mode Avri Altman
2021-03-22 8:10 ` [PATCH v6 06/10] scsi: ufshpb: Add hpb dev reset response Avri Altman
2021-03-22 8:10 ` [PATCH v6 07/10] scsi: ufshpb: Add "Cold" regions timer Avri Altman
2021-03-22 8:10 ` [PATCH v6 08/10] scsi: ufshpb: Limit the number of inflight map requests Avri Altman
2021-03-22 8:10 ` [PATCH v6 09/10] scsi: ufshpb: Add support for host control mode Avri Altman
2021-03-22 8:10 ` [PATCH v6 10/10] scsi: ufshpb: Make host mode parameters configurable Avri Altman
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