Commit 6c59cb50 authored by Avri Altman's avatar Avri Altman Committed by Martin K. Petersen
Browse files

scsi: ufs: ufshpb: Make eviction depend on region's reads 

In host mode, eviction is considered an extreme measure. Verify that the
entering region has enough reads, and the exiting region has fewer reads.

Link: https://lore.kernel.org/r/20210712095039.8093-6-avri.altman@wdc.com


Reviewed-by: default avatarDaejun Park <daejun7.park@samsung.com>
Signed-off-by: default avatarAvri Altman <avri.altman@wdc.com>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent c76a1888

drivers/scsi/ufs/ufshpb.c

+17 −1
Original line number Diff line number Diff line
@@ -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;
@@ -1056,6 +1057,13 @@ 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 fewer reads

		 */

		if (hpb->is_hcm && rgn->reads > (EVICTION_THRESHOLD >> 1))

			continue;



		victim_rgn = rgn;

		break;

	}
@@ -1223,7 +1231,7 @@ 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;
@@ -1250,7 +1258,15 @@ 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;

			}



			victim_rgn = ufshpb_victim_lru_info(hpb);

			if (!victim_rgn) {

				dev_warn(&hpb->sdev_ufs_lu->sdev_dev,