From: John Garry <john.garry@huawei.com>
Date: Wed, 29 May 2019 17:58:44 +0800
Subject: scsi: hisi_sas: Reduce HISI_SAS_SGE_PAGE_CNT in size
Patch-mainline: v5.3-rc1
Git-commit: c7669f50121ac43d33fe8fe7c38f737c6c35e323
References: bsc#1137322 bsc#1137323 bsc#1138099 bsc#1138100
Macro HISI_SAS_SGE_PAGE_CNT is defined to SG_CHUNK_SIZE, which is 128.
This means that sizeof(struct hisi_sas_slot_buf_table) is 4192. This is
just over a 4K, which can mean inefficient DMA memory usage (for no PI).
Reduce the size of HISI_SAS_SGE_PAGE_CNT to 124 to fit in a 4K page. With
this change, we experience no performance hit.
Cc: dann frazier <dann.frazier@canonical.com>
Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Daniel Wagner <dwagner@suse.de>
---
drivers/scsi/hisi_sas/hisi_sas.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/scsi/hisi_sas/hisi_sas.h b/drivers/scsi/hisi_sas/hisi_sas.h
index fc87994b5d73..06f22fb372b1 100644
--- a/drivers/scsi/hisi_sas/hisi_sas.h
+++ b/drivers/scsi/hisi_sas/hisi_sas.h
@@ -484,12 +484,12 @@ struct hisi_sas_command_table_stp {
u8 atapi_cdb[ATAPI_CDB_LEN];
};
-#define HISI_SAS_SGE_PAGE_CNT SG_CHUNK_SIZE
+#define HISI_SAS_SGE_PAGE_CNT (124)
struct hisi_sas_sge_page {
struct hisi_sas_sge sge[HISI_SAS_SGE_PAGE_CNT];
} __aligned(16);
-#define HISI_SAS_SGE_DIF_PAGE_CNT SG_CHUNK_SIZE
+#define HISI_SAS_SGE_DIF_PAGE_CNT HISI_SAS_SGE_PAGE_CNT
struct hisi_sas_sge_dif_page {
struct hisi_sas_sge sge[HISI_SAS_SGE_DIF_PAGE_CNT];
} __aligned(16);
--
2.16.4