diff mbox series

[3/6] scsi: hisi_sas: Reduce HISI_SAS_SGE_PAGE_CNT in size

Message ID 1559123927-160502-4-git-send-email-john.garry@huawei.com
State Accepted
Commit c7669f50121ac43d33fe8fe7c38f737c6c35e323
Headers show
Series hisi_sas: Some misc patches | expand

Commit Message

John Garry May 29, 2019, 9:58 a.m. UTC 
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>

---
 drivers/scsi/hisi_sas/hisi_sas.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

-- 
2.17.1
diff mbox series

Patch

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);