From c7669f50121ac43d33fe8fe7c38f737c6c35e323 Mon Sep 17 00:00:00 2001 From: John Garry Date: Wed, 29 May 2019 17:58:44 +0800 Subject: [PATCH] scsi: hisi_sas: Reduce HISI_SAS_SGE_PAGE_CNT in size 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 Signed-off-by: John Garry Signed-off-by: Martin K. Petersen --- 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); -- 2.45.2