Re: [RFC-v3 9/9] iser-target: Add iSCSI Extensions for RDMA (iSER) target driver

Or Gerlitz
2013-04-04T09:46:07Z

On 04/04/2013 10:24, Nicholas A. Bellinger wrote:

> +#define ISER_RECV_DATA_SEG_LEN 8192
> +#define ISER_RX_PAYLOAD_SIZE (ISER_HEADERS_LEN + ISER_RECV_DATA_SEG_LEN)
> [...]
> +#define ISER_RX_PAD_SIZE (16384 - (ISER_RX_PAYLOAD_SIZE + \
> + sizeof(u64) + sizeof(struct ib_sge)))

We're eating here too much ram for the pad, you need 8K + something, so
the pad can count down
from 12K and not 16K which means each such element will consume three
pages and not four.

> +struct iser_rx_desc {
> + struct iser_hdr iser_header;
> + struct iscsi_hdr iscsi_header;
> + char data[ISER_RECV_DATA_SEG_LEN];
> + u64 dma_addr;
> + struct ib_sge rx_sg;
> + char pad[ISER_RX_PAD_SIZE];
> +} __packed;
> +
> +struct isert_rx_desc {
> + struct isert_conn *desc_conn;
> + struct work_struct desc_work;
> + struct iser_rx_desc desc;
> +} __packed;

You have way enough room in the pad field of struct iser_rx_desc to
place there the two fields
added by struct isert_rx_desc (and you only use struct iser_rx_desc from
within isert_rx_desc) --> any reason
not to unify them?

Or.