On Wed, 2016-04-27 at 10:07 +0800, Zhou Jie wrote:
> open_eth_start_xmit has a huge stack usage of 65536 bytes approx.
> Moving large arrays to heap to reduce stack usage.
>
> Signed-off-by: Zhou Jie <zhoujie2...@cn.fujitsu.com>
> ---
> hw/net/opencores_eth.c | 11 ++++++++++-
> 1 file changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/hw/net/opencores_eth.c b/hw/net/opencores_eth.c
> index c6094fb..fa0a4e7 100644
> --- a/hw/net/opencores_eth.c
> +++ b/hw/net/opencores_eth.c
> @@ -483,7 +483,8 @@ static NetClientInfo net_open_eth_info = {
>
> static void open_eth_start_xmit(OpenEthState *s, desc *tx)
> {
> - uint8_t buf[65536];
> + uint8_t *buf = NULL;
> + uint8_t buffer[0x600];
Hi,
I'm curious about 0x600.
How do you determine this size?
IMO, Max's suggestion looks more reasonable.
(1536 bytes, maximal frame length when HUGEN bit is not set in MODER)
Regards,
wei
> unsigned len = GET_FIELD(tx->len_flags, TXD_LEN);
> unsigned tx_len = len;
>
> @@ -498,6 +499,11 @@ static void open_eth_start_xmit(OpenEthState *s, desc
> *tx)
>
> trace_open_eth_start_xmit(tx->buf_ptr, len, tx_len);
>
> + if (tx_len > 0x600) {
> + buf = g_new(uint8_t, tx_len);
> + } else {
> + buf = buffer;
> + }
> if (len > tx_len) {
> len = tx_len;
> }
> @@ -506,6 +512,9 @@ static void open_eth_start_xmit(OpenEthState *s, desc *tx)
> memset(buf + len, 0, tx_len - len);
> }
> qemu_send_packet(qemu_get_queue(s->nic), buf, tx_len);
> + if (tx_len > 0x600) {
> + g_free(buf);
> + }
>
> if (tx->len_flags & TXD_WR) {
> s->tx_desc = 0;
