| Message ID | 1318937995-14228-1-git-send-email-peppe.cavallaro@st.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
Le mardi 18 octobre 2011 à 13:39 +0200, Giuseppe CAVALLARO a écrit : > Problem using big mtu around 4096 bytes is you end allocating (4096 > +NET_SKB_PAD + NET_IP_ALIGN + sizeof(struct skb_shared_info) bytes -> > 8192 bytes : order-1 pages > > It's better to limit the mtu to SKB_MAX_HEAD(NET_SKB_PAD), > to have no more than one page per skb. > > Also the patch changes the netdev_alloc_skb_ip_align() done in > init_dma_desc_rings() and uses a variant allowing GFP_KERNEL allocations > allowing the driver to load even in case of memory pressure. > > Reported-by: Eric Dumazet <eric.dumazet@gmail.com> > Signed-off-by: Giuseppe Cavallaro <peppe.cavallaro@st.com> > --- > drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 6 ++++-- > 1 files changed, 4 insertions(+), 2 deletions(-) > Seems good, thanks :) Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c index 1848a16..6b8f455 100644 --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c @@ -474,11 +474,13 @@ static void init_dma_desc_rings(struct net_device *dev) for (i = 0; i < rxsize; i++) { struct dma_desc *p = priv->dma_rx + i; - skb = netdev_alloc_skb_ip_align(dev, bfsize); + skb = __netdev_alloc_skb(dev, bfsize + NET_IP_ALIGN, + GFP_KERNEL); if (unlikely(skb == NULL)) { pr_err("%s: Rx init fails; skb is NULL\n", __func__); break; } + skb_reserve(skb, NET_IP_ALIGN); priv->rx_skbuff[i] = skb; priv->rx_skbuff_dma[i] = dma_map_single(priv->device, skb->data, bfsize, DMA_FROM_DEVICE); @@ -1401,7 +1403,7 @@ static int stmmac_change_mtu(struct net_device *dev, int new_mtu) if (priv->plat->enh_desc) max_mtu = JUMBO_LEN; else - max_mtu = BUF_SIZE_4KiB; + max_mtu = SKB_MAX_HEAD(NET_SKB_PAD + NET_IP_ALIGN); if ((new_mtu < 46) || (new_mtu > max_mtu)) { pr_err("%s: invalid MTU, max MTU is: %d\n", dev->name, max_mtu);
Problem using big mtu around 4096 bytes is you end allocating (4096 +NET_SKB_PAD + NET_IP_ALIGN + sizeof(struct skb_shared_info) bytes -> 8192 bytes : order-1 pages It's better to limit the mtu to SKB_MAX_HEAD(NET_SKB_PAD), to have no more than one page per skb. Also the patch changes the netdev_alloc_skb_ip_align() done in init_dma_desc_rings() and uses a variant allowing GFP_KERNEL allocations allowing the driver to load even in case of memory pressure. Reported-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: Giuseppe Cavallaro <peppe.cavallaro@st.com> --- drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 6 ++++-- 1 files changed, 4 insertions(+), 2 deletions(-)