| Message ID | 1365099482-30287-1-git-send-email-roland@kernel.org (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
> >From: Roland Dreier <roland@purestorage.com> > >Markus Stockhausen <markus.stockhausen@gmx.de> noticed that IPoIB was >spending significant time doing memcpy() in __pskb_pull_tail(). He >found that this is because his adapter reports a maximum MTU of 4K, >which causes IPoIB datagram mode to receive all the actual data in a >separate page in the fragment list. > >We're already allocating extra tailroom for the skb linear part, so we >might as well use it. > >Cc: Eric Dumazet <edumazet@google.com> >Reported-by: Markus Stockhausen <markus.stockhausen@gmx.de> >Signed-off-by: Roland Dreier <roland@purestorage.com> >--- > drivers/infiniband/ulp/ipoib/ipoib.h | 3 ++- > drivers/infiniband/ulp/ipoib/ipoib_ib.c | 12 +++--------- > 2 files changed, 5 insertions(+), 10 deletions(-) > >diff --git a/drivers/infiniband/ulp/ipoib/ipoib.h >b/drivers/infiniband/ulp/ipoib/ipoib.h >index eb71aaa..ab2cc4c 100644 >--- a/drivers/infiniband/ulp/ipoib/ipoib.h >+++ b/drivers/infiniband/ulp/ipoib/ipoib.h >@@ -64,7 +64,8 @@ enum ipoib_flush_level { > enum { > IPOIB_ENCAP_LEN = 4, > >- IPOIB_UD_HEAD_SIZE = IB_GRH_BYTES + IPOIB_ENCAP_LEN, >+ /* add 128 bytes of tailroom for IP/TCP headers */ >+ IPOIB_UD_HEAD_SIZE = IB_GRH_BYTES + IPOIB_ENCAP_LEN + 128, >... Thanks for the help but I guess the patch is not yet perfect. My (remote) test machine stopped responding after loading the new ipoib module. Tomorrow I can check the console. Having a look at the source code I guess we now have some major problems when receiving small packets: ... ipoib_ud_skb_put_frags(..., unsigned int length) ... size = length - IPOIB_UD_HEAD_SIZE; /* may be less than zero! */ skb_frag_size_set(frag, size); ... Markus -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" 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/infiniband/ulp/ipoib/ipoib.h b/drivers/infiniband/ulp/ipoib/ipoib.h index eb71aaa..ab2cc4c 100644 --- a/drivers/infiniband/ulp/ipoib/ipoib.h +++ b/drivers/infiniband/ulp/ipoib/ipoib.h @@ -64,7 +64,8 @@ enum ipoib_flush_level { enum { IPOIB_ENCAP_LEN = 4, - IPOIB_UD_HEAD_SIZE = IB_GRH_BYTES + IPOIB_ENCAP_LEN, + /* add 128 bytes of tailroom for IP/TCP headers */ + IPOIB_UD_HEAD_SIZE = IB_GRH_BYTES + IPOIB_ENCAP_LEN + 128, IPOIB_UD_RX_SG = 2, /* max buffer needed for 4K mtu */ IPOIB_CM_MTU = 0x10000 - 0x10, /* padding to align header to 16 */ diff --git a/drivers/infiniband/ulp/ipoib/ipoib_ib.c b/drivers/infiniband/ulp/ipoib/ipoib_ib.c index 2cfa76f..9eaa58e 100644 --- a/drivers/infiniband/ulp/ipoib/ipoib_ib.c +++ b/drivers/infiniband/ulp/ipoib/ipoib_ib.c @@ -156,18 +156,12 @@ static struct sk_buff *ipoib_alloc_rx_skb(struct net_device *dev, int id) struct ipoib_dev_priv *priv = netdev_priv(dev); struct sk_buff *skb; int buf_size; - int tailroom; u64 *mapping; - if (ipoib_ud_need_sg(priv->max_ib_mtu)) { - buf_size = IPOIB_UD_HEAD_SIZE; - tailroom = 128; /* reserve some tailroom for IP/TCP headers */ - } else { - buf_size = IPOIB_UD_BUF_SIZE(priv->max_ib_mtu); - tailroom = 0; - } + buf_size = ipoib_ud_need_sg(priv->max_ib_mtu) ? + IPOIB_UD_HEAD_SIZE : IPOIB_UD_BUF_SIZE(priv->max_ib_mtu); - skb = dev_alloc_skb(buf_size + tailroom + 4); + skb = dev_alloc_skb(buf_size + 4); if (unlikely(!skb)) return NULL;