In an attempt to avoid having to allocate memory on the send path, the netvsc driver was requesting additional head room so that both rndis header and the netvsc packet (the state that had to persist) could be placed in the skb. Since the amount of head room requested was exceeding the default head room as set in LL_MAX_HEADER, we were forcing a reallocation of skb. With this patch-set, I have reduced the size of the netvsc packet to less than 20 bytes and with this reduction we don't need to ask for any additional headroom. We place the rndis header in the skb head room and we place the netvsc packet in control buffer area in the skb. V2: - Addressed review comments: - Eliminated more fields from netvsc packet structure. V3: - Fixed a typo in patch: hv_netvsc: Don't ask for additional head room in the skb. K. Y. Srinivasan (15): hv_netvsc: Resize some of the variables in hv_netvsc_packet hv_netvsc: Rearrange the hv_negtvsc_packet to be space efficient hv_netvsc: Eliminate the channel field in hv_netvsc_packet structure hv_netvsc: Eliminate rndis_msg pointer from hv_netvsc_packet structure hv_netvsc: Eliminatte the data field from struct hv_netvsc_packet hv_netvsc: Eliminate send_completion from struct hv_netvsc_packet hv_netvsc: Eliminate send_completion_ctx from struct hv_netvsc_packet hv_netvsc: Don't ask for additional head room in the skb hv_netvsc: Eliminate page_buf from struct hv_netvsc_packet hv_netvsc: Eliminate send_completion_tid from struct hv_netvsc_packet hv_netvsc: Eliminate is_data_pkt from struct hv_netvsc_packet hv_netvsc: Eliminate completion_func from struct hv_netvsc_packet hv_netvsc: Eliminate xmit_more from struct hv_netvsc_packet hv_netvsc: Eliminate status from struct hv_netvsc_packet hv_netvsc: Eliminate vlan_tci from struct hv_netvsc_packet Vitaly Kuznetsov (2): hv_netvsc: move subchannel existence check to netvsc_select_queue() hv_netvsc: remove locking in netvsc_send() drivers/net/hyperv/hyperv_net.h | 48 +++++++---------- drivers/net/hyperv/netvsc.c | 102 ++++++++++++++++++------------------- drivers/net/hyperv/netvsc_drv.c | 93 +++++++++++++--------------------- drivers/net/hyperv/rndis_filter.c | 66 ++++++++++++------------ include/linux/netdevice.h | 4 +- 5 files changed, 138 insertions(+), 175 deletions(-) -- 1.7.4.1 _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel