Thanks for working on this. But it seems that this patch
completely breaks build without dpdk. There are a lot of places
where dpdk functions in use regardless of define DPDK_NETDEV.
Beside that I see that you're allocating new mbufs inside generic
dp_packet_* functions. But, in context of non-PMD threads this
must be under 'non_pmd_mutex'. Otherwise, mempool could be corrupted.
Best regards, Ilya Maximets.
On 16.05.2018 20:32, Tiago Lam wrote:
> This patchset introduces support for multi-segment mbufs to OvS-DPDK.
> Multi-segment mbufs are typically used when the size of an mbuf is
> insufficient to contain the entirety of a packet's data. Instead, the
> data is split across numerous mbufs, each carrying a portion, or
> 'segment', of the packet data. mbufs are chained via their 'next'
> attribute (an mbuf pointer).
> Use Cases
> i. Handling oversized (guest-originated) frames, which are marked
> for hardware accelration/offload (TSO, for example).
> Packets which originate from a non-DPDK source may be marked for
> offload; as such, they may be larger than the permitted ingress
> interface's MTU, and may be stored in an oversized dp-packet. In
> order to transmit such packets over a DPDK port, their contents
> must be copied to a DPDK mbuf (via dpdk_do_tx_copy). However, in
> its current implementation, that function only copies data into
> a single mbuf; if the space available in the mbuf is exhausted,
> but not all packet data has been copied, then it is lost.
> Similarly, when cloning a DPDK mbuf, it must be considered
> whether that mbuf contains multiple segments. Both issues are
> resolved within this patchset.
> ii. Handling jumbo frames.
> While OvS already supports jumbo frames, it does so by increasing
> mbuf size, such that the entirety of a jumbo frame may be handled
> in a single mbuf. This is certainly the preferred, and most
> performant approach (and remains the default). However, it places
> high demands on system memory; multi-segment mbufs may be
> prefereable for systems which are memory-constrained.
> Enabling multi-segment mbufs
> Multi-segment and single-segment mbufs are mutually exclusive, and the
> user must decide on which approach to adopt on init. The introduction
> of a new OVSDB field, 'dpdk-multi-seg-mbufs', facilitates this.
> This is a global boolean value, which determines how jumbo frames are
> represented across all DPDK ports. In the absence of a user-supplied
> value, 'dpdk-multi-seg-mbufs' defaults to false, i.e. multi-segment
> mbufs must be explicitly enabled / single-segment mbufs remain the
> Setting the field is identical to setting existing DPDK-specific OVSDB
> ovs-vsctl set Open_vSwitch . other_config:dpdk-init=true
> ovs-vsctl set Open_vSwitch . other_config:dpdk-lcore-mask=0x10
> ovs-vsctl set Open_vSwitch . other_config:dpdk-socket-mem=4096,0
> ==> ovs-vsctl set Open_vSwitch . other_config:dpdk-multi-seg-mbufs=true
> v6: - Rebase on master 7c0cb29 ("conntrack-tcp: Handle tcp session
> - Further improve dp_packet_put_uninit() and dp_packet_shift() to
> support multi-seg mbufs;
> - Add support for multi-seg mbufs in dp_packet_l4_size() and
> improve other helper funcs, such as dp_packet_tail() and dp_
> - Add support for multi-seg mbufs in dp_packet_put(), dp_packet_
> put_zeros(), as well as dp_packet_resize__() - allocating new
> mbufs and linking them together;
> Restructured patchset:
> - Squash patch 5 into patch 6, since they were both related to
> copying data while handling multi-seg mbufs;
> - Split patch 4 into two separate patches - one that introduces the
> changes in helper functions to deal with multi-seg mbufs and
> two others for the shift() and put_uninit() functionality;
> - Move patch 4 to before patch 3, so that ihelper functions come
> before functionality improvement that rely on those helpers.
> v5: - Rebased on master e5e22dc ("datapath-windows: Prevent ct-counters
> from getting redundantly incremented");
> - Sugesh's comments have been addressed:
> - Changed dp_packet_set_data() and dp_packet_set_size() logic to
> make them independent of each other;
> - Dropped patch 3 now that dp_packet_set_data() and dp_packet_set_
> size() are independent;
> - dp_packet_clone_with_headroom() now has split functions for
> handling DPDK sourced packets and non-DPDK packets;
> - Modified various functions in dp-packet.h to account for multi-seg
> mbufs - dp_packet_put_uninit(), dp_packet_tail(), dp_packet_tail()
> and dp_packet_at();
> - Added support for shifting packet data in multi-seg mbufs, using
> - Fixed some minor inconsistencies.
> Note that some of the changes in v5 have been contributed by Mark
> Kavanagh as well.
> v4: - restructure patchset
> - account for 128B ARM cacheline when sizing mbufs
> Mark Kavanagh (4):
> netdev-dpdk: fix mbuf sizing
> dp-packet: Init specific mbuf fields.
> netdev-dpdk: copy large packet to multi-seg. mbufs
> netdev-dpdk: support multi-segment jumbo frames
> Michael Qiu (1):
> dp-packet: copy data from multi-seg. DPDK mbuf
> Tiago Lam (6):
> dp-packet: Fix allocated size on DPDK init.
> dp-packet: Fix data_len handling multi-seg mbufs.
> dp-packet: Handle multi-seg mbufs in helper funcs.
> dp-packet: Handle multi-seg mbufs in put*() funcs.
> dp-packet: Handle multi-seg mubfs in shift() func.
> dp-packet: Handle multi-seg mbufs in resize__().
> NEWS | 1 +
> lib/dp-packet.c | 347
> lib/dp-packet.h | 317 ++++++++++++++++++++++++++++++++++++----------
> lib/dpdk.c | 7 ++
> lib/netdev-dpdk.c | 177 +++++++++++++++++++++-----
> lib/netdev-dpdk.h | 3 +-
> vswitchd/vswitch.xml | 20 +++
> 7 files changed, 745 insertions(+), 127 deletions(-)
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