commands can be written to /dev/psm%d and status can be read back from it.
- Reflect the change in psm(4) and bump version for ports.
MFC after: 1 week
buffer kernel descriptors, which is used to allow the buffer
currently in the BPF "store" position to be assigned to userspace
when it fills, even if userspace hasn't acknowledged the buffer
in the "hold" position yet. To implement this, notify the buffer
model when a buffer becomes full, and check that the store buffer
is writable, not just for it being full, before trying to append
new packet data. Shared memory buffers will be assigned to
userspace at most once per fill, be it in the store or in the
hold position.
This removes the restriction that at most one shared memory can
by owned by userspace, reducing the chances that userspace will
need to call select() after acknowledging one buffer in order to
wait for the next buffer when under high load. This more fully
realizes the goal of zero system calls in order to process a
high-speed packet stream from BPF.
Update bpf.4 to reflect that both buffers may be owned by userspace
at once; caution against assuming this.
overhead of packet capture by allowing a user process to directly "loan"
buffer memory to the kernel rather than using read(2) to explicitly copy
data from kernel address space.
The user process will issue new BPF ioctls to set the shared memory
buffer mode and provide pointers to buffers and their size. The kernel
then wires and maps the pages into kernel address space using sf_buf(9),
which on supporting architectures will use the direct map region. The
current "buffered" access mode remains the default, and support for
zero-copy buffers must, for the time being, be explicitly enabled using
a sysctl for the kernel to accept requests to use it.
The kernel and user process synchronize use of the buffers with atomic
operations, avoiding the need for system calls under load; the user
process may use select()/poll()/kqueue() to manage blocking while
waiting for network data if the user process is able to consume data
faster than the kernel generates it. Patchs to libpcap are available
to allow libpcap applications to transparently take advantage of this
support. Detailed information on the new API may be found in bpf(4),
including specific atomic operations and memory barriers required to
synchronize buffer use safely.
These changes modify the base BPF implementation to (roughly) abstrac
the current buffer model, allowing the new shared memory model to be
added, and add new monitoring statistics for netstat to print. The
implementation, with the exception of some monitoring hanges that break
the netstat monitoring ABI for BPF, will be MFC'd.
Zerocopy bpf buffers are still considered experimental are disabled
by default. To experiment with this new facility, adjust the
net.bpf.zerocopy_enable sysctl variable to 1.
Changes to libpcap will be made available as a patch for the time being,
and further refinements to the implementation are expected.
Sponsored by: Seccuris Inc.
In collaboration with: rwatson
Tested by: pwood, gallatin
MFC after: 4 months [1]
[1] Certain portions will probably not be MFCed, specifically things
that can break the monitoring ABI.
The logical disks will appear as /dev/lvm/<vol group>-<logical vol>, for
instance /dev/lvm/vg0-home. G_LINUX_LVM currently supports linear stripes with
segments on multiple physical disks. The metadata is read only, logical
volumes can not be allocated or resized.
Reviewed by: Ivan Voras
Previously known as geom_lvm(4), rename requested by des, phk.
- mention LRO support
- describe multi-slice related tunables.
- correct DIAGNOSTICS section to reflect that missing firmware
is non-fatal.
Submitted by: gallatin
The logical disks will appear as /dev/lvm/<vol group>-<logical vol>, for
instance /dev/lvm/vg0-home. GLVM currently supports linear stripes with
segments on multiple physical disks. The metadata is read only, logical
volumes can not be allocated or resized.
Reviewed by: Ivan Voras
NOP-message polling in ciss_periodic().
Note that setting the tunable to non-zero can be workaround only for
`ADAPTER HEARTBEAT FAILED' problem, and may freeze the system w/o
the problem.
Reviewed by: scottl
Reported by: Attila Nagy
MFC after: 3 days
