- Introduce ng_topo_mtx, a mutex to protect topology changes.
- In ng_destroy_node() protect with ng_topo_mtx the process
of checking and pointing at ng_deadnode. [1]
- In ng_con_part2() check that our peer is not a ng_deadnode,
and protect the check with ng_topo_mtx.
- Add KASSERTs to ng_acquire_read/write, to make more
understandible synopsis in case if called on ng_deadnode.
Reported by: Roselyn Lee [1]
- Introduce a new flags NGQF_QREADER and NGQF_QWRITER,
which tell how the item should be actually applied,
overriding NGQF_READER/NGQF_WRITER flags.
- Do not differ between pending reader or writer. Use only
one flag that is raised, when there are pending items.
- Schedule netgraph ISR in ng_queue_rw(), so that callers
do not need to do this job.
- Fix several comments.
Submitted by: julian
semantics, and then was reused for next node, it still would be applied
as writer again.
To fix the regression the decision is made never to alter item->el_flags
after the item has been allocated. This requires checking for overrides
both in ng_dequeue() and in ng_snd_item().
Details:
- Caller of the ng_apply_item() knows what is the current access to
node and specifies it to ng_apply_item(). The latter drops the
given access after item has beem applied.
- ng_dequeue() needs to be supplied with int pointer, where it stores
the obtained access on node.
- Check for node/hook access overrides in ng_dequeue().
times consequently, without checking whether callout has been serviced
or not. (ng_pptpgre and ng_ppp were catched in this behavior).
- In ng_callout() save old item before calling callout_reset(). If the
latter has returned 1, then free this item.
- In ng_uncallout() clear c->c_arg.
Problem reported by: Alexandre Kardanev
either reader or writer flag on item in the function, that
allocates the item. Do not modify these flags when item is
applied or queued.
The only exceptions are node and hook overrides - they can
change item flags to writer.
At the end of ng_snd_item(), node queue is processed. In certain
netgraph setups deep recursive calls can occur.
For example this happens, when two nodes are connected and can send
items to each other in both directions. If, for some reason, both nodes
have a lot of items in their queues, then the processing thread will
recurse between these two nodes, delivering items left and right, going
deeper in the stack. Other setups can suffer from deep recursion, too.
The following factors can influence risk of deep netgraph call:
- periodical write-access events on node
- combination of slow link and fast one in one graph
- net.inet.ip.fastforwarding
Changes made:
- In ng_acquire_{read,write}() do not dequeue another item. Instead,
call ng_setisr() for this node.
- At the end of ng_snd_item(), do not process queue. Call ng_setisr(),
if there are any dequeueable items on node queue.
- In ng_setisr() narrow worklist mutex holding.
- In ng_setisr() assert queue mutex.
Theoretically, the first two changes should negatively affect performance.
To check this, some profiling was made:
1) In general real tasks, no noticable performance difference was found.
2) The following test was made: two multithreaded nodes and one
single-threaded were connected into a ring. A large queues of packets
were sent around this ring. Time to pass the ring N times was measured.
This is a very vacuous test: no items/mbufs are allocated, no upcalls or
downcalls outside of netgraph. It doesn't represent a real load, it is
a stress test for ng_acquire_{read,write}() and item queueing functions.
Surprisingly, the performance impact was positive! New code is 13% faster
on UP and 17% faster on SMP, in this particular test.
The problem was originally found, described, analyzed and original patch
was written by Roselyn Lee from Vernier Networks. Thanks!
Submitted by: Roselyn Lee <rosel verniernetworks com>
an item may be queued and processed later. While this is OK for mbufs,
this is a problem for control messages.
In the framework:
- Add optional callback function pointer to an item. When item gets
applied the callback is executed from ng_apply_item().
- Add new flag NG_PROGRESS. If this flag is supplied, then return
EINPROGRESS instead of 0 in case if item failed to deliver
synchronously and was queued.
- Honor NG_PROGRESS in ng_snd_item().
In ng_socket:
- When userland sends control message add callback to the item.
- If ng_snd_item() returns EINPROGRESS, then sleep.
This change fixes possible races in ngctl(8) scripts.
Reviewed by: julian
Approved by: re (scottl)
specified by caller.
- Change ng_send_item() interface - use 'flags' argument instead of
boolean 'queue'.
- Extend ng_send_fn(), ng_package_data() and ng_package_msg()
interface - add possibility to pass flags. Rename ng_send_fn() to
ng_send_fn1(). Create macro for ng_send_fn().
- Update all macros, that use ng_package_data() and ng_package_msg().
Reviewed by: julian
SI_SUB_INIT_IF but before SI_SUB_DRIVERS. Make Netgraph(4)
framework initialize at SI_SUB_NETGRAPH level.
This does not address the bigger problem: MODULE_DEPEND
does not seem to work when modules are compiled in the
kernel, but it fixes the problem with Netgraph Bluetooth
device drivers reported by a few folks.
PR: i386/69876
Reviewed by: julian, rik, scottl
MFC after: 3 days
out c->c_func, we can't take it after callout_stop(). To take it before
we need to acquire callout_lock, to avoid race. This commit narrows
down area where lock is held, but hack is still present.
This should be redesigned.
Approved by: julian (mentor)
using linker_load_module(). This works OK if NGM_MKPEER message came
from userland and we have process associated with thread. But when
NGM_MKPEER was queued because target node was busy, linker_load_module()
is called from netisr thread leading to panic.
To workaround that we do not load modules by framework, instead ng_socket
loads module (if this is required) before sending NGM_MKPEER.
However, the race condition between return from NgSendMsg() and actual
creation of node still exist and needs to be solved.
PR: kern/62789
Approved by: julian
Also introduce a macro to be called by persistent nodes to signal their
persistence during shutdown to hide this mechanism from the node author.
Make node flags have a consistent style in naming.
Document the change.
is obviously not run a lot. (but is in some test cases).
This code is not usually run because it covers a case that doesn't
happen a lot (removing a node that has data traversing it).
for unknown events.
A number of modules return EINVAL in this instance, and I have left
those alone for now and instead taught MOD_QUIESCE to accept this
as "didn't do anything".
- Assert the mutex in NG_IDHASH_FIND() since the mutex is required to
safely walk the node lists in the ng_ID_hash table.
- Acquire the ng_nodelist_mtx when walking ng_allnodes or ng_allhooks
to generate state dump output from the netgraph sysctls.
behaviour lost in the change from 4.x style netgraph tee nodes.
Alter the tee node to use the new method. Document the behaviour.
Step the ABI version number... old netgraph klds will refuse to load.
Better than just crashing.
Submitted by: Gleb Smirnoff <glebius@cell.sick.ru>
whether or not the isr needs to hold Giant when running; Giant-less
operation is also controlled by the setting of debug_mpsafenet
o mark all netisr's except NETISR_IP as needing Giant
o add a GIANT_REQUIRED assertion to the top of netisr's that need Giant
o pickup Giant (when debug_mpsafenet is 1) inside ip_input before
calling up with a packet
o change netisr handling so swi_net runs w/o Giant; instead we grab
Giant before invoking handlers based on whether the handler needs Giant
o change netisr handling so that netisr's that are marked MPSAFE may
have multiple instances active at a time
o add netisr statistics for packets dropped because the isr is inactive
Supported by: FreeBSD Foundation
conservative lock. The problem with the lock-less algorithm is that
it suffers from the ABA problem. Running an application with funnels
a couple of 100kpkts/s through the netgraph system on a dual CPU system
with MPSAFE drivers will panic almost immediatly with the old algorithm.
It may be possible to eliminate the contention between threads that insert
free items into the list and those that get free items by using the
Michael/Scott queue algorithm that has two locks.
of asserting that an mbuf has a packet header. Use it instead of hand-
rolled versions wherever applicable.
Submitted by: Hiten Pandya <hiten@unixdaemons.com>
drain routines are done by swi_net, which allows for better queue control
at some future point. Packets may also be directly dispatched to a netisr
instead of queued, this may be of interest at some installations, but
currently defaults to off.
Reviewed by: hsu, silby, jayanth, sam
Sponsored by: DARPA, NAI Labs
queue items that can be allocated by netgraph and the number of free queue
items that are cached on a private list.
Netgraph places an upper limit on the number of queue items it may allocate.
When there is a large number of netgraph messages travelling through the
system (100k/sec and more) there is a high probability, that messages get
queued at the nodes and netgraph runs out of queue items. In this case the data
flow through netgraph gets blocked. The tuneable for the number of free
items lets one trade memory for performance.
The tunables are also available as read-only sysctls.
PR: kern/47393
Reviewed by: julian
Approved by: jake (mentor)
linker_load_module() instead.
This fixes a bug where the kernel was unable to properly locate and
load a kernel module in vfs_mount() (and probably in the netgraph
code as well since it was using the same function). This is because
the linker_load_file() does not properly search the module path.
Problem found by: peter
Reviewed by: peter
Thanks to: peter
most cases NULL is passed, but in some cases such as network driver locks
(which use the MTX_NETWORK_LOCK macro) and UMA zone locks, a name is used.
Tested on: i386, alpha, sparc64
Change a prototype.
Add a function version of ng_ref_node() when debugging so
a breakpoint can be set on it.
ng_base.c:
add 'node' as an argument to ng_apply_item so that it is up
to the caller to take over and release the item's reference on
the node. If the release reports back that the node went away
due to the reference going to 0, the caller should cease referencing
the now defunct node. (e.g. the item was a 'kill node' message).
Alter ng_unref_node to report back the residual references as a result.
ng_pptpgre.c:
Don't reference a node after we dropped a reference to it.
(What if it was the last?)
Fixes a node leak reported by Harti Brandt <brandt@fokus.gmd.de>
which was due to an incorrect earlier attempt to fix the
"accessing node after dropping the last reference" problem.
and add a sysctl to pppoe to activate non standard ethertypes
so that idiot ISPs (apparently in France) who use
equipment from idiot suppliers (rumour says 3com)
who use nonstandard ethertypes can still connect.
"yep, sure we do pppoe, we use a different identifier to that dictated in
the standard, but sure it's pppoe!"
sysctl -w net.graph.stupid_isp=1 enables the changeover.
mtx_enter(lock, type) becomes:
mtx_lock(lock) for sleep locks (MTX_DEF-initialized locks)
mtx_lock_spin(lock) for spin locks (MTX_SPIN-initialized)
similarily, for releasing a lock, we now have:
mtx_unlock(lock) for MTX_DEF and mtx_unlock_spin(lock) for MTX_SPIN.
We change the caller interface for the two different types of locks
because the semantics are entirely different for each case, and this
makes it explicitly clear and, at the same time, it rids us of the
extra `type' argument.
The enter->lock and exit->unlock change has been made with the idea
that we're "locking data" and not "entering locked code" in mind.
Further, remove all additional "flags" previously passed to the
lock acquire/release routines with the exception of two:
MTX_QUIET and MTX_NOSWITCH
The functionality of these flags is preserved and they can be passed
to the lock/unlock routines by calling the corresponding wrappers:
mtx_{lock, unlock}_flags(lock, flag(s)) and
mtx_{lock, unlock}_spin_flags(lock, flag(s)) for MTX_DEF and MTX_SPIN
locks, respectively.
Re-inline some lock acq/rel code; in the sleep lock case, we only
inline the _obtain_lock()s in order to ensure that the inlined code
fits into a cache line. In the spin lock case, we inline recursion and
actually only perform a function call if we need to spin. This change
has been made with the idea that we generally tend to avoid spin locks
and that also the spin locks that we do have and are heavily used
(i.e. sched_lock) do recurse, and therefore in an effort to reduce
function call overhead for some architectures (such as alpha), we
inline recursion for this case.
Create a new malloc type for the witness code and retire from using
the M_DEV type. The new type is called M_WITNESS and is only declared
if WITNESS is enabled.
Begin cleaning up some machdep/mutex.h code - specifically updated the
"optimized" inlined code in alpha/mutex.h and wrote MTX_LOCK_SPIN
and MTX_UNLOCK_SPIN asm macros for the i386/mutex.h as we presently
need those.
Finally, caught up to the interface changes in all sys code.
Contributors: jake, jhb, jasone (in no particular order)
also try implement teh documented behaviour in socket nodes
so that when there is only one hook, an unaddressed write/send
will DTRT and send the data to that hook.
(e.g. ethernet nodes are persistent until you rip out the hardware)
Use this support in the ethernet and sample nodes.
Add some more abstraction on the 'item's so that node and
hook reference counting can be checked easier.
Slight man page correction.
Make pppoe type dependent on ethernet type.
Clean up node shutdown a little.
Move a mutex from MTX_SPIN to MTX_DEF (oops)
Fix small ref-counting bug.
remove warning on one2many type.
from a node, but does it via the locking queue, thus ensuring that the
node is locked when it's hook is removed.
Add 'deadnode' and 'deadhook' structures for when a node or hook is
invalidated but not yet freed. (not yet freed)
This version is functional and is aproaching solid..
notice I said APROACHING. There are many node types I cannot test
I have tested: echo hole ppp socket vjc iface tee bpf async tty
The rest compile and "Look" right. More changes to follow.
DEBUGGING is enabled in this code to help if people have problems.
format version number. (userland programs should not need to be
recompiled when the netgraph kernel internal ABI is changed.
Also fix modules that don;t handle the fact that a caller may not supply
a return message pointer. (benign at the moment because the calling code
checks, but that will change)
This clears out my outstanding netgraph changes.
There is a netgraph change of design in the offing and this is to some
extent a superset of soem of the new functionality and some of the old
functionality that may be removed.
This code works as before, but allows some new features that I want to
work with and evaluate. It is the basis for a version of netgraph
with integral locking for SMP use.
This is running on my test machine with no new problems :-)
NGM_BINARY2ASCII, which convert control messages to ASCII and back.
This allows control messages to be sent and received in ASCII form
using ngctl(8), which makes ngctl a lot more useful.
This also allows all the type-specific debugging code in libnetgraph
to go away -- instead, we just ask the node itself to do the ASCII
translation for us.
Currently, all generic control messages are supported, as well as
messages associated with the following node types: async, cisco,
ksocket, and ppp.
See /usr/share/examples/netgraph/ngctl for an example of using this.
Also give ngctl(8) the ability to print out incoming data and
control messages at any time. Eventually nghook(8) may be subsumed.
Several other misc. bug fixes.
Reviewed by: julian
parameter a char ** instead of a const char **. This make these
kernel routines consistent with the corresponding libc userland
routines.
Which is actually 'correct' is debatable, but consistency and
following the spec was deemed more important in this case.
Reviewed by (in concept): phk, bde
Been in production for 3 years now. Gives Instant Frame relay to if_sr
and if_ar drivers, and PPPOE support soon. See:
ftp://ftp.whistle.com/pub/archie/netgraph/index.html
for on-line manual pages.
Reviewed by: Doug Rabson (dfr@freebsd.org)
Obtained from: Whistle CVS tree
