Removed dead code that assumed that M_TRYWAIT can return NULL; it's not true
since the advent of MBUMA.
Reviewed by: arch
There are ongoing disputes as to whether we want to switch to directly using
UMA flags M_WAITOK/M_NOWAIT for mbuf(9) allocation.
details from consumers.
- Track individual selecters on a per-descriptor basis such that there
are no longer collisions and after sleeping for events only those
descriptors which triggered events must be rescaned.
- Protect the selinfo (per descriptor) structure with a mtx pool mutex.
mtx pool mutexes were chosen to preserve api compatibility with
existing code which does nothing but bzero() to setup selinfo
structures.
- Use a per-thread wait channel rather than a global wait channel.
- Hide select implementation details in a seltd structure which is
opaque to the rest of the kernel.
- Provide a 'selsocket' interface for those kernel consumers who wish to
select on a socket when they have no fd so they no longer have to
be aware of select implementation details.
Tested by: kris
Reviewed on: arch
- Use thread_lock() rather than sched_lock for per-thread scheduling
sychronization.
- Use the per-process spinlock rather than the sched_lock for per-process
scheduling synchronization.
Tested by: kris, current@
Tested on: i386, amd64, ULE, 4BSD, libthr, libkse, PREEMPTION, etc.
Discussed with: kris, attilio, kmacy, jhb, julian, bde (small parts each)
We have to adjust curthread's state enough so that it appears to be
in a poll(2) or select(2) call so that selrecord() will work and then
teardown that state after calling sopoll().
- Fix some minor nits in nearby ncp_sock_rselect() and in the identical
nbssn_rselect() function in the netsmb code:
- Don't call nb_poll()/ncp_poll() now that ncp_poll() already fakes up
poll(2) state since the rselect() functions already do that. Just
invoke sopoll() directly.
- To make things slightly more intuitive, store the results of sopoll()
in a new 'revents' variable rather than 'error' since that's what
sopoll() actually returns.
- If the requested timeout time has been exceeded by the time we get
ready to block, then return EWOULDBLOCK rather than 0 to signal a
timeout as this is what the calling code expects.
Tested by: Eric Christeson <eric.j.christeson AT gmail> (1)
MFC after: 1 week
soreceive(), and sopoll(), which are wrappers for pru_sosend,
pru_soreceive, and pru_sopoll, and are now used univerally by socket
consumers rather than either directly invoking the old so*() functions
or directly invoking the protocol switch method (about an even split
prior to this commit).
This completes an architectural change that was begun in 1996 to permit
protocols to provide substitute implementations, as now used by UDP.
Consumers now uniformly invoke sosend(), soreceive(), and sopoll() to
perform these operations on sockets -- in particular, distributed file
systems and socket system calls.
Architectural head nod: sam, gnn, wollman
o Add a mutex (sb_mtx) to struct sockbuf. This protects the data in a
socket buffer. The mutex in the receive buffer also protects the data
in struct socket.
o Determine the lock strategy for each members in struct socket.
o Lock down the following members:
- so_count
- so_options
- so_linger
- so_state
o Remove *_locked() socket APIs. Make the following socket APIs
touching the members above now require a locked socket:
- sodisconnect()
- soisconnected()
- soisconnecting()
- soisdisconnected()
- soisdisconnecting()
- sofree()
- soref()
- sorele()
- sorwakeup()
- sotryfree()
- sowakeup()
- sowwakeup()
Reviewed by: alfred
- Since polling should not involve sleeping, keep holding a
process lock upon scanning file descriptors.
- Hold a reference to every file descriptor prior to entering
polling loop in order to avoid lock order reversal between
lockmgr and p_mtx upon calling fdrop() in fo_poll().
(NOTE: this work has not been done for netncp and netsmb
yet because a socket itself has no reference counts.)
Reviewed by: jhb
Use mchain API to work with mbuf chains.
Do not depend on INET and IPX options.
Allocate ncp_rq structure dynamically to prevent possible stack overflows.
Let ncp_request() dispose control structure if request failed.
Move all NCP wrappers to ncp_ncp.c file and all NCP request processing
functions to ncp_rq.c file.
Improve reconnection logic.
Misc style fixes.
This is because calls with M_WAIT (now M_TRYWAIT) may not wait
forever when nothing is available for allocation, and may end up
returning NULL. Hopefully we now communicate more of the right thing
to developers and make it very clear that it's necessary to check whether
calls with M_(TRY)WAIT also resulted in a failed allocation.
M_TRYWAIT basically means "try harder, block if necessary, but don't
necessarily wait forever." The time spent blocking is tunable with
the kern.ipc.mbuf_wait sysctl.
M_WAIT is now deprecated but still defined for the next little while.
* Fix a typo in a comment in mbuf.h
* Fix some code that was actually passing the mbuf subsystem's M_WAIT to
malloc(). Made it pass M_WAITOK instead. If we were ever to redefine the
value of the M_WAIT flag, this could have became a big problem.
