Since the e1000 DMA engines hava no constraints on the alignment of buffer
transfers, there is no reason to tell busdma that there is. This save a
minimum of 1 malloc call per packet, which translates to eliminating 4 locks.
It also means that buffers are not needlessly bounced when transfered. The
end result is a 38% improvement in pps in a 4 way bridging environment.
Obtained from: Sandvine, Inc.
(usually taking 20 seconds to transmit a packet).. no longer fall back
to only transmitting one packet (instead of the entire queue) after we
have processed the entire send queue... I have no idea why we didn't
start seeing this problem ~6 years ago when this code was introduced...
(sorele()/sotryfree()):
- This permits the caller to acquire the accept mutex before the socket
mutex, avoiding sofree() having to drop the socket mutex and re-order,
which could lead to races permitting more than one thread to enter
sofree() after a socket is ready to be free'd.
- This also covers clearing of the so_pcb weak socket reference from
the protocol to the socket, preventing races in clearing and
evaluation of the reference such that sofree() might be called more
than once on the same socket.
This appears to close a race I was able to easily trigger by repeatedly
opening and resetting TCP connections to a host, in which the
tcp_close() code called as a result of the RST raced with the close()
of the accepted socket in the user process resulting in simultaneous
attempts to de-allocate the same socket. The new locking increases
the overhead for operations that may potentially free the socket, so we
will want to revise the synchronization strategy here as we normalize
the reference counting model for sockets. The use of the accept mutex
in freeing of sockets that are not listen sockets is primarily
motivated by the potential need to remove the socket from the
incomplete connection queue on its parent (listen) socket, so cleaning
up the reference model here may allow us to substantially weaken the
synchronization requirements.
RELENG_5_3 candidate.
MFC after: 3 days
Reviewed by: dwhite
Discussed with: gnn, dwhite, green
Reported by: Marc UBM Bocklet <ubm at u-boot-man dot de>
Reported by: Vlad <marchenko at gmail dot com>
modes on a tty structure.
Both the ".init" and the current settings are initialized allowing
the function to be used both at attach and open time.
The function takes an argument to decide if echoing should be enabled.
Echoing should not be enabled for regular physical serial ports
unless they are consoles, in which case they should be configured
by ttyconsolemode() instead.
Use the new function throughout.
the implementation of the following feature in revision 1.4:
- Install Makefile.yp as /var/yp/Makefile.dist and link it to
/var/yp/Makefile only if /var/yp/Makefile doesn't already exist.
Suggested by Peter Wemm.
The actual code was only symlinking when no /var/yp/Makefile.dist
existed, i.e., never.
List of functional changes:
- Make a single device per single node with a single hook.
This gives us parrallelizm, which can't be achieved on a single
node with many devices/hooks. This also gives us flexibility - we
can play with a particular device node, not affecting others.
- Remove read queue as it is. Use struct ifqueue instead. This change
removes a lot of extra memcpy()ing, m_devget()ting and m_copymem()ming.
In ng_device_receivedata() we enqueue an mbuf and wake readers.
In ngdread() we take one mbuf from qeueue and uiomove() it to
userspace. If no mbuf is present we optionally block. [1]
- In ngdwrite() we create an mbuf from uio using m_uiotombuf().
This is faster then uiomove() into buffer, and then m_copydata(),
and this is much better than huge m_pullup().
- Perform locking of device
- Perform locking of connection list.
- Clear out _rcvmsg method, since it does nothing good yet.
- Implement NGM_DEVICE_GET_DEVNAME message.
- #if 0 ioctl method, while nothing is done here yet.
- Return immediately from ngdwrite() if uio_resid == 0.
List of tidyness changes:
- Introduce device2priv(), to remove cut'n'paste.
- Use MALLOC/FREE, instead of malloc/free.
- Use unit2minor().
- Use UID_ROOT/GID_WHEEL instead of 0/0.
- Define NGD_DEVICE_DEVNAME, use it.
- Use more nice macros for debugging. [2]
- Return Exxx, not -1.
style(9) changes:
- No "#endif" after short block.
- Break long lines.
- Remove extra spaces, add needed spaces.
[1] Obtained from: if_tun.c
[2] Obtained from: ng_pppoe.c
Reviewed by: marks
Approved by: julian (mentor)
MFC after: 1 month
1. Conform to IEEE Std 1003.1-2004, which state that "Constructed
arguments cannot grow larger than 255 bytes", and
2. Avoid a buffer overflow.
Unfortunately the standard doesn't indicate how xargs is supposed to
handle arguments which (with the appropriate substitutions) would grow
larger than 255 bytes; this solution handles those by making as many
substitutions as possible without overflowing the buffer.
OpenBSD's xargs resolves this in a different direction, by making
all the substitutions and then silently truncating the resulting string.
Since this change may break existing scripts which rely upon the buffer
overflow (255 bytes isn't really all that long...) it will not be MFCed.
failure in the NFS server would result in a leaked instance of the NFS
server subsystem lock. Liberally sprinkle assertions in all target
labels for error unwinding to assert the desired locking state.
RELENG_5_3 candidate.
MFC after: 3 days
Reported by: Wilkinson, Alex <alex dot wilkinson at dsto dot defence dot gov dot au>
errors are in rarely executed paths.
1. Each time the retry_alloc path is taken, the PG_BUSY must be set again.
Otherwise vm_page_remove() panics.
2. There is no need to set PG_BUSY on the newly allocated page before
freeing it. The page already has PG_BUSY set by vm_page_alloc().
Setting it again could cause an assertion failure.
MFC after: 2 weeks
probably means it also requires a .so version
bump. Defer it until I finish some related
work on cleaning up error returns throughout
the library.
Thanks to: Conrad J. Sabatier
Current or prospective timestamps: Georgia, Uruguay, Argentina, and Brazil
Historial timestamps and/or commentary: Malaysia, Mongolia, Singapore,
Peru, Russua, Israel, United States, Canada
Changes in Argentina and Brazil have created several new time zone regions.
Users are encouraged to rerun tzsetup(8), even if current times appear
correct, to ensure that future times will be interepreted correctly.
Obtained from: Arthur Olson, ftp://elsie.nci.nih.gov/pub/tzdata2004e.tar.gz
