path MTU discovery and the tcp_minmss limiter for very small MTU's.
When the MTU suggested by the gateway via ICMP, or if there isn't
any the next smaller step from ip_next_mtu(), is lower than the
floor enforced by net.inet.tcp.minmss (default 216) the value is
ignored and the default MSS (512) is used instead. However the
DF flag in the IP header is still set in tcp_output() preventing
fragmentation by the gateway.
Fix this by using tcp_minmss as the MSS and clear the DF flag if
the suggested MTU is too low. This turns off path MTU dissovery
for the remainder of the session and allows fragmentation to be
done by the gateway.
Only MTU's smaller than 256 are affected. The smallest official
MTU specified is for AX.25 packet radio at 256 octets.
PR: kern/146628
Tested by: Matthew Luckie <mjl-at-luckie org nz>
MFC after: 1 week
report when a new socket couldn't be created because one of
in_pcbinshash(), in6_pcbconnect() or in_pcbconnect() failed.
Logging is conditional on net.inet.tcp.log_debug being enabled.
MFC after: 1 week
and we loop back to 'again'. If the remainder is less or equal
to one full segment, the TSO flag was not cleared even though
it isn't necessary anymore. Enabling the TSO flag on a segment
that doesn't require any offloaded segmentation by the NIC may
cause confusion in the driver or hardware.
Reset the internal tso flag in tcp_output() on every iteration
of sendalot.
PR: kern/132832
Submitted by: Renaud Lienhart <renaud-at-vmware com>
MFC after: 1 week
a kernel printf to a log output with the priority of LOG_NOTICE.
This way the messages still show up in /var/log/messages but no
longer spam the console every other second on busy servers that
are port scanned:
"Limiting open port RST response from 114 to 100 packets/sec"
PR: kern/147352
Submitted by: Eugene Grosbein <eugen-at-eg sd rdtc ru>
MFC after: 1 week
It was experimental and interferes with the normal congestion control
algorithms by instating a separate, possibly lower, ceiling for the
amount of data that is in flight to the remote host. With high speed
internet connections the inflight limit frequently has been estimated
too low due to the noisy nature of the RTT measurements.
This code gives way for the upcoming pluggable congestion control
framework. It is the task of the congestion control algorithm to
set the congestion window and amount of inflight data without external
interference.
Reviewed by: lstewart
MFC after: 1 week
Removal after: 1 month
and go to the next iteration early if multicast filtering would decide that
this socket shall not receive the data.
Unlock the pcb in that case or we leak the read lock and next time trying
to get a write lock, would hang forever.
PR: kern/149608
Submitted by: Chris Luke (chrisy flirble.org)
MFC after: 3 days
It is more appropriate in this context because TSC MSR is reset to zero
when the CPU is restarted from S3 and above. Move acpi_resync_clock() back
to where it was before r211202. It does not make a difference any more.
Interrupt driven configuration hooks serve two purposes: they are a
mechanism for registering for a callback that is invoked once interrupt
services are available, and they hold off root device selection so long
as any configuration hooks are still active. Before this change, it was
not possible to safely register additional hooks from the context of a
configuration hook callback. The need for this feature arises when
interrupts are required to discover new devices (e.g. access to the XenStore
to find para-virtualized devices) which in turn also require the ability
to hold off root device selection until some lengthy, interrupt driven,
configuration task has completed (e.g. Xen front/back device driver
negotiation).
More specifically, the mutex protecting the list of active configuration
hooks is never held during a callback, and static information is used
to ensure proper ordering and only a single callback to each hook even
when faced with registration or removal of a hook during an active run.
Sponsored by: Spectra Logic Corporation
MFC after: 1 week.
time-of-day clock or vice versa. For x86 systems, RTC resolution is one
second and we used to lose up to one second whenever we initialize system
time from RTC or write system time back to RTC. With this change, margin
of error per conversion is roughly between -0.5 and +0.5 second rather
than between -1 and 0 second. Note that it does not take care of errors
from getnanotime(9) (which is up to 1/hz second) or CLOCK_GETTIME() latency.
These are just too expensive to correct and it is not worthy of the cost.
case future compile-time knobs were added that it wants to use.
Also add include guards and forward declarations to vm/memguard.h.
Approved by: zml (mentor)
MFC after: 1 month
if the device file appears during or after the link creation.
User created symbolic links are now inserted at the head of the
directory entry list after the "." and ".." entries. A new directory
entry flag DE_COVERED indicates that an entry is covered by a symbolic
link.
PR: kern/114057
Reviewed by: kib
Idea from: kib
Discussed on: freebsd-current (mostly silence)
As long as interrupts are disabled and there is not explicit call to
sched_add() there can't be any preemption there, thus the calls may be
consistent.
Reported by: kib, jhb
- Enable KX and UX bits on CPU startup for non-boot CPUs
- Keep the KX bit when in userspace - XTLB handler needs it to access
PCPU data
- revert r210638 partly - we don't need to enable KX on kernel entry
now
Reviewed by: jmallett, imp
1. Move dirty bit emulation code that is duplicted for kernel and user
in trap.c to a function pmap_emulate_modified() in pmap.c.
2. While doing dirty bit emulation, it is not necessary to update the
TLB entry on all CPUs using smp_rendezvous(), we can just update the
TLB entry on the current CPU, and let the other CPUs update their TLB
entry lazily if they get an exception.
Reviewed by: alc, neel
per-cpu variants are also available to be called. The per-cpu variants
are needed for some later optimizations.
Also remove unnecessary casts, do some style fixes.
Reviewed by: alc, neel
bufobj lock. If b_bufobj is not NULL, then bufobj lock should be
held when manipulating the flags. Not doing this sometimes leaves
BV_BKGRDINPROG to be erronously set, causing softdep' getdirtybuf() to
stuck indefinitely in "getbuf" sleep, waiting for background write to
finish which is not actually performed.
Add BO_LOCK() in the cases where it was missed.
In collaboration with: pho
Tested by: bz
Reviewed by: jeff
MFC after: 1 month
the worklist (in softdep_process_journal), but also after flushing the
workitems. Might be, we should even do this before bwillwrite() too, but
this seems to be not needed for now.
Fs might be suspended during processing the queue, and then there is
nobody around to unsuspend.
In collaboration with: pho
Tested by: bz
Reviewed by: jeff
If it does, don't then try reprogramming the NF "cap" values (ie
what values are the "maximum" value the NF can be) - instead,
just leave the current CCA value as the NF cap.
This was inspired by some similar work from ath9k. It isn't
a 100% complete solution (as there may be some reason where a
high NF CCA/cap is written, causing the baseband to stop thinking it
is able to transmit, leading to stuck beacon and interface reset)
which I'll investigate and look at fixing in a later commit.
Obtained from: Linux
AR5416 and later chipsets.
ath_hal_calibrateN() calls the HAL calibrateN function with rxchainmask=0x1.
This is not necessarily the case for AR5416 and later chipsets.
use-after-free over a longer time. Also release the backing pages of
a guarded allocation at free(9) time to reduce the overhead of using
memguard(9). Allow setting and varying the malloc type at run-time.
Add knobs to allow:
- randomly guarding memory
- adding un-backed KVA guard pages to detect underflow and overflow
- a lower limit on the size of allocations that are guarded
Reviewed by: alc
Reviewed by: brueffer, Ulrich Spörlein <uqs spoerlein net> (man page)
Silence from: -arch
Approved by: zml (mentor)
MFC after: 1 month
