implementation.
The kernel RPC code, which is responsible for the low-level scheduling
of incoming NFS requests, contains a throttling mechanism that
prevents too much kernel memory from being tied up by NFS requests
that are being serviced. When the throttle is engaged, the RPC layer
stops servicing incoming NFS sockets, resulting ultimately in
backpressure on the clients (if they're using TCP). However, this is
a very heavy-handed mechanism as it prevents all clients from making
any requests, regardless of how heavy or light they are. (Thus, when
engaged, the throttle often prevents clients from even mounting the
filesystem.) The throttle mechanism applies specifically to requests
that have been received by the RPC layer (from a TCP or UDP socket)
and are queued waiting to be serviced by one of the nfsd threads; it
does not limit the amount of backlog in the socket buffers.
The original implementation limited the total bytes of queued requests
to the minimum of a quarter of (nmbclusters * MCLBYTES) and 45 MiB.
The former limit seems reasonable, since requests queued in the socket
buffers and replies being constructed to the requests in progress will
all require some amount of network memory, but the 45 MiB limit is
plainly ridiculous for modern memory sizes: when running 256 service
threads on a busy server, 45 MiB would result in just a single
maximum-sized NFS3PROC_WRITE queued per thread before throttling.
Removing this limit exposed integer-overflow bugs in the original
computation, and related bugs in the routines that actually account
for the amount of traffic enqueued for service threads. The old
implementation also attempted to reduce accounting overhead by
batching updates until each queue is fully drained, but this is prone
to livelock, resulting in repeated accumulate-throttle-drain cycles on
a busy server. Various data types are changed to long or unsigned
long; explicit 64-bit types are not used due to the unavailability of
64-bit atomics on many 32-bit platforms, but those platforms also
cannot support nmbclusters large enough to cause overflow.
This code (in a 10.1 kernel) is presently running on production NFS
servers at CSAIL.
Summary of this revision:
* Removes 45 MiB limit on requests queued for nfsd service threads
* Fixes integer-overflow and signedness bugs
* Avoids unnecessary throttling by not deferring accounting for
completed requests
Differential Revision: https://reviews.freebsd.org/D2165
Reviewed by: rmacklem, mav
MFC after: 30 days
Relnotes: yes
Sponsored by: MIT Computer Science & Artificial Intelligence Laboratory
%rdi, %rsi, etc are inadvertently bypassed along with the check to
see if the instruction needs to be repeated per the 'rep' prefix.
Add "MOVS" instruction support for the 'MMIO to MMIO' case.
Reviewed by: neel
specially aml8726-m6 and aml8726-m8b SoC based devices.
aml8726-m6 SoC exist in devices such as Visson ATV-102.
Hardkernel ODROID-C1 board has aml8726-m8b SoC.
The following support is included:
Basic machdep code
SMP
Interrupt controller
Clock control driver (aka gate)
Pinctrl
Timer
Real time clock
UART
GPIO
I2C
SD controller
SDXC controller
USB
Watchdog
Random number generator
PLL / Clock frequency measurement
Frame buffer
Submitted by: John Wehle
Approved by: stas (mentor)
on Intel processors. Clear spurious dependency by explicitely xoring
the destination register of popcnt.
Use bitcount64() instead of re-implementing SWAR locally, for
processors without popcnt instruction.
Reviewed by: jhb
Discussed with: jilles (previous version)
Sponsored by: The FreeBSD Foundation
rather than 20. The MP 1.4 specification states in Appendix B.2:
"A period of 20 microseconds should be sufficient for IPI dispatch to
complete under normal operating conditions".
(Note that this appears to be separate from the 10 millisecond (INIT) and
200 microsecond (STARTUP) waits after the IPIs are dispatched.) The
Intel SDM is silent on this issue as far as I can tell.
At least some hardware requires 60 microseconds as noted in the PR, so
bump this to 100 to be on the safe side.
PR: 197756
Reported by: zaphod@berentweb.com
MFC after: 1 week
ask for resource reclamation again.
This is kind of dirty hack, but as last resort this is better then stuck
indefinitely because of KVA fragmentation, waiting until some random event
free something sufficient. OpenSolaris also has this hack in its vmem(9).
MFC after: 2 weeks
uintptr_t may be 64-bit on some platforms, therefore when
finding xrefinfo by pointer to device the high word is being
cut off due to cast to phandle_t which is 32-bit long by definition.
Due to that we loose the high word of the address to compare with
xi->dev's address.
To fix that, first argument of xrefinfo_find() is extended to
uintptr_t and is being cast to appropriate type (phandle_t)
when compared.
Submitted by: Zbigniew Bodek <zbb@semihalf.com>
Reviewed by: nwhitehorn
Obtained from: Semihalf
Handle the VIRQ_DEBUG signal and print a stack trace of each vCPU on the Xen
console. This is only used for debug purposes and is triggered by the
administrator of the Xen host.
Sponsored by: Citrix Systems R&D
MFC after: 1 week
This adds an upper bound, dtrace_ustackdepth_max, to the number of frames
traversed when computing the userland stack depth. Some programs - notably
firefox - are otherwise able to trigger an infinite loop in
dtrace_getustack_common(), causing a panic.
MFC after: 1 week
This is used by the 'athsurvey' command to print out channel survey
statistics - % busy times transmit, receive and airtime.
It's as buggy and incomplete as the rest of the HAL survey support -
notably, tying into the ANI code to read channel stats and occasionally
getting garbage counters isn't very nice. It also doesn't (yet!) get
channel survey information during a scan. But it's good enough for
basic air-time debugging, which is why I'm committing it in this state.
Tested:
* AR9380, STA mode
rathe than private in each HAL module.
Whilst here, modify ath_hal_private to always have the per-channel
noisefloor stats, rather than conditionally. This just makes
life easier in general (no strange ABI differences between different
HAL compile options.)
Add a couple of methods (clear/reset, add) rather than using
hand-rolled versions of things.
This symptom is "calibrations don't ever run", which may cause some
pretty spectacularly bad behaviour in noisy environments or with longer
uptimes.
Thanks to dtrace to make it easy to check if specific non-inlined functions
are getting called by things like the ANI and calibration HAL methods.
Grr.
Tested:
* AR9380, STA mode
Author: Ville Syrjälä <ville.syrjala@linux.intel.com>
Date: Fri May 31 12:17:08 2013 +0000
drm: Sort connector modes based on vrefresh
Keeping the modes sorted by vrefresh before the pixel clock makes the
mode list somehow more pleasing to the eye.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
PR: 198936
Obtained from: Linux
MFC after: 1 month
MFC with: r280183
