This mirrors code in tmpfs.
This changge shouldn't affect much read path, it may cause unnecessary
vm_page_lookup calls in the case where v_object has no active or inactive
pages but has some cache pages. I believe this situation to be non-essential.
In write path this change should allow us to properly detect the above
case and free a cache page when we write to a range that corresponds to it.
If this situation is undetected then we could have a discrepancy between
data in page cache and in ARC or on disk.
This change allows us to re-enable vn_has_cached_data() check in zfs_write.
NOTE: strictly speaking resident_page_count and cache fields of v_object
should be exmined under VM_OBJECT_LOCK, but for this particular usage
we may get away with it.
Discussed with: alc, kib
Approved by: pjd
Tested with: tools/regression/fsx
MFC after: 3 weeks
artificial power-of-2 rounded number to their real values specified
in RFC879 and RFC2460.
From the history and existing comments it appears that the rounded
numbers were intended to be advantageous for the kernel and mbuf
system. However this hasn't been the case at for at least a long
time. The mbuf clusters used in tcp_output() have enough space
to hold the larger real value for the default MSS for both IPv4 and
IPv6. Note that the default MSS is only used when path MTU discovery
is disabled.
Update and expand related comments.
Reviewed by: lsteward (including some word-smithing)
MFC after: 2 weeks
Otherwise, adding insult to injury, in addition to double-caching of data
we would always copy the data into a vnode's vm object page from backend.
This is specific to sendfile case only (VOP_READ with UIO_NOCOPY).
PR: kern/141305
Reported by: Wiktor Niesiobedzki <bsd@vink.pl>
Reviewed by: alc
Tested by: tools/regression/sockets/sendfile
MFC after: 2 weeks
The workaround was incorrectly documented as having something to do with
set_pcpu section's progbits, but in fact it was for incorrect placement
of __start_set_pcpu because of the bug in ld.
The bug was fixed in r210245, see commit message for details.
A side-effect of the workaround was that a zero-size set_pcpu section was
produced for modules, source code of which included pcpu.h but didn't
actually define any dynamic per-cpu variables.
This commit should remove the side-effect.
The same workaround is present sys/net/vnet.h, has an analogous side-effect
and can be removed as well.
An UPDATING entry that warns about a need for recent ld is following.
MFC after: 1 month
include/mmuvar.h - Change the MMU_DEF macro to also create the class
definition as well as define the DATA_SET. Add a macro, MMU_DEF_INHERIT,
which has an extra parameter specifying the MMU class to inherit methods
from. Update the comments at the start of the header file to describe the
new macros.
booke/pmap.c
aim/mmu_oea.c
aim/mmu_oea64.c - Collapse mmu_def_t declaration into updated MMU_DEF macro
The MMU_DEF_INHERIT macro will be used in the PS3 MMU implementation to
allow it to inherit the stock powerpc64 MMU methods.
Reviewed by: nwhitehorn
of small maxsize and "large" (including BUS_SPACE_UNRESTRICTED) nsegments
parameters. Generally using a presz of 0 (which indeed might indicate the
use of bogus parameters for DMA tag creation) is not fatal, it just means
that no additional DVMA space will be preallocated.
to handle current timecounter wraps. Make kern_clocksource.c to honor that
requirement, scheduling sleeps on first CPU for no more then specified
period. Allow other CPUs to sleep up to 1/4 second (for any case).
Do not explicitly enable interrupts in smp_init_secondary() because it
renders any spinlock protected code after that point to run with
interrupts enabled. This is because the processor is executing in the
context of idlethread whose 'md_spinlock_count' is already set to 1.
Instead just let sched_throw() re-enable interrupts when it releases
the spinlock.
The original powerpc commit log for r212559 is available here:
http://svn.freebsd.org/viewvc/base?view=revision&revision=212559
when the original offset is bigger than size of one page. X86BIOS macros
cannot be used here because it is assumed address is only linear in a page.
Tested by: netchild
unexpected things in copyout(9) and so wiring the user buffer is not
sufficient to perform a copyout(9) while holding a random mutex.
Requested by: nwhitehorn
Sponsored by: The FreeBSD Foundation
> Description of fields to fill in above: 76 columns --|
> PR: If a GNATS PR is affected by the change.
> Submitted by: If someone else sent in the change.
> Reviewed by: If someone else reviewed your modification.
> Approved by: If you needed approval for this commit.
> Obtained from: If the change is from a third party.
> MFC after: N [day[s]|week[s]|month[s]]. Request a reminder email.
> Security: Vulnerability reference (one per line) or description.
> Empty fields above will be automatically removed.
M param.h
any spin locks acquired between the enabling of interrupts in
machdep_ap_bootstrap() and the invocation of the scheduler would fail to
have interrupts disabled due to the fake spinlock already held by the
idle thread. sched_throw(NULL) will enable interrupts by itself when
exiting this spinlock, so just let it do that and don't enable interrupts
here.
understand everything correctly, we don't really need it.
- Provide default numeric value as strings. This allows to simplify
a lot of code.
- Bump version number.
- Remove sync from msgrng_send, sync needs to be called just once before
sending.
- Fix retry logic - don't reload registers when retrying in message_send,
also fix check for send pending fail.
- remove unused message_send_block_fast()
- merge message_receive_fast() to message_receive
- style(9) fixes, and comments
- rge and nlge updated for the sys/mips/rmi/msgring.h changes
ACPI specification sates that if P_LVL2_LAT > 100, then a system doesn't
support C2; if P_LVL3_LAT > 1000, then C3 is not supported.
But there are no such rules for Cx state data returned by _CST. If a
state is not supported it should not be included into the return
package. In other words, any latency value returned by _CST is valid,
it's up to the OS and/or user to decide whether to use it.
Submitted by: nork
Suggested by: mav
MFC after: 1 week
If a kobj method doesn't have any explicitly provided default
implementation, then it is auto-assigned kobj_error_method.
kobj_error_method is proper only for methods that return error code,
because it just returns ENXIO.
So, in the case of unimplemented bus_add_child caller would get
(device_t)ENXIO as a return value, which would cause the mistake to go
unnoticed, because return value is typically checked for NULL.
Thus, a specialized null_add_child is added. It would have sufficied
for correctness to return NULL, but this type of mistake was deemed to
be rare and serious enough to call panic instead.
Watch out for this kind of problem with other kobj methods.
Suggested by: jhb, imp
MFC after: 2 weeks
The main goal of this is to generate timer interrupts only when there is
some work to do. When CPU is busy interrupts are generating at full rate
of hz + stathz to fullfill scheduler and timekeeping requirements. But
when CPU is idle, only minimum set of interrupts (down to 8 interrupts per
second per CPU now), needed to handle scheduled callouts is executed.
This allows significantly increase idle CPU sleep time, increasing effect
of static power-saving technologies. Also it should reduce host CPU load
on virtualized systems, when guest system is idle.
There is set of tunables, also available as writable sysctls, allowing to
control wanted event timer subsystem behavior:
kern.eventtimer.timer - allows to choose event timer hardware to use.
On x86 there is up to 4 different kinds of timers. Depending on whether
chosen timer is per-CPU, behavior of other options slightly differs.
kern.eventtimer.periodic - allows to choose periodic and one-shot
operation mode. In periodic mode, current timer hardware taken as the only
source of time for time events. This mode is quite alike to previous kernel
behavior. One-shot mode instead uses currently selected time counter
hardware to schedule all needed events one by one and program timer to
generate interrupt exactly in specified time. Default value depends of
chosen timer capabilities, but one-shot mode is preferred, until other is
forced by user or hardware.
kern.eventtimer.singlemul - in periodic mode specifies how much times
higher timer frequency should be, to not strictly alias hardclock() and
statclock() events. Default values are 2 and 4, but could be reduced to 1
if extra interrupts are unwanted.
kern.eventtimer.idletick - makes each CPU to receive every timer interrupt
independently of whether they busy or not. By default this options is
disabled. If chosen timer is per-CPU and runs in periodic mode, this option
has no effect - all interrupts are generating.
As soon as this patch modifies cpu_idle() on some platforms, I have also
refactored one on x86. Now it makes use of MONITOR/MWAIT instrunctions
(if supported) under high sleep/wakeup rate, as fast alternative to other
methods. It allows SMP scheduler to wake up sleeping CPUs much faster
without using IPI, significantly increasing performance on some highly
task-switching loads.
Tested by: many (on i386, amd64, sparc64 and powerc)
H/W donated by: Gheorghe Ardelean
Sponsored by: iXsystems, Inc.
