the wrong direction. Before it, if preemption and end of time slice happen
same time, thread was put to the head of the queue as for only preemption.
It could cause single thread to run for indefinitely long time. r220198
handles it by not clearing TDF_NEEDRESCHED in case of preemption. But that
causes delayed context switch every time preemption happens, even when not
needed.
Solve problem by introducing scheduler-specifoc thread flag TDF_SLICEEND,
set when thread's time slice is over and it should be put to the tail of
queue. Using SW_PREEMPT flag for that purpose as it was before just not
enough informative to work correctly.
On my tests this by 2-3 times reduces run time deviation (improves fairness)
in cases when several threads share one CPU.
Reviewed by: fabient
MFC after: 2 months
Sponsored by: iXsystems, Inc.
With switchticks variable being reset each time thread preempted (that is
done regularly by interrupt threads) scheduling quantum may never expire.
It was not noticed in time because several other factors still regularly
trigger context switches.
Handle the problem by replacing that mechanism with its equivalent from
SCHED_ULE called time slice. It is effectively the same, just measured in
context of stathz instead of hz. Some unification is probably not bad.
Reduce the size of a PV entry by eliminating pv_ptem. There is no need
to store a pointer to the page table page in the PV entry because it is
easily computed during the walk down the page table.
Eliminate the ptphint from the pmap. Long, long ago, page table pages
belonged to a vm object, and we would look up page table pages based
upon their offset within this vm object. In those days, this hint may
have had tangible benefits.
Tested by: jchandra
Apart from the fact that nothing should have OPEN_MAX as a limit (as opposed
to RLIMIT_NOFILE from getrlimit() or _SC_OPEN_MAX from sysconf()), POSIX
does not require us to check this. POSIX does have a requirement on the
application that maxfds not exceed {OPEN_MAX}, but does not require the
implementation to check it ("may fail").
PR: 95239
Apart from the fact that nothing should have OPEN_MAX as a limit (as opposed
to RLIMIT_NOFILE from getrlimit() or _SC_OPEN_MAX from sysconf()), POSIX
does not require us to check this.
PR: 95239
Submitted by: Todd Miller
- Move destruction of per-ring locks to netmap_dtor_locked to mirror the
initialization that happens in NIOCREGIF. Otherwise unloading a netmap-
capable interface that was never put into netmap mode would try to
mtx_destroy an uninitialized mutex, and panic.
- Destroy core_lock in netmap_detach, mirroring init in netmap_attach.
- Also comment out the knlist_destroy for now as there is currently no
knlist_init.
Sponsored by: ADARA Networks
Reviewed by: luigi@
CCB at a time outstanding reliable. It's not there yet, but this
is the direction to go in so might as well commit. So far,
multiple at a time CCBs work (see ISP_INTERNAL_TARGET test mode),
but it fails if there are more downstream than the SIM wants
to handle and SRR is sort of confused when this happens, plus
it is not entirely quite clear what one does if a CCB/CTIO fails
and you have more in flight (that don't fail, say) and more queued
up at the SIM level that haven't been started yet.
Some of this is driven because there apparently is no flow control
to requeue XPT_CONTINUE_IO requests like there are for XPT_SCSI_IO
requests. It is also more driven in that the few target mode
periph drivers there are are not really set up for handling pushback-
heck most of them don't even check for errors (and what would they
really do with them anyway? It's the initiator's problem, really....).
The data transfer arithmetic has been worked over again to handle
multiple outstanding commands, so you have a notion of what's been
moved already as well as what's currently in flight. It turns that
this led to uncovering a REPORT_LUNS bug in the ISP_INTERNAL_TARGET
code which was sending back 24 bytes of rpl data instead of the
specified 16. What happened furthermore here is that sending back
16 bytes and reporting an overrun of 8 bytes made the initiator
(running FC-Tape aware f/w) mad enough to request, and keep
requesting, another FCP response (I guess it didn't like the answer
so kept asking for it again).
Sponsored by: Spectralogic
MFC after: 1 month
This is mostly a no-op other than for ARM where it adds missing
__aeabi_mem* and __aeabi_*divmod functions. Even on ARM these will remain
unused until the rest of the ARM EABI code is merged.
protect against 32-bit TSC overflow while the sync test is running.
On dual-socket Xeon E5-2600 (SNB) systems with up to 32 threads, there
is non-trivial chance (2-3%) that TSC synchronization test fails due to
32-bit TSC overflow while the synchronization test is running.
Sponsored by: Intel
Reviewed by: jkim
Discussed with: jkim, kib
This fixes "Negative sc_ref" panic possible when sysctl_kern_geom_confxml()
is run simultaneously with destroying GATE device.
Reviewed by: pjd
MFC after: 3 days
Starting or stopping the IPMI watchdog is rather expensive with the
current implementation as all IPMI requests are bounced via thread.
This is not viable during shutdown or dumps, and this avoids headache
in the common case that the watchdog is not enabled. The IPMI watchdog
should probably be reworked to not use a separate thread to fix this
in the case when the watchdog timer is enabled.
MFC after: 2 weeks
typical hypervisor does not implement access to the required MSR,
causing #GP on boot.
Reported and tested by: olgeni
PR: amd64/170388
MFC after: 3 days
ago, sleeping on busy pages in vm_pageout_launder() made sense. The call
to vm_pageout_flush() specified asynchronous I/O and sleeping on busy pages
blocked vm_pageout_launder() until the flush had completed. However, in
CVS revision 1.35 of vm/vm_contig.c, the call to vm_pageout_flush() was
changed to request synchronous I/O, but the sleep on busy pages was not
removed.
Make the process of embedding MDROOT images less perilous by
makeing the target that links kernel and embedding the image
depend on the image. This means, if the image doesn't exist you
find out before you try to boot from it and that if you change
the image you don't have to touch some random source file to
cause a rebuild.
Don't hide that we're embedding the image.
return. This silences a warning from clang 3.2 about uninitialized use
of the variable 'mediasize' in sbin/ggate/shared/ggate.c.
Reviewed by: pjd
MFC after: 1 week
packet delivery, always enqueue when possible. Also
correct the DEPLETED test as multiple bits might be
set. Thanks to Randall Stewart for the changes!
on the secondary side of a bridge will not be propagated to the primary
bus unless this is enabled. Busmastering is not enabled by default (we
have relied on firmware to set this bit to date). The OS needs to set it
for any bridges not configured by system firmware.
Tested by: Steve Polyack korvus comcast net
MFC after: 2 weeks
'fw_hdr_intfver' into an anonymous enum, which avoids a clang 3.2
warning about all the enum values being the same value.
Reviewed by: np
MFC after: 1 week
In rare event when fast and ithread interrupts share the same vector
and the fast handler was registered first, we can end up trying to
schedule the ithread that is not created yet. The kernel built with
INVARIANTS then triggers an assertion.
Change the order to create the ithread first and only then add the
handler that needs it to the interrupt event handlers list.
Reviewed by: jhb
(SYSBEGIN/SYSEND are specific to ipfw/dummynet and are used to
emulate sysctl on platforms that do not have them, and they work
by creating an array which contains all the sysctl-ed symbols.)
When issuing a non-DMA command, make sure to set the "remaining length of
command to be transferred via DMA" (sc_cmdlen) to zero up-front, otherwise
we might get confused on command competition interrupt (no DMA active but
still data left to transfer).
- Implement handling of MSG_IGN_WIDE_RESIDUE which some targets produce, as
just rejecting these leads to a resend and disconnect loop.
Reported and tested by: mjacob
MFC after: 3 days
