Specifically, sleepq_broadcast() uses td_slpq for its private pending
queue of threads that it is going to wake up after it takes them off the
sleep queue. The problem is that if one of the threads is actually not
asleep yet, then we can end up with td_slpq being corrupted and/or the
thread being made runnable at the wrong time resulting in the td_sleepqueue
== NULL assertion failures occasionally reported under heavy load.
The fix is to stop being so fancy and ditch the whole pending queue bit.
Instead, sleepq_remove_thread() and sleepq_resume_thread() were merged
into one function that requires the caller to hold sched_lock. This
fixes several places that unlocked sched_lock only to call a function
that then locked sched_lock, so even though sched_lock is now held
slightly longer, removing the extra lock acquires (1 pair instead of 3
in some cases) probably makes it an overall win if you don't include the
fact that it closes a race. This is definitely a 5.4 candidate.
PR: kern/79693
Submitted by: Steven Sears stevenjsears at yahoo dot com
MFC after: 4 days
was satisified for the rest of the kernel on the i386 build except for
these two files. Rather than adding a submarine include to pcb.h, I've
added proc.h here.
I forgot to include these with the original commit. Sorry folks.
period value. I suppose the BT adapter driver should be
fixed, but more importantly we should protect against
dividing by zero.
PR: kern/75603
MFC after: 1 week
of the kernel address space already. Intel recommend this anyway, because
using a non-4GB limit adds an additional clock cycle to address generation.
We were able to install 4GB segments into the LDT, so any limits we imposed
on %cs and %ds were academic anyway. More importantly, this allows us to
make a page in the kernel readable to user applications, for holding things
like the signal trampoline and other fun things.
Move the user %cs/%ds segments from the LDT to the GDT. There was no good
reason for them to be there anyway. The old LDT entries are still there
but we can now relax the restriction that prevented users from emptying
the default LDT entries.
Putting user and kernel %cs and %ds together allows us to access the fast
sysenter/sysexit/syscall/sysret instructions. syscall/sysret in particular
require that the user/kernel segments be laid out this way. Reserve a slot
specifically for NDIS while here.
Create two user controllable slots in the GDT that are context switched
with the (kernel) thread. This allows user applications to set two
user privilige selectors to arbitary values. Create
i386_set_fsbase(void *base) and friends. (get/set, fs/gs). For i386,
%gs is used by tls and the thread libraries and this means that user
processes no longer have to have the cost of having a custom LDT, and
we will no longer to do a ldt switch when activating a kthread/ithread in
the usual case any more.
In other words, we can now set the base address for %fs and %gs to arbitary
addresses without the pain of messing with ldt segments.
of the __pcb_spare longs. Except that fields were changed and one of the
spare values was used and the __pcb_spare field was reduced from two to one
long. Now VM86 bios calls can trash the first 4 bytes of the next page
following the kernel stack/pcb. This Is Bad(TM). This bug has been
present in 5.2-release and onwards, and is still in RELENG_5.
Instead of tempting fate and trying to use "spare" fields, explicitly
reserve them.
pcib_route_interrupt interface. Since there's only one interrupt pin
in the CardBus form factor, everybody gets to share it. Implement
cbb_route_interrupt to return the interrupt we have.
Suggested by: bms
Otherwise, busses that implement the pcib interface that forget to
implement pcib_route_interrupt would return EIO, which the caller
interprets as 'use interrupt 6'. This is likely the cause of much of
the grief that we had when I enabled power modes for the cardbus
bridge, since the card needed to reroute the interrupt to it and it
was getting 6 which was d by the pccbb sanity checks.
Also, move the -I stuff to the centralized kern.pre.mk. However, it
might be better to add these flags to files.conf. This is a short
term fix to fix the broken builds on my machine (I don't have a valid
/sys link).
guard against NULL t_modem entry. Otherwise, driver doesn't have t_modem
callback implemented(such like sys/dev/usb/ucycom.c) would panic when
someone opens the driver's associated tty device.
Reviewed by: phk, sam (mentor)
case. There are bugs in some which didn't unlock in the ISDOTDOT case
to begin with that need to be addressed seperately. This simplifies
things anyway.
- Fix relookup() to prevent it from vrele()'ing the dvp while the vp
is locked. Catch up to other lookup changes.
Sponsored by: Isilon Systems, Inc.
Reported by: Peter Wemm
Enhanced SpeedStep (that is, a follow-up of it called Foxton). Until
we actually have support for that, we build to catch regressions in
the framework.
Triggered by: njl
