state structure. This field is only for CCBs that are associated with
actions that are occurring on the HBA (i.e., XPT_CONT_IO actions).
This way we also don't get confused when the upstream listener stalls
try and look at a CCB which has already been freed (by CAM).
to reduce the pv_entry_count counter. This was found by Tor Egge. In the
same email, Tor also pointed out the pv_stats problem in the previous
commit, but I'd forgotten about it until I went looking for this email
about this allocation problem.
locked. In general the adaptive spinning is similar to the same code
for mutexes with some extra trickiness in rw_wunlock_hard(). Specifically,
even though both wait bits might be set and we might have a turnstile with
at least one waiting thread, there might not be any threads blocked on the
queue we are not waking up (they might all be spinning), and we should
only preserve the waiting flag for the queue we aren't waking up if there
are in fact threads blocked on that queue. Secondly, there might not be
any threads blocked on the queue we have chosen to waken threads from
(there might only be threads blocked on the other queue and the threads
for this queue are all spinning) in which case we disown the turnstile
instead of doing a braodcast and unpend.
stored in metadata instead of an offset in single disk.
After reboot/crash synchronization process started from a wrong offset
skipping (not synchronizing) part of the component which can lead to data
corrutpion (when synchronization process was interrupted on initial
synchronization) or other strange situations like 'graid3 status' showing
value more than 100%.
Reported, reviewed and tested by: ru
Reported by: Dmitry Morozovsky <marck@rinet.ru>
MFC after: 1 day
as pcf_ebus and pcf_isa, they should probably be fixed back to pcf),
and bti2c doesn't exist, bktr has smbus or iicbb as children..
Brought to you by: http://people.FreeBSD.org/~jmg/driver.pdf
use it in places that only care about the write owner instead of
rw_owner() as a baby step towards limited read-lock owner.
- Tidy the code that sets the WAITER flag bits to not duplicate a test
around the atomic operation and the KTR trace in both of the lock
functions.
above what's used for fast interrupts, only interrupts with the level of
the interrupt which led to calling intr_fast() (which is used with both
fast and ithread interrupts) are blocked while in that function. Thus
intr_fast() can be preempted by a fast interrupt (which are of a higher
level than ithread interrupts) while servicing an ithread interrupt. This
can lead to a stale pointer to the head of the active interrupt requests
list when back in the ithread interrupt invocation of intr_fast(), in turn
resulting in corruption of the interrupt request lists and consequently
in a panic. Solve this be turning off interrupts in intr_fast() before
reading the pointer to the head of the active list rather than after. [1]
- Add a KASSERT in intr_fast() which asserts that ir_func is non-zero before
calling it. [1]
- Increment interrupt stats after calling the handlers rather than before.
This reduces the delay until direct and fast handlers are serviced, in my
testings by 30% on average for the direct tick interrupt handler, in turn
resulting in less clock drift.
PR: 94778 [1]
Submitted by: Andrew Belashov [1]
MFC after: 2 weeks
with a given module_t. I use this in some the MOD_LOAD event handler for
some test kernel modules to ask the kernel linker to look up the linker
sets in my test modules. (I use linker sets to generate the list of
possible events that I then signal to execute via a sysctl. On non-amd64,
ld(8) would resolve the entire linker set, but on amd64 I have to ask the
kernel linker to do it for me, and having the kernel linker do it works on
all archs.)
if the specified priority is zero. This avoids a race where the calling
thread could read a snapshot of it's current priority, then a different
thread could change the first thread's priority, then the original thread
would call sched_prio() inside msleep() undoing the change made by the
second thread. I used a priority of zero as no thread that calls msleep()
or tsleep() should be specifying a priority of zero anyway.
The various places that passed 'curthread->td_priority' or some variant
as the priority now pass 0.
have not been passed to the h/w yet. This remedies watchdog timeout
of buffered multicast frames in hostap mode.
While here eliminate an extraneous check; ieee80211_beacon_update sets
the tim bit based on ncabq != 0 so there's no reason to check it too.
Noticed by: Christophe Prevotaux
compiler doesn't decide to cache td_state. Cachine the state would cause
the spinning thread to not notice when the owning thread stopped executing
(if it was preempted for example) which could result in livelock.
than keeping it locked until we exit the function to optimize the case
where the lock would be dropped and later reacquired. The optimization
was broken when kevent's were moved from UFS to VFS and the knote list
lock for a vnode kevent became the lockmgr vnode lock. If one tried
to use a kqueue that contained events for a kqueue fd followed by a vnode,
then the kq global lock would end up being held when the vnode lock was
acquired which could result in sleeping with a mutex held (and subsequent
panics) if the vnode lock was contested.
Reviewed by: jmg
Tested by: ps (on 6.x)
MFC after: 3 days
not need to clear it now, this should fix panic when msleep is recursivly
called. Patch is slightly adjusted after review.
Reviewed by: jhb
Tested by: Csaba Henk, csaba-ml at creo.hu
MFC after: 3 days
Strong candidate for backport to 6.x.
When allocating new blocks, the search for block group beginnings
would fail with a segfault. There was a side-effect read access with
an off-by-one errors. The results were not used in the error case so
the code worked in the past. But now the FreeBSD kernel has tighter
mappings and the word accessed is not mapped (for me).
The Linux kernel has rewritten most of the allocation strategy by now.
Also, the Linux kernel cleaned up the integration of these files and
it look feasable to wrap the original Linux files in wrapper that
provides their favorite arguments instead of dragging around our own
code.
