- threadA runs vfs_rel(mp1)
- threadB does unmount the mp1 fs, sets MNTK_UNMOUNT and drop MNT_ILOCK()
- threadA runs vfs_busy(mp1) and, as long as, MNTK_UNMOUNT is set, sleeps
waiting for threadB to complete the unmount
- threadB, in vfs_mount_destroy(), finds mnt_lock > 0 and sleeps waiting
for the refcount to expire.
Fix the deadlock by adding a flag called MNTK_REFEXPIRE which signals the
unmounter is waiting for mnt_ref to expire.
The vfs_busy contenders got awake, fails, and if they retry the
MNTK_REFEXPIRE won't allow them to sleep again.
2) Simplify significantly the code of vfs_mount_destroy() trimming
unnecessary codes:
- as long as any reference exited, it is no-more possible to have
write-op (primarty and secondary) in progress.
- it is no needed to drop and reacquire the mount lock.
- filling the structures with dummy values is unuseful as long as
it is going to be freed.
Tested by: pho, Andrea Barberio <insomniac at slackware dot it>
Discussed with: kib
anything other than 0. Make it so. This fixes
"panic: VOP_STRATEGY failed bp=0xc320dd90 vp=0xc3b9f648",
encountered when writing to an orphaned filesystem. Reason
for the panic was the following assert:
KASSERT(i == 0, ("VOP_STRATEGY failed bp=%p vp=%p", bp, bp->b_vp));
at vfs_bio:bufstrategy().
Reviewed by: scottl, phk
Approved by: rwatson (mentor)
Sponsored by: FreeBSD Foundation
result in panic:
mdconfig -af blah.img -o force
mount /dev/md0 /mnt
mdconfig -du 0
Reviewed by: scottl
Approved by: rwatson (mentor)
Sponsored by: FreeBSD Foundation
o Add support for compiling elf64 for this file (the rest of the changes are
coming later)
o Fill in some misssing relocation types. We need to support these in
elf_machdep.c's relocation routines eventually, but that's future work
too.
the device, which means refcount on periph drivers never drops,
which means cam_sim_free() never returns, which results in umass
sleeping there ad infinitum.
Submitted by: pjd
Reviewed by: scottl, pjd
Approved by: rwatson (mentor)
Sponsored by: FreeBSD Foundation
unregistration, and execution:
- Add some brackets for clarity and trim a bit of vertical whitespace.
- Remove comments that may not contribute to clarity, such as "Lock"
before acquiring a lock and "Get memory" before allocating memory.
- During hook registration, don't drop pfil_list_lock between checking
for a duplicate and registering the hook, as this leaves a race
condition by failing to enforce the "no duplicate hooks" invariant.
- Don't lock the hook during registration, since it's not yet in use.
- Document assumption that hooks will be quiesced before being
unregistered.
- Don't write-lock hooks during removal because they are assumed
quiesced.
- Rename "done" label to "locked_error" to be clear that it's an error
path on the way out of hook execution.
MFC after: pretty soon
does - in DragonFly, it's cam_sim_release() what actually frees the
SIM; cam_sim_free does nothing more than calling cam_sim_release().
Here, we drain in cam_sim_free, waiting for refcount to drop to zero.
We cannot do the same think DragonFly does, because after cam_sim_free
returns, client would destroy the sim->mtx, and CAM would trip over
an initialized mutex.
Reviewed by: scottl
Approved by: rwatson (mentor)
Sponsored by: FreeBSD Foundation
to actually use it would panic on mtx operation, as dead_sim doesn't
have a proper mutex. Even if it had a properly initialized mutex,
it wouldn't have properly locked and owned one.
Reviewed by: scottl
Approved by: rwatson (mentor)
Sponsored by: FreeBSD Foundation
configuration registers (which are not going to change) on every interrupt
looks expensive, especially when interrupt is shared. Profiling shows me 3%
of time spent by atapci0 on pure network load due to IRQ sharing with em0.
separate index variable.
It gives more then double rc4_init() performance increase on tested i386 P4.
It also gives about 15% speedup to PPTP VPN with stateless MPPE encryption
(by ng_mppc) which calls rc4_init() for every packet.
- Initialize variables before use.
- Remove a KASSERT() that could falsely trigger if there are other sources
of NMIs in the system.
Efficiency tweak:
- When checking PMCs that overflowed, ignore PMCs that were not configured for
sampling.
a real packet error but simply indicate that an unexpected unicast or multicast
error was received by the NIC, which was not counted in the past as well.
Reported by: many (on -stable@)
Reviewed by: davidch
MFC after: 3 days
On HyperThreading CPUs logical cores have same frequency, so setting it
on any core will change the other's one. In most cases first request
to the second core will be the "set" request, done after setting frequency
of the first core. In such case second CPU will obtain throttled frequency
of the first core as it's max_mhz making cpufreq broken due to different
frequency sets.
(e.g. ath): we must check the key index and not whether the key
points at a cipher other than "undef". This looks like it's been
broken for a while. Might be worth adding an explicit clear cipher
at some point though this would require changes to the usage of
IEEE80211_KEY_UNDEFINED.
PR: 125906
