- Call lock_init() first before setting any lock_object fields in
lock init routines. This way if the machine panics due to a duplicate
init the lock's original state is preserved.
- Somewhat similarly, don't decrement td_locks and td_slocks until after
an unlock operation has completed successfully.
provided by Isilon.
- Add an rm_assert() supporting various lock assertions similar to other
locking primitives. Because rmlocks track readers the assertions are
always fully accurate unlike rw_assert() and sx_assert().
- Flesh out the lock class methods for rmlocks to support sleeping via
condvars and rm_sleep() (but only while holding write locks), rmlock
details in 'show lock' in DDB, and the lc_owner method used by
dtrace.
- Add an internal destroyed cookie so that API functions can assert
that an rmlock is not destroyed.
- Make use of rm_assert() to add various assertions to the API (e.g.
to assert locks are held when an unlock routine is called).
- Give RM_SLEEPABLE locks their own lock class and always use the
rmlock's own lock_object with WITNESS.
- Use THREAD_NO_SLEEPING() / THREAD_SLEEPING_OK() to disallow sleeping
while holding a read lock on an rmlock.
Submitted by: andre
Obtained from: EMC/Isilon
mbuf that was fully consumed by the previous call, the mbuf ptr returned by the
current call ends up being the previous mbuf in the sb chain to the one that
contains the data we want.
This does not cause any observable issues because the mbuf copy routines happily
walk the mbuf chain to get to the data at the moff offset, which in this case
means they effectively skip over the mbuf returned by sbsndptr().
We can't adjust sb->sb_sndptr during the previous call for this case because the
next mbuf in the chain may not exist yet. We therefore need to detect the
condition and make the adjustment during the current call.
Fix by detecting the special case of moff being at the start of the next mbuf in
the chain and adjust the required accounting variables accordingly.
Reviewed by: andre
MFC after: 2 weeks
star for me. EVENTHANDLER_DEREGISTER() attempts to acquire the lock which is
held by the event handler framework while executing event handler functions,
leading to deadlock.
Move EVENTHANDLER_DEREGISTER() to alq_load_handler() and thus deregister the ALQ
shutdown_pre_sync handler at module unload time, which takes care of the
originally reported panic and fixes the deadlock introduced in r250951.
Reported by: Luiz Otavio O Souza
MFC after: 3 days
X-MFC with: 250951
In order to get some coverage of C11 atomics in kernelspace, switch at
least one piece of code in kernelspace to use C11 atomics instead of
<machine/atomic.h>.
While there, slightly improve the code by adding an assertion to prevent
the use count from going negative.
ensure all per-vnet related hhook initialisation is completed prior to any
virtualised hhook points attempting registration.
vnet_register_sysinit() requires that a stage later than SI_SUB_VNET be chosen.
There are no per-vnet initialisors in the source tree at this time which run
earlier than SI_SUB_INIT_IF. A quick audit of non-virtualised SYSINITs indicates
there are no subsystems pre SI_SUB_MBUF that would likely be interested in
registering a virtualised hhook point.
Settle on SI_SUB_MBUF as hhook's per-vnet initialisation stage as it's the first
overtly network-related initilisation stage to run after SI_SUB_VNET. If a
subsystem that initialises earlier than SI_SUB_MBUF ends up wanting to register
virtualised hhook points in future, hhook's use of SI_SUB_MBUF will need to be
revisited and would probably warrant creating a dedicated SI_SUB_HHOOK which
runs immediately after SI_SUB_VNET.
MFC after: 1 week
hook functions into hhook points which register after the modules were loaded -
potentially useful during boot or if hhook points are dynamically registered.
MFC after: 1 week
hhook_{add|remove}_hook_lookup() so that khelp (and other potential API
consumers) do not have to care when they attempt to (un)hook a particular hook
point identified by id and type.
Reviewed by: scottl
MFC after: 1 week
KASSERT during TCP hhook registration at boot. Virtualised hook points only
require extra housekeeping and sanity checking when "options VIMAGE" is present.
Reported by: bdrewery,jh,dhw
Tested by: dhw
MFC after: 1 week
X-MFC with: 251732
type and id, as compared to virtualised hook points which are now uniquely
identified by type, id and a vid (which for vimage is the pointer to the vnet
that the hhook resides in).
All hhook_head structs for both virtualised and non-virtualised hook points
coexist in hhook_head_list, and a separate list is maintained for hhook points
within each vnet to simplify some vimage-related housekeeping.
Reviewed by: scottl
MFC after: 1 week
- When looping, check for the pending suspension. Otherwise, other
usermode thread which races with the looping one, could try to
prevent the process from stopping or exiting.
- Add missed checks for the faults from casuword*(). The code is
structured in a way which makes the loops exit if the specified
address is invalid, since both fuword() and casuword() return -1 on
the fault. But if the address is mapped readonly, the typical value
read by fuword() is different from -1, while casuword() returns -1.
Absent the checks for casuword() faults, this is interpreted as the
race with other thread and causes non-interruptible spinning in the
kernel.
Reported and tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
about mount and unmount events. This is used by Juniper to implement a more
optimal implementation of NetBSD's veriexec.
Submitted by: stevek@juniper.net
Obtained from: Juniper Networks, Inc
the mask of a cpuset. Also, change the cpuset's mask before updating the
masks of all children. Previously changing a cpuset's mask first required
setting the mask to a super-set of both the old and new masks and then
changing it a second time to the new mask.
- Split the bqlock into bqclean and bqdirty locks.
- Only acquire the wakeup synchronization locks when we cross a
threshold requiring them.
- Restructure the way flushbufqueues() targets work so they are more
smp friendly and sane.
Reviewed by: kib
Discussed with: mckusick, attilio
Sponsored by: EMC / Isilon Storage Division
M vfs_bio.c
of a lock within a single thread.
- Fix handling of interlocks in WITNESS by properly requiring the interlock
to be held exactly once if it is specified.
the vnode lock while iterating over the free vnode list. Instead of
yielding, pause for 1 tick. The change is reported to help in some
virtualized environments.
Submitted by: Roger Pau Monn? <roger.pau@citrix.com>
Discussed with: jilles
Tested by: pho
MFC after: 2 weeks
space, fork(2) would cause shadowing of the physical object and
copying of the shared page into private copy, effectively preventing
updates for the exported timehands structure and stopping the clock.
Specify the maximum allowed permissions for the page to be read and
execute, preventing write from the user mode.
Reported and tested by: <huanghwh@yahoo.com>
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
used as the estimation of size, to 32GB. This provides around 100K of
buffer headers and corresponding KVA for buffer map at the peak.
Sizing the cache larger is not useful, also resulting in the wasting
and exhausting of KVA for large machines.
Reported and tested by: bdrewery
Sponsored by: The FreeBSD Foundation
requires a pkthdr being present but that's not the case for either
_bus_dmamap_load_mbuf_sg() or bus_dmamap_load_mbuf_sg(9).
Reported by: sbruno
MFC after: 1 week
- Use a shared bufobj lock in getblk() and inmem().
- Convert softdep's lk to rwlock to match the bufobj lock.
- Move INFREECNT to b_flags and protect it with the buf lock.
- Remove unnecessary locking around bremfree() and BKGRDINPROG.
Sponsored by: EMC / Isilon Storage Division
Discussed with: mckusick, kib, mdf
be a GOOD IDEA (TM).
Apparently MOST users set this (e.g. tcp and friends) but there are a few
users that just assume that it is a sensible value but then go on to read it.
These include SCTP, pf and the FLOWTABLE option (and maybe others).
avoid a dangling pointer and eventual panic on system shutdown.
Reported by: Ali <comnetboy at gmail.com>
Tested by: Ali <comnetboy at gmail.com>
MFC after: 1 week
from 1k to 20k The previous value was good 10 years ago, but not
anymore now.
More importantly, lots of good surprises:
polling is incredibly effective under virtualization, and not only
prevents livelock but also saves most of the VM exit overhead in
receive mode.
Using polling, a FreeBSD instance under qemu-kvm remains perfectly
responsive even when bombed with 10 Mpps over an emulated e1000,
and happily processes 1.7 Mpps through ipfw.
Note that some incompatibilities still remain: e.g. polling is not
(yet) compatible with netmap, and seems to freeze the guest when
kern.polling.idle_poll=1
MFC after: 3 days
the right type for the argument in syscalls.master. Also fix the
posix_fallocate(2) and posix_fadvise(2) compat32 syscalls on the
architectures which require padding of the 64bit argument.
Noted and reviewed by: jhb
Pointy hat to: kib
MFC after: 1 week
apply to most jails but do apply to vnet jails. This includes adding
a new sysctl "security.jail.vnet" to identify vnet jails.
PR: conf/149050
Submitted by: mdodd
MFC after: 3 days
with any structure containing a uint64_t index. The tree code
auto-generates type safe wrappers.
- Eliminate the buf splay and replace it with pctrie. This is not only
significantly faster with large files but also allows for the possibility
of shared locking.
Reviewed by: alc, attilio
Sponsored by: EMC / Isilon Storage Division
null_hashget() obtains the reference on the nullfs vnode, which must
be dropped.
- Fix a wart which existed from the introduction of the nullfs
caching, do not unlock lower vnode in the nullfs_reclaim_lowervp().
It should be innocent, but now it is also formally safe. Inform the
nullfs_reclaim() about this using the NULLV_NOUNLOCK flag set on
nullfs inode.
- Add a callback to the upper filesystems for the lower vnode
unlinking. When inactivating a nullfs vnode, check if the lower
vnode was unlinked, indicated by nullfs flag NULLV_DROP or VV_NOSYNC
on the lower vnode, and reclaim upper vnode if so. This allows
nullfs to purge cached vnodes for the unlinked lower vnode, avoiding
excessive caching.
Reported by: G??ran L??wkrantz <goran.lowkrantz@ismobile.com>
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
locks. To support this, VNODE locks are created with the LK_IS_VNODE
flag. This flag is propagated down using the LO_IS_VNODE flag.
Note that WITNESS still records the LOR. Only the printing and the
optional entering into the kernel debugger is bypassed with the
WITNESS_NO_VNODE option.
all requested data was sent. The reason is that xfsize <= 0 condition
must not be tested at all if space == loopbytes. Otherwise, the done
is set to 1, and sendfile(2) is aborted too early.
Instead of moving the condition to exiting the inner loop after the
xfersize check, directly check for the completed transfer before the
testing of the available space in the socket buffer, and revert item 1
of r248830. It is arguably another bug to sleep waiting for socket
buffer space (or return EAGAIN for non-blocking socket) if all bytes
are already transferred.
Reported by: pho
Discussed with: scottl, gibbs
Tested by: scottl (stable/9 backport), pho
