lock collision.
2. Fix two race conditions. One is between _umtx_unlock and signal,
also a thread was marked TDF_UMTXWAKEUP by _umtx_unlock, it is
possible a signal delivered to the thread will cause msleep
returns EINTR, and the thread breaks out of loop, this causes
umtx ownership is not transfered to the thread. Another is in
_umtx_unlock itself, when the function sets the umtx to
UMTX_UNOWNED state, a new thread can come in and lock the umtx,
also the function tries to set contested bit flag, but it will
fail. Although the function will wake a blocked thread, if that
thread breaks out of loop by signal, no contested bit will be set.
to do a window update to the peer (thru an ACK) from soreceive()
itself. TCP will do that upon return from the socket callback.
Sending a window update from soreceive() results in a lock reversal.
Submitted by: Mohan Srinivasan mohans at yahoo-inc dot com
Reviewed by: rwatson
soreceive(), then pass in M_DONTWAIT to m_copym(). Also fix up error
handling for the case where m_copym() returns failure.
Submitted by: Mohan Srinivasan mohans at yahoo-inc dot com
Reviewed by: rwatson
that the exclusive lock is already held, then we call panic. Don't
clobber internal lock state before panic'ing. This change improves
debugging if this case were to happen.
Submitted by: Mohan Srinivasan mohans at yahoo-inc dot com
Reviewed by: rwatson
instead acquire it conditionally in closef() if it is required for
advisory locking. This removes Giant from the close() path of sockets
and pipes (and any other objects that don't acquire Giant in their
fo_close path, such as kqueues). Giant will still be acquired twice for
vnodes -- once for advisory lock teardown, and a second time in the
fo_close method. Both Poul-Henning and I believe that the advisory lock
teardown code can be moved into the vn_closefile path shortly.
This trims a percent or two off the cost of most non-vnode close
operations on SMP, but has a fairly minimal impact on UP where the cost
of a single mutex operation is pretty low.
release the pipe mutex before calling fsetown(), as fsetown()
may block. The sigio code protects the pipe sigio data using
its own mutex, and the pipe reference count held by the caller
will prevent the pipe from being prematurely garbage-collected.
Discovered by: imp
setting the B_REMFREE flag in the buf. This is done to prevent lock order
reversals with code that must call bremfree() with a local lock held.
This also reduces overhead by removing two lock operations per buf for
fsync() and similar.
- Check for the B_REMFREE flag in brelse() and bqrelse() after the bqlock
has been acquired so that we may remove ourself from the free-list.
- Provide a bremfreef() function to immediately remove a buf from a
free-list for use only by NFS. This is done because the nfsclient code
overloads the b_freelist queue for its own async. io queue.
- Simplify the numfreebuffers accounting by removing a switch statement
that executed the same code in every possible case.
- getnewbuf() can encounter locked bufs on free-lists once Giant is removed.
Remove a panic associated with this condition and delay asserts that
inspect the buf until after it is locked.
Reviewed by: phk
Sponsored by: Isilon Systems, Inc.
away, instead only exit storming mode when an interrupt stops firing long
enough for the ithread to exit the loop and go back to sleep.
Tested by: macrus (cruder version)
Don't grab Giant in the upper syscall/wrapper code
NET_LOCK_GIANT in the socket code (sockets/fifos).
mtx_lock(&Giant) in the vnode code.
mtx_lock(&Giant) in the opencrypto code. (This may actually not be
needed, but better safe than sorry).
Devfs grabs Giant if the driver is marked as needing Giant.
Don't grab Giant in the upper syscall/wrapper code
NET_LOCK_GIANT in the socket code (sockets/fifos).
mtx_lock(&Giant) in the vnode code.
Devfs grabs Giant if the driver is marked as needing Giant.
- Have TS_ZOMBIE ttys return POLLHUP instead of POLLERR
- Remove unneeded POLLWRNORM (old bug)
- TS_ZOMBIE ttys will set POLLIN and POLLRDNORM
- Do not call selrecord in TS_ZOMBIE ttys
PR: kern/73821
Reviewed by: bde
MFC after: 4 weeks
a storm is detected, enter "storming" mode which throttles the interrupt
source such that the handlers are run once every clock tick. Previously
we allowed a full set of storm_threshold interations through the handler
before going back to sleep. Also, this currently will intentionally exit
storming mode once a second to see if the storm has passed.
Tested by: marcus
Discussed with: bde
