and can lead to two threads being granted exclusive access. Check that no one
has the same lock in exclusive mode before proceeding to acquire it.
The LK_WANT_EXCL and LK_WANT_UPGRADE bits act as mini-locks and can block
other threads. Normally this is not a problem since the mini locks are
upgraded to full locks and the release of the locks will unblock the other
threads. However if a thread reset the bits without obtaining a full lock
other threads are not awoken. Add missing wakeups for these cases.
PR: kern/69964
Submitted by: Stephan Uphoff <ups at tree dot com>
Very good catch by: Stephan Uphoff <ups at tree dot com>
address of the dirhash, rather than the first sizeof(struct dirhash
*) bytes of the structure (which, thankfully, seem to be constant).
Submitted by: Ted Unangst <tedu@zeitbombe.org>
MFC after: 2 weeks
- include <machine/../linux32/linux.h> instead of <machine/../linux/linux.h>
if building with the COMPAT_LINUX32 option.
- make minimal changes to the i386 linprocfs_docpuinfo() function to support
amd64. We return a fake CPU family of 6 for now.
with the COMPAT_LINUX32 option. This is largely based on the i386 MD Linux
emulations bits, but also builds on the 32-bit FreeBSD and generic IA-32
binary emulation work.
Some of this is still a little rough around the edges, and will need to be
revisited before 32-bit and 64-bit Linux emulation support can coexist in
the same kernel.
on AMD64, and the general case where the emulated platform has different
size pointers than we use natively:
- declare certain structure members as l_uintptr_t and use the new PTRIN
and PTROUT macros to convert to and from native pointers.
- declare some structures __packed on amd64 when the layout would differ
from that used on i386.
- include <machine/../linux32/linux.h> instead of <machine/../linux/linux.h>
if compiling with COMPAT_LINUX32. This will need to be revisited before
32-bit and 64-bit Linux emulation support can coexist in the same kernel.
- other small scattered changes.
This should be a no-op on i386 and Alpha.
"debug.mpsafevm" results in (almost) Giant-free execution of zero-fill
page faults. (Giant is held only briefly, just long enough to determine
if there is a vnode backing the faulting address.)
Also, condition the acquisition and release of Giant around calls to
pmap_remove() on "debug.mpsafevm".
The effect on performance is significant. On my dual Opteron, I see a
3.6% reduction in "buildworld" time.
- Use atomic operations to update several counters in vm_fault().
before dereferencing sotounpcb() and checking its value, as so_pcb
is protected by protocol locking, not subsystem locking. This
prevents races during close() by one thread and use of ths socket
in another.
unp_bind() now assert the UNP lock, and uipc_bind() now acquires
the lock around calls to unp_bind().
wait for system wires to disappear, do so (much more trivially) by
instead only checking for system wires of user maps and not kernel maps.
Alternative by: tor
Reviewed by: alc
- pipespace is now able to resize non-empty pipes; this allows
for many more resizing opportunities
- Backing is no longer pre-allocated for the reverse direction
of pipes. This direction is rarely (if ever) used, so this cuts the
amount of map space allocated to a pipe in half.
- Pipe growth is now much more dynamic; a pipe will now grow when
the total amount of data it contains and the size of the write are
larger than the size of pipe. Previously, only individual writes greater
than the size of the pipe would cause growth.
- In low memory situations, pipes will now shrink during both read
and write operations, where possible. Once the memory shortage
ends, the growth code will cause these pipes to grow back to an appropriate
size.
- If the full PIPE_SIZE allocation fails when a new pipe is created, the
allocation will be retried with SMALL_PIPE_SIZE. This helps to deal
with the situation of a fragmented map after a low memory period has
ended.
- Minor documentation + code changes to support the above.
In total, these changes increase the total number of pipes that
can be allocated simultaneously, drastically reducing the chances that
pipe allocation will fail.
Performance appears unchanged due to dynamic resizing.
for EBus, ISA and PCI, by compiling ofw_isa.c and ofw_pci_if.m unconditio-
nally. The correct way is to rewrite OF_decode_addr() in ofw_machdep.c in
a bus-neutral way. That's certainly possible but we unfortunately didn't
make it for FreeBSD 5.3.
Approved by: tmm
contained "sanity" checks that could be violated if another CPU modified
the pmap between the emulation trap and locking the pmap in
pmap_emulate_reference(). As a result, the pte could be inconsistent
with the access that caused the emulation trap. In such cases,
pmap_emulate_reference() now flushes the current CPU's TLB entry and
returns.
- Make pmap_changebit() an inline function, reducing object code size.
