vtryrecycle(). We could sometimes get into situations where two threads
could try to recycle the same vnode before this.
- vtryrecycle() is now responsible for returning the vnode to the free list
if it fails and someone else hasn't done it.
- Make a new function vfreehead() which moves a vnode to the head of the
free list and use it in vgone() to clean up that code a bit.
Sponsored by: Isilon Systems, Inc.
Reported by: pho, kkenn
due to a change made in revision 1.284 of sys/kern/kern_sig.c in August
2004 which made ptracestop() return with the process still locked.
Submitted by: Mauritz Sundell
MFC After: 3 days
mutexes, which offers lower overhead on both UP and SMP. When allocating
from or freeing to the per-cpu cache, without INVARIANTS enabled, we now
no longer perform any mutex operations, which offers a 1%-3% performance
improvement in a variety of micro-benchmarks. We rely on critical
sections to prevent (a) preemption resulting in reentrant access to UMA on
a single CPU, and (b) migration of the thread during access. In the event
we need to go back to the zone for a new bucket, we release the critical
section to acquire the global zone mutex, and must re-acquire the critical
section and re-evaluate which cache we are accessing in case migration has
occured, or circumstances have changed in the current cache.
Per-CPU cache statistics are now gathered lock-free by the sysctl, which
can result in small races in statistics reporting for caches.
Reviewed by: bmilekic, jeff (somewhat)
Tested by: rwatson, kris, gnn, scottl, mike at sentex dot net, others
theoretically unload pci bridges or pci drivers. It will also allow
detach to work if one needed to detach a subtree.
This is inspired by looking at the p4 commits from bms to his 5.4
tree, but I didn't look at the final results.
/usr/src/sbin/ipf/ipftest/../../../sys/contrib/ipfilter/netinet/ip_frag.c: In function `fr_ipid_newfrag':
/usr/src/sbin/ipf/ipftest/../../../sys/contrib/ipfilter/netinet/ip_frag.c:397: warning: cast to pointer from integer of different size
/usr/src/sbin/ipf/ipftest/../../../sys/contrib/ipfilter/netinet/ip_frag.c: In function `fr_ipid_knownfrag':
/usr/src/sbin/ipf/ipftest/../../../sys/contrib/ipfilter/netinet/ip_frag.c:582: warning: cast from pointer to integer of different size
for the VGA I/O or memory ranges, when it's not within the default
ranges decoded by the bridge. When allocation for VGA addresses is
attempted, check that the bridge has the VGA Enable bit set before
allowing it.
As such, newbusified VGA drivers can allocate their resources when
the VGA adapter is behind a PCI-to-PCI bridge.
Reviewed by: imp@, jhb@
Only allow a process to use the x86 RDPMC instruction if it has
allocated and attached a PMC to itself.
Inform the MD layer of the "pseudo context switch out" that needs
to be done when the last thread of a process is exiting.
Move crc32() and crc32_raw() from the latter to the former. Move
the declaration of crc32_tab[] to <sys/libkern.h> as well.
Pointed out by: bde@
Tested on: ia64, sparc64
CRC logic to a new function: crc32_raw() that obtains the initial
CRC value as well as leaves any post-processing to the caller. As
such, it can be used when the initial CRC value is not ~0U or when
the final CRC value does need to be inverted (bitwise). It also
means that crc32_raw() can be called repeatedly when the data is
not available as a single block, such as for scatter/gather lists
and the likes.
Avoid the additional call overhead incured by the refactoring by
moving the implementation off crc32() to sys/systm.h and making it
inlinable. Since crc32_raw() is itself trivial and since it may
be used in loops that iterate over fragments, having it available
for inlining can be beneficial. Hence, move its implementation
to sys/systm.h as well.
Keep the original implementation of crc32() in libkern/crc32.c for
documentation purposes (as a comment of course).
Triggered by: Jose M Rodriguez (josemi at freebsd dot jazztel dot es)
Discussed on: current@
Tested on: amd64, ia64 (BVO having GPT partitions)
Jargon file candidate: BVO = By Virtue Of :-)
fact that access to RR0 does not need a prior write to the register
index because the index always reverts to 0 after the indexed register
has been accessed.
Typically when a RR or WR is to accessed, one programs the index (which
is a write to the control register), followed by a read or write to the
actual indexed register (a read pr write to the same control register).
When this non-atomic sequence is interrupted after having written the
index and low-level console I/O is done in that situation, the write to
program the index will actually write to the indexed register and nuke
state. This almost always yields a wedge.
By not programming the index register and instead just reading from RR0,
the worst case scenario is non-fatal. For if we don't actually read from
RR0 but some other register we get an invalid status, which may lead us
to conclude that the transit data register is empty when it's not or that
the receive data register contains data when it doesn't. Hence, we may
lose an output character or get a sporadic input character, but given
the situation this is a non-issue.
Full serialization is not possible due to the fact that this code needs
to work from DDB and before mutex initialization has happened.
In collaboration with: kris@, marius@
Tested by: kris@
MFC after: 1 day
X-MFC: 5.4-RELEASE candidate
the MNT_RDONLY flag if the "ro" option was passed in from userland, and
clears it otherwise. In the diskless case, the MNT_RDONLY flag is already
set when this code is reached, but there are no mount options, so it was
incorrectly cleared. Change the logic so the MNT_RDONLY flag is set if the
"ro" option was specified, and left alone otherwise.
Note that the NFS code will still happily let you mount a filesystem RW
even if the server exports it RO. I'm not sure how to fix that.
caller will be interested in the actual data contents of a vnode after
a successful lookup. This intended to help deal with lifetime issues
for device cloning and to alert autofs when filesystems need to be
mounted.
