work in, but we had it mapped read-only. While this has always been the
case, the PG_PS enable hack hid it and the apm bios code ended up taking
advantage of it.
This is so that we may grab the interlock while still holding the
sync_mtx. We have to VI_TRYLOCK() because in all other cases the lock
order runs the other way.
- If we don't meet any of the preconditions, reinsert the vp into the
list for the next second.
- We don't need to panic if we fail to sync here because each FSYNC
function handles this case. Removing this redundant code also
simplifies locking.
will not actually be set even though we're calling sosetopt. sosetopt
calls down to a single ctloutput function if the name or level is
implemented by a specific protocol.
Submitted by: pete@isilon.com
fail. Remove the panic from that case and document why it might fail.
- Document the reason for calling cache_purge() on a newly created vnode.
- In insmntque() order the operations so that we can call mtx_unlock()
one fewer times. This makes the code somewhat clearer as well.
- Add XXX comments in sched_sync() and vflush().
- In vget(), do not sleep while waiting for XLOCK to clear if LK_NOWAIT is
set.
- In vclean() we don't need to acquire a lock around a single TAILQ_FIRST
call. It's ok if we race here, the vinvalbuf will just do nothing.
- Increase the scope of the lock in vgonel() to reduce the number of lock
operations that are performed.
we release the mntvnode_mtx.
- Call vgonel() directly instead of going through vrecycle() since we own
the interlock now.
- Remove a few cases where we locked the interlock just so that we could
call VOP_UNLOCK with interlock held.
mntvnode_mtx.
- Use a local variable to store the results of the test to see if the
next vnode on the mount list has changed. This is so that we no longer
acess the vnode after we vput() it.
stack trace supplied by phk, I now understand what's going on here. The
check for VI_XLOCK stops us from calling vinvalbuf once the vnode has been
partially torn down in vclean(). It is not clear that this would cause
a problem. Document this in nfs_bio.c, which is where the other two
filesystems copied this code from.
I do not yet understand why, but apm *depended* on the fact that the old
PSE code caused the first 1MB of ram to be mapped read/write because it
was in the same 4MB page as the kernel text+data+bss blob.
If anybody ever tried DISABLE_PSE before, apm would not work.
If your cpu did not have PSE, apm would not work there either (eg: 486).
This bug has been around for a Very Long Time.
The Pentium-4-fix commits did not emulate this unintended side effect of
the PSE post-early-boot fixup, and thus apm blew up. I've added a hack to
emulate the bug until either apm is fixed or we set fire to our bridges.
This is bad though because it gives kernel mode code the opportunity
to accidently write to the first few megs of the general page pool
which is remapped at KERNBASE. It needs to be fixed properly.
that covers updates to the contents. Note this is separate from holding
a reference and/or locking the routing table itself.
Other/related changes:
o rtredirect loses the final parameter by which an rtentry reference
may be returned; this was never used and added unwarranted complexity
for locking.
o minor style cleanups to routing code (e.g. ansi-fy function decls)
o remove the logic to bump the refcnt on the parent of cloned routes,
we assume the parent will remain as long as the clone; doing this avoids
a circularity in locking during delete
o convert some timeouts to MPSAFE callouts
Notes:
1. rt_mtx in struct rtentry is guarded by #ifdef _KERNEL as user-level
applications cannot/do-no know about mutex's. Doing this requires
that the mutex be the last element in the structure. A better solution
is to introduce an externalized version of struct rtentry but this is
a major task because of the intertwining of rtentry and other data
structures that are visible to user applications.
2. There are known LOR's that are expected to go away with forthcoming
work to eliminate many held references. If not these will be resolved
prior to release.
3. ATM changes are untested.
Sponsored by: FreeBSD Foundation
Obtained from: BSD/OS (partly)
A small helper function pmap_is_prefaultable() is added. This function
encapsulate the few lines of pmap_prefault() that actually vary from
machine to machine. Note: pmap_is_prefaultable() and pmap_mincore() have
much in common. Going forward, it's worth considering their merger.
been widely deploy and that's causing us a lot of pain. Back out the
last commit for a few weeks so that we can lessen the support load in
current@ asking why they can't build kernels anymore. Instructions in
UPDATING have been updated, but this should be more effective.
Revert the reverting: November 1st, 2003
quantities on every other architecture.) This change is required in order
to move pmap_prefault() out of the pmap and into the machine-independent
layer.
any queued packets for the isr, process those packets before the newly
submitted packet, maintaining ordering of all packets being delivered
to the netisr. Remove the bypass counter since we don't bypass anymore.
Leave the comment about possible problems and options since later
performance optimization may change the strategy for addressing ordering
problems here.
Specifically, this maintains the strong isr ordering guarantee; additional
parallelism and lower latency may be possible by moving to weaker
guarantees (per-interface, for example). We will probably at some point
also want to remove the one instance netisr dispatch limit currently
enforced by a mutex, but it's not clear that's 100% safe yet, even in
the netperf branch.
Reviewed by: sam, others
o move route_cb to be private to rtsock.c
o replace global static route_proto by locals
o eliminate global #define shorthands for info references
o remove some register decls
o ansi-fy function decls
o move items to be close in scope to their usage
o add rt_dispatch function for dispatching the actual message
o cleanup tangled logic for doing all-but-me msg send
Support by: FreeBSD Foundation
RTF_STATIC routes. Do not check for RTF_HOST so as to avoid being DoSed
when an RTF_GENMASK route exists in the table.
Add a more verbose comment about exactly what this code does.
Submitted by: ru
frame marker) and the syscall stub frame info in the trap frame.
Previously we stored the stub frame info in (rp,pfs) and the
caller frame info in (iip,cfm). This ends up being suboptimal
for the following reasons:
1. When we create a new context, such as for an execve(2), we had
to set the (rp,pfs) pair for the entry point when using the
syscall path out of the kernel but we need to set the (iip,cfm)
pair when we take the interrupt way out. This is mostly just
an inconsistency from the kernel's point of view, but an ugly
irregularity from gdb(1)'s point of view.
2. The getcontext(2) and setcontext(2) syscalls had to swap the
(rp,pfs) and (iip,cfm) pairs to make the context compatible
with one created purely in userland.
Swapping the (rp,pfs) and (iip,cfm) pairs is visible to signal
handlers that actually peek at the mcontext_t and to gdb(1).
Since this change is made for gdb(1) and we don't care about
signal handlers that peek at the mcontext_t because we're still
a tier 2 platform, this ABI breakage is academic at this moment
in time.
Note that there was no real reason to save the caller frame info
in (iip,cfm) and the stub frame info in (rp,pfs).
validating the offset within a given memory buffer before handing the
real work off to uiomove(9).
Use uiomove_frombuf in procfs to correct several issues with
integer arithmetic that could result in underflows/overflows. As a
side-effect, the code is significantly simplified.
Add additional sanity checks when computing a memory allocation size
in pfs_read.
Submitted by: rwatson (original uiomove_frombuf -- bugs are mine :-)
Reported by: Joost Pol <joost@pine.nl> (integer underflows/overflows)
