access. The old scheduler had a global freelist which caused a
cache crisis with multiple host threads trying to schedule a virtual
CPU simultaneously.
The rump scheduler is different from a normal thread scheduler, so
it has different requirements. First, we schedule a CPU for a
thread (which we get from the host scheduler) instead of scheduling
a thread onto a CPU. Second, scheduling points are at every
entry/exit to/from the rump kernel, including (but not limited to)
syscall entry points and hypercalls. This means scheduling happens
a lot more frequently than in a normal kernel.
For every lwp, cache the previously used CPU. When scheduling,
attempt to reuse the same CPU. If we get it, we can use it directly
without any memory barriers or expensive locks. If the CPU is
taken, migrate. Use a lock/wait only in the slowpath. Be very
wary of walking the entire CPU array because that does not lead to
a happy cacher.
The migration algorithm could probably benefit from improved
heuristics and tuning. Even as such, with the new scheduler an
application which has two threads making rlimit syscalls in a tight
loop experiences almost 400% speedup. The exact speedup is difficult
to pinpoint, though, since the old scheduler caused very jittery
results due to cache contention. Also, the rump version is now
70% faster than the counterpart which calls the host kernel.
to do two things:
1) properly set "recycle?" in inactive
2) easily check if we are renaming a removed vnode. without the
check, it was possible to enter a dirent in the file system for
a removed (and hence scheduled to be vcleaned) vnode. this would
lead to the succesful vget() of a clean vnode. the use of the
cleaned vnode was, however, less succesful, except for purposes
of crashing.
string, in case the format string contains printf conversions
assembled from escape sequences.
A better approach might be to adjust the unescape logic to avoid
generating printf conversions (e.g. convert \x25 to %% instead of %)
but that's somewhat problematic and it's not really worth taking the
trouble.
Running valid_format() only after unescaping would also be somewhat
tidier but makes printing the invalid format string problematic,
because the unescape logic runs in place.
None of these cases are really worth worrying about in detail, but now
at least they don't result in SIGSEGV.
Related to PR 43355.
formats.
Also, accept %a and %A, which are new since this logic was last updated,
and also allow %F even though it's not functionally different from %f.
Document these additions and bump date of man page.
Fixes PR 43355.
trees, because it can race with the libsa/libkern/etc. makefiles' own
cleandir rules. I think I've found all of the uses of the offending idiom...
Closes PR 43360.
we don't need to include pcivar.h in the module. pcivar.h tries to pull
in machine/pci_machdep.h which doesn't exist on all machine/architecture
combos. Keeping track and building the module only for those that work
would have been a maintenance headache; this change allows us to build
the module on all systems, regardless of whether the system has pci
support or not.
This prevents converting "+3" into "-k4.1" in places where getopt
won't recognize it, which in turn prevents silly error messages and
lossage trying to sort files whose names begin with +. PR 43358.
the value before the call (yea, changing relookup would probably
be smart, but other file systems already initialize vpp, so I'm
letting someone else experiment with tylenol od).
