Instead of caching the ucred reference, just go ahead and eat the
decerement and increment of the refcount. Now that Giant is pushed down
into crfree(), we no longer have to get Giant in the common case. In the
case when we are actually free'ing the ucred, we would normally free it on
the next kernel entry, so the cost there is not new, just in a different
place. This also removse td_cache_ucred from struct thread. This is
still only done #ifdef DIAGNOSTIC.
Tested on: i386, alpha
a bit before handing it over to the OS. I occasionally have 11
segments with several 8K or so fragments depending on nvram settings and
what I have done under loader(8) before booting. This needs to be
revisited.
a language feature that I do not know about. gcc is complaining about
a left shift >= sizeof type, even when shifting a (cast) 64 bit type left
by 43 bits.
lose if a process is preempted while pmap is temporarily switched to
another pmap.
* For SMP, drop the high-fp state when a thread is switched away from
so that if another cpu resumes that thread, it doesn't have to play
games with IPI to get ahold of the correct register values.
* Don't call ast() from interrupt() - if we switch, then we will miss
writing cr.eoi which will prevent the current cpu from receiving
interrupts until the current thread is resumed. The call to ast()
happens magically in exception_restore where it is safe.
* Add DDB 'show irq' command to examine interrupt hardware state.
* Use ptc.g instead of ptc.l so that TLB shootdowns are broadcast to the
coherence domain.
* Use smp_rendezvous for pmap_invalidate_all to ensure it happens on all
cpus.
* Dike out a DIAGNOSTIC printf which didn't compile.
* Protect the internals of pmap_install with cpu_critical_enter/exit.
* Move the section which manipulates ia64_pal_base to after cninit() so
that we don't risk printing anything before we have a console.
* Don't call ia64_probe_sapics() for a SKI build. This should really
be dependant on ACPICA being present or something.
In order to determine what to page out, the vm_daemon checks
reference bits on all pages belonging to all processes. Unfortunately,
the algorithm used reacted badly with shared pages; each shared page
would be checked once per process sharing it; this caused an O(N^2)
growth of tlb invalidations. The algorithm has been changed so that
each page will be checked only 16 times.
Prior to this change, a fork/sleepbomb of 1300 processes could cause
the vm_daemon to take over 60 seconds to complete, effectively
freezing the system for that time period. With this change
in place, the vm_daemon completes in less than a second. Any system
with hundreds of processes sharing pages should benefit from this change.
Note that the vm_daemon is only run when the system is under extreme
memory pressure. It is likely that many people with loaded systems saw
no symptoms of this problem until they reached the point where swapping
began.
Special thanks go to dillon, peter, and Chuck Cranor, who helped me
get up to speed with vm internals.
PR: 33542, 20393
Reviewed by: dillon
MFC after: 1 week
While in userland, keep the thread's ucred reference in a shadow
field so that the usual place to store it is NULL.
If DIAGNOSTIC is not set, the thread ucred is kept valid until the next
kernel entry, at which time it is checked against the process cred
and possibly corrected. Produces a BIG speedup in
kernels with INVARIANTS set. (A previous commit corrected it
for the non INVARIANTS case already)
Reviewed by: dillon@freebsd.org
this is a low-functionality change that changes the kernel to access the main
thread of a process via the linked list of threads rather than
assuming that it is embedded in the process. It IS still embeded there
but remove all teh code that assumes that in preparation for the next commit
which will actually move it out.
Reviewed by: peter@freebsd.org, gallatin@cs.duke.edu, benno rice,
