than as one-off hacks in various other parts of the kernel:
- Add a function maybe_preempt() that is called from sched_add() to
determine if a thread about to be added to a run queue should be
preempted to directly. If it is not safe to preempt or if the new
thread does not have a high enough priority, then the function returns
false and sched_add() adds the thread to the run queue. If the thread
should be preempted to but the current thread is in a nested critical
section, then the flag TDF_OWEPREEMPT is set and the thread is added
to the run queue. Otherwise, mi_switch() is called immediately and the
thread is never added to the run queue since it is switch to directly.
When exiting an outermost critical section, if TDF_OWEPREEMPT is set,
then clear it and call mi_switch() to perform the deferred preemption.
- Remove explicit preemption from ithread_schedule() as calling
setrunqueue() now does all the correct work. This also removes the
do_switch argument from ithread_schedule().
- Do not use the manual preemption code in mtx_unlock if the architecture
supports native preemption.
- Don't call mi_switch() in a loop during shutdown to give ithreads a
chance to run if the architecture supports native preemption since
the ithreads will just preempt DELAY().
- Don't call mi_switch() from the page zeroing idle thread for
architectures that support native preemption as it is unnecessary.
- Native preemption is enabled on the same archs that supported ithread
preemption, namely alpha, i386, and amd64.
This change should largely be a NOP for the default case as committed
except that we will do fewer context switches in a few cases and will
avoid the run queues completely when preempting.
Approved by: scottl (with his re@ hat)
than a a stack-limited list. This removes the artifical limit on s/g list
size.
cvs: ----------------------------------------------------------------------
Ultra2 users may want to set OFWCONS_POLL_HZ to a value of '20'.
I have left default value at '4' as higher values can consume a more
than is acceptable amount of CPU, and we don't have a consensus yet
what is an optimal value.
Submitted by: Pyun YongHyeon <yongari@kt-is.co.kr>
its primary use is for the FEPS/FAS366 SCSI found in Sun Ultra 1e and 2
machines. Once the pci front-end is ported, this driver can replace the
amd(4) driver.
The code as-is is fairly stable. I've disabled tagged-queueing until I can
figure out a corruption bug related to it. I'm importing it now so that
people with these machines can (finally) stop netbooting and report bugs
before 5.3.
mbuma is an Mbuf & Cluster allocator built on top of a number of
extensions to the UMA framework, all included herein.
Extensions to UMA worth noting:
- Better layering between slab <-> zone caches; introduce
Keg structure which splits off slab cache away from the
zone structure and allows multiple zones to be stacked
on top of a single Keg (single type of slab cache);
perhaps we should look into defining a subset API on
top of the Keg for special use by malloc(9),
for example.
- UMA_ZONE_REFCNT zones can now be added, and reference
counters automagically allocated for them within the end
of the associated slab structures. uma_find_refcnt()
does a kextract to fetch the slab struct reference from
the underlying page, and lookup the corresponding refcnt.
mbuma things worth noting:
- integrates mbuf & cluster allocations with extended UMA
and provides caches for commonly-allocated items; defines
several zones (two primary, one secondary) and two kegs.
- change up certain code paths that always used to do:
m_get() + m_clget() to instead just use m_getcl() and
try to take advantage of the newly defined secondary
Packet zone.
- netstat(1) and systat(1) quickly hacked up to do basic
stat reporting but additional stats work needs to be
done once some other details within UMA have been taken
care of and it becomes clearer to how stats will work
within the modified framework.
From the user perspective, one implication is that the
NMBCLUSTERS compile-time option is no longer used. The
maximum number of clusters is still capped off according
to maxusers, but it can be made unlimited by setting
the kern.ipc.nmbclusters boot-time tunable to zero.
Work should be done to write an appropriate sysctl
handler allowing dynamic tuning of kern.ipc.nmbclusters
at runtime.
Additional things worth noting/known issues (READ):
- One report of 'ips' (ServeRAID) driver acting really
slow in conjunction with mbuma. Need more data.
Latest report is that ips is equally sucking with
and without mbuma.
- Giant leak in NFS code sometimes occurs, can't
reproduce but currently analyzing; brueffer is
able to reproduce but THIS IS NOT an mbuma-specific
problem and currently occurs even WITHOUT mbuma.
- Issues in network locking: there is at least one
code path in the rip code where one or more locks
are acquired and we end up in m_prepend() with
M_WAITOK, which causes WITNESS to whine from within
UMA. Current temporary solution: force all UMA
allocations to be M_NOWAIT from within UMA for now
to avoid deadlocks unless WITNESS is defined and we
can determine with certainty that we're not holding
any locks when we're M_WAITOK.
- I've seen at least one weird socketbuffer empty-but-
mbuf-still-attached panic. I don't believe this
to be related to mbuma but please keep your eyes
open, turn on debugging, and capture crash dumps.
This change removes more code than it adds.
A paper is available detailing the change and considering
various performance issues, it was presented at BSDCan2004:
http://www.unixdaemons.com/~bmilekic/netbuf_bmilekic.pdf
Please read the paper for Future Work and implementation
details, as well as credits.
Testing and Debugging:
rwatson,
brueffer,
Ketrien I. Saihr-Kesenchedra,
...
Reviewed by: Lots of people (for different parts)
struct vmspace is freed from cpu_sched_exit() to pmap_release().
This has the advantage of being able to rely on MI code to decide
when a free should occur, instead of having to inspect the reference
count ourselves.
At the same time, turn the per-CPU vmspace pointer into a pmap pointer,
so that pmap_release() can deal with pmaps exclusively.
Reviewed (and embrassing bug spotted) by: jake
to <sys/gmon.h>. Cleaned them up a little by not attempting to ifdef
for incomplete and out of date support for GUPROF in userland, as in
the sparc64 version.
elf_reloc() backends for two reasons. First, to support the possibility
of there being two elf linkers in the kernel (eg: amd64), and second, to
pass the relocbase explicitly (for relocating .o format kld files).
"options OFW_NEWPCI").
This is a bit overdue, the new sparc64 OFW PCI code which is
meant to replace the old one is in place for 10 months and
enabled by default in GENERIC for 8 months. FreeBSD 5.2 and
5.2.1 also shipped with the new code enabled by default.
- Some minor clean-up, e.g. remove functions that encapsulated
the #ifdefs for OFW_NEWPCI, remove unused resp. no longer
required includes, etc.
Approved by: tmm, no objections on freebsd-sparc64
and type for printing info about the device that didn't probe from child, not
parent.
This fixes a panic on systems where not yet supported devices hang off of the
nexus, e.g. on E450.
Reported by: joerg
- Remove second license, the first was not that different and should be
fine.
- Add nexus_attach(), and do not perform its task in nexus_probe() any
more.
- Remove nexus_write_ivar(), since it was quite pointless.
- Remove superfluous devinfo members.
- Clean up some comments, minor style issues and prototypes.
bridges, the EBus bridge has resource ranges it claims exclusively to
map its children into in its BARs. Hence, we need to allocate these
completely and manage them for the children, instead of just passing
allocations through to the PCI layer as we did before.
While being there, split ebus_probe(), which did also contain code
normally belonging into the attach method, into ebus_probe() and
ebus_attach(), and perform some minor cleanups.
- Fix some comments; remove numerous superfluous or outdated ones.
- Correctly pass on the requesting device when handing requests up
to the parent bus.
- Use the complete device name, including unit number, to build the
IOMMU instance name.
- Inline a function that was only used once, and was trivial.
phandle_t. Since both are typedefed to unsigned int, this is more
or less cosmetic.
- Fix the code that determines whether a creator instance was used
for firmware output (and should not be blanked on initialization).
Since r1.2 of dev/fb/creator.c, this consisted comparing a handle of
an instance of a package with a handle of the package itself.
Use the test from r1.1, which utilizes OF_instance_to_package().
Submitted by: Marius Strobl <marius@alchemy.franken.de>
