as it could be and can do with some more cleanup. Currently its under
options LAZY_SWITCH. What this does is avoid %cr3 reloads for short
context switches that do not involve another user process. ie: we can
take an interrupt, switch to a kthread and return to the user without
explicitly flushing the tlb. However, this isn't as exciting as it could
be, the interrupt overhead is still high and too much blocks on Giant
still. There are some debug sysctls, for stats and for an on/off switch.
The main problem with doing this has been "what if the process that you're
running on exits while we're borrowing its address space?" - in this case
we use an IPI to give it a kick when we're about to reclaim the pmap.
Its not compiled in unless you add the LAZY_SWITCH option. I want to fix a
few more things and get some more feedback before turning it on by default.
This is NOT a replacement for Bosko's lazy interrupt stuff. This was more
meant for the kthread case, while his was for interrupts. Mine helps a
little for interrupts, but his helps a lot more.
The stats are enabled with options SWTCH_OPTIM_STATS - this has been a
pseudo-option for years, I just added a bunch of stuff to it.
One non-trivial change was to select a new thread before calling
cpu_switch() in the first place. This allows us to catch the silly
case of doing a cpu_switch() to the current process. This happens
uncomfortably often. This simplifies a bit of the asm code in cpu_switch
(no longer have to call choosethread() in the middle). This has been
implemented on i386 and (thanks to jake) sparc64. The others will come
soon. This is actually seperate to the lazy switch stuff.
Glanced at by: jake, jhb
a pointer that is in user space. It will be used as the basic primitive
for a kernel supported user space lock implementation.
- Implement this function in x86's support.s
- Provide stubs that return -1 in all other architectures. Implementations
will follow along shortly.
Reviewed by: jake
a follow on commit to kern_sig.c
- signotify() now operates on a thread since unmasked pending signals are
stored in the thread.
- PS_NEEDSIGCHK moves to TDF_NEEDSIGCHK.
- Change all consumers to pass in a thread.
Right now this does not cause any functional changes but it will be important
later when signals can be delivered to specific threads.
kernel opition 'options PAE'. This will only work with device drivers which
either use busdma, or are able to handle 64 bit physical addresses.
Thanks to Lanny Baron from FreeBSD Systems for the loan of a test machine
with 6 gigs of ram.
Sponsored by: DARPA, Network Associates Laboratories, FreeBSD Systems
accessing an alternate address space this causes 1 page table page at
a time to be mapped in, rather than using the recursive mapping technique
to map in an entire alternate address space. The recursive mapping
technique changes large portions of the address space and requires global
tlb flushes, which seem to cause problems when PAE is enabled. This will
also allow IPIs to be avoided when mapping in new page table pages using
the same technique as is used for pmap_copy_page and pmap_zero_page.
Sponsored by: DARPA, Network Associates Laboratories
This keeps the logical cpu's halted in the idle loop. By default
the logical cpu's are halted at startup. It is also possible to
halt any cpu in the idle loop now using machdep.hlt_cpus.
Examples of how to use this:
machdep.hlt_cpus=1 halt cpu0
machdep.hlt_cpus=2 halt cpu1
machdep.hlt_cpus=4 halt cpu2
machdep.hlt_cpus=3 halt cpu0,cpu1
Reviewed by: jhb, peter
1) Its critical for HTT. There's less foot-shooting opportunity.
2) I've seen significant improvements in interactive response to commands
over ssh sessions. I assume this is less lock contention.
3) As incentive to finish the idle cpu IPI wakeup stuff.
4) The machine on my desk was blowing hot air in my general direction
because somebody forgot to turn the hlt on, and it saves 50 watts per
cpu..
The machdep.cpu_idle_hlt sysctl is still available, but now the default
is the same as on UP kernels.
where physical addresses larger than virtual addresses, such as i386s
with PAE.
- Use this to represent physical addresses in the MI vm system and in the
i386 pmap code. This also changes the paddr parameter to d_mmap_t.
- Fix printf formats to handle physical addresses >4G in the i386 memory
detection code, and due to kvtop returning vm_paddr_t instead of u_long.
Note that this is a name change only; vm_paddr_t is still the same as
vm_offset_t on all currently supported platforms.
Sponsored by: DARPA, Network Associates Laboratories
Discussed with: re, phk (cdevsw change)
doesn't do it. This fixes all known causes of "Context switches not
allowed in the debugger" in mi_switch(). The main cause was trap_fatal()
calling kdb_trap() with interrupts enabled. Switching to ithreads for
interrupt handling then made fatal traps more fatal and harder to debug.
The problem was limited in -current because most interrupt handlers are
blocked by Giant, but it occurred almost deterministically for me because
my clock interrupt handlers are non-fast and not blocked by Giant.
in busdma tags. There are currently no tags shared accross
different drivers so this isn't needed at the moment, but it
will be required when we'll have a proper newbus method to get
the parent busdma tag.
4 bits. This reportedly fixes booting on the SW7500CW2. Much thanks to
the submitter for tracking this down!
Submitted by: Brian Buchanan <brian@ncircle.com>
Reviewed by: peter
MFC after: 3 days
are machine dependent because they are not required to update the tlb when
mappings are added or removed, and doing so is machine dependent.
In addition, an implementation may require that pages mapped with pmap_kenter
have a backing vm_page_t, which is not necessarily true of all physical
pages, and so may choose to pass the vm_page_t to pmap_kenter instead of the
physical address in order to make this requirement clear.
pmap_release.
- Merged pmap_release and pmap_release_free_page. When pmap_release is
called only the page directory page(s) can be left in the pmap pte object,
since all page table pages will have been freed by pmap_remove_pages and
pmap_remove. In addition, there can only be one reference to the pmap and
the page directory is wired, so the page(s) can never be busy. So all there
is to do is clear the magic mappings from the page directory and free the
page(s).
Sponsored by: DARPA, Network Associates Laboratories
The random value sometimes causes macro CLKF_USERMODE to return true
because PSL_VM bit is set and really shoudn't be, this causes statclock()
to execute in wrong path, and further breaks KSE code and kernel crashes
when executing threaded program.
check, mac_check_sysarch_ioperm(), permitting MAC security policy
modules to control access to these interfaces. Currently, they
protect access to IOPL on i386, and setting HAE on Alpha.
Additional checks might be required on other platforms to prevent
bypass of kernel security protections by unauthorized processes.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
branches:
Initialize struct cdevsw using C99 sparse initializtion and remove
all initializations to default values.
This patch is automatically generated and has been tested by compiling
LINT with all the fields in struct cdevsw in reverse order on alpha,
sparc64 and i386.
Approved by: re(scottl)
Fixed memory leak in the "nodevice" option implementation.
Use these instead of sed(1) in MD NOTES.
Use a single makefile (sys/conf/makeLINT.mk) to generate
LINT for all architectures. (Previous versions missed
the LINT dependency on Makefile, and i386 version also
missed the dependency on ${NOTES}.)
Fixed bugs in the previous NOTES conversion using the
"nodevice" token and sed(1):
- i386 LINT lost "device pst".
- pc98 LINT lost SC_*, MAXCONS and KBD_DISABLE_KEYMAP_LOAD
options, and got needless DPT_* options.
- Added nooptions PPC_DEBUG, PPC_PROBE_CHIPSET, KBD_INSTALL_CDEV
to sparc64 LINT so that it has a chance to config(8).
This basically returns us to where we were before.
for testing and setting the current and alternate address spaces.
- Changed PTDpde and APTDpde to arrays to support multiple page directory
pages.
ponsored by: DARPA, Network Associates Laboratories
- Get rid of the useless atop() / pmap_phys_address() detour. The
device mmap handlers must now give back the physical address
without atop()'ing it.
- Don't borrow the physical address of the mapping in the returned
int. Now we properly pass a vm_offset_t * and expect it to be
filled by the mmap handler when the mapping was successful. The
mmap handler must now return 0 when successful, any other value
is considered as an error. Previously, returning -1 was the only
way to fail. This change thus accidentally fixes some devices
which were bogusly returning errno constants which would have been
considered as addresses by the device pager.
- Garbage collect the poorly named pmap_phys_address() now that it's
no longer used.
- Convert all the d_mmap_t consumers to the new API.
I'm still not sure wheter we need a __FreeBSD_version bump for this,
since and we didn't guarantee API/ABI stability until 5.1-RELEASE.
Discussed with: alc, phk, jake
Reviewed by: peter
Compile-tested on: LINT (i386), GENERIC (alpha and sparc64)
Runtime-tested on: i386
- Changed VM_MAXUSER_ADDRESS to be defined in terms of PTDPTDI. In order for
assumptions about the recursive page table map to work it must be the base
of the recursive map. Any pte offset that's not NPTEPG will break these
assumptions.
Sponsored by: DARPA, Network Associates Laboratories
instead of allocating another page of kva and mapping it in again. This was
likely an oversight in revision 1.174 (cut and paste from pmap_pinit).
Discussed with: peter, tegge
Sponsored by: DARPA, Network Associates Laboratories
