allocation fails and pv entries are reclaimed, there may be an unused pv
entry in a pv chunk that survived the reclamation. However, previously,
after reclamation, get_pv_entry() did not look for an unused pv entry in
a surviving pv chunk; it simply retried the page allocation. Now, it
does look for an unused pv entry before retrying the page allocation.
Note: This only applies to RELENG_7. Earlier branches use a different
pv entry allocator.
MFC after: 6 weeks
since the branch caches on at least Athlon XP through Athlon 64 CPU's
don't understand such instructions and guarantee a cache miss taking
at least 10 cycles. Use the documented workaround "ret $0" instead
("nop; ret" also works, but "ret $0" is probably faster on old CPUs).
Normal code (even asm code) doesn't branch to "ret", since there is
usually some cleanup to do, but the __mcount, .mcount and .mexitcount
entry points were optimized too well to have the minimum number of
instructions (3 instructions each if profiling is not enabled) and
they did this. I didn't see a significant number of cache misses for
.mexitcount, but for the shared "ret" for __mcount and .mcount I
observed cache misses costing 26 cycles each. For a send(2) syscall
that makes about 70 function calls, the cost of these cache misses
alone increased the syscall time from about 4000 cycles to about 7000
cycles. 4000 is for a profiling (GUPROF) kernel with profiling disabled;
after this fix, configuring profiling only costs about 600 cycles in the
4000, which is consistent with almost perfect branch prediction in the
mcounting calls.
unused except to obfuscate disassemblies. -mprofiler-epilogue is
currently with gcc-4 (it does too little), but -finstrument-functions
is broken in a different way (it does too much).
amd64 version: meger whitespace fixes from i386 version.
- On amd64, just assume type #1 is always used. PCI 2.0 mandated
deprecated type #2 and required type #1 for all future bridges which
was well before amd64 existed.
- For i386, ignore whatever value was in 0xcf8 before testing for type #1
and instead rely on the other tests to determine if type #1 works. Some
newer machines leave garbage in 0xcf8 during boot and as a result the
kernel doesn't find PCI at all (which greatly confuses ACPI which expects
PCI to exist when PCI busses are in the namespace).
MFC after: 3 days
Discussed with: scottl
Currently, Giant is not too much contented so that it is ok to treact it
like any other mutexes.
Please don't forget to update your own custom config kernel files.
Approved by: cognet, marcel (maintainers of arches where option is
not enabled at the moment)
routine. It is not needed as the existing tests for segment coalescing
already handle bounced addresses and it prevents legal segment coalescing
in certain edge cases.
MFC after: 1 week
Reviewed by: scottl
include the ithread scheduling step. Without this, a preemption might
occur in between the interrupt getting masked and the ithread getting
scheduled. Since the interrupt handler runs in the context of curthread,
the scheudler might see it as having a such a low priority on a busy system
that it doesn't get to run for a _long_ time, leaving the interrupt stranded
in a disabled state. The only way that the preemption can happen is by
a fast/filter handler triggering a schduling event earlier in the handler,
so this problem can only happen for cases where an interrupt is being
shared by both a fast/filter handler and an ithread handler. Unfortunately,
it seems to be common for this sharing to happen with network and USB
devices, for example. This fixes many of the mysterious TCP session
timeouts and NIC watchdogs that were being reported. Many thanks to Sam
Lefler for getting to the bottom of this problem.
Reviewed by: jhb, jeff, silby
First, a file is mmap(2)ed and then mlock(2)ed. Later, it is truncated.
Under "normal" circumstances, i.e., when the file is not mlock(2)ed, the
pages beyond the EOF are unmapped and freed. However, when the file is
mlock(2)ed, the pages beyond the EOF are unmapped but not freed because
they have a non-zero wire count. This can be a mistake. Specifically,
it is a mistake if the sole reason why the pages are wired is because of
wired, managed mappings. Previously, unmapping the pages destroys these
wired, managed mappings, but does not reduce the pages' wire count.
Consequently, when the file is unmapped, the pages are not unwired
because the wired mapping has been destroyed. Moreover, when the vm
object is finally destroyed, the pages are leaked because they are still
wired. The fix is to reduce the pages' wired count by the number of
wired, managed mappings destroyed. To do this, I introduce a new pmap
function pmap_page_wired_mappings() that returns the number of managed
mappings to the given physical page that are wired, and I use this
function in vm_object_page_remove().
Reviewed by: tegge
MFC after: 6 weeks
- Populate the register values for the trapframe put on the stack by the
double fault handler.
- Teach DDB's trace routine to treat a double fault like other trap frames.
MFC after: 3 days
communicate that it relates to (is called by) thread_alloc()
o Add cpu_thread_free() which is called from thread_free()
to counter-act cpu_thread_alloc().
i386: Have cpu_thread_free() call cpu_thread_clean() to
preserve behaviour.
ia64: Have cpu_thread_free() call mtx_destroy() for the
mutex initialized in cpu_thread_alloc().
PR: ia64/118024
opposed to what process. Since threads by default have teh name of the
process unless over-written with more useful information, just print the
thread name instead.
This includes:
o mtree (for legal/intel_wpi)
o manpage for i386/amd64 archs
o module for i386/amd64 archs
o NOTES for i386/amd64 archs
Approved by: mlaier (comentor)
must be globally performed before calling any of the TLB invalidation
functions.
With one exception, on amd64, this requirement was already met. Fix this
one case. Also, as a clarification, change an existing atomic op into a
release. (Suggested by: jhb)
Reported and reviewed by: ups
MFC after: 3 days
silent NULL pointer dereference in the i386 and sparc64 pmap_pinit()
when the kmem_alloc_nofault() failed to allocate address space. Both
functions now return error instead of panicing or dereferencing NULL.
As consequence, vmspace_exec() and vmspace_unshare() returns the errno
int. struct vmspace arg was added to vm_forkproc() to avoid dealing
with failed allocation when most of the fork1() job is already done.
The kernel stack for the thread is now set up in the thread_alloc(),
that itself may return NULL. Also, allocation of the first process
thread is performed in the fork1() to properly deal with stack
allocation failure. proc_linkup() is separated into proc_linkup()
called from fork1(), and proc_linkup0(), that is used to set up the
kernel process (was known as swapper).
In collaboration with: Peter Holm
Reviewed by: jhb
warnings. Specifically, whenever vm_page_alloc(9) returned NULL to
get_pv_entry(), we issued a warning regardless of the number of pv
entries in use. (Note: The older pv entry allocator in RELENG_6 does
not have this problem.)
Reported by: Jeremy Chadwick
Eliminate the direct call to pagedaemon_wakeup() by get_pv_entry().
This was a holdover from earlier times when the page daemon was
responsible for the reclamation of pv entries.
MFC after: 5 days
refactored it to be a generic device.
Instead of being part of the standard kernel, there is now a 'nvram' device
for i386/amd64. It is in DEFAULTS like io and mem, and can be turned off
with 'nodevice nvram'. This matches the previous behavior when it was
first committed.
support machines having multiple independently numbered PCI domains
and don't support reenumeration without ambiguity amongst the
devices as seen by the OS and represented by PCI location strings.
This includes introducing a function pci_find_dbsf(9) which works
like pci_find_bsf(9) but additionally takes a domain number argument
and limiting pci_find_bsf(9) to only search devices in domain 0 (the
only domain in single-domain systems). Bge(4) and ofw_pcibus(4) are
changed to use pci_find_dbsf(9) instead of pci_find_bsf(9) in order
to no longer report false positives when searching for siblings and
dupe devices in the same domain respectively.
Along with this change the sole host-PCI bridge driver converted to
actually make use of PCI domain support is uninorth(4), the others
continue to use domain 0 only for now and need to be converted as
appropriate later on.
Note that this means that the format of the location strings as used
by pciconf(8) has been changed and that consumers of <sys/pciio.h>
potentially need to be recompiled.
Suggested by: jhb
Reviewed by: grehan, jhb, marcel
Approved by: re (kensmith), jhb (PCI maintainer hat)
ways:
(1) Cached pages are no longer kept in the object's resident page
splay tree and memq. Instead, they are kept in a separate per-object
splay tree of cached pages. However, access to this new per-object
splay tree is synchronized by the _free_ page queues lock, not to be
confused with the heavily contended page queues lock. Consequently, a
cached page can be reclaimed by vm_page_alloc(9) without acquiring the
object's lock or the page queues lock.
This solves a problem independently reported by tegge@ and Isilon.
Specifically, they observed the page daemon consuming a great deal of
CPU time because of pages bouncing back and forth between the cache
queue (PQ_CACHE) and the inactive queue (PQ_INACTIVE). The source of
this problem turned out to be a deadlock avoidance strategy employed
when selecting a cached page to reclaim in vm_page_select_cache().
However, the root cause was really that reclaiming a cached page
required the acquisition of an object lock while the page queues lock
was already held. Thus, this change addresses the problem at its
root, by eliminating the need to acquire the object's lock.
Moreover, keeping cached pages in the object's primary splay tree and
memq was, in effect, optimizing for the uncommon case. Cached pages
are reclaimed far, far more often than they are reactivated. Instead,
this change makes reclamation cheaper, especially in terms of
synchronization overhead, and reactivation more expensive, because
reactivated pages will have to be reentered into the object's primary
splay tree and memq.
(2) Cached pages are now stored alongside free pages in the physical
memory allocator's buddy queues, increasing the likelihood that large
allocations of contiguous physical memory (i.e., superpages) will
succeed.
Finally, as a result of this change long-standing restrictions on when
and where a cached page can be reclaimed and returned by
vm_page_alloc(9) are eliminated. Specifically, calls to
vm_page_alloc(9) specifying VM_ALLOC_INTERRUPT can now reclaim and
return a formerly cached page. Consequently, a call to malloc(9)
specifying M_NOWAIT is less likely to fail.
Discussed with: many over the course of the summer, including jeff@,
Justin Husted @ Isilon, peter@, tegge@
Tested by: an earlier version by kris@
Approved by: re (kensmith)
In particular:
- smp_tlb_mtx is no longer used, so it is axed.
- smp rendezvous lock isn't really a leaf spin-mutex. Its bad placement in
the table, however, has been the source of a false positive LOR reporting
with the dt_lock. However, smp rendezvous lock would have had sched_lock
there for older lock, so it wasn't still a leaf lock.
- allpmaps is only used in ia32 architecture, so it is inserted in the
appropriate stub.
Addictionally:
- kse_zombie_lock is no longer present, so its definition is axed out.
- zombie_lock doesn't need to have an exported symbol, so just let's it be
declared as static.
Tested by: kris
Approved by: jeff (mentor)
Approved by: re
Together with the sys/i386/i386/trap.c rev. 1.306 it fixes the PR.
Submitted by: rdivacky
Suggested by: jhb
Sponsored by: Google Summer of Code 2007
PR: kern/77710
Approved by: re (kensmith)
3 arguments, but we had forgotten the second argument. Also make the
Linux statfs64 struct depend on the architecture because it has an
extra 4 bytes padding on amd64 compared to i386.
The three argument fix is from David Taylor, the struct statfs64
stuff is my fault. With this patch I can install i386 Linux matlab
on an amd64 machine.
Submitted by: David Taylor <davidt_at_yadt.co.uk>
Approved by: re (kensmith)
was used in assembler code in such a way that no unresolved relocation
records were generated, so ld didn't flag the problem. You can see
this with an 'nm' of the kernel. There will be 'U MAXCPU' on SMP systems.
The impact of this is that the intrcount/intrnames arrays do not have
the intended amount of space reserved. This could lead to interesting
problems due to the arrays being present in the middle of kernel code.
An overflow would be rather interesting as executable code would be used
as per-cpu incrementing interrupt counters.
This fixes it for now by exporting MAXCPU to the assembler. A better fix
might be to define these data structures in C - they're only referenced
in the kernel from C code these days anyway.
Approved by: re (kensmith)
- p_sflag was mostly protected by PROC_LOCK rather than the PROC_SLOCK or
previously the sched_lock. These bugs have existed for some time.
- Allow swapout to try each thread in a process individually and then
swapin the whole process if any of these fail. This allows us to move
most scheduler related swap flags into td_flags.
- Keep ki_sflag for backwards compat but change all in source tools to
use the new and more correct location of P_INMEM.
Reported by: pho
Reviewed by: attilio, kib
Approved by: re (kensmith)
of pages don't sum to anywhere near the total number of pages on amd64.
This is for the most part because uma_small_alloc() pages have never been
counted as wired pages, like their kmem_malloc() brethren. They should
be. This changes fixes that.
It is no longer necessary for the page queues lock to be held to free
pages allocated by uma_small_alloc(). I removed the acquisition and
release of the page queues lock from uma_small_free() on amd64 and ia64
weeks ago. This patch updates the other architectures that have
uma_small_alloc() and uma_small_free().
Approved by: re (kensmith)
per-primitive macros like MTX_NOPROFILE, SX_NOPROFILE or RW_NOPROFILE) is
not really honoured. In particular lock_profile_obtain_lock_failure() and
lock_profile_obtain_lock_success() are naked respect this flag.
The bug leads to locks marked with no-profiling to be profiled as well.
In the case of the clock_lock, used by the timer i8254 this leads to
unpredictable behaviour both on amd64 and ia32 (double faults panic,
sudden reboots, etc.). The amd64 clock_lock is also not marked as
not profilable as it should be.
Fix these bugs adding proper checks in the lock profiling code and at
clock_lock initialization time.
i8254 bug pointed out by: kris
Tested by: matteo, Giuseppe Cocomazzi <sbudella at libero dot it>
Approved by: jeff (mentor)
Approved by: re
topology foo functions.
Working at the patch for topology problems in ia32/amd64 evicted some
problems regarding functions ordering in the SI_SUB_CPU family of
SYSINIT'ed subsystems.
In order to avoid problems with new modified to involved functions, a
correct ordering is not semantically specified for SI_SUB_CPU functions
(for a larger view of the issue please visit:
http://lists.freebsd.org/pipermail/freebsd-current/2007-July/075409.html )
Discussed with: peter
Tested by: kris, Rui Paulo <rpaulo@FreeBSD.org>
Approved by: jeff
Approved by: re
with Linux 2.6 emulation. This shall be reimplemented once FreeBSD gets
native scheduler affinity syscalls.
Submitted by: rdivacky
Reviewed by: jkim
Sponsored by: Google Summer of Code 2007
Approved by: re (kensmith)
longer create a pv entry for that mapping. (The two exceptions are
mappings into the kernel's exec and pipe submaps.) Consequently, there is
no reason for get_pv_entry() to dig deep into the free page queues, i.e.,
use VM_ALLOC_SYSTEM, by default. This revision changes get_pv_entry() to
use VM_ALLOC_NORMAL by default, i.e., before calling pmap_collect() to
reclaim pv entries.
Approved by: re (kensmith)
and newer CPUs (including Core 2 and Core / Core 2 based Xeons). The
driver attaches to each cpu device and creates a sysctl node in that
device's sysctl context (dev.cpu.N.temperature). When invoked, the
handler binds to the appropriate CPU to ensure a correct reading.
Submitted by: Rui Paulo <rpaulo@fnop.net>
Sponsored by: Google Summer of Code 2007
Tested by: des, marcus, Constantine A. Murenin, Ian FREISLICH
Approved by: re (kensmith)
MFC after: 3 weeks
cpu_start_mp(). This is after we have read the cpuid registers to
calculate the hyperthreading_cpus value for the sysctl that enables or
disables hyperthread cores. Change mp_topology() to use that information
rather than trying to do it itself.
This solves the problem of ULE being incorrectly told that dual core
Athlon64 X2 or Operton cpus are hyperthreading cores. At the very least,
we now have a single piece of code to identify hyperthreading.
Obtained from: jhb
Approved by: re (kensmith)
value, then we would use a negative index into the trap_msg[] array
resulting in a nested page fault. Make the 'type' variable holding the
trap number unsigned to avoid this.
MFC after: 2 weeks
Approved by: re (rwatson)
print a one line error message. Add some comments on not being able to
trust the day of week field (I'll act on these comments in a follow up
commit).
Approved by: re
MFC after: 3 weeks
require fewer blocking loops.
- Don't use atomic ops with 4BSD or on UP.
- Only use the blocking loop if ULE is compiled in.
- Use the correct memory barrier.
Discussed with: attilio, jhb, ssouhlal
Tested by: current@
Approved by: re
kernels exposed by the recent fixes to resource limits for 32-bit processes
on 64-bit kernels:
- Let ABIs expose their maximum stack size via a new pointer in sysentvec
and use that in preference to maxssiz during exec() rather than always
using maxssiz for all processses.
- Apply the ABI's limit fixup to the previous stack size when adjusting
RLIMIT_STACK to determine if the existing mapping for the stack needs to
be grown or shrunk (as well as how much it should be grown or shrunk).
Approved by: re (kensmith)
