Currently the i386 HPET code assumes the entire HPET implementation from
the spec is present.  This breaks on boxes that do not implement the
optional legacy timer replacement functionality portion of the spec.

This patch, which is very similar to my x86-64 patch for the same issue,
fixes the problem allowing i386 systems that cannot use the HPET for the
timer interrupt and RTC to still use the HPET as a time source.  I've
tested this patch on a system systems without HPET, with HPET but without
legacy timer replacement, as well as HPET with legacy timer replacement.
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The recent support for K8 multicore was misported from x86-64 to i386, due
to an unnecessary inconsistency between the CPUID code.  Sure, there is are
no x86-64 VIA chips yet, but it should happen eventually.

This patch fixes the i386 bug as well as makes x86-64 match i386 in the
handing of the CPUID array.
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Enable write combining for server works LE rev > 6 per
http://www.ussg.iu.edu/hypermail/linux/kernel/0104.3/1007.htmlSigned-Off-By: NLee Revell <rlrevell@joe-job.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

do_debug() and do_int3() return void.

This patch fixes the CONFIG_KPROBES variant of do_int3() to return void too
and adjusts entry.S accordingly.
Signed-off-by: NStas Sergeev <stsp@aknet.ru>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch by Jaya Kumar introduces a generic infrastructure to deal with
x86 chipsets with nonstandard reset sequences, and adds support for the
Geode gx1/cs5530a chipset.
Signed-off-by: NJaya Kumar <jayalk@intworks.biz>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

A bug against an xSeries system showed up recently noting that the
check_nmi_watchdog() test was failing.

I have been investigating it and discovered in both i386 and x86_64 the
recent change to the routine to use the cpu_callin_map has uncovered a
problem.  Prior to that change, on an SMP box, the test was trivally
passing because all cpu's were found to not yet be online, but now with the
callin_map they are discovered, it goes on to test the counter and they
have not yet begun to increment, so it announces a CPU is stuck and bails
out.

On all the systems I have access to test, the announcement of failure is
also bougs...  by the time you can login and check /proc/interrupts, the
NMI count is happily incrementing on all CPUs.  Its just that the test is
being done too early.

I have tried moving the call to the test around a bit, and it was always
too early.  I finally hit on this proposed solution, it delays the routine
via a late_initcall(), seems like the right solution to me.
Signed-off-by: NAdrian Bunk <bunk@stusta.de>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The new i386/x86_64 assemblers no longer accept instructions for moving
between a segment register and a 32bit memory location, i.e.,

        movl (%eax),%ds
        movl %ds,(%eax)

To generate instructions for moving between a segment register and a
16bit memory location without the 16bit operand size prefix, 0x66,

        mov (%eax),%ds
        mov %ds,(%eax)

should be used. It will work with both new and old assemblers. The
assembler starting from 2.16.90.0.1 will also support

        movw (%eax),%ds
        movw %ds,(%eax)

without the 0x66 prefix. I am enclosing patches for 2.4 and 2.6 kernels
here. The resulting kernel binaries should be unchanged as before, with
old and new assemblers, if gcc never generates memory access for

               unsigned gsindex;
               asm volatile("movl %%gs,%0" : "=g" (gsindex));

If gcc does generate memory access for the code above, the upper bits
in gsindex are undefined and the new assembler doesn't allow it.
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch shortens non-constant memcpy() by two bytes and fixes spurious
out-of-line constant memcpy().

# size vmlinux.org vmlinux
   text    data     bss     dec     hex filename
3954591 1553426  236544 5744561  57a7b1 vmlinux.org
3952615 1553426  236544 5742585  579ff9 vmlinux
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

On our raw spinlocks, we currently have an attempt at the lock, and if we do
not get it we enter a spin loop.  This spinloop will likely continue for
awhile, and we pridict likely.

Shouldn't we predict that we will get out of the loop so our next instructions
are already prefetched.  Even when we miss because the lock is still held, it
won't matter since we are waiting anyways.

I did a couple quick benchmarks, but the results are inconclusive.

	16-way 690 running specjbb with original code
	# ./specjbb 3000 16 1 1 19 30 120
	    ...
	Valid run, Score is 59282

	16-way 690 running specjbb with unlikely code
	# ./specjbb 3000 16 1 1 19 30 120
	    ...
	Valid run, Score is 59541

I saw a smaller increase on a JS20 (~1.6%)

	JS20 specjbb w/ original code
	# ./specjbb 400 2 1 1 19 30 120
	   ...
	Valid run, Score is 20460

	JS20 specjbb w/ unlikely code
	# ./specjbb 400 2 1 1 19 30 120
	   ...
	Valid run, Score is 20803

Anton said:

Mispredicting the spinlock busy loop also means we slow down the rate at which
we do the loads which can be good for heavily contended locks.

Note: There are some gcc issues with our default build and branch prediction,
but a CONFIG_POWER4_ONLY build should emit them correctly.  I'm working with
Alan Modra on it now.
Signed-off-by: NJake Moilanen <moilanen@austin.ibm.com>
Signed-off-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Replace a number of memory barriers with smp_ variants.  This means we won't
take the unnecessary hit on UP machines.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Use smp_mb and smp_wmb. In particular smp_wmb is lighter weight than wmb.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Calls into the hypervisor do not raise the thread priority.  Ensure we are
running at medium priority upon entry to the hypervisor.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Recent gcc 4.0 testing uncovered a firmware issue.  Some properties are larger
than 31 bytes and due to gcc 4.0s better stack allocation this overflow ran
over non volatile register storage.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

We no longer use any ppcdebug stuff in a.out.h, so remove the define.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

There were a few issues with the ppc64 noexec support:

The 64bit ABI has a non executable stack by default.  At the moment 64bit apps
require a PT_GNU_STACK section in order to have a non executable stack.

Disable the read implies exec workaround on the 64bit ABI.  The 64bit
toolchain has never had problems with incorrect mmap permissions (the 32bit
has, thats why we need to retain the workaround).

With these fixes as well as a gcc fix from Alan Modra (that was recently
committed) 64bit apps work as expected.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

It turns out that our current __hash_page code will do a very hot busy-wait
loop waiting on _PAGE_BUSY to be cleared.  It even does ldarx/stdcx in the
loop, which will bounce reservations around like crazy if there's more than
one CPU spinning on the same PTE (or even another PTE in the same
reservation granule).  The end result is that each fault takes longer when
there's contention, which in turn increases the chance of another thread
hitting the same fault and also piling up.  Not pretty.

There's two options here:
1. Do an out-of-line busy loop a'la spinlocks with just loads (no
   reserves)
2. Just bail and refault if needed.

(2) makes sense here: If the PTE is busy, chances are it's in flux anyway
and the other code path making a change might just be ready to hash it.

This fixes a stampede seen on a large-ish system where a multithreaded
HPC app faults in the same text pages on several cpus at the same time.
Signed-off-by: NOlof Johansson <olof@lixom.net>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

On pSeries systems, according to the platform architecture specs, we are
supposed to be supplying a structure to firmware that tells firmware about
our capabilities, such as which version of the data structures that
describe available memory we are expecting to see.  The way we end up
having to supply this data structure is a bit gross, since it was designed
for AIX and doesn't suit us very well.  This patch adds the code to supply
this data structure to the firmware.
Signed-off-by: NPaul Mackerras <paulus@samba.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch converts ppc64 to use the generic pgtable-nopud.h instead of the
"fixup" header.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

- Fix

  arch/ppc64/kernel/nvram.c:342: warning: `part' might be used uninitialized in this function

- Various codingstyle tweaks.
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

When I tried Ben's patches to the powermac sound driver on my G5, I found
that it was taking enormous numbers of sound DMA transmit interrupts.  This
turned out to be because it was incorrectly configured as level-sensitive
instead of edge-sensitive, which in turn was because the code that parses
the interrupt tree that Open Firmware gives us was incorrectly assigning
another device the same irq number as the sound DMA transmit interrupt
(i.e.  1).

This patch fixes the problem, in a somewhat quick and dirty way for now,
but one which will work for all the machines we currently run on.
Ultimately Ben and I want to do something more general and robust, but this
should go in for 2.6.12.
Signed-off-by: NPaul Mackerras <paulus@samba.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Remove vsid argument to create_slbe, since it's no longer used.

Spotted by R Sharada.
Signed-off-by: NOlof Johansson <olof@austin.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch from Roland adds a PT_NOTE section to both 32 and 64 bits vDSOs
to expose the kernel version to glibc, thus avoiding a uname syscall on
every launch.  This is equivalent to the patches Roland posted already for
x86 and x86-64.

Note: the 64 bits .note is actually using the 32 bits format.  This is
normal.  The ELF spec specifies a different format for 64 bits .note, but
for some reason, this was never properly implemented, the core dumps for
example are all using 32 bits format .note, and binutils cannot even read a
64 bits format .note.  Talking to our toolchain folks, they think we'd
rather stick to 32 bits format .note everywhere and get the spec fixed some
day ...
Signed-off-by: NRoland McGrath <roland@redhat.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Ben's patch that shutdowns master switch and restores it after resume
("pmac: Improve sleep code of tumbler driver") isn't enough here on an
iBook (snapper chip).

The master switch is correctly saved and restored, but somehow
tumbler_put_master_volume() gets called just after
tumbler_set_master_volume() and sets mix->master_vol[*] to 0.  So, on
resuming, the master switch is reenabled, but the volume is set to 0.

Here's a patch that also saves and restores master_vol.
Signed-off-by: NColin Leroy <colin@colino.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch applies on top of my previous g5 related sound patches and adds
support for the Mac Mini to the PowerMac Alsa driver.

However, I haven't found any kind of HW support for volume control on this
machine.  If it exist, it's well hidden.  That means that you probably want
to make sure you use software with the ability to do soft volume control,
or use Alsa 0.9 pre-release with the softvol plugin.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch fixes a couple more issues with the management of the GPIOs
dealing with headphone and line out mute on the G5.  It should fix the
remaining problems of people not getting any sound out of the headphone
jack.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

There is a problem with large amounts of spurious IRQs on PowerPC 82xx
systems.

The problem is corrected by adding sync at the end of cpm2_mask_and_ack.
This may be needed on 8xx as well but has not yet been confirmed.
Signed-off-by: NEugene Surovegin <ebs@ebshome.net>
Signed-off-by: NDan Malek <dan@embeddedalley.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The handling of misaligned load/store multiple instructions did not check
to see if the address was ok to access before using __{get,put}_user().
Signed-off-by: NKumar Gala <kumar.gala@freescale.com>
Signed-off-by: NPaul Mackerras <paulus@samba.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Some earlier models of aluminium powerbooks and ibook G4s have a clock chip
that requires some tweaking before and after sleep.  It seems that without
that magic incantation to disable and re-enable clock spreading, RAM isn't
properly refreshed during sleep.  This fixes it.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch adds support for the special adb buttons of the aluminium
PowerBook G4.
Signed-off-by: NAndreas Jaggi <andreas.jaggi@waterwave.ch>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

I noticed an occasional crash on wakeup from sleep on my powerbook
(strangly never happened before, probably timing related) that appears to
be due to a dangling interrupt while the chip is put to sleep and beeing
reset on wakeup.

This patch fixes is by disabling the irq in the ide pmac driver while
asleep and only re-enable it after the chip has been fully reset.  This is
safe to do so as the interrupt of these apple IDE cells is never shared.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch adds the hooks into the PPC7D platforms file to support the DS1337
RTC device as the clock device for the PPC7D board.
Signed-off-by: NChris Elston <chris.elston@radstone.co.uk>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch fixes the SDRAM output from /proc/cpuinfo.  The previous code
assumed that there was only one bank of SDRAM, and that the size in the memory
configuration register was the total size.
Signed-off-by: NChris Elston <chris.elston@radstone.co.uk>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Moved common FPU exception handling code out of head.S so it can be used by
several of the sub-architectures that might of a full PowerPC FPU.

Also, uses new CONFIG_PPC_FPU define to fix alignment exception handling
for floating point load/store instructions to only occur if we have a
hardware FPU.
Signed-off-by: NJason McMullan <jason.mcmullan@timesys.com>
Signed-off-by: NKumar Gala <kumar.gala@freescale.com>
Signed-off-by: NPaul Mackerras <paulus@samba.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Some G3 CPUs can crash in funny way if a store from an FPU register
instruction is executed on a register that has never been initialized since
power on.  This patch fixes it by making sure all FP registers have been
properly initialized at kernel boot and when waking from sleep.  It also makes
the code that decides wether HID0_BTIC and HID0_DPM are allowed on a given CPU
smarter (it can actually _clear_ them now if they are not allowed instead of
just setting them when they are allowed in case the firmware got them wrong)
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch provides finer grained permissions for the audit family of
Netlink sockets under SELinux.

1.  We need a way to differentiate between privileged and unprivileged
   reads of kernel data maintained by the audit subsystem.  The AUDIT_GET
   operation is unprivileged: it returns the current status of the audit
   subsystem (e.g.  whether it's enabled etc.).  The AUDIT_LIST operation
   however returns a list of the current audit ruleset, which is considered
   privileged by the audit folk.  To deal with this, a new SELinux
   permission has been implemented and applied to the operation:
   nlmsg_readpriv, which can be allocated to appropriately privileged
   domains.  Unprivileged domains would only be allocated nlmsg_read.

2.  There is a requirement for certain domains to generate audit events
   from userspace.  These events need to be collected by the kernel,
   collated and transmitted sequentially back to the audit daemon.  An
   example is user level login, an auditable event under CAPP, where
   login-related domains generate AUDIT_USER messages via PAM which are
   relayed back to auditd via the kernel.  To prevent handing out
   nlmsg_write permissions to such domains, a new permission has been
   added, nlmsg_relay, which is intended for this type of purpose: data is
   passed via the kernel back to userspace but no privileged information is
   written to the kernel.

Also, AUDIT_LOGIN messages are now valid only for kernel->user messaging,
so this value has been removed from the SELinux nlmsgtab (which is only
used to check user->kernel messages).
Signed-off-by: NJames Morris <jmorris@redhat.com>
Signed-off-by: NStephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch removes the sclass argument from ipc_has_perm in the SELinux
module, as it can be obtained from the ipc security structure.  The use of
a separate argument was a legacy of the older precondition function
handling in SELinux and is obsolete.  Please apply.
Signed-off-by: NStephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: NJames Morris <jmorris@redhat.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

In rare situations, drop_buffers() can be called for a page which has buffers,
but no ->mapping (it was truncated, but the buffers were left behind because
ext3 was still fiddling with them).

But if there was an I/O error in a buffer_head, drop_buffers() will try to get
at the address_space and will oops.
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

When ->writepage() returns WRITEPAGE_ACTIVATE, the page is still locked.
Explicitly unlock the page in mpage_writepages().
Signed-off-by: NNikita Danilov <nikita@clusterfs.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The patch makes the following function calls available to allocate memory
on a specific node without changing the basic operation of the slab
allocator:

 kmem_cache_alloc_node(kmem_cache_t *cachep, unsigned int flags, int node);
 kmalloc_node(size_t size, unsigned int flags, int node);

in a similar way to the existing node-blind functions:

 kmem_cache_alloc(kmem_cache_t *cachep, unsigned int flags);
 kmalloc(size, flags);

kmem_cache_alloc_node was changed to pass flags and the node information
through the existing layers of the slab allocator (which lead to some minor
rearrangements).  The functions at the lowest layer (kmem_getpages,
cache_grow) are already node aware.  Also __alloc_percpu can call
kmalloc_node now.

Performance measurements (using the pageset localization patch) yields:

w/o patches:
Tasks    jobs/min  jti  jobs/min/task      real       cpu
    1      484.27  100       484.2736     12.02      1.97   Wed Mar 30 20:50:43 2005
  100    25170.83   91       251.7083     23.12    150.10   Wed Mar 30 20:51:06 2005
  200    34601.66   84       173.0083     33.64    294.14   Wed Mar 30 20:51:40 2005
  300    37154.47   86       123.8482     46.99    436.56   Wed Mar 30 20:52:28 2005
  400    39839.82   80        99.5995     58.43    580.46   Wed Mar 30 20:53:27 2005
  500    40036.32   79        80.0726     72.68    728.60   Wed Mar 30 20:54:40 2005
  600    44074.21   79        73.4570     79.23    872.10   Wed Mar 30 20:55:59 2005
  700    44016.60   78        62.8809     92.56   1015.84   Wed Mar 30 20:57:32 2005
  800    40411.05   80        50.5138    115.22   1161.13   Wed Mar 30 20:59:28 2005
  900    42298.56   79        46.9984    123.83   1303.42   Wed Mar 30 21:01:33 2005
 1000    40955.05   80        40.9551    142.11   1441.92   Wed Mar 30 21:03:55 2005

with pageset localization and slab API patches:
Tasks    jobs/min  jti  jobs/min/task      real       cpu
    1      484.19  100       484.1930     12.02      1.98   Wed Mar 30 21:10:18 2005
  100    27428.25   92       274.2825     21.22    149.79   Wed Mar 30 21:10:40 2005
  200    37228.94   86       186.1447     31.27    293.49   Wed Mar 30 21:11:12 2005
  300    41725.42   85       139.0847     41.84    434.10   Wed Mar 30 21:11:54 2005
  400    43032.22   82       107.5805     54.10    582.06   Wed Mar 30 21:12:48 2005
  500    42211.23   83        84.4225     68.94    722.61   Wed Mar 30 21:13:58 2005
  600    40084.49   82        66.8075     87.12    873.11   Wed Mar 30 21:15:25 2005
  700    44169.30   79        63.0990     92.24   1008.77   Wed Mar 30 21:16:58 2005
  800    43097.94   79        53.8724    108.03   1155.88   Wed Mar 30 21:18:47 2005
  900    41846.75   79        46.4964    125.17   1303.38   Wed Mar 30 21:20:52 2005
 1000    40247.85   79        40.2478    144.60   1442.21   Wed Mar 30 21:23:17 2005
Signed-off-by: NChristoph Lameter <christoph@lameter.com>
Signed-off-by: NManfred Spraul <manfred@colorfullife.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The smp_mb() is becaus sync_page() doesn't have PG_locked while it accesses
page_mapping(page).  The comments in the patch (the entire patch is the
addition of this comment) try to explain further how and why smp_mb() is
used.
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>