in scheduler-intense workloads native_read_tsc() overhead accounts for
20% of the system overhead:

 659567 system_call                              41222.9375
 686796 schedule                                 435.7843
 718382 __switch_to                              665.1685
 823875 switch_mm                                4526.7857
 1883122 native_read_tsc                          55385.9412
 9761990 total                                      2.8468

this is large part due to the rdtsc_barrier() that is done before
and after reading the TSC.

But sched_clock() is not a precise clock in the GTOD sense, using such
barriers is completely pointless. So remove the barriers and only use
them in vget_cycles().

This improves lat_ctx performance by about 5%.
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: fix warning message when PARAVIRT is set in config

Remove stale #ifdef components from our IRQ sizing logic.
x86/Voyager is the only holdout.
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: make NR_IRQS big enough for system with lots of apic/pins

If lots of IO_APIC's are there (or can be there), size the same way
as 64-bit, depending on MAX_IO_APICS and NR_CPUS.

This fixes the boot problem reported by Ben Hutchings on a 32-bit
server with 5 IO-APICs and 240 IO-APIC pins.
Signed-off-by: NYinghai <yinghai@kernel.org>
Tested-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: improve wakeup affinity on NUMA systems, tweak SMP systems

Given the fixes+tweaks to the wakeup-buddy code, re-tweak the domain
balancing defaults on NUMA and SMP systems.

Turn on SD_WAKE_AFFINE which was off on x86 NUMA - there's no reason
why we would not want to have wakeup affinity across nodes as well.
(we already do this in the standard NUMA template.)

lat_ctx on a NUMA box is particularly happy about this change:

before:

 |   phoenix:~/l> ./lat_ctx -s 0 2
 |   "size=0k ovr=2.60
 |   2 5.70

after:

 |   phoenix:~/l> ./lat_ctx -s 0 2
 |   "size=0k ovr=2.65
 |   2 2.07

a 2.75x speedup.

pipe-test is similarly happy about it too:

 |  phoenix:~/sched-tests> ./pipe-test
 |   18.26 usecs/loop.
 |   14.70 usecs/loop.
 |   14.38 usecs/loop.
 |   10.55 usecs/loop.              # +WAKE_AFFINE on domain0+domain1
 |   8.63 usecs/loop.
 |   8.59 usecs/loop.
 |   9.03 usecs/loop.
 |   8.94 usecs/loop.
 |   8.96 usecs/loop.
 |   8.63 usecs/loop.

Also:

 - disable SD_BALANCE_NEWIDLE on NUMA and SMP domains (keep it for siblings)
 - enable SD_WAKE_BALANCE on SMP domains

Sysbench+postgresql improves all around the board, quite significantly:

           .28-rc3-11474e2c  .28-rc3-11474e2c-tune
-------------------------------------------------
    1:             571              688    +17.08%
    2:            1236             1206    -2.55%
    4:            2381             2642    +9.89%
    8:            4958             5164    +3.99%
   16:            9580             9574    -0.07%
   32:            7128             8118    +12.20%
   64:            7342             8266    +11.18%
  128:            7342             8064    +8.95%
  256:            7519             7884    +4.62%
  512:            7350             7731    +4.93%
-------------------------------------------------
  SUM:           55412            59341    +6.62%

So it's a win both for the runup portion, the peak area and the tail.
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: fix x86/Voyager build

Looks like this became static on the rest of x86.  Fix it up by adding
an external definition to mach-voyager/setup.c
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: fix xsave slowdown regression

Fix two features from conflicting in feature bits.

Fixes this performance regression:

   Subject: cpu2000(both float and int) 13% regression with 2.6.28-rc1
   http://lkml.org/lkml/2008/10/28/36Reported-by: N"Zhang, Yanmin" <yanmin_zhang@linux.intel.com>
Bisected-by: N"Zhang, Yanmin" <yanmin_zhang@linux.intel.com>
Signed-off-by: NVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: introduce new APIs, separate kmap code from CONFIG_HIGHMEM

This takes the code used for CONFIG_HIGHMEM memory mappings except that
it's designed for dynamic IO resource mapping.

These fixmaps are available even with CONFIG_HIGHMEM turned off.
Signed-off-by: NKeith Packard <keithp@keithp.com>
Signed-off-by: NEric Anholt <eric@anholt.net>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: change the kexec bootstrap code implementation from assembly to C

This patch transforms the kexec page tables setup code from assembler
code to C code in machine_kexec_prepare. This improves readability and
reduces code line number.
Signed-off-by: NHuang Ying <ying.huang@intel.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: save .text size when kexec is built in but not loaded

This patch adds an architecture specific struct kimage_arch into
struct kimage. The pointers to page table pages used by kexec are
added to struct kimage_arch. The page tables pages are dynamically
allocated in machine_kexec_prepare instead of statically from BSS
segment. This will save up to 20k memory when kexec image is not
loaded.
Signed-off-by: NHuang Ying <ying.huang@intel.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: build fix on x86/Voyager

Given commits like this:

| Author: Suresh Siddha <suresh.b.siddha@intel.com>
| Date:   Tue Jul 29 10:29:19 2008 -0700
|
|     x86, xsave: enable xsave/xrstor on cpus with xsave support

Which deliberately expose boot cpu dependence to pieces of the system,
I think it's time to explicitly have a variable for it to prevent this
continual misassumption that the boot CPU is zero.
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: include file dependency cleanup

Fix compile errors of files that include asm/uv/uv_hub.h but do
not include linux/timer.h.

[ such files are not mainline right now. ]
Signed-of-by: NMike Travis <travis@sgi.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: cleanup

To the unsuspecting user it is quite annoying that this broken and
inconsistent with x86-64 definition still exists.
Signed-off-by: NJan Beulich <jbeulich@novell.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: some new sparse warnings in e820.c etc, but no functional change.

As with regular ioremap, iounmap etc, annotate with __iomem.

Fixes the following sparse warnings, will produce some new ones
elsewhere in arch/x86 that will get worked out over time.

arch/x86/mm/ioremap.c:402:9: warning: cast removes address space of expression
arch/x86/mm/ioremap.c:406:10: warning: cast adds address space to expression (<asn:2>)
arch/x86/mm/ioremap.c:782:19: warning: Using plain integer as NULL pointer
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

APIC_DEBUG is always 2.
need to update inquire_remote_apic to check apic_verbosity with
it instead.
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Every call of kvm_set_irq() should offer an irq_source_id, which is
allocated by kvm_request_irq_source_id(). Based on irq_source_id, we
identify the irq source and implement logical OR for shared level
interrupts.

The allocated irq_source_id can be freed by kvm_free_irq_source_id().

Currently, we support at most sizeof(unsigned long) different irq sources.

[Amit: - rebase to kvm.git HEAD
       - move definition of KVM_USERSPACE_IRQ_SOURCE_ID to common file
       - move kvm_request_irq_source_id to the update_irq ioctl]

[Xiantao: - Add kvm/ia64 stuff and make it work for kvm/ia64 guests]
Signed-off-by: NSheng Yang <sheng@linux.intel.com>
Signed-off-by: NAmit Shah <amit.shah@redhat.com>
Signed-off-by: NXiantao Zhang <xiantao.zhang@intel.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

On Thu, Oct 23, 2008 at 04:09:52PM -0700, Alexander Beregalov wrote:
> arch/x86/kernel/built-in.o: In function `iommu_setup':
> pci-dma.c:(.init.text+0x36ad): undefined reference to `forbid_dac'
> pci-dma.c:(.init.text+0x36cc): undefined reference to `forbid_dac'
> pci-dma.c:(.init.text+0x3711): undefined reference to `forbid_dac

This patch partially reverts a patch to add IOMMU support to ia64.  The
forbid_dac variable was incorrectly moved to quirks.c, which isn't built
when PCI is disabled.
Tested-by: N"Alexander Beregalov" <a.beregalov@gmail.com>
Acked-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: NFenghua Yu <fenghua.yu@intel.com>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>

dma_alloc_coherent (include/asm-x86/dma-mapping.h) avoids GFP_DMA
allocation first and if the allocated address is not fit for the
device's coherent_dma_mask, then dma_alloc_coherent does GFP_DMA
allocation. This is because dma_alloc_coherent avoids precious GFP_DMA
zone if possible. This is also how the old dma_alloc_coherent
(arch/x86/kernel/pci-dma.c) works.

However, if the coherent_dma_mask of a device is 24bit, there is no
point to go into the above GFP_DMA retry mechanism. We had better use
GFP_DMA in the first place.
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Tested-by: NTakashi Iwai <tiwai@suse.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Canonicalize a few remaining header guards, with the exception for
those which are still in subarchitecture directories.
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Drop double underscores from header guards in arch/x86/include.  They
are used inconsistently, and are not necessary.
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Change header guards named "ASM_X86__*" to "_ASM_X86_*" since:

a. the double underscore is ugly and pointless.
b. no leading underscore violates namespace constraints.
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>