Commit graph

6683 commits

Author SHA1 Message Date
Yinghai Lu
129d8bc828 x86: don't compile vsmp_64 for 32bit
Impact: cleanup

that is only needed when CONFIG_X86_VSMP is defined with 64bit
also remove dead code about PCI, because CONFIG_X86_VSMP depends on PCI

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Ravikiran Thirumalai <kiran@scalex86.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-26 06:40:06 +01:00
Yinghai Lu
2b6163bf57 x86: remove update_apic from x86_quirks
Impact: cleanup

x86_quirks->update_apic() calling looks crazy. so try to remove it:

 1. every apic take wakeup_cpu member directly
 2. separate es7000_apic to es7000_apic_cluster
 3. use uv_wakeup_cpu directly

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-26 06:32:25 +01:00
Ingo Molnar
ecc25fbd6b Merge branches 'x86/apic', 'x86/defconfig', 'x86/memtest', 'x86/mm' and 'linus' into x86/core 2009-02-26 06:31:32 +01:00
Ingo Molnar
801c0be814 Merge branches 'x86/urgent' and 'x86/pat' into x86/core
Conflicts:
	arch/x86/include/asm/pat.h
2009-02-26 06:31:23 +01:00
Ingo Molnar
13b2eda64d Merge branch 'x86/urgent' into x86/core
Conflicts:
	arch/x86/mach-voyager/voyager_smp.c
2009-02-26 06:30:42 +01:00
Ingo Molnar
13093cb0e5 gpu/drm, x86, PAT: PAT support for io_mapping_*, export symbols for modules
Impact: build fix

 ERROR: "reserve_io_memtype_wc" [drivers/gpu/drm/i915/i915.ko] undefined!
 ERROR: "free_io_memtype" [drivers/gpu/drm/i915/i915.ko] undefined!

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-26 03:43:53 +01:00
Jeremy Fitzhardinge
55d8085671 xen: disable interrupts early, as start_kernel expects
This avoids a lockdep warning from:
	if (DEBUG_LOCKS_WARN_ON(unlikely(!early_boot_irqs_enabled)))
		return;
in trace_hardirqs_on_caller();

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Cc: Xen-devel <xen-devel@lists.xensource.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 18:51:57 +01:00
Ingo Molnar
2e31add2a7 Merge branch 'x86/urgent' into x86/pat 2009-02-25 16:40:10 +01:00
Peter Zijlstra
34754b69a6 x86: make vmap yell louder when it is used under irqs_disabled()
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 16:38:34 +01:00
Venkatesh Pallipadi
17581ad812 gpu/drm, x86, PAT: PAT support for io_mapping_*
Make io_mapping_create_wc and io_mapping_free go through PAT to make sure
that there are no memory type aliases.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Eric Anholt <eric@anholt.net>
Cc: Keith Packard <keithp@keithp.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 13:09:52 +01:00
Venkatesh Pallipadi
4ab0d47d0a gpu/drm, x86, PAT: io_mapping_create_wc and resource_size_t
io_mapping_create_wc should take a resource_size_t parameter in place of
unsigned long. With unsigned long, there will be no way to map greater than 4GB
address in i386/32 bit.

On x86, greater than 4GB addresses cannot be mapped on i386 without PAE. Return
error for such a case.

Patch also adds a structure for io_mapping, that saves the base, size and
type on HAVE_ATOMIC_IOMAP archs, that can be used to verify the offset on
io_mapping_map calls.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Eric Anholt <eric@anholt.net>
Cc: Keith Packard <keithp@keithp.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 13:09:51 +01:00
Venkatesh Pallipadi
7880f74645 gpu/drm, x86, PAT: routine to keep identity map in sync
Add a function to check and keep identity maps in sync, when changing
any memory type. One of the follow on patches will also use this
routine.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Eric Anholt <eric@anholt.net>
Cc: Keith Packard <keithp@keithp.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 13:09:51 +01:00
Andreas Herrmann
63823126c2 x86: memtest: add additional (regular) test patterns
Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 12:19:47 +01:00
Andreas Herrmann
bfb4dc0da4 x86: memtest: wipe out test pattern from memory
Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 12:19:46 +01:00
Andreas Herrmann
570c9e69aa x86: memtest: adapt log messages
- print test pattern instead of pattern number,
- show pattern as stored in memory,
- use proper priority flags,
- consistent use of u64 throughout the code

Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 12:19:46 +01:00
Andreas Herrmann
7dad169e57 x86: memtest: cleanup memtest function
Impact: code cleanup

Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 12:19:45 +01:00
Andreas Herrmann
6d74171bf7 x86: memtest: introduce array to select memtest patterns
Impact: code cleanup

Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 12:19:45 +01:00
Andreas Herrmann
40823f737e x86: memtest: reuse test patterns when memtest parameter exceeds number of available patterns
Impact: fix unexpected behaviour when pattern number is out of range

Current implementation provides 4 patterns for memtest. The code doesn't
check whether the memtest parameter value exceeds the maximum pattern number.

Instead the memtest code pretends to test with non-existing patterns, e.g.
when booting with memtest=10 I've observed the following

  ...
  early_memtest: pattern num 10
  0000001000 - 0000006000 pattern 0
  ...
  0000001000 - 0000006000 pattern 1
  ...
  0000001000 - 0000006000 pattern 2
  ...
  0000001000 - 0000006000 pattern 3
  ...
  0000001000 - 0000006000 pattern 4
  ...
  0000001000 - 0000006000 pattern 5
  ...
  0000001000 - 0000006000 pattern 6
  ...
  0000001000 - 0000006000 pattern 7
  ...
  0000001000 - 0000006000 pattern 8
  ...
  0000001000 - 0000006000 pattern 9
  ...

But in fact Linux didn't test anything for patterns > 4 as the default
case in memtest() is to leave the function.

I suggest to use the memtest parameter as the number of tests to be
performed and to re-iterate over all existing patterns.

Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 12:19:44 +01:00
Ingo Molnar
95108fa34a x86: usercopy: check for total size when deciding non-temporal cutoff
Impact: make more types of copies non-temporal

This change makes the following simple fix:

  30d697f: x86: fix performance regression in write() syscall

A bit more sophisticated: we check the 'total' number of bytes
written to decide whether to copy in a cached or a non-temporal
way.

This will for example cause the tail (modulo 4096 bytes) chunk
of a large write() to be non-temporal too - not just the page-sized
chunks.

Cc: Salman Qazi <sqazi@google.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 10:20:05 +01:00
Ingo Molnar
3255aa2eb6 x86, mm: pass in 'total' to __copy_from_user_*nocache()
Impact: cleanup, enable future change

Add a 'total bytes copied' parameter to __copy_from_user_*nocache(),
and update all the callsites.

The parameter is not used yet - architecture code can use it to
more intelligently decide whether the copy should be cached or
non-temporal.

Cc: Salman Qazi <sqazi@google.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 10:20:03 +01:00
Ingo Molnar
95f66b3770 Merge branch 'x86/asm' into x86/mm 2009-02-25 08:27:46 +01:00
Tejun Heo
d325100504 x86: convert cacheflush macros inline functions
Impact: cleanup

Unused macro parameters cause spurious unused variable warnings.
Convert all cacheflush macros to inline functions to avoid the
warnings and achieve better type checking.

Signed-off-by: Tejun Heo <tj@kernel.org>
2009-02-25 11:06:51 +09:00
Tejun Heo
24ff954233 x86, percpu: fix minor bugs in setup_percpu.c
Recent changes in setup_percpu.c made a now meaningless DBG()
statement fail to compile and introduced a
comparison-of-different-types warning.  Fix them.

Compile failure is reported by Ingo Molnar.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 10:38:10 +09:00
H. Peter Anvin
638bee71c8 Merge branch 'x86/core' into x86/mce2 2009-02-24 16:11:51 -08:00
H. Peter Anvin
2aaa822984 Merge branch 'x86/defconfig' into x86/mce2
Conflicts (resolved):
	arch/x86/configs/x86_64_defconfig

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-02-24 16:01:17 -08:00
H. Peter Anvin
15d4fcd615 x86, mce: enable machine checks in 32-bit defconfig
Impact: defconfig change

Enable MCE in the 32-bit defconfig.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-02-24 15:52:58 -08:00
Andi Kleen
1250fbed14 x86, mce: enable machine checks in 64-bit defconfig
Impact: defconfig change

Enable MCE in the 64-bit defconfig.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2009-02-24 15:52:21 -08:00
Yinghai Lu
46cb27f516 x86: check range in reserve_early()
Impact: cleanup

one 32-bit system reports:

BIOS-provided physical RAM map:
 BIOS-e820: 0000000000000000 - 000000000009fc00 (usable)
 BIOS-e820: 000000000009fc00 - 00000000000a0000 (reserved)
 BIOS-e820: 00000000000f0000 - 0000000000100000 (reserved)
 BIOS-e820: 0000000000100000 - 000000001c000000 (usable)
 BIOS-e820: 00000000ffff0000 - 0000000100000000 (reserved)
DMI 2.0 present.
last_pfn = 0x1c000 max_arch_pfn = 0x100000
kernel direct mapping tables up to 1c000000 @ 7000-c000
..
RAMDISK: 1bc69000 - 1bfef4fa
..
0MB HIGHMEM available.
448MB LOWMEM available.
  mapped low ram: 0 - 1c000000
  low ram: 00000000 - 1c000000
  bootmap 00002000 - 00005800
(9 early reservations) ==> bootmem [0000000000 - 001c000000]
  #0 [0000000000 - 0000001000]   BIOS data page ==> [0000000000 - 0000001000]
  #1 [0000001000 - 0000002000]    EX TRAMPOLINE ==> [0000001000 - 0000002000]
  #2 [0000006000 - 0000007000]       TRAMPOLINE ==> [0000006000 - 0000007000]
  #3 [0000400000 - 00009ed14c]    TEXT DATA BSS ==> [0000400000 - 00009ed14c]
  #4 [001bc69000 - 001bfef4fa]          RAMDISK ==> [001bc69000 - 001bfef4fa]
  #5 [00009ee000 - 00009f2000]    INIT_PG_TABLE ==> [00009ee000 - 00009f2000]
  #6 [000009f400 - 0000100000]    BIOS reserved ==> [000009f400 - 0000100000]
  #7 [0000007000 - 0000007000]          PGTABLE
  #8 [0000002000 - 0000006000]          BOOTMAP ==> [0000002000 - 0000006000]

Notice the strange blank PGTABLE entry.

The reason is init_pg_table is big enough, and zero range is called
with init_memory_mapping/reserve_early().

So try to check the range in reserve_early()

v2: fix the reversed compare

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: nickpiggin@yahoo.com.au
Cc: ink@jurassic.park.msu.ru
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-24 22:43:15 +01:00
Andi Kleen
be71b8553d x86, mce, cmci: recheck CMCI banks after APIC has been enabled on CPU #0
Impact: Fix marginal race condition

One the first CPU the machine checks are enabled early before
the local APIC is enabled. This could in theory lead
to some lost CMCI events very early during boot because
CMCIs cannot be delivered with disabled LAPIC.

The poller also doesn't recover from this because it doesn't
check CMCI banks.

Add an explicit CMCI banks check after the LAPIC is enabled.
This is only done for CPU #0, the other CPUs only initialize
machine checks after the LAPIC is on.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-02-24 13:41:01 -08:00
Andi Kleen
5ca8681ca1 x86, mce, cmci: disable CMCI on rebooting
Impact: Avoids confusing other OSes.

Disable the CMCI vector on reboot to avoid confusing other OS.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-02-24 13:41:01 -08:00
H. Peter Anvin
df20e2eb3e x86, mce, cmci: remove incorrect __cpuinit/__cpuexit annotations
Impact: Bug fix on UP

The MCE code is reinitialized from resume, so we can't use
__cpuinit/__cpuexit for most of the code.  Remove those annotations
for anything downstream of mce_init().

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-02-24 13:41:01 -08:00
Andi Kleen
88ccbedd9c x86, mce, cmci: add CMCI support
Impact: Major new feature

Intel CMCI (Corrected Machine Check Interrupt) is a new
feature on Nehalem CPUs. It allows the CPU to trigger
interrupts on corrected events, which allows faster
reaction to them instead of with the traditional
polling timer.

Also use CMCI to discover shared banks. Machine check banks
can be shared by CPU threads or even cores. Using the CMCI enable
bit it is possible to detect the fact that another CPU already
saw a specific bank. Use this to assign shared banks only
to one CPU to avoid reporting duplicated events.

On CPU hot unplug bank sharing is re discovered. This is done
using a thread that cycles through all the CPUs.

To avoid races between the poller and CMCI we only poll
for banks that are not CMCI capable and only check CMCI
owned banks on a interrupt.

The shared banks ownership information is currently only used for
CMCI interrupts, not polled banks.

The sharing discovery code follows the algorithm recommended in the
IA32 SDM Vol3a 14.5.2.1

The CMCI interrupt handler just calls the machine check poller to
pick up the machine check event that caused the interrupt.

I decided not to implement a separate threshold event like
the AMD version has, because the threshold is always one currently
and adding another event didn't seem to add any value.

Some code inspired by Yunhong Jiang's Xen implementation,
which was in term inspired by a earlier CMCI implementation
by me.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-02-24 13:41:00 -08:00
Andi Kleen
03195c6b40 x86, mce, cmci: define MSR names and fields for new CMCI registers
Impact: New register definitions only

CMCI means support for raising an interrupt on a corrected machine
check event instead of having to poll for it. It's a new feature in
Intel Nehalem CPUs available on some machine check banks.

For details see the IA32 SDM Vol3a 14.5

Define the registers for it as a preparation for further patches.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-02-24 13:41:00 -08:00
Andi Kleen
ee031c31d6 x86, mce, cmci: use polled banks bitmap in machine check poller
Define a per cpu bitmap that contains the banks polled by the machine
check poller. This is needed for the CMCI code in the next patches
to be able to disable polling on specific banks.

The bank by default contains all banks, so there is no behaviour
change. Only future code will remove some banks from the polling
set.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-02-24 13:26:05 -08:00
Andi Kleen
8457c84d68 x86, mce: replace machine check events logged interval with ratelimit
Impact: behavior change, use common code

Use a standard leaky bucket ratelimit for the machine check
warning print interval instead of waiting every check_interval.
Also decrease the limit to twice per minute.
This interacts better with threshold interrupts because
they can happen more often than check_interval.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-02-24 13:25:53 -08:00
Andi Kleen
f9695df42c x86, mce, cmci: avoid potential reentry of threshold interrupt
Impact: minor bugfix

The threshold handler on AMD (and soon on Intel) could be theoretically
reentered by the hardware. This could lead to corrupted events
because the machine check poll code assumes it is not reentered.

Move the APIC ACK to the end of the interrupt handler to let
the hardware avoid that.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-02-24 13:24:42 -08:00
Andi Kleen
b276268631 x86, mce, cmci: factor out threshold interrupt handler
Impact: cleanup; preparation for feature

The mce_amd_64 code has an own private MC threshold vector with an own
interrupt handler. Since Intel needs a similar handler
it makes sense to share the vector because both can not
be active at the same time.

I factored the common APIC handler code into a separate file which can
be used by both the Intel or AMD MC code.

This is needed for the next patch which adds an Intel specific
CMCI handler.

This patch should be a nop for AMD, it just moves some code
around.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-02-24 13:24:42 -08:00
Andi Kleen
41fdff322e x86, mce, cmci: export MAX_NR_BANKS
Impact: Cleanup (code movement)

Move MAX_NR_BANKS into mce.h because it's needed there
for followup patches.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-02-24 13:24:42 -08:00
Jiri Slaby
b5f26d0556 x86_32: summit_32, de-inline functions
The ones which go only into struct genapic are de-inlined
by compiler anyway, so remove the inline specifier from them.

Afterwards, remove summit_setup_portio_remap completely as it
is unused.

Remove inline also from summit_cpu_mask_to_apicid, since it's
not worth it (it is used in struct genapic too).

Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-24 22:07:51 +01:00
Jiri Slaby
10b614eaa8 x86_32: summit_32, use BAD_APICID
Use BAD_APICID instead of 0xFF constants in summit_cpu_mask_to_apicid.

Also remove bogus comments about what we actually return.

Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-24 22:07:51 +01:00
Ingo Molnar
0edcf8d692 Merge branch 'tj-percpu' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/misc into core/percpu
Conflicts:
	arch/x86/include/asm/pgtable.h
2009-02-24 21:52:45 +01:00
Ingo Molnar
a852cbfaaf Merge branches 'x86/acpi', 'x86/apic', 'x86/asm', 'x86/cleanups', 'x86/mm', 'x86/signal' and 'x86/urgent'; commit 'v2.6.29-rc6' into x86/core 2009-02-24 21:50:43 +01:00
James Bottomley
ddf9499b3d x86, Voyager: fix compile by lifting the degeneracy of phys_cpu_present_map
This was changed to a physmap_t giving a clashing symbol redefinition,
but actually using a physmap_t consumes rather a lot of space on x86,
so stick with a private copy renamed with a voyager_ prefix and made
static.  Nothing outside of the Voyager code uses it, anyway.

Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-02-24 12:50:11 -08:00
Cyrill Gorcunov
9f331119a4 x86: efi_stub_32,64 - add missing ENDPROCs
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: heukelum@fastmail.fm
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-24 18:08:40 +01:00
Cyrill Gorcunov
bc8b2b9258 x86: head_64.S - use GLOBAL macro
Impact: cleanup

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: heukelum@fastmail.fm
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-24 18:08:40 +01:00
Cyrill Gorcunov
b3baaa138c x86: entry_64.S - add missing ENDPROC
native_usergs_sysret64 is described as

	extern void native_usergs_sysret64(void)

so lets add ENDPROC here

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: heukelum@fastmail.fm
Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-24 18:08:39 +01:00
Cyrill Gorcunov
57e372932c x86: invalid_vm86_irq -- use predefined macros
Impact: cleanup

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: heukelum@fastmail.fm
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-24 18:08:39 +01:00
Cyrill Gorcunov
5e112ae23b x86: head_64.S - use IDT_ENTRIES instead of hardcoded number
Impact: cleanup

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: heukelum@fastmail.fm
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-24 18:08:38 +01:00
Cyrill Gorcunov
2a0b100111 x86: head_64.S - remove useless balign
Impact: cleanup

NEXT_PAGE already has 'balign' so no
need to keep this redundant one.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: heukelum@fastmail.fm
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-24 18:08:38 +01:00
Salman Qazi
30d697fa3a x86: fix performance regression in write() syscall
While the introduction of __copy_from_user_nocache (see commit:
0812a579c9) may have been an improvement
for sufficiently large writes, there is evidence to show that it is
deterimental for small writes.  Unixbench's fstime test gives the
following results for 256 byte writes with MAX_BLOCK of 2000:

    2.6.29-rc6 ( 5 samples, each in KB/sec ):
    283750, 295200, 294500, 293000, 293300

    2.6.29-rc6 + this patch (5 samples, each in KB/sec):
    313050, 3106750, 293350, 306300, 307900

    2.6.18
    395700, 342000, 399100, 366050, 359850

    See w_test() in src/fstime.c in unixbench version 4.1.0.  Basically, the above test
    consists of counting how much we can write in this manner:

    alarm(10);
    while (!sigalarm) {
            for (f_blocks = 0; f_blocks < 2000; ++f_blocks) {
                   write(f, buf, 256);
            }
            lseek(f, 0L, 0);
    }

Note, there are other components to the write syscall regression
that are not addressed here.

Signed-off-by: Salman Qazi <sqazi@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-24 17:16:36 +01:00