Impact: clean up
We can autodetect those system that need cluster apic, and update genapic
accordingly.
We can also remove wakeup.h for e7000, because it's default one is now
the same as overall default mach_wakecpu.h
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fixes korg bugzilla 11980
A kernel for a 64bit x86 system should always contain the swiotlb code
in case it is booted on a machine without any hardware IOMMU supported
by the kernel and more than 4GB of RAM. This patch changes Kconfig to
always compile swiotlb into the kernel for x86_64.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Cc: stable@kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
My previous patch to make CONFIG_NUMA on x86_32 depend on BROKEN
turned out to be unnecessary, after all, since the source of the
hibernation vs CONFIG_NUMA problem turned out to be the fact that
we didn't take the NUMA KVA remapping into account in the
hibernation code.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: documentation update
Chris Snook pointed out that it's Core i7, not Core 7i.
Reported-by: Chris Snook <csnook@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: build/boot fix for x86/Voyager
This change:
| commit 3d44223327
| Author: Jens Axboe <jens.axboe@oracle.com>
| Date: Thu Jun 26 11:21:34 2008 +0200
|
| Add generic helpers for arch IPI function calls
didn't wire up the voyager smp call function correctly, so do that
here. Also make CONFIG_USE_GENERIC_SMP_HELPERS a def_bool y again,
since we now use the generic helpers for every x86 architecture.
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Jens Axboe <Jens.Axboe@oracle.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: add infrastructure for function-return tracing
Add low level support for ftrace return tracing.
This plug-in stores return addresses on the thread_info structure of
the current task.
The index of the current return address is initialized when the task
is the first one (init) and when a process forks (the child). It is
not needed when a task does a sys_execve because after this syscall,
it still needs to return on the kernel functions it called.
Note that the code of return_to_handler has been suggested by Steven
Rostedt as almost all of the ideas of improvements in this V3.
For purpose of security, arch/x86/kernel/process_32.c is not traced
because __switch_to() changes the current task during its execution.
That could cause inconsistency in the stored return address of this
function even if I didn't have any crash after testing with tracing on
this function enabled.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup, change .config option name
We had this ugly config name for a long time for hysteric raisons.
Rename it to a saner name.
We still cannot get rid of it completely, until /proc/<pid>/stack
usage replaces WCHAN usage for good.
We'll be able to do that in the v2.6.29/v2.6.30 timeframe.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
While investigating the failure of hibernation on 32-bit x86 with
CONFIG_NUMA set, as described in this message
http://marc.info/?l=linux-kernel&m=122634118116226&w=4
I asked some people for help and I was told that it wasn't really
worth the effort, because CONFIG_NUMA was generally broken on 32-bit
x86 systems and it shouldn't be used in such configs. For this
reason, make CONFIG_NUMA depend on BROKEN instead of EXPERIMENTAL on
x86-32.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Pavel Machek <pavel@suse.cz>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
Revert "x86: default to reboot via ACPI"
x86: align DirectMap in /proc/meminfo
AMD IOMMU: fix lazy IO/TLB flushing in unmap path
x86: add smp_mb() before sending INVALIDATE_TLB_VECTOR
x86: remove VISWS and PARAVIRT around NR_IRQS puzzle
x86: mention ACPI in top-level Kconfig menu
x86: size NR_IRQS on 32-bit systems the same way as 64-bit
x86: don't allow nr_irqs > NR_IRQS
x86/docs: remove noirqbalance param docs
x86: don't use tsc_khz to calculate lpj if notsc is passed
x86, voyager: fix smp_intr_init() compile breakage
AMD IOMMU: fix detection of NP capable IOMMUs
Enable the wchan config menu item for now on x86-64 arch? This will
at least allow people to enable/disable frame pointers on scheduler
functions.
Signed-off-by: Ken Chen <kenchen@google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: clarify/update CONFIG_NUMA text
CONFIG_NUMA description talk about a bit old thing.
So, following changes are better.
o CONFIG_NUMA is no longer EXPERIMENTAL
o Opteron is not the only processor of NUMA topology on x86_64 no longer,
but also Intel Core7i has it.
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: clarify menuconfig text
Mention ACPI in the top-level menu to give a clue as to where
it lives. This matches what ia64 does.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: quick start and stop of function tracer
This patch adds a way to disable the function tracer quickly without
the need to run kstop_machine. It adds a new variable called
function_trace_stop which will stop the calls to functions from mcount
when set. This is just an on/off switch and does not handle recursion
like preempt_disable().
It's main purpose is to help other tracers/debuggers start and stop tracing
fuctions without the need to call kstop_machine.
The config option HAVE_FUNCTION_TRACE_MCOUNT_TEST is added for archs
that implement the testing of the function_trace_stop in the mcount
arch dependent code. Otherwise, the test is done in the C code.
x86 is the only arch at the moment that supports this.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
clean up ifdefs: change #ifdef CONFIG_X86_32/64 to
CONFIG_HAVE_ATOMIC_IOMAP.
flip around the #ifdef sections to clean up the structure.
Signed-off-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: enable CONFIG_MEMORY_HOTREMOVE feature on x86. (default-off)
Memory hotremove functionality can currently be configured into
the ia64, powerpc, and s390 kernels.
This patch makes it possible to configure the memory hotremove
functionality into the x86 kernel as well.
Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>
Signed-off-by: Gary Hade <garyhade@us.ibm.com>
Signed-off-by: Ingo 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: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
DIRECT_GBPAGES was under DEBUG_KERNEL && EXPERIMENTAL and disabled by default.
Turn it on by default and put it under EMBEDDED.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The Intel 7300 Memory Controller supports dynamic throttling of memory which can
be used to save power when system is idle. This driver does the memory
throttling when all CPUs are idle on such a system.
Refer to "Intel 7300 Memory Controller Hub (MCH)" datasheet
for the config space description.
Signed-off-by: Andy Henroid <andrew.d.henroid@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
This merges branches irq/genirq, irq/sparseirq-v4, timers/hpet-percpu
and x86/uv.
The sparseirq branch is just preliminary groundwork: no sparse IRQs are
actually implemented by this tree anymore - just the new APIs are added
while keeping the old way intact as well (the new APIs map 1:1 to
irq_desc[]). The 'real' sparse IRQ support will then be a relatively
small patch ontop of this - with a v2.6.29 merge target.
* 'genirq-v28-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (178 commits)
genirq: improve include files
intr_remapping: fix typo
io_apic: make irq_mis_count available on 64-bit too
genirq: fix name space collisions of nr_irqs in arch/*
genirq: fix name space collision of nr_irqs in autoprobe.c
genirq: use iterators for irq_desc loops
proc: fixup irq iterator
genirq: add reverse iterator for irq_desc
x86: move ack_bad_irq() to irq.c
x86: unify show_interrupts() and proc helpers
x86: cleanup show_interrupts
genirq: cleanup the sparseirq modifications
genirq: remove artifacts from sparseirq removal
genirq: revert dynarray
genirq: remove irq_to_desc_alloc
genirq: remove sparse irq code
genirq: use inline function for irq_to_desc
genirq: consolidate nr_irqs and for_each_irq_desc()
x86: remove sparse irq from Kconfig
genirq: define nr_irqs for architectures with GENERIC_HARDIRQS=n
...
Due to confusion between the ftrace infrastructure and the gcc profiling
tracer "ftrace", this patch renames the config options from FTRACE to
FUNCTION_TRACER. The other two names that are offspring from FTRACE
DYNAMIC_FTRACE and FTRACE_MCOUNT_RECORD will stay the same.
This patch was generated mostly by script, and partially by hand.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This patch implements a new freezer subsystem in the control groups
framework. It provides a way to stop and resume execution of all tasks in
a cgroup by writing in the cgroup filesystem.
The freezer subsystem in the container filesystem defines a file named
freezer.state. Writing "FROZEN" to the state file will freeze all tasks
in the cgroup. Subsequently writing "RUNNING" will unfreeze the tasks in
the cgroup. Reading will return the current state.
* Examples of usage :
# mkdir /containers/freezer
# mount -t cgroup -ofreezer freezer /containers
# mkdir /containers/0
# echo $some_pid > /containers/0/tasks
to get status of the freezer subsystem :
# cat /containers/0/freezer.state
RUNNING
to freeze all tasks in the container :
# echo FROZEN > /containers/0/freezer.state
# cat /containers/0/freezer.state
FREEZING
# cat /containers/0/freezer.state
FROZEN
to unfreeze all tasks in the container :
# echo RUNNING > /containers/0/freezer.state
# cat /containers/0/freezer.state
RUNNING
This is the basic mechanism which should do the right thing for user space
task in a simple scenario.
It's important to note that freezing can be incomplete. In that case we
return EBUSY. This means that some tasks in the cgroup are busy doing
something that prevents us from completely freezing the cgroup at this
time. After EBUSY, the cgroup will remain partially frozen -- reflected
by freezer.state reporting "FREEZING" when read. The state will remain
"FREEZING" until one of these things happens:
1) Userspace cancels the freezing operation by writing "RUNNING" to
the freezer.state file
2) Userspace retries the freezing operation by writing "FROZEN" to
the freezer.state file (writing "FREEZING" is not legal
and returns EIO)
3) The tasks that blocked the cgroup from entering the "FROZEN"
state disappear from the cgroup's set of tasks.
[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: export thaw_process]
Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Signed-off-by: Matt Helsley <matthltc@us.ibm.com>
Acked-by: Serge E. Hallyn <serue@us.ibm.com>
Tested-by: Matt Helsley <matthltc@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Using "def_bool n" is pointless, simply using bool here appears more
appropriate.
Further, retaining such options that don't have a prompt and aren't
selected by anything seems also at least questionable.
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Ingo said sparse_irq is some intrusive. need to make it selectable
to make it simple, remove irq_desc as parameter in some functions.
(ack, eoi, set_affinity).
may need to make member if irq_chip to take irq_desc, or struct irq later.
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
but actually irq still needs to be less than NR_IRQS, because
interrupt[NR_IRQS] in entry.S.
need to enable per_cpu vector...
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This has been deprecated for years, the user space irqbalanced utility
works better with numa, has configurable policies, etc...
Signed-off-by: Yinghai Lu <yhlu.kernel@gmai.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
add CONFIG_HAVE_SPARSE_IRQ to for use condensed array.
Get rid of irq_desc[] array assumptions.
Preallocate 32 irq_desc, and irq_desc() will try to get more.
( No change in functionality is expected anywhere, except the odd build
failure where we missed a code site or where a crossing commit itroduces
new irq_desc[] usage. )
v2: according to Eric, change get_irq_desc() to irq_desc()
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Enable the use of the __mcount_loc infrastructure on x86_64 and i386.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Combine both generic and arch-specific parts of microcode into a
single module (arch-specific parts are config-dependent).
Also while we are at it, move arch-specific parts from microcode.h
into their respective arch-specific .c files.
Signed-off-by: Dmitry Adamushko <dmitry.adamushko@gmail.com>
Cc: "Peter Oruba" <peter.oruba@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The AMD IOMMU can generate interrupts for various reasons. This patch
adds the basic interrupt enabling infrastructure to the driver.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This bugzilla:
http://bugzilla.kernel.org/show_bug.cgi?id=11237
Documents a wide range of systems where the BIOS utilizes the first
64K of physical memory during suspend/resume and other hardware events.
Currently we reserve this memory on all AMI and Phoenix BIOS systems.
Life is too short to hunt subtle memory corruption problems like this,
so we try to be robust by default.
Still, allow this to be overriden: allow users who want that first 64K
of memory to be available to the kernel disable the quirk, via
CONFIG_X86_RESERVE_LOW_64K=n.
Also, allow the early reservation to overlap with other
early reservations.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
There's no good reason why a resource_size_t shouldn't just be a
physical address, so simply redefine it in terms of phys_addr_t.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Add a kernel-wide "phys_addr_t" which is guaranteed to be able to hold
any physical address. By default it equals the word size of the
architecture, but a 32-bit architecture can set ARCH_PHYS_ADDR_T_64BIT
if it needs a 64-bit phys_addr_t.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Default the low memory corruption check to off, but make the default setting of
the memory_corruption_check kernel parameter a config parameter.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The corruption check is enabled in Kconfig by default, but disabled at runtime.
This patch adds several kernel parameters to control the corruption
check's behaviour; these are documented in kernel-parameters.txt.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Some BIOSes have been observed to corrupt memory in the low 64k. This
change:
- Reserves all memory which does not have to be in that area, to
prevent it from being used as general memory by the kernel. Things
like the SMP trampoline are still in the memory, however.
- Clears the reserved memory so we can observe changes to it.
- Adds a function check_for_bios_corruption() which checks and reports on
memory becoming unexpectedly non-zero. Currently it's called in the
x86 fault handler, and the powermanagement debug output.
Signed-off-by: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
HAVE_AOUT doesn't quite do the same thing as the recently removed
ARCH_SUPPORTS_AOUT config option. That was set even on platforms where
binfmt_aout isn't supported, although it's not entirely clear why.
So it's best just to introduce a new symbol, handled consistently with
other similar HAVE_xxx symbols; with a simple 'select' in the arch Kconfig.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
This fixes a regression that was indirectly caused by commit
1184dc2ffe ("x86: modify Kconfig to allow
up to 4096 cpus").
Allowing 4k CPU's is not practical at this time, because we still have a
number of places that have several 'cpumask_t's on the stack, and a
4k-bit cpumask is 512 bytes of stack-space for each such variable. This
literally caused functions like 'smp_call_function_mask' to have a 2.5kB
stack frame, and several functions to have 2kB stackframes.
With an 8kB stack total, smashing the stack was simply much too likely.
At least bugzilla entry
http://bugzilla.kernel.org/show_bug.cgi?id=11342
was due to this.
The earlier commit to not inline load_module() into sys_init_module()
fixed the particular symptoms of this that Alan Brunelle saw in that
bugzilla entry, but the huge stack waste by cpumask_t's was the more
direct cause.
Some day we'll have allocation helpers that allocate large CPU masks
dynamically, but in the meantime we simply cannot allow cpumasks this
large.
Cc: Alan D. Brunelle <Alan.Brunelle@hp.com>
Cc: Mike Travis <travis@sgi.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Allow x86 to support a built-in kernel command line. The built-in
command line can override the one provided by the boot loader, for
those cases where the boot loader is broken or it is difficult
to change the command line in the the boot loader.
H. Peter Anvin wrote:
> Ingo Molnar wrote:
>> Best would be to make it really apparent in the code that nothing
>> changes if this config option is not set. Preferably there should be
>> no extra code at all in that case.
>>
>
> I would like to see this:
[...Nested ifdefs...]
OK. This version changes absolutely nothing if CONFIG_CMDLINE_BOOL is not
set (the default). Also, no space is appended even when CONFIG_CMDLINE_BOOL
is set, but the builtin string is empty. This is less sloppy all the way
around, IMHO.
Note that I use the same option names as on other arches for
this feature.
[ mingo@elte.hu: build fix ]
Signed-off-by: Tim Bird <tim.bird@am.sony.com>
Cc: Matt Mackall <mpm@selenic.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Adjust experimental tags in Kconfig, update config to notice that
i386/x86_64 is now single architecture.
Signed-off-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Out of line get_user_pages_fast fallback implementation, make it a weak
symbol, get rid of CONFIG_HAVE_GET_USER_PAGES_FAST.
Export the symbol to modules so lguest can use it.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
With CONFIG_X86_PC, I can set CONFIG_SPARSEMEM=y.
With CONFIG_X86_GENERICARCH, CONFIG_SPARSEMEM depends on CONFIG_NUMA.
I'm using the patch below to enable sparsemem instead of flatmem.
System booted and is running.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This removes the EXPERIMENTAL restriction from CONFIG_HOTPLUG_CPU
on the x86 architecture.
Signed-off-by: Dimitri Sivanich <sivanich@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This patch introduces microcode patch loading for AMD
processors. It is based on previous corresponding work
for Intel processors.
It hooks into the general patch loading module. Main
difference is that a container file format is used to hold
all patch data for multiple processors as well as an
equivalent CPU table, which comes seperately, as opposed
to Intel's microcode patching solution.
Kconfig and Makefile have been changed provice config
and build option for new source file.
Signed-off-by: Peter Oruba <peter.oruba@amd.com>
Cc: Tigran Aivazian <tigran@aivazian.fsnet.co.uk>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Refactored code by introducing a two-module solution.
There is one general module in which vendor specific modules can hook into.
However, that is exclusive, there is only one vendor specific module
allowed at a time. A CPU vendor check makes sure only the correct
module for the underlying system gets called.
Functinally in terms of patch loading itself there are no changes. This
refactoring provides a basis for future implementations of other vendors'
patch loaders.
Signed-off-by: Peter Oruba <peter.oruba@amd.com>
Cc: Tigran Aivazian <tigran@aivazian.fsnet.co.uk>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Move mtrr.txt to the Documentation/x86/ subdirectory.
Add 00-INDEX to the Documentation/x86/ subdirectory.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86, AMD IOMMU: include amd_iommu_last_bdf in device initialization
x86: fix IBM Summit based systems' phys_cpu_present_map on 32-bit kernels
x86, RDC321x: remove gpio.h complications
x86, RDC321x: add to mach-default
crashdump: fix undefined reference to `elfcorehdr_addr'
flag parameters: fix compile error of sys_epoll_create1
Implement get_user_pages_fast without locking in the fastpath on x86.
Do an optimistic lockless pagetable walk, without taking mmap_sem or any
page table locks or even mmap_sem. Page table existence is guaranteed by
turning interrupts off (combined with the fact that we're always looking
up the current mm, means we can do the lockless page table walk within the
constraints of the TLB shootdown design). Basically we can do this
lockless pagetable walk in a similar manner to the way the CPU's pagetable
walker does not have to take any locks to find present ptes.
This patch (combined with the subsequent ones to convert direct IO to use
it) was found to give about 10% performance improvement on a 2 socket 8
core Intel Xeon system running an OLTP workload on DB2 v9.5
"To test the effects of the patch, an OLTP workload was run on an IBM
x3850 M2 server with 2 processors (quad-core Intel Xeon processors at
2.93 GHz) using IBM DB2 v9.5 running Linux 2.6.24rc7 kernel. Comparing
runs with and without the patch resulted in an overall performance
benefit of ~9.8%. Correspondingly, oprofiles showed that samples from
__up_read and __down_read routines that is seen during thread contention
for system resources was reduced from 2.8% down to .05%. Monitoring the
/proc/vmstat output from the patched run showed that the counter for
fast_gup contained a very high number while the fast_gup_slow value was
zero."
(fast_gup is the old name for get_user_pages_fast, fast_gup_slow is a
counter we had for the number of times the slowpath was invoked).
The main reason for the improvement is that DB2 has multiple threads each
issuing direct-IO. Direct-IO uses get_user_pages, and thus the threads
contend the mmap_sem cacheline, and can also contend on page table locks.
I would anticipate larger performance gains on larger systems, however I
think DB2 uses an adaptive mix of threads and processes, so it could be
that thread contention remains pretty constant as machine size increases.
In which case, we stuck with "only" a 10% gain.
The downside of using get_user_pages_fast is that if there is not a pte
with the correct permissions for the access, we end up falling back to
get_user_pages and so the get_user_pages_fast is a bit of extra work.
However this should not be the common case in most performance critical
code.
[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: build fix]
[akpm@linux-foundation.org: Kconfig fix]
[akpm@linux-foundation.org: Makefile fix/cleanup]
[akpm@linux-foundation.org: warning fix]
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Dave Kleikamp <shaggy@austin.ibm.com>
Cc: Andy Whitcroft <apw@shadowen.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Dave Kleikamp <shaggy@austin.ibm.com>
Cc: Badari Pulavarty <pbadari@us.ibm.com>
Cc: Zach Brown <zach.brown@oracle.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Reviewed-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch implements devices state save/restore before after kexec.
This patch together with features in kexec_jump patch can be used for
following:
- A simple hibernation implementation without ACPI support. You can kexec a
hibernating kernel, save the memory image of original system and shutdown
the system. When resuming, you restore the memory image of original system
via ordinary kexec load then jump back.
- Kernel/system debug through making system snapshot. You can make system
snapshot, jump back, do some thing and make another system snapshot.
- Cooperative multi-kernel/system. With kexec jump, you can switch between
several kernels/systems quickly without boot process except the first time.
This appears like swap a whole kernel/system out/in.
- A general method to call program in physical mode (paging turning
off). This can be used to invoke BIOS code under Linux.
The following user-space tools can be used with kexec jump:
- kexec-tools needs to be patched to support kexec jump. The patches
and the precompiled kexec can be download from the following URL:
source: http://khibernation.sourceforge.net/download/release_v10/kexec-tools/kexec-tools-src_git_kh10.tar.bz2
patches: http://khibernation.sourceforge.net/download/release_v10/kexec-tools/kexec-tools-patches_git_kh10.tar.bz2
binary: http://khibernation.sourceforge.net/download/release_v10/kexec-tools/kexec_git_kh10
- makedumpfile with patches are used as memory image saving tool, it
can exclude free pages from original kernel memory image file. The
patches and the precompiled makedumpfile can be download from the
following URL:
source: http://khibernation.sourceforge.net/download/release_v10/makedumpfile/makedumpfile-src_cvs_kh10.tar.bz2
patches: http://khibernation.sourceforge.net/download/release_v10/makedumpfile/makedumpfile-patches_cvs_kh10.tar.bz2
binary: http://khibernation.sourceforge.net/download/release_v10/makedumpfile/makedumpfile_cvs_kh10
- An initramfs image can be used as the root file system of kexeced
kernel. An initramfs image built with "BuildRoot" can be downloaded
from the following URL:
initramfs image: http://khibernation.sourceforge.net/download/release_v10/initramfs/rootfs_cvs_kh10.gz
All user space tools above are included in the initramfs image.
Usage example of simple hibernation:
1. Compile and install patched kernel with following options selected:
CONFIG_X86_32=y
CONFIG_RELOCATABLE=y
CONFIG_KEXEC=y
CONFIG_CRASH_DUMP=y
CONFIG_PM=y
CONFIG_HIBERNATION=y
CONFIG_KEXEC_JUMP=y
2. Build an initramfs image contains kexec-tool and makedumpfile, or
download the pre-built initramfs image, called rootfs.gz in
following text.
3. Prepare a partition to save memory image of original kernel, called
hibernating partition in following text.
4. Boot kernel compiled in step 1 (kernel A).
5. In the kernel A, load kernel compiled in step 1 (kernel B) with
/sbin/kexec. The shell command line can be as follow:
/sbin/kexec --load-preserve-context /boot/bzImage --mem-min=0x100000
--mem-max=0xffffff --initrd=rootfs.gz
6. Boot the kernel B with following shell command line:
/sbin/kexec -e
7. The kernel B will boot as normal kexec. In kernel B the memory
image of kernel A can be saved into hibernating partition as
follow:
jump_back_entry=`cat /proc/cmdline | tr ' ' '\n' | grep kexec_jump_back_entry | cut -d '='`
echo $jump_back_entry > kexec_jump_back_entry
cp /proc/vmcore dump.elf
Then you can shutdown the machine as normal.
8. Boot kernel compiled in step 1 (kernel C). Use the rootfs.gz as
root file system.
9. In kernel C, load the memory image of kernel A as follow:
/sbin/kexec -l --args-none --entry=`cat kexec_jump_back_entry` dump.elf
10. Jump back to the kernel A as follow:
/sbin/kexec -e
Then, kernel A is resumed.
Implementation point:
To support jumping between two kernels, before jumping to (executing)
the new kernel and jumping back to the original kernel, the devices
are put into quiescent state, and the state of devices and CPU is
saved. After jumping back from kexeced kernel and jumping to the new
kernel, the state of devices and CPU are restored accordingly. The
devices/CPU state save/restore code of software suspend is called to
implement corresponding function.
Known issues:
- Because the segment number supported by sys_kexec_load is limited,
hibernation image with many segments may not be load. This is
planned to be eliminated by adding a new flag to sys_kexec_load to
make a image can be loaded with multiple sys_kexec_load invoking.
Now, only the i386 architecture is supported.
Signed-off-by: Huang Ying <ying.huang@intel.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Nigel Cunningham <nigel@nigel.suspend2.net>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch provides an enhancement to kexec/kdump. It implements the
following features:
- Backup/restore memory used by the original kernel before/after
kexec.
- Save/restore CPU state before/after kexec.
The features of this patch can be used as a general method to call program in
physical mode (paging turning off). This can be used to call BIOS code under
Linux.
kexec-tools needs to be patched to support kexec jump. The patches and
the precompiled kexec can be download from the following URL:
source: http://khibernation.sourceforge.net/download/release_v10/kexec-tools/kexec-tools-src_git_kh10.tar.bz2
patches: http://khibernation.sourceforge.net/download/release_v10/kexec-tools/kexec-tools-patches_git_kh10.tar.bz2
binary: http://khibernation.sourceforge.net/download/release_v10/kexec-tools/kexec_git_kh10
Usage example of calling some physical mode code and return:
1. Compile and install patched kernel with following options selected:
CONFIG_X86_32=y
CONFIG_KEXEC=y
CONFIG_PM=y
CONFIG_KEXEC_JUMP=y
2. Build patched kexec-tool or download the pre-built one.
3. Build some physical mode executable named such as "phy_mode"
4. Boot kernel compiled in step 1.
5. Load physical mode executable with /sbin/kexec. The shell command
line can be as follow:
/sbin/kexec --load-preserve-context --args-none phy_mode
6. Call physical mode executable with following shell command line:
/sbin/kexec -e
Implementation point:
To support jumping without reserving memory. One shadow backup page (source
page) is allocated for each page used by kexeced code image (destination
page). When do kexec_load, the image of kexeced code is loaded into source
pages, and before executing, the destination pages and the source pages are
swapped, so the contents of destination pages are backupped. Before jumping
to the kexeced code image and after jumping back to the original kernel, the
destination pages and the source pages are swapped too.
C ABI (calling convention) is used as communication protocol between
kernel and called code.
A flag named KEXEC_PRESERVE_CONTEXT for sys_kexec_load is added to
indicate that the loaded kernel image is used for jumping back.
Now, only the i386 architecture is supported.
Signed-off-by: Huang Ying <ying.huang@intel.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Nigel Cunningham <nigel@nigel.suspend2.net>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Ingo Molnar
Yinghai Lu
Joerg Roedel
Rafael J. Wysocki
James Bottomley
Frederic Weisbecker
Linus Torvalds
Ken Chen
KOSAKI Motohiro
Bjorn Helgaas
Steven Rostedt
Keith Packard
Gary Hade
Jan Beulich
Len Brown
Nick Piggin
Andy Henroid
Steven Rostedt
Matt Helsley
Venkatesh Pallipadi
Thomas Gleixner
Yinghai Lu
David Woodhouse
Dmitry Adamushko
Jeremy Fitzhardinge
Alexey Dobriyan
David Woodhouse
Tim Bird
Pavel Machek
Rusty Russell
Jeff Chua
Dimitri Sivanich
Peter Oruba
Randy Dunlap
Roland McGrath
Huang Ying