IA64 kdump kernel failed to initialize /proc/vmcore in 2.6.28-rc2.
A bug was introduced in this patch commit:
d9a9855d0b
always reserve elfcore header memory in crash kernel
The problem was that the call to reserve_elfcorehdr() should be placed
in CONFIG_CRASH_DUMP rather than in CONFIG_CRASH_KERNEL, which does
not exist.
Signed-off-by: Jay Lan <jlan@sgi.com>
Acked-by: Simon Hormon <horms@verge.net.au>
Signed-off-by: Tony Luck <tony.luck@intel.com>
This fixes a regression introduced by 2c6e6db41f
"Minimize per_cpu reservations." That patch incorrectly used information about
what CPUs are possible that was not yet initialized by ACPI. The end result
was that per_cpu structures for offline CPUs were not initialized causing a
NULL pointer reference.
Since we cannot do the full acpi_boot_init() call any earlier, the simplest
fix is to just parse the MADT for SAPIC entries early to find the CPU
info. This should also allow for some cleanup of the code added by the
"Minimize per_cpu reservations". This patch just fixes the regressions, the
cleanup will come in a later patch.
Signed-off-by: Doug Chapman <doug.chapman@hp.com>
Signed-off-by: Alex Chiang <achiang@hp.com>
CC: Robin Holt <holt@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
As it is, all instances of ->release() for files that have ->fasync()
need to remember to evict file from fasync lists; forgetting that
creates a hole and we actually have a bunch that *does* forget.
So let's keep our lives simple - let __fput() check FASYNC in
file->f_flags and call ->fasync() there if it's been set. And lose that
crap in ->release() instances - leaving it there is still valid, but we
don't have to bother anymore.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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: "Alexander Beregalov" <a.beregalov@gmail.com>
Acked-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
* 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux-2.6: (41 commits)
[IA64] Fix annoying IA64_TR_ALLOC_MAX message.
[IA64] kill sys32_pipe
[IA64] remove sys32_pause
[IA64] Add Variable Page Size and IA64 Support in Intel IOMMU
ia64/pv_ops: paravirtualized instruction checker.
ia64/xen: a recipe for using xen/ia64 with pv_ops.
ia64/pv_ops: update Kconfig for paravirtualized guest and xen.
ia64/xen: preliminary support for save/restore.
ia64/xen: define xen machine vector for domU.
ia64/pv_ops/xen: implement xen pv_time_ops.
ia64/pv_ops/xen: implement xen pv_irq_ops.
ia64/pv_ops/xen: define the nubmer of irqs which xen needs.
ia64/pv_ops/xen: implement xen pv_iosapic_ops.
ia64/pv_ops/xen: paravirtualize entry.S for ia64/xen.
ia64/pv_ops/xen: paravirtualize ivt.S for xen.
ia64/pv_ops/xen: paravirtualize DO_SAVE_MIN for xen.
ia64/pv_ops/xen: define xen paravirtualized instructions for hand written assembly code
ia64/pv_ops/xen: define xen pv_cpu_ops.
ia64/pv_ops/xen: define xen pv_init_ops for various xen initialization.
ia64/pv_ops/xen: elf note based xen startup.
...
elfcore header memory needs to be reserved in a crash kernel. This means
that the relevant code should be protected by CONFIG_CRASH_DUMP rather
than CONFIG_PROC_VMCORE.
Signed-off-by: Simon Horman <horms@verge.net.au>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The usage of elfcorehdr_addr has changed recently such that being set to
ELFCORE_ADDR_MAX is used by is_kdump_kernel() to indicate if the code is
executing in a kernel executed as a crash kernel.
However, arch/ia64/kernel/setup.c:reserve_elfcorehdr will rest
elfcorehdr_addr to ELFCORE_ADDR_MAX on error, which means any subsequent
calls to is_kdump_kernel() will return 0, even though they should return
1.
Ok, at this point in time there are no subsequent calls, but I think its
fair to say that there is ample scope for error or at the very least
confusion.
This patch add an extra state, ELFCORE_ADDR_ERR, which indicates that
elfcorehdr_addr was passed on the command line, and thus execution is
taking place in a crashdump kernel, but vmcore can't be used for some
reason. This is tested for using is_vmcore_usable() and set using
vmcore_unusable(). A subsequent patch makes use of this new code.
To summarise, the states that elfcorehdr_addr can now be in are as follows:
ELFCORE_ADDR_MAX: not a crashdump kernel
ELFCORE_ADDR_ERR: crashdump kernel but vmcore is unusable
any other value: crash dump kernel and vmcore is usable
Signed-off-by: Simon Horman <horms@verge.net.au>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
o elfcorehdr_addr is used by not only the code under CONFIG_PROC_VMCORE
but also by the code which is not inside CONFIG_PROC_VMCORE. For
example, is_kdump_kernel() is used by powerpc code to determine if
kernel is booting after a panic then use previous kernel's TCE table.
So even if CONFIG_PROC_VMCORE is not set in second kernel, one should be
able to correctly determine that we are booting after a panic and setup
calgary iommu accordingly.
o So remove the assumption that elfcorehdr_addr is under
CONFIG_PROC_VMCORE.
o Move definition of elfcorehdr_addr to arch dependent crash files.
(Unfortunately crash dump does not have an arch independent file
otherwise that would have been the best place).
o kexec.c is not the right place as one can Have CRASH_DUMP enabled in
second kernel without KEXEC being enabled.
o I don't see sh setup code parsing the command line for
elfcorehdr_addr. I am wondering how does vmcore interface work on sh.
Anyway, I am atleast defining elfcoredhr_addr so that compilation is not
broken on sh.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Simon Horman <horms@verge.net.au>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The patch contains Intel IOMMU IA64 specific code. It defines new
machvec dig_vtd, hooks for IOMMU, DMAR table detection, cache line flush
function, etc.
For a generic kernel with CONFIG_DMAR=y, if Intel IOMMU is detected,
dig_vtd is used for machinve vector. Otherwise, kernel falls back to
dig machine vector. Kernel parameter "machvec=dig" or "intel_iommu=off"
can be used to force kernel to boot dig machine vector.
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
This patch implements a checker to detect instructions which
should be paravirtualized instead of direct writing raw instruction.
This patch does rough check so that it doesn't fully cover all cases,
but it can detects most cases of paravirtualization breakage of hand
written assembly codes.
Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>
Signed-off-by: Tony Luck <tony.luck@intel.com>
define arch/ia64/include/asm/xen/irq.h to define the number of
irqs which xen needs.
Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>
Signed-off-by: Tony Luck <tony.luck@intel.com>
This patch enables elf note based xen startup for IA-64, which gives the
kernel an early hint for running on xen like x86 case.
In order to avoid the multi entry point, presumably extending booting
protocol(i.e. extending struct ia64_boot_param) would be necessary.
It probably means that elilo also needs modification.
Signed-off-by: Qing He <qing.he@intel.com>
Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>
Signed-off-by: Tony Luck <tony.luck@intel.com>
eliminate the function declaration ia64_cpu_local_tick() in
process.c by defining in arch/ia64/include/asm/timex.h
The same function will be used in a different .c file later.
Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>
Signed-off-by: Tony Luck <tony.luck@intel.com>
The macro get_irq_chip() is defined in linux/include/linux/irq.h
which cause name conflict with one in linux/arch/ia64/include/asm/paravirt.h.
rename the latter to __get_irq_chip().
Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>
Signed-off-by: Tony Luck <tony.luck@intel.com>
When CONFIG_SMP=n, three instruction in ivt.S were missed to paravirtualize.
paravirtualize them.
Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Initial fix for making sure that we can access percpu variables
in all C code (commit: 10617bbe84)
inadvertantly allocated the memory in the "percpu" section of
the vmlinux ELF executable. This confused kexec/dump.
Signed-off-by: Tony Luck <tony.luck@intel.com>
Currently a memory segment in memory map with attribute of EFI_MEMORY_UC
is denoted as "System RAM" in /proc/iomem, while memory of attribute
(EFI_MEMORY_WB|EFI_MEMORY_UC) is also labeled the same.
The kexec utility then includes uncached memory as part of vmcore. The
kdump kernel MCA'ed when it tries to save the vmcore to a disk. A normal
"cached" access may cause MCAs.
This patch would label memory with attribute of EFI_MEMORY_UC only as
"Uncached RAM" so that kexec would know not to include it in the vmcore.
I will submit a separate kexec-tools patch to the kexec list.
Signed-off-by: Jay Lan <jlan@sgi.com>
Acked-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Peter Chubb reported that commit 3463a93def
(Update check_sal_cache_flush to use platform_send_ipi()) broke
Ski because it does not implement IPIs.
Tony Luck suggested we just #ifndef out the call (since the simulator
does not have the SAL bug that this code is attempting to detect and
workaround)
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Make ia64 refrain from clearing a given to-be-offlined CPU's bit in the
cpu_online_mask until it has processed pending irqs. This change
prevents other CPUs from being blindsided by an apparently offline CPU
nevertheless changing globally visible state. Also remove the existing
redundant cpu_clear(cpu, cpu_online_map).
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Broke the non modular builds by moving an essential function into
modules.c. Fix this by moving it out again and into asm/sections.h as
an inline. To do this, the definitions of struct fdesc and struct
got_val have been lifted out of modules.c and put in asm/elf.h where
they belong.
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
It was introduced by "vsprintf: add support for '%pS' and '%pF' pointer
formats" in commit 0fe1ef24f7. However,
the current way its coded doesn't work on parisc64. For two reasons: 1)
parisc isn't in the #ifdef and 2) parisc has a different format for
function descriptors
Make dereference_function_descriptor() more accommodating by allowing
architecture overrides. I put the three overrides (for parisc64, ppc64
and ia64) in arch/kernel/module.c because that's where the kernel
internal linker which knows how to deal with function descriptors sits.
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Tony Luck <tony.luck@intel.com>
Acked-by: Kyle McMartin <kyle@mcmartin.ca>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Right now, there is no notifier that is called on a new cpu, before the new
cpu begins processing interrupts/softirqs.
Various kernel function would need that notification, e.g. kvm works around
by calling smp_call_function_single(), rcu polls cpu_online_map.
The patch adds a CPU_STARTING notification. It also adds a helper function
that sends the message to all cpu_chain handlers.
Tested on x86-64.
All other archs are untested. Especially on sparc, I'm not sure if I got
it right.
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
CONFIG_SFC=m uses topology_core_siblings() which, for ia64, expects
cpu_core_map to be exported. It is not. This patch exports the needed
symbol.
Maintainers note: This really looks like the wrong thing to do ... it
would be much better for the kernel to export an API to provide
drivers like this with data they need (which in the case of this
driver seems to be an estimate of the effective parallelism available
on the platform). But x86 has exported this forever ... so go with
the flow until such an API is defined.
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Signed-off-by: Robin Holt <holt@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Making allmodconfig will break the current build. This patch shrinks
the per_cpu__shadow_flush_counts from 16k to 8k which frees enough space
to allow allmodconfig to successfully complete.
Fixes http://bugzilla.kernel.org/show_bug.cgi?id=11338
Signed-off-by: Robin Holt <holt@sgi.com>
Acked-by: Jack Steiner <steiner@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
ia64 handles per-cpu variables a litle differently from other architectures
in that it maps the physical memory allocated for each cpu at a constant
virtual address (0xffffffffffff0000). This mapping is not enabled until
the architecture specific cpu_init() function is run, which causes problems
since some generic code is run before this point. In particular when
CONFIG_PRINTK_TIME is enabled, the boot cpu will trap on the access to
per-cpu memory at the first printk() call so the boot will fail without
the kernel printing anything to the console.
Fix this by allocating percpu memory for cpu0 in the kernel data section
and doing all initialization to enable percpu access in head.S before
calling any generic code.
Other cpus must take care not to access per-cpu variables too early, but
their code path from start_secondary() to cpu_init() is all in arch/ia64
Signed-off-by: Tony Luck <tony.luck@intel.com>
arch/ia64/kernel/vmlinux.lds is a generated file. Tell
git to ignore it.
Signed-off-by: Robin Holt <holt@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Recent kernels are not booting on some HP systems (though
it does boot on others). James and Willy reported the
problem. James did the bisection to find the commit
that caused the problem:
498c517047.
[IA64] pvops: paravirtualize ivt.S
Two instructions were wrongly paravirtualized such that
_FROM_ macro had been used where _TO_ was intended
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: "Wilcox, Matthew R" <matthew.r.wilcox@intel.com>
Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>
Signed-off-by: Tony Luck <tony.luck@intel.com>
After moving the the include files there were a few clean-ups:
1) Some files used #include <asm-ia64/xyz.h>, changed to <asm/xyz.h>
2) Some comments alerted maintainers to look at various header files to
make matching updates if certain code were to be changed. Updated these
comments to use the new include paths.
3) Some header files mentioned their own names in initial comments. Just
deleted these self references.
Signed-off-by: Tony Luck <tony.luck@intel.com>
This extends wait_task_inactive() with a new argument so it can be used in
a "soft" mode where it will check for the task changing state unexpectedly
and back off. There is no change to existing callers. This lays the
groundwork to allow robust, noninvasive tracing that can try to sample a
blocked thread but back off safely if it wakes up.
Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Reviewed-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently list of kretprobe instances are stored in kretprobe object (as
used_instances,free_instances) and in kretprobe hash table. We have one
global kretprobe lock to serialise the access to these lists. This causes
only one kretprobe handler to execute at a time. Hence affects system
performance, particularly on SMP systems and when return probe is set on
lot of functions (like on all systemcalls).
Solution proposed here gives fine-grain locks that performs better on SMP
system compared to present kretprobe implementation.
Solution:
1) Instead of having one global lock to protect kretprobe instances
present in kretprobe object and kretprobe hash table. We will have
two locks, one lock for protecting kretprobe hash table and another
lock for kretporbe object.
2) We hold lock present in kretprobe object while we modify kretprobe
instance in kretprobe object and we hold per-hash-list lock while
modifying kretprobe instances present in that hash list. To prevent
deadlock, we never grab a per-hash-list lock while holding a kretprobe
lock.
3) We can remove used_instances from struct kretprobe, as we can
track used instances of kretprobe instances using kretprobe hash
table.
Time duration for kernel compilation ("make -j 8") on a 8-way ppc64 system
with return probes set on all systemcalls looks like this.
cacheline non-cacheline Un-patched kernel
aligned patch aligned patch
===============================================================================
real 9m46.784s 9m54.412s 10m2.450s
user 40m5.715s 40m7.142s 40m4.273s
sys 2m57.754s 2m58.583s 3m17.430s
===========================================================
Time duration for kernel compilation ("make -j 8) on the same system, when
kernel is not probed.
=========================
real 9m26.389s
user 40m8.775s
sys 2m7.283s
=========================
Signed-off-by: Srinivasa DS <srinivasa@in.ibm.com>
Signed-off-by: Jim Keniston <jkenisto@us.ibm.com>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch introduces the new syscall pipe2 which is like pipe but it also
takes an additional parameter which takes a flag value. This patch implements
the handling of O_CLOEXEC for the flag. I did not add support for the new
syscall for the architectures which have a special sys_pipe implementation. I
think the maintainers of those archs have the chance to go with the unified
implementation but that's up to them.
The implementation introduces do_pipe_flags. I did that instead of changing
all callers of do_pipe because some of the callers are written in assembler.
I would probably screw up changing the assembly code. To avoid breaking code
do_pipe is now a small wrapper around do_pipe_flags. Once all callers are
changed over to do_pipe_flags the old do_pipe function can be removed.
The following test must be adjusted for architectures other than x86 and
x86-64 and in case the syscall numbers changed.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#include <fcntl.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/syscall.h>
#ifndef __NR_pipe2
# ifdef __x86_64__
# define __NR_pipe2 293
# elif defined __i386__
# define __NR_pipe2 331
# else
# error "need __NR_pipe2"
# endif
#endif
int
main (void)
{
int fd[2];
if (syscall (__NR_pipe2, fd, 0) != 0)
{
puts ("pipe2(0) failed");
return 1;
}
for (int i = 0; i < 2; ++i)
{
int coe = fcntl (fd[i], F_GETFD);
if (coe == -1)
{
puts ("fcntl failed");
return 1;
}
if (coe & FD_CLOEXEC)
{
printf ("pipe2(0) set close-on-exit for fd[%d]\n", i);
return 1;
}
}
close (fd[0]);
close (fd[1]);
if (syscall (__NR_pipe2, fd, O_CLOEXEC) != 0)
{
puts ("pipe2(O_CLOEXEC) failed");
return 1;
}
for (int i = 0; i < 2; ++i)
{
int coe = fcntl (fd[i], F_GETFD);
if (coe == -1)
{
puts ("fcntl failed");
return 1;
}
if ((coe & FD_CLOEXEC) == 0)
{
printf ("pipe2(O_CLOEXEC) does not set close-on-exit for fd[%d]\n", i);
return 1;
}
}
close (fd[0]);
close (fd[1]);
puts ("OK");
return 0;
}
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Signed-off-by: Ulrich Drepper <drepper@redhat.com>
Acked-by: Davide Libenzi <davidel@xmailserver.org>
Cc: Michael Kerrisk <mtk.manpages@googlemail.com>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This allow to dynamically generate attributes and share show/store
functions between attributes. Right now most attributes are generated
by special macros and lots of duplicated code. With the attribute
passed it's instead possible to attach some data to the attribute
and then use that in shared low level functions to do different things.
I need this for the dynamically generated bank attributes in the x86
machine check code, but it'll allow some further cleanups.
I converted all users in tree to the new show/store prototype. It's a single
huge patch to avoid unbisectable sections.
Runtime tested: x86-32, x86-64
Compiled only: ia64, powerpc
Not compile tested/only grep converted: sh, arm, avr32
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
acpi_map_lsapic tries to stuff a long into ia64_cpu_to_sapicid[],
which can only hold ints, so let's fix that.
We need to update the signature of acpi_map_cpu2node() too.
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
module_free() refers the first parameter before checking.
But it is called like below(in kernel/kprobes). The first parameter is always NULL.
This happens when many probe points(>1024) are set by kprobes.
I encountered this with using SystemTap. It can set many probes easily.
static int __kprobes collect_one_slot(struct kprobe_insn_page *kip, int idx)
{
...
if (kip->nused == 0) {
hlist_del(&kip->hlist);
if (hlist_empty(&kprobe_insn_pages)) {
...
} else {
module_free(NULL, kip->insns); //<<< 1st param always NULL
kfree(kip);
}
return 1;
}
return 0;
}
Signed-off-by: Akiyama, Nobuyuki <akiyama.nobuyuk@jp.fujitsu.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
When dprintk is enabled the following warnings are generated:
arch/ia64/kernel/cpufreq/acpi-cpufreq.c: In function 'processor_set_pstate':
arch/ia64/kernel/cpufreq/acpi-cpufreq.c:54: warning: format '%x' expects type 'unsigned int', but argumen
t 3 has type 's64'
arch/ia64/kernel/cpufreq/acpi-cpufreq.c: In function 'processor_get_pstate':
arch/ia64/kernel/cpufreq/acpi-cpufreq.c:76: warning: format '%x' expects type 'unsigned int', but argumen
t 2 has type 's64'
Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>
"idle=nomwait" disables the use of the MWAIT
instruction from both C1 (C1_FFH) and deeper (C2C3_FFH)
C-states.
When MWAIT is unavailable, the BIOS and OS generally
negotiate to use the HALT instruction for C1,
and use IO accesses for deeper C-states.
This option is useful for power and performance
comparisons, and also to work around BIOS bugs
where broken MWAIT support is advertised.
http://bugzilla.kernel.org/show_bug.cgi?id=10807http://bugzilla.kernel.org/show_bug.cgi?id=10914
Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Li Shaohua <shaohua.li@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
"idle=halt" limits the idle loop to using
the halt instruction. No MWAIT, no IO accesses,
no C-states deeper than C1.
If something is broken in the idle code,
"idle=halt" is a less severe workaround
than "idle=poll" which disables all power savings.
Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
