additional_cpus=<x> parameter is dangerous and broken: for example
if we boot additional_cpus=-2 on a stock dual-core system it will
crash the box on bootup.
So reduce the maze of code a bit by removingthe user-configurability
angle.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
x86: allow number of additional hotplug CPUs to be set at compile time, V2
The default number of additional CPU IDs for hotplugging is determined
by asking ACPI or mptables how many "disabled" CPUs there are in the
system, but many systems get this wrong so that e.g. a uniprocessor
machine gets an extra CPU allocated and never switches to single CPU
mode.
And sometimes CPU hotplugging is enabled only for suspend/hibernate
anyway, so the additional CPU IDs are not wanted. Allow the number
to be set to zero at compile time.
Also, force the number of extra CPUs to zero if hotplugging is disabled
which allows removing some conditional code.
Tested on uniprocessor x86_64 that ACPI claims has a disabled processor,
with CPU hotplugging configured.
("After" has the number of additional CPUs set to 0)
Before: NR_CPUS: 512, nr_cpu_ids: 2, nr_node_ids 1
After: NR_CPUS: 512, nr_cpu_ids: 1, nr_node_ids 1
[Changed the name of the option and the prompt according to Ingo's
suggestion.]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Commit 4a701737 ("x86: move prefill_possible_map calling early, fix")
is the wrong fix: prefill_possible_map() needs to be available
even when CONFIG_HOTPLUG_CPU is not set. A followon patch will do that.
Fix this correctly by making prefill_possible_map() available even when
CONFIG_HOTPLUG_CPU is not set. The function is needed so that
the number of possible CPUs can be determined.
Tested on uniprocessor machine with CPU hotplug disabled.
From boot log:
Before: NR_CPUS: 512, nr_cpu_ids: 512, nr_node_ids 1
After: NR_CPUS: 512, nr_cpu_ids: 1, nr_node_ids 1
Signed-off-by: Chuck Ebbert <cebbert@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
We should check if we have ESR register before reading from it.
Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: "Maciej W. Rozycki" <macro@linux-mips.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Secondary cpus start with local interrupts disabled.
start_secondary() first initializes the new cpu, then it enables the
local interrupts. (although interrupts are enabled within smp_callin()
as well).
Right now, the local interrupts are enabled as a side effect of calling
ipi_call_lock_irq().
The attached patch clarifies when local interrupts are enabled.
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'x86-v28-for-linus-phase4-D' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (186 commits)
x86, debug: print more information about unknown CPUs
x86 setup: handle more than 8 CPU flag words
x86: cpuid, fix typo
x86: move transmeta cap read to early_init_transmeta()
x86: identify_cpu_without_cpuid v2
x86: extended "flags" to show virtualization HW feature in /proc/cpuinfo
x86: move VMX MSRs to msr-index.h
x86: centaur_64.c remove duplicated setting of CONSTANT_TSC
x86: intel.c put workaround for old cpus together
x86: let intel 64-bit use intel.c
x86: make intel_64.c the same as intel.c
x86: make intel.c have 64-bit support code
x86: little clean up of intel.c/intel_64.c
x86: make 64 bit to use amd.c
x86: make amd_64 have 32 bit code
x86: make amd.c have 64bit support code
x86: merge header in amd_64.c
x86: add srat_detect_node for amd64
x86: remove duplicated force_mwait
x86: cpu make amd.c more like amd_64.c v2
...
* 'sched-v28-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (38 commits)
sched debug: add name to sched_domain sysctl entries
sched: sync wakeups vs avg_overlap
sched: remove redundant code in cpu_cgroup_create()
sched_rt.c: resch needed in rt_rq_enqueue() for the root rt_rq
cpusets: scan_for_empty_cpusets(), cpuset doesn't seem to be so const
sched: minor optimizations in wake_affine and select_task_rq_fair
sched: maintain only task entities in cfs_rq->tasks list
sched: fixup buddy selection
sched: more sanity checks on the bandwidth settings
sched: add some comments to the bandwidth code
sched: fixlet for group load balance
sched: rework wakeup preemption
CFS scheduler: documentation about scheduling policies
sched: clarify ifdef tangle
sched: fix list traversal to use _rcu variant
sched: turn off WAKEUP_OVERLAP
sched: wakeup preempt when small overlap
kernel/cpu.c: create a CPU_STARTING cpu_chain notifier
kernel/cpu.c: Move the CPU_DYING notifiers
sched: fix __load_balance_iterator() for cfq with only one task
...
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>
It allows paravirt implementations of cpu_disable to share the
cpu_disable_common code, without having to take on board APIC
writes, which may not be appropriate.
Signed-off-by: Alex Nixon <alex.nixon@citrix.com>
Acked-by: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Add the new play_dead into smpboot.c, as it fits more cleanly in there
alongside other CONFIG_HOTPLUG functions.
Separate out the common code into its own function.
Signed-off-by: Alex Nixon <alex.nixon@citrix.com>
Acked-by: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
WARNING: vmlinux.o(.cpuinit.text+0x3cc4): Section mismatch in reference from the function uv_cpu_init() to the function .init.text:uv_system_init()
The function __cpuinit uv_cpu_init() references
a function __init uv_system_init().
If uv_system_init is only used by uv_cpu_init then
annotate uv_system_init with a matching annotation.
uv_system_init was ment to be called only once, so do it from codepath
(native_smp_prepare_cpus) which is called once, right before activation
of other cpus (smp_init).
Note: old code relied on uv_node_to_blade being initialized to 0,
but it'a not initialized from anywhere.
Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com>
Acked-by: Jack Steiner <steiner@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Take out part of get_local_pda referencing __init function (free_bootmem)
to new (static) function marked as __ref. It's safe to do because free_bootmem
is called before __init sections are dropped.
WARNING: vmlinux.o(.cpuinit.text+0x3cd7): Section mismatch in reference from the function get_local_pda() to the function .init.text:free_bootmem()
The function __cpuinit get_local_pda() references
a function __init free_bootmem().
If free_bootmem is only used by get_local_pda then
annotate free_bootmem with a matching annotation.
Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com>
Cc: Mike Travis <travis@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
prefill_possible_map() is defined inside CONFIG_HOTPLUG_CPU,
so the nesting CONFIG_HOTPLUG_CPU is just redundant.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
clear bits for cpu nr > 8.
This allows us to boot the full range of possible CPUs that the
supported APIC model will allow. Previously we'd hang or boot up
with less than 8 CPUs.
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Tested-by: Jeff Chua <jeff.chua.linux@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
For some reason we had two parsers registered for maxcpus=. One in init/main.c
and another in arch/x86/smpboot.c. So I nuked the one in arch/x86.
Also 64-bit kernels used to handle maxcpus= as documented in
Documentation/cpu-hotplug.txt. CPUs with 'id > maxcpus' are initialized
but not booted. 32-bit version for some reason ignored them even though
all the infrastructure for booting them later is there.
In the current mainline both 64 and 32 bit versions are broken.
This patch restores the correct behaviour. I've tested x86_64 version on
4- and 8- way Core2 and 2-way Opteron based machines. Various config
combinations SMP, !SMP, CPU_HOTPLUG, !CPU_HOTPLUG.
Booted with maxcpus=1 and maxcpus=4, etc. Everything is working as expected.
So far we've received two reports from different people confirming that 32-bit
version also works fine, both on dual core laptops and 16way server machines.
[v2: This version fixes visws breakage pointed out by Ingo.]
Signed-off-by: Max Krasnyansky <maxk@qualcomm.com>
Cc: lizf@cn.fujitsu.com
Cc: jeff.chua.linux@gmail.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Jeff Chua reported that booting a !bigsmp kernel on a 16-way box
hangs silently.
this is a long-standing issue, smp start AP cpu could check the
apic id >=8 etc before trying to start it.
achieve this by moving the def_to_bigsmp check later and skip the
apicid id > 8
[ mingo@elte.hu: clean up the message that is printed. ]
Reported-by: "Jeff Chua" <jeff.chua.linux@gmail.com>
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
arch/x86/kernel/setup.c | 6 ------
arch/x86/kernel/smpboot.c | 10 ++++++++++
2 files changed, 10 insertions(+), 6 deletions(-)
Having cpu_online_map change during assign_irq_vector can result
in some really nasty and weird things happening. The one that
bit me last time was accessing non existent per cpu memory for non
existent cpus.
This locking was removed in a sloppy x86_64 and x86_32 merge patch.
Guys can we please try and avoid subtly breaking x86 when we are
merging files together?
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
* 'cpus4096-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (31 commits)
NR_CPUS: Replace NR_CPUS in speedstep-centrino.c
cpumask: Provide a generic set of CPUMASK_ALLOC macros, FIXUP
NR_CPUS: Replace NR_CPUS in cpufreq userspace routines
NR_CPUS: Replace per_cpu(..., smp_processor_id()) with __get_cpu_var
NR_CPUS: Replace NR_CPUS in arch/x86/kernel/genapic_flat_64.c
NR_CPUS: Replace NR_CPUS in arch/x86/kernel/genx2apic_uv_x.c
NR_CPUS: Replace NR_CPUS in arch/x86/kernel/cpu/proc.c
NR_CPUS: Replace NR_CPUS in arch/x86/kernel/cpu/mcheck/mce_64.c
cpumask: Optimize cpumask_of_cpu in lib/smp_processor_id.c, fix
cpumask: Use optimized CPUMASK_ALLOC macros in the centrino_target
cpumask: Provide a generic set of CPUMASK_ALLOC macros
cpumask: Optimize cpumask_of_cpu in lib/smp_processor_id.c
cpumask: Optimize cpumask_of_cpu in kernel/time/tick-common.c
cpumask: Optimize cpumask_of_cpu in drivers/misc/sgi-xp/xpc_main.c
cpumask: Optimize cpumask_of_cpu in arch/x86/kernel/ldt.c
cpumask: Optimize cpumask_of_cpu in arch/x86/kernel/io_apic_64.c
cpumask: Replace cpumask_of_cpu with cpumask_of_cpu_ptr
Revert "cpumask: introduce new APIs"
cpumask: make for_each_cpu_mask a bit smaller
net: Pass reference to cpumask variable in net/sunrpc/svc.c
...
Fix up trivial conflicts in drivers/cpufreq/cpufreq.c manually
There are a couple of places where (P)Dprintk is used which is an old
compile time enabled printk wrapper. Convert it to the generic
pr_debug().
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Use alternatives to select the workaround for the 11AP Pentium erratum
for the affected steppings on the fly rather than build time. Remove the
X86_GOOD_APIC configuration option and replace all the calls to
apic_write_around() with plain apic_write(), protecting accesses to the
ESR as appropriate due to the 3AP Pentium erratum. Remove
apic_read_around() and all its invocations altogether as not needed.
Remove apic_write_atomic() and all its implementing backends. The use of
ASM_OUTPUT2() is not strictly needed for input constraints, but I have
used it for readability's sake.
I had the feeling no one else was brave enough to do it, so I went ahead
and here it is. Verified by checking the generated assembly and tested
with both a 32-bit and a 64-bit configuration, also with the 11AP
"feature" forced on and verified with gdb on /proc/kcore to work as
expected (as an 11AP machines are quite hard to get hands on these days).
Some script complained about the use of "volatile", but apic_write() needs
it for the same reason and is effectively a replacement for writel(), so I
have disregarded it.
I am not sure what the policy wrt defconfig files is, they are generated
and there is risk of a conflict resulting from an unrelated change, so I
have left changes to them out. The option will get removed from them at
the next run.
Some testing with machines other than mine will be needed to avoid some
stupid mistake, but despite its volume, the change is not really that
intrusive, so I am fairly confident that because it works for me, it will
everywhere.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This allows Xen's xen_cpu_up() to allocate a pda for the new CPU.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
also remove GET_APIC_ID when read_apic_id is used.
need to apply after
[PATCH] x86: mach_apicdef.h need to include before smp.h
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
x2apic support. Interrupt-remapping must be enabled before enabling x2apic,
this is needed to ensure that IO interrupts continue to work properly after the
cpu mode is changed to x2apic(which uses 32bit extended physical/cluster
apic id).
On systems where apicid's are > 255, BIOS can handover the control to OS in
x2apic mode. Or if the OS handover was in legacy xapic mode, check
if it is capable of x2apic mode. And if we succeed in enabling
Interrupt-remapping, then we can enable x2apic mode in the CPU.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: akpm@linux-foundation.org
Cc: arjan@linux.intel.com
Cc: andi@firstfloor.org
Cc: ebiederm@xmission.com
Cc: jbarnes@virtuousgeek.org
Cc: steiner@sgi.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Introduce basic apic operations which handle the apic programming. This
will be used later to introduce another specific operations for x2apic.
For the perfomance critial accesses like IPI's, EOI etc, we use the
native operations as they are already referenced by different
indirections like genapic, irq_chip etc.
64bit Paravirt ops can also define their apic operations accordingly.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: akpm@linux-foundation.org
Cc: arjan@linux.intel.com
Cc: andi@firstfloor.org
Cc: ebiederm@xmission.com
Cc: jbarnes@virtuousgeek.org
Cc: steiner@sgi.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
arch/x86/kernel/smpboot.c: In function 'do_boot_cpu':
arch/x86/kernel/smpboot.c:943: warning: label 'restore_state' defined but not used
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
call it right after we are done with MADT/mptable handling, instead of
doing that in setup_per_cpu_areas() later on...
this way for_possible_cpu() can be used early.
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
There is no need to keep NMI_DISABLED definition and use it
for nmi_watchdog by default. Here is the point why:
- IO-APIC and APIC chips are programmed for nmi_watchdog support at very
early stage of kernel booting and not having nmi_watchdog specified as
boot option lead only to nmi_watchdog becomes to NMI_NONE anyway
- enable nmi_watchdog thru /proc/sys/kernel/nmi if it was not specified at
boot is not possible too (even having this sysfs entry)
Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: macro@linux-mips.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
there's no particular reason to do load_sp0 in different
places for i386 and x86_64. They should all be in cpu_init.
Right now, cpu_init itself is not integrated, but with this patch,
the code becomes closer to each other, making in easier to integrate
when the time comes.
Furthermore, although doing it in do_boot_cpu for x86_64 is fine, since it's
only a copy, load_sp0 should be executed in the cpu it refers to anyway.
Signed-off-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
