Setting the interrupt affinity of a single interrupt to multiple CPUs has a
dubious value.
1) This only works on machines where the APIC uses logical destination
mode. If the APIC uses physical destination mode then it is already
restricted to a single CPU
2) Experiments have shown, that the benefit of multi CPU affinity is close
to zero and in some test even worse than setting the affinity to a
single CPU.
The reason for this is that the delivery targets the APIC with the
lowest ID first and only if that APIC is busy (servicing an interrupt,
i.e. ISR is not empty) it hands it over to the next APIC. In the
conducted tests the vast majority of interrupts ends up on the APIC
with the lowest ID anyway, so there is no natural spreading of the
interrupts possible.
Supporting multi CPU affinities adds a lot of complexity to the code, which
can turn the allocation search into a worst case of
nr_vectors * nr_online_cpus * nr_bits_in_target_mask
As a first step disable it by restricting the vector search to a single
CPU.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Juergen Gross <jgross@suse.com>
Tested-by: Yu Chen <yu.c.chen@intel.com>
Acked-by: Juergen Gross <jgross@suse.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Alok Kataria <akataria@vmware.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Rui Zhang <rui.zhang@intel.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Len Brown <lenb@kernel.org>
Link: https://lkml.kernel.org/r/20170913213154.228824430@linutronix.de
A cold or warm boot through BIOS sets the APIC in default interrupt
delivery mode. A dump-capture kernel will not go through a BIOS reset and
leave the interrupt delivery mode in the state which was active on the
crashed kernel, but the dump kernel startup code assumes default delivery
mode which can result in interrupt delivery/handling to fail.
To solve this problem, it's required to set up the final interrupt delivery
mode as soon as possible. As IOAPIC setup needs the timer initialized for
verifying the timer interrupt delivery mode, the earliest point is right
after timer setup in late_time_init().
That results in the following init order:
1) Set up the legacy timer, if applicable on the platform
2) Set up APIC/IOAPIC which includes the verification of the legacy timer
interrupt delivery.
3) TSC calibration
4) Local APIC timer setup
Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: yinghai@kernel.org
Cc: bhe@redhat.com
Link: https://lkml.kernel.org/r/1505293975-26005-12-git-send-email-douly.fnst@cn.fujitsu.com
timer_irq_works() is used to detects the timer IRQs. It calls mdelay(10) to
delay ten ticks and check whether the timer IRQ work or not.
mdelay() depends on the loops_per_jiffy which is set up in
calibrate_delay(), but the delay calibration depends on a working timer
interrupt, which causes a chicken and egg problem.
The correct solution is to set up the interrupt mode and making sure that
the timer interrupt is delivered correctly before invoking calibrate_delay().
That means that mdelay() cannot be used in timer_irq_works().
Provide helper functions to make a rough delay estimate which is good enough
to prove that the timer interrupt is working. Either use TSC or a simple
delay loop and assume that 4GHz is the maximum CPU frequency to base the
delay calculation on.
Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: yinghai@kernel.org
Cc: bhe@redhat.com
Link: https://lkml.kernel.org/r/1505293975-26005-9-git-send-email-douly.fnst@cn.fujitsu.com
On a SMP-capable system, the kernel enables and sets up the APIC interrupt
delivery mode in native_smp_prepare_cpus(). The decision how to setup the
APIC is intermingled with the decision of setting up SMP or not.
Split the initialization of the APIC interrupt mode independent from other
decisions and have a separate apic_intr_mode_init() function for it.
The invocation time stays the same for now.
Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: yinghai@kernel.org
Cc: bhe@redhat.com
Link: https://lkml.kernel.org/r/1505293975-26005-6-git-send-email-douly.fnst@cn.fujitsu.com
There are three places which initialize the interrupt delivery modes:
1) init_bsp_APIC() which is called early might setup the through-local-APIC
virtual wire mode on non SMP systems.
2) In an SMP-capable system, native_smp_prepare_cpus() tries to switch to
symmetric I/O model.
3) In UP system with UP_LATE_INIT=y, the local APIC and I/O APIC are set up
in smp_init().
There is no technical reason to make these initializations at random places
and run the kernel with the potentially wrong mode through the early boot
stage, but it has a problematic side effect: The late switch to symmetric
I/O mode causes dump-capture kernel to hang when the kernel command line
option 'notsc' is active.
Provide a new function to unify that three positions. Preparatory patch to
initialize an interrupt mode directly.
Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: yinghai@kernel.org
Cc: bhe@redhat.com
Link: https://lkml.kernel.org/r/1505293975-26005-3-git-send-email-douly.fnst@cn.fujitsu.com
There are quite some switches which are used to determine the final
interrupt delivery mode, as shown below:
1) Kconfig: CONFIG_X86_64; CONFIG_X86_LOCAL_APIC; CONFIG_x86_IO_APIC
2) Command line options: disable_apic; skip_ioapic_setup
3) CPU Capability: boot_cpu_has(X86_FEATURE_APIC)
4) MP table: smp_found_config
5) ACPI: acpi_lapic; acpi_ioapic; nr_ioapic
These switches are disordered and scattered and there are also some
dependencies between them. These make the code difficult to maintain and
read.
Construct a selector to unify them into a single function, then, Use this
selector to get an interrupt delivery mode directly.
Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: yinghai@kernel.org
Cc: bhe@redhat.com
Link: https://lkml.kernel.org/r/1505293975-26005-2-git-send-email-douly.fnst@cn.fujitsu.com
Pull x86 fixes from Ingo Molnar:
"Two fixes: dead code removal, plus a SME memory encryption fix on
32-bit kernels that crashed Xen guests"
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/cpu: Remove unused and undefined __generic_processor_info() declaration
x86/mm: Make the SME mask a u64
First, number of CPUs can't be negative number.
Second, different signnnedness leads to suboptimal code in the following
cases:
1)
kmalloc(nr_cpu_ids * sizeof(X));
"int" has to be sign extended to size_t.
2)
while (loff_t *pos < nr_cpu_ids)
MOVSXD is 1 byte longed than the same MOV.
Other cases exist as well. Basically compiler is told that nr_cpu_ids
can't be negative which can't be deduced if it is "int".
Code savings on allyesconfig kernel: -3KB
add/remove: 0/0 grow/shrink: 25/264 up/down: 261/-3631 (-3370)
function old new delta
coretemp_cpu_online 450 512 +62
rcu_init_one 1234 1272 +38
pci_device_probe 374 399 +25
...
pgdat_reclaimable_pages 628 556 -72
select_fallback_rq 446 369 -77
task_numa_find_cpu 1923 1807 -116
Link: http://lkml.kernel.org/r/20170819114959.GA30580@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When booting 4.13 on a VirtualBox VM on a Skylake host the following
error shows up in the logs:
[ 0.000000] [Firmware Bug]: TSC_DEADLINE disabled due to Errata;
please update microcode to version: 0xb2 (or later)
This is caused by apic_check_deadline_errata() only checking CPU model
and not the X86_FEATURE_TSC_DEADLINE_TIMER flag (which VirtualBox does
NOT export to the guest), combined with VirtualBox not exporting the
micro-code version to the guest.
This commit adds a check for X86_FEATURE_TSC_DEADLINE_TIMER to
apic_check_deadline_errata(), silencing this error on VirtualBox VMs.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Frank Mehnert <frank.mehnert@oracle.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Thayer <michael.thayer@oracle.com>
Cc: Michal Necasek <michal.necasek@oracle.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Fixes: bd9240a18e ("x86/apic: Add TSC_DEADLINE quirk due to errata")
Link: http://lkml.kernel.org/r/20170830105811.27539-1-hdegoede@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
One of the rarely executed code pathes in check_timer() calls
unmask_ioapic_irq() passing irq_get_chip_data(0) as argument.
That's wrong as unmask_ioapic_irq() expects a pointer to the irq data of
interrupt 0. irq_get_chip_data(0) returns NULL, so the following
dereference in unmask_ioapic_irq() causes a kernel panic.
The issue went unnoticed in the first place because irq_get_chip_data()
returns a void pointer so the compiler cannot do a type check on the
argument. The code path was added for machines with broken configuration,
but it seems that those machines are either not running current kernels or
simply do not longer exist.
Hand in irq_get_irq_data(0) as argument which provides the correct data.
[ tglx: Rewrote changelog ]
Fixes: 4467715a44 ("x86/irq: Move irq_cfg.irq_2_pin into io_apic.c")
Signed-off-by: Seunghun Han <kkamagui@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1500369644-45767-1-git-send-email-kkamagui@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Split SOFTLOCKUP_DETECTOR from LOCKUP_DETECTOR, and split
HARDLOCKUP_DETECTOR_PERF from HARDLOCKUP_DETECTOR.
LOCKUP_DETECTOR implies the general boot, sysctl, and programming
interfaces for the lockup detectors.
An architecture that wants to use a hard lockup detector must define
HAVE_HARDLOCKUP_DETECTOR_PERF or HAVE_HARDLOCKUP_DETECTOR_ARCH.
Alternatively an arch can define HAVE_NMI_WATCHDOG, which provides the
minimum arch_touch_nmi_watchdog, and it otherwise does its own thing and
does not implement the LOCKUP_DETECTOR interfaces.
sparc is unusual in that it has started to implement some of the
interfaces, but not fully yet. It should probably be converted to a full
HAVE_HARDLOCKUP_DETECTOR_ARCH.
[npiggin@gmail.com: fix]
Link: http://lkml.kernel.org/r/20170617223522.66c0ad88@roar.ozlabs.ibm.com
Link: http://lkml.kernel.org/r/20170616065715.18390-4-npiggin@gmail.com
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Don Zickus <dzickus@redhat.com>
Reviewed-by: Babu Moger <babu.moger@oracle.com>
Tested-by: Babu Moger <babu.moger@oracle.com> [sparc]
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull x86 timers updates from Thomas Gleixner:
"This update contains:
- The solution for the TSC deadline timer borkage, which is caused by
a hardware problem in the TSC_ADJUST/TSC_DEADLINE_TIMER logic.
The problem is documented now and fixed with a microcode update, so
we can remove the workaround and just check for the microcode version.
If the microcode is not up to date, then the TSC deadline timer is
disabled. If the borkage is fixed by the proper microcode version,
then the deadline timer can be used. In both cases the restrictions
to the range of the TSC_ADJUST value, which were added as
workarounds, are removed.
- A few simple fixes and updates to the timer related x86 code"
* 'x86-timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/tsc: Call check_system_tsc_reliable() before unsynchronized_tsc()
x86/hpet: Do not use smp_processor_id() in preemptible code
x86/time: Make setup_default_timer_irq() static
x86/tsc: Remove the TSC_ADJUST clamp
x86/apic: Add TSC_DEADLINE quirk due to errata
x86/apic: Change the lapic name in deadline mode
Pull irq updates from Thomas Gleixner:
"The irq department delivers:
- Expand the generic infrastructure handling the irq migration on CPU
hotplug and convert X86 over to it. (Thomas Gleixner)
Aside of consolidating code this is a preparatory change for:
- Finalizing the affinity management for multi-queue devices. The
main change here is to shut down interrupts which are affine to a
outgoing CPU and reenabling them when the CPU comes online again.
That avoids moving interrupts pointlessly around and breaking and
reestablishing affinities for no value. (Christoph Hellwig)
Note: This contains also the BLOCK-MQ and NVME changes which depend
on the rework of the irq core infrastructure. Jens acked them and
agreed that they should go with the irq changes.
- Consolidation of irq domain code (Marc Zyngier)
- State tracking consolidation in the core code (Jeffy Chen)
- Add debug infrastructure for hierarchical irq domains (Thomas
Gleixner)
- Infrastructure enhancement for managing generic interrupt chips via
devmem (Bartosz Golaszewski)
- Constification work all over the place (Tobias Klauser)
- Two new interrupt controller drivers for MVEBU (Thomas Petazzoni)
- The usual set of fixes, updates and enhancements all over the
place"
* 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (112 commits)
irqchip/or1k-pic: Fix interrupt acknowledgement
irqchip/irq-mvebu-gicp: Allocate enough memory for spi_bitmap
irqchip/gic-v3: Fix out-of-bound access in gic_set_affinity
nvme: Allocate queues for all possible CPUs
blk-mq: Create hctx for each present CPU
blk-mq: Include all present CPUs in the default queue mapping
genirq: Avoid unnecessary low level irq function calls
genirq: Set irq masked state when initializing irq_desc
genirq/timings: Add infrastructure for estimating the next interrupt arrival time
genirq/timings: Add infrastructure to track the interrupt timings
genirq/debugfs: Remove pointless NULL pointer check
irqchip/gic-v3-its: Don't assume GICv3 hardware supports 16bit INTID
irqchip/gic-v3-its: Add ACPI NUMA node mapping
irqchip/gic-v3-its-platform-msi: Make of_device_ids const
irqchip/gic-v3-its: Make of_device_ids const
irqchip/irq-mvebu-icu: Add new driver for Marvell ICU
irqchip/irq-mvebu-gicp: Add new driver for Marvell GICP
dt-bindings/interrupt-controller: Add DT binding for the Marvell ICU
genirq/irqdomain: Remove auto-recursive hierarchy support
irqchip/MSI: Use irq_domain_update_bus_token instead of an open coded access
...
