The following commit:
a9bcaa02a5 ("x86/smpboot: Remove SIPI delays from cpu_up()")
Caused some Intel Core2 processors to time-out when bringing up CPU #1,
resulting in the missing of that CPU after bootup.
That patch reduced the SIPI delays from udelay() 300, 200 to udelay() 0,
0 on modern processors.
Several Intel(R) Core(TM)2 systems failed to bring up CPU #1 10/10 times
after that change.
Increasing either of the SIPI delays to udelay(1) results in
success. So here we increase both to udelay(10). While this may
be 20x slower than the absolute minimum, it is still 20x to 30x
faster than the original code.
Tested-by: Donald Parsons <dparsons@brightdsl.net>
Tested-by: Shane <shrybman@teksavvy.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dparsons@brightdsl.net
Cc: shrybman@teksavvy.com
Link: http://lkml.kernel.org/r/6dd554ee8945984d85aafb2ad35793174d068af0.1444968087.git.len.brown@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
For legacy machines cpu_init_udelay defaults to 10,000.
For modern machines it is set to 0.
The user should be able to set cpu_init_udelay to
any value on the cmdline, including 10,000.
Before this patch, that was seen as "unchanged from default"
and thus on a modern machine, the user request was ignored
and the delay was set to 0.
Signed-off-by: Len Brown <len.brown@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dparsons@brightdsl.net
Cc: shrybman@teksavvy.com
Link: http://lkml.kernel.org/r/de363cdbbcfcca1d22569683f7eb9873e0177251.1444968087.git.len.brown@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull x86 init code fixlet from Ingo Molnar:
"A single change: fix obsolete init code annotations"
* 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86: Drop bogus __ref / __refdata annotations
Both the per-APIC flag ".wait_for_init_deassert",
and the global atomic_t "init_deasserted"
are dead code -- remove them.
For all APIC types, "wait_for_master()"
prevents an AP from proceeding until the BSP has set
cpu_callout_mask, making "init_deasserted" {unnecessary}:
BSP: <de-assert INIT>
...
BSP: {set init_deasserted}
AP: wait_for_master()
set cpu_initialized_mask
wait for cpu_callout_mask
BSP: test cpu_initialized_mask
BSP: set cpu_callout_mask
AP: test cpu_callout_mask
AP: {wait for init_deasserted}
...
AP: <touch APIC>
Deleting the {dead code} above is necessary to enable
some parallelism in a future patch.
Signed-off-by: Len Brown <len.brown@intel.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Jan H. Schönherr <jschoenh@amazon.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Zhu Guihua <zhugh.fnst@cn.fujitsu.com>
Link: http://lkml.kernel.org/r/de4b3a9bab894735e285870b5296da25ee6a8a5a.1439739165.git.len.brown@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
MPS 1.4 example code shows the following required delays during processor
on-lining:
INIT
udelay(10,000)
SIPI
udelay(200)
SIPI
udelay(200) /* Linux actually implements this as udelay(300) */
Linux skips the udelay(10,000) on modern processors.
This patch removes the udelay(200) after each SIPI
on those same processors.
All three legacy delays can be restored by the cmdline
"cpu_init_udelay=10000".
As measured by analyze_suspend.py, this patch speeds
processor resume time on my desktop from 2.4ms to 1.8ms, per AP.
Signed-off-by: Len Brown <len.brown@intel.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Jan H. Schönherr <jschoenh@amazon.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Zhu Guihua <zhugh.fnst@cn.fujitsu.com>
Link: http://lkml.kernel.org/r/a5dfdbc8fbfdd813784da204aad5677fe459ac37.1439739165.git.len.brown@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
After the BSP sends INIT/SIPI/SIP to the AP and sees the AP
in the cpu_initialized_map, it sets the AP loose via the
cpu_callout_map, and waits for it via the cpu_callin_map.
The BSP polls the cpu_callin_map with a udelay(100)
and a schedule() in each iteration.
The udelay(100) adds no value.
For example, on my 4-CPU dekstop, the AP finishes
cpu_callin() in under 70 usec and sets the cpu_callin_mask.
The BSP, however, doesn't see that setting until over 30 usec
later, because it was still running its udelay(100)
when the AP finished.
Deleting the udelay(100) in the cpu_callin_mask polling loop,
saves from 0 to 100 usec per Application Processor.
Signed-off-by: Len Brown <len.brown@intel.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Jan H. Schönherr <jschoenh@amazon.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Zhu Guihua <zhugh.fnst@cn.fujitsu.com>
Link: http://lkml.kernel.org/r/0aade12eabeb89a688c929fe80856eaea0544bb7.1439739165.git.len.brown@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
After the BSP sends the APIC INIT/SIPI/SIPI to the AP,
it waits for the AP to come up and indicate that it is alive
by setting its own bit in the cpu_initialized_mask.
Linux polls for up to 10 seconds for this to happen.
Each polling loop has a udelay(100) and a call to schedule().
The udelay(100) adds no value.
For example, on my desktop, the BSP waits for the
other 3 CPUs to come on line at boot for 305, 404, 405 usec.
For resume from S3, it waits 317, 404, 405 usec.
But when the udelay(100) is removed, the BSP waits
305, 310, 306 for boot, and 305, 307, 306 for resume.
So for both boot and resume, removing the udelay(100)
speeds online by about 100us in 2 of 3 cases.
Signed-off-by: Len Brown <len.brown@intel.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Jan H. Schönherr <jschoenh@amazon.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Zhu Guihua <zhugh.fnst@cn.fujitsu.com>
Link: http://lkml.kernel.org/r/33ef746c67d2489cad0a9b1958cf71167232ff2b.1439739165.git.len.brown@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The __ref / __refdata annotations used to be needed because of
referencing functions / variables annotated __cpuinit /
__cpuinitdata.
But those annotations vanished during the development of v3.11.
Therefore most of the __ref / __refdata annotations are not needed
anymore. As they may hide legitimate sections mismatches, we
better get rid of them.
Signed-off-by: Mathias Krause <minipli@googlemail.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1437409973-8927-1-git-send-email-minipli@googlemail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Boris reported that the sparse_irq protection around __cpu_up() in the
generic code causes a regression on Xen. Xen allocates interrupts and
some more in the xen_cpu_up() function, so it deadlocks on the
sparse_irq_lock.
There is no simple fix for this and we really should have the
protection for all architectures, but for now the only solution is to
move it to x86 where actual wreckage due to the lack of protection has
been observed.
Reported-and-tested-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Fixes: a899418167 'hotplug: Prevent alloc/free of irq descriptors during cpu up/down'
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: xiao jin <jin.xiao@intel.com>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Yanmin Zhang <yanmin_zhang@linux.intel.com>
Cc: xen-devel <xen-devel@lists.xenproject.org>
Jin debugged a nasty cpu hotplug race which results in leaking a irq
vector on the newly hotplugged cpu.
cpu N cpu M
native_cpu_up device_shutdown
do_boot_cpu free_msi_irqs
start_secondary arch_teardown_msi_irqs
smp_callin default_teardown_msi_irqs
setup_vector_irq arch_teardown_msi_irq
__setup_vector_irq native_teardown_msi_irq
lock(vector_lock) destroy_irq
install vectors
unlock(vector_lock)
lock(vector_lock)
---> __clear_irq_vector
unlock(vector_lock)
lock(vector_lock)
set_cpu_online
unlock(vector_lock)
This leaves the irq vector(s) which are torn down on CPU M stale in
the vector array of CPU N, because CPU M does not see CPU N online
yet. There is a similar issue with concurrent newly setup interrupts.
The alloc/free protection of irq descriptors does not prevent the
above race, because it merily prevents interrupt descriptors from
going away or changing concurrently.
Prevent this by moving the call to setup_vector_irq() into the
vector_lock held region which protects set_cpu_online():
cpu N cpu M
native_cpu_up device_shutdown
do_boot_cpu free_msi_irqs
start_secondary arch_teardown_msi_irqs
smp_callin default_teardown_msi_irqs
lock(vector_lock) arch_teardown_msi_irq
setup_vector_irq()
__setup_vector_irq native_teardown_msi_irq
install vectors destroy_irq
set_cpu_online
unlock(vector_lock)
lock(vector_lock)
__clear_irq_vector
unlock(vector_lock)
So cpu M either sees the cpu N online before clearing the vector or
cpu N installs the vectors after cpu M has cleared it.
Reported-by: xiao jin <jin.xiao@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Yanmin Zhang <yanmin_zhang@linux.intel.com>
Link: http://lkml.kernel.org/r/20150705171102.141898931@linutronix.de
As we alloc pages with GFP_KERNEL in init_espfix_ap() which is
called before we enable local irqs, so the lockdep sub-system
would (correctly) trigger a warning about the potentially
blocking API.
So we allocate them on the boot CPU side when the secondary CPU is
brought up by the boot CPU, and hand them over to the secondary
CPU.
And we use alloc_pages_node() with the secondary CPU's node, to
make sure the espfix stack is NUMA-local to the CPU that is
going to use it.
Signed-off-by: Zhu Guihua <zhugh.fnst@cn.fujitsu.com>
Cc: <bp@alien8.de>
Cc: <luto@amacapital.net>
Cc: <luto@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/c97add2670e9abebb90095369f0cfc172373ac94.1435824469.git.zhugh.fnst@cn.fujitsu.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Add a CPU index parameter to init_espfix_ap(), so that the
parameter could be propagated to the function for espfix
page allocation.
Signed-off-by: Zhu Guihua <zhugh.fnst@cn.fujitsu.com>
Cc: <bp@alien8.de>
Cc: <luto@amacapital.net>
Cc: <luto@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/cde3fcf1b3211f3f03feb1a995bce3fee850f0fc.1435824469.git.zhugh.fnst@cn.fujitsu.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull x86 core updates from Ingo Molnar:
"There were so many changes in the x86/asm, x86/apic and x86/mm topics
in this cycle that the topical separation of -tip broke down somewhat -
so the result is a more traditional architecture pull request,
collected into the 'x86/core' topic.
The topics were still maintained separately as far as possible, so
bisectability and conceptual separation should still be pretty good -
but there were a handful of merge points to avoid excessive
dependencies (and conflicts) that would have been poorly tested in the
end.
The next cycle will hopefully be much more quiet (or at least will
have fewer dependencies).
The main changes in this cycle were:
* x86/apic changes, with related IRQ core changes: (Jiang Liu, Thomas
Gleixner)
- This is the second and most intrusive part of changes to the x86
interrupt handling - full conversion to hierarchical interrupt
domains:
[IOAPIC domain] -----
|
[MSI domain] --------[Remapping domain] ----- [ Vector domain ]
| (optional) |
[HPET MSI domain] ----- |
|
[DMAR domain] -----------------------------
|
[Legacy domain] -----------------------------
This now reflects the actual hardware and allowed us to distangle
the domain specific code from the underlying parent domain, which
can be optional in the case of interrupt remapping. It's a clear
separation of functionality and removes quite some duct tape
constructs which plugged the remap code between ioapic/msi/hpet
and the vector management.
- Intel IOMMU IRQ remapping enhancements, to allow direct interrupt
injection into guests (Feng Wu)
* x86/asm changes:
- Tons of cleanups and small speedups, micro-optimizations. This
is in preparation to move a good chunk of the low level entry
code from assembly to C code (Denys Vlasenko, Andy Lutomirski,
Brian Gerst)
- Moved all system entry related code to a new home under
arch/x86/entry/ (Ingo Molnar)
- Removal of the fragile and ugly CFI dwarf debuginfo annotations.
Conversion to C will reintroduce many of them - but meanwhile
they are only getting in the way, and the upstream kernel does
not rely on them (Ingo Molnar)
- NOP handling refinements. (Borislav Petkov)
* x86/mm changes:
- Big PAT and MTRR rework: making the code more robust and
preparing to phase out exposing direct MTRR interfaces to drivers -
in favor of using PAT driven interfaces (Toshi Kani, Luis R
Rodriguez, Borislav Petkov)
- New ioremap_wt()/set_memory_wt() interfaces to support
Write-Through cached memory mappings. This is especially
important for good performance on NVDIMM hardware (Toshi Kani)
* x86/ras changes:
- Add support for deferred errors on AMD (Aravind Gopalakrishnan)
This is an important RAS feature which adds hardware support for
poisoned data. That means roughly that the hardware marks data
which it has detected as corrupted but wasn't able to correct, as
poisoned data and raises an APIC interrupt to signal that in the
form of a deferred error. It is the OS's responsibility then to
take proper recovery action and thus prolonge system lifetime as
far as possible.
- Add support for Intel "Local MCE"s: upcoming CPUs will support
CPU-local MCE interrupts, as opposed to the traditional system-
wide broadcasted MCE interrupts (Ashok Raj)
- Misc cleanups (Borislav Petkov)
* x86/platform changes:
- Intel Atom SoC updates
... and lots of other cleanups, fixlets and other changes - see the
shortlog and the Git log for details"
* 'x86-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (222 commits)
x86/hpet: Use proper hpet device number for MSI allocation
x86/hpet: Check for irq==0 when allocating hpet MSI interrupts
x86/mm/pat, drivers/infiniband/ipath: Use arch_phys_wc_add() and require PAT disabled
x86/mm/pat, drivers/media/ivtv: Use arch_phys_wc_add() and require PAT disabled
x86/platform/intel/baytrail: Add comments about why we disabled HPET on Baytrail
genirq: Prevent crash in irq_move_irq()
genirq: Enhance irq_data_to_desc() to support hierarchy irqdomain
iommu, x86: Properly handle posted interrupts for IOMMU hotplug
iommu, x86: Provide irq_remapping_cap() interface
iommu, x86: Setup Posted-Interrupts capability for Intel iommu
iommu, x86: Add cap_pi_support() to detect VT-d PI capability
iommu, x86: Avoid migrating VT-d posted interrupts
iommu, x86: Save the mode (posted or remapped) of an IRTE
iommu, x86: Implement irq_set_vcpu_affinity for intel_ir_chip
iommu: dmar: Provide helper to copy shared irte fields
iommu: dmar: Extend struct irte for VT-d Posted-Interrupts
iommu: Add new member capability to struct irq_remap_ops
x86/asm/entry/64: Disentangle error_entry/exit gsbase/ebx/usermode code
x86/asm/entry/32: Shorten __audit_syscall_entry() args preparation
x86/asm/entry/32: Explain reloading of registers after __audit_syscall_entry()
...
Pull x86 FPU updates from Ingo Molnar:
"This tree contains two main changes:
- The big FPU code rewrite: wide reaching cleanups and reorganization
that pulls all the FPU code together into a clean base in
arch/x86/fpu/.
The resulting code is leaner and faster, and much easier to
understand. This enables future work to further simplify the FPU
code (such as removing lazy FPU restores).
By its nature these changes have a substantial regression risk: FPU
code related bugs are long lived, because races are often subtle
and bugs mask as user-space failures that are difficult to track
back to kernel side backs. I'm aware of no unfixed (or even
suspected) FPU related regression so far.
- MPX support rework/fixes. As this is still not a released CPU
feature, there were some buglets in the code - should be much more
robust now (Dave Hansen)"
* 'x86-fpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (250 commits)
x86/fpu: Fix double-increment in setup_xstate_features()
x86/mpx: Allow 32-bit binaries on 64-bit kernels again
x86/mpx: Do not count MPX VMAs as neighbors when unmapping
x86/mpx: Rewrite the unmap code
x86/mpx: Support 32-bit binaries on 64-bit kernels
x86/mpx: Use 32-bit-only cmpxchg() for 32-bit apps
x86/mpx: Introduce new 'directory entry' to 'addr' helper function
x86/mpx: Add temporary variable to reduce masking
x86: Make is_64bit_mm() widely available
x86/mpx: Trace allocation of new bounds tables
x86/mpx: Trace the attempts to find bounds tables
x86/mpx: Trace entry to bounds exception paths
x86/mpx: Trace #BR exceptions
x86/mpx: Introduce a boot-time disable flag
x86/mpx: Restrict the mmap() size check to bounds tables
x86/mpx: Remove redundant MPX_BNDCFG_ADDR_MASK
x86/mpx: Clean up the code by not passing a task pointer around when unnecessary
x86/mpx: Use the new get_xsave_field_ptr()API
x86/fpu/xstate: Wrap get_xsave_addr() to make it safer
x86/fpu/xstate: Fix up bad get_xsave_addr() assumptions
...
The former duplicate the functionalities of the latter but are
neither documented nor arch-independent.
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Benoit Cousson <bcousson@baylibre.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Jean Delvare <jdelvare@suse.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Drokin <oleg.drokin@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Link: http://lkml.kernel.org/r/1432645896-12588-9-git-send-email-bgolaszewski@baylibre.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This unifies all the FPU related header files under a unified, hiearchical
naming scheme:
- asm/fpu/types.h: FPU related data types, needed for 'struct task_struct',
widely included in almost all kernel code, and hence kept
as small as possible.
- asm/fpu/api.h: FPU related 'public' methods exported to other subsystems.
- asm/fpu/internal.h: FPU subsystem internal methods
- asm/fpu/xsave.h: XSAVE support internal methods
(Also standardize the header guard in asm/fpu/internal.h.)
Reviewed-by: Borislav Petkov <bp@alien8.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Fix a minor header file dependency bug in asm/fpu-internal.h: it
relies on i387.h but does not include it. All users of fpu-internal.h
included it explicitly.
Also remove unnecessary includes, to reduce compilation time.
This also makes it easier to use it as a standalone header file
for FPU internals, such as an upcoming C module in arch/x86/kernel/fpu/.
Reviewed-by: Borislav Petkov <bp@alien8.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
So while testing kernels using tools/kvm/ (kvmtool) I noticed that it
booted super slow:
[ 0.142991] Performance Events: no PMU driver, software events only.
[ 0.149265] x86: Booting SMP configuration:
[ 0.149765] .... node #0, CPUs: #1
[ 0.148304] kvm-clock: cpu 1, msr 2:1bfe9041, secondary cpu clock
[ 10.158813] KVM setup async PF for cpu 1
[ 10.159000] #2
[ 10.159000] kvm-stealtime: cpu 1, msr 211a4d400
[ 10.158829] kvm-clock: cpu 2, msr 2:1bfe9081, secondary cpu clock
[ 20.167805] KVM setup async PF for cpu 2
[ 20.168000] #3
[ 20.168000] kvm-stealtime: cpu 2, msr 211a8d400
[ 20.167818] kvm-clock: cpu 3, msr 2:1bfe90c1, secondary cpu clock
[ 30.176902] KVM setup async PF for cpu 3
[ 30.177000] #4
[ 30.177000] kvm-stealtime: cpu 3, msr 211acd400
One CPU booted up per 10 seconds. With 120 CPUs that takes a while.
Bisection pinpointed this commit:
853b160aaa ("Revert f5d6a52f51 ("x86/smpboot: Skip delays during SMP initialization similar to Xen")")
But that commit just restores previous behavior, so it cannot cause the
problem. After some head scratching it turns out that these two commits:
1a744cb356 ("x86/smp/boot: Remove 10ms delay from cpu_up() on modern processors")
d68921f9bd ("x86/smp/boot: Add cmdline "cpu_init_udelay=N" to specify cpu_up() delay")
added the following code to smpboot.c:
- mdelay(10);
+ mdelay(init_udelay);
Note the mismatch in the units: the delay is called 'udelay' and is set
to microseconds - while the function used here is actually 'mdelay',
which counts in milliseconds ...
So the delay for legacy systems is off by a factor of 1,000, so instead
of 10 msecs we waited for 10 seconds ...
The reason bisection pointed to 853b160aaa was that 853b160aaa removed
a (broken) boot-time speedup patch, which masked the factor 1,000 bug.
Fix it by using udelay(). This fixes my bootup problems.
Cc: Len Brown <len.brown@intel.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jan H. Schönherr <jschoenh@amazon.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Huang Ying reported x86 boot hangs due to this commit.
Turns out that the change, despite its changelog, does more
than just change timeouts: it also changes the way we
assert/deassert INIT via the APIC_DM_INIT IPI, in the x2apic
case it skips the deassert step.
This is historically fragile code and the patch did not
improve it, so revert these changes.
This commit:
1a744cb356 ("x86/smp/boot: Remove 10ms delay from cpu_up() on modern processors")
independently removes the worst of the delays (the 10 msec delay).
The remaining delays can be addressed one by one, combined
with careful testing.
Reported-by: Huang Ying <ying.huang@intel.com>
Cc: Anthony Liguori <aliguori@amazon.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Gang Wei <gang.wei@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jan H. Schönherr <jschoenh@amazon.de>
Cc: Len Brown <len.brown@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tim Deegan <tim@xen.org>
Link: http://lkml.kernel.org/r/1430732554-7294-1-git-send-email-jschoenh@amazon.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Modern processor familes do not require the 10ms delay
in cpu_up() to de-assert INIT. This speeds up boot
and resume by 10ms per (application) processor.
Signed-off-by: Len Brown <len.brown@intel.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jan H. Schönherr <jschoenh@amazon.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/021ce30c88f216ad39686646421194dc25671e55.1431379433.git.len.brown@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
No change to default behavior.
Replace the hard-coded mdelay(10) in cpu_up() with a variable
udelay, that is set to a defined default -- rather than a magic
number.
Add a boot-time override, "cpu_init_udelay=N"
Signed-off-by: Len Brown <len.brown@intel.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jan H. Schönherr <jschoenh@amazon.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/2fe8e6c798e8def271122f62df9bbf58dc283e2a.1431379433.git.len.brown@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Remove the per-CPU delays during SMP initialization, which seems
to be possible on newer architectures with an x2APIC.
Xen does this since 2011. In fact, this commit is basically a
combination of the following Xen commits. The first removes the
delays, the second fixes an issue with the removal:
commit 68fce206f6dba9981e8322269db49692c95ce250
Author: Tim Deegan <Tim.Deegan@citrix.com>
Date: Tue Jul 19 14:13:01 2011 +0100
x86: Remove timeouts from INIT-SIPI-SIPI sequence when using x2apic.
Some of the timeouts are pointless since they're waiting for the ICR
to ack the IPI delivery and that doesn't happen on x2apic.
The others should be benign (and are suggested in the SDM) but
removing them makes AP bringup much more reliable on some test boxes.
Signed-off-by: Tim Deegan <Tim.Deegan@citrix.com>
commit f12ee533150761df5a7099c83f2a5fa6c07d1187
Author: Gang Wei <gang.wei@intel.com>
Date: Thu Dec 29 10:07:54 2011 +0000
X86: Add a delay between INIT & SIPIs for tboot AP bring-up in X2APIC case
Without this delay, Xen could not bring APs up while working with
TXT/tboot, because tboot needs some time in APs to handle INIT before
becoming ready for receiving SIPIs (this delay was removed as part of
c/s 23724 by Tim Deegan).
Signed-off-by: Gang Wei <gang.wei@intel.com>
Acked-by: Keir Fraser <keir@xen.org>
Acked-by: Tim Deegan <tim@xen.org>
Committed-by: Tim Deegan <tim@xen.org>
Signed-off-by: Jan H. Schönherr <jschoenh@amazon.de>
Cc: Anthony Liguori <aliguori@amazon.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Gang Wei <gang.wei@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tim Deegan <tim@xen.org>
Link: http://lkml.kernel.org/r/1430732554-7294-1-git-send-email-jschoenh@amazon.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull RCU changes from Ingo Molnar:
"The main changes in this cycle were:
- changes permitting use of call_rcu() and friends very early in
boot, for example, before rcu_init() is invoked.
- add in-kernel API to enable and disable expediting of normal RCU
grace periods.
- improve RCU's handling of (hotplug-) outgoing CPUs.
- NO_HZ_FULL_SYSIDLE fixes.
- tiny-RCU updates to make it more tiny.
- documentation updates.
- miscellaneous fixes"
* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (58 commits)
cpu: Provide smpboot_thread_init() on !CONFIG_SMP kernels as well
cpu: Defer smpboot kthread unparking until CPU known to scheduler
rcu: Associate quiescent-state reports with grace period
rcu: Yet another fix for preemption and CPU hotplug
rcu: Add diagnostics to grace-period cleanup
rcutorture: Default to grace-period-initialization delays
rcu: Handle outgoing CPUs on exit from idle loop
cpu: Make CPU-offline idle-loop transition point more precise
rcu: Eliminate ->onoff_mutex from rcu_node structure
rcu: Process offlining and onlining only at grace-period start
rcu: Move rcu_report_unblock_qs_rnp() to common code
rcu: Rework preemptible expedited bitmask handling
rcu: Remove event tracing from rcu_cpu_notify(), used by offline CPUs
rcutorture: Enable slow grace-period initializations
rcu: Provide diagnostic option to slow down grace-period initialization
rcu: Detect stalls caused by failure to propagate up rcu_node tree
rcu: Eliminate empty HOTPLUG_CPU ifdef
rcu: Simplify sync_rcu_preempt_exp_init()
rcu: Put all orphan-callback-related code under same comment
rcu: Consolidate offline-CPU callback initialization
...
Pull x86 asm changes from Ingo Molnar:
"There were lots of changes in this development cycle:
- over 100 separate cleanups, restructuring changes, speedups and
fixes in the x86 system call, irq, trap and other entry code, part
of a heroic effort to deobfuscate a decade old spaghetti asm code
and its C code dependencies (Denys Vlasenko, Andy Lutomirski)
- alternatives code fixes and enhancements (Borislav Petkov)
- simplifications and cleanups to the compat code (Brian Gerst)
- signal handling fixes and new x86 testcases (Andy Lutomirski)
- various other fixes and cleanups
By their nature many of these changes are risky - we tried to test
them well on many different x86 systems (there are no known
regressions), and they are split up finely to help bisection - but
there's still a fair bit of residual risk left so caveat emptor"
* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (148 commits)
perf/x86/64: Report regs_user->ax too in get_regs_user()
perf/x86/64: Simplify regs_user->abi setting code in get_regs_user()
perf/x86/64: Do report user_regs->cx while we are in syscall, in get_regs_user()
perf/x86/64: Do not guess user_regs->cs, ss, sp in get_regs_user()
x86/asm/entry/32: Tidy up JNZ instructions after TESTs
x86/asm/entry/64: Reduce padding in execve stubs
x86/asm/entry/64: Remove GET_THREAD_INFO() in ret_from_fork
x86/asm/entry/64: Simplify jumps in ret_from_fork
x86/asm/entry/64: Remove a redundant jump
x86/asm/entry/64: Optimize [v]fork/clone stubs
x86/asm/entry: Zero EXTRA_REGS for stub32_execve() too
x86/asm/entry/64: Move stub_x32_execvecloser() to stub_execveat()
x86/asm/entry/64: Use common code for rt_sigreturn() epilogue
x86/asm/entry/64: Add forgotten CFI annotation
x86/asm/entry/irq: Simplify interrupt dispatch table (IDT) layout
x86/asm/entry/64: Move opportunistic sysret code to syscall code path
x86, selftests: Add sigreturn selftest
x86/alternatives: Guard NOPs optimization
x86/asm/entry: Clear EXTRA_REGS for all executable formats
x86/signal: Remove pax argument from restore_sigcontext
...
Some of x86 bare-metal and Xen CPU initialization code is common
between the two and therefore can be factored out to avoid code
duplication.
As a side effect, doing so will also extend the fix provided by
commit a7fcf28d43 ("x86/asm/entry: Replace this_cpu_sp0() with
current_top_of_stack() to x86_32") to 32-bit Xen PV guests.
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: konrad.wilk@oracle.com
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/1427897534-5086-1-git-send-email-boris.ostrovsky@oracle.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
__verify_local_APIC() is detritus from the early APIC days.
Its return value isn't used anywhere and the information it
prints when debug is enabled is already part of APIC
initialization messages printed to syslog. Off with it!
Signed-off-by: Bandan Das <bsd@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/jpgy4mcsxsq.fsf@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
PER_CPU_VAR(kernel_stack) was set up in a way where it points
five stack slots below the top of stack.
Presumably, it was done to avoid one "sub $5*8,%rsp"
in syscall/sysenter code paths, where iret frame needs to be
created by hand.
Ironically, none of them benefits from this optimization,
since all of them need to allocate additional data on stack
(struct pt_regs), so they still have to perform subtraction.
This patch eliminates KERNEL_STACK_OFFSET.
PER_CPU_VAR(kernel_stack) now points directly to top of stack.
pt_regs allocations are adjusted to allocate iret frame as well.
Hopefully we can merge it later with 32-bit specific
PER_CPU_VAR(cpu_current_top_of_stack) variable...
Net result in generated code is that constants in several insns
are changed.
This change is necessary for changing struct pt_regs creation
in SYSCALL64 code path from MOV to PUSH instructions.
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Acked-by: Borislav Petkov <bp@suse.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1426785469-15125-2-git-send-email-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit removes the open-coded CPU-offline notification with new
common code. Among other things, this change avoids calling scheduler
code using RCU from an offline CPU that RCU is ignoring. It also allows
Xen to notice at online time that the CPU did not go offline correctly.
Note that Xen has the surviving CPU carry out some cleanup operations,
so if the surviving CPU times out, these cleanup operations might have
been carried out while the outgoing CPU was still running. It might
therefore be unwise to bring this CPU back online, and this commit
avoids doing so.
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: <x86@kernel.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: <xen-devel@lists.xenproject.org>
I broke 32-bit kernels. The implementation of sp0 was correct
as far as I can tell, but sp0 was much weirder on x86_32 than I
realized. It has the following issues:
- Init's sp0 is inconsistent with everything else's: non-init tasks
are offset by 8 bytes. (I have no idea why, and the comment is unhelpful.)
- vm86 does crazy things to sp0.
Fix it up by replacing this_cpu_sp0() with
current_top_of_stack() and using a new percpu variable to track
the top of the stack on x86_32.
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 75182b1632 ("x86/asm/entry: Switch all C consumers of kernel_stack to this_cpu_sp0()")
Link: http://lkml.kernel.org/r/d09dbe270883433776e0cbee3c7079433349e96d.1425692936.git.luto@amacapital.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Now that the APIC bringup is consolidated we can move the setup call
for the percpu clock event device to apic_bsp_setup().
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Link: http://lkml.kernel.org/r/20150115211704.162567839@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Extend apic_bsp_setup() so the same code flow can be used for
APIC_init_uniprocessor().
Folded Jiangs fix to provide proper ordering of the UP setup.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Link: http://lkml.kernel.org/r/20150115211704.084765674@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The UP related setups for local apic are mangled into smp_sanity_check().
That results in duplicate calls to disable_smp() and makes the code
hard to follow. Let smp_sanity_check() return dedicated values for the
various exit reasons and handle them at the call site.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Borislav Petkov <bp@alien8.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/20150115211703.987833932@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
We better provide proper functions which implement the required code
flow in the apic code rather than letting the smpboot code open code
it. That allows to make more functions static and confines the APIC
functionality to apic.c where it belongs.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Borislav Petkov <bp@alien8.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/20150115211703.907616730@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
smpboot is very creative with the ways to disable ioapic.
smpboot_clear_io_apic() smpboot_clear_io_apic_irqs() and
disable_ioapic_support() serve a similar purpose.
smpboot_clear_io_apic_irqs() is the most useless of all
functions as it clears a variable which has not been setup yet.
Aside of that it has the same ifdef mess and conditionals around the
ioapic related code, which can now be removed.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Borislav Petkov <bp@alien8.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/20150115211703.650280684@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
No point for a separate header file.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Link: http://lkml.kernel.org/r/20150115211703.304126687@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
There is no reason to keep preemption disabled in this function.
We only have two other threads live: kthreadd and idle. Neither of
them is going to preempt. But that preempt_disable forces all the code
inside to do GFP_ATOMIC allocations which is just insane.
Remove it.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Borislav Petkov <bp@alien8.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: x86@kernel.org
Link: http://lkml.kernel.org/r/20141205084147.153643952@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Pull x86 boot and percpu updates from Ingo Molnar:
"This tree contains a bootable images documentation update plus three
slightly misplaced x86/asm percpu changes/optimizations"
* 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86-64: Use RIP-relative addressing for most per-CPU accesses
x86-64: Handle PC-relative relocations on per-CPU data
x86: Convert a few more per-CPU items to read-mostly ones
x86, boot: Document intermediates more clearly
Commit 2ed53c0d6c ("x86/smpboot: Speed up suspend/resume by
avoiding 100ms sleep for CPU offline during S3") introduced
completions to CPU offlining process. These completions are not
initialized on Xen kernels causing a panic in
play_dead_common().
Move handling of die_complete into common routines to make them
available to Xen guests.
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Cc: tianyu.lan@intel.com
Cc: konrad.wilk@oracle.com
Cc: xen-devel@lists.xenproject.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1414770572-7950-1-git-send-email-boris.ostrovsky@oracle.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Both this_cpu_off and cpu_info aren't getting modified post boot, yet
are being accessed on enough code paths that grouping them with other
frequently read items seems desirable. For cpu_info this at the same
time implies removing the cache line alignment (which afaict became
pointless when it got converted to per-CPU data years ago).
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Link: http://lkml.kernel.org/r/54589BD20200007800044A84@mail.emea.novell.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Makes the code more readable by moving variable and usage closer
to each other, which also avoids this build warning in the
!CONFIG_HOTPLUG_CPU case:
arch/x86/kernel/smpboot.c:105:42: warning: ‘die_complete’ defined but not used [-Wunused-variable]
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Lan Tianyu <tianyu.lan@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: srostedt@redhat.com
Cc: toshi.kani@hp.com
Cc: imammedo@redhat.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1409039025-32310-1-git-send-email-tianyu.lan@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull x86 cpu offlining patch from Ingo Molnar:
"This tree includes a single commit that speeds up x86 suspend/resume
by replacing a naive 100msec sleep based polling loop with proper
completion notification.
This gives some real suspend/resume benefit on servers with larger
core counts"
* 'x86-cpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/smpboot: Speed up suspend/resume by avoiding 100ms sleep for CPU offline during S3
Pull x86 bootup updates from Ingo Molnar:
"The changes in this cycle were:
- Fix rare SMP-boot hang (mostly in virtual environments)
- Fix build warning with certain (rare) toolchains"
* 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/relocs: Make per_cpu_load_addr static
x86/smpboot: Initialize secondary CPU only if master CPU will wait for it
Pull scheduler updates from Ingo Molnar:
"The main changes in this cycle were:
- Optimized support for Intel "Cluster-on-Die" (CoD) topologies (Dave
Hansen)
- Various sched/idle refinements for better idle handling (Nicolas
Pitre, Daniel Lezcano, Chuansheng Liu, Vincent Guittot)
- sched/numa updates and optimizations (Rik van Riel)
- sysbench speedup (Vincent Guittot)
- capacity calculation cleanups/refactoring (Vincent Guittot)
- Various cleanups to thread group iteration (Oleg Nesterov)
- Double-rq-lock removal optimization and various refactorings
(Kirill Tkhai)
- various sched/deadline fixes
... and lots of other changes"
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (72 commits)
sched/dl: Use dl_bw_of() under rcu_read_lock_sched()
sched/fair: Delete resched_cpu() from idle_balance()
sched, time: Fix build error with 64 bit cputime_t on 32 bit systems
sched: Improve sysbench performance by fixing spurious active migration
sched/x86: Fix up typo in topology detection
x86, sched: Add new topology for multi-NUMA-node CPUs
sched/rt: Use resched_curr() in task_tick_rt()
sched: Use rq->rd in sched_setaffinity() under RCU read lock
sched: cleanup: Rename 'out_unlock' to 'out_free_new_mask'
sched: Use dl_bw_of() under RCU read lock
sched/fair: Remove duplicate code from can_migrate_task()
sched, mips, ia64: Remove __ARCH_WANT_UNLOCKED_CTXSW
sched: print_rq(): Don't use tasklist_lock
sched: normalize_rt_tasks(): Don't use _irqsave for tasklist_lock, use task_rq_lock()
sched: Fix the task-group check in tg_has_rt_tasks()
sched/fair: Leverage the idle state info when choosing the "idlest" cpu
sched: Let the scheduler see CPU idle states
sched/deadline: Fix inter- exclusive cpusets migrations
sched/deadline: Clear dl_entity params when setscheduling to different class
sched/numa: Kill the wrong/dead TASK_DEAD check in task_numa_fault()
...
Commit:
cebf15eb09 ("x86, sched: Add new topology for multi-NUMA-node CPUs")
some code to try to detect the situation where we have a NUMA node
inside of the "DIE" sched domain.
It detected this by looking for cpus which match_die() but do not match
NUMA nodes via topology_same_node().
I wrote it up as:
if (match_die(c, o) == !topology_same_node(c, o))
which actually seemed to work some of the time, albiet
accidentally.
It should have been doing an &&, not an ==.
This code essentially chopped off the "DIE" domain on one of
Andrew Morton's systems. He reported that this patch fixed his
issue.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Dave Hansen <dave@sr71.net>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Lan Tianyu <tianyu.lan@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Toshi Kani <toshi.kani@hp.com>
Link: http://lkml.kernel.org/r/20140930214546.FD481CFF@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The following bug can be triggered by hot adding and removing a large number of
xen domain0's vcpus repeatedly:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000004 IP: [..] find_busiest_group
PGD 5a9d5067 PUD 13067 PMD 0
Oops: 0000 [#3] SMP
[...]
Call Trace:
load_balance
? _raw_spin_unlock_irqrestore
idle_balance
__schedule
schedule
schedule_timeout
? lock_timer_base
schedule_timeout_uninterruptible
msleep
lock_device_hotplug_sysfs
online_store
dev_attr_store
sysfs_write_file
vfs_write
SyS_write
system_call_fastpath
Last level cache shared mask is built during CPU up and the
build_sched_domain() routine takes advantage of it to setup
the sched domain CPU topology.
However, llc_shared_mask is not released during CPU disable,
which leads to an invalid sched domainCPU topology.
This patch fix it by releasing the llc_shared_mask correctly
during CPU disable.
Yasuaki also reported that this can happen on real hardware:
https://lkml.org/lkml/2014/7/22/1018
His case is here:
==
Here is an example on my system.
My system has 4 sockets and each socket has 15 cores and HT is
enabled. In this case, each core of sockes is numbered as
follows:
| CPU#
Socket#0 | 0-14 , 60-74
Socket#1 | 15-29, 75-89
Socket#2 | 30-44, 90-104
Socket#3 | 45-59, 105-119
Then llc_shared_mask of CPU#30 has 0x3fff80000001fffc0000000.
It means that last level cache of Socket#2 is shared with
CPU#30-44 and 90-104.
When hot-removing socket#2 and #3, each core of sockets is
numbered as follows:
| CPU#
Socket#0 | 0-14 , 60-74
Socket#1 | 15-29, 75-89
But llc_shared_mask is not cleared. So llc_shared_mask of CPU#30
remains having 0x3fff80000001fffc0000000.
After that, when hot-adding socket#2 and #3, each core of
sockets is numbered as follows:
| CPU#
Socket#0 | 0-14 , 60-74
Socket#1 | 15-29, 75-89
Socket#2 | 30-59
Socket#3 | 90-119
Then llc_shared_mask of CPU#30 becomes
0x3fff8000fffffffc0000000. It means that last level cache of
Socket#2 is shared with CPU#30-59 and 90-104. So the mask has
the wrong value.
Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com>
Tested-by: Linn Crosetto <linn@hp.com>
Reviewed-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Toshi Kani <toshi.kani@hp.com>
Reviewed-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: <stable@vger.kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1411547885-48165-1-git-send-email-wanpeng.li@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
With certain kernel configurations, CPU offline consumes more than
100ms during S3.
It's a timing related issue: native_cpu_die() would occasionally fall
into a 100ms sleep when the CPU idle loop thread marked the CPU state
to DEAD too slowly.
What native_cpu_die() does is that it polls the CPU state and waits
for 100ms if CPU state hasn't been marked to DEAD. The 100ms sleep
doesn't make sense and is purely historic.
To avoid such long sleeping, this patch adds a 'struct completion'
to each CPU, waits for the completion in native_cpu_die() and wakes
up the completion when the CPU state is marked to DEAD.
Tested on an Intel Xeon server with 48 cores, Ivybridge and on
Haswell laptops. The CPU offlining cost on these machines is
reduced from more than 100ms to less than 5ms. The system
suspend time is reduced by 2.3s on the servers.
Borislav and Prarit also helped to test the patch on an AMD
machine and a few systems of various sizes and configurations
(multi-socket, single-socket, no hyper threading, etc.). No
issues were seen.
Tested-by: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: Lan Tianyu <tianyu.lan@intel.com>
Acked-by: Borislav Petkov <bp@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: srostedt@redhat.com
Cc: toshi.kani@hp.com
Cc: imammedo@redhat.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1409039025-32310-1-git-send-email-tianyu.lan@intel.com
[ Improved a few minor details in the code, cleaned up the changelog. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
I'm getting the spew below when booting with Haswell (Xeon
E5-2699 v3) CPUs and the "Cluster-on-Die" (CoD) feature enabled
in the BIOS. It seems similar to the issue that some folks from
AMD ran in to on their systems and addressed in this commit:
161270fc1f ("x86/smp: Fix topology checks on AMD MCM CPUs")
Both these Intel and AMD systems break an assumption which is
being enforced by topology_sane(): a socket may not contain more
than one NUMA node.
AMD special-cased their system by looking for a cpuid flag. The
Intel mode is dependent on BIOS options and I do not know of a
way which it is enumerated other than the tables being parsed
during the CPU bringup process. In other words, we have to trust
the ACPI tables <shudder>.
This detects the situation where a NUMA node occurs at a place in
the middle of the "CPU" sched domains. It replaces the default
topology with one that relies on the NUMA information from the
firmware (SRAT table) for all levels of sched domains above the
hyperthreads.
This also fixes a sysfs bug. We used to freak out when we saw
the "mc" group cross a node boundary, so we stopped building the
MC group. MC gets exported as the 'core_siblings_list' in
/sys/devices/system/cpu/cpu*/topology/ and this caused CPUs with
the same 'physical_package_id' to not be listed together in
'core_siblings_list'. This violates a statement from
Documentation/ABI/testing/sysfs-devices-system-cpu:
core_siblings: internal kernel map of cpu#'s hardware threads
within the same physical_package_id.
core_siblings_list: human-readable list of the logical CPU
numbers within the same physical_package_id as cpu#.
The sysfs effects here cause an issue with the hwloc tool where
it gets confused and thinks there are more sockets than are
physically present.
Before this patch, there are two packages:
# cd /sys/devices/system/cpu/
# cat cpu*/topology/physical_package_id | sort | uniq -c
18 0
18 1
But 4 _sets_ of core siblings:
# cat cpu*/topology/core_siblings_list | sort | uniq -c
9 0-8
9 18-26
9 27-35
9 9-17
After this set, there are only 2 sets of core siblings, which
is what we expect for a 2-socket system.
# cat cpu*/topology/physical_package_id | sort | uniq -c
18 0
18 1
# cat cpu*/topology/core_siblings_list | sort | uniq -c
18 0-17
18 18-35
Example spew:
...
NMI watchdog: enabled on all CPUs, permanently consumes one hw-PMU counter.
#2#3#4#5#6#7#8
.... node #1, CPUs: #9
------------[ cut here ]------------
WARNING: CPU: 9 PID: 0 at /home/ak/hle/linux-hle-2.6/arch/x86/kernel/smpboot.c:306 topology_sane.isra.2+0x74/0x90()
sched: CPU #9's mc-sibling CPU #0 is not on the same node! [node: 1 != 0]. Ignoring dependency.
Modules linked in:
CPU: 9 PID: 0 Comm: swapper/9 Not tainted 3.17.0-rc1-00293-g8e01c4d-dirty #631
Hardware name: Intel Corporation S2600WTT/S2600WTT, BIOS GRNDSDP1.86B.0036.R05.1407140519 07/14/2014
0000000000000009 ffff88046ddabe00 ffffffff8172e485 ffff88046ddabe48
ffff88046ddabe38 ffffffff8109691d 000000000000b001 0000000000000009
ffff88086fc12580 000000000000b020 0000000000000009 ffff88046ddabe98
Call Trace:
[<ffffffff8172e485>] dump_stack+0x45/0x56
[<ffffffff8109691d>] warn_slowpath_common+0x7d/0xa0
[<ffffffff8109698c>] warn_slowpath_fmt+0x4c/0x50
[<ffffffff81074f94>] topology_sane.isra.2+0x74/0x90
[<ffffffff8107530e>] set_cpu_sibling_map+0x31e/0x4f0
[<ffffffff8107568d>] start_secondary+0x1ad/0x240
---[ end trace 3fe5f587a9fcde61 ]---
#10#11#12#13#14#15#16#17
.... node #2, CPUs: #18#19#20#21#22#23#24#25#26
.... node #3, CPUs: #27#28#29#30#31#32#33#34#35
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
[ Added LLC domain and s/match_mc/match_die/ ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: brice.goglin@gmail.com
Cc: "H. Peter Anvin" <hpa@linux.intel.com>
Link: http://lkml.kernel.org/r/20140918193334.C065EBCE@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Hang is observed on virtual machines during CPU hotplug,
especially in big guests with many CPUs. (It reproducible
more often if host is over-committed).
It happens because master CPU gives up waiting on
secondary CPU and allows it to run wild. As result
AP causes locking or crashing system. For example
as described here:
https://lkml.org/lkml/2014/3/6/257
If master CPU have sent STARTUP IPI successfully,
and AP signalled to master CPU that it's ready
to start initialization, make master CPU wait
indefinitely till AP is onlined.
To ensure that AP won't ever run wild, make it
wait at early startup till master CPU confirms its
intention to wait for AP. If AP doesn't respond in 10
seconds, the master CPU will timeout and cancel
AP onlining.
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Acked-by: Toshi Kani <toshi.kani@hp.com>
Tested-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/1403266991-12233-1-git-send-email-imammedo@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
