We still patch SMP instructions to UP variants if we boot with a
single CPU, but not at any other time. In particular, not if we
unplug CPUs to return to a single cpu.
Paul McKenney points out:
mean offline overhead is 6251/48=130.2 milliseconds.
If I remove the alternatives_smp_switch() from the offline
path [...] the mean offline overhead is 550/42=13.1 milliseconds
Basically, we're never going to get those 120ms back, and the
code is pretty messy.
We get rid of:
1) The "smp-alt-once" boot option. It's actually "smp-alt-boot", the
documentation is wrong. It's now the default.
2) The skip_smp_alternatives flag used by suspend.
3) arch_disable_nonboot_cpus_begin() and arch_disable_nonboot_cpus_end()
which were only used to set this one flag.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Paul McKenney <paul.mckenney@us.ibm.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/87vcgwwive.fsf@rustcorp.com.au
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull x86/mm changes from Peter Anvin:
"The big change here is the patchset by Alex Shi to use INVLPG to flush
only the affected pages when we only need to flush a small page range.
It also removes the special INVALIDATE_TLB_VECTOR interrupts (32
vectors!) and replace it with an ordinary IPI function call."
Fix up trivial conflicts in arch/x86/include/asm/apic.h (added code next
to changed line)
* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/tlb: Fix build warning and crash when building for !SMP
x86/tlb: do flush_tlb_kernel_range by 'invlpg'
x86/tlb: replace INVALIDATE_TLB_VECTOR by CALL_FUNCTION_VECTOR
x86/tlb: enable tlb flush range support for x86
mm/mmu_gather: enable tlb flush range in generic mmu_gather
x86/tlb: add tlb_flushall_shift knob into debugfs
x86/tlb: add tlb_flushall_shift for specific CPU
x86/tlb: fall back to flush all when meet a THP large page
x86/flush_tlb: try flush_tlb_single one by one in flush_tlb_range
x86/tlb_info: get last level TLB entry number of CPU
x86: Add read_mostly declaration/definition to variables from smp.h
x86: Define early read-mostly per-cpu macros
Pull debug-for-linus git tree from Ingo Molnar.
Fix up trivial conflict in arch/x86/kernel/cpu/perf_event_intel.c due to
a printk() having changed to a pr_info() differently in the two branches.
* 'x86-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86: Move call to print_modules() out of show_regs()
x86/mm: Mark free_initrd_mem() as __init
x86/microcode: Mark microcode_id[] as __initconst
x86/nmi: Clean up register_nmi_handler() usage
x86: Save cr2 in NMI in case NMIs take a page fault (for i386)
x86: Remove cmpxchg from i386 NMI nesting code
x86: Save cr2 in NMI in case NMIs take a page fault
x86/debug: Add KERN_<LEVEL> to bare printks, convert printks to pr_<level>
Add "read-mostly" qualifier to the following variables in
smp.h:
- cpu_sibling_map
- cpu_core_map
- cpu_llc_shared_map
- cpu_llc_id
- cpu_number
- x86_cpu_to_apicid
- x86_bios_cpu_apicid
- x86_cpu_to_logical_apicid
As long as all the variables above are only written during the
initialization, this change is meant to prevent the false
sharing. More specifically, on vSMP Foundation platform
x86_cpu_to_apicid shared the same internode_cache_line with
frequently written lapic_events.
From the analysis of the first 33 per_cpu variables out of 219
(memories they describe, to be more specific) the 8 have read_mostly
nature (tlb_vector_offset, cpu_loops_per_jiffy, xen_debug_irq, etc.)
and 25 are frequently written (irq_stack_union, gdt_page,
exception_stacks, idt_desc, etc.).
Assuming that the spread of the rest of the per_cpu variables is
similar, identifying the read mostly memories will make more sense
in terms of long-term code maintenance comparing to identifying
frequently written memories.
Signed-off-by: Vlad Zolotarov <vlad@scalemp.com>
Acked-by: Shai Fultheim <shai@scalemp.com>
Cc: Shai Fultheim (Shai@ScaleMP.com) <Shai@scalemp.com>
Cc: ido@wizery.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1719258.EYKzE4Zbq5@vlad
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The warning below triggers on AMD MCM packages because physical package
IDs on the cores of a _physical_ socket are the same. I.e., this field
says which CPUs belong to the same physical package.
However, the same two CPUs belong to two different internal, i.e.
"logical" nodes in the same physical socket which is reflected in the
CPU-to-node map on x86 with NUMA.
Which makes this check wrong on the above topologies so circumvent it.
[ 0.444413] Booting Node 0, Processors #1#2#3#4#5 Ok.
[ 0.461388] ------------[ cut here ]------------
[ 0.465997] WARNING: at arch/x86/kernel/smpboot.c:310 topology_sane.clone.1+0x6e/0x81()
[ 0.473960] Hardware name: Dinar
[ 0.477170] sched: CPU #6's mc-sibling CPU #0 is not on the same node! [node: 1 != 0]. Ignoring dependency.
[ 0.486860] Booting Node 1, Processors #6
[ 0.491104] Modules linked in:
[ 0.494141] Pid: 0, comm: swapper/6 Not tainted 3.4.0+ #1
[ 0.499510] Call Trace:
[ 0.501946] [<ffffffff8144bf92>] ? topology_sane.clone.1+0x6e/0x81
[ 0.508185] [<ffffffff8102f1fc>] warn_slowpath_common+0x85/0x9d
[ 0.514163] [<ffffffff8102f2b7>] warn_slowpath_fmt+0x46/0x48
[ 0.519881] [<ffffffff8144bf92>] topology_sane.clone.1+0x6e/0x81
[ 0.525943] [<ffffffff8144c234>] set_cpu_sibling_map+0x251/0x371
[ 0.532004] [<ffffffff8144c4ee>] start_secondary+0x19a/0x218
[ 0.537729] ---[ end trace 4eaa2a86a8e2da22 ]---
[ 0.628197] #7#8#9#10#11 Ok.
[ 0.807108] Booting Node 3, Processors #12#13#14#15#16#17 Ok.
[ 0.897587] Booting Node 2, Processors #18#19#20#21#22#23 Ok.
[ 0.917443] Brought up 24 CPUs
We ran a topology sanity check test we have here on it and
it all looks ok... hopefully :).
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Cc: Andreas Herrmann <andreas.herrmann3@amd.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20120529135442.GE29157@aftab.osrc.amd.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Commit 316ad24830 ("sched/x86: Rewrite set_cpu_sibling_map()")
broke the booted_cores accounting.
The problem is that the booted_cores accounting needs all the
sibling links set up. So restore the second loop and add a comment as
to why its needed.
On qemu booted with -smp sockets=1,cores=2,threads=2;
Before:
$ grep cores /proc/cpuinfo
cpu cores : 2
cpu cores : 1
cpu cores : 4
cpu cores : 3
With the patch:
$ grep cores /proc/cpuinfo
cpu cores : 2
cpu cores : 2
cpu cores : 2
cpu cores : 2
Reported-by: Prarit Bhargava <prarit@redhat.com>
Reported-by: Borislav Petkov <bp@amd64.org>
Signed-off-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20120531073738.GH7511@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Use a more current logging style:
- Bare printks should have a KERN_<LEVEL> for consistency's sake
- Add pr_fmt where appropriate
- Neaten some macro definitions
- Convert some Ok output to OK
- Use "%s: ", __func__ in pr_fmt for summit
- Convert some printks to pr_<level>
Message output is not identical in all cases.
Signed-off-by: Joe Perches <joe@perches.com>
Cc: levinsasha928@gmail.com
Link: http://lkml.kernel.org/r/1337655007.24226.10.camel@joe2Laptop
[ merged two similar patches, tidied up the changelog ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
ipi_call_lock/unlock() lock resp. unlock call_function.lock. This lock
protects only the call_function data structure itself, but it's
completely unrelated to cpu_online_mask. The mask to which the IPIs
are sent is calculated before call_function.lock is taken in
smp_call_function_many(), so the locking around set_cpu_online() is
pointless and can be removed.
[ tglx: Massaged changelog ]
Signed-off-by: Yong Zhang <yong.zhang0@gmail.com>
Cc: ralf@linux-mips.org
Cc: sshtylyov@mvista.com
Cc: david.daney@cavium.com
Cc: nikunj@linux.vnet.ibm.com
Cc: paulmck@linux.vnet.ibm.com
Cc: axboe@kernel.dk
Cc: peterz@infradead.org
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Link: http://lkml.kernel.org/r/1338275765-3217-7-git-send-email-yong.zhang0@gmail.com
Acked-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Commit commit 8e7fbcbc2 ("sched: Remove stale power aware scheduling
remnants and dysfunctional knobs") made a boo-boo with removing the
power aware scheduling muck from the x86 topology bits.
We should unconditionally use the llc_shared mask for multi-core.
Reported-and-tested-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Borislav Petkov <bp@amd64.org>
Cc: Andreas Herrmann <andreas.herrmann3@amd.com>
Link: http://lkml.kernel.org/n/tip-lsksc2kfyeveb13avh327p0d@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull x86 trampoline rework from H. Peter Anvin:
"This code reworks all the "trampoline"/"realmode" code (various bits
that need to live in the first megabyte of memory, most but not all of
which runs in real mode at some point) in the kernel into a single
object. The main reason for doing this is that it eliminates the last
place in the kernel where we needed pages to be mapped RWX. This code
separates all that code into proper R/RW/RX pages."
Fix up conflicts in arch/x86/kernel/Makefile (mca removed next to reboot
code), and arch/x86/kernel/reboot.c (reboot code moved around in one
branch, modified in this one), and arch/x86/tools/relocs.c (mostly same
code came in earlier due to working around the ld bugs just before the
3.4 release).
Also remove stale x86-relocs entry from scripts/.gitignore as per Peter
Anvin.
* commit '61f5446169046c217a5479517edac3a890c3bee7': (36 commits)
x86, realmode: Move end signature into header.S
x86, relocs: When printing an error, say relative or absolute
x86, relocs: More relocations which may end up as absolute
x86, relocs: Workaround for binutils 2.22.52.0.1 section bug
xen-acpi-processor: Add missing #include <xen/xen.h>
acpi, bgrd: Add missing <linux/io.h> to drivers/acpi/bgrt.c
x86, realmode: Change EFER to a single u64 field
x86, realmode: Move kernel/realmode.c to realmode/init.c
x86, realmode: Move not-common bits out of trampoline_common.S
x86, realmode: Mask out EFER.LMA when saving trampoline EFER
x86, realmode: Fix no cache bits test in reboot_32.S
x86, realmode: Make sure all generated files are listed in targets
x86, realmode: build fix: remove duplicate build
x86, realmode: read cr4 and EFER from kernel for 64-bit trampoline
x86, realmode: fixes compilation issue in tboot.c
x86, realmode: move relocs from scripts/ to arch/x86/tools
x86, realmode: header for trampoline code
x86, realmode: flattened rm hierachy
x86, realmode: don't copy real_mode_header
x86, realmode: fix 64-bit wakeup sequence
...
Pull scheduler changes from Ingo Molnar:
"The biggest change is the cleanup/simplification of the load-balancer:
instead of the current practice of architectures twiddling scheduler
internal data structures and providing the scheduler domains in
colorfully inconsistent ways, we now have generic scheduler code in
kernel/sched/core.c:sched_init_numa() that looks at the architecture's
node_distance() parameters and (while not fully trusting it) deducts a
NUMA topology from it.
This inevitably changes balancing behavior - hopefully for the better.
There are various smaller optimizations, cleanups and fixlets as well"
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched: Taint kernel with TAINT_WARN after sleep-in-atomic bug
sched: Remove stale power aware scheduling remnants and dysfunctional knobs
sched/debug: Fix printing large integers on 32-bit platforms
sched/fair: Improve the ->group_imb logic
sched/nohz: Fix rq->cpu_load[] calculations
sched/numa: Don't scale the imbalance
sched/fair: Revert sched-domain iteration breakage
sched/x86: Rewrite set_cpu_sibling_map()
sched/numa: Fix the new NUMA topology bits
sched/numa: Rewrite the CONFIG_NUMA sched domain support
sched/fair: Propagate 'struct lb_env' usage into find_busiest_group
sched/fair: Add some serialization to the sched_domain load-balance walk
sched/fair: Let minimally loaded cpu balance the group
sched: Change rq->nr_running to unsigned int
x86/numa: Check for nonsensical topologies on real hw as well
x86/numa: Hard partition cpu topology masks on node boundaries
x86/numa: Allow specifying node_distance() for numa=fake
x86/sched: Make mwait_usable() heed to "idle=" kernel parameters properly
sched: Update documentation and comments
sched_rt: Avoid unnecessary dequeue and enqueue of pushable tasks in set_cpus_allowed_rt()
It's been broken forever (i.e. it's not scheduling in a power
aware fashion), as reported by Suresh and others sending
patches, and nobody cares enough to fix it properly ...
so remove it to make space free for something better.
There's various problems with the code as it stands today, first
and foremost the user interface which is bound to topology
levels and has multiple values per level. This results in a
state explosion which the administrator or distro needs to
master and almost nobody does.
Furthermore large configuration state spaces aren't good, it
means the thing doesn't just work right because it's either
under so many impossibe to meet constraints, or even if
there's an achievable state workloads have to be aware of
it precisely and can never meet it for dynamic workloads.
So pushing this kind of decision to user-space was a bad idea
even with a single knob - it's exponentially worse with knobs
on every node of the topology.
There is a proposal to replace the user interface with a single
3 state knob:
sched_balance_policy := { performance, power, auto }
where 'auto' would be the preferred default which looks at things
like Battery/AC mode and possible cpufreq state or whatever the hw
exposes to show us power use expectations - but there's been no
progress on it in the past many months.
Aside from that, the actual implementation of the various knobs
is known to be broken. There have been sporadic attempts at
fixing things but these always stop short of reaching a mergable
state.
Therefore this wholesale removal with the hopes of spurring
people who care to come forward once again and work on a
coherent replacement.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/1326104915.2442.53.camel@twins
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Commit ad7687dde ("x86/numa: Check for nonsensical topologies on real
hw as well") is broken in that the condition can trigger for valid
setups but only changes the end result for invalid setups with no real
means of discerning between those.
Rewrite set_cpu_sibling_map() to make the code clearer and make sure
to only warn when the check changes the end result.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-klcwahu3gx467uhfiqjyhdcs@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Instead of only checking nonsensical topologies on numa-emu, do it
on real hardware as well, and print a warning.
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Tejun Heo <tj@kernel.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: x86@kernel.org
Link: http://lkml.kernel.org/n/tip-re15l0jqjtpz709oxozt2zoh@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When using numa=fake= you can get weird topologies where LLCs can span
nodes and other such nonsense. Cure this by hard partitioning these
masks on node boundaries.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Tejun Heo <tj@kernel.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: x86@kernel.org
Link: http://lkml.kernel.org/n/tip-di5vwjm96q5vrb76opwuflwx@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Added header for trampoline code that can be used to supply
input data to it. This makes interface between real mode code
and kernel cleaner and simpler. Replaced two confusing pointers
to level4 pgt in trampoline_64.S with a single pointer to the
beginning of the page table.
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@intel.com>
Link: http://lkml.kernel.org/r/1336501366-28617-21-git-send-email-jarkko.sakkinen@intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Migrated SMP trampoline code to the real mode blob.
SMP trampoline code is not yet removed from
.x86_trampoline because it is needed by the wakeup
code.
[ hpa: always enable compiling startup_32_smp in head_32.S... it is
only a few instructions which go into .init on UP builds, and it makes
the rest of the code less #ifdef ugly. ]
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@intel.com>
Link: http://lkml.kernel.org/r/1336501366-28617-6-git-send-email-jarkko.sakkinen@intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: x86@kernel.org
Link: http://lkml.kernel.org/r/20120420124557.246929343@linutronix.de
Preparatory patch to use the generic idle thread allocation.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: x86@kernel.org
Link: http://lkml.kernel.org/r/20120420124557.176604405@linutronix.de
Pull ACPI & Power Management changes from Len Brown:
- ACPI 5.0 after-ripples, ACPICA/Linux divergence cleanup
- cpuidle evolving, more ARM use
- thermal sub-system evolving, ditto
- assorted other PM bits
Fix up conflicts in various cpuidle implementations due to ARM cpuidle
cleanups (ARM at91 self-refresh and cpu idle code rewritten into
"standby" in asm conflicting with the consolidation of cpuidle time
keeping), trivial SH include file context conflict and RCU tracing fixes
in generic code.
* 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux: (77 commits)
ACPI throttling: fix endian bug in acpi_read_throttling_status()
Disable MCP limit exceeded messages from Intel IPS driver
ACPI video: Don't start video device until its associated input device has been allocated
ACPI video: Harden video bus adding.
ACPI: Add support for exposing BGRT data
ACPI: export acpi_kobj
ACPI: Fix logic for removing mappings in 'acpi_unmap'
CPER failed to handle generic error records with multiple sections
ACPI: Clean redundant codes in scan.c
ACPI: Fix unprotected smp_processor_id() in acpi_processor_cst_has_changed()
ACPI: consistently use should_use_kmap()
PNPACPI: Fix device ref leaking in acpi_pnp_match
ACPI: Fix use-after-free in acpi_map_lsapic
ACPI: processor_driver: add missing kfree
ACPI, APEI: Fix incorrect APEI register bit width check and usage
Update documentation for parameter *notrigger* in einj.txt
ACPI, APEI, EINJ, new parameter to control trigger action
ACPI, APEI, EINJ, limit the range of einj_param
ACPI, APEI, Fix ERST header length check
cpuidle: power_usage should be declared signed integer
...
Currently when a CPU is off-lined it enters either MWAIT-based idle or,
if MWAIT is not desired or supported, HLT-based idle (which places the
processor in C1 state). This patch allows processors without MWAIT
support to stay in states deeper than C1.
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@amd.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Pull scheduler fixes from Ingo Molnar.
* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
cpusets: Remove an unused variable
sched/rt: Improve pick_next_highest_task_rt()
sched: Fix select_fallback_rq() vs cpu_active/cpu_online
sched/x86/smp: Do not enable IRQs over calibrate_delay()
sched: Fix compiler warning about declared inline after use
MAINTAINERS: Update email address for SCHEDULER and PERF EVENTS
Pull kvm updates from Avi Kivity:
"Changes include timekeeping improvements, support for assigning host
PCI devices that share interrupt lines, s390 user-controlled guests, a
large ppc update, and random fixes."
This is with the sign-off's fixed, hopefully next merge window we won't
have rebased commits.
* 'kvm-updates/3.4' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (130 commits)
KVM: Convert intx_mask_lock to spin lock
KVM: x86: fix kvm_write_tsc() TSC matching thinko
x86: kvmclock: abstract save/restore sched_clock_state
KVM: nVMX: Fix erroneous exception bitmap check
KVM: Ignore the writes to MSR_K7_HWCR(3)
KVM: MMU: make use of ->root_level in reset_rsvds_bits_mask
KVM: PMU: add proper support for fixed counter 2
KVM: PMU: Fix raw event check
KVM: PMU: warn when pin control is set in eventsel msr
KVM: VMX: Fix delayed load of shared MSRs
KVM: use correct tlbs dirty type in cmpxchg
KVM: Allow host IRQ sharing for assigned PCI 2.3 devices
KVM: Ensure all vcpus are consistent with in-kernel irqchip settings
KVM: x86 emulator: Allow PM/VM86 switch during task switch
KVM: SVM: Fix CPL updates
KVM: x86 emulator: VM86 segments must have DPL 3
KVM: x86 emulator: Fix task switch privilege checks
arch/powerpc/kvm/book3s_hv.c: included linux/sched.h twice
KVM: x86 emulator: correctly mask pmc index bits in RDPMC instruction emulation
KVM: mmu_notifier: Flush TLBs before releasing mmu_lock
...
We should not ever enable IRQs until we're fully set up. This opens up
a window where interrupts can hit the cpu and interrupts can do
wakeups, wakeups need state that isn't set-up yet, in particular this
cpu isn't elegible to run tasks, so if any cpu-affine task that got
created in CPU_UP_PREPARE manages to get a wakeup, its affinity mask
will get broken and we'll run into lots of 'interesting' problems.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/n/tip-yaezmlbriluh166tfkgni22m@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull x86 platform changes from Ingo Molnar.
Removes the Moorestown platform that nobody ever used.
* 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/platform: Move APIC ID validity check into platform APIC code
x86/olpc/xo15/sci: Enable lid close wakeup control
x86/geode/net5501: Add platform driver for Soekris Engineering net5501
x86/geode/alix2: Supplement driver to include GPIO button support
x86/mid/powerbtn: Use MSIC read/write instead of ipc_scu
x86/mid/thermal: Turn off thermistor
x86/mid/thermal: Add msic_thermal alias
x86/mid/thermal: Convert to use Intel MSIC API
x86/mid/scu_ipc: Remove Moorestown support
x86/mid: Kill off Moorestown
x86/mrst: Add msic_thermal platform support
x86/config: Select MSIC MFD driver on Intel Medfield platform
x86/mid: Remove Intel Moorestown
x86/mrst: Set ISA bus type for fake MP IRQs
x86/ioapic: Use legacy_pic to set correct gsi-irq mapping
Pull trivial x86 branches from Ingo Molnar: small one-liners to fix up
details.
* 'x86-cpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86: Remove some noise from boot log when starting cpus
* 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86, boot: Fix port argument to inl() function
* 'x86-cpufeature-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86, cpufeature: Add CPU features from Intel document 319433-012A
* 'x86-process-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86_64: Record stack pointer before task execution begins
* 'x86-uv-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/UV: Lower UV rtc clocksource rating
Move APIC ID validity check into platform APIC code, so it can
be overridden when needed. For NumaChip systems, always trust
MADT, as it's constructed with high APIC IDs.
Behaviour verifies on standard x86 systems and on NumaChip
systems with this, and compile-tested with allyesconfig.
Signed-off-by: Daniel J Blueman <daniel@numascale-asia.com>
Reviewed-by: Steffen Persvold <sp@numascale.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: H. Peter Anvin <hpa@linux.intel.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Link: http://lkml.kernel.org/r/1331709454-27966-1-git-send-email-daniel@numascale-asia.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Stepan found:
CPU0 CPUn
_cpu_up()
__cpu_up()
boostrap()
notify_cpu_starting()
set_cpu_online()
while (!cpu_active())
cpu_relax()
<PREEMPT-out>
smp_call_function(.wait=1)
/* we find cpu_online() is true */
arch_send_call_function_ipi_mask()
/* wait-forever-more */
<PREEMPT-in>
local_irq_enable()
cpu_notify(CPU_ONLINE)
sched_cpu_active()
set_cpu_active()
Now the purpose of cpu_active is mostly with bringing down a cpu, where
we mark it !active to avoid the load-balancer from moving tasks to it
while we tear down the cpu. This is required because we only update the
sched_domain tree after we brought the cpu-down. And this is needed so
that some tasks can still run while we bring it down, we just don't want
new tasks to appear.
On cpu-up however the sched_domain tree doesn't yet include the new cpu,
so its invisible to the load-balancer, regardless of the active state.
So instead of setting the active state after we boot the new cpu (and
consequently having to wait for it before enabling interrupts) set the
cpu active before we set it online and avoid the whole mess.
Reported-by: Stepan Moskovchenko <stepanm@codeaurora.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1323965362.18942.71.camel@twins
Signed-off-by: Ingo Molnar <mingo@elte.hu>
When kvm guest uses kvmclock, it may hang on vcpu hot-plug.
This is caused by an overflow in pvclock_get_nsec_offset,
u64 delta = tsc - shadow->tsc_timestamp;
which in turn is caused by an undefined values from percpu
hv_clock that hasn't been initialized yet.
Uninitialized clock on being booted cpu is accessed from
start_secondary
-> smp_callin
-> smp_store_cpu_info
-> identify_secondary_cpu
-> mtrr_ap_init
-> mtrr_restore
-> stop_machine_from_inactive_cpu
-> queue_stop_cpus_work
...
-> sched_clock
-> kvm_clock_read
which is well before x86_cpuinit.setup_percpu_clockev call in
start_secondary, where percpu clock is initialized.
This patch introduces a hook that allows to setup/initialize
per_cpu clock early and avoid overflow due to reading
- undefined values
- old values if cpu was offlined and then onlined again
Another possible early user of this clock source is ftrace that
accesses it to get timestamps for ring buffer entries. So if
mtrr_ap_init is moved from identify_secondary_cpu to past
x86_cpuinit.setup_percpu_clockev in start_secondary, ftrace
may cause the same overflow/hang on cpu hot-plug anyway.
More complete description of the problem:
https://lkml.org/lkml/2012/2/2/101
Credits to Marcelo Tosatti <mtosatti@redhat.com> for hook idea.
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Printing the "start_ip" for every secondary cpu is very noisy on a large
system - and doesn't add any value. Drop this message.
Console log before:
Booting Node 0, Processors #1
smpboot cpu 1: start_ip = 96000
#2
smpboot cpu 2: start_ip = 96000
#3
smpboot cpu 3: start_ip = 96000
#4
smpboot cpu 4: start_ip = 96000
...
#31
smpboot cpu 31: start_ip = 96000
Brought up 32 CPUs
Console log after:
Booting Node 0, Processors #1#2#3#4#5#6#7 Ok.
Booting Node 1, Processors #8#9#10#11#12#13#14#15 Ok.
Booting Node 0, Processors #16#17#18#19#20#21#22#23 Ok.
Booting Node 1, Processors #24#25#26#27#28#29#30#31
Brought up 32 CPUs
Acked-by: Borislav Petkov <bp@amd64.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/4f452eb42507460426@agluck-desktop.sc.intel.com
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Found out that show_msr=<cpus> is broken, when I asked a
user to use it to capture debug info about broken MTRR's
whose MTRR settings are probably different between CPUs.
Only the first CPUs MSRs are printed, but that is not
enough to track down the suspected bug.
For years we called print_cpu_msr from print_cpu_info(),
but this commit:
| commit 2eaad1fddd
| Author: Mike Travis <travis@sgi.com>
| Date: Thu Dec 10 17:19:36 2009 -0800
|
| x86: Limit the number of processor bootup messages
removed the print_cpu_info() call from all APs.
Put it back - it will only print MSRs when the user
specifically requests them via show_msr=<cpus>.
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Mike Travis <travis@sgi.com>
Link: http://lkml.kernel.org/r/1329069237-11483-1-git-send-email-yinghai@kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/intel config: Fix the APB_TIMER selection
x86/mrst: Add additional debug prints for pb_keys
x86/intel config: Revamp configuration to allow for Moorestown and Medfield
x86/intel/scu/ipc: Match the changes in the x86 configuration
x86/apb: Fix configuration constraints
x86: Fix INTEL_MID silly
x86/Kconfig: Cyclone-timer depends on x86-summit
x86: Reduce clock calibration time during slave cpu startup
x86/config: Revamp configuration for MID devices
x86/sfi: Kill the IRQ as id hack
* 'x86-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86, reboot: Fix typo in nmi reboot path
x86, NMI: Add to_cpumask() to silence compile warning
x86, NMI: NMI selftest depends on the local apic
x86: Add stack top margin for stack overflow checking
x86, NMI: NMI-selftest should handle the UP case properly
x86: Fix the 32-bit stackoverflow-debug build
x86, NMI: Add knob to disable using NMI IPIs to stop cpus
x86, NMI: Add NMI IPI selftest
x86, reboot: Use NMI instead of REBOOT_VECTOR to stop cpus
x86: Clean up the range of stack overflow checking
x86: Panic on detection of stack overflow
x86: Check stack overflow in detail
If the x2apic mode is disabled for reasons like interrupt-remapping
not available etc, then we need to skip the logical cpu bringup of
apic-id's >= 255. Otherwise as the platform is in xapic mode, init/startup
IPI's will consider only the low 8-bits and there is a possibility of
re-sending init/startup IPI's to the logical cpu that is already online.
This will avoid potential reboots/unpredictable behavior etc.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Link: http://lkml.kernel.org/r/20111222014632.702932458@sbsiddha-desk.sc.intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Reduce the startup time for slave cpus.
Adds hooks for an arch-specific function for clock calibration.
These hooks are used on x86. If a newly started cpu has the
same phys_proc_id as a core already active, uses the TSC for the
delay loop and has a CONSTANT_TSC, use the already-calculated
value of loops_per_jiffy.
This patch reduces the time required to start slave cpus on a
4096 cpu system from: 465 sec OLD 62 sec NEW
This reduces boot time on a 4096p system by almost 7 minutes.
Nice...
Signed-off-by: Jack Steiner <steiner@sgi.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: John Stultz <john.stultz@linaro.org>
[fix CONFIG_SMP=n build]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The previous patch modified the stop cpus path to use NMI
instead of IRQ as the way to communicate to the other cpus to
shutdown. There were some concerns that various machines may
have problems with using an NMI IPI.
This patch creates a selftest to check if NMI is working at
boot. The idea is to help catch any issues before the machine
panics and we learn the hard way.
Loosely based on the locking-selftest.c file, this separate file
runs a couple of simple tests and reports the results. The
output looks like:
...
Brought up 4 CPUs
----------------
| NMI testsuite:
--------------------
remote IPI: ok |
local IPI: ok |
--------------------
Good, all 2 testcases passed! |
---------------------------------
Total of 4 processors activated (21330.61 BogoMIPS).
...
Signed-off-by: Don Zickus <dzickus@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Robert Richter <robert.richter@amd.com>
Cc: seiji.aguchi@hds.com
Cc: vgoyal@redhat.com
Cc: mjg@redhat.com
Cc: tony.luck@intel.com
Cc: gong.chen@intel.com
Cc: satoru.moriya@hds.com
Cc: avi@redhat.com
Cc: Andi Kleen <andi@firstfloor.org>
Link: http://lkml.kernel.org/r/1318533267-18880-3-git-send-email-dzickus@redhat.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86, smpboot: Mark the names[] array in __inquire_remote_apic() as const
x86: Convert vmalloc()+memset() to vzalloc()
After a newly plugged CPU sets the cpu_online bit it enables
interrupts and goes idle. The cpu which brought up the new cpu waits
for the cpu_online bit and when it observes it, it sets the cpu_active
bit for this cpu. The cpu_active bit is the relevant one for the
scheduler to consider the cpu as a viable target.
With forced threaded interrupt handlers which imply forced threaded
softirqs we observed the following race:
cpu 0 cpu 1
bringup(cpu1);
set_cpu_online(smp_processor_id(), true);
local_irq_enable();
while (!cpu_online(cpu1));
timer_interrupt()
-> wake_up(softirq_thread_cpu1);
-> enqueue_on(softirq_thread_cpu1, cpu0);
^^^^
cpu_notify(CPU_ONLINE, cpu1);
-> sched_cpu_active(cpu1)
-> set_cpu_active((cpu1, true);
When an interrupt happens before the cpu_active bit is set by the cpu
which brought up the newly onlined cpu, then the scheduler refuses to
enqueue the woken thread which is bound to that newly onlined cpu on
that newly onlined cpu due to the not yet set cpu_active bit and
selects a fallback runqueue. Not really an expected and desirable
behaviour.
So far this has only been observed with forced hard/softirq threading,
but in theory this could happen without forced threaded hard/softirqs
as well. It's probably unobservable as it would take a massive
interrupt storm on the newly onlined cpu which causes the softirq loop
to wake up the softirq thread and an even longer delay of the cpu
which waits for the cpu_online bit.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Peter Zijlstra <peterz@infradead.org>
Cc: stable@kernel.org # 2.6.39
A logic error in mwait_play_dead() causes the kernel to use
mwait even on cpus which don't support it, such as KVM virtual
cpus.
Introduced by:
349c004e3d31: x86: A fast way to check capabilities of the current cpu
Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=36222
Reported-by: Török Edwin <edwintorok@gmail.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/1306758237-9327-1-git-send-email-avi@redhat.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'idle-release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-idle-2.6:
x86 idle: deprecate mwait_idle() and "idle=mwait" cmdline param
x86 idle: deprecate "no-hlt" cmdline param
x86 idle APM: deprecate CONFIG_APM_CPU_IDLE
x86 idle floppy: deprecate disable_hlt()
x86 idle: EXPORT_SYMBOL(default_idle, pm_idle) only when APM demands it
x86 idle: clarify AMD erratum 400 workaround
idle governor: Avoid lock acquisition to read pm_qos before entering idle
cpuidle: menu: fixed wrapping timers at 4.294 seconds
The workaround for AMD erratum 400 uses the term "c1e" falsely suggesting:
1. Intel C1E is somehow involved
2. All AMD processors with C1E are involved
Use the string "amd_c1e" instead of simply "c1e" to clarify that
this workaround is specific to AMD's version of C1E.
Use the string "e400" to clarify that the workaround is specific
to AMD processors with Erratum 400.
This patch is text-substitution only, with no functional change.
cc: x86@kernel.org
Acked-by: Borislav Petkov <borislav.petkov@amd.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Add this_cpu_has() which determines if the current cpu has a certain
ability using a segment prefix and a bit test operation.
For that we need to add bit operations to x86s percpu.h.
Many uses of cpu_has use a pointer passed to a function to determine
the current flags. That is no longer necessary after this patch.
However, this patch only converts the straightforward cases where
cpu_has is used with this_cpu_ptr. The rest is work for later.
-tj: Rolled up patch to add x86_ prefix and use percpu_read() instead
of percpu_read_stable().
Signed-off-by: Christoph Lameter <cl@linux.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
* 'x86-trampoline-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86: Fix binutils-2.21 symbol related build failures
x86-64, trampoline: Remove unused variable
x86, reboot: Fix the use of passed arguments in 32-bit BIOS reboot
x86, reboot: Move the real-mode reboot code to an assembly file
x86: Make the GDT_ENTRY() macro in <asm/segment.h> safe for assembly
x86, trampoline: Use the unified trampoline setup for ACPI wakeup
x86, trampoline: Common infrastructure for low memory trampolines
Fix up trivial conflicts in arch/x86/kernel/Makefile
* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (93 commits)
x86, tlb, UV: Do small micro-optimization for native_flush_tlb_others()
x86-64, NUMA: Don't call numa_set_distanc() for all possible node combinations during emulation
x86-64, NUMA: Don't assume phys node 0 is always online in numa_emulation()
x86-64, NUMA: Clean up initmem_init()
x86-64, NUMA: Fix numa_emulation code with node0 without RAM
x86-64, NUMA: Revert NUMA affine page table allocation
x86: Work around old gas bug
x86-64, NUMA: Better explain numa_distance handling
x86-64, NUMA: Fix distance table handling
mm: Move early_node_map[] reverse scan helpers under HAVE_MEMBLOCK
x86-64, NUMA: Fix size of numa_distance array
x86: Rename e820_table_* to pgt_buf_*
bootmem: Move __alloc_memory_core_early() to nobootmem.c
bootmem: Move contig_page_data definition to bootmem.c/nobootmem.c
bootmem: Separate out CONFIG_NO_BOOTMEM code into nobootmem.c
x86-64, NUMA: Seperate out numa_alloc_distance() from numa_set_distance()
x86-64, NUMA: Add proper function comments to global functions
x86-64, NUMA: Move NUMA emulation into numa_emulation.c
x86-64, NUMA: Prepare numa_emulation() for moving NUMA emulation into a separate file
x86-64, NUMA: Do not scan two times for setup_node_bootmem()
...
Fix up conflicts in arch/x86/kernel/smpboot.c
Rusty Russell