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* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
perf, x86, nmi: Move LVT un-masking into irq handlers
perf events, x86: Work around the Nehalem AAJ80 erratum
perf, x86: Fix BTS condition
ftrace: Build without frame pointers on Microblaze
Extend the Intel Westmere PMU driver with definitions for generic front-end and
back-end stall events.
( These are only approximations. )
Reported-by: David Ahern <dsahern@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/n/tip-7y40wib8n008io7hjpn1dsrm@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Extend the Intel and AMD event definitions with generic front-end and
back-end stall events.
( These are only approximations - suggestions are welcome for better events. )
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/n/tip-7y40wib8n001io7hjpn1dsrm@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Add two generic hardware events: front-end and back-end stalled cycles.
These events measure conditions when the CPU is executing code but its
capabilities are not fully utilized. Understanding such situations and
analyzing them is an important sub-task of code optimization workflows.
Both events limit performance: most front end stalls tend to be caused
by branch misprediction or instruction fetch cachemisses, backend
stalls can be caused by various resource shortages or inefficient
instruction scheduling.
Front-end stalls are the more important ones: code cannot run fast
if the instruction stream is not being kept up.
An over-utilized back-end can cause front-end stalls and thus
has to be kept an eye on as well.
The exact composition is very program logic and instruction mix
dependent.
We use the terms 'stall', 'front-end' and 'back-end' loosely and
try to use the best available events from specific CPUs that
approximate these concepts.
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/n/tip-7y40wib8n000io7hjpn1dsrm@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Normally sys_rt_sigreturn() restores the old current->blocked which was
changed by handle_signal(), and unblocking is always fine.
But the debugger or application itself can change frame->uc_sigmask and
thus we need set_current_blocked()->retarget_shared_pending().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Matt Fleming <matt.fleming@linux.intel.com>
Acked-by: Tejun Heo <tj@kernel.org>
This is ugly, but if sigprocmask() needs retarget_shared_pending() then
handle signal should follow this logic. In theory it is newer correct to
add the new signals to current->blocked, the signal handler can sleep/etc
so we should notify other threads in case we block the pending signal and
nobody else has TIF_SIGPENDING.
Of course, this change doesn't make signals faster :/
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Matt Fleming <matt.fleming@linux.intel.com>
Acked-by: Tejun Heo <tj@kernel.org>
We use io_apic_setup_irq_pin() in order to configure pin's interrupt
number polarity and type. This is done on every irq_create_of_mapping()
which happens for instance during pci enable calls. Level typed
interrupts are masked by default, edge are unmasked.
On the first ->xlate() call the level interrupt is configured and
masked. The driver calls request_irq() and the line is unmasked. Lets
assume the interrupt line is shared with another device and we call
pci_enable_device() for this device. The ->xlate() configures the pin
again and it is masked. request_irq() does not unmask the line because
it _is_ already unmasked according to its internal state. So the
interrupt will never be unmasked again.
This patch is based on an earlier work by Torben Hohn and solves the
problem by configuring the pin only once. Since all devices must agree
on the same type and polarity there is no point in configuring the pin
more than once.
[ tglx: Split out the ce4100 part into a separate patch ]
Cc: Torben Hohn <torbenh@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: http://lkml.kernel.org/r/%3C20110427143052.GA15211%40linutronix.de%3E
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Use the UOPS_EXECUTED.*,c=1,i=1 event on Intel CPUs - it is a rather
good indicator of CPU execution stalls, more sensitive and more inclusive
than the 0xa2 resource stalls event (which does not count nearly as many
stall types).
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/n/tip-7y40wib8n1eqio7hjpn2dsrm@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
It was noticed that P4 machines were generating double NMIs for
each perf event. These extra NMIs lead to 'Dazed and confused'
messages on the screen.
I tracked this down to a P4 quirk that said the overflow bit had
to be cleared before re-enabling the apic LVT mask. My first
attempt was to move the un-masking inside the perf nmi handler
from before the chipset NMI handler to after.
This broke Nehalem boxes that seem to like the unmasking before
the counters themselves are re-enabled.
In order to keep this change simple for 2.6.39, I decided to
just simply move the apic LVT un-masking to the beginning of all
the chipset NMI handlers, with the exception of Pentium4's to
fix the double NMI issue.
Later on we can move the un-masking to later in the handlers to
save a number of 'extra' NMIs on those particular chipsets.
I tested this change on a P4 machine, an AMD machine, a Nehalem
box, and a core2quad box. 'perf top' worked correctly along
with various other small 'perf record' runs. Anything high
stress breaks all the machines but that is a different problem.
Thanks to various people for testing different versions of this
patch.
Reported-and-tested-by: Shaun Ruffell <sruffell@digium.com>
Signed-off-by: Don Zickus <dzickus@redhat.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Link: http://lkml.kernel.org/r/1303900353-10242-1-git-send-email-dzickus@redhat.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
CC: Cyrill Gorcunov <gorcunov@gmail.com>
Conflicts:
include/linux/perf_event.h
Merge reason: pick up the latest jump-label enhancements, they are cooked ready.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The new PERF_COUNT_HW_STALLED_CYCLES event tries to approximate
cycles the CPU does nothing useful, because it is stalled on a
cache-miss or some other condition.
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/n/tip-fue11vymwqsoo5to72jxxjyl@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
On Nehalem CPUs the retired branch-misses event can be completely bogus,
when there are no branch-misses occuring. When there are a lot of branch
misses then the count is pretty accurate. Still, this leaves us with an
event that over-counts a lot.
Detect this erratum and work it around by using BR_MISP_EXEC.ANY events.
These will also count speculated branches but still it's a lot more
precise in practice than the architectural event.
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/n/tip-yyfg0bxo9jsqxd6a0ovfny27@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Currently the x86 backend incorrectly assumes that any BRANCH_INSN
with sample_period==1 is a BTS request. This is not true when we do
frequency driven profiling such as 'perf record -e branches'.
Solves this error:
$ perf record -e branches ./array
Error: sys_perf_event_open() syscall returned with 95 (Operation not supported).
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reported-by: Ingo Molnar <mingo@elte.hu>
Cc: "Metzger, Markus T" <markus.t.metzger@intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/n/tip-rd2y4ct71hjawzz6fpvsy9hg@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
While the tracer accesses ptrace breakpoints, the child task may
concurrently exit due to a SIGKILL and thus release its breakpoints
at the same time. We can then dereference some freed pointers.
To fix this, hold a reference on the child breakpoints before
manipulating them.
Reported-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Prasad <prasad@linux.vnet.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: v2.6.33.. <stable@kernel.org>
Link: http://lkml.kernel.org/r/1302284067-7860-3-git-send-email-fweisbec@gmail.com
It's not enough to simply disable event on overflow the
cpuc->active_mask should be cleared as well otherwise counter
may stall in "active" even in real being already disabled (which
potentially may lead to the situation that user may not use this
counter further).
Don pointed out that:
" I also noticed this patch fixed some unknown NMIs
on a P4 when I stressed the box".
Tested-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Don Zickus <dzickus@redhat.com>
Signed-off-by: Don Zickus <dzickus@redhat.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Link: http://lkml.kernel.org/r/1303398203-2918-3-git-send-email-dzickus@redhat.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Andi Kleen pointed out that the Intel offcore support patches were merged
without user-space tool support to the functionality:
|
| The offcore_msr perf kernel code was merged into 2.6.39-rc*, but the
| user space bits were not. This made it impossible to set the extra mask
| and actually do the OFFCORE profiling
|
Andi submitted a preliminary patch for user-space support, as an
extension to perf's raw event syntax:
|
| Some raw events -- like the Intel OFFCORE events -- support additional
| parameters. These can be appended after a ':'.
|
| For example on a multi socket Intel Nehalem:
|
| perf stat -e r1b7:20ff -a sleep 1
|
| Profile the OFFCORE_RESPONSE.ANY_REQUEST with event mask REMOTE_DRAM_0
| that measures any access to DRAM on another socket.
|
But this kind of usability is absolutely unacceptable - users should not
be expected to type in magic, CPU and model specific incantations to get
access to useful hardware functionality.
The proper solution is to expose useful offcore functionality via
generalized events - that way users do not have to care which specific
CPU model they are using, they can use the conceptual event and not some
model specific quirky hexa number.
We already have such generalization in place for CPU cache events,
and it's all very extensible.
"Offcore" events measure general DRAM access patters along various
parameters. They are particularly useful in NUMA systems.
We want to support them via generalized DRAM events: either as the
fourth level of cache (after the last-level cache), or as a separate
generalization category.
That way user-space support would be very obvious, memory access
profiling could be done via self-explanatory commands like:
perf record -e dram ./myapp
perf record -e dram-remote ./myapp
... to measure DRAM accesses or more expensive cross-node NUMA DRAM
accesses.
These generalized events would work on all CPUs and architectures that
have comparable PMU features.
( Note, these are just examples: actual implementation could have more
sophistication and more parameter - as long as they center around
similarly simple usecases. )
Now we do not want to revert *all* of the current offcore bits, as they
are still somewhat useful for generic last-level-cache events, implemented
in this commit:
e994d7d23a0b: perf: Fix LLC-* events on Intel Nehalem/Westmere
But we definitely do not yet want to expose the unstructured raw events
to user-space, until better generalization and usability is implemented
for these hardware event features.
( Note: after generalization has been implemented raw offcore events can be
supported as well: there can always be an odd event that is marginally
useful but not useful enough to generalize. DRAM profiling is definitely
*not* such a category so generalization must be done first. )
Furthermore, PERF_TYPE_RAW access to these registers was not intended
to go upstream without proper support - it was a side-effect of the above
e994d7d23a0b commit, not mentioned in the changelog.
As v2.6.39 is nearing release we go for the simplest approach: disable
the PERF_TYPE_RAW offcore hack for now, before it escapes into a released
kernel and becomes an ABI.
Once proper structure is implemented for these hardware events and users
are offered usable solutions we can revisit this issue.
Reported-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1302658203-4239-1-git-send-email-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The default notifier doesn't make a lot of sense to call in the
correctable errors case. Drop it and emit the mcelog decoding
hint only in the uncorrectable errors case and when no notifier
is registered. Also, limit issuing the "mcelog --ascii" message
in the rare case when we dump unreported CEs before panicking.
While at it, remove unused old x86_mce_decode_callback from the
header.
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Nagananda Chumbalkar <Nagananda.Chumbalkar@hp.com>
Cc: Russ Anderson <rja@sgi.com>
Link: http://lkml.kernel.org/r/20110420102349.GB1361@aftab
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Andreas Herrmann reported that 7d6b46707f24 ("x86, NUMA: Fix fakenuma
boot failure") causes certain physical NUMA topologies (for example
AMD Magny-Cours) to move sibling cpus to a single node when in reality
they are in separate domains.
This may result in some nodes being completely void of cpus, which
doesn't accurately represent the correct topology. The system will
boot, but will have suboptimal NUMA performance.
This commit was intended as a fix for NUMA emulation, but should
not cause a regression for real NUMA machines as a side effect.
( There will be a separate fix for the numa-debug code, which
will not affect physical topologies. )
Reported-by: Andreas Herrmann <herrmann.der.user@googlemail.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/alpine.DEB.2.00.1104201918110.12634@chino.kir.corp.google.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Device suspend/resume infrastructure is used not only by the suspend
and hibernate code in kernel/power, but also by APM, Xen and the
kexec jump feature. However, commit 40dc166cb5dddbd36aa4ad11c03915ea
(PM / Core: Introduce struct syscore_ops for core subsystems PM)
failed to add syscore_suspend() and syscore_resume() calls to that
code, which generally leads to breakage when the features in question
are used.
To fix this problem, add the missing syscore_suspend() and
syscore_resume() calls to arch/x86/kernel/apm_32.c, kernel/kexec.c
and drivers/xen/manage.c.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86, gart: Make sure GART does not map physmem above 1TB
x86, gart: Set DISTLBWALKPRB bit always
x86, gart: Convert spaces to tabs in enable_gart_translation
* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
perf, x86: Fix AMD family 15h FPU event constraints
perf, x86: Fix pre-defined cache-misses event for AMD family 15h cpus
perf evsel: Fix use of inherit
perf hists browser: Fix seg fault when annotate null symbol
Correctable errors are considered something rather normal on
modern hardware these days. Even more importantly, correctable
errors mean exactly that - they've been corrected by the
hardware - and there's no need to taint the kernel since
execution hasn't been compromised so far.
Also, drop tainting in the thermal throttling code for a similar
reason: crossing a thermal threshold does not mean corruption.
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Acked-by: Tony Luck <tony.luck@intel.com>
Acked-by: Nagananda Chumbalkar <Nagananda.Chumbalkar@hp.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Russ Anderson <rja@sgi.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/1303135222-17118-1-git-send-email-bp@amd64.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
End users worry about the error interrupt printout we generate
currently:
pr_debug("APIC error on CPU%d: %02x(%02x)\n",
smp_processor_id(), v , v1);
... and would like to know the reason why error interrupts are generated.
This patch prints out more detailed debug information.
Another practical problem is that dynamic debug is not initialized yet
when the APIC initializes, so the pr_debug() will not output the error
interrupt debug information on bootup. In this patch, we use
apic_printk(APIC_DEBUG, ...), so the apic=debug boot option will print
verbose error interupts during bootup.
Signed-off-by: Youquan Song <youquan.song@intel.com>
Cc: Joe Perches <joe@perches.com>
Cc: hpa@linux.intel.com
Cc: suresh.b.siddha@intel.com
Cc: yong.y.wang@linux.intel.com
Cc: jbaron@redhat.com
Cc: trenn@suse.de
Cc: kent.liu@intel.com
Cc: chaohong.guo@intel.com
Link: http://lkml.kernel.org/r/1302762968-24380-2-git-send-email-youquan.song@intel.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Using ALTERNATIVE() when checking for X86_FEATURE_PERFCTR_CORE avoids
an extra pointer chase and data cache hit.
Signed-off-by: Robert Richter <robert.richter@amd.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1302913676-14352-4-git-send-email-robert.richter@amd.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Depending on the unit mask settings some FPU events may be scheduled
only on cpu counter #3. This patch fixes this.
Signed-off-by: Robert Richter <robert.richter@amd.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@googlemail.com>
Link: http://lkml.kernel.org/r/1302913676-14352-3-git-send-email-robert.richter@amd.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
With AMD cpu family 15h a unit mask was introduced for the Data Cache
Miss event (0x041/L1-dcache-load-misses). We need to enable bit 0
(first data cache miss or streaming store to a 64 B cache line) of
this mask to proper count data cache misses.
Now we set this bit for all families and models. In case a PMU does
not implement a unit mask for event 0x041 the bit is ignored.
Signed-off-by: Andre Przywara <andre.przywara@amd.com>
Signed-off-by: Robert Richter <robert.richter@amd.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1302913676-14352-2-git-send-email-robert.richter@amd.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Due to a decoder implementation quirk, some specific Intel CPUs
actually perform better with the "k8_nops" than with the
SDM-recommended NOPs. For runtime-selected NOPs, if we detect those
specific CPUs then use the k8_nops instead of the ones we would
normally use.
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jason Baron <jbaron@redhat.com>
Link: http://lkml.kernel.org/r/1303166160-10315-4-git-send-email-hpa@linux.intel.com
Clean up and unify the NOP selection infrastructure:
- Make the atomic 5-byte NOP a part of the selection system.
- Pick NOPs once during early boot and then be done with it.
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jason Baron <jbaron@redhat.com>
Link: http://lkml.kernel.org/r/1303166160-10315-3-git-send-email-hpa@linux.intel.com
This patch changes the allocation of the GART aperture to
enforce only natural alignment instead of aligning it on
512MB. This big alignment was used to force the GART
aperture to be over 512MB. This is enforced by using 512MB
as the lower-bound address in the allocation range.
[ hpa: The actual number 512 MiB needs to be revisited, too. ]
Cc: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Link: http://lkml.kernel.org/r/1303134346-5805-2-git-send-email-joerg.roedel@amd.com
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
The GART can only map physical memory below 1TB. Make sure
the gart driver in the kernel does not try to map memory
above 1TB.
Cc: <stable@kernel.org>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Link: http://lkml.kernel.org/r/1303134346-5805-5-git-send-email-joerg.roedel@amd.com
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
The DISTLBWALKPRB bit must be set for the GART because the
gatt table is mapped UC. But the current code does not set
the bit at boot when the BIOS setup the aperture correctly.
Fix that by setting this bit when enabling the GART instead
of the other places.
Cc: <stable@kernel.org>
Cc: Borislav Petkov <borislav.petkov@amd.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Link: http://lkml.kernel.org/r/1303134346-5805-4-git-send-email-joerg.roedel@amd.com
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
This patch disables GartTlbWlk errors on AMD Fam10h CPUs if
the BIOS forgets to do is (or is just too old). Letting
these errors enabled can cause a sync-flood on the CPU
causing a reboot.
The AMD BKDG recommends disabling GART TLB Wlk Error completely.
This patch is the fix for
https://bugzilla.kernel.org/show_bug.cgi?id=33012
on my machine.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Link: http://lkml.kernel.org/r/20110415131152.GJ18463@8bytes.org
Tested-by: Alexandre Demers <alexandre.f.demers@gmail.com>
Cc: <stable@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Currently, numa=fake boot parameter is broken. If it's used,
kernel may panic due to devide by zero error depending on CPU
configuration
Call Trace:
[<ffffffff8104ad4c>] find_busiest_group+0x38c/0xd30
[<ffffffff81086aff>] ? local_clock+0x6f/0x80
[<ffffffff81050533>] load_balance+0xa3/0x600
[<ffffffff81050f53>] idle_balance+0xf3/0x180
[<ffffffff81550092>] schedule+0x722/0x7d0
[<ffffffff81550538>] ? wait_for_common+0x128/0x190
[<ffffffff81550a65>] schedule_timeout+0x265/0x320
[<ffffffff81095815>] ? lock_release_holdtime+0x35/0x1a0
[<ffffffff81550538>] ? wait_for_common+0x128/0x190
[<ffffffff8109bb6c>] ? __lock_release+0x9c/0x1d0
[<ffffffff815534e0>] ? _raw_spin_unlock_irq+0x30/0x40
[<ffffffff815534e0>] ? _raw_spin_unlock_irq+0x30/0x40
[<ffffffff81550540>] wait_for_common+0x130/0x190
[<ffffffff81051920>] ? try_to_wake_up+0x510/0x510
[<ffffffff8155067d>] wait_for_completion+0x1d/0x20
[<ffffffff8107f36c>] kthread_create_on_node+0xac/0x150
[<ffffffff81077bb0>] ? process_scheduled_works+0x40/0x40
[<ffffffff8155045f>] ? wait_for_common+0x4f/0x190
[<ffffffff8107a283>] __alloc_workqueue_key+0x1a3/0x590
[<ffffffff81e0cce2>] cpuset_init_smp+0x6b/0x7b
[<ffffffff81df3d07>] kernel_init+0xc3/0x182
[<ffffffff8155d5e4>] kernel_thread_helper+0x4/0x10
[<ffffffff81553cd4>] ? retint_restore_args+0x13/0x13
[<ffffffff81df3c44>] ? start_kernel+0x400/0x400
[<ffffffff8155d5e0>] ? gs_change+0x13/0x13
The divede by zero is caused by the following line,
group->cpu_power==0:
kernel/sched_fair.c::update_sg_lb_stats()
/* Adjust by relative CPU power of the group */
sgs->avg_load = (sgs->group_load * SCHED_LOAD_SCALE) / group->cpu_power;
This regression was caused by commit e23bba6044 ("x86-64, NUMA: Unify
emulated distance mapping") because it changes cpu -> node
mapping in the process of dropping fake_physnodes().
old) all cpus are assinged node 0
now) cpus are assigned round robin
(the logic is implemented by numa_init_array())
Note: The change in behavior only happens if the system doesn't
have neither ACPI SRAT table nor AMD northbridge NUMA
information.
Round robin assignment doesn't work because init_numa_sched_groups_power()
assumes all logical cpus in the same physical cpu share the same node
(then it only accounts for group_first_cpu()), and the simple round robin
breaks the above assumption.
Thus, this patch implements a reassignment of node-ids if buggy firmware
or numa emulation makes wrong cpu node map. Tt enforce all logical cpus
in the same physical cpu share the same node.
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Shaohui Zheng <shaohui.zheng@intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: H. Peter Anvin <hpa@linux.intel.com>
Link: http://lkml.kernel.org/r/20110415203928.1303.A69D9226@jp.fujitsu.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
For future rework of try_to_wake_up() we'd like to push part of that
function onto the CPU the task is actually going to run on.
In order to do so we need a generic callback from the existing scheduler IPI.
This patch introduces such a generic callback: scheduler_ipi() and
implements it as a NOP.
BenH notes: PowerPC might use this IPI on offline CPUs under rare conditions!
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Acked-by: Chris Metcalf <cmetcalf@tilera.com>
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Reviewed-by: Frank Rowand <frank.rowand@am.sony.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20110405152728.744338123@chello.nl
This patch adds detection of the extended features of an
AMD IOMMU. The available features are printed to dmesg on
boot.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
This patch adds the necessary code to the AMD IOMMU driver
for enabling and disabling the ATS capability on a device
and to setup the IOMMU data structures correctly.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
This patch adds a flag to the AMD IOMMU driver to indicate
that all IOMMUs present in the system support device IOTLBs.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
This patch implements a function to flush the IOTLB on
devices supporting ATS and makes sure that this TLB is also
flushed if necessary.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Currently the option resides under X86_EXTENDED_PLATFORM due to historical
nonstandard A20M# handling. However that is no longer the case and so Elan can
be treated as part of the standard processor choice Kconfig option.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Link: http://lkml.kernel.org/r/1302245177.31620.47.camel@localhost.localdomain
Cc: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
