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2014-06-05locking/mutexes: Documentation update/rewriteDavidlohr Bueso
Our mutexes have gone a long ways since the original implementation back in 2005/2006. However, the mutex-design.txt document is still stuck in the past, to the point where most of the information there is practically useless and, more important, simply incorrect. This patch pretty much rewrites it to resemble what we have nowadays. Since regular semaphores are almost much extinct in the kernel (most users now rely on mutexes or rwsems), it no longer makes sense to have such a close comparison, which was copied from most of the cover letter when Ingo introduced the generic mutex subsystem. Note that ww_mutexes are intentionally left out, leaving things as generic as possible. Signed-off-by: Davidlohr Bueso <davidlohr@hp.com> Cc: tim.c.chen@linux.intel.com Cc: paulmck@linux.vnet.ibm.com Cc: waiman.long@hp.com Cc: jason.low2@hp.com Cc: aswin@hp.com Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1401338203.2618.11.camel@buesod1.americas.hpqcorp.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-06-05microblaze: Fix typo in head.S s/substract/subtract/Antonio Ospite
Signed-off-by: Antonio Ospite <ao2@ao2.it> Cc: Michal Simek <monstr@monstr.eu> Cc: "Edgar E. Iglesias" <edgar.iglesias@gmail.com> Signed-off-by: Michal Simek <michal.simek@xilinx.com>
2014-06-05perf/documentation: Add description for conditional branch filterAnshuman Khandual
Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com> Reviewed-by: Stephane Eranian <eranian@google.com> Reviewed-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: mpe@ellerman.id.au Cc: benh@kernel.crashing.org Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1400743210-32289-4-git-send-email-khandual@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-06-05perf/x86: Add conditional branch filtering supportAnshuman Khandual
This patch adds conditional branch filtering support, enabling it for PERF_SAMPLE_BRANCH_COND in perf branch stack sampling framework by utilizing an available software filter X86_BR_JCC. Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com> Reviewed-by: Stephane Eranian <eranian@google.com> Reviewed-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: mpe@ellerman.id.au Cc: benh@kernel.crashing.org Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1400743210-32289-3-git-send-email-khandual@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-06-05perf/tool: Add conditional branch filter 'cond' to perf recordAnshuman Khandual
Adding perf record support for new branch stack filter criteria PERF_SAMPLE_BRANCH_COND. Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com> Reviewed-by: Stephane Eranian <eranian@google.com> Reviewed-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1400743210-32289-2-git-send-email-khandual@linux.vnet.ibm.com Cc: mpe@ellerman.id.au Cc: benh@kernel.crashing.org Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-06-05perf: Add new conditional branch filter 'PERF_SAMPLE_BRANCH_COND'Anshuman Khandual
This patch introduces new branch filter PERF_SAMPLE_BRANCH_COND which will extend the existing perf ABI. This will filter branches which are conditional. Various architectures can provide this functionality either with HW filtering support (if present) or with SW filtering of captured branch instructions. Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com> Reviewed-by: Stephane Eranian <eranian@google.com> Reviewed-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: mpe@ellerman.id.au Cc: benh@kernel.crashing.org Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1400743210-32289-1-git-send-email-khandual@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-06-05uprobes: Teach copy_insn() to support tmpfsOleg Nesterov
tmpfs is widely used but as Denys reports shmem_aops doesn't have ->readpage() and thus you can't probe a binary on this filesystem. As Hugh suggested we can use shmem_read_mapping_page() in this case, just we need to check shmem_mapping() if ->readpage == NULL. Reported-by: Denys Vlasenko <dvlasenk@redhat.com> Suggested-by: Hugh Dickins <hughd@google.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20140519184136.GB6750@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-06-05uprobes: Shift ->readpage check from __copy_insn() to uprobe_register()Oleg Nesterov
copy_insn() fails with -EIO if ->readpage == NULL, but this error is not propagated unless uprobe_register() path finds ->mm which already mmaps this file. In this case (say) "perf record" does not actually install the probe, but the user can't know about this. Move this check into uprobe_register() so that this problem can be detected earlier and reported to user. Note: this is still not perfect, - copy_insn() and arch_uprobe_analyze_insn() should be called by uprobe_register() but this is not simple, we need vm_file for read_mapping_page() (although perhaps we can pass NULL), and we need ->mm for is_64bit_mm() (although this logic is broken anyway). - uprobe_register() should be called by create_trace_uprobe(), not by probe_event_enable(), so that an error can be detected at "perf probe -x" time. This also needs more changes in the core uprobe code, uprobe register/unregister interface was poorly designed from the very beginning. Reported-by: Denys Vlasenko <dvlasenk@redhat.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Hugh Dickins <hughd@google.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20140519184054.GA6750@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-06-05perf/x86: Use common PMU interrupt disabled codeVince Weaver
Make the x86 perf code use the new common PMU interrupt disabled code. Typically most x86 machines have working PMU interrupts, although some older p6-class machines had this problem. Signed-off-by: Vince Weaver <vincent.weaver@maine.edu> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1405161715560.11099@vincent-weaver-1.umelst.maine.edu Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-06-05perf/ARM: Use common PMU interrupt disabled codeVince Weaver
Make the ARM perf code use the new common PMU interrupt disabled code. This allows perf to work on ARM machines without a working PMU interrupt (for example, raspberry pi). Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Vince Weaver <vincent.weaver@maine.edu> [peterz: applied changes suggested by Will] Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Grant Likely <grant.likely@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Rob Herring <robh+dt@kernel.org> Cc: Russell King <linux@arm.linux.org.uk> Cc: Will Deacon <will.deacon@arm.com> Cc: devicetree@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1405161712190.11099@vincent-weaver-1.umelst.maine.edu [ Small readability tweaks to the code. ] Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-06-05perf: Disable sampled events if no PMU interruptVince Weaver
Add common code to generate -ENOTSUPP at event creation time if an architecture attempts to create a sampled event and PERF_PMU_NO_INTERRUPT is set. This adds a new pmu->capabilities flag. Initially we only support PERF_PMU_NO_INTERRUPT (to indicate a PMU has no support for generating hardware interrupts) but there are other capabilities that can be added later. Signed-off-by: Vince Weaver <vincent.weaver@maine.edu> Acked-by: Will Deacon <will.deacon@arm.com> [peterz: rename to PERF_PMU_CAP_* and moved the pmu::capabilities word into a hole] Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1405161708060.11099@vincent-weaver-1.umelst.maine.edu Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-06-05perf: Fix use after free in perf_remove_from_context()Peter Zijlstra
While that mutex should guard the elements, it doesn't guard against the use-after-free that's from list_for_each_entry_rcu(). __perf_event_exit_task() can actually free the event. And because list addition/deletion is guarded by both ctx->mutex and ctx->lock, holding ctx->mutex is sufficient for reading the list, so we don't actually need the rcu list iteration. Fixes: 3a497f48637e ("perf: Simplify perf_event_exit_task_context()") Reported-by: Sasha Levin <sasha.levin@oracle.com> Tested-by: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Dave Jones <davej@redhat.com> Cc: acme@ghostprotocols.net Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20140529170024.GA2315@laptop.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-06-05Merge commit '9e9a928eed8796a0a1aaed7e0b676db86ba84594' into drm-nextDave Airlie
Merge drm-fixes into drm-next. Both i915 and radeon need this done for later patches. Conflicts: drivers/gpu/drm/drm_crtc_helper.c drivers/gpu/drm/i915/i915_drv.h drivers/gpu/drm/i915/i915_gem.c drivers/gpu/drm/i915/i915_gem_execbuffer.c drivers/gpu/drm/i915/i915_gem_gtt.c
2014-06-05Merge branch 'perf/kprobes' into perf/coreIngo Molnar
Conflicts: arch/x86/kernel/traps.c The kprobes enhancements are fully cooked, ship them upstream. Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-06-05Merge branch 'perf/uprobes' into perf/coreIngo Molnar
These bits from Oleg are fully cooked, ship them to Linus. Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-06-05sched/idle: Optimize try-to-wake-up IPIPeter Zijlstra
[ This series reduces the number of IPIs on Andy's workload by something like 99%. It's down from many hundreds per second to very few. The basic idea behind this series is to make TIF_POLLING_NRFLAG be a reliable indication that the idle task is polling. Once that's done, the rest is reasonably straightforward. ] When enqueueing tasks on remote LLC domains, we send an IPI to do the work 'locally' and avoid bouncing all the cachelines over. However, when the remote CPU is idle (and polling, say x86 mwait), we don't need to send an IPI, we can simply kick the TIF word to wake it up and have the 'idle' loop do the work. So when _TIF_POLLING_NRFLAG is set, but _TIF_NEED_RESCHED is not (yet) set, set _TIF_NEED_RESCHED and avoid sending the IPI. Much-requested-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Peter Zijlstra <peterz@infradead.org> [Edited by Andy Lutomirski, but this is mostly Peter Zijlstra's code.] Signed-off-by: Andy Lutomirski <luto@amacapital.net> Cc: nicolas.pitre@linaro.org Cc: daniel.lezcano@linaro.org Cc: Mike Galbraith <umgwanakikbuti@gmail.com> Cc: umgwanakikbuti@gmail.com Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/ce06f8b02e7e337be63e97597fc4b248d3aa6f9b.1401902905.git.luto@amacapital.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-06-05sched/idle: Simplify wake_up_idle_cpu()Andy Lutomirski
Now that rq->idle's polling bit is a reliable indication that the cpu is polling, use it. Signed-off-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: nicolas.pitre@linaro.org Cc: daniel.lezcano@linaro.org Cc: umgwanakikbuti@gmail.com Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/922f00761445a830ebb23d058e2ae53956ce2d73.1401902905.git.luto@amacapital.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-06-05sched/idle: Clear polling before descheduling the idle threadAndy Lutomirski
Currently, the only real guarantee provided by the polling bit is that, if you hold rq->lock and the polling bit is set, then you can set need_resched to force a reschedule. The only reason the lock is needed is that the idle thread might not be running at all when setting its need_resched bit, and rq->lock keeps it pinned. This is easy to fix: just clear the polling bit before scheduling. Now the idle thread's polling bit is only ever set when rq->curr == rq->idle. Signed-off-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: nicolas.pitre@linaro.org Cc: daniel.lezcano@linaro.org Cc: umgwanakikbuti@gmail.com Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/b2059fcb4c613d520cb503b6fad6e47033c7c203.1401902905.git.luto@amacapital.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-06-05sched, trace: Add a tracepoint for IPI-less remote wakeupsAndy Lutomirski
Remote wakeups of polling CPUs are a valuable performance improvement; add a tracepoint to make it much easier to verify that they're working. Signed-off-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: nicolas.pitre@linaro.org Cc: daniel.lezcano@linaro.org Cc: umgwanakikbuti@gmail.com Cc: David Ahern <dsahern@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/16205aee116772aa686814f9b13bccb562108047.1401902905.git.luto@amacapital.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-06-05cpuidle: Set polling in poll_idleAndy Lutomirski
poll_idle is the archetypal polling idle loop; tell the core idle code about it. This avoids pointless IPIs when all of the other cpuidle states are disabled. Signed-off-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: nicolas.pitre@linaro.org Cc: umgwanakikbuti@gmail.com Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Rafael J. Wysocki <rjw@rjwysocki.net> Cc: linux-kernel@vger.kernel.org Cc: linux-pm@vger.kernel.org Link: http://lkml.kernel.org/r/c65ce49615d338bae8fb79df5daffab19353c900.1401902905.git.luto@amacapital.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-06-05i40e: add missing VSI statisticsShannon Nelson
Add a couple more statistics that the hardware offers but aren't part of the standard netdev stats. Change-ID: I201db2898f2c284aee3d9631470bc5edd349e9a5 Signed-off-by: Shannon Nelson <shannon.nelson@intel.com> Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
2014-06-05sched: Remove redundant assignment to "rt_rq" in update_curr_rt(...)Giedrius Rekasius
Variable "rt_rq" is used only in block "for_each_sched_rt_entity" so the value assigned to it at the beginning of the update_curr_rt(...) gets overwritten without ever being read. Remove redundant assignment and move variable declaration to the block in which it is being used. Signed-off-by: Giedrius Rekasius <giedrius.rekasius@gmail.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: kernel-janitors@vger.kernel.org Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/1401027811-30066-1-git-send-email-giedrius.rekasius@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-06-05sched: Rename capacity related flagsNicolas Pitre
It is better not to think about compute capacity as being equivalent to "CPU power". The upcoming "power aware" scheduler work may create confusion with the notion of energy consumption if "power" is used too liberally. Let's rename the following feature flags since they do relate to capacity: SD_SHARE_CPUPOWER -> SD_SHARE_CPUCAPACITY ARCH_POWER -> ARCH_CAPACITY NONTASK_POWER -> NONTASK_CAPACITY Signed-off-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Morten Rasmussen <morten.rasmussen@arm.com> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: linaro-kernel@lists.linaro.org Cc: Andy Fleming <afleming@freescale.com> Cc: Anton Blanchard <anton@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Grant Likely <grant.likely@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com> Cc: Rob Herring <robh+dt@kernel.org> Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Cc: Toshi Kani <toshi.kani@hp.com> Cc: Vasant Hegde <hegdevasant@linux.vnet.ibm.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: devicetree@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: linuxppc-dev@lists.ozlabs.org Link: http://lkml.kernel.org/n/tip-e93lpnxb87owfievqatey6b5@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-06-05sched: Final power vs. capacity cleanupsNicolas Pitre
It is better not to think about compute capacity as being equivalent to "CPU power". The upcoming "power aware" scheduler work may create confusion with the notion of energy consumption if "power" is used too liberally. This contains the architecture visible changes. Incidentally, only ARM takes advantage of the available pow^H^H^Hcapacity scaling hooks and therefore those changes outside kernel/sched/ are confined to one ARM specific file. The default arch_scale_smt_power() hook is not overridden by anyone. Replacements are as follows: arch_scale_freq_power --> arch_scale_freq_capacity arch_scale_smt_power --> arch_scale_smt_capacity SCHED_POWER_SCALE --> SCHED_CAPACITY_SCALE SCHED_POWER_SHIFT --> SCHED_CAPACITY_SHIFT The local usage of "power" in arch/arm/kernel/topology.c is also changed to "capacity" as appropriate. Signed-off-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Morten Rasmussen <morten.rasmussen@arm.com> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: linaro-kernel@lists.linaro.org Cc: Arnd Bergmann <arnd@arndb.de> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> Cc: Grant Likely <grant.likely@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mark Brown <broonie@linaro.org> Cc: Rob Herring <robh+dt@kernel.org> Cc: Russell King <linux@arm.linux.org.uk> Cc: Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: devicetree@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/n/tip-48zba9qbznvglwelgq2cfygh@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-06-05sched: Remove remaining dubious usage of "power"Nicolas Pitre
It is better not to think about compute capacity as being equivalent to "CPU power". The upcoming "power aware" scheduler work may create confusion with the notion of energy consumption if "power" is used too liberally. This is the remaining "power" -> "capacity" rename for local symbols. Those symbols visible to the rest of the kernel are not included yet. Signed-off-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Morten Rasmussen <morten.rasmussen@arm.com> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: linaro-kernel@lists.linaro.org Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/n/tip-yyyhohzhkwnaotr3lx8zd5aa@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-06-05sched: Let 'struct sched_group_power' care about CPU capacityNicolas Pitre
It is better not to think about compute capacity as being equivalent to "CPU power". The upcoming "power aware" scheduler work may create confusion with the notion of energy consumption if "power" is used too liberally. Since struct sched_group_power is really about compute capacity of sched groups, let's rename it to struct sched_group_capacity. Similarly sgp becomes sgc. Related variables and functions dealing with groups are also adjusted accordingly. Signed-off-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Morten Rasmussen <morten.rasmussen@arm.com> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: linaro-kernel@lists.linaro.org Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/n/tip-5yeix833vvgf2uyj5o36hpu9@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-06-05sched/fair: Disambiguate existing/remaining "capacity" usageNicolas Pitre
We have "power" (which should actually become "capacity") and "capacity" which is a scaled down "capacity factor" in terms of unitary tasks. Let's use "capacity_factor" to make room for proper usage of "capacity" later. Signed-off-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Morten Rasmussen <morten.rasmussen@arm.com> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: linaro-kernel@lists.linaro.org Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/n/tip-gk1co8sqdev3763opqm6ovml@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-06-05sched/fair: Change "has_capacity" to "has_free_capacity"Nicolas Pitre
The capacity of a CPU/group should be some intrinsic value that doesn't change with task placement. It is like a container which capacity is stable regardless of the amount of liquid in it (its "utilization")... unless the container itself is crushed that is, but that's another story. Therefore let's rename "has_capacity" to "has_free_capacity" in order to better convey the wanted meaning. Signed-off-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Morten Rasmussen <morten.rasmussen@arm.com> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: linaro-kernel@lists.linaro.org Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/n/tip-djzkk027jm0e8x8jxy70opzh@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-06-05sched/fair: Remove "power" from 'struct numa_stats'Nicolas Pitre
It is better not to think about compute capacity as being equivalent to "CPU power". The upcoming "power aware" scheduler work may create confusion with the notion of energy consumption if "power" is used too liberally. To make things explicit and not create more confusion with the existing "capacity" member, let's rename things as follows: power -> compute_capacity capacity -> task_capacity Note: none of those fields are actually used outside update_numa_stats(). Signed-off-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Morten Rasmussen <morten.rasmussen@arm.com> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: linaro-kernel@lists.linaro.org Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/n/tip-2e2ndymj5gyshyjq8am79f20@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-06-05sched: Fix signedness bug in yield_to()Dan Carpenter
yield_to() is supposed to return -ESRCH if there is no task to yield to, but because the type is bool that is the same as returning true. The only place I see which cares is kvm_vcpu_on_spin(). Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Reviewed-by: Raghavendra <raghavendra.kt@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Gleb Natapov <gleb@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: kvm@vger.kernel.org Link: http://lkml.kernel.org/r/20140523102042.GA7267@mwanda Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-06-05sched/fair: Use time_after() in record_wakee()Manuel Schölling
To be future-proof and for better readability the time comparisons are modified to use time_after() instead of plain, error-prone math. Signed-off-by: Manuel Schölling <manuel.schoelling@gmx.de> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1400780723-24626-1-git-send-email-manuel.schoelling@gmx.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-06-05sched/balancing: Reduce the rate of needless idle load balancingTim Chen
The current no_hz idle load balancer do load balancing for *all* idle cpus, even though the time due to load balance for a particular idle cpu could be still a while in the future. This introduces a much higher load balancing rate than what is necessary. The patch changes the behavior by only doing idle load balancing on behalf of an idle cpu only when it is due for load balancing. On SGI's systems with over 3000 cores, the cpu responsible for idle balancing got overwhelmed with idle balancing, and introduces a lot of OS noise to workloads. This patch fixes the issue. Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com> Acked-by: Russ Anderson <rja@sgi.com> Reviewed-by: Rik van Riel <riel@redhat.com> Reviewed-by: Jason Low <jason.low2@hp.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Len Brown <len.brown@intel.com> Cc: Dimitri Sivanich <sivanich@sgi.com> Cc: Hedi Berriche <hedi@sgi.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: MichelLespinasse <walken@google.com> Cc: Peter Hurley <peter@hurleysoftware.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1400621967.2970.280.camel@schen9-DESK Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-06-05sched/fair: Fix unlocked reads of some cfs_b->quota/periodBen Segall
sched_cfs_period_timer() reads cfs_b->period without locks before calling do_sched_cfs_period_timer(), and similarly unthrottle_offline_cfs_rqs() would read cfs_b->period without the right lock. Thus a simultaneous change of bandwidth could cause corruption on any platform where ktime_t or u64 writes/reads are not atomic. Extend cfs_b->lock from do_sched_cfs_period_timer() to include the read of cfs_b->period to solve that issue; unthrottle_offline_cfs_rqs() can just use 1 rather than the exact quota, much like distribute_cfs_runtime() does. There is also an unlocked read of cfs_b->runtime_expires, but a race there would only delay runtime expiry by a tick. Still, the comparison should just be != anyway, which clarifies even that problem. Signed-off-by: Ben Segall <bsegall@google.com> Tested-by: Roman Gushchin <klamm@yandex-team.ru> [peterz: Fix compile warn] Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20140519224945.20303.93530.stgit@sword-of-the-dawn.mtv.corp.google.com Cc: pjt@google.com Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-06-05sched/fair: Fix tg_set_cfs_bandwidth() deadlock on rq->lockRoman Gushchin
tg_set_cfs_bandwidth() sets cfs_b->timer_active to 0 to force the period timer restart. It's not safe, because can lead to deadlock, described in commit 927b54fccbf0: "__start_cfs_bandwidth calls hrtimer_cancel while holding rq->lock, waiting for the hrtimer to finish. However, if sched_cfs_period_timer runs for another loop iteration, the hrtimer can attempt to take rq->lock, resulting in deadlock." Three CPUs must be involved: CPU0 CPU1 CPU2 take rq->lock period timer fired ... take cfs_b lock ... ... tg_set_cfs_bandwidth() throttle_cfs_rq() release cfs_b lock take cfs_b lock ... distribute_cfs_runtime() timer_active = 0 take cfs_b->lock wait for rq->lock ... __start_cfs_bandwidth() {wait for timer callback break if timer_active == 1} So, CPU0 and CPU1 are deadlocked. Instead of resetting cfs_b->timer_active, tg_set_cfs_bandwidth can wait for period timer callbacks (ignoring cfs_b->timer_active) and restart the timer explicitly. Signed-off-by: Roman Gushchin <klamm@yandex-team.ru> Reviewed-by: Ben Segall <bsegall@google.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/87wqdi9g8e.wl\%klamm@yandex-team.ru Cc: pjt@google.com Cc: chris.j.arges@canonical.com Cc: gregkh@linuxfoundation.org Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-06-05sched/dl: Fix race in dl_task_timer()Kirill Tkhai
Throttled task is still on rq, and it may be moved to other cpu if user is playing with sched_setaffinity(). Therefore, unlocked task_rq() access makes the race. Juri Lelli reports he got this race when dl_bandwidth_enabled() was not set. Other thing, pointed by Peter Zijlstra: "Now I suppose the problem can still actually happen when you change the root domain and trigger a effective affinity change that way". To fix that we do the same as made in __task_rq_lock(). We do not use __task_rq_lock() itself, because it has a useful lockdep check, which is not correct in case of dl_task_timer(). We do not need pi_lock locked here. This case is an exception (PeterZ): "The only reason we don't strictly need ->pi_lock now is because we're guaranteed to have p->state == TASK_RUNNING here and are thus free of ttwu races". Signed-off-by: Kirill Tkhai <tkhai@yandex.ru> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: <stable@vger.kernel.org> # v3.14+ Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/3056991400578422@web14g.yandex.ru Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-06-05i40e/i40evf: remove rx_errors and rx_missedShannon Nelson
The rx_errors (GLV_REPC) and rx_missed (GLV_RMPC) were removed from the chip design. Change-ID: Ifdeb69c90feac64ec95c36d3d32c75e3a06de3b7 Signed-off-by: Shannon Nelson <shannon.nelson@intel.com> Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
2014-06-05i40e: refactor stats collectionShannon Nelson
Pull the PF stat collection out of the VSI collection routine, and add a unifying stats update routine to call the various stat collection routines. Change-ID: I224192455bb3a6e5dc0a426935e67dffc123e306 Signed-off-by: Shannon Nelson <shannon.nelson@intel.com> Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
2014-06-05i40e: refactor send versionJesse Brandeburg
This change moves some common code in two places into a small helper function, and corrects a bug in one of the two places in the process. Change-ID: If3bba7152b240f13a7881eb0e8a781655fa66ce7 Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com> Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
2014-06-05i40e/i40evf: VEB structure added, GTIME macro updateKamil Krawczyk
Structure for VEB context added. Update macro for transition from ms to GTIME (us) time units. Change-ID: Ib3a19587b4cf355348655df8f60c6f37bb1497a3 Signed-off-by: Kamil Krawczyk <kamil.krawczyk@intel.com> Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
2014-06-05i40e: notify VF of all types of resetsMitch Williams
Currently, the PF driver only notifies the VFs for PF reset events. Instead, notify the VFs for all types of resets, so they can attempt a graceful reinit. Change-ID: I03eb7afde25727198ef620f8b4e78bb667a11370 Signed-off-by: Mitch Williams <mitch.a.williams@intel.com> Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
2014-06-05i40evf: fix crash when changing ring sizesMitch Williams
i40evf_set_ringparam was broken in several ways. First, it only changed the size of the first ring, and second, changing the ring size would often result in a panic because it would change the count before deallocating resources, causing the driver to either free nonexistent buffers, or leak leftover buffers. Fix this by storing the descriptor count in the adapter structure, and updating the count for each ring each time we allocate them. This ensures that we always free the right size ring, and always end up with the requested count when the device is (re)opened. Change-ID: I298396cd3d452ba8509d9f2d33a93f25868a9a55 Signed-off-by: Mitch Williams <mitch.a.williams@intel.com> Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
2014-06-05sched: Fix sched_policy < 0 comparisonRichard Weinberger
attr.sched_policy is u32, therefore a comparison against < 0 is never true. Fix this by casting sched_policy to int. This issue was reported by coverity CID 1219934. Fixes: dbdb22754fde ("sched: Disallow sched_attr::sched_policy < 0") Signed-off-by: Richard Weinberger <richard@nod.at> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1401741514-7045-1-git-send-email-richard@nod.at Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-06-05sched/numa: Fix use of spin_{un}lock_irq() when interrupts are disabledSteven Rostedt
As Peter Zijlstra told me, we have the following path: do_exit() exit_itimers() itimer_delete() spin_lock_irqsave(&timer->it_lock, &flags); timer_delete_hook(timer); kc->timer_del(timer) := posix_cpu_timer_del() put_task_struct() __put_task_struct() task_numa_free() spin_lock(&grp->lock); Which means that task_numa_free() can be called with interrupts disabled, which means that we should not be using spin_lock_irq() but spin_lock_irqsave() instead. Otherwise we are enabling interrupts while holding an interrupt unsafe lock! Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner<tglx@linutronix.de> Cc: Mike Galbraith <umgwanakikbuti@gmail.com> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20140527182541.GH11096@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-06-05i40evf: set descriptor multiple to 32Mitch Williams
Hardware requires descriptors to be allocated in groups of 32. Change-ID: I752ccc96769d1bd8d3018c004b8aeff464045bf2 Signed-off-by: Mitch Williams <mitch.a.williams@intel.com> Tested-by: Sibai Li <sibai.li@intel.com> Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
2014-06-05backlight: gpio-backlight: Fix warning when the GPIO is on a I2C chipTony Lindgren
If the GPIO for the backlight is on an I2C chip, we currently get nasty warnings like this during the boot: WARNING: CPU: 0 PID: 6 at drivers/gpio/gpiolib.c:2364 gpiod_set_raw_value+0x40/0x4c() Modules linked in: CPU: 0 PID: 6 Comm: kworker/u2:0 Not tainted 3.15.0-rc4-12393-gcde9f4e #400 Workqueue: deferwq deferred_probe_work_func [<c0014cbc>] (unwind_backtrace) from [<c001191c>] (show_stack+0x10/0x14) [<c001191c>] (show_stack) from [<c0566ae0>] (dump_stack+0x80/0x9c) [<c0566ae0>] (dump_stack) from [<c003f61c>] (warn_slowpath_common+0x68/0x8c) [<c003f61c>] (warn_slowpath_common) from [<c003f65c>] (warn_slowpath_null+0x1c/0x24) [<c003f65c>] (warn_slowpath_null) from [<c02f7e10>] (gpiod_set_raw_value+0x40/0x4c) [<c02f7e10>] (gpiod_set_raw_value) from [<c0308fbc>] (gpio_backlight_update_status+0x4c/0x74) [<c0308fbc>] (gpio_backlight_update_status) from [<c030914c>] (gpio_backlight_probe+0x168/0x254) [<c030914c>] (gpio_backlight_probe) from [<c0378fa8>] (platform_drv_probe+0x18/0x48) [<c0378fa8>] (platform_drv_probe) from [<c0377c40>] (driver_probe_device+0x10c/0x238) [<c0377c40>] (driver_probe_device) from [<c0376330>] (bus_for_each_drv+0x44/0x8c) [<c0376330>] (bus_for_each_drv) from [<c0377afc>] (device_attach+0x74/0x8c) [<c0377afc>] (device_attach) from [<c03771c4>] (bus_probe_device+0x88/0xb0) [<c03771c4>] (bus_probe_device) from [<c03775c8>] (deferred_probe_work_func+0x64/0x94) [<c03775c8>] (deferred_probe_work_func) from [<c00572e8>] (process_one_work+0x1b4/0x4bc) [<c00572e8>] (process_one_work) from [<c00579d0>] (worker_thread+0x11c/0x398) [<c00579d0>] (worker_thread) from [<c005dfd8>] (kthread+0xc8/0xe4) [<c005dfd8>] (kthread) from [<c000e768>] (ret_from_fork+0x14/0x2c) Fix this by using gpio_set_value_cansleep() as suggested in drivers/gpio/gpiolib.c:2364. This is what the other backlight drivers are also doing. Signed-off-by: Tony Lindgren <tony@atomide.com> Acked-by: Jingoo Han <jg1.han@samsung.com> Signed-off-by: Lee Jones <lee.jones@linaro.org>
2014-06-05i40e: clamp jumbo frame sizeJesse Brandeburg
The driver was allowing the user to set larger size MTU than the hardware was being configured to support. The driver was already using VLAN_HLEN when setting the hardware max receivable frame size, so just add it to the netdev MTU set entry point as well. Change-ID: Ie20e2a35d04f8c411253e255bea79ca69aaeaea3 Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com> Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
2014-06-05i40e/i40evf: remove unused RX_LRO defineJesse Brandeburg
Remove unused defines and macros for RX_LRO. Change-ID: I8ca6715edfa62b56837417a1c4ff68c2345dab6e Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com> Tested-by: Jim Young <jamesx.m.young@intel.com> Tested-by: Sibai Li <sibai.li@intel.com> Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
2014-06-05Merge tag 'perf-core-for-mingo' of ↵Ingo Molnar
git://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf into perf/core Pull perf/core improvements and fixes from Jiri Olsa: * Warn the user when trace command is not available (Arnaldo Carvalho de Melo) * Add warning when disabling perl scripting support due to missing devel files (Arnaldo Carvalho de Melo) * Consider header files outside perf directory in tags target (Sebastian Andrzej Siewior) * Allow overriding sysfs and proc finding with env var (Cody P Schafer) * Fix "==" into "=" in ui_browser__warning assignment (zhangdianfang) * Factor elide bool handling in sort code (Jiri Olsa) * Fix poll return value propagation (Jiri Olsa) * Fix 'make help' message error (Jianyu Zhan) Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-06-05locking/rwsem: Fix checkpatch.pl warningsAndrew Morton
WARNING: line over 80 characters #205: FILE: kernel/locking/rwsem-xadd.c:275: + old = cmpxchg(&sem->count, count, count + RWSEM_ACTIVE_WRITE_BIAS); WARNING: line over 80 characters #376: FILE: kernel/locking/rwsem-xadd.c:434: + * If there were already threads queued before us and there are no WARNING: line over 80 characters #377: FILE: kernel/locking/rwsem-xadd.c:435: + * active writers, the lock must be read owned; so we try to wake total: 0 errors, 3 warnings, 417 lines checked Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Davidlohr Bueso <davidlohr@hp.com> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/n/tip-pn6pslaplw031lykweojsn8c@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-06-05locking/rwsem: Fix warnings for CONFIG_RWSEM_GENERIC_SPINLOCKDavidlohr Bueso
Optimistic spinning is only used by the xadd variant of rw-semaphores. Make sure that we use the old version of the __RWSEM_INITIALIZER macro for systems that rely on the spinlock one, otherwise warnings can be triggered, such as the following reported on an arm box: ipc/ipcns_notifier.c:22:8: warning: excess elements in struct initializer [enabled by default] ipc/ipcns_notifier.c:22:8: warning: (near initialization for 'ipcns_chain.rwsem') [enabled by default] ipc/ipcns_notifier.c:22:8: warning: excess elements in struct initializer [enabled by default] ipc/ipcns_notifier.c:22:8: warning: (near initialization for 'ipcns_chain.rwsem') [enabled by default] Signed-off-by: Davidlohr Bueso <davidlohr@hp.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul McKenney <paulmck@linux.vnet.ibm.com> Cc: Michel Lespinasse <walken@google.com> Cc: Peter Hurley <peter@hurleysoftware.com> Cc: Alex Shi <alex.shi@linaro.org> Cc: Rik van Riel <riel@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Jason Low <jason.low2@hp.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Chris Mason <clm@fb.com> Cc: Josef Bacik <jbacik@fusionio.com> Link: http://lkml.kernel.org/r/1400545677.6399.10.camel@buesod1.americas.hpqcorp.net Signed-off-by: Ingo Molnar <mingo@kernel.org>