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2009-10-09Revert "x86, timers: Check for pending timers after (device) interrupts"Ingo Molnar
This reverts commit 9bcbdd9c58617f1301dd4f17c738bb9bc73aca70. The real bug producing LatencyTop latencies has been fixed in: f5dc375: sched: Update the clock of runqueue select_task_rq() selected And the commit being reverted here triggers local timer processing from every device IRQ. If device IRQs come in at a high frequency, this could cause a performance regression. The commit being reverted here purely 'fixed' the reported latency as a side effect, because CPUs were being moved out of idle more often. Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Frans Pop <elendil@planet.nl> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Thomas Gleixner <tglx@linutronix.de> LKML-Reference: <20091008064041.67219b13@infradead.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-10-08x86, timers: Check for pending timers after (device) interruptsArjan van de Ven
Now that range timers and deferred timers are common, I found a problem with these using the "perf timechart" tool. Frans Pop also reported high scheduler latencies via LatencyTop, when using iwlagn. It turns out that on x86, these two 'opportunistic' timers only get checked when another "real" timer happens. These opportunistic timers have the objective to save power by hitchhiking on other wakeups, as to avoid CPU wakeups by themselves as much as possible. The change in this patch runs this check not only at timer interrupts, but at all (device) interrupts. The effect is that: 1) the deferred timers/range timers get delayed less 2) the range timers cause less wakeups by themselves because the percentage of hitchhiking on existing wakeup events goes up. I've verified the working of the patch using "perf timechart", the original exposed bug is gone with this patch. Frans also reported success - the latencies are now down in the expected ~10 msec range. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Tested-by: Frans Pop <elendil@planet.nl> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Mike Galbraith <efault@gmx.de> LKML-Reference: <20091008064041.67219b13@infradead.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-06-11Merge branch 'linus' into x86/mce3Ingo Molnar
Conflicts: arch/x86/kernel/cpu/mcheck/mce_64.c arch/x86/kernel/irq.c Merge reason: Resolve the conflicts above. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-06-11Merge branch 'kvm-updates/2.6.31' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds
* 'kvm-updates/2.6.31' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (138 commits) KVM: Prevent overflow in largepages calculation KVM: Disable large pages on misaligned memory slots KVM: Add VT-x machine check support KVM: VMX: Rename rmode.active to rmode.vm86_active KVM: Move "exit due to NMI" handling into vmx_complete_interrupts() KVM: Disable CR8 intercept if tpr patching is active KVM: Do not migrate pending software interrupts. KVM: inject NMI after IRET from a previous NMI, not before. KVM: Always request IRQ/NMI window if an interrupt is pending KVM: Do not re-execute INTn instruction. KVM: skip_emulated_instruction() decode instruction if size is not known KVM: Remove irq_pending bitmap KVM: Do not allow interrupt injection from userspace if there is a pending event. KVM: Unprotect a page if #PF happens during NMI injection. KVM: s390: Verify memory in kvm run KVM: s390: Sanity check on validity intercept KVM: s390: Unlink vcpu on destroy - v2 KVM: s390: optimize float int lock: spin_lock_bh --> spin_lock KVM: s390: use hrtimer for clock wakeup from idle - v2 KVM: s390: Fix memory slot versus run - v3 ...
2009-06-10KVM: use smp_send_reschedule in kvm_vcpu_kickMarcelo Tosatti
KVM uses a function call IPI to cause the exit of a guest running on a physical cpu. For virtual interrupt notification there is no need to wait on IPI receival, or to execute any function. This is exactly what the reschedule IPI does, without the overhead of function IPI. So use it instead of smp_call_function_single in kvm_vcpu_kick. Also change the "guest_mode" variable to a bit in vcpu->requests, and use that to collapse multiple IPI's that would be issued between the first one and zeroing of guest mode. This allows kvm_vcpu_kick to called with interrupts disabled. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-06-03x86: fix panic with interrupts off (needed for MCE)Andi Kleen
For some time each panic() called with interrupts disabled triggered the !irqs_disabled() WARN_ON in smp_call_function(), producing ugly backtraces and confusing users. This is a common situation with machine checks for example which tend to call panic with interrupts disabled, but will also hit in other situations e.g. panic during early boot. In fact it means that panic cannot be called in many circumstances, which would be bad. This all started with the new fancy queued smp_call_function, which is then used by the shutdown path to shut down the other CPUs. On closer examination it turned out that the fancy RCU smp_call_function() does lots of things not suitable in a panic situation anyways, like allocating memory and relying on complex system state. I originally tried to patch this over by checking for panic there, but it was quite complicated and the original patch was also not very popular. This also didn't fix some of the underlying complexity problems. The new code in post 2.6.29 tries to patch around this by checking for oops_in_progress, but that is not enough to make this fully safe and I don't think that's a real solution because panic has to be reliable. So instead use an own vector to reboot. This makes the reboot code extremly straight forward, which is definitely a big plus in a panic situation where it is important to avoid relying on too much kernel state. The new simple code is also safe to be called from interupts off region because it is very very simple. There can be situations where it is important that panic is reliable. For example on a fatal machine check the panic is needed to get the system up again and running as quickly as possible. So it's important that panic is reliable and all function it calls simple. This is why I came up with this simple vector scheme. It's very hard to beat in simplicity. Vectors are not particularly precious anymore since all big systems are using per CPU vectors. Another possibility would have been to use an NMI similar to kdump, but there is still the problem that NMIs don't work reliably on some systems due to BIOS issues. NMIs would have been able to stop CPUs running with interrupts off too. In the sake of universal reliability I opted for using a non NMI vector for now. I put the reboot vector into the highest priority bucket of the APIC vectors and moved the 64bit UV_BAU message down instead into the next lower priority. [ Impact: bug fix, fixes an old regression ] Signed-off-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-04-12x86: smp.c - align smp_ops assignmentsCyrill Gorcunov
Impact: cleanup It's a bit hard to parse by eyes without them being aligned. Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> LKML-Reference: <20090412165058.924175574@openvz.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-17x86, apic: remove genapic.hIngo Molnar
Impact: cleanup Remove genapic.h and remove all references to it. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-31x86: update copyrightsIngo Molnar
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-29x86, smp: remove mach_ipi.hIngo Molnar
Move mach_ipi.h definitions into genapic.h. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-29x86: remove mach_apic.hIngo Molnar
Spread mach_apic.h definitions into genapic.h. (with some knock-on effects on smp.h and apic.h.) Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-28x86, apic: untangle the send_IPI_*() jungleIngo Molnar
Our send_IPI_*() methods and definitions are a twisted mess: the same symbol is defined to different things depending on .config details, in a non-transparent way. - spread out the quirks into separately named per apic driver methods - prefix the standard PC methods with default_ - get rid of wrapper macro obfuscation - clean up various details Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-10Merge branch 'x86-fixes-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (36 commits) x86: fix section mismatch warnings in mcheck/mce_amd_64.c x86: offer frame pointers in all build modes x86: remove duplicated #include's x86: k8 numa register active regions later x86: update Alan Cox's email addresses x86: rename all fields of mpc_table mpc_X to X x86: rename all fields of mpc_oemtable oem_X to X x86: rename all fields of mpc_bus mpc_X to X x86: rename all fields of mpc_cpu mpc_X to X x86: rename all fields of mpc_intsrc mpc_X to X x86: rename all fields of mpc_lintsrc mpc_X to X x86: rename all fields of mpc_iopic mpc_X to X x86: irqinit_64.c init_ISA_irqs should be static Documentation/x86/boot.txt: payload length was changed to payload_length x86: setup_percpu.c fix style problems x86: irqinit_64.c fix style problems x86: irqinit_32.c fix style problems x86: i8259.c fix style problems x86: irq_32.c fix style problems x86: ioport.c fix style problems ...
2009-01-05x86: update Alan Cox's email addressesAlan Cox
Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-04x86: cleanup remaining cpumask_t ops in smpboot codeMike Travis
Impact: use new cpumask API to reduce memory and stack usage Allocate the following local cpumasks based on the number of cpus that are present. References will use new cpumask API. (Currently only modified for x86_64, x86_32 continues to use the *_map variants.) cpu_callin_mask cpu_callout_mask cpu_initialized_mask cpu_sibling_setup_mask Provide the following accessor functions: struct cpumask *cpu_sibling_mask(int cpu) struct cpumask *cpu_core_mask(int cpu) Other changes are when setting or clearing the cpu online, possible or present maps, use the accessor functions. Signed-off-by: Mike Travis <travis@sgi.com> Acked-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-02Merge branch 'cpus4096-for-linus-2' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'cpus4096-for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (66 commits) x86: export vector_used_by_percpu_irq x86: use logical apicid in x2apic_cluster's x2apic_cpu_mask_to_apicid_and() sched: nominate preferred wakeup cpu, fix x86: fix lguest used_vectors breakage, -v2 x86: fix warning in arch/x86/kernel/io_apic.c sched: fix warning in kernel/sched.c sched: move test_sd_parent() to an SMP section of sched.h sched: add SD_BALANCE_NEWIDLE at MC and CPU level for sched_mc>0 sched: activate active load balancing in new idle cpus sched: bias task wakeups to preferred semi-idle packages sched: nominate preferred wakeup cpu sched: favour lower logical cpu number for sched_mc balance sched: framework for sched_mc/smt_power_savings=N sched: convert BALANCE_FOR_xx_POWER to inline functions x86: use possible_cpus=NUM to extend the possible cpus allowed x86: fix cpu_mask_to_apicid_and to include cpu_online_mask x86: update io_apic.c to the new cpumask code x86: Introduce topology_core_cpumask()/topology_thread_cpumask() x86: xen: use smp_call_function_many() x86: use work_on_cpu in x86/kernel/cpu/mcheck/mce_amd_64.c ... Fixed up trivial conflict in kernel/time/tick-sched.c manually
2008-12-23Merge branch 'x86/irq' into x86/coreIngo Molnar
2008-12-16x86: cosmetic changes apic-related files.Mike Travis
This patch simply changes cpumask_t to struct cpumask and similar trivial modernizations. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Mike Travis <travis@sgi.com>
2008-12-16x86 smp: modify send_IPI_mask interface to accept cpumask_t pointersMike Travis
Impact: cleanup, change parameter passing * Change genapic interfaces to accept cpumask_t pointers where possible. * Modify external callers to use cpumask_t pointers in function calls. * Create new send_IPI_mask_allbutself which is the same as the send_IPI_mask functions but removes smp_processor_id() from list. This removes another common need for a temporary cpumask_t variable. * Functions that used a temp cpumask_t variable for: cpumask_t allbutme = cpu_online_map; cpu_clear(smp_processor_id(), allbutme); if (!cpus_empty(allbutme)) ... become: if (!cpus_equal(cpu_online_map, cpumask_of_cpu(cpu))) ... * Other minor code optimizations (like using cpus_clear instead of CPU_MASK_NONE, etc.) Applies to linux-2.6.tip/master. Signed-off-by: Mike Travis <travis@sgi.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Acked-by: Ingo Molnar <mingo@elte.hu>
2008-12-12x86: hardirq: introduce inc_irq_stat()Hiroshi Shimamoto
Impact: cleanup Introduce inc_irq_stat() macro and unify irq_stat accounting code. Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-11x86: call machine_shutdown and stop all CPUs in native_machine_haltIvan Vecera
Impact: really halt all CPUs on halt Function machine_halt (resp. native_machine_halt) is empty for x86 architectures. When command 'halt -f' is invoked, the message "System halted." is displayed but this is not really true because all CPUs are still running. There are also similar inconsistencies for other arches (some uses power-off for halt or forever-loop with IRQs enabled/disabled). IMO there should be used the same approach for all architectures OR what does the message "System halted" really mean? This patch fixes it for x86. Signed-off-by: Ivan Vecera <ivecera@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-25x86: add cpu hotplug hooks into smp_opsAlex Nixon
Signed-off-by: Alex Nixon <alex.nixon@citrix.com> Acked-by: Jeremy Fitzhardinge <jeremy@goop.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-06generic-ipi: fixletJens Axboe
create proper stackframe. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-26smp_call_function: get rid of the unused nonatomic/retry argumentJens Axboe
It's never used and the comments refer to nonatomic and retry interchangably. So get rid of it. Acked-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-06-26x86: convert to generic helpers for IPI function callsJens Axboe
This converts x86, x86-64, and xen to use the new helpers for smp_call_function() and friends, and adds support for smp_call_function_single(). Acked-by: Ingo Molnar <mingo@elte.hu> Acked-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-05-13x86: fix app crashes after SMP resumeHugh Dickins
After resume on a 2cpu laptop, kernel builds collapse with a sed hang, sh or make segfault (often on 20295564), real-time signal to cc1 etc. Several hurdles to jump, but a manually-assisted bisect led to -rc1's d2bcbad5f3ad38a1c09861bca7e252dde7bb8259 x86: do not zap_low_mappings in __smp_prepare_cpus. Though the low mappings were removed at bootup, they were left behind (with Global flags helping to keep them in TLB) after resume or cpu online, causing the crashes seen. Reinstate zap_low_mappings (with local __flush_tlb_all) for each cpu_up on x86_32. This used to be serialized by smp_commenced_mask: that's now gone, but a low_mappings flag will do. No need for native_smp_cpus_done to repeat the zap: let mem_init zap BSP's low mappings just like on UP. (In passing, fix error code from native_cpu_up: do_boot_cpu returns a variety of diagnostic values, Dprintk what it says but convert to -EIO. And save_pg_dir separately before zap_low_mappings: doesn't matter now, but zapping twice in succession wiped out resume's swsusp_pg_dir.) That worked well on the duo and one quad, but wouldn't boot 3rd or 4th cpu on P4 Xeon, oopsing just after unlock_ipi_call_lock. The TLB flush IPI now being sent reveals a long-standing bug: the booting cpu has its APIC readied in smp_callin at the top of start_secondary, but isn't put into the cpu_online_map until just before that unlock_ipi_call_lock. So native_smp_call_function_mask to online cpus would send_IPI_allbutself, including the cpu just coming up, though it has been excluded from the count to wait for: by the time it handles the IPI, the call data on native_smp_call_function_mask's stack may well have been overwritten. So fall back to send_IPI_mask while cpu_online_map does not match cpu_callout_map: perhaps there's a better APICological fix to be made at the start_secondary end, but I wouldn't know that. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-17x86: move ipi definitions to mach_ipi.hGlauber Costa
take them out of the x86_64-only asm/mach_apic.h Signed-off-by: Glauber Costa <gcosta@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-17x86: Don't send RESCHEDULE_VECTOR to offlined cpusGautham R Shenoy
In the x86 native_smp_send_reschedule_function(), don't send the IPI if the cpu has gone offline already. Warn nevertheless!! Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-17x86: get rid of smp_32.c and smp_64.cGlauber Costa
This patch merges the copyright notices, and valuable comments that were left back on smp_{32,64}.c. With that, files are empty, and are deleted Signed-off-by: Glauber Costa <gcosta@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-17x86: create smp.cGlauber Costa
this patch moves all the functions and data structures that look like exactly the same from smp_{32,64}.c to smp.c Signed-off-by: Glauber Costa <gcosta@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>