0ad83caa21
If you try to enable NOHZ_FULL on a guest today, you'll get the following error when the guest tries to deactivate the scheduler tick: WARNING: CPU: 3 PID: 2182 at kernel/time/tick-sched.c:192 can_stop_full_tick+0xb9/0x290() NO_HZ FULL will not work with unstable sched clock CPU: 3 PID: 2182 Comm: kworker/3:1 Not tainted 4.0.0-10545-gb9bb6fb #204 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 Workqueue: events flush_to_ldisc ffffffff8162a0c7 ffff88011f583e88 ffffffff814e6ba0 0000000000000002 ffff88011f583ed8 ffff88011f583ec8 ffffffff8104d095 ffff88011f583eb8 0000000000000000 0000000000000003 0000000000000001 0000000000000001 Call Trace: <IRQ> [<ffffffff814e6ba0>] dump_stack+0x4f/0x7b [<ffffffff8104d095>] warn_slowpath_common+0x85/0xc0 [<ffffffff8104d146>] warn_slowpath_fmt+0x46/0x50 [<ffffffff810bd2a9>] can_stop_full_tick+0xb9/0x290 [<ffffffff810bd9ed>] tick_nohz_irq_exit+0x8d/0xb0 [<ffffffff810511c5>] irq_exit+0xc5/0x130 [<ffffffff814f180a>] smp_apic_timer_interrupt+0x4a/0x60 [<ffffffff814eff5e>] apic_timer_interrupt+0x6e/0x80 <EOI> [<ffffffff814ee5d1>] ? _raw_spin_unlock_irqrestore+0x31/0x60 [<ffffffff8108bbc8>] __wake_up+0x48/0x60 [<ffffffff8134836c>] n_tty_receive_buf_common+0x49c/0xba0 [<ffffffff8134a6bf>] ? tty_ldisc_ref+0x1f/0x70 [<ffffffff81348a84>] n_tty_receive_buf2+0x14/0x20 [<ffffffff8134b390>] flush_to_ldisc+0xe0/0x120 [<ffffffff81064d05>] process_one_work+0x1d5/0x540 [<ffffffff81064c81>] ? process_one_work+0x151/0x540 [<ffffffff81065191>] worker_thread+0x121/0x470 [<ffffffff81065070>] ? process_one_work+0x540/0x540 [<ffffffff8106b4df>] kthread+0xef/0x110 [<ffffffff8106b3f0>] ? __kthread_parkme+0xa0/0xa0 [<ffffffff814ef4f2>] ret_from_fork+0x42/0x70 [<ffffffff8106b3f0>] ? __kthread_parkme+0xa0/0xa0 ---[ end trace 06e3507544a38866 ]--- However, it turns out that kvmclock does provide a stable sched_clock callback. So, let the scheduler know this which in turn makes NOHZ_FULL work in the guest. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> |
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| .. | ||
| acpi | ||
| apic | ||
| cpu | ||
| kprobes | ||
| .gitignore | ||
| alternative.c | ||
| amd_gart_64.c | ||
| amd_nb.c | ||
| apb_timer.c | ||
| aperture_64.c | ||
| apm_32.c | ||
| asm-offsets_32.c | ||
| asm-offsets_64.c | ||
| asm-offsets.c | ||
| audit_64.c | ||
| bootflag.c | ||
| check.c | ||
| cpuid.c | ||
| crash_dump_32.c | ||
| crash_dump_64.c | ||
| crash.c | ||
| devicetree.c | ||
| doublefault.c | ||
| dumpstack_32.c | ||
| dumpstack_64.c | ||
| dumpstack.c | ||
| e820.c | ||
| early_printk.c | ||
| early-quirks.c | ||
| entry_32.S | ||
| entry_64.S | ||
| espfix_64.c | ||
| ftrace.c | ||
| head32.c | ||
| head64.c | ||
| head_32.S | ||
| head_64.S | ||
| head.c | ||
| hpet.c | ||
| hw_breakpoint.c | ||
| i386_ksyms_32.c | ||
| i387.c | ||
| i8237.c | ||
| i8253.c | ||
| i8259.c | ||
| io_delay.c | ||
| ioport.c | ||
| iosf_mbi.c | ||
| irq_32.c | ||
| irq_64.c | ||
| irq_work.c | ||
| irq.c | ||
| irqinit.c | ||
| jump_label.c | ||
| kdebugfs.c | ||
| kexec-bzimage64.c | ||
| kgdb.c | ||
| ksysfs.c | ||
| kvm.c | ||
| kvmclock.c | ||
| ldt.c | ||
| livepatch.c | ||
| machine_kexec_32.c | ||
| machine_kexec_64.c | ||
| Makefile | ||
| mcount_64.S | ||
| mmconf-fam10h_64.c | ||
| module.c | ||
| mpparse.c | ||
| msr.c | ||
| nmi_selftest.c | ||
| nmi.c | ||
| paravirt_patch_32.c | ||
| paravirt_patch_64.c | ||
| paravirt-spinlocks.c | ||
| paravirt.c | ||
| pci-calgary_64.c | ||
| pci-dma.c | ||
| pci-iommu_table.c | ||
| pci-nommu.c | ||
| pci-swiotlb.c | ||
| pcspeaker.c | ||
| perf_regs.c | ||
| pmc_atom.c | ||
| pmem.c | ||
| probe_roms.c | ||
| process_32.c | ||
| process_64.c | ||
| process.c | ||
| ptrace.c | ||
| pvclock.c | ||
| quirks.c | ||
| reboot_fixups_32.c | ||
| reboot.c | ||
| relocate_kernel_32.S | ||
| relocate_kernel_64.S | ||
| resource.c | ||
| rtc.c | ||
| setup_percpu.c | ||
| setup.c | ||
| signal.c | ||
| smp.c | ||
| smpboot.c | ||
| stacktrace.c | ||
| step.c | ||
| sys_x86_64.c | ||
| syscall_32.c | ||
| syscall_64.c | ||
| sysfb_efi.c | ||
| sysfb_simplefb.c | ||
| sysfb.c | ||
| tboot.c | ||
| tce_64.c | ||
| test_nx.c | ||
| test_rodata.c | ||
| time.c | ||
| tls.c | ||
| tls.h | ||
| topology.c | ||
| trace_clock.c | ||
| tracepoint.c | ||
| traps.c | ||
| tsc_msr.c | ||
| tsc_sync.c | ||
| tsc.c | ||
| uprobes.c | ||
| verify_cpu.S | ||
| vm86_32.c | ||
| vmlinux.lds.S | ||
| vsmp_64.c | ||
| vsyscall_64.c | ||
| vsyscall_emu_64.S | ||
| vsyscall_gtod.c | ||
| vsyscall_trace.h | ||
| x86_init.c | ||
| x8664_ksyms_64.c | ||
| xsave.c | ||