mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-10-03 23:58:05 +00:00
c06aed0e31
The jiffies_till_sched_qs value used to determine how old a grace period must be before RCU enlists the help of the scheduler to force a quiescent state on the holdout CPU. Currently, this defaults to HZ/10 regardless of system size and may be set only at boot time. This can be a problem for very large systems, because if the values of the jiffies_till_first_fqs and jiffies_till_next_fqs kernel parameters are left at their defaults, they are calculated to increase as the number of CPUs actually configured on the system increases. Thus, on a sufficiently large system, RCU would enlist the help of the scheduler before the grace-period kthread had a chance to scan for idle CPUs, which wastes CPU time. This commit therefore allows jiffies_till_sched_qs to be set, if desired, but if left as default, computes is as jiffies_till_first_fqs plus twice jiffies_till_next_fqs, thus allowing three force-quiescent-state scans for idle CPUs. This scales with the number of CPUs, providing sensible default values. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> |
||
|---|---|---|
| .. | ||
| ABI | ||
| accelerators | ||
| accounting | ||
| acpi | ||
| admin-guide | ||
| aoe | ||
| arm | ||
| arm64 | ||
| auxdisplay | ||
| backlight | ||
| block | ||
| blockdev | ||
| bpf | ||
| bus-devices | ||
| cdrom | ||
| cgroup-v1 | ||
| cma | ||
| connector | ||
| console | ||
| core-api | ||
| cpu-freq | ||
| cpuidle | ||
| crypto | ||
| dev-tools | ||
| device-mapper | ||
| devicetree | ||
| doc-guide | ||
| driver-api | ||
| driver-model | ||
| early-userspace | ||
| EDID | ||
| extcon | ||
| fault-injection | ||
| fb | ||
| features | ||
| filesystems | ||
| firmware_class | ||
| fmc | ||
| fpga | ||
| gpio | ||
| gpu | ||
| hid | ||
| hwmon | ||
| i2c | ||
| ia64 | ||
| ide | ||
| iio | ||
| infiniband | ||
| input | ||
| ioctl | ||
| isdn | ||
| kbuild | ||
| kdump | ||
| kernel-hacking | ||
| laptops | ||
| leds | ||
| lightnvm | ||
| livepatch | ||
| locking | ||
| m68k | ||
| maintainer | ||
| md | ||
| media | ||
| memory-devices | ||
| mic | ||
| mips | ||
| misc-devices | ||
| mmc | ||
| mtd | ||
| namespaces | ||
| netlabel | ||
| networking | ||
| nfc | ||
| nios2 | ||
| nvdimm | ||
| nvmem | ||
| openrisc | ||
| parisc | ||
| PCI | ||
| pcmcia | ||
| perf | ||
| phy | ||
| platform | ||
| power | ||
| powerpc | ||
| pps | ||
| process | ||
| pti | ||
| ptp | ||
| rapidio | ||
| RCU | ||
| riscv | ||
| s390 | ||
| scheduler | ||
| scsi | ||
| security | ||
| serial | ||
| sh | ||
| sound | ||
| sparc | ||
| sphinx | ||
| sphinx-static | ||
| spi | ||
| sysctl | ||
| target | ||
| thermal | ||
| timers | ||
| trace | ||
| translations | ||
| usb | ||
| userspace-api | ||
| virtual | ||
| vm | ||
| w1 | ||
| watchdog | ||
| wimax | ||
| x86 | ||
| xtensa | ||
| .gitignore | ||
| 00-INDEX | ||
| atomic_bitops.txt | ||
| atomic_t.txt | ||
| bt8xxgpio.txt | ||
| btmrvl.txt | ||
| bus-virt-phys-mapping.txt | ||
| Changes | ||
| clearing-warn-once.txt | ||
| CodingStyle | ||
| conf.py | ||
| cpu-load.txt | ||
| cputopology.txt | ||
| crc32.txt | ||
| dcdbas.txt | ||
| debugging-modules.txt | ||
| debugging-via-ohci1394.txt | ||
| dell_rbu.txt | ||
| digsig.txt | ||
| DMA-API-HOWTO.txt | ||
| DMA-API.txt | ||
| DMA-attributes.txt | ||
| DMA-ISA-LPC.txt | ||
| docutils.conf | ||
| dontdiff | ||
| efi-stub.txt | ||
| eisa.txt | ||
| flexible-arrays.txt | ||
| futex-requeue-pi.txt | ||
| gcc-plugins.txt | ||
| highuid.txt | ||
| hw_random.txt | ||
| hwspinlock.txt | ||
| index.rst | ||
| Intel-IOMMU.txt | ||
| intel_txt.txt | ||
| io-mapping.txt | ||
| io_ordering.txt | ||
| iostats.txt | ||
| IPMI.txt | ||
| IRQ-affinity.txt | ||
| IRQ-domain.txt | ||
| IRQ.txt | ||
| irqflags-tracing.txt | ||
| isa.txt | ||
| isapnp.txt | ||
| kernel-per-CPU-kthreads.txt | ||
| kobject.txt | ||
| kprobes.txt | ||
| kref.txt | ||
| ldm.txt | ||
| lockup-watchdogs.txt | ||
| logo.gif | ||
| logo.txt | ||
| lsm.txt | ||
| lzo.txt | ||
| mailbox.txt | ||
| Makefile | ||
| memory-barriers.txt | ||
| memory-hotplug.txt | ||
| men-chameleon-bus.txt | ||
| nommu-mmap.txt | ||
| ntb.txt | ||
| numastat.txt | ||
| padata.txt | ||
| parport-lowlevel.txt | ||
| percpu-rw-semaphore.txt | ||
| phy.txt | ||
| pi-futex.txt | ||
| pnp.txt | ||
| preempt-locking.txt | ||
| pwm.txt | ||
| rbtree.txt | ||
| remoteproc.txt | ||
| rfkill.txt | ||
| robust-futex-ABI.txt | ||
| robust-futexes.txt | ||
| rpmsg.txt | ||
| rtc.txt | ||
| SAK.txt | ||
| sgi-ioc4.txt | ||
| siphash.txt | ||
| SM501.txt | ||
| smsc_ece1099.txt | ||
| speculation.txt | ||
| static-keys.txt | ||
| SubmittingPatches | ||
| svga.txt | ||
| switchtec.txt | ||
| sync_file.txt | ||
| tee.txt | ||
| this_cpu_ops.txt | ||
| unaligned-memory-access.txt | ||
| vfio-mediated-device.txt | ||
| vfio.txt | ||
| video-output.txt | ||
| xillybus.txt | ||
| xz.txt | ||
| zorro.txt | ||
