a1ede341b3
On devices with a CPU that contains heterogeneous cores (e.g., big.LITTLE), it can be beneficial to place some performance-critical IRQs and kthreads onto the performance CPU cluster in order to improve performance. This commit adds the following APIs: -kthread_run_perf_critical() to create and start a perf-critical kthread -irq_set_perf_affinity() to mark an active IRQ as perf-critical -IRQF_PERF_CRITICAL to schedule an IRQ and any threads it may have onto performance CPUs -PF_PERF_CRITICAL to mark a process (mainly a kthread) as performance critical (this is used by kthread_run_perf_critical()) In order to accommodate this new API, the following changes are made: -Performance-critical IRQs are distributed evenly among online CPUs available in cpu_perf_mask -Performance-critical IRQs have their affinities reaffined upon exit from suspend (since the affinities are broken when non-boot CPUs are disabled) -Performance-critical IRQs and their threads have their affinities reset upon entering suspend, so that upon immediate suspend exit (when only the boot CPU is online), interrupts can be processed and interrupt threads can be scheduled onto an online CPU (otherwise we'd hit a kernel BUG) -__set_cpus_allowed_ptr() is modified to enforce a performance-critical kthread's affinity -Perf-critical IRQs are marked with IRQD_AFFINITY_MANAGED so userspace can't mess with their affinity Signed-off-by: Sultan Alsawaf <sultan@kerneltoast.com> |
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| acpi | ||
| asm-generic | ||
| clocksource | ||
| crypto | ||
| drm | ||
| dt-bindings | ||
| keys | ||
| kvm | ||
| linux | ||
| math-emu | ||
| media | ||
| memory | ||
| misc | ||
| net | ||
| pcmcia | ||
| ras | ||
| rdma | ||
| rxrpc | ||
| scsc | ||
| scsi | ||
| sdp | ||
| soc | ||
| sound | ||
| target | ||
| trace | ||
| uapi | ||
| video | ||
| xen | ||
| Kbuild | ||