include, scx_lavd: Prioritize a task woken by a hardirq or softirq. #3261
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The updated version has the four helpers: bpf_in_nmi(), bpf_in_hardirq(), bpf_in_serving_softirq(), and bpf_in_task(). Signed-off-by: Changwoo Min <changwoo@igalia.com>
In a similar vein to checking whether a waker is an RT/DL task, we increase the task's latency-criticality when it is woken from an interrupt context: either a hardirq (top half) or a softirq (bottom half). - hardirq: The top half of an interrupt processing (e.g., mouse move, keypress, disk I/O completion, or GPU V-Sync) has just been completed, and it hands off further processing to a fair task. The task that was waiting for this specific hardware signal gets the "Express Lane." - softirq: The kernel just finished the bottom half of an interrupt processing, like network packets and timers. If a packet arrives for your Browser, or a timer expires for a frame refresh, the task gets a "High" boost. This keeps the data pipeline flowing smoothly. Note that the irq-boosted criticality will flow through the forward & backward propagation mechanisms. Signed-off-by: Changwoo Min <changwoo@igalia.com>
daidavid
approved these changes
Jan 28, 2026
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We increase the task's latency-criticality when it is woken from an interrupt context. To use test if a BPF program runs in an interrupt context, we sync
bpf_experimental.hfrom the latest version in bpf-next.