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6712c4fefc
Direct writes to p->scx.dsq_vtime are deprecated in favor of scx_bpf_task_set_dsq_vtime(). Update scx_simple, scx_flatcg, and select_cpu_vtime selftest to use the new kfunc with scale_by_task_weight_inverse(). Signed-off-by: Cheng-Yang Chou <yphbchou0911@gmail.com> Reviewed-by: Andrea Righi <arighi@nvidia.com> Signed-off-by: Tejun Heo <tj@kernel.org>
95 lines
2.4 KiB
C
95 lines
2.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* A scheduler that validates that enqueue flags are properly stored and
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* applied at dispatch time when a task is directly dispatched from
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* ops.select_cpu(). We validate this by using scx_bpf_dsq_insert_vtime(),
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* and making the test a very basic vtime scheduler.
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*
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* Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
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* Copyright (c) 2024 David Vernet <dvernet@meta.com>
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* Copyright (c) 2024 Tejun Heo <tj@kernel.org>
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*/
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#include <scx/common.bpf.h>
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char _license[] SEC("license") = "GPL";
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volatile bool consumed;
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static u64 vtime_now;
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#define VTIME_DSQ 0
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static inline bool vtime_before(u64 a, u64 b)
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{
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return (s64)(a - b) < 0;
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}
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static inline u64 task_vtime(const struct task_struct *p)
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{
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u64 vtime = p->scx.dsq_vtime;
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if (vtime_before(vtime, vtime_now - SCX_SLICE_DFL))
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return vtime_now - SCX_SLICE_DFL;
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else
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return vtime;
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}
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s32 BPF_STRUCT_OPS(select_cpu_vtime_select_cpu, struct task_struct *p,
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s32 prev_cpu, u64 wake_flags)
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{
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s32 cpu;
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cpu = scx_bpf_pick_idle_cpu(p->cpus_ptr, 0);
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if (cpu >= 0)
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goto ddsp;
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cpu = prev_cpu;
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scx_bpf_test_and_clear_cpu_idle(cpu);
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ddsp:
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scx_bpf_dsq_insert_vtime(p, VTIME_DSQ, SCX_SLICE_DFL, task_vtime(p), 0);
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return cpu;
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}
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void BPF_STRUCT_OPS(select_cpu_vtime_dispatch, s32 cpu, struct task_struct *p)
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{
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if (scx_bpf_dsq_move_to_local(VTIME_DSQ, 0))
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consumed = true;
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}
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void BPF_STRUCT_OPS(select_cpu_vtime_running, struct task_struct *p)
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{
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if (vtime_before(vtime_now, p->scx.dsq_vtime))
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vtime_now = p->scx.dsq_vtime;
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}
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void BPF_STRUCT_OPS(select_cpu_vtime_stopping, struct task_struct *p,
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bool runnable)
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{
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u64 delta = scale_by_task_weight_inverse(p, SCX_SLICE_DFL - p->scx.slice);
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scx_bpf_task_set_dsq_vtime(p, p->scx.dsq_vtime + delta);
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}
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void BPF_STRUCT_OPS(select_cpu_vtime_enable, struct task_struct *p)
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{
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scx_bpf_task_set_dsq_vtime(p, vtime_now);
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}
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s32 BPF_STRUCT_OPS_SLEEPABLE(select_cpu_vtime_init)
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{
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return scx_bpf_create_dsq(VTIME_DSQ, -1);
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}
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SEC(".struct_ops.link")
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struct sched_ext_ops select_cpu_vtime_ops = {
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.select_cpu = (void *) select_cpu_vtime_select_cpu,
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.dispatch = (void *) select_cpu_vtime_dispatch,
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.running = (void *) select_cpu_vtime_running,
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.stopping = (void *) select_cpu_vtime_stopping,
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.enable = (void *) select_cpu_vtime_enable,
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.init = (void *) select_cpu_vtime_init,
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.name = "select_cpu_vtime",
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.timeout_ms = 1000U,
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};
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