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Merge pull request torvalds#115 from sched-ext/enq_flags
Stash enq_flags when marking for direct dispatch
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,94 @@ | ||
| /* SPDX-License-Identifier: GPL-2.0 */ | ||
| /* | ||
| * A scheduler that validates that enqueue flags are properly stored and | ||
| * applied at dispatch time when a task is directly dispatched from | ||
| * ops.select_cpu(). We validate this by using scx_bpf_dispatch_vtime(), and | ||
| * making the test a very basic vtime scheduler. | ||
| * | ||
| * Copyright (c) 2024 Meta Platforms, Inc. and affiliates. | ||
| * Copyright (c) 2024 David Vernet <[email protected]> | ||
| * Copyright (c) 2024 Tejun Heo <[email protected]> | ||
| */ | ||
|
|
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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) | ||
| { | ||
| return (s64)(a - b) < 0; | ||
| } | ||
|
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| static inline u64 task_vtime(const struct task_struct *p) | ||
| { | ||
| u64 vtime = p->scx.dsq_vtime; | ||
|
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| if (vtime_before(vtime, vtime_now - SCX_SLICE_DFL)) | ||
| return vtime_now - SCX_SLICE_DFL; | ||
| else | ||
| return vtime; | ||
| } | ||
|
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||
| s32 BPF_STRUCT_OPS(select_cpu_vtime_select_cpu, struct task_struct *p, | ||
| s32 prev_cpu, u64 wake_flags) | ||
| { | ||
| s32 cpu; | ||
|
|
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| cpu = scx_bpf_pick_idle_cpu(p->cpus_ptr, 0); | ||
| if (cpu >= 0) | ||
| goto ddsp; | ||
|
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| cpu = prev_cpu; | ||
| scx_bpf_test_and_clear_cpu_idle(cpu); | ||
| ddsp: | ||
| scx_bpf_dispatch_vtime(p, VTIME_DSQ, SCX_SLICE_DFL, task_vtime(p), 0); | ||
| return cpu; | ||
| } | ||
|
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| void BPF_STRUCT_OPS(select_cpu_vtime_dispatch, s32 cpu, struct task_struct *p) | ||
| { | ||
| if (scx_bpf_consume(VTIME_DSQ)) | ||
| consumed = true; | ||
| } | ||
|
|
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| void BPF_STRUCT_OPS(select_cpu_vtime_running, struct task_struct *p) | ||
| { | ||
| if (vtime_before(vtime_now, p->scx.dsq_vtime)) | ||
| vtime_now = p->scx.dsq_vtime; | ||
| } | ||
|
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| void BPF_STRUCT_OPS(select_cpu_vtime_stopping, struct task_struct *p, | ||
| bool runnable) | ||
| { | ||
| p->scx.dsq_vtime += (SCX_SLICE_DFL - p->scx.slice) * 100 / p->scx.weight; | ||
| } | ||
|
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| void BPF_STRUCT_OPS(select_cpu_vtime_enable, struct task_struct *p) | ||
| { | ||
| p->scx.dsq_vtime = vtime_now; | ||
| } | ||
|
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| s32 BPF_STRUCT_OPS_SLEEPABLE(select_cpu_vtime_init) | ||
| { | ||
| scx_bpf_switch_all(); | ||
|
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| return scx_bpf_create_dsq(VTIME_DSQ, -1); | ||
| } | ||
|
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| SEC(".struct_ops.link") | ||
| struct sched_ext_ops select_cpu_vtime_ops = { | ||
| .select_cpu = select_cpu_vtime_select_cpu, | ||
| .dispatch = select_cpu_vtime_dispatch, | ||
| .running = select_cpu_vtime_running, | ||
| .stopping = select_cpu_vtime_stopping, | ||
| .enable = select_cpu_vtime_enable, | ||
| .init = select_cpu_vtime_init, | ||
| .name = "select_cpu_vtime", | ||
| .timeout_ms = 1000U, | ||
| }; |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,39 @@ | ||
| /* SPDX-License-Identifier: GPL-2.0 */ | ||
| /* | ||
| * Copyright (c) 2024 Meta Platforms, Inc. and affiliates. | ||
| * Copyright (c) 2024 David Vernet <[email protected]> | ||
| * Copyright (c) 2024 Tejun Heo <[email protected]> | ||
| */ | ||
| #include <stdio.h> | ||
| #include <unistd.h> | ||
| #include <libgen.h> | ||
| #include <bpf/bpf.h> | ||
| #include <scx/common.h> | ||
| #include <sys/wait.h> | ||
| #include "select_cpu_vtime.bpf.skel.h" | ||
| #include "scx_test.h" | ||
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| int main(int argc, char **argv) | ||
| { | ||
| struct select_cpu_vtime *skel; | ||
| struct bpf_link *link; | ||
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| libbpf_set_strict_mode(LIBBPF_STRICT_ALL); | ||
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| skel = select_cpu_vtime__open_and_load(); | ||
| SCX_BUG_ON(!skel, "Failed to open and load skel"); | ||
|
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| SCX_ASSERT(!skel->bss->consumed); | ||
|
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| link = bpf_map__attach_struct_ops(skel->maps.select_cpu_vtime_ops); | ||
| SCX_BUG_ON(!link, "Failed to attach struct_ops"); | ||
|
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| sleep(1); | ||
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| SCX_ASSERT(skel->bss->consumed); | ||
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| bpf_link__destroy(link); | ||
| select_cpu_vtime__destroy(skel); | ||
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| return 0; | ||
| } |