xref: /linux/tools/sched_ext/scx_qmap.h (revision 0eaed89c18aeedf0898baf2dbf5ff027c6795152)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3  * Shared definitions between scx_qmap.bpf.c and scx_qmap.c.
4  *
5  * The scheduler keeps all state in a single BPF arena map. struct
6  * qmap_arena is the one object that lives at the base of the arena and is
7  * mmap'd into userspace so the loader can read counters directly.
8  *
9  * Copyright (c) 2026 Meta Platforms, Inc. and affiliates.
10  * Copyright (c) 2026 Tejun Heo <tj@kernel.org>
11  */
12 #ifndef __SCX_QMAP_H
13 #define __SCX_QMAP_H
14 
15 #ifdef __BPF__
16 #include <scx/bpf_arena_common.bpf.h>
17 #else
18 #include <linux/types.h>
19 #include <scx/bpf_arena_common.h>
20 #endif
21 
22 #define MAX_SUB_SCHEDS		8
23 
24 /*
25  * cpu_ctxs[] is sized to a fixed cap so the layout is shared between BPF and
26  * userspace. Keep this in sync with NR_CPUS used by the BPF side.
27  */
28 #define SCX_QMAP_MAX_CPUS	1024
29 
30 struct cpu_ctx {
31 	__u64 dsp_idx;		/* dispatch index */
32 	__u64 dsp_cnt;		/* remaining count */
33 	__u32 avg_weight;
34 	__u32 cpuperf_target;
35 };
36 
37 /* Opaque to userspace; defined in scx_qmap.bpf.c. */
38 struct task_ctx;
39 
40 struct qmap_fifo {
41 	struct task_ctx __arena *head;
42 	struct task_ctx __arena *tail;
43 	__s32 idx;
44 };
45 
46 struct qmap_arena {
47 	/* userspace-visible stats */
48 	__u64 nr_enqueued, nr_dispatched, nr_reenqueued, nr_reenqueued_cid0;
49 	__u64 nr_dequeued, nr_ddsp_from_enq;
50 	__u64 nr_core_sched_execed;
51 	__u64 nr_expedited_local, nr_expedited_remote;
52 	__u64 nr_expedited_lost, nr_expedited_from_timer;
53 	__u64 nr_highpri_queued;
54 	__u32 test_error_cnt;
55 	__u32 cpuperf_min, cpuperf_avg, cpuperf_max;
56 	__u32 cpuperf_target_min, cpuperf_target_avg, cpuperf_target_max;
57 
58 	/* kernel-side runtime state */
59 	__u64 sub_sched_cgroup_ids[MAX_SUB_SCHEDS];
60 	__u64 core_sched_head_seqs[5];
61 	__u64 core_sched_tail_seqs[5];
62 
63 	struct cpu_ctx cpu_ctxs[SCX_QMAP_MAX_CPUS];
64 
65 	/* task_ctx slab; allocated and threaded by qmap_init() */
66 	struct task_ctx __arena *task_ctxs;
67 	struct task_ctx __arena *task_free_head;
68 
69 	/* five priority FIFOs, each a doubly-linked list through task_ctx */
70 	struct qmap_fifo fifos[5];
71 };
72 
73 #endif /* __SCX_QMAP_H */
74