From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ed1-f70.google.com (mail-ed1-f70.google.com [209.85.208.70]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 971655013A9 for ; Wed, 30 Sep 2026 14:24:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.208.70 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790778270; cv=none; b=WzaTmzrRvk2eRlIRnDbF6a3ZlPwU6Kx8PdSp2NFAAGk+VEwT2uP4xOpXpEJmdJGPrMZxz76aQO4cAxQegHx4DbPrS98OkbqS1XdNotyKZ1p/W1QApjIU3DZGUJthTTHm4OAfbxb9sjRY92fr67fJHRtWvd0qG8vfnssemXD1kxM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790778270; c=relaxed/simple; bh=wrN+6Ilm4vcEZ2BG8e5Iyxses/TGZ/d6MOMGwHZgZrc=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=hU9jeqoC8NEYielj5ul2iPPcDmvlSziL7PclBt5+x++BqP5kIbnL0ACIpAGn6G4ZKmCEd+N4jxlF4EO3aMJtkfV8odXjiijGK5GJuHcF8VXPWKeyLzcTn3JPjn2yIUGto6jrKSJlc3HqgnJ2XL5QmVwi/5MYHaiLGJGWXCPZacs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--jpiecuch.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=WVkg7eHW; arc=none smtp.client-ip=209.85.208.70 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--jpiecuch.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="WVkg7eHW" Received: by mail-ed1-f70.google.com with SMTP id 4fb4d7f45d1cf-6a91d818528so6245324a12.3 for ; Wed, 30 Sep 2026 07:24:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1790778256; x=1791383056; darn=vger.kernel.org; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:from:to:cc:subject:date:message-id:reply-to :content-type; bh=EjOSFrug7BNcg74vWN3jeDym65QUN+dalpdPxeDKCCo=; b=WVkg7eHWlcNcFfH0iPjoNMHnwZfmoQNEuwgFziHMMsK5e/C8b3CknLkAy3upjmqAna 4U+tAFq2S0xFEEfQ4pbsUuM82iEt2qtdLDCQvdmT9km1vJxiIIxoHHeRSjOlsEBDCgL7 6fKf8TzsiPQhhvRsewbTTIku8FyP7pat194nF4n2V+Q0DmnkoIQDVr1dtSgm7Y460Ub+ KDPhS48koF2Xvub6CdNTdvZoGGR/+ngUAgdsW7Kv8lv/RS4JiNgE1DPrDdqHZK8M/Rc7 hQaRha0cJPtKt42tcvjeCk2KmxsFmvP7R0iuFV78vttnYUg6bqmg/bXUb+bgiheIBDrM IdiQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1790778256; x=1791383056; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=EjOSFrug7BNcg74vWN3jeDym65QUN+dalpdPxeDKCCo=; b=Zm5kHfI+qPonulPNy6EbcseWvvkMLXpVn0cPHvtEzIqqQpVeKEsyAj5LEAy0Hof4JH jZJy2VWkzgWHKxGBEOTeAUoGprySityKuqJztUq31pG2wZCcYVSNU4hB5WYBVloFQoSS nqXWHvTaZXi2+EKTLJGuxJNvxFoIVZc8d/4+wQvy0sjmro7d6I4EGaSh7nz+ti2Ep4TB 6S4sBW+3Zs9INzrGt0i0jQClvkdG8EBxSbxb1llQhb1EtYKbQEpCi2K2z/JX7TY25jLO DRsJ+pydxlYlPvb9nZiFnyAcCpOyMyAwpw99/Aohen8+NMzZpva87pJgCjmVqd1u1aa7 0gag== X-Forwarded-Encrypted: i=1; AKwUvBzcXKnq2Z4M4Cl36qqfk9ZSV209UJWXZT9Q1BScynbFSfsDPp8qmlMR5ISzDp6Ewvoe9jzNMewHyCgSwh0=@vger.kernel.org X-Gm-Message-State: AFq9FYLU3e2L5Uob1lKeRG/jNApg+2L524aSaLKpf+8Q9fpkjn7o/D6T g6ceF0SvxqS6TYOekOyfQ0PIbvlglF8H50JmhZN2DB9HZsyIKKoctBloAj0amxwU0I75UfUgsnd bJnJquK2aNP8muw== X-Received: from edsl22.prod.google.com ([2002:aa7:d956:0:b0:6ae:185d:7804]) (user=jpiecuch job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6402:27d0:b0:6ac:6d97:c5fa with SMTP id 4fb4d7f45d1cf-6ae199241d8mr1243291a12.25.1790778255900; Wed, 30 Sep 2026 07:24:15 -0700 (PDT) Date: Wed, 30 Sep 2026 14:23:59 +0000 In-Reply-To: <20260930142412.552765-1-jpiecuch@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260930142412.552765-1-jpiecuch@google.com> X-Mailer: git-send-email 2.56.0.rc1.315.gc6ed9934b7-goog Message-ID: <20260930142412.552765-3-jpiecuch@google.com> Subject: [PATCH v3 2/2] selftests/sched_ext: Add a test for ops.dequeue() on remote local DSQ moves From: Kuba Piecuch To: Tejun Heo , David Vernet , Andrea Righi , Changwoo Min Cc: Kuba Piecuch , Emil Tsalapatis , sched-ext@lists.linux.dev, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Add a dequeue_remote test that makes moves of tasks in the BPF scheduler's custody to another CPU's local DSQ the common case, both via SCX_DSQ_LOCAL_ON dispatch and via scx_bpf_dsq_move_to_local(). The BPF scheduler tracks each task's custody state and triggers scx_bpf_error() if a custody period doesn't end with exactly one ops.dequeue() before the task runs, or if it ends with an SCX_DEQ_CORE_SCHED_EXEC dequeue of a task without a core cookie. Without the previous patch, the test fails with: sched_ext: dequeue_remote: dequeue_remote.bpf.c:141: 15 (rcu_preempt): late ops.dequeue() with SCX_DEQ_CORE_SCHED_EXEC (enq_cpu=3 cpu=2 seq=1) ... ops_dequeue+0x114/0x170 set_next_task_scx+0x104/0x1e0 __pick_next_task+0xc7/0x180 __schedule+0x154/0x1870 Reviewed-by: Andrea Righi Assisted-by: Claude:claude-opus-5.5 Signed-off-by: Kuba Piecuch --- tools/testing/selftests/sched_ext/Makefile | 1 + .../selftests/sched_ext/dequeue_remote.bpf.c | 270 ++++++++++++++++++ .../selftests/sched_ext/dequeue_remote.c | 204 +++++++++++++ 3 files changed, 475 insertions(+) create mode 100644 tools/testing/selftests/sched_ext/dequeue_remote.bpf.c create mode 100644 tools/testing/selftests/sched_ext/dequeue_remote.c diff --git a/tools/testing/selftests/sched_ext/Makefile b/tools/testing/selftests/sched_ext/Makefile index 4e06d0baaeec..af919a56a4f4 100644 --- a/tools/testing/selftests/sched_ext/Makefile +++ b/tools/testing/selftests/sched_ext/Makefile @@ -165,6 +165,7 @@ auto-test-targets := \ create_dsq \ dequeue \ dequeue_iter \ + dequeue_remote \ enq_last_no_enq_fails \ ddsp_bogus_dsq_fail \ ddsp_vtimelocal_fail \ diff --git a/tools/testing/selftests/sched_ext/dequeue_remote.bpf.c b/tools/testing/selftests/sched_ext/dequeue_remote.bpf.c new file mode 100644 index 000000000000..983590c6d498 --- /dev/null +++ b/tools/testing/selftests/sched_ext/dequeue_remote.bpf.c @@ -0,0 +1,270 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Verify that ops.dequeue() is called when a task leaves the BPF scheduler's + * custody by being moved to the local DSQ of a CPU other than the one whose + * rq it's on (move_remote_task_to_local_dsq()). + * + * ops.enqueue() puts every task into custody and ops.dispatch() moves it to + * the dispatching CPU's local DSQ, so most moves cross CPUs. With + * @test_use_move_to_local, tasks are queued on a user DSQ and consumed with + * scx_bpf_dsq_move_to_local(). Otherwise, they are queued in a BPF queue and + * dispatched with SCX_DSQ_LOCAL_ON. + * + * Copyright (c) 2026 Google LLC. + */ + +#include + +#define SHARED_DSQ 0 +#define MAX_DISPATCH_POPS 8 + +char _license[] SEC("license") = "GPL"; + +UEI_DEFINE(uei); + +struct { + __uint(type, BPF_MAP_TYPE_QUEUE); + __uint(max_entries, 32768); + __type(value, s32); +} global_queue SEC(".maps"); + +enum task_state { + TASK_NONE = 0, + TASK_ENQUEUED, /* in BPF custody, waiting for ops.dequeue() */ + TASK_DISPATCHED, /* left custody */ +}; + +struct task_ctx { + enum task_state state; + s32 enq_cpu; /* scx_bpf_task_cpu() at ops.enqueue() */ + u64 enqueue_seq; +}; + +struct { + __uint(type, BPF_MAP_TYPE_TASK_STORAGE); + __uint(map_flags, BPF_F_NO_PREALLOC); + __type(key, int); + __type(value, struct task_ctx); +} task_ctx_stor SEC(".maps"); + +/* core_cookie only exists with CONFIG_SCHED_CORE */ +struct task_struct___core_sched { + unsigned long core_cookie; +} __attribute__((preserve_access_index)); + +bool test_use_move_to_local; + +u64 enqueue_cnt, dequeue_cnt, dispatch_dequeue_cnt, change_dequeue_cnt; +u64 remote_dispatch_cnt, remote_running_cnt, missed_dequeue_cnt; +u64 core_sched_exec_dequeue_cnt; + +static struct task_ctx *lookup_task_ctx(struct task_struct *p) +{ + return bpf_task_storage_get(&task_ctx_stor, p, 0, 0); +} + +static bool task_has_core_cookie(struct task_struct *p) +{ + struct task_struct___core_sched *t = (void *)p; + + if (!bpf_core_field_exists(t->core_cookie)) + return false; + return BPF_CORE_READ(t, core_cookie); +} + +s32 BPF_STRUCT_OPS(dequeue_remote_select_cpu, struct task_struct *p, + s32 prev_cpu, u64 wake_flags) +{ + /* no direct dispatch, always go through ops.enqueue() */ + return prev_cpu; +} + +void BPF_STRUCT_OPS(dequeue_remote_enqueue, struct task_struct *p, u64 enq_flags) +{ + struct task_ctx *tctx; + s32 pid = p->pid; + + tctx = lookup_task_ctx(p); + if (!tctx) { + scx_bpf_dsq_insert(p, SCX_DSQ_GLOBAL, SCX_SLICE_DFL, enq_flags); + return; + } + + /* the previous custody period must have ended with ops.dequeue() */ + if (tctx->state == TASK_ENQUEUED) + scx_bpf_error("%d (%s): enqueue while in ENQUEUED state seq=%llu", + p->pid, p->comm, tctx->enqueue_seq); + + /* + * Mark @p as enqueued before making it visible to ops.dispatch() on + * other CPUs, which skips queue entries of tasks not in ENQUEUED + * state as stale. + */ + tctx->state = TASK_ENQUEUED; + tctx->enq_cpu = scx_bpf_task_cpu(p); + tctx->enqueue_seq++; + + if (test_use_move_to_local) { + scx_bpf_dsq_insert(p, SHARED_DSQ, SCX_SLICE_DFL, enq_flags); + } else if (bpf_map_push_elem(&global_queue, &pid, 0)) { + scx_bpf_dsq_insert(p, SCX_DSQ_GLOBAL, SCX_SLICE_DFL, enq_flags); + tctx->state = TASK_DISPATCHED; + tctx->enq_cpu = -1; + goto out; + } + + __sync_fetch_and_add(&enqueue_cnt, 1); +out: + scx_bpf_kick_cpu(scx_bpf_task_cpu(p), SCX_KICK_IDLE); +} + +void BPF_STRUCT_OPS(dequeue_remote_dequeue, struct task_struct *p, u64 deq_flags) +{ + struct task_ctx *tctx; + + __sync_fetch_and_add(&dequeue_cnt, 1); + + tctx = lookup_task_ctx(p); + if (!tctx) + return; + + /* + * Only core scheduling can pick a task straight out of custody, and + * only if the task has a core cookie. Otherwise, the custody exit was + * missed when @p was inserted into a local DSQ and got deferred until + * @p was picked. + */ + if ((deq_flags & SCX_DEQ_CORE_SCHED_EXEC) && !task_has_core_cookie(p)) { + __sync_fetch_and_add(&core_sched_exec_dequeue_cnt, 1); + scx_bpf_error("%d (%s): late ops.dequeue() with SCX_DEQ_CORE_SCHED_EXEC (enq_cpu=%d cpu=%d seq=%llu)", + p->pid, p->comm, tctx->enq_cpu, + scx_bpf_task_cpu(p), tctx->enqueue_seq); + } + + /* ops.dequeue() ends the custody period started by ops.enqueue() */ + if (tctx->state != TASK_ENQUEUED) + scx_bpf_error("%d (%s): dequeue outside custody deq_flags=0x%llx state=%d seq=%llu", + p->pid, p->comm, deq_flags, tctx->state, + tctx->enqueue_seq); + + if (deq_flags & SCX_DEQ_SCHED_CHANGE) { + __sync_fetch_and_add(&change_dequeue_cnt, 1); + tctx->state = TASK_NONE; + } else { + __sync_fetch_and_add(&dispatch_dequeue_cnt, 1); + tctx->state = TASK_DISPATCHED; + } +} + +void BPF_STRUCT_OPS(dequeue_remote_dispatch, s32 cpu, struct task_struct *prev) +{ + struct task_ctx *tctx; + struct task_struct *p; + s32 pid; + int i; + + if (test_use_move_to_local) { + scx_bpf_dsq_move_to_local(SHARED_DSQ, 0); + return; + } + + /* pop past stale entries so that they don't leave this CPU idle */ + bpf_for(i, 0, MAX_DISPATCH_POPS) { + if (bpf_map_pop_elem(&global_queue, &pid)) + return; + + p = bpf_task_from_pid(pid); + if (!p) + continue; + + /* + * Entries are stale if @p left custody through a property + * change dequeue or was dispatched from a duplicate entry. + */ + tctx = lookup_task_ctx(p); + if (!tctx || tctx->state != TASK_ENQUEUED) { + bpf_task_release(p); + continue; + } + + if (bpf_cpumask_test_cpu(cpu, p->cpus_ptr)) { + if (scx_bpf_task_cpu(p) != cpu) + __sync_fetch_and_add(&remote_dispatch_cnt, 1); + scx_bpf_dsq_insert(p, SCX_DSQ_LOCAL_ON | cpu, + SCX_SLICE_DFL, 0); + } else { + scx_bpf_dsq_insert(p, SCX_DSQ_GLOBAL, SCX_SLICE_DFL, 0); + } + + bpf_task_release(p); + return; + } + + /* out of pops with entries left, retry instead of idling this CPU */ + if (!bpf_map_peek_elem(&global_queue, &pid)) + scx_bpf_kick_cpu(cpu, SCX_KICK_IDLE); +} + +void BPF_STRUCT_OPS(dequeue_remote_running, struct task_struct *p) +{ + struct task_ctx *tctx; + + tctx = lookup_task_ctx(p); + if (!tctx) + return; + + /* tasks can only run from a local DSQ, i.e. after leaving custody */ + if (tctx->state == TASK_ENQUEUED) { + __sync_fetch_and_add(&missed_dequeue_cnt, 1); + scx_bpf_error("%d (%s): running without ops.dequeue() (enq_cpu=%d cpu=%d seq=%llu)", + p->pid, p->comm, tctx->enq_cpu, + scx_bpf_task_cpu(p), tctx->enqueue_seq); + return; + } + + if (tctx->enq_cpu >= 0 && tctx->enq_cpu != scx_bpf_task_cpu(p)) + __sync_fetch_and_add(&remote_running_cnt, 1); + tctx->enq_cpu = -1; +} + +s32 BPF_STRUCT_OPS(dequeue_remote_init_task, struct task_struct *p, + struct scx_init_task_args *args) +{ + struct task_ctx *tctx; + + tctx = bpf_task_storage_get(&task_ctx_stor, p, 0, + BPF_LOCAL_STORAGE_GET_F_CREATE); + if (!tctx) + return -ENOMEM; + + /* task storage persists across attachments, start from scratch */ + tctx->state = TASK_NONE; + tctx->enq_cpu = -1; + tctx->enqueue_seq = 0; + + return 0; +} + +s32 BPF_STRUCT_OPS_SLEEPABLE(dequeue_remote_init) +{ + return scx_bpf_create_dsq(SHARED_DSQ, -1); +} + +void BPF_STRUCT_OPS(dequeue_remote_exit, struct scx_exit_info *ei) +{ + UEI_RECORD(uei, ei); +} + +SEC(".struct_ops.link") +struct sched_ext_ops dequeue_remote_ops = { + .select_cpu = (void *)dequeue_remote_select_cpu, + .enqueue = (void *)dequeue_remote_enqueue, + .dequeue = (void *)dequeue_remote_dequeue, + .dispatch = (void *)dequeue_remote_dispatch, + .running = (void *)dequeue_remote_running, + .init_task = (void *)dequeue_remote_init_task, + .init = (void *)dequeue_remote_init, + .exit = (void *)dequeue_remote_exit, + .flags = SCX_OPS_ENQ_LAST, + .name = "dequeue_remote", +}; diff --git a/tools/testing/selftests/sched_ext/dequeue_remote.c b/tools/testing/selftests/sched_ext/dequeue_remote.c new file mode 100644 index 000000000000..f2c1901030de --- /dev/null +++ b/tools/testing/selftests/sched_ext/dequeue_remote.c @@ -0,0 +1,204 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Verify that ops.dequeue() is called for tasks leaving BPF custody through + * an SCX-internal cross-CPU migration (move_remote_task_to_local_dsq()). + * + * Copyright (c) 2026 Google LLC. + */ +#define _GNU_SOURCE +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include "scx_test.h" +#include "dequeue_remote.bpf.skel.h" + +#define MAX_WORKERS 64 +#define RUN_MS 2000 + +static int nr_cpus; + +static long long now_ms(void) +{ + struct timespec ts; + + clock_gettime(CLOCK_MONOTONIC, &ts); + return ts.tv_sec * 1000LL + ts.tv_nsec / 1000000; +} + +/* mix of short bursts and sleeps to generate lots of enqueues and wakeups */ +static void worker_fn(int id) +{ + long long end = now_ms() + RUN_MS; + volatile unsigned long sum = 0; + + while (now_ms() < end) { + unsigned long j; + + for (j = 0; j < 20000 + id * 1000; j++) + sum += j; + if (id & 1) + usleep(100); + else + sched_yield(); + } + + exit(0); +} + +static enum scx_test_status run_scenario(struct dequeue_remote *skel, + bool use_move_to_local, + const char *name) +{ + enum scx_test_status ret = SCX_TEST_PASS; + struct bpf_link *link; + pid_t pids[MAX_WORKERS]; + int nr_workers, nr_forked, i; + + nr_workers = 2 * nr_cpus; + if (nr_workers < 4) + nr_workers = 4; + if (nr_workers > MAX_WORKERS) + nr_workers = MAX_WORKERS; + + skel->bss->test_use_move_to_local = use_move_to_local; + skel->bss->enqueue_cnt = 0; + skel->bss->dequeue_cnt = 0; + skel->bss->dispatch_dequeue_cnt = 0; + skel->bss->change_dequeue_cnt = 0; + skel->bss->remote_dispatch_cnt = 0; + skel->bss->remote_running_cnt = 0; + skel->bss->missed_dequeue_cnt = 0; + skel->bss->core_sched_exec_dequeue_cnt = 0; + memset(&skel->data->uei, 0, sizeof(skel->data->uei)); + + link = bpf_map__attach_struct_ops(skel->maps.dequeue_remote_ops); + SCX_FAIL_IF(!link, "Failed to attach struct_ops for %s", name); + + fflush(stdout); + fflush(stderr); + + for (nr_forked = 0; nr_forked < nr_workers; nr_forked++) { + pid_t pid = fork(); + + if (pid < 0) { + SCX_ERR("Failed to fork worker %d", nr_forked); + ret = SCX_TEST_FAIL; + break; + } + if (pid == 0) + worker_fn(nr_forked); + pids[nr_forked] = pid; + } + + /* on failure, kill the remaining workers but still reap them */ + for (i = 0; i < nr_forked; i++) { + int status; + + if (ret != SCX_TEST_PASS) + kill(pids[i], SIGKILL); + + if (waitpid(pids[i], &status, 0) != pids[i]) { + SCX_ERR("Failed to wait for worker %d", i); + ret = SCX_TEST_FAIL; + } else if (ret == SCX_TEST_PASS && status != 0) { + SCX_ERR("Worker %d exited with status %d", i, status); + ret = SCX_TEST_FAIL; + } + } + + bpf_link__destroy(link); + + if (ret != SCX_TEST_PASS) + return ret; + + printf("%s:\n", name); + printf(" workers: %d\n", nr_workers); + printf(" enqueues: %lu\n", (unsigned long)skel->bss->enqueue_cnt); + printf(" dequeues: %lu (dispatch: %lu, property_change: %lu)\n", + (unsigned long)skel->bss->dequeue_cnt, + (unsigned long)skel->bss->dispatch_dequeue_cnt, + (unsigned long)skel->bss->change_dequeue_cnt); + if (!use_move_to_local) + printf(" remote SCX_DSQ_LOCAL_ON dispatches: %lu\n", + (unsigned long)skel->bss->remote_dispatch_cnt); + printf(" ran on a CPU other than the enqueue CPU: %lu\n", + (unsigned long)skel->bss->remote_running_cnt); + printf(" ran without ops.dequeue(): %lu\n", + (unsigned long)skel->bss->missed_dequeue_cnt); + printf(" late SCX_DEQ_CORE_SCHED_EXEC dequeues: %lu\n", + (unsigned long)skel->bss->core_sched_exec_dequeue_cnt); + + if (skel->data->uei.kind != EXIT_KIND(SCX_EXIT_UNREG)) + SCX_ERR("Scheduler exited with kind=%lld: %s", + (long long)skel->data->uei.kind, skel->data->uei.msg); + SCX_EQ(skel->data->uei.kind, EXIT_KIND(SCX_EXIT_UNREG)); + + /* the test is meaningless if no task was moved across CPUs */ + SCX_GT(skel->bss->remote_running_cnt, 0); + SCX_EQ(skel->bss->enqueue_cnt, skel->bss->dequeue_cnt); + + return SCX_TEST_PASS; +} + +static enum scx_test_status setup(void **ctx) +{ + struct dequeue_remote *skel; + cpu_set_t cpus; + + SCX_FAIL_IF(sched_getaffinity(0, sizeof(cpus), &cpus), + "Failed to get CPU affinity"); + nr_cpus = CPU_COUNT(&cpus); + if (nr_cpus < 2) { + fprintf(stderr, "Skipping: requires at least 2 usable CPUs\n"); + return SCX_TEST_SKIP; + } + + skel = SCX_OPS_OPEN(dequeue_remote_ops, dequeue_remote); + SCX_OPS_LOAD(skel, dequeue_remote_ops, dequeue_remote, uei); + + *ctx = skel; + + return SCX_TEST_PASS; +} + +static enum scx_test_status run(void *ctx) +{ + struct dequeue_remote *skel = ctx; + enum scx_test_status status; + + status = run_scenario(skel, false, + "BPF queue -> SCX_DSQ_LOCAL_ON | cpu"); + if (status != SCX_TEST_PASS) + return status; + + status = run_scenario(skel, true, + "user DSQ -> scx_bpf_dsq_move_to_local()"); + if (status != SCX_TEST_PASS) + return status; + + return SCX_TEST_PASS; +} + +static void cleanup(void *ctx) +{ + struct dequeue_remote *skel = ctx; + + dequeue_remote__destroy(skel); +} + +struct scx_test dequeue_remote_test = { + .name = "dequeue_remote", + .description = "Verify ops.dequeue() on SCX-internal cross-CPU migrations", + .setup = setup, + .run = run, + .cleanup = cleanup, +}; + +REGISTER_SCX_TEST(&dequeue_remote_test) -- 2.56.0.rc1.315.gc6ed9934b7-goog