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/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
* Copyright (c) 2024 David Vernet <dvernet@meta.com>
*/
#include <bpf/bpf.h>
#include <sched.h>
#include <scx/common.h>
#include <sched.h>
#include <sys/wait.h>
#include <unistd.h>
#include "hotplug_test.h"
#include "hotplug.bpf.skel.h"
#include "scx_test.h"
#include "util.h"
const char *online_path = "/sys/devices/system/cpu/cpu1/online";
static bool is_cpu_online(void)
{
return file_read_long(online_path) > 0;
}
static void toggle_online_status(bool online)
{
long val = online ? 1 : 0;
int ret;
ret = file_write_long(online_path, val);
if (ret != 0)
fprintf(stderr, "Failed to bring CPU %s (%s)",
online ? "online" : "offline", strerror(errno));
}
static enum scx_test_status setup(void **ctx)
{
if (!is_cpu_online())
return SCX_TEST_SKIP;
return SCX_TEST_PASS;
}
static enum scx_test_status test_hotplug(bool onlining, bool cbs_defined)
{
struct hotplug *skel;
struct bpf_link *link;
long kind, code;
SCX_ASSERT(is_cpu_online());
skel = hotplug__open_and_load();
SCX_ASSERT(skel);
/* Testing the offline -> online path, so go offline before starting */
if (onlining)
toggle_online_status(0);
if (cbs_defined) {
kind = SCX_KIND_VAL(SCX_EXIT_UNREG_BPF);
code = SCX_ECODE_VAL(SCX_ECODE_ACT_RESTART) | HOTPLUG_EXIT_RSN;
if (onlining)
code |= HOTPLUG_ONLINING;
} else {
kind = SCX_KIND_VAL(SCX_EXIT_UNREG_KERN);
code = SCX_ECODE_VAL(SCX_ECODE_ACT_RESTART) |
SCX_ECODE_VAL(SCX_ECODE_RSN_HOTPLUG);
}
if (cbs_defined)
link = bpf_map__attach_struct_ops(skel->maps.hotplug_cb_ops);
else
link = bpf_map__attach_struct_ops(skel->maps.hotplug_nocb_ops);
if (!link) {
SCX_ERR("Failed to attach scheduler");
hotplug__destroy(skel);
return SCX_TEST_FAIL;
}
toggle_online_status(onlining ? 1 : 0);
while (!UEI_EXITED(skel, uei))
sched_yield();
SCX_EQ(skel->data->uei.kind, kind);
SCX_EQ(UEI_REPORT(skel, uei), code);
if (!onlining)
toggle_online_status(1);
bpf_link__destroy(link);
hotplug__destroy(skel);
return SCX_TEST_PASS;
}
static enum scx_test_status test_hotplug_attach(void)
{
struct hotplug *skel;
struct bpf_link *link;
enum scx_test_status status = SCX_TEST_PASS;
long kind, code;
SCX_ASSERT(is_cpu_online());
SCX_ASSERT(scx_hotplug_seq() > 0);
skel = SCX_OPS_OPEN(hotplug_nocb_ops, hotplug);
SCX_ASSERT(skel);
SCX_OPS_LOAD(skel, hotplug_nocb_ops, hotplug, uei);
/*
* Take the CPU offline to increment the global hotplug seq, which
* should cause attach to fail due to us setting the hotplug seq above
*/
toggle_online_status(0);
link = bpf_map__attach_struct_ops(skel->maps.hotplug_nocb_ops);
toggle_online_status(1);
SCX_ASSERT(link);
while (!UEI_EXITED(skel, uei))
sched_yield();
kind = SCX_KIND_VAL(SCX_EXIT_UNREG_KERN);
code = SCX_ECODE_VAL(SCX_ECODE_ACT_RESTART) |
SCX_ECODE_VAL(SCX_ECODE_RSN_HOTPLUG);
SCX_EQ(skel->data->uei.kind, kind);
SCX_EQ(UEI_REPORT(skel, uei), code);
bpf_link__destroy(link);
hotplug__destroy(skel);
return status;
}
static enum scx_test_status run(void *ctx)
{
#define HP_TEST(__onlining, __cbs_defined) ({ \
if (test_hotplug(__onlining, __cbs_defined) != SCX_TEST_PASS) \
return SCX_TEST_FAIL; \
})
HP_TEST(true, true);
HP_TEST(false, true);
HP_TEST(true, false);
HP_TEST(false, false);
#undef HP_TEST
return test_hotplug_attach();
}
static void cleanup(void *ctx)
{
toggle_online_status(1);
}
struct scx_test hotplug_test = {
.name = "hotplug",
.description = "Verify hotplug behavior",
.setup = setup,
.run = run,
.cleanup = cleanup,
};
REGISTER_SCX_TEST(&hotplug_test)
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