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Kernel: Don't log profile data before/after the process/thread lifetime

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There were a few cases where we could end up logging profiling events
before or after the associated process or thread exists in the profile:

After enabling profiling we might end up with CPU samples before we
had a chance to synthesize process/thread creation events.

After a thread exits we would still log associated kmalloc/kfree
events. Instead we now just ignore those events.
This commit is contained in:
Gunnar Beutner 2021-05-30 16:24:53 +02:00 committed by Andreas Kling
parent d24dd7a3df
commit 01c75e3a34
Notes: sideshowbarker 2024-07-18 17:09:16 +09:00 
Author: https://github.com/gunnarbeutner
Commit: https://github.com/SerenityOS/serenity/commit/01c75e3a34c
Pull-request: https://github.com/SerenityOS/serenity/pull/7592
8 changed files with 39 additions and 22 deletions
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20
Kernel/Heap/kmalloc.cpp
View file

@ -257,11 +257,11 @@ void* kmalloc(size_t size)
PANIC("kmalloc: Out of memory (requested size: {})", size);
}
Process* current_process = Process::current();
if (!current_process && Scheduler::colonel_initialized())
current_process = Scheduler::colonel();
if (current_process)
PerformanceManager::add_kmalloc_perf_event(*current_process, size, (FlatPtr)ptr);
Thread* current_thread = Thread::current();
if (!current_thread)
current_thread = Processor::idle_thread();
if (current_thread)
PerformanceManager::add_kmalloc_perf_event(*current_thread, size, (FlatPtr)ptr);
return ptr;
}
@ -277,11 +277,11 @@ void kfree(void* ptr)
++g_nested_kfree_calls;
if (g_nested_kfree_calls == 1) {
Process* current_process = Process::current();
if (!current_process && Scheduler::colonel_initialized())
current_process = Scheduler::colonel();
if (current_process)
PerformanceManager::add_kfree_perf_event(*current_process, 0, (FlatPtr)ptr);
Thread* current_thread = Thread::current();
if (!current_thread)
current_thread = Processor::idle_thread();
if (current_thread)
PerformanceManager::add_kfree_perf_event(*current_thread, 0, (FlatPtr)ptr);
}
g_kmalloc_global->m_heap.deallocate(ptr);

22
Kernel/PerformanceManager.h
View file

@ -40,6 +40,8 @@ public:
inline static void add_thread_created_event(Thread& thread)
{
if (thread.is_profiling_suppressed())
return;
if (auto* event_buffer = thread.process().current_perf_events_buffer()) {
[[maybe_unused]] auto rc = event_buffer->append(PERF_EVENT_THREAD_CREATE, thread.tid().value(), 0, nullptr, &thread);
}
@ -47,6 +49,8 @@ public:
inline static void add_thread_exit_event(Thread& thread)
{
// As an exception this doesn't check whether profiling is suppressed for
// the thread so we can record the thread_exit event anyway.
if (auto* event_buffer = thread.process().current_perf_events_buffer()) {
[[maybe_unused]] auto rc = event_buffer->append(PERF_EVENT_THREAD_EXIT, thread.tid().value(), 0, nullptr, &thread);
}
@ -54,6 +58,8 @@ public:
inline static void add_cpu_sample_event(Thread& current_thread, const RegisterState& regs, u32 lost_time)
{
if (current_thread.is_profiling_suppressed())
return;
if (auto* event_buffer = current_thread.process().current_perf_events_buffer()) {
[[maybe_unused]] auto rc = event_buffer->append_with_eip_and_ebp(
current_thread.pid(), current_thread.tid(),
@ -77,27 +83,35 @@ public:
inline static void add_context_switch_perf_event(Thread& current_thread, Thread& next_thread)
{
if (current_thread.is_profiling_suppressed())
return;
if (auto* event_buffer = current_thread.process().current_perf_events_buffer()) {
[[maybe_unused]] auto res = event_buffer->append(PERF_EVENT_CONTEXT_SWITCH, next_thread.pid().value(), next_thread.tid().value(), nullptr);
}
}
inline static void add_kmalloc_perf_event(Process& current_process, size_t size, FlatPtr ptr)
inline static void add_kmalloc_perf_event(Thread& current_thread, size_t size, FlatPtr ptr)
{
if (auto* event_buffer = current_process.current_perf_events_buffer()) {
if (current_thread.is_profiling_suppressed())
return;
if (auto* event_buffer = current_thread.process().current_perf_events_buffer()) {
[[maybe_unused]] auto res = event_buffer->append(PERF_EVENT_KMALLOC, size, ptr, nullptr);
}
}
inline static void add_kfree_perf_event(Process& current_process, size_t size, FlatPtr ptr)
inline static void add_kfree_perf_event(Thread& current_thread, size_t size, FlatPtr ptr)
{
if (auto* event_buffer = current_process.current_perf_events_buffer()) {
if (current_thread.is_profiling_suppressed())
return;
if (auto* event_buffer = current_thread.process().current_perf_events_buffer()) {
[[maybe_unused]] auto res = event_buffer->append(PERF_EVENT_KFREE, size, ptr, nullptr);
}
}
inline static void add_page_fault_event(Thread& thread, const RegisterState& regs)
{
if (thread.is_profiling_suppressed())
return;
if (auto* event_buffer = thread.process().current_perf_events_buffer()) {
[[maybe_unused]] auto rc = event_buffer->append_with_eip_and_ebp(
thread.pid(), thread.tid(),

5
Kernel/Scheduler.cpp
View file

@ -445,11 +445,6 @@ void Scheduler::prepare_for_idle_loop()
scheduler_data.m_in_scheduler = true;
}
bool Scheduler::colonel_initialized()
{
return !!s_colonel_process;
}
Process* Scheduler::colonel()
{
VERIFY(s_colonel_process);

1
Kernel/Scheduler.h
View file

@ -43,7 +43,6 @@ public:
static void leave_on_first_switch(u32 flags);
static void prepare_after_exec();
static void prepare_for_idle_loop();
static bool colonel_initialized();
static Process* colonel();
static void idle_loop(void*);
static void invoke_async();

1
Kernel/Syscalls/exit.cpp
View file

@ -19,6 +19,7 @@ void Process::sys$exit(int status)
}
auto* current_thread = Thread::current();
current_thread->set_profiling_suppressed();
PerformanceManager::add_thread_exit_event(*current_thread);
die();

6
Kernel/Syscalls/profiling.cpp
View file

@ -25,7 +25,7 @@ KResultOr<int> Process::sys$profiling_enable(pid_t pid, u64 event_mask)
if (!is_superuser())
return EPERM;
ScopedCritical critical;
g_profiling_event_mask = event_mask;
g_profiling_event_mask = PERF_EVENT_PROCESS_CREATE | PERF_EVENT_THREAD_CREATE | PERF_EVENT_MMAP;
if (g_global_perf_events)
g_global_perf_events->clear();
else
@ -40,6 +40,7 @@ KResultOr<int> Process::sys$profiling_enable(pid_t pid, u64 event_mask)
PerformanceManager::add_process_created_event(process);
return IterationDecision::Continue;
});
g_profiling_event_mask = event_mask;
return 0;
}
@ -51,12 +52,13 @@ KResultOr<int> Process::sys$profiling_enable(pid_t pid, u64 event_mask)
return ESRCH;
if (!is_superuser() && process->uid() != euid())
return EPERM;
g_profiling_event_mask = event_mask;
g_profiling_event_mask = PERF_EVENT_PROCESS_CREATE | PERF_EVENT_THREAD_CREATE | PERF_EVENT_MMAP;
process->set_profiling(true);
if (!process->create_perf_events_buffer_if_needed()) {
process->set_profiling(false);
return ENOMEM;
}
g_profiling_event_mask = event_mask;
if (!TimeManagement::the().enable_profile_timer()) {
process->set_profiling(false);
return ENOTSUP;

1
Kernel/Syscalls/thread.cpp
View file

@ -88,6 +88,7 @@ void Process::sys$exit_thread(Userspace<void*> exit_value, Userspace<void*> stac
}
auto current_thread = Thread::current();
current_thread->set_profiling_suppressed();
PerformanceManager::add_thread_exit_event(*current_thread);
if (stack_location) {

5
Kernel/Thread.h
View file

@ -1131,6 +1131,9 @@ public:
return m_nested_profiler_calls.fetch_sub(1, AK::MemoryOrder::memory_order_acquire);
}
bool is_profiling_suppressed() const { return m_is_profiling_suppressed; }
void set_profiling_suppressed() { m_is_profiling_suppressed = true; }
private:
Thread(NonnullRefPtr<Process>, NonnullOwnPtr<Region>, NonnullRefPtr<Timer>);
@ -1273,6 +1276,8 @@ private:
RefPtr<Timer> m_block_timer;
bool m_is_profiling_suppressed { false };
void yield_without_holding_big_lock();
void donate_without_holding_big_lock(RefPtr<Thread>&, const char*);
void yield_while_not_holding_big_lock();