CpuRecorder may leak memory for destroyed threads

[overvenus]

Bug Report

CpuRecorder.thread_stats never get cleanup. It should remove threads that is not in _thread_stores.
Through it may not be a real problem as TiKV does not create and destroy threads frequently.

tikv/components/resource_metering/src/recorder/sub_recorder/cpu.rs

Lines 49 to 61 in 9b1a816

	fn cleanup(
	&mut self,
	_records: &mut RawRecords,
	_thread_stores: &mut HashMap<Pid, LocalStorage>,
	) {
	const THREAD_STAT_LEN_THRESHOLD: usize = 500;
	if self.thread_stats.capacity() > THREAD_STAT_LEN_THRESHOLD
	&& self.thread_stats.len() < THREAD_STAT_LEN_THRESHOLD / 2
	{
	self.thread_stats.shrink_to(THREAD_STAT_LEN_THRESHOLD);
	}
	}

What version of TiKV are you using?

v7.3.0