spinning on an atomic leaks memory when using jemalloc #1347
Description
When keeping spawning new threads doing this spin and exits, process RSS keeps going up and finally gets OOM killed when linking with jemalloc. libc malloc doesn't have this problem.
#include <atomic>
#include <thread>
#include <deque>
#include <chrono>
inline int do_spin(std::atomic<unsigned> & generation, unsigned int val)
{
for (;;)
if (generation.load(std::memory_order_relaxed) != val)
return 0;
}
int main(int argc, char *argv[]) {
std::atomic<unsigned> generation = 0;
for(;;) {
std::deque<std::thread> q;
for (auto i = 1u; i < 40; ++i) {
q.push_back(std::thread([&]() {
do_spin(generation, generation);
}));
}
using namespace std::chrono_literals;
std::this_thread::sleep_for(100ms);
generation ++;
for (auto & t : q) {
t.join();
}
}
}