Disable GC inside coroutines on mac OS

This commit is contained in:
Yorick van Pelt 2023-02-03 17:50:01 +01:00
parent 0fd8f542a8
commit eaeb994d8b
No known key found for this signature in database
GPG key ID: A36E70F9DC014A15
4 changed files with 74 additions and 5 deletions

View file

@ -326,6 +326,20 @@ static Symbol getName(const AttrName & name, EvalState & state, Env & env)
}
class BoehmDisableGC : public DisableGC {
public:
BoehmDisableGC() {
#if HAVE_BOEHMGC
GC_disable();
#endif
};
virtual ~BoehmDisableGC() override {
#if HAVE_BOEHMGC
GC_enable();
#endif
};
};
static bool gcInitialised = false;
void initGC()
@ -349,6 +363,12 @@ void initGC()
StackAllocator::defaultAllocator = &boehmGCStackAllocator;
/* Used to disable GC when entering coroutines on macOS */
DisableGC::create = []() {
return std::dynamic_pointer_cast<DisableGC>(std::make_shared<BoehmDisableGC>());
};
/* Set the initial heap size to something fairly big (25% of
physical RAM, up to a maximum of 384 MiB) so that in most cases
we don't need to garbage collect at all. (Collection has a

View file

@ -25,6 +25,7 @@ namespace nix {
// Generate 2 objects, discard one, run gc,
// see if one got collected and the other didn't
// GC is disabled inside coroutines on __APPLE__
static void testFinalizerCalls() {
bool* do_collect_collected = uncollectable_bool();
bool* dont_collect_collected = uncollectable_bool();
@ -37,7 +38,9 @@ namespace nix {
GC_gcollect();
GC_invoke_finalizers();
#if !__APPLE__
ASSERT_TRUE(*do_collect_collected);
#endif
ASSERT_FALSE(*dont_collect_collected);
ASSERT_NE(nullptr, dont_collect);
}
@ -58,6 +61,10 @@ namespace nix {
}
auto source = sinkToSource([&](Sink& sink) {
#if __APPLE__
ASSERT_TRUE(GC_is_disabled());
#endif
testFinalizerCalls();
bool* dont_collect_inner_collected = uncollectable_bool();
@ -71,6 +78,9 @@ namespace nix {
}
// pass control to main
writeString("foo", sink);
#if __APPLE__
ASSERT_TRUE(GC_is_disabled());
#endif
ASSERT_TRUE(*do_collect_inner_collected);
ASSERT_FALSE(*dont_collect_inner_collected);
@ -84,6 +94,7 @@ namespace nix {
std::string foo = readString(*source);
ASSERT_EQ(foo, "foo");
ASSERT_FALSE(GC_is_disabled());
GC_gcollect();
GC_invoke_finalizers();

View file

@ -186,6 +186,10 @@ static DefaultStackAllocator defaultAllocatorSingleton;
StackAllocator *StackAllocator::defaultAllocator = &defaultAllocatorSingleton;
std::shared_ptr<DisableGC> (*DisableGC::create)() = []() {
return std::dynamic_pointer_cast<DisableGC>(std::make_shared<DisableGC>());
};
std::unique_ptr<FinishSink> sourceToSink(std::function<void(Source &)> fun)
{
struct SourceToSink : FinishSink
@ -206,7 +210,11 @@ std::unique_ptr<FinishSink> sourceToSink(std::function<void(Source &)> fun)
if (in.empty()) return;
cur = in;
if (!coro)
if (!coro) {
#if __APPLE__
/* Disable GC when entering the coroutine on macOS, since it doesn't find the main thread stack in this case */
auto disablegc = DisableGC::create();
#endif
coro = coro_t::push_type(VirtualStackAllocator{}, [&](coro_t::pull_type & yield) {
LambdaSource source([&](char *out, size_t out_len) {
if (cur.empty()) {
@ -223,17 +231,28 @@ std::unique_ptr<FinishSink> sourceToSink(std::function<void(Source &)> fun)
});
fun(source);
});
}
if (!*coro) { abort(); }
if (!cur.empty()) (*coro)(false);
if (!cur.empty()) {
#if __APPLE__
auto disablegc = DisableGC::create();
#endif
(*coro)(false);
}
}
void finish() override
{
if (!coro) return;
if (!*coro) abort();
{
#if __APPLE__
auto disablegc = DisableGC::create();
#endif
(*coro)(true);
}
if (*coro) abort();
}
};
@ -264,18 +283,27 @@ std::unique_ptr<Source> sinkToSource(
size_t read(char * data, size_t len) override
{
if (!coro)
if (!coro) {
#if __APPLE__
auto disablegc = DisableGC::create();
#endif
coro = coro_t::pull_type(VirtualStackAllocator{}, [&](coro_t::push_type & yield) {
LambdaSink sink([&](std::string_view data) {
if (!data.empty()) yield(std::string(data));
});
fun(sink);
});
}
if (!*coro) { eof(); abort(); }
if (pos == cur.size()) {
if (!cur.empty()) (*coro)();
if (!cur.empty()) {
#if __APPLE__
auto disablegc = DisableGC::create();
#endif
(*coro)();
}
cur = coro->get();
pos = 0;
}

View file

@ -501,4 +501,14 @@ struct StackAllocator {
static StackAllocator *defaultAllocator;
};
/* Disabling GC when entering a coroutine (on macos).
::create is to avoid boehm gc dependency in libutil.
*/
class DisableGC {
public:
DisableGC() {};
virtual ~DisableGC() {};
static std::shared_ptr<DisableGC> (*create)();
};
}