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Revert "Disable GC during coroutine execution + test"

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Théophane Hufschmitt 2023-03-08 20:47:52 +01:00 • committed by GitHub
parent e8415dc439
commit 39700c5cbe
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6 changed files with 9 additions and 232 deletions
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25
src/libexpr/eval.cc
View file

@ -325,22 +325,6 @@ static Symbol getName(const AttrName & name, EvalState & state, Env & env)
}
}
#if HAVE_BOEHMGC
/* Disable GC while this object lives. Used by CoroutineContext.
*
* Boehm keeps a count of GC_disable() and GC_enable() calls,
* and only enables GC when the count matches.
*/
class BoehmDisableGC {
public:
BoehmDisableGC() {
GC_disable();
};
~BoehmDisableGC() {
GC_enable();
};
};
#endif
static bool gcInitialised = false;
@ -365,15 +349,6 @@ void initGC()
StackAllocator::defaultAllocator = &boehmGCStackAllocator;
#if NIX_BOEHM_PATCH_VERSION != 1
printTalkative("Unpatched BoehmGC, disabling GC inside coroutines");
/* Used to disable GC when entering coroutines on macOS */
create_coro_gc_hook = []() -> std::shared_ptr<void> {
return std::make_shared<BoehmDisableGC>();
};
#endif
/* 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

147
src/libexpr/tests/coro-gc.cc
View file

@ -1,147 +0,0 @@
#include <gtest/gtest.h>
#if HAVE_BOEHMGC
#include <gc/gc.h>
#include "eval.hh"
#include "serialise.hh"
#endif
namespace nix {
#if HAVE_BOEHMGC
static void finalizer(void *obj, void *data) {
*((bool*)data) = true;
}
static bool* make_witness(volatile void* obj) {
/* We can't store the witnesses on the stack,
since they might be collected long afterwards */
bool* res = (bool*)GC_MALLOC_UNCOLLECTABLE(1);
*res = false;
GC_register_finalizer((void*)obj, finalizer, res, nullptr, nullptr);
return res;
}
// 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() {
volatile void* do_collect = GC_MALLOC_ATOMIC(128);
volatile void* dont_collect = GC_MALLOC_ATOMIC(128);
bool* do_collect_witness = make_witness(do_collect);
bool* dont_collect_witness = make_witness(dont_collect);
GC_gcollect();
GC_invoke_finalizers();
ASSERT_TRUE(GC_is_disabled() || *do_collect_witness);
ASSERT_FALSE(*dont_collect_witness);
ASSERT_NE(nullptr, dont_collect);
}
TEST(CoroGC, BasicFinalizers) {
initGC();
testFinalizerCalls();
}
// Run testFinalizerCalls inside a coroutine
// this tests that GC works as expected inside a coroutine
TEST(CoroGC, CoroFinalizers) {
initGC();
auto source = sinkToSource([&](Sink& sink) {
testFinalizerCalls();
// pass control to main
writeString("foo", sink);
});
// pass control to coroutine
std::string foo = readString(*source);
ASSERT_EQ(foo, "foo");
}
#if __APPLE__
// This test tests that GC is disabled on darwin
// to work around the patch not being sufficient there,
// causing crashes whenever gc is invoked inside a coroutine
TEST(CoroGC, AppleCoroDisablesGC) {
initGC();
auto source = sinkToSource([&](Sink& sink) {
ASSERT_TRUE(GC_is_disabled());
// pass control to main
writeString("foo", sink);
ASSERT_TRUE(GC_is_disabled());
// pass control to main
writeString("bar", sink);
});
// pass control to coroutine
std::string foo = readString(*source);
ASSERT_EQ(foo, "foo");
ASSERT_FALSE(GC_is_disabled());
// pass control to coroutine
std::string bar = readString(*source);
ASSERT_EQ(bar, "bar");
ASSERT_FALSE(GC_is_disabled());
}
#endif
// This test tests that boehm handles coroutine stacks correctly
// This test tests that coroutine stacks are registered to the GC,
// even when the coroutine is not running. It also tests that
// the main stack is still registered to the GC when the coroutine is running.
TEST(CoroGC, CoroutineStackNotGCd) {
initGC();
volatile void* do_collect = GC_MALLOC_ATOMIC(128);
volatile void* dont_collect = GC_MALLOC_ATOMIC(128);
bool* do_collect_witness = make_witness(do_collect);
bool* dont_collect_witness = make_witness(dont_collect);
do_collect = nullptr;
auto source = sinkToSource([&](Sink& sink) {
volatile void* dont_collect_inner = GC_MALLOC_ATOMIC(128);
volatile void* do_collect_inner = GC_MALLOC_ATOMIC(128);
bool* do_collect_inner_witness = make_witness(do_collect_inner);
bool* dont_collect_inner_witness = make_witness(dont_collect_inner);
do_collect_inner = nullptr;
// pass control to main
writeString("foo", sink);
ASSERT_FALSE(*dont_collect_inner_witness);
ASSERT_TRUE(*do_collect_inner_witness);
ASSERT_NE(nullptr, dont_collect_inner);
// pass control to main
writeString("bar", sink);
});
// pass control to coroutine
std::string foo = readString(*source);
ASSERT_EQ(foo, "foo");
ASSERT_FALSE(GC_is_disabled());
GC_gcollect();
GC_invoke_finalizers();
// pass control to coroutine
std::string bar = readString(*source);
ASSERT_EQ(bar, "bar");
ASSERT_FALSE(*dont_collect_witness);
ASSERT_TRUE(*do_collect_witness);
ASSERT_NE(nullptr, dont_collect);
}
#endif
}

2
src/libexpr/tests/local.mk
View file

@ -16,4 +16,4 @@ libexpr-tests_CXXFLAGS += -I src/libexpr -I src/libutil -I src/libstore -I src/l
libexpr-tests_LIBS = libstore-tests libutils-tests libexpr libutil libstore libfetchers
libexpr-tests_LDFLAGS := $(GTEST_LIBS) -lgmock -lboost_context
libexpr-tests_LDFLAGS := $(GTEST_LIBS) -lgmock