From a1cde0f881ee4865d38e2e6e88cc71dcd362fdd2 Mon Sep 17 00:00:00 2001 From: Lukas Larsson Date: Thu, 17 Mar 2016 11:15:54 +0100 Subject: erts: Deallocate heap fragments from trace nif calls Any heap fragment created during a nif call to a tracer nif should be free'd immediately in order for the GC not to treat it as live data. --- erts/emulator/beam/beam_emu.c | 2 +- erts/emulator/beam/erl_nif.c | 31 ++++++++++++++++++++++++++++--- 2 files changed, 29 insertions(+), 4 deletions(-) (limited to 'erts') diff --git a/erts/emulator/beam/beam_emu.c b/erts/emulator/beam/beam_emu.c index 7cb259cb8a..254bfe4ba0 100644 --- a/erts/emulator/beam/beam_emu.c +++ b/erts/emulator/beam/beam_emu.c @@ -3346,7 +3346,7 @@ do { \ OpCase(normal_exit): { SWAPOUT; c_p->freason = EXC_NORMAL; - c_p->arity = 0; /* In case this process will ever be garbed again. */ + c_p->arity = 0; /* In case this process will never be garbed again. */ ERTS_SMP_UNREQ_PROC_MAIN_LOCK(c_p); erts_do_exit_process(c_p, am_normal); ERTS_SMP_REQ_PROC_MAIN_LOCK(c_p); diff --git a/erts/emulator/beam/erl_nif.c b/erts/emulator/beam/erl_nif.c index 7ab5421c91..73c0eb8eba 100644 --- a/erts/emulator/beam/erl_nif.c +++ b/erts/emulator/beam/erl_nif.c @@ -92,11 +92,12 @@ static ERTS_INLINE Eterm* alloc_heap(ErlNifEnv* env, unsigned need) } static Eterm* alloc_heap_heavy(ErlNifEnv* env, unsigned need, Eterm* hp) -{ +{ env->hp = hp; - if (env->heap_frag == NULL) { + if (env->heap_frag == NULL) { ASSERT(HEAP_LIMIT(env->proc) == env->hp_end); - HEAP_TOP(env->proc) = env->hp; + ASSERT(env->hp + need > env->hp_end); + HEAP_TOP(env->proc) = env->hp; } else { env->heap_frag->used_size = hp - env->heap_frag->mem; @@ -3165,13 +3166,37 @@ Eterm erts_nif_call_function(Process *p, Process *tracee, || erts_smp_thr_progress_is_blocking()); #endif if (p) { + /* This is almost a normal nif call like in beam_emu, + except that any heap fragment created in the nif will be + discarded without checking if anything in it is live. + This is because we cannot do a GC here as we don't know + the number of live registers that have to be preserved. + This means that any heap part of the returned term may + not be used outside this function. */ struct enif_environment_t env; + ErlHeapFragment *orig_hf = MBUF(p); + ErlOffHeap orig_oh = MSO(p); ASSERT(is_internal_pid(p->common.id)); + MBUF(p) = NULL; + clear_offheap(&MSO(p)); + erts_pre_nif(&env, p, mod, tracee); nif_result = (*fun->fptr)(&env, argc, argv); if (env.exception_thrown) nif_result = THE_NON_VALUE; erts_post_nif(&env); + + /* Free any offheap and heap fragments created in nif */ + if (MSO(p).first) { + erts_cleanup_offheap(&MSO(p)); + clear_offheap(&MSO(p)); + } + if (MBUF(p)) + free_message_buffer(MBUF(p)); + + /* restore original heap fragment list */ + MBUF(p) = orig_hf; + MSO(p) = orig_oh; } else { /* Nif call was done without a process context, so we create a phony one. */ -- cgit v1.2.3