diff options
Diffstat (limited to 'erts/emulator/beam/erl_nif.c')
-rw-r--r-- | erts/emulator/beam/erl_nif.c | 317 |
1 files changed, 183 insertions, 134 deletions
diff --git a/erts/emulator/beam/erl_nif.c b/erts/emulator/beam/erl_nif.c index 94ebf88b56..d2000aa71e 100644 --- a/erts/emulator/beam/erl_nif.c +++ b/erts/emulator/beam/erl_nif.c @@ -237,9 +237,11 @@ static void cache_env(ErlNifEnv* env); static void full_flush_env(ErlNifEnv *env); static void flush_env(ErlNifEnv* env); -/* Temporary object header, auto-deallocated when NIF returns - * or when independent environment is cleared. - */ +/* Temporary object header, auto-deallocated when NIF returns or when + * independent environment is cleared. + * + * The payload can be accessed with &tmp_obj_ptr[1] but keep in mind that its + * first element must not require greater alignment than `next`. */ struct enif_tmp_obj_t { struct enif_tmp_obj_t* next; void (*dtor)(struct enif_tmp_obj_t*); @@ -256,6 +258,46 @@ static ERTS_INLINE void free_tmp_objs(ErlNifEnv* env) } } +/* Whether the given environment is bound to a process and will be cleaned up + * when the NIF returns. It's safe to use temp_alloc for objects in + * env->tmp_obj_list when this is true. */ +static ERTS_INLINE int is_proc_bound(ErlNifEnv *env) +{ + return env->mod_nif != NULL; +} + +/* Allocates and attaches an object to the given environment, running its + * destructor when the environment is cleared. To avoid temporary variables the + * address of the allocated object is returned instead of the enif_tmp_obj_t. + * + * The destructor *must* call `erts_free(tmp_obj->allocator, tmp_obj)` to free + * the object. If the destructor needs to refer to the allocated object its + * address will be &tmp_obj[1]. */ +static ERTS_INLINE void *alloc_tmp_obj(ErlNifEnv *env, size_t size, + void (*dtor)(struct enif_tmp_obj_t*)) { + struct enif_tmp_obj_t *tmp_obj; + ErtsAlcType_t allocator; + + allocator = is_proc_bound(env) ? ERTS_ALC_T_TMP : ERTS_ALC_T_NIF; + + tmp_obj = erts_alloc(allocator, sizeof(struct enif_tmp_obj_t) + MAX(1, size)); + + tmp_obj->next = env->tmp_obj_list; + tmp_obj->allocator = allocator; + tmp_obj->dtor = dtor; + + env->tmp_obj_list = tmp_obj; + + return (void*)&tmp_obj[1]; +} + +/* Generic destructor for objects allocated through alloc_tmp_obj that don't + * care about their payload. */ +static void tmp_alloc_dtor(struct enif_tmp_obj_t *tmp_obj) +{ + erts_free(tmp_obj->allocator, tmp_obj); +} + void erts_post_nif(ErlNifEnv* env) { erts_unblock_fpe(env->fpe_was_unmasked); @@ -446,6 +488,7 @@ static void cache_env(ErlNifEnv* env) env->hp_end = env->heap_frag->mem + env->heap_frag->alloc_size; } } + void* enif_priv_data(ErlNifEnv* env) { return env->mod_nif->priv_data; @@ -1019,11 +1062,6 @@ int enif_is_number(ErlNifEnv* env, ERL_NIF_TERM term) return is_number(term); } -static ERTS_INLINE int is_proc_bound(ErlNifEnv* env) -{ - return env->mod_nif != NULL; -} - static void aligned_binary_dtor(struct enif_tmp_obj_t* obj) { erts_free_aligned_binary_bytes_extra((byte*)obj, obj->allocator); @@ -1058,22 +1096,14 @@ int enif_inspect_binary(ErlNifEnv* env, Eterm bin_term, ErlNifBinary* bin) u.tmp->dtor = &aligned_binary_dtor; env->tmp_obj_list = u.tmp; } - bin->bin_term = bin_term; bin->size = binary_size(bin_term); bin->ref_bin = NULL; ADD_READONLY_CHECK(env, bin->data, bin->size); return 1; } -static void tmp_alloc_dtor(struct enif_tmp_obj_t* obj) -{ - erts_free(obj->allocator, obj); -} - int enif_inspect_iolist_as_binary(ErlNifEnv* env, Eterm term, ErlNifBinary* bin) { - struct enif_tmp_obj_t* tobj; - ErtsAlcType_t allocator; ErlDrvSizeT sz; if (is_binary(term)) { return enif_inspect_binary(env,term,bin); @@ -1081,7 +1111,6 @@ int enif_inspect_iolist_as_binary(ErlNifEnv* env, Eterm term, ErlNifBinary* bin) if (is_nil(term)) { bin->data = (unsigned char*) &bin->data; /* dummy non-NULL */ bin->size = 0; - bin->bin_term = THE_NON_VALUE; bin->ref_bin = NULL; return 1; } @@ -1089,16 +1118,8 @@ int enif_inspect_iolist_as_binary(ErlNifEnv* env, Eterm term, ErlNifBinary* bin) return 0; } - allocator = is_proc_bound(env) ? ERTS_ALC_T_TMP : ERTS_ALC_T_NIF; - tobj = erts_alloc(allocator, sz + sizeof(struct enif_tmp_obj_t)); - tobj->allocator = allocator; - tobj->next = env->tmp_obj_list; - tobj->dtor = &tmp_alloc_dtor; - env->tmp_obj_list = tobj; - - bin->data = (unsigned char*) &tobj[1]; + bin->data = alloc_tmp_obj(env, sz, &tmp_alloc_dtor); bin->size = sz; - bin->bin_term = THE_NON_VALUE; bin->ref_bin = NULL; erts_iolist_to_buf(term, (char*) bin->data, sz); ADD_READONLY_CHECK(env, bin->data, bin->size); @@ -1116,7 +1137,6 @@ int enif_alloc_binary(size_t size, ErlNifBinary* bin) bin->size = size; bin->data = (unsigned char*) refbin->orig_bytes; - bin->bin_term = THE_NON_VALUE; bin->ref_bin = refbin; return 1; } @@ -1150,12 +1170,10 @@ void enif_release_binary(ErlNifBinary* bin) { if (bin->ref_bin != NULL) { Binary* refbin = bin->ref_bin; - ASSERT(bin->bin_term == THE_NON_VALUE); erts_bin_release(refbin); } #ifdef DEBUG bin->data = NULL; - bin->bin_term = THE_NON_VALUE; bin->ref_bin = NULL; #endif } @@ -1312,29 +1330,51 @@ int enif_get_string(ErlNifEnv *env, ERL_NIF_TERM list, char* buf, unsigned len, Eterm enif_make_binary(ErlNifEnv* env, ErlNifBinary* bin) { - if (bin->bin_term != THE_NON_VALUE) { - return bin->bin_term; - } - else if (bin->ref_bin != NULL) { - Binary* bptr = bin->ref_bin; - Eterm bin_term; - - bin_term = erts_build_proc_bin(&MSO(env->proc), - alloc_heap(env, PROC_BIN_SIZE), - bptr); - if (erts_refc_read(&bptr->intern.refc, 1) == 1) { - /* Total ownership transfer */ - bin->ref_bin = NULL; - bin->bin_term = bin_term; - } - return bin_term; - } - else { - flush_env(env); - bin->bin_term = new_binary(env->proc, bin->data, bin->size); - cache_env(env); - return bin->bin_term; + Eterm bin_term; + + if (bin->ref_bin != NULL) { + Binary* binary = bin->ref_bin; + + /* If the binary is smaller than the heap binary limit we'll return a + * heap binary to reduce the number of small refc binaries in the + * system. We can't simply release the refc binary right away however; + * the documentation states that the binary should be considered + * read-only from this point on, which implies that it should still be + * readable. + * + * We could keep it alive until we return by adding it to the temporary + * object list, but that requires an off-heap allocation which is + * potentially quite slow, so we create a dummy ProcBin instead and + * rely on the next minor GC to get rid of it. */ + if (bin->size <= ERL_ONHEAP_BIN_LIMIT) { + ErlHeapBin* hb; + + hb = (ErlHeapBin*)alloc_heap(env, heap_bin_size(bin->size)); + hb->thing_word = header_heap_bin(bin->size); + hb->size = bin->size; + + sys_memcpy(hb->data, bin->data, bin->size); + + erts_build_proc_bin(&MSO(env->proc), + alloc_heap(env, PROC_BIN_SIZE), + binary); + + bin_term = make_binary(hb); + } else { + bin_term = erts_build_proc_bin(&MSO(env->proc), + alloc_heap(env, PROC_BIN_SIZE), + binary); + } + + /* Our (possibly shared) ownership has been transferred to the term. */ + bin->ref_bin = NULL; + } else { + flush_env(env); + bin_term = new_binary(env->proc, bin->data, bin->size); + cache_env(env); } + + return bin_term; } Eterm enif_make_sub_binary(ErlNifEnv* env, ERL_NIF_TERM bin_term, @@ -3284,8 +3324,8 @@ typedef struct { Eterm sublist_start; Eterm sublist_end; - UWord offheap_size; - UWord onheap_size; + UWord referenced_size; + UWord copied_size; UWord iovec_len; } iovec_slice_t; @@ -3295,16 +3335,16 @@ static int examine_iovec_term(Eterm list, UWord max_length, iovec_slice_t *resul result->sublist_start = list; result->sublist_length = 0; - result->offheap_size = 0; - result->onheap_size = 0; + result->referenced_size = 0; + result->copied_size = 0; result->iovec_len = 0; lookahead = result->sublist_start; while (is_list(lookahead)) { - Eterm *binary_header, binary; + UWord byte_size; + Eterm binary; Eterm *cell; - UWord size; cell = list_val(lookahead); binary = CAR(cell); @@ -3313,35 +3353,36 @@ static int examine_iovec_term(Eterm list, UWord max_length, iovec_slice_t *resul return 0; } - size = binary_size(binary); - binary_header = binary_val(binary); + byte_size = binary_size(binary); + + if (byte_size > 0) { + int bit_offset, bit_size; + Eterm parent_binary; + UWord byte_offset; - if (size > 0) { - /* If we're a sub-binary we'll need to check our underlying binary - * to determine whether we're on-heap or not. */ - if (thing_subtag(*binary_header) == SUB_BINARY_SUBTAG) { - ErlSubBin *sb = (ErlSubBin*)binary_header; + int requires_copying; - /* Reject bitstrings */ - if((sb->bitoffs + sb->bitsize) > 0) { - return 0; - } + ERTS_GET_REAL_BIN(binary, parent_binary, byte_offset, + bit_offset, bit_size); - ASSERT(size <= binary_size(sb->orig)); - binary_header = binary_val(sb->orig); + (void)byte_offset; + + if (bit_size != 0) { + return 0; } - if (thing_subtag(*binary_header) == HEAP_BINARY_SUBTAG) { - ASSERT(size <= ERL_ONHEAP_BIN_LIMIT); + /* If we're unaligned or an on-heap binary we'll need to copy + * ourselves over to a temporary buffer. */ + requires_copying = (bit_offset != 0) || + thing_subtag(*binary_val(parent_binary)) == HEAP_BINARY_SUBTAG; - result->iovec_len += 1; - result->onheap_size += size; + if (requires_copying) { + result->copied_size += byte_size; } else { - ASSERT(thing_subtag(*binary_header) == REFC_BINARY_SUBTAG); - - result->iovec_len += 1 + size / MAX_SYSIOVEC_IOVLEN; - result->offheap_size += size; + result->referenced_size += byte_size; } + + result->iovec_len += 1 + byte_size / MAX_SYSIOVEC_IOVLEN; } result->sublist_length += 1; @@ -3361,7 +3402,9 @@ static int examine_iovec_term(Eterm list, UWord max_length, iovec_slice_t *resul return 1; } -static void inspect_raw_binary_data(Eterm binary, ErlNifBinary *result) { +static void marshal_iovec_binary(Eterm binary, ErlNifBinary *copy_buffer, + UWord *copy_offset, ErlNifBinary *result) { + Eterm *parent_header; Eterm parent_binary; @@ -3372,10 +3415,11 @@ static void inspect_raw_binary_data(Eterm binary, ErlNifBinary *result) { ERTS_GET_REAL_BIN(binary, parent_binary, byte_offset, bit_offset, bit_size); + ASSERT(bit_size == 0); + parent_header = binary_val(parent_binary); result->size = binary_size(binary); - result->bin_term = binary; if (thing_subtag(*parent_header) == REFC_BINARY_SUBTAG) { ProcBin *pb = (ProcBin*)parent_header; @@ -3398,24 +3442,48 @@ static void inspect_raw_binary_data(Eterm binary, ErlNifBinary *result) { result->data = &((unsigned char*)&hb->data)[byte_offset]; result->ref_bin = NULL; } + + /* If this isn't an *aligned* refc binary, copy its contents to the buffer + * and reference that instead. */ + + if (result->ref_bin == NULL || bit_offset != 0) { + ASSERT(copy_buffer->ref_bin != NULL && copy_buffer->data != NULL); + ASSERT(result->size <= (copy_buffer->size - *copy_offset)); + + if (bit_offset == 0) { + sys_memcpy(©_buffer->data[*copy_offset], + result->data, result->size); + } else { + erts_copy_bits(result->data, bit_offset, 1, + (byte*)©_buffer->data[*copy_offset], 0, 1, + result->size * 8); + } + + result->data = ©_buffer->data[*copy_offset]; + result->ref_bin = copy_buffer->ref_bin; + + *copy_offset += result->size; + } } static int fill_iovec_with_slice(ErlNifEnv *env, iovec_slice_t *slice, ErlNifIOVec *iovec) { - UWord onheap_offset, iovec_idx; - ErlNifBinary onheap_data; + ErlNifBinary copy_buffer = {0}; + UWord copy_offset, iovec_idx; Eterm sublist_iterator; - /* Set up a common refc binary for all on-heap binaries. */ - if (slice->onheap_size > 0) { - if (!enif_alloc_binary(slice->onheap_size, &onheap_data)) { + /* Set up a common refc binary for all on-heap and unaligned binaries. */ + if (slice->copied_size > 0) { + if (!enif_alloc_binary(slice->copied_size, ©_buffer)) { return 0; } + + ASSERT(copy_buffer.ref_bin != NULL); } sublist_iterator = slice->sublist_start; - onheap_offset = 0; + copy_offset = 0; iovec_idx = 0; while (sublist_iterator != slice->sublist_end) { @@ -3423,20 +3491,7 @@ static int fill_iovec_with_slice(ErlNifEnv *env, Eterm *cell; cell = list_val(sublist_iterator); - inspect_raw_binary_data(CAR(cell), &raw_data); - - /* If this isn't a refc binary, copy its contents to the onheap buffer - * and reference that instead. */ - if (raw_data.size > 0 && raw_data.ref_bin == NULL) { - ASSERT(onheap_offset < onheap_data.size); - ASSERT(slice->onheap_size > 0); - - sys_memcpy(&onheap_data.data[onheap_offset], - raw_data.data, raw_data.size); - - raw_data.data = &onheap_data.data[onheap_offset]; - raw_data.ref_bin = onheap_data.ref_bin; - } + marshal_iovec_binary(CAR(cell), ©_buffer, ©_offset, &raw_data); while (raw_data.size > 0) { UWord chunk_len = MIN(raw_data.size, MAX_SYSIOVEC_IOVLEN); @@ -3467,16 +3522,18 @@ static int fill_iovec_with_slice(ErlNifEnv *env, erts_refc_inc(&refc_binary->intern.refc, 1); } - if (slice->onheap_size > 0) { + if (slice->copied_size > 0) { /* Transfer ownership to the iovec; we've taken references to it in * the above loop. */ - enif_release_binary(&onheap_data); + enif_release_binary(©_buffer); } } else { - if (slice->onheap_size > 0) { - /* Attach the binary to our environment and let the GC take care of - * it after returning. */ - enif_make_binary(env, &onheap_data); + if (slice->copied_size > 0) { + /* Attach the binary to our environment and let the next minor GC + * get rid of it. This is slightly faster than using the tmp object + * list since it avoids off-heap allocations. */ + erts_build_proc_bin(&MSO(env->proc), + alloc_heap(env, PROC_BIN_SIZE), copy_buffer.ref_bin); } } @@ -3502,19 +3559,14 @@ static int create_iovec_from_slice(ErlNifEnv *env, alloc_size = binv_offset; alloc_size += slice->iovec_len * sizeof(Binary*); - /* If we have an environment we'll attach the allocated data to it. The - * GC will take care of releasing it later on. */ + /* When the user passes an environment, we attach the iovec to it so + * the user won't have to bother managing it (similar to + * enif_inspect_binary). It'll disappear once the environment is + * cleaned up. */ if (env != NULL) { - ErlNifBinary gc_bin; - - if (!enif_alloc_binary(alloc_size, &gc_bin)) { - return 0; - } - - alloc_base = (char*)gc_bin.data; - enif_make_binary(env, &gc_bin); + alloc_base = alloc_tmp_obj(env, alloc_size, &tmp_alloc_dtor); } else { - alloc_base = enif_alloc(alloc_size); + alloc_base = erts_alloc(ERTS_ALC_T_NIF, alloc_size); } iovec = (ErlNifIOVec*)alloc_base; @@ -3523,12 +3575,12 @@ static int create_iovec_from_slice(ErlNifEnv *env, iovec->flags = 0; } - iovec->size = slice->offheap_size + slice->onheap_size; + iovec->size = slice->referenced_size + slice->copied_size; iovec->iovcnt = slice->iovec_len; if(!fill_iovec_with_slice(env, slice, iovec)) { if (env == NULL && !(iovec->flags & ERL_NIF_IOVEC_FLAGS_PREALLOC)) { - enif_free(iovec); + erts_free(ERTS_ALC_T_NIF, iovec); } return 0; @@ -4218,34 +4270,31 @@ static unsigned calc_checksum(unsigned char* ptr, unsigned size); struct readonly_check_t { - struct enif_tmp_obj_t hdr; unsigned char* ptr; unsigned size; unsigned checksum; }; static void add_readonly_check(ErlNifEnv* env, unsigned char* ptr, unsigned sz) { - ErtsAlcType_t allocator = is_proc_bound(env) ? ERTS_ALC_T_TMP : ERTS_ALC_T_NIF; - struct readonly_check_t* obj = erts_alloc(allocator, - sizeof(struct readonly_check_t)); - obj->hdr.allocator = allocator; - obj->hdr.next = env->tmp_obj_list; - env->tmp_obj_list = &obj->hdr; - obj->hdr.dtor = &readonly_check_dtor; + struct readonly_check_t* obj; + + obj = alloc_tmp_obj(env, sizeof(struct readonly_check_t), + &readonly_check_dtor); + obj->ptr = ptr; obj->size = sz; - obj->checksum = calc_checksum(ptr, sz); + obj->checksum = calc_checksum(ptr, sz); } -static void readonly_check_dtor(struct enif_tmp_obj_t* o) +static void readonly_check_dtor(struct enif_tmp_obj_t* tmp_obj) { - struct readonly_check_t* obj = (struct readonly_check_t*) o; - unsigned chksum = calc_checksum(obj->ptr, obj->size); - if (chksum != obj->checksum) { + struct readonly_check_t* ro_check = (struct readonly_check_t*)&tmp_obj[1]; + unsigned chksum = calc_checksum(ro_check->ptr, ro_check->size); + if (chksum != ro_check->checksum) { fprintf(stderr, "\r\nReadonly data written by NIF, checksums differ" - " %x != %x\r\nABORTING\r\n", chksum, obj->checksum); + " %x != %x\r\nABORTING\r\n", chksum, ro_check->checksum); abort(); } - erts_free(obj->hdr.allocator, obj); + erts_free(tmp_obj->allocator, tmp_obj); } static unsigned calc_checksum(unsigned char* ptr, unsigned size) { |