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authorJean Boussier <jean.boussier@gmail.com>2023-03-06 13:50:33 +0100
committerJean Boussier <jean.boussier@gmail.com>2023-03-06 14:44:15 +0100
commit3c1bd7982b93803ab7d37c3bd14730926f228d46 (patch)
treea1a7dd2f749f8a206c811762fe8e3ca492aea913 /ext
parent99046c1852786fc3b23f3a5381b50bfe6caee798 (diff)
downloadffi-3c1bd7982b93803ab7d37c3bd14730926f228d46.tar.gz
Implement Write Barrier and dsize for FFI::Type
Ref: https://github.com/ffi/ffi/pull/991 Write barrier protected objects are allowed to be promoted to the old generation, which means they only get marked on major GC. The downside is that the RB_BJ_WRITE macro MUST be used to set references, otherwise the referenced object may be garbaged collected. This commit also implement a `dsize` function so that these instance report a more relevant size in various memory profilers. While I was at it I removed the `strdup` of `BuiltinType.name`, I don't see why we wouldn't directly point at static memory, that saves copying type names, and makes freeing builtin types easier.
Diffstat (limited to 'ext')
-rw-r--r--ext/ffi_c/MappedType.c21
-rw-r--r--ext/ffi_c/MappedType.h1
-rw-r--r--ext/ffi_c/Type.c39
-rw-r--r--ext/ffi_c/Type.h2
4 files changed, 40 insertions, 23 deletions
diff --git a/ext/ffi_c/MappedType.c b/ext/ffi_c/MappedType.c
index 304de86..ed05c9d 100644
--- a/ext/ffi_c/MappedType.c
+++ b/ext/ffi_c/MappedType.c
@@ -39,6 +39,7 @@
static VALUE mapped_allocate(VALUE);
static VALUE mapped_initialize(VALUE, VALUE);
static void mapped_mark(void *);
+static size_t mapped_memsize(const void *);
static ID id_native_type, id_to_native, id_from_native;
VALUE rbffi_MappedTypeClass = Qnil;
@@ -48,10 +49,12 @@ static const rb_data_type_t mapped_type_data_type = {
.function = {
.dmark = mapped_mark,
.dfree = RUBY_TYPED_DEFAULT_FREE,
- .dsize = NULL,
+ .dsize = mapped_memsize,
},
.parent = &rbffi_type_data_type,
- .flags = RUBY_TYPED_FREE_IMMEDIATELY
+ // IMPORTANT: WB_PROTECTED objects must only use the RB_OBJ_WRITE()
+ // macro to update VALUE references, as to trigger write barriers.
+ .flags = RUBY_TYPED_FREE_IMMEDIATELY | RUBY_TYPED_WB_PROTECTED
};
@@ -62,8 +65,8 @@ mapped_allocate(VALUE klass)
VALUE obj = TypedData_Make_Struct(klass, MappedType, &mapped_type_data_type, m);
- m->rbConverter = Qnil;
- m->rbType = Qnil;
+ RB_OBJ_WRITE(obj, &m->rbConverter, Qnil);
+ RB_OBJ_WRITE(obj, &m->rbType, Qnil);
m->type = NULL;
m->base.nativeType = NATIVE_MAPPED;
m->base.ffiType = &ffi_type_void;
@@ -95,12 +98,12 @@ mapped_initialize(VALUE self, VALUE rbConverter)
}
TypedData_Get_Struct(self, MappedType, &mapped_type_data_type, m);
- m->rbType = rb_funcall2(rbConverter, id_native_type, 0, NULL);
+ RB_OBJ_WRITE(self, &m->rbType, rb_funcall2(rbConverter, id_native_type, 0, NULL));
if (!(rb_obj_is_kind_of(m->rbType, rbffi_TypeClass))) {
rb_raise(rb_eTypeError, "native_type did not return instance of FFI::Type");
}
- m->rbConverter = rbConverter;
+ RB_OBJ_WRITE(self, &m->rbConverter, rbConverter);
TypedData_Get_Struct(m->rbType, Type, &rbffi_type_data_type, m->type);
m->base.ffiType = m->type->ffiType;
@@ -115,6 +118,12 @@ mapped_mark(void* data)
rb_gc_mark(m->rbConverter);
}
+static size_t
+mapped_memsize(const void *data)
+{
+ return sizeof(MappedType);
+}
+
/*
* call-seq: mapped_type.native_type
* @return [Type]
diff --git a/ext/ffi_c/MappedType.h b/ext/ffi_c/MappedType.h
index ac86a3c..9f6f9ee 100644
--- a/ext/ffi_c/MappedType.h
+++ b/ext/ffi_c/MappedType.h
@@ -43,7 +43,6 @@ typedef struct MappedType_ {
Type* type;
VALUE rbConverter;
VALUE rbType;
-
} MappedType;
void rbffi_MappedType_Init(VALUE moduleFFI);
diff --git a/ext/ffi_c/Type.c b/ext/ffi_c/Type.c
index d940e94..6089a14 100644
--- a/ext/ffi_c/Type.c
+++ b/ext/ffi_c/Type.c
@@ -39,13 +39,14 @@
#include "Types.h"
#include "Type.h"
+static size_t type_memsize(const void *);
typedef struct BuiltinType_ {
Type type;
- char* name;
+ const char* name;
} BuiltinType;
-static void builtin_type_free(void *);
+static size_t builtin_type_memsize(const void *);
VALUE rbffi_TypeClass = Qnil;
@@ -59,22 +60,32 @@ const rb_data_type_t rbffi_type_data_type = { /* extern */
.function = {
.dmark = NULL,
.dfree = RUBY_TYPED_DEFAULT_FREE,
- .dsize = NULL,
+ .dsize = type_memsize,
},
- .flags = RUBY_TYPED_FREE_IMMEDIATELY
+ // IMPORTANT: WB_PROTECTED objects must only use the RB_OBJ_WRITE()
+ // macro to update VALUE references, as to trigger write barriers.
+ .flags = RUBY_TYPED_FREE_IMMEDIATELY | RUBY_TYPED_WB_PROTECTED
};
static const rb_data_type_t builtin_type_data_type = {
.wrap_struct_name = "FFI::Type::Builtin",
.function = {
.dmark = NULL,
- .dfree = builtin_type_free,
- .dsize = NULL,
+ .dfree = RUBY_TYPED_DEFAULT_FREE,
+ .dsize = builtin_type_memsize,
},
.parent = &rbffi_type_data_type,
- .flags = RUBY_TYPED_FREE_IMMEDIATELY
+ // IMPORTANT: WB_PROTECTED objects must only use the RB_OBJ_WRITE()
+ // macro to update VALUE references, as to trigger write barriers.
+ .flags = RUBY_TYPED_FREE_IMMEDIATELY | RUBY_TYPED_WB_PROTECTED
};
+static size_t
+type_memsize(const void *data)
+{
+ return sizeof(Type);
+}
+
static VALUE
type_allocate(VALUE klass)
{
@@ -83,7 +94,7 @@ type_allocate(VALUE klass)
type->nativeType = -1;
type->ffiType = &ffi_type_void;
-
+
return obj;
}
@@ -170,20 +181,18 @@ builtin_type_new(VALUE klass, int nativeType, ffi_type* ffiType, const char* nam
VALUE obj = Qnil;
obj = TypedData_Make_Struct(klass, BuiltinType, &builtin_type_data_type, type);
-
- type->name = strdup(name);
+
+ type->name = name;
type->type.nativeType = nativeType;
type->type.ffiType = ffiType;
return obj;
}
-static void
-builtin_type_free(void *data)
+static size_t
+builtin_type_memsize(const void *data)
{
- BuiltinType *type = (BuiltinType *)data;
- free(type->name);
- xfree(type);
+ return sizeof(BuiltinType) + sizeof(ffi_type);
}
/*
diff --git a/ext/ffi_c/Type.h b/ext/ffi_c/Type.h
index 74a931b..b6de634 100644
--- a/ext/ffi_c/Type.h
+++ b/ext/ffi_c/Type.h
@@ -44,7 +44,7 @@ extern "C" {
typedef struct Type_ Type;
#include "Types.h"
-
+
struct Type_ {
NativeType nativeType;
ffi_type* ffiType;