wingo pushed a commit to branch wip-whippet
in repository guile.
commit e40b224fafa6dd99c65552024249ea1410b783de
Author: Andy Wingo <wi...@igalia.com>
AuthorDate: Mon Aug 5 15:03:24 2024 +0200
Attempt to dynamically choose whether to atomically forward
---
src/copy-space.h | 34 ++++++++++++++++++++++++++++------
src/pcc.c | 3 ++-
src/scc.c | 3 ++-
3 files changed, 32 insertions(+), 8 deletions(-)
diff --git a/src/copy-space.h b/src/copy-space.h
index 2d6b2f246..a863ca51a 100644
--- a/src/copy-space.h
+++ b/src/copy-space.h
@@ -116,6 +116,7 @@ struct copy_space {
// The rest of these members are only changed rarely and with the heap
// lock.
uint8_t active_region ALIGNED_TO_AVOID_FALSE_SHARING;
+ uint8_t atomic_forward;
size_t allocated_bytes_at_last_gc;
size_t fragmentation_at_last_gc;
struct copy_space_extent *extents;
@@ -411,8 +412,9 @@ copy_space_gc_during_evacuation(void *data) {
}
static inline int
-copy_space_forward(struct copy_space *space, struct gc_edge edge,
- struct gc_ref old_ref, struct copy_space_allocator *alloc) {
+copy_space_forward_atomic(struct copy_space *space, struct gc_edge edge,
+ struct gc_ref old_ref,
+ struct copy_space_allocator *alloc) {
GC_ASSERT(copy_space_object_region(old_ref) != space->active_region);
struct gc_atomic_forward fwd = gc_atomic_forward_begin(old_ref);
@@ -459,8 +461,9 @@ copy_space_forward(struct copy_space *space, struct gc_edge
edge,
}
static int
-copy_space_forward_if_traced(struct copy_space *space, struct gc_edge edge,
- struct gc_ref old_ref) {
+copy_space_forward_if_traced_atomic(struct copy_space *space,
+ struct gc_edge edge,
+ struct gc_ref old_ref) {
GC_ASSERT(copy_space_object_region(old_ref) != space->active_region);
struct gc_atomic_forward fwd = gc_atomic_forward_begin(old_ref);
switch (fwd.state) {
@@ -486,7 +489,8 @@ copy_space_forward_if_traced(struct copy_space *space,
struct gc_edge edge,
static inline int
copy_space_forward_nonatomic(struct copy_space *space, struct gc_edge edge,
- struct gc_ref old_ref, struct
copy_space_allocator *alloc) {
+ struct gc_ref old_ref,
+ struct copy_space_allocator *alloc) {
GC_ASSERT(copy_space_object_region(old_ref) != space->active_region);
uintptr_t forwarded = gc_object_forwarded_nonatomic(old_ref);
@@ -519,6 +523,23 @@ copy_space_forward_if_traced_nonatomic(struct copy_space
*space,
return 0;
}
+static inline int
+copy_space_forward(struct copy_space *space, struct gc_edge edge,
+ struct gc_ref old_ref,
+ struct copy_space_allocator *alloc) {
+ if (space->atomic_forward)
+ return copy_space_forward_atomic(space, edge, old_ref, alloc);
+ return copy_space_forward_nonatomic(space, edge, old_ref, alloc);
+}
+
+static inline int
+copy_space_forward_if_traced(struct copy_space *space, struct gc_edge edge,
+ struct gc_ref old_ref) {
+ if (space->atomic_forward)
+ return copy_space_forward_if_traced_atomic(space, edge, old_ref);
+ return copy_space_forward_if_traced_nonatomic(space, edge, old_ref);
+}
+
static inline int
copy_space_contains(struct copy_space *space, struct gc_ref ref) {
for (size_t i = 0; i < space->nextents; i++)
@@ -567,7 +588,7 @@ copy_space_allocate_slabs(size_t nslabs) {
}
static int
-copy_space_init(struct copy_space *space, size_t size) {
+copy_space_init(struct copy_space *space, size_t size, int atomic) {
size = align_up(size, COPY_SPACE_BLOCK_SIZE);
size_t reserved = align_up(size, COPY_SPACE_SLAB_SIZE);
size_t nslabs = reserved / COPY_SPACE_SLAB_SIZE;
@@ -583,6 +604,7 @@ copy_space_init(struct copy_space *space, size_t size) {
space->fragmentation = 0;
space->bytes_to_page_out = 0;
space->active_region = 0;
+ space->atomic_forward = atomic;
space->allocated_bytes_at_last_gc = 0;
space->fragmentation_at_last_gc = 0;
space->extents = calloc(1, sizeof(struct copy_space_extent));
diff --git a/src/pcc.c b/src/pcc.c
index b0aeddda0..3023d465d 100644
--- a/src/pcc.c
+++ b/src/pcc.c
@@ -611,7 +611,8 @@ int gc_init(const struct gc_options *options, struct
gc_stack_addr *stack_base,
HEAP_EVENT(*heap, init, (*heap)->size);
struct copy_space *space = heap_copy_space(*heap);
- if (!copy_space_init(space, (*heap)->size)) {
+ int atomic_forward = options->common.parallelism > 1;
+ if (!copy_space_init(space, (*heap)->size, atomic_forward)) {
free(*heap);
*heap = NULL;
return 0;
diff --git a/src/scc.c b/src/scc.c
index 28dcef0d2..33fe8a1b1 100644
--- a/src/scc.c
+++ b/src/scc.c
@@ -611,7 +611,8 @@ int gc_init(const struct gc_options *options, struct
gc_stack_addr *stack_base,
HEAP_EVENT(*heap, init, (*heap)->size);
struct copy_space *space = heap_copy_space(*heap);
- if (!copy_space_init(space, (*heap)->size)) {
+ int atomic_forward = 0;
+ if (!copy_space_init(space, (*heap)->size, atomic_forward)) {
free(*heap);
*heap = NULL;
return 0;
