wingo pushed a commit to branch wip-whippet
in repository guile.
commit 1e41f0e093da51cd93c1b5c2d8ce78305f34b18a
Author: Andy Wingo <wi...@igalia.com>
AuthorDate: Wed Apr 23 11:31:15 2025 +0200
mmc: Tail-call an out-of-memory handler if allocation fails
---
src/mmc.c | 79 +++++++++++++++++++++++++++++++++-----------------------
src/nofl-space.h | 5 ++--
2 files changed, 48 insertions(+), 36 deletions(-)
diff --git a/src/mmc.c b/src/mmc.c
index d2bc4df9d..05b2334cc 100644
--- a/src/mmc.c
+++ b/src/mmc.c
@@ -66,6 +66,7 @@ struct gc_heap {
struct gc_heap_sizer sizer;
struct gc_event_listener event_listener;
void *event_listener_data;
+ void* (*allocation_failure)(struct gc_heap*, size_t);
};
#define HEAP_EVENT(heap, event, ...) do { \
@@ -511,20 +512,18 @@ heap_estimate_live_data_after_gc(struct gc_heap *heap,
return bytes;
}
-static void
-detect_out_of_memory(struct gc_heap *heap, uintptr_t allocation_since_last_gc)
{
- if (heap->sizer.policy != GC_HEAP_SIZE_FIXED)
- return;
-
- if (allocation_since_last_gc >
nofl_space_fragmentation(heap_nofl_space(heap)))
- return;
-
- if (heap->gc_kind == GC_COLLECTION_MINOR)
- return;
+static int
+compute_progress(struct gc_heap *heap, uintptr_t allocation_since_last_gc) {
+ struct nofl_space *nofl = heap_nofl_space(heap);
+ return allocation_since_last_gc > nofl_space_fragmentation(nofl);
+}
- // No allocation since last gc: out of memory.
- fprintf(stderr, "ran out of space, heap size %zu\n", heap->size);
- GC_CRASH();
+static int
+compute_success(struct gc_heap *heap, enum gc_collection_kind gc_kind,
+ int progress) {
+ return progress
+ || gc_kind == GC_COLLECTION_MINOR
+ || heap->sizer.policy != GC_HEAP_SIZE_FIXED;
}
static double
@@ -750,12 +749,10 @@ sweep_ephemerons(struct gc_heap *heap) {
return gc_sweep_pending_ephemerons(heap->pending_ephemerons, 0, 1);
}
-static void collect(struct gc_mutator *mut,
- enum gc_collection_kind requested_kind,
- int requested_by_user) GC_NEVER_INLINE;
-static void
-collect(struct gc_mutator *mut, enum gc_collection_kind requested_kind,
- int requested_by_user) {
+static int collect(struct gc_mutator *mut,
+ enum gc_collection_kind requested_kind) GC_NEVER_INLINE;
+static int
+collect(struct gc_mutator *mut, enum gc_collection_kind requested_kind) {
struct gc_heap *heap = mutator_heap(mut);
struct nofl_space *nofl_space = heap_nofl_space(heap);
struct large_object_space *lospace = heap_large_object_space(heap);
@@ -773,8 +770,7 @@ collect(struct gc_mutator *mut, enum gc_collection_kind
requested_kind,
nofl_space_add_to_allocation_counter(nofl_space, &allocation_counter);
large_object_space_add_to_allocation_counter(lospace, &allocation_counter);
heap->total_allocated_bytes_at_last_gc += allocation_counter;
- if (!requested_by_user)
- detect_out_of_memory(heap, allocation_counter);
+ int progress = compute_progress(heap, allocation_counter);
enum gc_collection_kind gc_kind =
determine_collection_kind(heap, requested_kind);
int is_minor = gc_kind == GC_COLLECTION_MINOR;
@@ -821,12 +817,12 @@ collect(struct gc_mutator *mut, enum gc_collection_kind
requested_kind,
heap->size_at_last_gc = heap->size;
HEAP_EVENT(heap, restarting_mutators);
allow_mutators_to_continue(heap);
+ return compute_success(heap, gc_kind, progress);
}
-static void
+static int
trigger_collection(struct gc_mutator *mut,
- enum gc_collection_kind requested_kind,
- int requested_by_user) {
+ enum gc_collection_kind requested_kind) {
struct gc_heap *heap = mutator_heap(mut);
int prev_kind = -1;
gc_stack_capture_hot(&mut->stack);
@@ -836,14 +832,16 @@ trigger_collection(struct gc_mutator *mut,
heap_lock(heap);
while (mutators_are_stopping(heap))
prev_kind = pause_mutator_for_collection(heap, mut);
+ int success = 1;
if (prev_kind < (int)requested_kind)
- collect(mut, requested_kind, requested_by_user);
+ success = collect(mut, requested_kind);
heap_unlock(heap);
+ return success;
}
void
gc_collect(struct gc_mutator *mut, enum gc_collection_kind kind) {
- trigger_collection(mut, kind, 1);
+ trigger_collection(mut, kind);
}
int*
@@ -903,8 +901,10 @@ allocate_large(struct gc_mutator *mut, size_t size,
nofl_space_request_release_memory(nofl_space,
npages << lospace->page_size_log2);
- while (!nofl_space_shrink(nofl_space, 0))
- trigger_collection(mut, GC_COLLECTION_COMPACTING, 0);
+ while (!nofl_space_shrink(nofl_space, 0)) {
+ if (!trigger_collection(mut, GC_COLLECTION_COMPACTING))
+ return heap->allocation_failure(heap, size);
+ }
atomic_fetch_add(&heap->large_object_pages, npages);
void *ret = large_object_space_alloc(lospace, npages, kind);
@@ -919,7 +919,7 @@ allocate_large(struct gc_mutator *mut, size_t size,
static void
collect_for_small_allocation(void *mut) {
- trigger_collection(mut, GC_COLLECTION_ANY, 0);
+ trigger_collection(mut, GC_COLLECTION_ANY);
}
void*
@@ -930,10 +930,16 @@ gc_allocate_slow(struct gc_mutator *mut, size_t size,
if (size > gc_allocator_large_threshold())
return allocate_large(mut, size, compute_trace_kind(kind));
- return gc_ref_heap_object(nofl_allocate(&mut->allocator,
- heap_nofl_space(mutator_heap(mut)),
- size, collect_for_small_allocation,
- mut, kind));
+ struct gc_heap *heap = mutator_heap(mut);
+ while (1) {
+ struct gc_ref ret = nofl_allocate(&mut->allocator, heap_nofl_space(heap),
+ size, kind);
+ if (!gc_ref_is_null(ret))
+ return gc_ref_heap_object(ret);
+ if (trigger_collection(mut, GC_COLLECTION_ANY))
+ continue;
+ return heap->allocation_failure(heap, size);
+ }
}
void
@@ -1109,6 +1115,12 @@ static void set_heap_size_from_thread(struct gc_heap
*heap, size_t size) {
pthread_mutex_unlock(&heap->lock);
}
+static void* allocation_failure(struct gc_heap *heap, size_t size) {
+ fprintf(stderr, "ran out of space, heap size %zu\n", heap->size);
+ GC_CRASH();
+ return NULL;
+}
+
static int
heap_init(struct gc_heap *heap, const struct gc_options *options) {
// *heap is already initialized to 0.
@@ -1143,6 +1155,7 @@ heap_init(struct gc_heap *heap, const struct gc_options
*options) {
allocation_counter_from_thread,
set_heap_size_from_thread,
heap->background_thread);
+ heap->allocation_failure = allocation_failure;
return 1;
}
diff --git a/src/nofl-space.h b/src/nofl-space.h
index 2668232c6..56e226bd4 100644
--- a/src/nofl-space.h
+++ b/src/nofl-space.h
@@ -880,8 +880,7 @@ nofl_allocator_next_hole(struct nofl_allocator *alloc,
static struct gc_ref
nofl_allocate(struct nofl_allocator *alloc, struct nofl_space *space,
- size_t size, void (*gc)(void*), void *gc_data,
- enum gc_allocation_kind kind) {
+ size_t size, enum gc_allocation_kind kind) {
GC_ASSERT(size > 0);
GC_ASSERT(size <= gc_allocator_large_threshold());
size = align_up(size, NOFL_GRANULE_SIZE);
@@ -894,7 +893,7 @@ nofl_allocate(struct nofl_allocator *alloc, struct
nofl_space *space,
break;
}
if (!hole)
- gc(gc_data);
+ return gc_ref_null();
}
}
