Author: Remi Meier <remi.me...@inf.ethz.ch>
Branch: card-marking
Changeset: r1242:008b3c48e38b
Date: 2014-05-23 09:55 +0200
http://bitbucket.org/pypy/stmgc/changeset/008b3c48e38b/
Log: some clarifications and adding the second fastpath to
stm_write_card()
diff --git a/c7/stm/core.c b/c7/stm/core.c
--- a/c7/stm/core.c
+++ b/c7/stm/core.c
@@ -40,7 +40,7 @@
#endif
}
-static void _stm_mark_card(object_t *obj, uintptr_t card_index)
+void _stm_mark_card(object_t *obj, uintptr_t card_index)
{
assert(card_index > 0);
@@ -115,12 +115,27 @@
assert(_seems_to_be_running_transaction());
assert(!_is_young(obj));
assert(obj->stm_flags & GCFLAG_WRITE_BARRIER);
+ assert(IMPLY(card_index, (card_index - 1) * CARD_SIZE <
stmcb_size_rounded_up(
+ (struct object_s*)REAL_ADDRESS(STM_SEGMENT->segment_base,
obj))));
+
+ uintptr_t base_lock_idx = get_write_lock_idx((uintptr_t)obj);
+ uint8_t lock_num = STM_PSEGMENT->write_lock_num;
+ assert(base_lock_idx < sizeof(write_locks));
if (!(obj->stm_flags & GCFLAG_HAS_CARDS))
card_index = 0; /* assume no cards */
- assert(IMPLY(card_index, (card_index - 1) * CARD_SIZE <
stmcb_size_rounded_up(
- (struct object_s*)REAL_ADDRESS(STM_SEGMENT->segment_base,
obj))));
+ /* if card_index and obj->stm_flags & CARDS_SET:
+ directly mark the card of obj at card_index
+ return (no STM part needed)
+ -> see stmgc.h */
+ /* if CARDS_SET, we entered here at least once, so we own the write_lock
+ OR this is an overflow object and the write_lock is not owned */
+ OPT_ASSERT(
+ IMPLY(obj->stm_flags & GCFLAG_CARDS_SET,
+ (!IS_OVERFLOW_OBJ(STM_PSEGMENT, obj) &&
write_locks[base_lock_idx] == lock_num)
+ || (IS_OVERFLOW_OBJ(STM_PSEGMENT, obj) &&
write_locks[base_lock_idx] == 0)
+ ));
if (_stm_write_slowpath_overflow_objs(obj, card_index))
return;
@@ -136,9 +151,7 @@
'modified_old_objects' (but, because it had GCFLAG_WRITE_BARRIER,
not in 'objects_pointing_to_nursery'). We'll detect this case
by finding that we already own the write-lock. */
- uintptr_t base_lock_idx = get_write_lock_idx((uintptr_t)obj);
- uint8_t lock_num = STM_PSEGMENT->write_lock_num;
- assert(base_lock_idx < sizeof(write_locks));
+
retry:
if (write_locks[base_lock_idx] == 0) {
/* A lock to prevent reading garbage from
diff --git a/c7/stm/core.h b/c7/stm/core.h
--- a/c7/stm/core.h
+++ b/c7/stm/core.h
@@ -233,8 +233,8 @@
#define REAL_ADDRESS(segment_base, src) ((segment_base) + (uintptr_t)(src))
-#define IS_OVERFLOW_OBJ(pseg, obj) ((obj->stm_flags &
-GCFLAG_OVERFLOW_NUMBER_bit0) \
- == pseg->overflow_number)
+#define IS_OVERFLOW_OBJ(pseg, obj) (((obj)->stm_flags &
-GCFLAG_OVERFLOW_NUMBER_bit0) \
+ == (pseg)->overflow_number)
static inline uintptr_t get_card_index(uintptr_t byte_offset) {
return (byte_offset / CARD_SIZE) + 1;
diff --git a/c7/stmgc.h b/c7/stmgc.h
--- a/c7/stmgc.h
+++ b/c7/stmgc.h
@@ -108,6 +108,7 @@
but it's not exposed to C code so far */
void _stm_write_slowpath(object_t *);
void _stm_write_slowpath_card(object_t *, uintptr_t);
+void _stm_mark_card(object_t *obj, uintptr_t card_index);
object_t *_stm_allocate_slowpath(ssize_t);
object_t *_stm_allocate_external(ssize_t);
void _stm_become_inevitable(const char*);
@@ -221,16 +222,23 @@
}
/* The following is a GC-optimized barrier that works on the granularity
- of CARD_SIZE. It can only be used on objects one called stm_use_cards()
- on. It has the same purpose as stm_write() for TM.
+ of CARD_SIZE. It can only be used on objects one any object, but only
+ helps with those that were internally marked with GCFLAG_HAS_CARDS
+ It has the same purpose as stm_write() for TM.
'index' is the byte-offset into the object divided by _STM_CARD_SIZE
plus 1: (offset // CARD_SIZE) + 1
*/
__attribute__((always_inline))
static inline void stm_write_card(object_t *obj, uintptr_t index)
{
- if (UNLIKELY((obj->stm_flags & _STM_GCFLAG_WRITE_BARRIER) != 0))
- _stm_write_slowpath_card(obj, index);
+ if (UNLIKELY((obj->stm_flags & _STM_GCFLAG_WRITE_BARRIER) != 0)) {
+ if (LIKELY((obj->stm_flags & _STM_GCFLAG_CARDS_SET) != 0)) {
+ /* XXX: check how well clang optimizes this */
+ _stm_mark_card(obj, index);
+ } else {
+ _stm_write_slowpath_card(obj, index);
+ }
+ }
}
/* Must be provided by the user of this library.
_______________________________________________
pypy-commit mailing list
pypy-commit@python.org
https://mail.python.org/mailman/listinfo/pypy-commit
