From ef0649a3f075a5bfbbc15612d64b6d4faed9e2ec Mon Sep 17 00:00:00 2001 From: Vlad Brezae Date: Mon, 11 Nov 2024 13:09:19 +0200 Subject: [PATCH] [mono][sgen] Add separate card mark function to be used with debug When marking cards for a non-array object or a an element vt in an object, it is enough to mark a card for any address within that object/vt because they are always fully scanned. Cardtable consistency checks are not accounting for this detail and it is difficult to have it implemented. Instead, when having such debug flags enabled, we use an explicit approach where every single card is being marked. --- src/mono/mono/sgen/sgen-cardtable.c | 32 +++++++++++++++++++++++++++-- src/mono/mono/sgen/sgen-cardtable.h | 2 +- src/mono/mono/sgen/sgen-gc.c | 2 +- 3 files changed, 32 insertions(+), 4 deletions(-) diff --git a/src/mono/mono/sgen/sgen-cardtable.c b/src/mono/mono/sgen/sgen-cardtable.c index 6a662fb605019f..e344ec15fe228f 100644 --- a/src/mono/mono/sgen/sgen-cardtable.c +++ b/src/mono/mono/sgen/sgen-cardtable.c @@ -165,6 +165,31 @@ sgen_card_table_wbarrier_range_copy (gpointer _dest, gconstpointer _src, int siz } } +// Marks more cards so that it works with remset consistency debug checks +static void +sgen_card_table_wbarrier_range_copy_debug (gpointer _dest, gconstpointer _src, int size) +{ + GCObject **dest = (GCObject **)_dest; + GCObject **src = (GCObject **)_src; + + size_t nursery_bits = sgen_nursery_bits; + char *start = sgen_nursery_start; + G_GNUC_UNUSED char *end = sgen_nursery_end; + + while (size) { + GCObject *value = *src; + *dest = value; + if (SGEN_PTR_IN_NURSERY (value, nursery_bits, start, end) || sgen_concurrent_collection_in_progress) { + volatile guint8 *card_address = (volatile guint8 *)sgen_card_table_get_card_address ((mword)dest); + *card_address = 1; + sgen_dummy_use (value); + } + ++src; + ++dest; + size -= SIZEOF_VOID_P; + } +} + MONO_RESTORE_WARNING #ifdef SGEN_HAVE_OVERLAPPING_CARDS @@ -606,7 +631,7 @@ sgen_cardtable_scan_object (GCObject *obj, mword block_obj_size, guint8 *cards, } void -sgen_card_table_init (SgenRememberedSet *remset) +sgen_card_table_init (SgenRememberedSet *remset, gboolean consistency_checks) { sgen_cardtable = (guint8 *)sgen_alloc_os_memory (CARD_COUNT_IN_BYTES, (SgenAllocFlags)(SGEN_ALLOC_INTERNAL | SGEN_ALLOC_ACTIVATE), "card table", MONO_MEM_ACCOUNT_SGEN_CARD_TABLE); @@ -637,7 +662,10 @@ sgen_card_table_init (SgenRememberedSet *remset) remset->find_address = sgen_card_table_find_address; remset->find_address_with_cards = sgen_card_table_find_address_with_cards; - remset->wbarrier_range_copy = sgen_card_table_wbarrier_range_copy; + if (consistency_checks) + remset->wbarrier_range_copy = sgen_card_table_wbarrier_range_copy_debug; + else + remset->wbarrier_range_copy = sgen_card_table_wbarrier_range_copy; need_mod_union = sgen_get_major_collector ()->is_concurrent; } diff --git a/src/mono/mono/sgen/sgen-cardtable.h b/src/mono/mono/sgen/sgen-cardtable.h index 1ea3055fce085d..e07bc2cf5c0348 100644 --- a/src/mono/mono/sgen/sgen-cardtable.h +++ b/src/mono/mono/sgen/sgen-cardtable.h @@ -30,7 +30,7 @@ void sgen_card_table_preclean_mod_union (guint8 *cards, guint8 *cards_preclean, guint8* sgen_get_card_table_configuration (int *shift_bits, gpointer *mask); guint8* sgen_get_target_card_table_configuration (int *shift_bits, target_mgreg_t *mask); -void sgen_card_table_init (SgenRememberedSet *remset); +void sgen_card_table_init (SgenRememberedSet *remset, gboolean consistency_checks); /*How many bytes a single card covers*/ #define CARD_BITS 9 diff --git a/src/mono/mono/sgen/sgen-gc.c b/src/mono/mono/sgen/sgen-gc.c index 5024faa35173cb..5338b9dc5df0a1 100644 --- a/src/mono/mono/sgen/sgen-gc.c +++ b/src/mono/mono/sgen/sgen-gc.c @@ -3895,7 +3895,7 @@ sgen_gc_init (void) memset (&remset, 0, sizeof (remset)); - sgen_card_table_init (&remset); + sgen_card_table_init (&remset, remset_consistency_checks); sgen_register_root (NULL, 0, sgen_make_user_root_descriptor (sgen_mark_normal_gc_handles), ROOT_TYPE_NORMAL, MONO_ROOT_SOURCE_GC_HANDLE, GINT_TO_POINTER (ROOT_TYPE_NORMAL), "GC Handles (SGen, Normal)");