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[PATCH] delta-islands: free island_marks and bitmaps

From
EWEric Wong <e@80x24.org>
Date
Feb 2, 2023, 01:03 UTC
Message-ID
<20230202010353.23391-1-e@80x24.org>

On my mirror of linux.git forkgroup with 780 islands, this saves nearly 4G of heap memory in pack-objects. This savings only benefits delta island users of pack bitmaps, as the process would otherwise be exiting anyways.

However, there's probably not many delta island users, but the majority of delta island users would also be pack bitmaps users.

Signed-off-by: Eric Wong <e@80x24.org>
---
 Slowly chipping away, this is low-hanging fruit.
 delta-islands.c | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)
diff --git a/delta-islands.c b/delta-islands.c
index 90c0d6958f..7052a3a6ba 100644
--- a/delta-islands.c
+++ b/delta-islands.c
@@ -513,12 +513,29 @@ void propagate_island_marks(struct commit *commit)
 	}
 }
 
+static void free_island_marks(void)
+{
+	struct island_bitmap *bitmap;
+
+	kh_foreach_value(island_marks, bitmap, {
+		if (--bitmap->refcount == 0)
+			free(bitmap);
+	});
+	kh_destroy_oid_map(island_marks);
+	island_marks = (void *)1; /* crash on unintended future use */
+}
+
 int compute_pack_layers(struct packing_data *to_pack)
 {
 	uint32_t i;
 
-	if (!core_island_name || !island_marks)
+	if (!island_marks)
+		return 1;
+
+	if (!core_island_name) {
+		free_island_marks();
 		return 1;
+	}
 
 	for (i = 0; i < to_pack->nr_objects; ++i) {
 		struct object_entry *entry = &to_pack->objects[i];
@@ -533,6 +550,7 @@ int compute_pack_layers(struct packing_data *to_pack)
 				oe_set_layer(to_pack, entry, 0);
 		}
 	}
+	free_island_marks();
 
 	return 2;
 }
Next: Ævar Arnfjörð Bjarmason
Message 1 of 6 in “delta-islands: free island_marks and bitmaps”
  1. delta-islands: free island_marks and bitmapsEric Wong, Feb 2, 2023
  2. Ævar Arnfjörð BjarmasonFeb 2, 2023
  3. delta-islands: free island_marks and bitmapsEric Wong, Feb 2, 2023
  4. Jeff KingFeb 3, 2023
  5. delta-islands: free island_marks and bitmapsEric Wong, Feb 3, 2023
  6. Jeff KingFeb 4, 2023

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