GC: Trim EWAHCompressedBitmaps to free unused memory

The "Building bitmaps" GC phase fails for large repositories (repos with
10M objects use 1.25MB per uncompressed bitmap, and those with long
histories may build >25k bitmaps). Since these bitmaps xor well against
each other, the actual space needed for each compressed bitmap is
usually no more than a few KB. Calling trim() will ensure we aren't
holding on to excess memory.

Change-Id: I40bf78c730b9f6051da6025f9777ce27220a5b0a
Signed-off-by: Terry Parker <tparker@google.com>

diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/PackBitmapIndexBuilder.java b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/PackBitmapIndexBuilder.java
index 70eb10ea8f90185a2b854ba4a91e4bdac2274b25..eff7958748eed694fabfe8820362f6b209ff74b6 100644 (file)
--- a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/PackBitmapIndexBuilder.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/PackBitmapIndexBuilder.java
@@ -351,6 +351,7 @@ public class PackBitmapIndexBuilder extends BasePackBitmapIndex {
                                                PositionEntry entry = positionEntries.get(item);
                                                if (entry == null)
                                                        throw new IllegalStateException();
+                                               bestBitmap.trim();
                                                return new StoredEntry(entry.namePosition, bestBitmap,
                                                                bestXorOffset, item.getFlags());
                                        }

diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/PackBitmapIndexRemapper.java b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/PackBitmapIndexRemapper.java
index c04c90f22f8ac63a07d205acf2b8f27692d5f7f1..70695880d3c3a2a6559575c5357a268743c62b82 100644 (file)
--- a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/PackBitmapIndexRemapper.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/PackBitmapIndexRemapper.java
@@ -200,6 +200,7 @@ public class PackBitmapIndexRemapper extends PackBitmapIndex
                for (IntIterator i = oldBitmap.getBitmap().intIterator(); i.hasNext();)
                        inflated.set(prevToNewMapping[i.next()]);
                bitmap = inflated.toEWAHCompressedBitmap();
+               bitmap.trim();
                convertedBitmaps.add(
                                new StoredBitmap(objectId, bitmap, null, oldBitmap.getFlags()));
                return bitmap;