Set default bitmap-chunksize for internal bitmaps to at least 64Meg

A small bitmap-chunksize hurts performance without helping
resync speed much - particularly on internal bitmaps.

So set the default to at least 64Meg.

Signed-off-by: NeilBrown <neilb@suse.de>

1 files changed, 7 insertions, 2 deletions

diff --git a/super1.c b/super1.c
index a21e7e3..8678e9f 100644
--- a/super1.c
+++ b/super1.c
@@ -1501,9 +1501,14 @@ add_internal_bitmap1(struct supertype *st,
 		min_chunk *= 2;
 		bits = (bits+1)/2;
 	}
-	if (chunk == UnSet)
+	if (chunk == UnSet) {
+		/* For practical purpose, 64Meg is a good
+		 * default chunk size for internal bitmaps.
+		 */
 		chunk = min_chunk;
-	else if (chunk < min_chunk)
+		if (chunk < 64*1024*1024)
+			chunk = 64*1024*1024;
+	} else if (chunk < min_chunk)
 		return 0; /* chunk size too small */
 	if (chunk == 0) /* rounding problem */
 		return 0;