make object_directory.loose_objects_subdir_seen a bitmap
There's no point in using 8 bits per-directory when 1 bit
will do. This saves us 224 bytes per object directory, which
ends up being 22MB when dealing with 100K alternates.
Signed-off-by: Eric Wong <e@80x24.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/object-file.c b/object-file.c
index 2dd70dd..91ded8c 100644
--- a/object-file.c
+++ b/object-file.c
@@ -2461,12 +2461,17 @@
{
int subdir_nr = oid->hash[0];
struct strbuf buf = STRBUF_INIT;
+ size_t word_bits = bitsizeof(odb->loose_objects_subdir_seen[0]);
+ size_t word_index = subdir_nr / word_bits;
+ size_t mask = 1 << (subdir_nr % word_bits);
+ uint32_t *bitmap;
if (subdir_nr < 0 ||
- subdir_nr >= ARRAY_SIZE(odb->loose_objects_subdir_seen))
+ subdir_nr >= bitsizeof(odb->loose_objects_subdir_seen))
BUG("subdir_nr out of range");
- if (odb->loose_objects_subdir_seen[subdir_nr])
+ bitmap = &odb->loose_objects_subdir_seen[word_index];
+ if (*bitmap & mask)
return &odb->loose_objects_cache[subdir_nr];
strbuf_addstr(&buf, odb->path);
@@ -2474,7 +2479,7 @@
append_loose_object,
NULL, NULL,
&odb->loose_objects_cache[subdir_nr]);
- odb->loose_objects_subdir_seen[subdir_nr] = 1;
+ *bitmap |= mask;
strbuf_release(&buf);
return &odb->loose_objects_cache[subdir_nr];
}
diff --git a/object-store.h b/object-store.h
index 6077065..ab6d469 100644
--- a/object-store.h
+++ b/object-store.h
@@ -22,7 +22,7 @@
*
* Be sure to call odb_load_loose_cache() before using.
*/
- char loose_objects_subdir_seen[256];
+ uint32_t loose_objects_subdir_seen[8]; /* 256 bits */
struct oid_array loose_objects_cache[256];
/*
