Shrink "struct object" a bit

This shrinks "struct object" by a small amount, by getting rid of the
"struct type *" pointer and replacing it with a 3-bit bitfield instead.

In addition, we merge the bitfields and the "flags" field, which
incidentally should also remove a useless 4-byte padding from the object
when in 64-bit mode.

Now, our "struct object" is still too damn large, but it's now less
obviously bloated, and of the remaining fields, only the "util" (which is
not used by most things) is clearly something that should be eventually
discarded.

This shrinks the "git-rev-list --all" memory use by about 2.5% on the
kernel archive (and, perhaps more importantly, on the larger mozilla
archive). That may not sound like much, but I suspect it's more on a
64-bit platform.

There are other remaining inefficiencies (the parent lists, for example,
probably have horrible malloc overhead), but this was pretty obvious.

Most of the patch is just changing the comparison of the "type" pointer
from one of the constant string pointers to the appropriate new TYPE_xxx
small integer constant.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>

1 files changed, 5 insertions, 5 deletions

diff --git a/fetch-pack.c b/fetch-pack.c
index 8371348556..7d23a8071a 100644
--- a/fetch-pack.c
+++ b/fetch-pack.c
@@ -46,7 +46,7 @@ static int rev_list_insert_ref(const char *path, const unsigned char *sha1)
 {
 	struct object *o = deref_tag(parse_object(sha1), path, 0);
 
-	if (o && o->type == commit_type)
+	if (o && o->type == TYPE_COMMIT)
 		rev_list_push((struct commit *)o, SEEN);
 
 	return 0;
@@ -251,14 +251,14 @@ static int mark_complete(const char *path, const unsigned char *sha1)
 {
 	struct object *o = parse_object(sha1);
 
-	while (o && o->type == tag_type) {
+	while (o && o->type == TYPE_TAG) {
 		struct tag *t = (struct tag *) o;
 		if (!t->tagged)
 			break; /* broken repository */
 		o->flags |= COMPLETE;
 		o = parse_object(t->tagged->sha1);
 	}
-	if (o && o->type == commit_type) {
+	if (o && o->type == TYPE_COMMIT) {
 		struct commit *commit = (struct commit *)o;
 		commit->object.flags |= COMPLETE;
 		insert_by_date(commit, &complete);
@@ -352,7 +352,7 @@ static int everything_local(struct ref **refs, int nr_match, char **match)
 		 * in sync with the other side at some time after
 		 * that (it is OK if we guess wrong here).
 		 */
-		if (o->type == commit_type) {
+		if (o->type == TYPE_COMMIT) {
 			struct commit *commit = (struct commit *)o;
 			if (!cutoff || cutoff < commit->date)
 				cutoff = commit->date;
@@ -371,7 +371,7 @@ static int everything_local(struct ref **refs, int nr_match, char **match)
 		struct object *o = deref_tag(lookup_object(ref->old_sha1),
 					     NULL, 0);
 
-		if (!o || o->type != commit_type || !(o->flags & COMPLETE))
+		if (!o || o->type != TYPE_COMMIT || !(o->flags & COMPLETE))
 			continue;
 
 		if (!(o->flags & SEEN)) {