Rework object refs tracking to reduce memory usage

Store pointers to referenced objects in a variable sized array instead
of linked list.  This cuts down memory usage of utilities which use
object references; e.g., git-fsck-objects --full on the git.git
repository consumes about 2 MB of memory tracked by Massif instead of
7 MB before the change.  Object refs are still the biggest consumer of
memory (57%), but the malloc overhead for a single block instead of a
linked list is substantially smaller.

Signed-off-by: Sergey Vlasov <vsu@altlinux.ru>
Signed-off-by: Junio C Hamano <junkio@cox.net>
This commit is contained in:
Sergey Vlasov
2005-11-15 19:08:08 +03:00
committed by Junio C Hamano
parent 545f229a4b
commit 4a4e6fd74f
7 changed files with 117 additions and 43 deletions

View File

@ -204,6 +204,7 @@ int parse_commit_buffer(struct commit *item, void *buffer, unsigned long size)
unsigned char parent[20];
struct commit_list **pptr;
struct commit_graft *graft;
unsigned n_refs = 0;
if (item->object.parsed)
return 0;
@ -214,7 +215,7 @@ int parse_commit_buffer(struct commit *item, void *buffer, unsigned long size)
return error("bad tree pointer in commit %s\n", sha1_to_hex(item->object.sha1));
item->tree = lookup_tree(parent);
if (item->tree)
add_ref(&item->object, &item->tree->object);
n_refs++;
bufptr += 46; /* "tree " + "hex sha1" + "\n" */
pptr = &item->parents;
@ -230,7 +231,7 @@ int parse_commit_buffer(struct commit *item, void *buffer, unsigned long size)
new_parent = lookup_commit(parent);
if (new_parent) {
pptr = &commit_list_insert(new_parent, pptr)->next;
add_ref(&item->object, &new_parent->object);
n_refs++;
}
}
if (graft) {
@ -241,10 +242,22 @@ int parse_commit_buffer(struct commit *item, void *buffer, unsigned long size)
if (!new_parent)
continue;
pptr = &commit_list_insert(new_parent, pptr)->next;
add_ref(&item->object, &new_parent->object);
n_refs++;
}
}
item->date = parse_commit_date(bufptr);
if (track_object_refs) {
unsigned i = 0;
struct commit_list *p;
struct object_refs *refs = alloc_object_refs(n_refs);
if (item->tree)
refs->ref[i++] = &item->tree->object;
for (p = item->parents; p; p = p->next)
refs->ref[i++] = &p->item->object;
set_object_refs(&item->object, refs);
}
return 0;
}