Share packs across repository instancescmn/global-mwf

Opening the same repository multiple times will currently open the same
file multiple times, as well as map the same region of the file multiple
times. This is not necessary, as the packfile data is immutable.

Instead of opening and closing packfiles directly, introduce an
indirection and allocate packfiles globally. This does mean locking on
each packfile open, but we already use this lock for the global mwindow
list so it doesn't introduce a new contention point.

1 files changed, 6 insertions, 3 deletions

diff --git a/src/odb_pack.c b/src/odb_pack.c
index 3750da37f..1757cf920 100644
--- a/src/odb_pack.c
+++ b/src/odb_pack.c
@@ -210,7 +210,7 @@ static int packfile_load__cb(void *data, git_buf *path)
 			return 0;
 	}
 
-	error = git_packfile_alloc(&pack, path->ptr);
+	error = git_mwindow_get_pack(&pack, path->ptr);
 
 	/* ignore missing .pack file as git does */
 	if (error == GIT_ENOTFOUND) {
@@ -605,7 +605,7 @@ static void pack_backend__free(git_odb_backend *_backend)
 
 	for (i = 0; i < backend->packs.length; ++i) {
 		struct git_pack_file *p = git_vector_get(&backend->packs, i);
-		git_packfile_free(p);
+		git_mwindow_put_pack(p);
 	}
 
 	git_vector_free(&backend->packs);
@@ -647,7 +647,7 @@ int git_odb_backend_one_pack(git_odb_backend **backend_out, const char *idx)
 	if (pack_backend__alloc(&backend, 1) < 0)
 		return -1;
 
-	if (git_packfile_alloc(&packfile, idx) < 0 ||
+	if (git_mwindow_get_pack(&packfile, idx) < 0 ||
 		git_vector_insert(&backend->packs, packfile) < 0)
 	{
 		pack_backend__free((git_odb_backend *)backend);
@@ -664,6 +664,9 @@ int git_odb_backend_pack(git_odb_backend **backend_out, const char *objects_dir)
 	struct pack_backend *backend = NULL;
 	git_buf path = GIT_BUF_INIT;
 
+	if (git_mwindow_files_init() < 0)
+		return -1;
+
 	if (pack_backend__alloc(&backend, 8) < 0)
 		return -1;