mirrors/git
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

builtin/repack.c: make largest pack preferred

Browse Source 
When repacking into a geometric series and writing a multi-pack bitmap,
it is beneficial to have the largest resulting pack be the preferred
object source in the bitmap's MIDX, since selecting the large packs can
lead to fewer broken delta chains and better compression.

Teach 'git repack' to identify this pack and pass it to the MIDX write
machinery in order to mark it as preferred.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Taylor Blau
2021-09-28 21:55:20 -04:00
committed by Junio C Hamano
parent 1d89d88d37
commit 6d08b9d4ca
6 changed files with 78 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

27
builtin/repack.c
View File

@ -423,6 +423,25 @@ static void split_pack_geometry(struct pack_geometry *geometry, int factor)
geometry->split = split;
}
static struct packed_git *get_largest_active_pack(struct pack_geometry *geometry)
{
if (!geometry) {
/*
* No geometry means either an all-into-one repack (in which
* case there is only one pack left and it is the largest) or an
* incremental one.
*
* If repacking incrementally, then we could check the size of
* all packs to determine which should be preferred, but leave
* this for later.
*/
return NULL;
}
if (geometry->split == geometry->pack_nr)
return NULL;
return geometry->pack[geometry->pack_nr - 1];
}
static void clear_pack_geometry(struct pack_geometry *geometry)
{
if (!geometry)
@ -468,10 +487,12 @@ static void midx_included_packs(struct string_list *include,
}
static int write_midx_included_packs(struct string_list *include,
struct pack_geometry *geometry,
int show_progress, int write_bitmaps)
{
struct child_process cmd = CHILD_PROCESS_INIT;
struct string_list_item *item;
struct packed_git *largest = get_largest_active_pack(geometry);
FILE *in;
int ret;
@ -492,6 +513,10 @@ static int write_midx_included_packs(struct string_list *include,
if (write_bitmaps)
strvec_push(&cmd.args, "--bitmap");
if (largest)
strvec_pushf(&cmd.args, "--preferred-pack=%s",
pack_basename(largest));
ret = start_command(&cmd);
if (ret)
return ret;
@ -783,7 +808,7 @@ int cmd_repack(int argc, const char **argv, const char *prefix)
midx_included_packs(&include, &existing_nonkept_packs,
&existing_kept_packs, &names, geometry);
ret = write_midx_included_packs(&include,
ret = write_midx_included_packs(&include, geometry,
show_progress, write_bitmaps > 0);
string_list_clear(&include, 0);