In 647982bb71 (delta-islands: free island_marks and bitmaps, 2023-02-03)
we have introduced logic to free `island_marks` in order to reduce heap
memory usage in git-pack-objects(1). This commit is causing segfaults in
the case where this Git command does not load delta islands at all, e.g.
when reading object IDs from standard input. One such crash can be hit
when using repacking multi-pack-indices with delta islands enabled.
The root cause of this bug is that we unconditionally dereference the
`island_marks` variable even in the case where it is a `NULL` pointer,
which is fixed by making it conditional. Note that we still leave the
logic in place to set the pointer to `-1` to detect use-after-free bugs
even when there are no loaded island marks at all.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Acked-by: Eric Wong <e@80x24.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
On my mirror of linux.git forkgroup with 780 islands, this saves
nearly 4G of heap memory in pack-objects. This savings only
benefits delta island users of pack bitmaps, as the process
would otherwise be exiting anyways.
However, there's probably not many delta island users, but the
majority of delta island users would also be pack bitmaps users.
Signed-off-by: Eric Wong <e@80x24.org>
Helped-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Helped-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
On my use case involving 771 islands of Linux on kernel.org,
this reduces memory usage by around 25MB. The bulk of that
comes from free_remote_islands, since free_config_regexes only
saves around 40k.
This memory is saved early in the memory-intensive pack process,
making it available for the remainder of the long process.
Signed-off-by: Eric Wong <e@80x24.org>
Co-authored-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
As reported in [1] the "UNUSED(var)" macro introduced in
2174b8c75de (Merge branch 'jk/unused-annotation' into next,
2022-08-24) breaks coccinelle's parsing of our sources in files where
it occurs.
Let's instead partially go with the approach suggested in [2] of
making this not take an argument. As noted in [1] "coccinelle" will
ignore such tokens in argument lists that it doesn't know about, and
it's less of a surprise to syntax highlighters.
This undoes the "help us notice when a parameter marked as unused is
actually use" part of 9b24034754 (git-compat-util: add UNUSED macro,
2022-08-19), a subsequent commit will further tweak the macro to
implement a replacement for that functionality.
1. https://lore.kernel.org/git/220825.86ilmg4mil.gmgdl@evledraar.gmail.com/
2. https://lore.kernel.org/git/220819.868rnk54ju.gmgdl@evledraar.gmail.com/
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The callback passed to git_config() must conform to a particular
interface. But most callbacks don't actually look at the extra "void
*data" parameter. Let's mark the unused parameters to make
-Wunused-parameter happy.
Note there's one unusual case here in get_remote_default() where we
actually ignore the "value" parameter. That's because it's only checking
whether the option is found at all, and not parsing its value.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Functions used with for_each_ref(), etc, need to conform to the
each_ref_fn interface. But most of them don't need every parameter;
let's annotate the unused ones to quiet -Wunused-parameter.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We renamed the actual data structure in 910650d2f8 (Rename sha1_array to
oid_array, 2017-03-31), but the file is still called sha1-array. Besides
being slightly confusing, it makes it more annoying to grep for leftover
occurrences of "sha1" in various files, because the header is included
in so many places.
Let's complete the transition by renaming the source and header files
(and fixing up a few comment references).
I kept the "-" in the name, as that seems to be our style; cf.
fc1395f4a4 (sha1_file.c: rename to use dash in file name, 2018-04-10).
We also have oidmap.h and oidset.h without any punctuation, but those
are "struct oidmap" and "struct oidset" in the code. We _could_ make
this "oidarray" to match, but somehow it looks uglier to me because of
the length of "array" (plus it would be a very invasive patch for little
gain).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Code clean-up to remove hardcoded SHA-1 hash from many places.
* jk/oidhash:
hashmap: convert sha1hash() to oidhash()
hash.h: move object_id definition from cache.h
khash: rename oid helper functions
khash: drop sha1-specific map types
pack-bitmap: convert khash_sha1 maps into kh_oid_map
delta-islands: convert island_marks khash to use oids
khash: rename kh_oid_t to kh_oid_set
khash: drop broken oid_map typedef
object: convert create_object() to use object_id
object: convert internal hash_obj() to object_id
object: convert lookup_object() to use object_id
object: convert lookup_unknown_object() to use object_id
pack-objects: convert locate_object_entry_hash() to object_id
pack-objects: convert packlist_find() to use object_id
pack-bitmap-write: convert some helpers to use object_id
upload-pack: rename a "sha1" variable to "oid"
describe: fix accidental oid/hash type-punning
The delta island code always prints "Marked %d islands", even if
progress has been suppressed with --no-progress or by sending stderr to
a non-tty.
Let's pass a progress boolean to load_delta_islands(). We already do
the same thing for the progress meter in resolve_tree_islands().
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
All of the users of this map have an actual "struct object_id" rather
than a bare sha1. Let's use the more descriptive type (and get one step
closer to dropping khash_sha1 entirely).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
There are no callers left of lookup_object() that aren't just passing us
the "hash" member of a "struct object_id". Let's take the whole struct,
which gets us closer to removing all raw sha1 variables. It also
matches the existing conversions of lookup_blob(), etc.
The conversions of callers were done by hand, but they're all mechanical
one-liners.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When parsing a tree, we read the object ID directly out of the tree
buffer. This is normally fine, but such an object ID cannot be used with
oidcpy, which copies GIT_MAX_RAWSZ bytes, because if we are using SHA-1,
there may not be that many bytes to copy.
Instead, store the object ID in a separate struct member. Since we can
no longer efficiently compute the path length, store that information as
well in struct name_entry. Ensure we only copy the object ID into the
new buffer if the path length is nonzero, as some callers will pass us
an empty path with no object ID following it, and we will not want to
read past the end of the buffer.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This reduces the size of 'struct object_entry' from 88 bytes
to 80 and therefore makes packing objects more efficient.
For example on a Linux repo with 12M objects,
`git pack-objects --all` needs extra 96MB memory even if the
layer feature is not used.
Helped-by: Jeff King <peff@peff.net>
Helped-by: Duy Nguyen <pclouds@gmail.com>
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This reduces the size of 'struct object_entry' and therefore
makes packing objects more efficient.
This also renames cmp_tree_depth() into tree_depth_compare(),
as it is more modern to have the name of the compare functions
end with "compare".
Helped-by: Jeff King <peff@peff.net>
Helped-by: Duy Nguyen <pclouds@gmail.com>
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Hosting providers that allow users to "fork" existing
repos want those forks to share as much disk space as
possible.
Alternates are an existing solution to keep all the
objects from all the forks into a unique central repo,
but this can have some drawbacks. Especially when
packing the central repo, deltas will be created
between objects from different forks.
This can make cloning or fetching a fork much slower
and much more CPU intensive as Git might have to
compute new deltas for many objects to avoid sending
objects from a different fork.
Because the inefficiency primarily arises when an
object is deltified against another object that does
not exist in the same fork, we partition objects into
sets that appear in the same fork, and define
"delta islands". When finding delta base, we do not
allow an object outside the same island to be
considered as its base.
So "delta islands" is a way to store objects from
different forks in the same repo and packfile without
having deltas between objects from different forks.
This patch implements the delta islands mechanism in
"delta-islands.{c,h}", but does not yet make use of it.
A few new fields are added in 'struct object_entry'
in "pack-objects.h" though.
The documentation will follow in a patch that actually
uses delta islands in "builtin/pack-objects.c".
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Patrick Steinhardt
Eric Wong
Ævar Arnfjörð Bjarmason
Jeff King
Junio C Hamano
brian m. carlson
Nguyễn Thái Ngọc Duy
Christian Couder