A result from opendir() was leaking in the commit-graph expiration
codepath, which has been plugged.
* ml/commit-graph-expire-dir-leak-fix:
commit-graph: Fix missing closedir in expire_commit_graphs
The function calls opendir() but missing the corresponding
closedir() before exit the function.
Add missing closedir() to fix it.
Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
Reviewed-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Undoes 'jk/unused-annotation' topic and redoes it to work around
Coccinelle rules misfiring false positives in unrelated codepaths.
* ab/unused-annotation:
git-compat-util.h: use "deprecated" for UNUSED variables
git-compat-util.h: use "UNUSED", not "UNUSED(var)"
Annotate function parameters that are not used (but cannot be
removed for structural reasons), to prepare us to later compile
with -Wunused warning turned on.
* jk/unused-annotation:
is_path_owned_by_current_uid(): mark "report" parameter as unused
run-command: mark unused async callback parameters
mark unused read_tree_recursive() callback parameters
hashmap: mark unused callback parameters
config: mark unused callback parameters
streaming: mark unused virtual method parameters
transport: mark bundle transport_options as unused
refs: mark unused virtual method parameters
refs: mark unused reflog callback parameters
refs: mark unused each_ref_fn parameters
git-compat-util: add UNUSED macro
"git rev-list --verify-objects" ought to inspect the contents of
objects and notice corrupted ones, but it didn't when the commit
graph is in use, which has been corrected.
* jk/rev-list-verify-objects-fix:
rev-list: disable commit graph with --verify-objects
lookup_commit_in_graph(): use prepare_commit_graph() to check for graph
We exit early from lookup_commit_in_graph() if the commit_graph pointer
is NULL, under the assumption that we don't have a graph to look at. But
the graph pointer is lazy-loaded; if no other code happens to have
called prepare_commit_graph(), we'll incorrectly assume that one isn't
available at all.
This has a pretty small performance impact in practice, because the
fallback will generally be to call parse_object() instead. That ends up
in parse_commit_buffer(), which loads the graph data itself. So the
first commit we see won't use the graph, but subsequent ones will. Since
using the graph is just an optimization there's generally no
user-visible difference, but if you instrument rev-list like so:
diff --git a/revision.c b/revision.c
index ee702e498a..63c488ffb6 100644
--- a/revision.c
+++ b/revision.c
@@ -381,6 +381,9 @@ static struct object *get_reference(struct rev_info *revs, const char *name,
* parsing commit data from disk.
*/
commit = lookup_commit_in_graph(revs->repo, oid);
+ warning("%s %s in commit graph",
+ commit ? "found" : "did not find",
+ name);
if (commit)
object = &commit->object;
else
and run (in git.git):
git commit-graph write --reachable
git rev-list origin/master origin/next >/dev/null
you'll see that we fail to find the first one:
warning: did not find origin/master in commit graph
warning: found origin/next in commit graph
After this patch, you'll see that we find both:
warning: found origin/master in commit graph
warning: found origin/next in commit graph
Even though the performance implication is small here, there are two
important reasons to do this:
- it's downright confusing if you are hunting a bug triggered by the
use of the commit graph. It may or may not trigger depending on the
number and ordering of tips you ask for.
- prepare_commit_graph() has other policy logic, too. In particular,
if we've loaded a commit graph and then disabled the graph via
disable_commit_graph(), that should take precedence.
I'm not sure if this can trigger bad behavior in practice. The only
caller there is upload-pack's deepen_by_rev_list(), which should be
avoiding the commit graph for its traversal tips, but probably
wasn't before this patch. Whether you could come up with a case
where that mattered is unclear. Still, this is obviously the right
thing to be doing.
Signed-off-by: Jeff King <peff@peff.net>
Reviewed-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
As reported in [1] the "UNUSED(var)" macro introduced in
2174b8c75d (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>
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>
There was a bug in the codepath to upgrade generation information
in commit-graph from v1 to v2 format, which has been corrected.
source: <cover.1657667404.git.me@ttaylorr.com>
* tb/commit-graph-genv2-upgrade-fix:
commit-graph: fix corrupt upgrade from generation v1 to v2
commit-graph: introduce `repo_find_commit_pos_in_graph()`
t5318: demonstrate commit-graph generation v2 corruption
A corner case bug where lazily fetching objects from a promisor
remote resulted in infinite recursion has been corrected.
source: <cover.1656593279.git.hanxin.hx@bytedance.com>
* hx/lookup-commit-in-graph-fix:
t5330: remove run_with_limited_processses()
commit-graph.c: no lazy fetch in lookup_commit_in_graph()
There was a bug in the codepath to upgrade generation information
in commit-graph from v1 to v2 format, which has been corrected.
* tb/commit-graph-genv2-upgrade-fix:
commit-graph: fix corrupt upgrade from generation v1 to v2
commit-graph: introduce `repo_find_commit_pos_in_graph()`
t5318: demonstrate commit-graph generation v2 corruption
API tweak to make it easier to run fuzz testing on commit-graph parser.
* js/commit-graph-parsing-without-repo-settings:
commit-graph: pass repo_settings instead of repository
A corner case bug where lazily fetching objects from a promisor
remote resulted in infinite recursion has been corrected.
* hx/lookup-commit-in-graph-fix:
t5330: remove run_with_limited_processses()
commit-graph.c: no lazy fetch in lookup_commit_in_graph()
Low-level callers in systems that are adjacent to the commit-graph (like
the changed-path Bloom filter code) could benefit from being able to
call a function like `parse_commit_in_graph()` without modifying the
corresponding commit slab data.
This is useful in contexts where that slab data is being used to prepare
for an upcoming commit-graph write, where Git must be careful to avoid
clobbering any of that data during a read operation.
Introduce a low-level variant of `parse_commit_in_graph()` which returns
the graph position of a given commit only, without modifying any of the
slab data.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The parse_commit_graph() function takes a 'struct repository *' pointer,
but it only ever accesses config settings (either directly or through
the .settings field of the repo struct). Move all relevant config
settings into the repo_settings struct, and update parse_commit_graph()
and its existing callers so that it takes 'struct repo_settings *'
instead.
Callers of parse_commit_graph() will now need to call
prepare_repo_settings() themselves, or initialize a 'struct
repo_settings' directly.
Prior to ab14d0676c (commit-graph: pass a 'struct repository *' in more
places, 2020-09-09), parsing a commit-graph was a pure function
depending only on the contents of the commit-graph itself. Commit
ab14d0676c introduced a dependency on a `struct repository` pointer, and
later commits such as b66d84756f (commit-graph: respect
'commitGraph.readChangedPaths', 2020-09-09) added dependencies on config
settings, which were accessed through the `settings` field of the
repository pointer. This field was initialized via a call to
`prepare_repo_settings()`.
Additionally, this fixes an issue in fuzz-commit-graph: In 44c7e62
(2021-12-06, repo-settings:prepare_repo_settings only in git repos),
prepare_repo_settings was changed to issue a BUG() if it is called by a
process whose CWD is not a Git repository.
The combination of commits mentioned above broke fuzz-commit-graph,
which attempts to parse arbitrary fuzzing-engine-provided bytes as a
commit graph file. Prior to this change, parse_commit_graph() called
prepare_repo_settings(), but since we run the fuzz tests without a valid
repository, we are hitting the BUG() from 44c7e62 for every test case.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Josh Steadmon <steadmon@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The commit-graph is used to opportunistically optimize accesses to
certain pieces of information on commit objects, and
lookup_commit_in_graph() tries to say "no" when the requested commit
does not locally exist by returning NULL, in which case the caller
can ask for (which may result in on-demand fetching from a promisor
remote) and parse the commit object itself.
However, it uses a wrong helper, repo_has_object_file(), to do so.
This helper not only checks if an object is mmediately available in
the local object store, but also tries to fetch from a promisor remote.
But the fetch machinery calls lookup_commit_in_graph(), thus causing an
infinite loop.
We should make lookup_commit_in_graph() expect that a commit given to it
can be legitimately missing from the local object store, by using the
has_object_file() helper instead.
Signed-off-by: Han Xin <hanxin.hx@bytedance.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A mechanism to pack unreachable objects into a "cruft pack",
instead of ejecting them into loose form to be reclaimed later, has
been introduced.
* tb/cruft-packs:
sha1-file.c: don't freshen cruft packs
builtin/gc.c: conditionally avoid pruning objects via loose
builtin/repack.c: add cruft packs to MIDX during geometric repack
builtin/repack.c: use named flags for existing_packs
builtin/repack.c: allow configuring cruft pack generation
builtin/repack.c: support generating a cruft pack
builtin/pack-objects.c: --cruft with expiration
reachable: report precise timestamps from objects in cruft packs
reachable: add options to add_unseen_recent_objects_to_traversal
builtin/pack-objects.c: --cruft without expiration
builtin/pack-objects.c: return from create_object_entry()
t/helper: add 'pack-mtimes' test-tool
pack-mtimes: support writing pack .mtimes files
chunk-format.h: extract oid_version()
pack-write: pass 'struct packing_data' to 'stage_tmp_packfiles'
pack-mtimes: support reading .mtimes files
Documentation/technical: add cruft-packs.txt
There are three definitions of an identical function which converts
`the_hash_algo` into either 1 (for SHA-1) or 2 (for SHA-256). There is a
copy of this function for writing both the commit-graph and
multi-pack-index file, and another inline definition used to write the
.rev header.
Consolidate these into a single definition in chunk-format.h. It's not
clear that this is the best header to define this function in, but it
should do for now.
(Worth noting, the .rev caller expects a 4-byte unsigned, but the other
two callers work with a single unsigned byte. The consolidated version
uses the latter type, and lets the compiler widen it when required).
Another caller will be added in a subsequent patch.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A bit of test framework fixes with a few fixes to issues found by
valgrind.
* ab/valgrind-fixes:
commit-graph.c: don't assume that stat() succeeds
object-file: fix a unpack_loose_header() regression in 3b6a8db3b0
log test: skip a failing mkstemp() test under valgrind
tests: using custom GIT_EXEC_PATH breaks --valgrind tests
Introduce and apply coccinelle rule to discourage an explicit
comparison between a pointer and NULL, and applies the clean-up to
the maintenance track.
* ep/maint-equals-null-cocci:
tree-wide: apply equals-null.cocci
tree-wide: apply equals-null.cocci
contrib/coccinnelle: add equals-null.cocci
Fix code added in 8d84097f96 (commit-graph: expire commit-graph
files, 2019-06-18) to check the return value of the stat() system
call. Not doing so caused us to use uninitialized memory in the "Bloom
generation is limited by --max-new-filters" test in
t4216-log-bloom.sh:
+ rm -f trace.event
+ pwd
+ GIT_TRACE2_EVENT=[...]/t/trash directory.t4216-log-bloom/limits/trace.event git commit-graph write --reachable --split=replace --changed-paths --max-new-filters=2
==24835== Syscall param utimensat(times[0].tv_sec) points to uninitialised byte(s)
==24835== at 0x499E65A: __utimensat64_helper (utimensat.c:34)
==24835== by 0x4999142: utime (utime.c:36)
==24835== by 0x552BE0: mark_commit_graphs (commit-graph.c:2213)
==24835== by 0x550822: write_commit_graph (commit-graph.c:2424)
==24835== by 0x54E3A0: write_commit_graph_reachable (commit-graph.c:1681)
==24835== by 0x4374BB: graph_write (commit-graph.c:269)
==24835== by 0x436F7D: cmd_commit_graph (commit-graph.c:326)
==24835== by 0x407B9A: run_builtin (git.c:465)
==24835== by 0x406651: handle_builtin (git.c:719)
==24835== by 0x407575: run_argv (git.c:786)
==24835== by 0x406410: cmd_main (git.c:917)
==24835== by 0x511F09: main (common-main.c:56)
==24835== Address 0x1ffeffde70 is on thread 1's stack
==24835== in frame #1, created by utime (utime.c:25)
==24835== Uninitialised value was created by a stack allocation
==24835== at 0x552B50: mark_commit_graphs (commit-graph.c:2201)
==24835==
[...]
error: last command exited with $?=126
not ok 137 - Bloom generation is limited by --max-new-filters
This would happen as we stat'd the non-existing
".git/objects/info/commit-graph" file. Let's fix mark_commit_graphs()
to check the stat()'s return value, and while we're at it fix another
case added in the same commit to do the same.
The caller in expire_commit_graphs() would have been less likely to
run into this, as it's operating on files it just got from readdir(),
but it could still happen due to a race with e.g. a concurrent "rm
-rf" of the commit-graph files.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
There are two reasons that we could return NULL early within
load_commit_graph_chain():
1. The file does not exist, so the file pointer is NULL.
2. The file exists, but is too small to contain a single hash.
These were grouped together when the function was first written in
5c84b3396 (commit-graph: load commit-graph chains, 2019-06-18) in order
to simplify how the 'chain_name' string is freed. However, the current
code leaves a narrow window where the file pointer is not closed when
the file exists, but is rejected for being too small.
Split out these cases separately to ensure we close the file in this
case.
Signed-off-by: Kleber Tarcísio <klebertarcisio@yahoo.com.br>
Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Replace core.fsyncObjectFiles with two new configuration variables,
core.fsync and core.fsyncMethod.
* ns/core-fsyncmethod:
core.fsync: documentation and user-friendly aggregate options
core.fsync: new option to harden the index
core.fsync: add configuration parsing
core.fsync: introduce granular fsync control infrastructure
core.fsyncmethod: add writeout-only mode
wrapper: make inclusion of Windows csprng header tightly scoped
Count string_list items in size_t, not "unsigned int".
* ab/string-list-count-in-size-t:
string-list API: change "nr" and "alloc" to "size_t"
gettext API users: don't explicitly cast ngettext()'s "n"
Fixes to the way generation number v2 in the commit-graph files are
(not) handled.
* ds/commit-graph-gen-v2-fixes:
commit-graph: declare bankruptcy on GDAT chunks
commit-graph: fix generation number v2 overflow values
commit-graph: start parsing generation v2 (again)
commit-graph: fix ordering bug in generation numbers
t5318: extract helpers to lib-commit-graph.sh
test-read-graph: include extra post-parse info
This commit introduces the infrastructure for the core.fsync
configuration knob. The repository components we want to sync
are identified by flags so that we can turn on or off syncing
for specific components.
If core.fsyncObjectFiles is set and the core.fsync configuration
also includes FSYNC_COMPONENT_LOOSE_OBJECT, we will fsync any
loose objects. This picks the strictest data integrity behavior
if core.fsync and core.fsyncObjectFiles are set to conflicting values.
This change introduces the currently unused fsync_component
helper, which will be used by a later patch that adds fsyncing to
the refs backend.
Actual configuration and documentation of the fsync components
list are in other patches in the series to separate review of
the underlying mechanism from the policy of how it's configured.
Helped-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Neeraj Singh <neerajsi@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Change the "nr" and "alloc" members of "struct string_list" to use
"size_t" instead of "nr". On some platforms the size of an "unsigned
int" will be smaller than a "size_t", e.g. a 32 bit unsigned v.s. 64
bit unsigned. As "struct string_list" is a generic API we use in a lot
of places this might cause overflows.
As one example: code in "refs.c" keeps track of the number of refs
with a "size_t", and auxiliary code in builtin/remote.c in
get_ref_states() appends those to a "struct string_list".
While we're at it split the "nr" and "alloc" in string-list.h across
two lines, which is the case for most such struct member
declarations (e.g. in "strbuf.h" and "strvec.h").
Changing e.g. "int i" to "size_t i" in run_and_feed_hook() isn't
strictly necessary, and there are a lot more cases where we'll use a
local "int", "unsigned int" etc. variable derived from the "nr" in the
"struct string_list". But in that case as well as
add_wrapped_shortlog_msg() in builtin/shortlog.c we need to adjust the
printf format referring to "nr" anyway, so let's also change the other
variables referring to it.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The Generation Data (GDAT) and Generation Data Overflow (GDOV) chunks
store corrected commit date offsets, used for generation number v2.
Recent changes have demonstrated that previous versions of Git were
incorrectly parsing data from these chunks, but might have also been
writing them incorrectly.
I asserted [1] that the previous fixes were sufficient because the known
reasons for incorrectly writing generation number v2 data relied on
parsing the information incorrectly out of a commit-graph file, but the
previous versions of Git were not reading the generation number v2 data.
However, Patrick demonstrated [2] a case where in split commit-graphs
across an alternate boundary (and possibly some other special
conditions) it was possible to have a commit-graph that was generated by
a previous version of Git have incorrect generation number v2 data which
results in errors like the following:
commit-graph generation for commit <oid> is 1623273624 < 1623273710
[1] https://lore.kernel.org/git/f50e74f0-9ffa-f4f2-4663-269801495ed3@github.com/
[2] https://lore.kernel.org/git/Yh93vOkt2DkrGPh2@ncase/
Clearly, there is something else going on. The situation is not
completely understood, but the errors do not reproduce if the
commit-graphs are all generated by a Git version including these recent
fixes.
If we cannot trust the existing data in the GDAT and GDOV chunks, then
we can alter the format to change the chunk IDs for these chunks. This
causes the new version of Git to silently ignore the older chunks (and
disabling generation number v2 in the process) while writing new
commit-graph files with correct data in the GDA2 and GDO2 chunks.
Update commit-graph-format.txt including a historical note about these
deprecated chunks.
Reported-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Fix a memory leak in code added in 6c622f9f0b (commit-graph: write
commit-graph chains, 2019-06-18). We needed to free the "lock_name" if
we encounter errors, and the "graph_name" after we'd run unlink() on
it.
For the case of write_commit_graph_file() refactoring the code to free
the "lock_name" after we were done using the "struct lock_file lk"
would have made the control flow more complex. Luckily we can free the
"lock_file" right after the hold_lock_file_for_update() call, if it
makes use of "path" at all it'll have copied its contents to a "struct
strbuf" of its own.
While I'm at it let's fix code added in fb10ca5b54 (sparse-checkout:
write using lockfile, 2019-11-21) in write_patterns_and_update() to
avoid the same complexity that I thought I needed when I wrote the
initial fix for write_commit_graph_file(). We can free the
"sparse_filename" right after calling hold_lock_file_for_update(), we
don't need to wait until we're exiting the function to do so.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Fix a bug in fill_oids_from_packs(), we should always stop_progress(),
but did not do so if we returned an error here. This also plugs a
memory leak in those cases by releasing the two "struct strbuf"
variables the function uses.
While I'm at it stop hardcoding "-1" here and just use the return
value of error() instead, which happens to be "-1".
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When this code was migrated to the string_list API in
d88b14b3fd (commit-graph: use string-list API for input, 2018-06-27)
it was made to use used both STRING_LIST_INIT_NODUP and a
strbuf_detach() pattern.
Those should not be used together if string_list_clear() is expected
to free the memory, instead we need to either use STRING_LIST_INIT_DUP
with a string_list_append_nodup(), or a STRING_LIST_INIT_NODUP and
manually fiddle with the "strdup_strings" member before calling
string_list_clear(). Let's do the former.
Since "strdup_strings = 1" is set now other code might be broken by
relying on "pack_indexes" not to duplicate it strings, but that
doesn't happen. When we pass this down to write_commit_graph() that
code uses the "struct string_list" without modifying it. Let's add a
"const" to the variable to have the compiler enforce that assumption.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The Generation Data Chunk was implemented and tested in e8b63005c
(commit-graph: implement generation data chunk, 2021-01-16), but the
test was carefully constructed to work on systems with 32-bit dates.
Since the corrected commit date offsets still required more than 31
bits, this triggered writing the generation_data_overflow chunk.
However, upon closer look, the
write_graph_chunk_generation_data_overflow() method writes the offsets
to the chunk (as dictated by the format) but fill_commit_graph_info()
treats the value in the chunk as if it is the full corrected commit date
(not an offset). For some reason, this does not cause an issue when
using the FUTURE_DATE specified in t5318-commit-graph.sh, but it does
show up as a failure in 'git commit-graph verify' if we increase that
FUTURE_DATE to be above four billion.
Fix this error and create a 64-bit timestamp version of the test so we
can test these larger values.
Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The 'read_generation_data' member of 'struct commit_graph' was
introduced by 1fdc383c5 (commit-graph: use generation v2 only if entire
chain does, 2021-01-16). The intention was to avoid using corrected
commit dates if not all layers of a commit-graph had that data stored.
The logic in validate_mixed_generation_chain() at that point incorrectly
initialized read_generation_data to 1 if and only if the tip
commit-graph contained the Corrected Commit Date chunk.
This was "fixed" in 448a39e65 (commit-graph: validate layers for
generation data, 2021-02-02) to validate that read_generation_data was
either non-zero for all layers, or it would set read_generation_data to
zero for all layers.
The problem here is that read_generation_data is not initialized to be
non-zero anywhere!
This change initializes read_generation_data immediately after the chunk
is parsed, so each layer will have its value present as soon as
possible.
The read_generation_data member is used in fill_commit_graph_info() to
determine if we should use the corrected commit date or the topological
levels stored in the Commit Data chunk. Due to this bug, all previous
versions of Git were defaulting to topological levels in all cases!
This can be measured with some performance tests. Using the Linux kernel
as a testbed, I generated a complete commit-graph containing corrected
commit dates and tested the 'new' version against the previous, 'old'
version.
First, rev-list with --topo-order demonstrates a 26% improvement using
corrected commit dates:
hyperfine \
-n "old" "$OLD_GIT rev-list --topo-order -1000 v3.6" \
-n "new" "$NEW_GIT rev-list --topo-order -1000 v3.6" \
--warmup=10
Benchmark 1: old
Time (mean ± σ): 57.1 ms ± 3.1 ms
Range (min … max): 52.9 ms … 62.0 ms 55 runs
Benchmark 2: new
Time (mean ± σ): 45.5 ms ± 3.3 ms
Range (min … max): 39.9 ms … 51.7 ms 59 runs
Summary
'new' ran
1.26 ± 0.11 times faster than 'old'
These performance improvements are due to the algorithmic improvements
given by walking fewer commits due to the higher cutoffs from corrected
commit dates.
However, this comes at a cost. The additional I/O cost of parsing the
corrected commit dates is visible in case of merge-base commands that do
not reduce the overall number of walked commits.
hyperfine \
-n "old" "$OLD_GIT merge-base v4.8 v4.9" \
-n "new" "$NEW_GIT merge-base v4.8 v4.9" \
--warmup=10
Benchmark 1: old
Time (mean ± σ): 110.4 ms ± 6.4 ms
Range (min … max): 96.0 ms … 118.3 ms 25 runs
Benchmark 2: new
Time (mean ± σ): 150.7 ms ± 1.1 ms
Range (min … max): 149.3 ms … 153.4 ms 19 runs
Summary
'old' ran
1.36 ± 0.08 times faster than 'new'
Performance issues like this are what motivated 702110aac (commit-graph:
use config to specify generation type, 2021-02-25).
In the future, we could fix this performance problem by inserting the
corrected commit date offsets into the Commit Date chunk instead of
having that data in an extra chunk.
Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When computing the generation numbers for a commit-graph, we compute
the corrected commit dates and then check if their offsets from the
actual dates is too large to fit in the 32-bit Generation Data chunk.
However, there is a problem with this approach: if we have parsed the
generation data from the previous commit-graph, then we continue the
loop because the corrected commit date is already computed. This causes
an under-count in the number of overflow values.
It is incorrect to add an increment to num_generation_data_overflows
next to this 'continue' statement, because we might start
double-counting commits that are computed because of the depth-first
search walk from a commit with an earlier OID.
Instead, iterate over the full commit list at the end, checking the
offsets to see how many grow beyond the maximum value.
Create a new t5328-commit-graph-64-bit-time.sh test script to handle
special cases of testing 64-bit timestamps. This helps demonstrate this
bug in more cases. It still won't hit all potential cases until the next
change, which reenables reading generation numbers. Use the skip_all
trick from 0a2bfccb9c (t0051: use "skip_all" under !MINGW in
single-test file, 2022-02-04) to make the output clean when run on a
32-bit system.
Helped-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Return early if git directory does not exist. This will protect against
test failures in the upcoming change to BUG in prepare_repo_settings if no
git directory exists.
Signed-off-by: Lessley Dennington <lessleydennington@gmail.com>
Reviewed-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The run-command API has been updated so that the callers can easily
ask the file descriptors open for packfiles to be closed immediately
before spawning commands that may trigger auto-gc.
* js/run-command-close-packs:
Close object store closer to spawning child processes
run_auto_maintenance(): implicitly close the object store
run-command: offer to close the object store before running
run-command: prettify the `RUN_COMMAND_*` flags
pull: release packs before fetching
commit-graph: when closing the graph, also release the slab
The code to show progress indicator in a few code paths did not
cover between 0-100%, which has been corrected.
* ab/progress-users-adjust-counters:
entry: show finer-grained counter in "Filtering content" progress line
commit-graph: fix bogus counter in "Scanning merged commits" progress line
The final value of the counter of the "Scanning merged commits"
progress line is always one less than its expected total, e.g.:
Scanning merged commits: 83% (5/6), done.
This happens because while iterating over an array the loop variable
is passed to display_progress() as-is, but while C arrays (and thus
the loop variable) start at 0 and end at N-1, the progress counter
must end at N. Fix this by passing 'i + 1' to display_progress(), like
most other callsites do.
There's an RFC series to add a GIT_TEST_CHECK_PROGRESS=1 mode[1] which
catches this issue in the 'fetch.writeCommitGraph' and
'fetch.writeCommitGraph with submodules' tests in
't5510-fetch.sh'. The GIT_TEST_CHECK_PROGRESS=1 mode is not part of
this series, but future changes to progress.c may add it or similar
assertions to catch this and similar bugs elsewhere.
1. https://lore.kernel.org/git/20210620200303.2328957-1-szeder.dev@gmail.com/
Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The slab has information about the commit graph. That means that it is
meaningless (and even misleading) when the commit graph was closed.
This seems not to matter currently, but we're about to fix a
Windows-specific bug where `git pull` does not close the object store
before fetching (risking that an implicit auto-gc fails to remove the
now-obsolete pack file(s)), and once we have that bug fix in place, it
does matter: after that bug fix, we will open the object store, do some
stuff with it, then close it, fetch, and then open it again, and do more
stuff. If we close the commit graph without releasing the corresponding
slab, we're hit by a symptom like this in t5520.19:
BUG: commit-reach.c:85: bad generation skip 9223372036854775807
> 3 at 5cd378271655d43a3b4477520014f02213ad1546
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When queueing references in git-rev-list(1), we try to optimize parsing
of commits via the commit-graph. To do so, we first look up the object's
type, and if it is a commit we call `repo_parse_commit()` instead of
`parse_object()`. This is quite inefficient though given that we're
always uncompressing the object header in order to determine the type.
Instead, we can opportunistically search the commit-graph for the object
ID: in case it's found, we know it's a commit and can directly fill in
the commit object without having to uncompress the object header.
Expose a new function `lookup_commit_in_graph()`, which tries to find a
commit in the commit-graph by ID, and convert `get_reference()` to use
this function. This provides a big performance win in cases where we
load references in a repository with lots of references pointing to
commits. The following has been executed in a real-world repository with
about 2.2 million refs:
Benchmark #1: HEAD~: rev-list --unsorted-input --objects --quiet --not --all --not $newrev
Time (mean ± σ): 4.458 s ± 0.044 s [User: 4.115 s, System: 0.342 s]
Range (min … max): 4.409 s … 4.534 s 10 runs
Benchmark #2: HEAD: rev-list --unsorted-input --objects --quiet --not --all --not $newrev
Time (mean ± σ): 3.089 s ± 0.015 s [User: 2.768 s, System: 0.321 s]
Range (min … max): 3.061 s … 3.105 s 10 runs
Summary
'HEAD: rev-list --unsorted-input --objects --quiet --not --all --not $newrev' ran
1.44 ± 0.02 times faster than 'HEAD~: rev-list --unsorted-input --objects --quiet --not --all --not $newrev'
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The function `find_commit_in_graph()` assumes that the caller has passed
an object which was already determined to be a commit given that it will
access the commit's graph position, which is stored in a commit slab. In
a subsequent patch, we want to search for an object ID though without
knowing whether it is a commit or not, which is not currently possible.
Split out the logic to search the commit graph for a given object ID to
prepare for this change. This commit also renames the function to
`find_commit_pos_in_graph()`, which more accurately reflects what this
function does. Furthermore, in order to allow for the searched object ID
to be const, we need to adjust `bsearch_graph()`'s signature to accept a
constant object ID as input, too.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Many "printf"-like helper functions we have have been annotated
with __attribute__() to catch placeholder/parameter mismatches.
* ab/attribute-format:
advice.h: add missing __attribute__((format)) & fix usage
*.h: add a few missing __attribute__((format))
*.c static functions: add missing __attribute__((format))
sequencer.c: move static function to avoid forward decl
*.c static functions: don't forward-declare __attribute__
Add missing __attribute__((format)) function attributes to various
"static" functions that take printf arguments.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Rewrite an existing caller in `git commit-graph verify` to take
advantage of checksum_valid().
Note that the replacement isn't a verbatim cut-and-paste, since the new
function avoids using hashfile at all and instead talks to the_hash_algo
directly, but it is functionally equivalent.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The idea behind struct object_id is that it is supposed to represent the
identifier of a standard Git object or a special pseudo-object like the
all-zeros object ID. In this case, we have file hashes, which, while
similar, are distinct from the identifiers of objects.
Switch these code paths to use an unsigned char array. This is both
more logically consistent and it means that we need not set the
algorithm identifier for the struct object_id.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In the future, we'll want oidread to automatically set the hash
algorithm member for an object ID we read into it, so ensure we use
oidread instead of hashcpy everywhere we're copying a hash value into a
struct object_id.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A new configuration variable has been introduced to allow choosing
which version of the generation number gets used in the
commit-graph file.
* ds/commit-graph-generation-config:
commit-graph: use config to specify generation type
commit-graph: create local repository pointer
Add and apply a semantic patch for converting code that open-codes
CALLOC_ARRAY to use it instead. It shortens the code and infers the
element size automatically.
Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
