The threading model for fscache has been to have a single, global cache.
This puts requirements on it to be thread safe so that callers like
preload-index can call it from multiple threads. This was implemented
with a single mutex and completion events which introduces contention
between the calling threads.
Simplify the threading model by making fscache thread specific. This allows
us to remove the global mutex and synchronization events entirely and instead
associate a fscache with every thread that requests one. This works well with
the current multi-threading which divides the cache entries into blocks with
a separate thread processing each block.
At the end of each worker thread, if there is a fscache on the primary
thread, merge the cached results from the worker into the primary thread
cache. This enables us to reuse the cache later especially when scanning for
untracked files.
In testing, this reduced the time spent in preload_index() by about 25% and
also reduced the CPU utilization significantly. On a repo with ~200K files,
it reduced overall status times by ~12%.
Signed-off-by: Ben Peart <benpeart@microsoft.com>
Update enable_fscache() to take an optional initial size parameter which is
used to initialize the hashmap so that it can avoid having to rehash as
additional entries are added.
Add a separate disable_fscache() macro to make the code clearer and easier
to read.
Signed-off-by: Ben Peart <benpeart@microsoft.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
This is retry of #1419.
I added flush_fscache macro to flush cached stats after disk writing
with tests for regression reported in #1438 and #1442.
git checkout checks each file path in sorted order, so cache flushing does not
make performance worse unless we have large number of modified files in
a directory containing many files.
Using chromium repository, I tested `git checkout .` performance when I
delete 10 files in different directories.
With this patch:
TotalSeconds: 4.307272
TotalSeconds: 4.4863595
TotalSeconds: 4.2975562
Avg: 4.36372923333333
Without this patch:
TotalSeconds: 20.9705431
TotalSeconds: 22.4867685
TotalSeconds: 18.8968292
Avg: 20.7847136
I confirmed this patch passed all tests in t/ with core_fscache=1.
Signed-off-by: Takuto Ikuta <tikuta@chromium.org>
Make fscache_enabled() function public rather than static.
Remove unneeded fscache_is_enabled() function.
Change is_fscache_enabled() macro to call fscache_enabled().
is_fscache_enabled() now takes a pathname so that the answer
is more precise and mean "is fscache enabled for this pathname",
since fscache only stores repo-relative paths and not absolute
paths, we can avoid attempting lookups for absolute paths.
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Teach read_directory_recursive() and add_excludes() to
be aware of optional fscache and avoid trying to open()
and fstat() non-existant ".gitignore" files in every
directory in the worktree.
The current code in add_excludes() calls open() and then
fstat() for a ".gitignore" file in each directory present
in the worktree. Change that when fscache is enabled to
call lstat() first and if present, call open().
This seems backwards because both lstat needs to do more
work than fstat. But when fscache is enabled, fscache will
already know if the .gitignore file exists and can completely
avoid the IO calls. This works because of the lstat diversion
to mingw_lstat when fscache is enabled.
This reduced status times on a 350K file enlistment of the
Windows repo on a NVMe SSD by 0.25 seconds.
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Checking the work tree status is quite slow on Windows, due to slow
`lstat()` emulation (git calls `lstat()` once for each file in the
index). Windows operating system APIs seem to be much better at scanning
the status of entire directories than checking single files.
Add an `lstat()` implementation that uses a cache for lstat data. Cache
misses read the entire parent directory and add it to the cache.
Subsequent `lstat()` calls for the same directory are served directly
from the cache.
Also implement `opendir()`/`readdir()`/`closedir()` so that they create
and use directory listings in the cache.
The cache doesn't track file system changes and doesn't plug into any
modifying file APIs, so it has to be explicitly enabled for git functions
that don't modify the working copy.
Note: in an earlier version of this patch, the cache was always active and
tracked file system changes via ReadDirectoryChangesW. However, this was
much more complex and had negative impact on the performance of modifying
git commands such as 'git checkout'.
Signed-off-by: Karsten Blees <blees@dcon.de>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Add a macro to mark code sections that only read from the file system,
along with a config option and documentation.
This facilitates implementation of relatively simple file system level
caches without the need to synchronize with the file system.
Enable read-only sections for 'git status' and preload_index.
Signed-off-by: Karsten Blees <blees@dcon.de>
This topic vendors in mimalloc v2.0.9, a fast allocator that allows Git
for Windows to perform efficiently.
Switch Git for Windows to using mimalloc instead of nedmalloc
Some platforms (e.g. Windows) provide API functions to resolve paths
much quicker. Let's offer a way to short-cut `strbuf_realpath()` on
those platforms.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
By defining `USE_MIMALLOC`, Git can now be compiled with that
nicely-fast and small allocator.
Note that we have to disable a couple `DEVELOPER` options to build
mimalloc's source code, as it makes heavy use of declarations after
statements, among other things that disagree with Git's conventions.
We even have to silence some GCC warnings in non-DEVELOPER mode. For
example, the `-Wno-array-bounds` flag is needed because in `-O2` builds,
trying to call `NtCurrentTeb()` (which `_mi_thread_id()` does on
Windows) causes the bogus warning about a system header, likely related
to https://sourceforge.net/p/mingw-w64/mailman/message/37674519/ and to
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99578:
C:/git-sdk-64-minimal/mingw64/include/psdk_inc/intrin-impl.h:838:1:
error: array subscript 0 is outside array bounds of 'long long unsigned int[0]' [-Werror=array-bounds]
838 | __buildreadseg(__readgsqword, unsigned __int64, "gs", "q")
| ^~~~~~~~~~~~~~
Also: The `mimalloc` library uses C11-style atomics, therefore we must
require that standard when compiling with GCC if we want to use
`mimalloc` (instead of requiring "only" C99). This is what we do in the
CMake definition already, therefore this commit does not need to touch
`contrib/buildsystems/`.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
We are about to vendor in `mimalloc`'s source code which we will want to
include `git-compat-util.h` after defining that constant.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
It seems to be not exactly rare on Windows to install NTFS junction
points (the equivalent of "bind mounts" on Linux/Unix) in worktrees,
e.g. to map some development tools into a subdirectory.
In such a scenario, it is pretty horrible if `git clean -dfx` traverses
into the mapped directory and starts to "clean up".
Let's just not do that. Let's make sure before we traverse into a
directory that it is not a mount point (or junction).
This addresses https://github.com/git-for-windows/git/issues/607
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Newer regex library macOS stopped enabling GNU-like enhanced BRE,
where '\(A\|B\)' works as alternation, unless explicitly asked with
the REG_ENHANCED flag. "git grep" now can be compiled to do so, to
retain the old behaviour.
* rs/use-enhanced-bre-on-macos:
use enhanced basic regular expressions on macOS
Code cleaning.
* rs/dup-array:
use DUP_ARRAY
add DUP_ARRAY
do full type check in BARF_UNLESS_COPYABLE
factor out BARF_UNLESS_COPYABLE
mingw: make argv2 in try_shell_exec() non-const
Add a macro for allocating and populating a shallow copy of an array.
It is intended to replace a sequence like this:
ALLOC_ARRAY(dst, n);
COPY_ARRAY(dst, src, n);
With the less repetitve:
DUP_ARRAY(dst, src, n);
It checks whether the types of source and destination are compatible to
ensure the copy can be used safely.
An easier alternative would be to only consider the source and return
a void pointer, that could be used like this:
dst = ARRAY_DUP(src, n);
That would be more versatile, as it could be used in declarations as
well. Making it type-safe would require the use of typeof_unqual from
C23, though.
So use the safe and compatible variant for now.
Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Use __builtin_types_compatible_p to perform a full type check if
possible. Otherwise fall back to the old size comparison, but add a
non-evaluated assignment to catch more type mismatches. It doesn't flag
copies between arrays with different signedness, but that's as close to
a full type check as it gets without the builtin, as far as I can see.
Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Move the common basic element type check of COPY_ARRAY and MOVE_ARRAY to
a new macro. This reduces code duplication and simplifies adding more
elaborate checks.
Suggested-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When 1819ad327b (grep: fix multibyte regex handling under macOS,
2022-08-26) started to use the native regex library instead of Git's
own (compat/regex/), it lost support for alternation in basic
regular expressions.
Bring it back by enabling the flag REG_ENHANCED on macOS when
compiling basic regular expressions.
Reported-by: Marco Nenciarini <marco.nenciarini@enterprisedb.com>
Suggested-by: Jeff King <peff@peff.net>
Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Redefining system functions for a few functions did not follow our
usual "implement git_foo() and #define foo(args) git_foo(args)"
pattern, which has broken build for some folks.
* jk/avoid-redef-system-functions-2.30:
git-compat-util: undefine system names before redeclaring them
git-compat-util: avoid redefining system function names
The `%w(width,indent1,indent2)` formatting directive can be used to
rewrap text to a specific width and is designed after git-shortlog(1)'s
`-w` parameter. While the three parameters are all stored as `size_t`
internally, `strbuf_add_wrapped_text()` accepts integers as input. As a
result, the casted integers may overflow. As these now-negative integers
are later on passed to `strbuf_addchars()`, we will ultimately run into
implementation-defined behaviour due to casting a negative number back
to `size_t` again. On my platform, this results in trying to allocate
9000 petabyte of memory.
Fix this overflow by using `cast_size_t_to_int()` so that we reject
inputs that cannot be represented as an integer.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When we define a macro to point a system function (e.g., flockfile) to
our custom wrapper, we should make sure that the system did not already
define it as a macro. This is rarely a problem, but can cause
compilation failures if both of these are true:
- we decide to define our own wrapper even though the system provides
the function; we know this happens at least with uclibc, which may
declare flockfile, etc, without _POSIX_THREAD_SAFE_FUNCTIONS
- the system version is declared as a macro; we know this happens at
least with uclibc's version of getc_unlocked()
So just handling getc_unlocked() would be sufficient to deal with the
real-world case we've seen. But since it's easy to do, we may as well be
defensive about the other macro wrappers added in the previous patch.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Our git-compat-util header defines a few noop wrappers for system
functions if they are not available. This was originally done with a
macro, but in 15b52a44e0 (compat-util: type-check parameters of no-op
replacement functions, 2020-08-06) we switched to inline functions,
because it gives us basic type-checking.
This can cause compilation failures when the system _does_ declare those
functions but we choose not to use them, since the compiler will
complain about the redeclaration. This was seen in the real world when
compiling against certain builds of uclibc, which may leave
_POSIX_THREAD_SAFE_FUNCTIONS unset, but still declare flockfile() and
funlockfile().
It can also be seen on any platform that has setitimer() if you choose
to compile without it (which plausibly could happen if the system
implementation is buggy). E.g., on Linux:
$ make NO_SETITIMER=IWouldPreferNotTo git.o
CC git.o
In file included from builtin.h:4,
from git.c:1:
git-compat-util.h:344:19: error: conflicting types for ‘setitimer’; have ‘int(int, const struct itimerval *, struct itimerval *)’
344 | static inline int setitimer(int which UNUSED,
| ^~~~~~~~~
In file included from git-compat-util.h:234:
/usr/include/x86_64-linux-gnu/sys/time.h:155:12: note: previous declaration of ‘setitimer’ with type ‘int(__itimer_which_t, const struct itimerval * restrict, struct itimerval * restrict)’
155 | extern int setitimer (__itimer_which_t __which,
| ^~~~~~~~~
make: *** [Makefile:2714: git.o] Error 1
Here I think the compiler is complaining about the lack of "restrict"
annotations in our version, but even if we matched it completely (and
there is no way to match all platforms anyway), it would still complain
about a static declaration following a non-static one. Using macros
doesn't have this problem, because the C preprocessor rewrites the name
in our code before we hit this level of compilation.
One way to fix this would just be to revert most of 15b52a44e0. What we
really cared about there was catching build problems with
precompose_argv(), which most platforms _don't_ build, and which is our
custom function. So we could just switch the system wrappers back to
macros; most people build the real versions anyway, and they don't
change. So the extra type-checking isn't likely to catch bugs.
But with a little work, we can have our cake and eat it, too. If we
define the type-checking wrappers with a unique name, and then redirect
the system names to them with macros, we still get our type checking,
but without redeclaring the system function names.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
More UNUSED annotation to help using -Wunused option with the
compiler.
* jk/unused-anno-more:
ll-merge: mark unused parameters in callbacks
diffcore-pickaxe: mark unused parameters in pickaxe functions
convert: mark unused parameter in null stream filter
apply: mark unused parameters in noop error/warning routine
apply: mark unused parameters in handlers
date: mark unused parameters in handler functions
string-list: mark unused callback parameters
object-file: mark unused parameters in hash_unknown functions
mark unused parameters in trivial compat functions
update-index: drop unused argc from do_reupdate()
submodule--helper: drop unused argc from module_list_compute()
diffstat_consume(): assert non-zero length
When a platform feature isn't available or in use, we sometimes
conditionally compile empty or trivial functions to turn these into
noops. We need to annotate their parameters so that -Wunused-parameters
won't complain about them.
Note that there are many more of these in compat/mingw.h, but we'll
leave them for now, as there's some trickery required to get the UNUSED
macro available there.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
With a bit of header twiddling, use the native regexp library on
macOS instead of the compat/ one.
* ds/use-platform-regex-on-macos:
grep: fix multibyte regex handling under macOS
https://gcc.gnu.org/gcc-4.5/changes.html says
The deprecated attribute now takes an optional string argument, for
example, __attribute__((deprecated("text string"))), that will be
printed together with the deprecation warning.
While GCC 4.5 is already 12 years old, git checks for even older
versions in places. Let's not needlessly break older compilers when
a small and simple fix is readily available.
Signed-off-by: Alejandro R. Sedeño <asedeno@mit.edu>
Signed-off-by: Alejandro R Sedeño <asedeno@google.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
Fix deadlocks between main Git process and subprocess spawned via
the pipe_command() API, that can kill "git add -p" that was
reimplemented in C recently.
* jk/pipe-command-nonblock:
pipe_command(): mark stdin descriptor as non-blocking
pipe_command(): handle ENOSPC when writing to a pipe
pipe_command(): avoid xwrite() for writing to pipe
git-compat-util: make MAX_IO_SIZE define globally available
nonblock: support Windows
compat: add function to enable nonblocking pipes
Fix code added in ce125d431a (submodule: extract path to submodule
gitdir func, 2021-09-15) and a77c3fcb5e (submodule--helper: get
remote names from any repository, 2022-03-04) which failed to check
the return values of repo_init() and repo_submodule_init(). If we
failed to initialize the repository or submodule we could segfault
when trying to access the invalid repository structs.
Let's also check that these were the only such logic errors in the
codebase by making use of the "warn_unused_result" attribute. This is
valid as of GCC 3.4.0 (and clang will catch it via its faking of
__GNUC__ ).
As the comment being added to git-compat-util.h we're piggy-backing on
the LAST_ARG_MUST_BE_NULL version check out of lazyness. See
9fe3edc47f (Add the LAST_ARG_MUST_BE_NULL macro, 2013-07-18) for its
addition. The marginal benefit of covering gcc 3.4.0..4.0.0 is
near-zero (or zero) at this point. It mostly matters that we catch
this somewhere.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Reviewed-by: Glen Choo <chooglen@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
As noted in the preceding commit our "UNUSED" macro was no longer
protecting against actual use of the "unused" variables, which it was
previously doing by renaming the variable.
Let's instead use the "deprecated" attribute to accomplish that
goal. As [1] rightly notes this has the drawback that compiling with
"-Wno-deprecated-declarations" will silence any such uses. I think the
trade-off is worth it as:
* We can consider that a feature, as e.g. backporting certain patches
might use a now "unused" parameter, and the person doing that might
want to silence it with DEVOPTS=no-error.
* This way we play nicely with coccinelle, and any other dumb(er)
parser of C (such as syntax highlighters).
* Not every single compilation of git needs to catch "used but
declared unused" parameters. It's sufficient that the default "make
DEVELOPER=1" will do so, and that the "static-analysis" CI job will
catch it.
1. https://lore.kernel.org/git/YwCtkwjWdJVHHZV0@coredump.intra.peff.net/
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.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 commit 29de20504e (Makefile: fix default regex settings on
Darwin, 2013-05-11) fixed t0070-fundamental.sh under Darwin (macOS) by
adopting Git's regex library. However, this library is compiled with
NO_MBSUPPORT, which causes git-grep to work incorrectly on multibyte
(e.g. UTF-8) files. Current macOS versions pass t0070-fundamental.sh
with the native macOS regex library, which also supports multibyte
characters.
Adjust the Makefile to use the native regex library, and call
setlocale(3) to set CTYPE according to the user's preference.
The setlocale call is required on all platforms, but in platforms
supporting gettext(3), setlocale was called as a side-effect of
initializing gettext. Therefore, move the CTYPE setlocale call from
gettext.c to common-main.c and the corresponding locale.h include
into git-compat-util.h.
Thanks to the global initialization of CTYPE setlocale, the test-tool
regex command now works correctly with supported multibyte regexes, and
is used to set the MB_REGEX test prerequisite by assessing a platform's
support for them.
Signed-off-by: Diomidis Spinellis <dds@aueb.gr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The "diagnose" feature to create a zip archive for diagnostic
material has been lifted from "scalar" and made into a feature of
"git bugreport".
* vd/scalar-generalize-diagnose:
scalar: update technical doc roadmap
scalar-diagnose: use 'git diagnose --mode=all'
builtin/bugreport.c: create '--diagnose' option
builtin/diagnose.c: add '--mode' option
builtin/diagnose.c: create 'git diagnose' builtin
diagnose.c: add option to configure archive contents
scalar-diagnose: move functionality to common location
scalar-diagnose: move 'get_disk_info()' to 'compat/'
scalar-diagnose: add directory to archiver more gently
scalar-diagnose: avoid 32-bit overflow of size_t
scalar-diagnose: use "$GIT_UNZIP" in test
Fix deadlocks between main Git process and subprocess spawned via
the pipe_command() API, that can kill "git add -p" that was
reimplemented in C recently.
* jk/pipe-command-nonblock:
pipe_command(): mark stdin descriptor as non-blocking
pipe_command(): handle ENOSPC when writing to a pipe
pipe_command(): avoid xwrite() for writing to pipe
git-compat-util: make MAX_IO_SIZE define globally available
nonblock: support Windows
compat: add function to enable nonblocking pipes
In the non-Windows version of this function, we never have any errors to
report, and thus the "report" parameter is unused. But we can't drop it,
because we have to maintain function call compatibility with the version
in compat/mingw.h, which does use this parameter.
Note that there's an extra level of indirection here; the common
function is actually is_path_owned_by_current_user, which is a macro
pointing to "by_current_uid" or "by_current_sid", depending on the
platform. So an alternative here is to eat the unused parameter in the
macro, since -Wunused-parameter doesn't complain about macros. But I
think the UNUSED() annotation is less obfuscated for somebody reading
the code later.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
