git/trace.c, branch v2.40.2

trace.c, git.c: remove unnecessary parameter to trace_repo_setup()

2023-02-21T20:06:32Z

trace_repo_setup() of trace.c is called with the argument 'prefix' from only one location, run_builtin of git.c, which sets 'prefix' to the return value of setup_git_directory() or setup_git_directory_gently() (a wrapper of the former). Now that "prefix" is in startup_info there is no need for the parameter of trace_repo_setup() because setup_git_directory() sets "startup_info->prefix" to the same value it returns. It would be less confusing to use "prefix" from startup_info instead of passing it as an argument. Signed-off-by: Idriss Fekir Signed-off-by: Junio C Hamano

C99: remove hardcoded-out !HAVE_VARIADIC_MACROS code

2022-02-22T03:14:19Z

Remove the "else" branches of the HAVE_VARIADIC_MACROS macro, which have been unconditionally omitted since 765dc168882 (git-compat-util: always enable variadic macros, 2021-01-28). Since were always omitted, anyone trying to use a compiler without variadic macro support to compile a git since version git v2.31.0 or later would have had a compilation error. 10 months across a few releases since then should have been enough time for anyone who cared to run into that and report the issue. In addition to that, for anyone unsetting HAVE_VARIADIC_MACROS we've been emitting extremely verbose warnings since at least ee4512ed481 (trace2: create new combined trace facility, 2019-02-22). That's because there is no such thing as a "region_enter_printf" or "region_leave_printf" format, so at least under GCC and Clang everything that includes trace.h (almost every file) emits a couple of warnings about that. There's a large benefit to being able to have a hard dependency rely on variadic macros, the code surrounding usage.c is hard to maintain if we need to write two implementations of everything, and by relying on "__FILE__" and "__LINE__" along with "__VA_ARGS__" we can in the future make error(), die() etc. log where they were called from. We've also recently merged d67fc4bf0ba (Merge branch 'bc/require-c99', 2021-12-10) which further cements our hard dependency on C99. So let's delete the fallback code, and update our CodingGuidelines to note that we depend on this. The added bullet-point starts with lower-case for consistency with other bullet-points in that section. The diff in "trace.h" is relatively hard to read, since we need to retain the existing API docs, which were comments on the code used if HAVE_VARIADIC_MACROS was not defined. Signed-off-by: Ævar Arnfjörð Bjarmason Signed-off-by: Junio C Hamano

http, imap-send: stop using CURLOPT_VERBOSE

2020-05-11T18:18:01Z

Whenever GIT_CURL_VERBOSE is set, teach Git to behave as if GIT_TRACE_CURL=1 and GIT_TRACE_CURL_NO_DATA=1 is set, instead of setting CURLOPT_VERBOSE. This is to prevent inadvertent revelation of sensitive data. In particular, GIT_CURL_VERBOSE redacts neither the "Authorization" header nor any cookies specified by GIT_REDACT_COOKIES. Unifying the tracing mechanism also has the future benefit that any improvements to the tracing mechanism will benefit both users of GIT_CURL_VERBOSE and GIT_TRACE_CURL, and we do not need to remember to implement any improvement twice. Signed-off-by: Jonathan Tan Signed-off-by: Junio C Hamano

packfile: drop release_pack_memory()

2019-08-13T19:21:33Z

Long ago, in 97bfeb34df (Release pack windows before reporting out of memory., 2006-12-24), we taught xmalloc() and friends to try unmapping pack windows when malloc() failed. It's unlikely that his helps a lot in practice, and it has some downsides. First, the downsides: 1. It makes xmalloc() not thread-safe. We've worked around this in pack-objects.c, which installs its own locking version of the try_to_free_routine(). But other threaded code doesn't. 2. It makes the system as a whole harder to reason about. Functions which allocate heap memory under the hood may have farther-reaching effects than expected. That might be worth the tradeoff if there's a benefit. But in practice, it seems unlikely. We're generally dealing with mmap'd files, so the OS is going to do a much better job at responding to memory pressure by dropping individual pages (the exception is systems with NO_MMAP, but even there the OS can probably respond just as well with swapping). So the only thing we're really freeing is address space. On 64-bit systems, we have plenty of that to go around. On 32-bit systems, it could possibly help. But around the same time we made two other changes: 77ccc5bbd1 (Introduce new config option for mmap limit., 2006-12-23) and 60bb8b1453 (Fully activate the sliding window pack access., 2006-12-23). Together that means that a 32-bit system should have no more than 256MB total of packed-git mmaps at one time, split between a few 32MB windows. It's unlikely we have any address space problems since then, but we don't have any data since the features were all added at the same time. Likewise, xmmap() will try to free memory. At first glance, it seems like we'd need this (when we try to mmap a new window, we might need to close an old one to save address space on a 32-bit system). But we're saved again by core.packedGitLimit: if we're going to exceed our 256MB limit, we'll close an existing window before we even call mmap(). So it seems unlikely that this feature is actually doing anything useful. And while we don't have reports of it harming anything (probably because it rarely if ever kicks in), it would be nice to simplify the system overall. This patch drops the whole try_to_free system from xmalloc(), as well as the manual pack memory release in xmmap(). Signed-off-by: Jeff King Signed-off-by: Junio C Hamano

trace.h: support nested performance tracing

2018-08-18T16:47:46Z

Performance measurements are listed right now as a flat list, which is fine when we measure big blocks. But when we start adding more and more measurements, some of them could be just part of a bigger measurement and a flat list gives a wrong impression that they are executed at the same level instead of nested. Add trace_performance_enter() and trace_performance_leave() to allow indent these nested measurements. For now it does not help much because the only nested thing is (lazy) name hash initialization (e.g. called in diff-index from "git status"). This will help more because I'm going to add some more tracing that's actually nested. Signed-off-by: Nguyễn Thái Ngọc Duy Signed-off-by: Junio C Hamano

trace.c: export trace_setup_key

2018-03-30T19:49:57Z

This is so that we can print traces based on this key outside trace.c. Signed-off-by: Nguyễn Thái Ngọc Duy Signed-off-by: Jeff King Signed-off-by: Junio C Hamano

trace.c: move strbuf_release() out of print_trace_line()

2018-01-16T20:16:54Z

The function is about printing a trace line, not releasing the buffer it receives too. Move strbuf_release() back outside. This makes it easier to see how strbuf is managed. Signed-off-by: Nguyễn Thái Ngọc Duy Signed-off-by: Junio C Hamano

trace: avoid unnecessary quoting

2018-01-16T20:16:54Z

Trace output which contains arbitrary strings (e.g., the arguments to commands which we are running) is always passed through sq_quote_buf(). That function always adds single-quotes, even if the output consists of vanilla characters. This can make the output a bit hard to read. Let's avoid the quoting if there are no characters which a shell would interpret. Trace output doesn't necessarily need to be shell-compatible, but: - the shell language is a good ballpark for what humans consider readable (well, humans versed in command line tools) - the run_command bits can be cut-and-pasted to a shell, and we'll keep that property - it covers any cases which would make the output visually ambiguous (e.g., embedded whitespace or quotes) Signed-off-by: Jeff King Signed-off-by: Nguyễn Thái Ngọc Duy Signed-off-by: Junio C Hamano

sq_quote_argv: drop maxlen parameter

2018-01-16T20:16:54Z

No caller passes anything but "0" for this parameter, which requests that the function ignore it completely. In fact, in all of history there was only one such caller, and it went away in 7f51f8bc2b (alias: use run_command api to execute aliases, 2011-01-07). Signed-off-by: Jeff King Signed-off-by: Nguyễn Thái Ngọc Duy Signed-off-by: Junio C Hamano

trace: improve performance while category is disabled

2017-12-06T17:43:02Z

Move just enough code from trace.c into trace.h header so all code necessary to determine that trace is disabled could be inlined to calling functions. Then perform the check if the trace key is enabled sooner in call chain. Signed-off-by: Gennady Kupava Signed-off-by: Junio C Hamano