From f706bca00a9645c01622d2e17687509dc305c6ed Mon Sep 17 00:00:00 2001 From: Jeff Hostetler Date: Mon, 14 Dec 2020 13:48:26 -0500 Subject: [PATCH 1/3] fsmonitor--daemon: man page and documentation Create a manual page describing the `git fsmonitor--daemon` feature. Update references to `core.fsmonitor`, `core.fsmonitorHookVersion` and pointers to `watchman` to mention the built-in FSMonitor. Signed-off-by: Jeff Hostetler --- Documentation/config/core.txt | 45 +++++++--- Documentation/git-fsmonitor--daemon.txt | 104 ++++++++++++++++++++++++ Documentation/git-update-index.txt | 4 +- Documentation/githooks.txt | 3 +- 4 files changed, 144 insertions(+), 12 deletions(-) create mode 100644 Documentation/git-fsmonitor--daemon.txt diff --git a/Documentation/config/core.txt b/Documentation/config/core.txt index c04f62a54a154c..d6e2f01966cba3 100644 --- a/Documentation/config/core.txt +++ b/Documentation/config/core.txt @@ -66,18 +66,43 @@ core.fsmonitor:: will identify all files that may have changed since the requested date/time. This information is used to speed up git by avoiding unnecessary processing of files that have not changed. - See the "fsmonitor-watchman" section of linkgit:githooks[5]. ++ +See the "fsmonitor-watchman" section of linkgit:githooks[5]. ++ +Note: FSMonitor hooks (and this config setting) are ignored if the +built-in FSMonitor is enabled (see `core.useBuiltinFSMonitor`). core.fsmonitorHookVersion:: - Sets the version of hook that is to be used when calling fsmonitor. - There are currently versions 1 and 2. When this is not set, - version 2 will be tried first and if it fails then version 1 - will be tried. Version 1 uses a timestamp as input to determine - which files have changes since that time but some monitors - like watchman have race conditions when used with a timestamp. - Version 2 uses an opaque string so that the monitor can return - something that can be used to determine what files have changed - without race conditions. + Sets the version of hook that is to be used when calling the + FSMonitor hook (as configured via `core.fsmonitor`). ++ +There are currently versions 1 and 2. When this is not set, +version 2 will be tried first and if it fails then version 1 +will be tried. Version 1 uses a timestamp as input to determine +which files have changes since that time but some monitors +like watchman have race conditions when used with a timestamp. +Version 2 uses an opaque string so that the monitor can return +something that can be used to determine what files have changed +without race conditions. ++ +Note: FSMonitor hooks (and this config setting) are ignored if the +built-in FSMonitor is enabled (see `core.useBuiltinFSMonitor`). + +core.useBuiltinFSMonitor:: + If set to true, enable the built-in filesystem event watcher (for + technical details, see linkgit:git-fsmonitor--daemon[1]). ++ +Like external (hook-based) FSMonitors, the built-in FSMonitor can speed up +Git commands that need to refresh the Git index (e.g. `git status`) in a +worktree with many files. The built-in FSMonitor facility eliminates the +need to install and maintain an external third-party monitoring tool. ++ +The built-in FSMonitor is currently available only on a limited set of +supported platforms. ++ +Note: if this config setting is set to `true`, any FSMonitor hook +configured via `core.fsmonitor` (and possibly `core.fsmonitorHookVersion`) +is ignored. core.trustctime:: If false, the ctime differences between the index and the diff --git a/Documentation/git-fsmonitor--daemon.txt b/Documentation/git-fsmonitor--daemon.txt new file mode 100644 index 00000000000000..b94f57c97fe472 --- /dev/null +++ b/Documentation/git-fsmonitor--daemon.txt @@ -0,0 +1,104 @@ +git-fsmonitor--daemon(1) +======================== + +NAME +---- +git-fsmonitor--daemon - Builtin file system monitor daemon + +SYNOPSIS +-------- +[verse] +'git fsmonitor--daemon' --start +'git fsmonitor--daemon' --run +'git fsmonitor--daemon' --stop +'git fsmonitor--daemon' --is-running +'git fsmonitor--daemon' --is-supported +'git fsmonitor--daemon' --query +'git fsmonitor--daemon' --query-index +'git fsmonitor--daemon' --flush + +DESCRIPTION +----------- + +Monitors files and directories in the working directory for changes using +platform-specific file system notification facilities. + +It communicates directly with commands like `git status` using the +link:technical/api-simple-ipc.html[simple IPC] interface instead of +the slower linkgit:githooks[5] interface. + +OPTIONS +------- + +--start:: + Starts the fsmonitor daemon in the background. + +--run:: + Runs the fsmonitor daemon in the foreground. + +--stop:: + Stops the fsmonitor daemon running for the current working + directory, if present. + +--is-running:: + Exits with zero status if the fsmonitor daemon is watching the + current working directory. + +--is-supported:: + Exits with zero status if the fsmonitor daemon feature is supported + on this platform. + +--query :: + Connects to the fsmonitor daemon (starting it if necessary) and + requests the list of changed files and directories since the + given token. + This is intended for testing purposes. + +--query-index:: + Read the current `` from the File System Monitor index + extension (if present) and use it to query the fsmonitor daemon. + This is intended for testing purposes. + +--flush:: + Force the fsmonitor daemon to flush its in-memory cache and + re-sync with the file system. + This is intended for testing purposes. + +REMARKS +------- +The fsmonitor daemon is a long running process that will watch a single +working directory. Commands, such as `git status`, should automatically +start it (if necessary) when `core.useBuiltinFSMonitor` is set to `true` +(see linkgit:git-config[1]). + +Configure the built-in FSMonitor via `core.useBuiltinFSMonitor` in each +working directory separately, or globally via `git config --global +core.useBuiltinFSMonitor true`. + +Tokens are opaque strings. They are used by the fsmonitor daemon to +mark a point in time and the associated internal state. Callers should +make no assumptions about the content of the token. In particular, +the should not assume that it is a timestamp. + +Query commands send a request-token to the daemon and it responds with +a summary of the changes that have occurred since that token was +created. The daemon also returns a response-token that the client can +use in a future query. + +For more information see the "File System Monitor" section in +linkgit:git-update-index[1]. + +CAVEATS +------- + +The fsmonitor daemon does not currently know about submodules and does +not know to filter out file system events that happen within a +submodule. If fsmonitor daemon is watching a super repo and a file is +modified within the working directory of a submodule, it will report +the change (as happening against the super repo). However, the client +should properly ignore these extra events, so performance may be affected +but it should not cause an incorrect result. + +GIT +--- +Part of the linkgit:git[1] suite diff --git a/Documentation/git-update-index.txt b/Documentation/git-update-index.txt index 2853f168d97685..8169aad7ee9fcd 100644 --- a/Documentation/git-update-index.txt +++ b/Documentation/git-update-index.txt @@ -498,7 +498,9 @@ FILE SYSTEM MONITOR This feature is intended to speed up git operations for repos that have large working directories. -It enables git to work together with a file system monitor (see the +It enables git to work together with a file system monitor (see +linkgit:git-fsmonitor--daemon[1] +and the "fsmonitor-watchman" section of linkgit:githooks[5]) that can inform it as to what files have been modified. This enables git to avoid having to lstat() every file to find modified files. diff --git a/Documentation/githooks.txt b/Documentation/githooks.txt index b51959ff9418fd..b7d5e926f7b042 100644 --- a/Documentation/githooks.txt +++ b/Documentation/githooks.txt @@ -593,7 +593,8 @@ fsmonitor-watchman This hook is invoked when the configuration option `core.fsmonitor` is set to `.git/hooks/fsmonitor-watchman` or `.git/hooks/fsmonitor-watchmanv2` -depending on the version of the hook to use. +depending on the version of the hook to use, unless overridden via +`core.useBuiltinFSMonitor` (see linkgit:git-config[1]). Version 1 takes two arguments, a version (1) and the time in elapsed nanoseconds since midnight, January 1, 1970. From 39c9ea3ab6a7807929b618148be5653b55996162 Mon Sep 17 00:00:00 2001 From: Johannes Schindelin Date: Fri, 5 Mar 2021 23:07:26 +0100 Subject: [PATCH 2/3] fsmonitor: mark the built-in FSMonitor as experimental Signed-off-by: Johannes Schindelin --- Documentation/config/core.txt | 8 +++++--- Documentation/git-fsmonitor--daemon.txt | 5 ++++- 2 files changed, 9 insertions(+), 4 deletions(-) diff --git a/Documentation/config/core.txt b/Documentation/config/core.txt index d6e2f01966cba3..bca1f6fb32330e 100644 --- a/Documentation/config/core.txt +++ b/Documentation/config/core.txt @@ -70,7 +70,8 @@ core.fsmonitor:: See the "fsmonitor-watchman" section of linkgit:githooks[5]. + Note: FSMonitor hooks (and this config setting) are ignored if the -built-in FSMonitor is enabled (see `core.useBuiltinFSMonitor`). +(experimental) built-in FSMonitor is enabled (see +`core.useBuiltinFSMonitor`). core.fsmonitorHookVersion:: Sets the version of hook that is to be used when calling the @@ -89,8 +90,9 @@ Note: FSMonitor hooks (and this config setting) are ignored if the built-in FSMonitor is enabled (see `core.useBuiltinFSMonitor`). core.useBuiltinFSMonitor:: - If set to true, enable the built-in filesystem event watcher (for - technical details, see linkgit:git-fsmonitor--daemon[1]). + (EXPERIMENTAL) If set to true, enable the built-in filesystem + event watcher (for technical details, see + linkgit:git-fsmonitor--daemon[1]). + Like external (hook-based) FSMonitors, the built-in FSMonitor can speed up Git commands that need to refresh the Git index (e.g. `git status`) in a diff --git a/Documentation/git-fsmonitor--daemon.txt b/Documentation/git-fsmonitor--daemon.txt index b94f57c97fe472..ec0012b3454d6c 100644 --- a/Documentation/git-fsmonitor--daemon.txt +++ b/Documentation/git-fsmonitor--daemon.txt @@ -3,7 +3,7 @@ git-fsmonitor--daemon(1) NAME ---- -git-fsmonitor--daemon - Builtin file system monitor daemon +git-fsmonitor--daemon - (EXPERIMENTAL) Builtin file system monitor daemon SYNOPSIS -------- @@ -20,6 +20,9 @@ SYNOPSIS DESCRIPTION ----------- +NOTE! This command is still only an experiment, subject to change dramatically +(or even to be abandoned). + Monitors files and directories in the working directory for changes using platform-specific file system notification facilities. From afcc1f17d66d7f6761334421769be53b5a0fd160 Mon Sep 17 00:00:00 2001 From: Johannes Schindelin Date: Fri, 5 Mar 2021 23:12:11 +0100 Subject: [PATCH 3/3] Enable the built-in FSMonitor as an experimental feature If `feature.experimental` and `feature.manyFiles` are set, we now start the built-in FSMonitor by default. Signed-off-by: Johannes Schindelin --- repo-settings.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/repo-settings.c b/repo-settings.c index bbcf71461ba22f..237dbfe61d6fbf 100644 --- a/repo-settings.c +++ b/repo-settings.c @@ -2,12 +2,13 @@ #include "config.h" #include "repository.h" #include "midx.h" +#include "fsmonitor-ipc.h" #define UPDATE_DEFAULT_BOOL(s,v) do { if (s == -1) { s = v; } } while(0) void prepare_repo_settings(struct repository *r) { - int value; + int value, feature_many_files = 0; char *strval; if (r->settings.initialized) @@ -62,6 +63,7 @@ void prepare_repo_settings(struct repository *r) r->settings.use_builtin_fsmonitor = 1; if (!repo_config_get_bool(r, "feature.manyfiles", &value) && value) { + feature_many_files = 1; UPDATE_DEFAULT_BOOL(r->settings.index_version, 4); UPDATE_DEFAULT_BOOL(r->settings.core_untracked_cache, UNTRACKED_CACHE_WRITE); } @@ -70,8 +72,12 @@ void prepare_repo_settings(struct repository *r) r->settings.fetch_write_commit_graph = value; UPDATE_DEFAULT_BOOL(r->settings.fetch_write_commit_graph, 0); - if (!repo_config_get_bool(r, "feature.experimental", &value) && value) + if (!repo_config_get_bool(r, "feature.experimental", &value) && value) { UPDATE_DEFAULT_BOOL(r->settings.fetch_negotiation_algorithm, FETCH_NEGOTIATION_SKIPPING); + if (feature_many_files && fsmonitor_ipc__is_supported()) + UPDATE_DEFAULT_BOOL(r->settings.use_builtin_fsmonitor, + 1); + } /* Hack for test programs like test-dump-untracked-cache */ if (ignore_untracked_cache_config)