diff options
Diffstat (limited to 'include/ruby/thread.h')
| -rw-r--r-- | include/ruby/thread.h | 291 |
1 files changed, 287 insertions, 4 deletions
diff --git a/include/ruby/thread.h b/include/ruby/thread.h index b05537badb..337f477fd0 100644 --- a/include/ruby/thread.h +++ b/include/ruby/thread.h @@ -10,33 +10,316 @@ * modify this file, provided that the conditions mentioned in the * file COPYING are met. Consult the file for details. */ -#include "ruby/intern.h" +#include "ruby/internal/attr/nonnull.h" +#include "ruby/internal/intern/thread.h" /* rb_unblock_function_t */ #include "ruby/internal/dllexport.h" -/* flags for rb_nogvl */ +/** + * @name Flags for rb_nogvl() + * + * @{ + */ + +/** + * Passing this flag to rb_nogvl() prevents it from checking interrupts. + * Interrupts can impact your program negatively. For instance consider + * following callback function: + * + * ```CXX + * static inline int fd; // set elsewhere. + * static inline auto callback(auto buf) { + * auto tmp = ruby_xmalloc(BUFSIZ); + * auto ret = ruby_xmalloc(sizeof(ssize_t)); // (a) + * auto n = read(fd, tmp, BUFSIZ); // (b) + * memcpy(buf, tmp, n); // (c) + * memcpy(ret, n, sizeof(n)); + * ruby_xfree(tmp); + * return ret; + * } + * ``` + * + * Here, if it gets interrupted at (a) or (b), `read(2)` is cancelled and this + * function leaks memory (which is not a good thing of course, but...). But if + * it gets interrupted at (c), where `read(2)` is already done, interruption is + * way more catastrophic because what was read gets lost. To reroute this kind + * of problem you should set this flag. And check interrupts elsewhere at your + * own risk. + */ #define RB_NOGVL_INTR_FAIL (0x1) + +/** + * Passing this flag to rb_nogvl() indicates that the passed UBF is + * async-signal-safe. An UBF could be async safe, and that makes things + * simpler. However async unsafe UBFs are just okay. If unsure, you can + * safely leave it unspecified. + * + * @internal + * + * This makes sense only in case of POSIX threads. + */ #define RB_NOGVL_UBF_ASYNC_SAFE (0x2) +/** @} */ + RBIMPL_SYMBOL_EXPORT_BEGIN() +RBIMPL_ATTR_NONNULL((1)) +/** + * (Re-)acquires the GVL. This manoeuvre makes it possible for an out-of-GVL + * routine to one-shot call a ruby method. + * + * What this function does: + * + * 1. Blocks until it acquires the GVL. + * 2. Calls the passed function. + * 3. Releases the GVL. + * 4. Returns what was returned form the passed function. + * + * @param[in] func What to call with GVL. + * @param[in,out] data1 Passed as-is to `func`. + * @return What was returned from `func`. + * @warning `func` must not return a Ruby object. If it did such return + * value would escape from GC's scope; would not be marked. + * @warning Global escapes from this function just yield whatever fatal + * undefined behaviours. You must make sure that `func` does + * not raise, by properly rescuing everything using + * e.g. rb_protect(). + * @warning You cannot convert a non-Ruby thread into a Ruby thread + * using this API. This function makes sense only from inside + * of a rb_thread_call_without_gvl()'s callback. + */ void *rb_thread_call_with_gvl(void *(*func)(void *), void *data1); +RBIMPL_ATTR_NONNULL((1)) +/** + * Allows the passed function to run in parallel with other Ruby threads. + * + * What this function does: + * + * 1. Checks (and handles) pending interrupts. + * 2. Releases the GVL. (Others can run here in parallel...) + * 3. Calls the passed function. + * 4. Blocks until it re-acquires the GVL. + * 5. Checks interrupts that happened between 2 to 4. + * + * In case other threads interfaced with this thread using rb_thread_kill() + * etc., the passed UBF is additionally called. See ::rb_unblock_function_t + * for details. + * + * Unlike rb_thread_call_without_gvl2() this function also reacts to signals + * etc. + * + * @param[in] func A function to call without GVL. + * @param[in,out] data1 Passed as-is to `func`. + * @param[in] ubf An UBF to cancel `func`. + * @param[in,out] data2 Passed as-is to `ubf`. + * @return What `func` returned, or 0 in case `ubf` cancelled `func`. + * @warning You cannot use most of Ruby C APIs like calling methods or + * raising exceptions from any of the functions passed to it. + * If that is dead necessary use rb_thread_call_with_gvl() to + * re-acquire the GVL. + * @warning In short, this API is difficult. @ko1 recommends you to use + * other ways if any. We lack experiences to use this API. If + * you find any corner cases etc., please report it to the + * devs. + * @warning Releasing and re-acquiring the GVL are expensive operations. + * For a short-running `func`, it might be faster to just call + * `func` with blocking everything else. Be sure to benchmark + * your code to see if it is actually worth releasing the GVL. + */ void *rb_thread_call_without_gvl(void *(*func)(void *), void *data1, - rb_unblock_function_t *ubf, void *data2); + rb_unblock_function_t *ubf, void *data2); + +RBIMPL_ATTR_NONNULL((1)) +/** + * Identical to rb_thread_call_without_gvl(), except it does not interface with + * signals etc. As described in #RB_NOGVL_INTR_FAIL, interrupts can hurt you. + * In case this function detects an interrupt, it returns immediately. You can + * record progress of your callback and check it after returning from this + * function. + * + * What this function does: + * + * 1. Checks for pending interrupts and if any, just returns. + * 2. Releases the GVL. (Others can run here in parallel...) + * 3. Calls the passed function. + * 4. Blocks until it re-acquires the GVL. + * + * @param[in] func A function to call without GVL. + * @param[in,out] data1 Passed as-is to `func`. + * @param[in] ubf An UBF to cancel `func`. + * @param[in,out] data2 Passed as-is to `ubf`. + * @return What `func` returned, or 0 in case `func` did not return. + */ void *rb_thread_call_without_gvl2(void *(*func)(void *), void *data1, - rb_unblock_function_t *ubf, void *data2); + rb_unblock_function_t *ubf, void *data2); /* * XXX: unstable/unapproved - out-of-tree code should NOT not depend * on this until it hits Ruby 2.6.1 */ + +RBIMPL_ATTR_NONNULL((1)) +/** + * Identical to rb_thread_call_without_gvl(), except it additionally takes + * "flags" that change the behaviour. + * + * @param[in] func A function to call without GVL. + * @param[in,out] data1 Passed as-is to `func`. + * @param[in] ubf An UBF to cancel `func`. + * @param[in,out] data2 Passed as-is to `ubf`. + * @param[in] flags Flags. + * @return What `func` returned, or 0 in case `func` did not return. + */ void *rb_nogvl(void *(*func)(void *), void *data1, rb_unblock_function_t *ubf, void *data2, int flags); +/** + * @private + * + * @deprecated This macro once was a thing in the old days, but makes no sense + * any longer today. Exists here for backwards compatibility + * only. You can safely forget about it. + */ #define RUBY_CALL_WO_GVL_FLAG_SKIP_CHECK_INTS_AFTER 0x01 + +/** + * @private + * @deprecated It seems even in the old days it made no sense...? + */ #define RUBY_CALL_WO_GVL_FLAG_SKIP_CHECK_INTS_ +/** + * Declare the current Ruby thread should acquire a dedicated + * native thread on M:N thread scheduler. + * + * If a C extension (or a library which the extension relies on) should + * keep to run on a native thread (e.g. using thread-local-storage), + * this function allocates a dedicated native thread for the thread. + * + * @return `false` if the thread already running on a dedicated native + * thread. Otherwise `true`. + */ +bool rb_thread_lock_native_thread(void); + +/** + * Triggered when a new thread is started. + * + * @note The callback will be called *without* the GVL held. + */ +#define RUBY_INTERNAL_THREAD_EVENT_STARTED 1 << 0 + +/** +* Triggered when a thread attempt to acquire the GVL. +* +* @note The callback will be called *without* the GVL held. +*/ +#define RUBY_INTERNAL_THREAD_EVENT_READY 1 << 1 /** acquiring GVL */ + +/** + * Triggered when a thread successfully acquired the GVL. + * + * @note The callback will be called *with* the GVL held. + */ +#define RUBY_INTERNAL_THREAD_EVENT_RESUMED 1 << 2 /** acquired GVL */ + +/** + * Triggered when a thread released the GVL. + * + * @note The callback will be called *without* the GVL held. + */ +#define RUBY_INTERNAL_THREAD_EVENT_SUSPENDED 1 << 3 /** released GVL */ + +/** + * Triggered when a thread exits. + * + * @note The callback will be called *without* the GVL held. + */ +#define RUBY_INTERNAL_THREAD_EVENT_EXITED 1 << 4 /** thread terminated */ + +#define RUBY_INTERNAL_THREAD_EVENT_MASK 0xff /** All Thread events */ + +typedef struct rb_internal_thread_event_data { + VALUE thread; +} rb_internal_thread_event_data_t; + +typedef void (*rb_internal_thread_event_callback)(rb_event_flag_t event, + const rb_internal_thread_event_data_t *event_data, + void *user_data); +typedef struct rb_internal_thread_event_hook rb_internal_thread_event_hook_t; + +/** + * Registers a thread event hook function. + * + * @param[in] func A callback. + * @param[in] events A set of events that `func` should run. + * @param[in] data Passed as-is to `func`. + * @return An opaque pointer to the hook, to unregister it later. + * @note This functionality is a noop on Windows and WebAssembly. + * @note The callback will be called without the GVL held, except for the + * RESUMED event. + * @note Callbacks are not guaranteed to be executed on the native threads + * that corresponds to the Ruby thread. To identify which Ruby thread + * the event refers to, you must use `event_data->thread`. + * @warning This function MUST not be called from a thread event callback. + */ +rb_internal_thread_event_hook_t *rb_internal_thread_add_event_hook( + rb_internal_thread_event_callback func, rb_event_flag_t events, + void *data); + + +/** + * Unregister the passed hook. + * + * @param[in] hook. The hook to unregister. + * @return Whether the hook was found and unregistered. + * @note This functionality is a noop on Windows and WebAssembly. + * @warning This function MUST not be called from a thread event callback. +*/ +bool rb_internal_thread_remove_event_hook( + rb_internal_thread_event_hook_t * hook); + + +typedef int rb_internal_thread_specific_key_t; +#define RB_INTERNAL_THREAD_SPECIFIC_KEY_MAX 8 +/** + * Create a key to store thread specific data. + * + * These APIs are designed for tools using + * rb_internal_thread_event_hook APIs. + * + * Note that only `RB_INTERNAL_THREAD_SPECIFIC_KEY_MAX` keys + * can be created. raises `ThreadError` if exceeded. + * + * Usage: + * // at initialize time: + * int tool_key; // gvar + * Init_tool() { + * tool_key = rb_internal_thread_specific_key_create(); + * } + * + * // at any timing: + * rb_internal_thread_specific_set(thread, tool_key, per_thread_data); + * ... + * per_thread_data = rb_internal_thread_specific_get(thread, tool_key); + */ +rb_internal_thread_specific_key_t rb_internal_thread_specific_key_create(void); + +/** + * Get thread and tool specific data. + * + * This function is async signal safe and thread safe. + */ +void *rb_internal_thread_specific_get(VALUE thread_val, rb_internal_thread_specific_key_t key); + +/** + * Set thread and tool specific data. + * + * This function is async signal safe and thread safe. + */ +void rb_internal_thread_specific_set(VALUE thread_val, rb_internal_thread_specific_key_t key, void *data); + RBIMPL_SYMBOL_EXPORT_END() #endif /* RUBY_THREAD_H */ |