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cont.c
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cont.c
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/**********************************************************************
cont.c -
$Author$
created at: Thu May 23 09:03:43 2007
Copyright (C) 2007 Koichi Sasada
**********************************************************************/
#include "ruby/internal/config.h"
#ifndef _WIN32
#include <unistd.h>
#include <sys/mman.h>
#endif
// On Solaris, madvise() is NOT declared for SUS (XPG4v2) or later,
// but MADV_* macros are defined when __EXTENSIONS__ is defined.
#ifdef NEED_MADVICE_PROTOTYPE_USING_CADDR_T
#include <sys/types.h>
extern int madvise(caddr_t, size_t, int);
#endif
#include COROUTINE_H
#include "eval_intern.h"
#include "internal.h"
#include "internal/cont.h"
#include "internal/thread.h"
#include "internal/error.h"
#include "internal/gc.h"
#include "internal/proc.h"
#include "internal/sanitizers.h"
#include "internal/warnings.h"
#include "ruby/fiber/scheduler.h"
#include "rjit.h"
#include "yjit.h"
#include "vm_core.h"
#include "vm_sync.h"
#include "id_table.h"
#include "ractor_core.h"
static const int DEBUG = 0;
#define RB_PAGE_SIZE (pagesize)
#define RB_PAGE_MASK (~(RB_PAGE_SIZE - 1))
static long pagesize;
static const rb_data_type_t cont_data_type, fiber_data_type;
static VALUE rb_cContinuation;
static VALUE rb_cFiber;
static VALUE rb_eFiberError;
#ifdef RB_EXPERIMENTAL_FIBER_POOL
static VALUE rb_cFiberPool;
#endif
#define CAPTURE_JUST_VALID_VM_STACK 1
// Defined in `coroutine/$arch/Context.h`:
#ifdef COROUTINE_LIMITED_ADDRESS_SPACE
#define FIBER_POOL_ALLOCATION_FREE
#define FIBER_POOL_INITIAL_SIZE 8
#define FIBER_POOL_ALLOCATION_MAXIMUM_SIZE 32
#else
#define FIBER_POOL_INITIAL_SIZE 32
#define FIBER_POOL_ALLOCATION_MAXIMUM_SIZE 1024
#endif
#ifdef RB_EXPERIMENTAL_FIBER_POOL
#define FIBER_POOL_ALLOCATION_FREE
#endif
enum context_type {
CONTINUATION_CONTEXT = 0,
FIBER_CONTEXT = 1
};
struct cont_saved_vm_stack {
VALUE *ptr;
#ifdef CAPTURE_JUST_VALID_VM_STACK
size_t slen; /* length of stack (head of ec->vm_stack) */
size_t clen; /* length of control frames (tail of ec->vm_stack) */
#endif
};
struct fiber_pool;
// Represents a single stack.
struct fiber_pool_stack {
// A pointer to the memory allocation (lowest address) for the stack.
void * base;
// The current stack pointer, taking into account the direction of the stack.
void * current;
// The size of the stack excluding any guard pages.
size_t size;
// The available stack capacity w.r.t. the current stack offset.
size_t available;
// The pool this stack should be allocated from.
struct fiber_pool * pool;
// If the stack is allocated, the allocation it came from.
struct fiber_pool_allocation * allocation;
};
// A linked list of vacant (unused) stacks.
// This structure is stored in the first page of a stack if it is not in use.
// @sa fiber_pool_vacancy_pointer
struct fiber_pool_vacancy {
// Details about the vacant stack:
struct fiber_pool_stack stack;
// The vacancy linked list.
#ifdef FIBER_POOL_ALLOCATION_FREE
struct fiber_pool_vacancy * previous;
#endif
struct fiber_pool_vacancy * next;
};
// Manages singly linked list of mapped regions of memory which contains 1 more more stack:
//
// base = +-------------------------------+-----------------------+ +
// |VM Stack |VM Stack | | |
// | | | | |
// | | | | |
// +-------------------------------+ | |
// |Machine Stack |Machine Stack | | |
// | | | | |
// | | | | |
// | | | . . . . | | size
// | | | | |
// | | | | |
// | | | | |
// | | | | |
// | | | | |
// +-------------------------------+ | |
// |Guard Page |Guard Page | | |
// +-------------------------------+-----------------------+ v
//
// +------------------------------------------------------->
//
// count
//
struct fiber_pool_allocation {
// A pointer to the memory mapped region.
void * base;
// The size of the individual stacks.
size_t size;
// The stride of individual stacks (including any guard pages or other accounting details).
size_t stride;
// The number of stacks that were allocated.
size_t count;
#ifdef FIBER_POOL_ALLOCATION_FREE
// The number of stacks used in this allocation.
size_t used;
#endif
struct fiber_pool * pool;
// The allocation linked list.
#ifdef FIBER_POOL_ALLOCATION_FREE
struct fiber_pool_allocation * previous;
#endif
struct fiber_pool_allocation * next;
};
// A fiber pool manages vacant stacks to reduce the overhead of creating fibers.
struct fiber_pool {
// A singly-linked list of allocations which contain 1 or more stacks each.
struct fiber_pool_allocation * allocations;
// Free list that provides O(1) stack "allocation".
struct fiber_pool_vacancy * vacancies;
// The size of the stack allocations (excluding any guard page).
size_t size;
// The total number of stacks that have been allocated in this pool.
size_t count;
// The initial number of stacks to allocate.
size_t initial_count;
// Whether to madvise(free) the stack or not.
// If this value is set to 1, the stack will be madvise(free)ed
// (or equivalent), where possible, when it is returned to the pool.
int free_stacks;
// The number of stacks that have been used in this pool.
size_t used;
// The amount to allocate for the vm_stack.
size_t vm_stack_size;
};
// Continuation contexts used by JITs
struct rb_jit_cont {
rb_execution_context_t *ec; // continuation ec
struct rb_jit_cont *prev, *next; // used to form lists
};
// Doubly linked list for enumerating all on-stack ISEQs.
static struct rb_jit_cont *first_jit_cont;
typedef struct rb_context_struct {
enum context_type type;
int argc;
int kw_splat;
VALUE self;
VALUE value;
struct cont_saved_vm_stack saved_vm_stack;
struct {
VALUE *stack;
VALUE *stack_src;
size_t stack_size;
} machine;
rb_execution_context_t saved_ec;
rb_jmpbuf_t jmpbuf;
struct rb_jit_cont *jit_cont; // Continuation contexts for JITs
} rb_context_t;
/*
* Fiber status:
* [Fiber.new] ------> FIBER_CREATED ----> [Fiber#kill] --> |
* | [Fiber#resume] |
* v |
* +--> FIBER_RESUMED ----> [return] ------> |
* [Fiber#resume] | | [Fiber.yield/transfer] |
* [Fiber#transfer] | v |
* +--- FIBER_SUSPENDED --> [Fiber#kill] --> |
* |
* |
* FIBER_TERMINATED <-------------------+
*/
enum fiber_status {
FIBER_CREATED,
FIBER_RESUMED,
FIBER_SUSPENDED,
FIBER_TERMINATED
};
#define FIBER_CREATED_P(fiber) ((fiber)->status == FIBER_CREATED)
#define FIBER_RESUMED_P(fiber) ((fiber)->status == FIBER_RESUMED)
#define FIBER_SUSPENDED_P(fiber) ((fiber)->status == FIBER_SUSPENDED)
#define FIBER_TERMINATED_P(fiber) ((fiber)->status == FIBER_TERMINATED)
#define FIBER_RUNNABLE_P(fiber) (FIBER_CREATED_P(fiber) || FIBER_SUSPENDED_P(fiber))
struct rb_fiber_struct {
rb_context_t cont;
VALUE first_proc;
struct rb_fiber_struct *prev;
struct rb_fiber_struct *resuming_fiber;
BITFIELD(enum fiber_status, status, 2);
/* Whether the fiber is allowed to implicitly yield. */
unsigned int yielding : 1;
unsigned int blocking : 1;
unsigned int killed : 1;
struct coroutine_context context;
struct fiber_pool_stack stack;
};
static struct fiber_pool shared_fiber_pool = {NULL, NULL, 0, 0, 0, 0};
void
rb_free_shared_fiber_pool(void)
{
struct fiber_pool_allocation *allocations = shared_fiber_pool.allocations;
while (allocations) {
struct fiber_pool_allocation *next = allocations->next;
xfree(allocations);
allocations = next;
}
}
static ID fiber_initialize_keywords[3] = {0};
/*
* FreeBSD require a first (i.e. addr) argument of mmap(2) is not NULL
* if MAP_STACK is passed.
* https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=158755
*/
#if defined(MAP_STACK) && !defined(__FreeBSD__) && !defined(__FreeBSD_kernel__)
#define FIBER_STACK_FLAGS (MAP_PRIVATE | MAP_ANON | MAP_STACK)
#else
#define FIBER_STACK_FLAGS (MAP_PRIVATE | MAP_ANON)
#endif
#define ERRNOMSG strerror(errno)
// Locates the stack vacancy details for the given stack.
inline static struct fiber_pool_vacancy *
fiber_pool_vacancy_pointer(void * base, size_t size)
{
STACK_GROW_DIR_DETECTION;
return (struct fiber_pool_vacancy *)(
(char*)base + STACK_DIR_UPPER(0, size - RB_PAGE_SIZE)
);
}
#if defined(COROUTINE_SANITIZE_ADDRESS)
// Compute the base pointer for a vacant stack, for the area which can be poisoned.
inline static void *
fiber_pool_stack_poison_base(struct fiber_pool_stack * stack)
{
STACK_GROW_DIR_DETECTION;
return (char*)stack->base + STACK_DIR_UPPER(RB_PAGE_SIZE, 0);
}
// Compute the size of the vacant stack, for the area that can be poisoned.
inline static size_t
fiber_pool_stack_poison_size(struct fiber_pool_stack * stack)
{
return stack->size - RB_PAGE_SIZE;
}
#endif
// Reset the current stack pointer and available size of the given stack.
inline static void
fiber_pool_stack_reset(struct fiber_pool_stack * stack)
{
STACK_GROW_DIR_DETECTION;
stack->current = (char*)stack->base + STACK_DIR_UPPER(0, stack->size);
stack->available = stack->size;
}
// A pointer to the base of the current unused portion of the stack.
inline static void *
fiber_pool_stack_base(struct fiber_pool_stack * stack)
{
STACK_GROW_DIR_DETECTION;
VM_ASSERT(stack->current);
return STACK_DIR_UPPER(stack->current, (char*)stack->current - stack->available);
}
// Allocate some memory from the stack. Used to allocate vm_stack inline with machine stack.
// @sa fiber_initialize_coroutine
inline static void *
fiber_pool_stack_alloca(struct fiber_pool_stack * stack, size_t offset)
{
STACK_GROW_DIR_DETECTION;
if (DEBUG) fprintf(stderr, "fiber_pool_stack_alloca(%p): %"PRIuSIZE"/%"PRIuSIZE"\n", (void*)stack, offset, stack->available);
VM_ASSERT(stack->available >= offset);
// The pointer to the memory being allocated:
void * pointer = STACK_DIR_UPPER(stack->current, (char*)stack->current - offset);
// Move the stack pointer:
stack->current = STACK_DIR_UPPER((char*)stack->current + offset, (char*)stack->current - offset);
stack->available -= offset;
return pointer;
}
// Reset the current stack pointer and available size of the given stack.
inline static void
fiber_pool_vacancy_reset(struct fiber_pool_vacancy * vacancy)
{
fiber_pool_stack_reset(&vacancy->stack);
// Consume one page of the stack because it's used for the vacancy list:
fiber_pool_stack_alloca(&vacancy->stack, RB_PAGE_SIZE);
}
inline static struct fiber_pool_vacancy *
fiber_pool_vacancy_push(struct fiber_pool_vacancy * vacancy, struct fiber_pool_vacancy * head)
{
vacancy->next = head;
#ifdef FIBER_POOL_ALLOCATION_FREE
if (head) {
head->previous = vacancy;
vacancy->previous = NULL;
}
#endif
return vacancy;
}
#ifdef FIBER_POOL_ALLOCATION_FREE
static void
fiber_pool_vacancy_remove(struct fiber_pool_vacancy * vacancy)
{
if (vacancy->next) {
vacancy->next->previous = vacancy->previous;
}
if (vacancy->previous) {
vacancy->previous->next = vacancy->next;
}
else {
// It's the head of the list:
vacancy->stack.pool->vacancies = vacancy->next;
}
}
inline static struct fiber_pool_vacancy *
fiber_pool_vacancy_pop(struct fiber_pool * pool)
{
struct fiber_pool_vacancy * vacancy = pool->vacancies;
if (vacancy) {
fiber_pool_vacancy_remove(vacancy);
}
return vacancy;
}
#else
inline static struct fiber_pool_vacancy *
fiber_pool_vacancy_pop(struct fiber_pool * pool)
{
struct fiber_pool_vacancy * vacancy = pool->vacancies;
if (vacancy) {
pool->vacancies = vacancy->next;
}
return vacancy;
}
#endif
// Initialize the vacant stack. The [base, size] allocation should not include the guard page.
// @param base The pointer to the lowest address of the allocated memory.
// @param size The size of the allocated memory.
inline static struct fiber_pool_vacancy *
fiber_pool_vacancy_initialize(struct fiber_pool * fiber_pool, struct fiber_pool_vacancy * vacancies, void * base, size_t size)
{
struct fiber_pool_vacancy * vacancy = fiber_pool_vacancy_pointer(base, size);
vacancy->stack.base = base;
vacancy->stack.size = size;
fiber_pool_vacancy_reset(vacancy);
vacancy->stack.pool = fiber_pool;
return fiber_pool_vacancy_push(vacancy, vacancies);
}
// Allocate a maximum of count stacks, size given by stride.
// @param count the number of stacks to allocate / were allocated.
// @param stride the size of the individual stacks.
// @return [void *] the allocated memory or NULL if allocation failed.
inline static void *
fiber_pool_allocate_memory(size_t * count, size_t stride)
{
// We use a divide-by-2 strategy to try and allocate memory. We are trying
// to allocate `count` stacks. In normal situation, this won't fail. But
// if we ran out of address space, or we are allocating more memory than
// the system would allow (e.g. overcommit * physical memory + swap), we
// divide count by two and try again. This condition should only be
// encountered in edge cases, but we handle it here gracefully.
while (*count > 1) {
#if defined(_WIN32)
void * base = VirtualAlloc(0, (*count)*stride, MEM_COMMIT, PAGE_READWRITE);
if (!base) {
*count = (*count) >> 1;
}
else {
return base;
}
#else
errno = 0;
size_t mmap_size = (*count)*stride;
void * base = mmap(NULL, mmap_size, PROT_READ | PROT_WRITE, FIBER_STACK_FLAGS, -1, 0);
if (base == MAP_FAILED) {
// If the allocation fails, count = count / 2, and try again.
*count = (*count) >> 1;
}
else {
ruby_annotate_mmap(base, mmap_size, "Ruby:fiber_pool_allocate_memory");
#if defined(MADV_FREE_REUSE)
// On Mac MADV_FREE_REUSE is necessary for the task_info api
// to keep the accounting accurate as possible when a page is marked as reusable
// it can possibly not occurring at first call thus re-iterating if necessary.
while (madvise(base, mmap_size, MADV_FREE_REUSE) == -1 && errno == EAGAIN);
#endif
return base;
}
#endif
}
return NULL;
}
// Given an existing fiber pool, expand it by the specified number of stacks.
// @param count the maximum number of stacks to allocate.
// @return the allocated fiber pool.
// @sa fiber_pool_allocation_free
static struct fiber_pool_allocation *
fiber_pool_expand(struct fiber_pool * fiber_pool, size_t count)
{
STACK_GROW_DIR_DETECTION;
size_t size = fiber_pool->size;
size_t stride = size + RB_PAGE_SIZE;
// Allocate the memory required for the stacks:
void * base = fiber_pool_allocate_memory(&count, stride);
if (base == NULL) {
rb_raise(rb_eFiberError, "can't alloc machine stack to fiber (%"PRIuSIZE" x %"PRIuSIZE" bytes): %s", count, size, ERRNOMSG);
}
struct fiber_pool_vacancy * vacancies = fiber_pool->vacancies;
struct fiber_pool_allocation * allocation = RB_ALLOC(struct fiber_pool_allocation);
// Initialize fiber pool allocation:
allocation->base = base;
allocation->size = size;
allocation->stride = stride;
allocation->count = count;
#ifdef FIBER_POOL_ALLOCATION_FREE
allocation->used = 0;
#endif
allocation->pool = fiber_pool;
if (DEBUG) {
fprintf(stderr, "fiber_pool_expand(%"PRIuSIZE"): %p, %"PRIuSIZE"/%"PRIuSIZE" x [%"PRIuSIZE":%"PRIuSIZE"]\n",
count, (void*)fiber_pool, fiber_pool->used, fiber_pool->count, size, fiber_pool->vm_stack_size);
}
// Iterate over all stacks, initializing the vacancy list:
for (size_t i = 0; i < count; i += 1) {
void * base = (char*)allocation->base + (stride * i);
void * page = (char*)base + STACK_DIR_UPPER(size, 0);
#if defined(_WIN32)
DWORD old_protect;
if (!VirtualProtect(page, RB_PAGE_SIZE, PAGE_READWRITE | PAGE_GUARD, &old_protect)) {
VirtualFree(allocation->base, 0, MEM_RELEASE);
rb_raise(rb_eFiberError, "can't set a guard page: %s", ERRNOMSG);
}
#else
if (mprotect(page, RB_PAGE_SIZE, PROT_NONE) < 0) {
munmap(allocation->base, count*stride);
rb_raise(rb_eFiberError, "can't set a guard page: %s", ERRNOMSG);
}
#endif
vacancies = fiber_pool_vacancy_initialize(
fiber_pool, vacancies,
(char*)base + STACK_DIR_UPPER(0, RB_PAGE_SIZE),
size
);
#ifdef FIBER_POOL_ALLOCATION_FREE
vacancies->stack.allocation = allocation;
#endif
}
// Insert the allocation into the head of the pool:
allocation->next = fiber_pool->allocations;
#ifdef FIBER_POOL_ALLOCATION_FREE
if (allocation->next) {
allocation->next->previous = allocation;
}
allocation->previous = NULL;
#endif
fiber_pool->allocations = allocation;
fiber_pool->vacancies = vacancies;
fiber_pool->count += count;
return allocation;
}
// Initialize the specified fiber pool with the given number of stacks.
// @param vm_stack_size The size of the vm stack to allocate.
static void
fiber_pool_initialize(struct fiber_pool * fiber_pool, size_t size, size_t count, size_t vm_stack_size)
{
VM_ASSERT(vm_stack_size < size);
fiber_pool->allocations = NULL;
fiber_pool->vacancies = NULL;
fiber_pool->size = ((size / RB_PAGE_SIZE) + 1) * RB_PAGE_SIZE;
fiber_pool->count = 0;
fiber_pool->initial_count = count;
fiber_pool->free_stacks = 1;
fiber_pool->used = 0;
fiber_pool->vm_stack_size = vm_stack_size;
fiber_pool_expand(fiber_pool, count);
}
#ifdef FIBER_POOL_ALLOCATION_FREE
// Free the list of fiber pool allocations.
static void
fiber_pool_allocation_free(struct fiber_pool_allocation * allocation)
{
STACK_GROW_DIR_DETECTION;
VM_ASSERT(allocation->used == 0);
if (DEBUG) fprintf(stderr, "fiber_pool_allocation_free: %p base=%p count=%"PRIuSIZE"\n", (void*)allocation, allocation->base, allocation->count);
size_t i;
for (i = 0; i < allocation->count; i += 1) {
void * base = (char*)allocation->base + (allocation->stride * i) + STACK_DIR_UPPER(0, RB_PAGE_SIZE);
struct fiber_pool_vacancy * vacancy = fiber_pool_vacancy_pointer(base, allocation->size);
// Pop the vacant stack off the free list:
fiber_pool_vacancy_remove(vacancy);
}
#ifdef _WIN32
VirtualFree(allocation->base, 0, MEM_RELEASE);
#else
munmap(allocation->base, allocation->stride * allocation->count);
#endif
if (allocation->previous) {
allocation->previous->next = allocation->next;
}
else {
// We are the head of the list, so update the pool:
allocation->pool->allocations = allocation->next;
}
if (allocation->next) {
allocation->next->previous = allocation->previous;
}
allocation->pool->count -= allocation->count;
ruby_xfree(allocation);
}
#endif
// Acquire a stack from the given fiber pool. If none are available, allocate more.
static struct fiber_pool_stack
fiber_pool_stack_acquire(struct fiber_pool * fiber_pool)
{
struct fiber_pool_vacancy * vacancy = fiber_pool_vacancy_pop(fiber_pool);
if (DEBUG) fprintf(stderr, "fiber_pool_stack_acquire: %p used=%"PRIuSIZE"\n", (void*)fiber_pool->vacancies, fiber_pool->used);
if (!vacancy) {
const size_t maximum = FIBER_POOL_ALLOCATION_MAXIMUM_SIZE;
const size_t minimum = fiber_pool->initial_count;
size_t count = fiber_pool->count;
if (count > maximum) count = maximum;
if (count < minimum) count = minimum;
fiber_pool_expand(fiber_pool, count);
// The free list should now contain some stacks:
VM_ASSERT(fiber_pool->vacancies);
vacancy = fiber_pool_vacancy_pop(fiber_pool);
}
VM_ASSERT(vacancy);
VM_ASSERT(vacancy->stack.base);
#if defined(COROUTINE_SANITIZE_ADDRESS)
__asan_unpoison_memory_region(fiber_pool_stack_poison_base(&vacancy->stack), fiber_pool_stack_poison_size(&vacancy->stack));
#endif
// Take the top item from the free list:
fiber_pool->used += 1;
#ifdef FIBER_POOL_ALLOCATION_FREE
vacancy->stack.allocation->used += 1;
#endif
fiber_pool_stack_reset(&vacancy->stack);
return vacancy->stack;
}
// We advise the operating system that the stack memory pages are no longer being used.
// This introduce some performance overhead but allows system to relaim memory when there is pressure.
static inline void
fiber_pool_stack_free(struct fiber_pool_stack * stack)
{
void * base = fiber_pool_stack_base(stack);
size_t size = stack->available;
// If this is not true, the vacancy information will almost certainly be destroyed:
VM_ASSERT(size <= (stack->size - RB_PAGE_SIZE));
int advice = stack->pool->free_stacks >> 1;
if (DEBUG) fprintf(stderr, "fiber_pool_stack_free: %p+%"PRIuSIZE" [base=%p, size=%"PRIuSIZE"] advice=%d\n", base, size, stack->base, stack->size, advice);
// The pages being used by the stack can be returned back to the system.
// That doesn't change the page mapping, but it does allow the system to
// reclaim the physical memory.
// Since we no longer care about the data itself, we don't need to page
// out to disk, since that is costly. Not all systems support that, so
// we try our best to select the most efficient implementation.
// In addition, it's actually slightly desirable to not do anything here,
// but that results in higher memory usage.
#ifdef __wasi__
// WebAssembly doesn't support madvise, so we just don't do anything.
#elif VM_CHECK_MODE > 0 && defined(MADV_DONTNEED)
if (!advice) advice = MADV_DONTNEED;
// This immediately discards the pages and the memory is reset to zero.
madvise(base, size, advice);
#elif defined(MADV_FREE_REUSABLE)
if (!advice) advice = MADV_FREE_REUSABLE;
// Darwin / macOS / iOS.
// Acknowledge the kernel down to the task info api we make this
// page reusable for future use.
// As for MADV_FREE_REUSABLE below we ensure in the rare occasions the task was not
// completed at the time of the call to re-iterate.
while (madvise(base, size, advice) == -1 && errno == EAGAIN);
#elif defined(MADV_FREE)
if (!advice) advice = MADV_FREE;
// Recent Linux.
madvise(base, size, advice);
#elif defined(MADV_DONTNEED)
if (!advice) advice = MADV_DONTNEED;
// Old Linux.
madvise(base, size, advice);
#elif defined(POSIX_MADV_DONTNEED)
if (!advice) advice = POSIX_MADV_DONTNEED;
// Solaris?
posix_madvise(base, size, advice);
#elif defined(_WIN32)
VirtualAlloc(base, size, MEM_RESET, PAGE_READWRITE);
// Not available in all versions of Windows.
//DiscardVirtualMemory(base, size);
#endif
#if defined(COROUTINE_SANITIZE_ADDRESS)
__asan_poison_memory_region(fiber_pool_stack_poison_base(stack), fiber_pool_stack_poison_size(stack));
#endif
}
// Release and return a stack to the vacancy list.
static void
fiber_pool_stack_release(struct fiber_pool_stack * stack)
{
struct fiber_pool * pool = stack->pool;
struct fiber_pool_vacancy * vacancy = fiber_pool_vacancy_pointer(stack->base, stack->size);
if (DEBUG) fprintf(stderr, "fiber_pool_stack_release: %p used=%"PRIuSIZE"\n", stack->base, stack->pool->used);
// Copy the stack details into the vacancy area:
vacancy->stack = *stack;
// After this point, be careful about updating/using state in stack, since it's copied to the vacancy area.
// Reset the stack pointers and reserve space for the vacancy data:
fiber_pool_vacancy_reset(vacancy);
// Push the vacancy into the vancancies list:
pool->vacancies = fiber_pool_vacancy_push(vacancy, pool->vacancies);
pool->used -= 1;
#ifdef FIBER_POOL_ALLOCATION_FREE
struct fiber_pool_allocation * allocation = stack->allocation;
allocation->used -= 1;
// Release address space and/or dirty memory:
if (allocation->used == 0) {
fiber_pool_allocation_free(allocation);
}
else if (stack->pool->free_stacks) {
fiber_pool_stack_free(&vacancy->stack);
}
#else
// This is entirely optional, but clears the dirty flag from the stack
// memory, so it won't get swapped to disk when there is memory pressure:
if (stack->pool->free_stacks) {
fiber_pool_stack_free(&vacancy->stack);
}
#endif
}
static inline void
ec_switch(rb_thread_t *th, rb_fiber_t *fiber)
{
rb_execution_context_t *ec = &fiber->cont.saved_ec;
#ifdef RUBY_ASAN_ENABLED
ec->machine.asan_fake_stack_handle = asan_get_thread_fake_stack_handle();
#endif
rb_ractor_set_current_ec(th->ractor, th->ec = ec);
// ruby_current_execution_context_ptr = th->ec = ec;
/*
* timer-thread may set trap interrupt on previous th->ec at any time;
* ensure we do not delay (or lose) the trap interrupt handling.
*/
if (th->vm->ractor.main_thread == th &&
rb_signal_buff_size() > 0) {
RUBY_VM_SET_TRAP_INTERRUPT(ec);
}
VM_ASSERT(ec->fiber_ptr->cont.self == 0 || ec->vm_stack != NULL);
}
static inline void
fiber_restore_thread(rb_thread_t *th, rb_fiber_t *fiber)
{
ec_switch(th, fiber);
VM_ASSERT(th->ec->fiber_ptr == fiber);
}
#ifndef COROUTINE_DECL
# define COROUTINE_DECL COROUTINE
#endif
NORETURN(static COROUTINE_DECL fiber_entry(struct coroutine_context * from, struct coroutine_context * to));
static COROUTINE
fiber_entry(struct coroutine_context * from, struct coroutine_context * to)
{
rb_fiber_t *fiber = to->argument;
#if defined(COROUTINE_SANITIZE_ADDRESS)
// Address sanitizer will copy the previous stack base and stack size into
// the "from" fiber. `coroutine_initialize_main` doesn't generally know the
// stack bounds (base + size). Therefore, the main fiber `stack_base` and
// `stack_size` will be NULL/0. It's specifically important in that case to
// get the (base+size) of the previous fiber and save it, so that later when
// we return to the main coroutine, we don't supply (NULL, 0) to
// __sanitizer_start_switch_fiber which royally messes up the internal state
// of ASAN and causes (sometimes) the following message:
// "WARNING: ASan is ignoring requested __asan_handle_no_return"
__sanitizer_finish_switch_fiber(to->fake_stack, (const void**)&from->stack_base, &from->stack_size);
#endif
rb_thread_t *thread = fiber->cont.saved_ec.thread_ptr;
#ifdef COROUTINE_PTHREAD_CONTEXT
ruby_thread_set_native(thread);
#endif
fiber_restore_thread(thread, fiber);
rb_fiber_start(fiber);
#ifndef COROUTINE_PTHREAD_CONTEXT
VM_UNREACHABLE(fiber_entry);
#endif
}
// Initialize a fiber's coroutine's machine stack and vm stack.
static VALUE *
fiber_initialize_coroutine(rb_fiber_t *fiber, size_t * vm_stack_size)
{
struct fiber_pool * fiber_pool = fiber->stack.pool;
rb_execution_context_t *sec = &fiber->cont.saved_ec;
void * vm_stack = NULL;
VM_ASSERT(fiber_pool != NULL);
fiber->stack = fiber_pool_stack_acquire(fiber_pool);
vm_stack = fiber_pool_stack_alloca(&fiber->stack, fiber_pool->vm_stack_size);
*vm_stack_size = fiber_pool->vm_stack_size;
coroutine_initialize(&fiber->context, fiber_entry, fiber_pool_stack_base(&fiber->stack), fiber->stack.available);
// The stack for this execution context is the one we allocated:
sec->machine.stack_start = fiber->stack.current;
sec->machine.stack_maxsize = fiber->stack.available;
fiber->context.argument = (void*)fiber;
return vm_stack;
}
// Release the stack from the fiber, it's execution context, and return it to
// the fiber pool.
static void
fiber_stack_release(rb_fiber_t * fiber)
{
rb_execution_context_t *ec = &fiber->cont.saved_ec;
if (DEBUG) fprintf(stderr, "fiber_stack_release: %p, stack.base=%p\n", (void*)fiber, fiber->stack.base);
// Return the stack back to the fiber pool if it wasn't already:
if (fiber->stack.base) {
fiber_pool_stack_release(&fiber->stack);
fiber->stack.base = NULL;
}
// The stack is no longer associated with this execution context:
rb_ec_clear_vm_stack(ec);
}
static const char *
fiber_status_name(enum fiber_status s)
{
switch (s) {
case FIBER_CREATED: return "created";
case FIBER_RESUMED: return "resumed";
case FIBER_SUSPENDED: return "suspended";
case FIBER_TERMINATED: return "terminated";
}
VM_UNREACHABLE(fiber_status_name);
return NULL;
}
static void
fiber_verify(const rb_fiber_t *fiber)
{
#if VM_CHECK_MODE > 0
VM_ASSERT(fiber->cont.saved_ec.fiber_ptr == fiber);
switch (fiber->status) {
case FIBER_RESUMED:
VM_ASSERT(fiber->cont.saved_ec.vm_stack != NULL);
break;
case FIBER_SUSPENDED:
VM_ASSERT(fiber->cont.saved_ec.vm_stack != NULL);
break;
case FIBER_CREATED:
case FIBER_TERMINATED:
/* TODO */
break;
default:
VM_UNREACHABLE(fiber_verify);
}
#endif
}
inline static void
fiber_status_set(rb_fiber_t *fiber, enum fiber_status s)
{
// if (DEBUG) fprintf(stderr, "fiber: %p, status: %s -> %s\n", (void *)fiber, fiber_status_name(fiber->status), fiber_status_name(s));
VM_ASSERT(!FIBER_TERMINATED_P(fiber));
VM_ASSERT(fiber->status != s);
fiber_verify(fiber);
fiber->status = s;
}
static rb_context_t *
cont_ptr(VALUE obj)
{
rb_context_t *cont;
TypedData_Get_Struct(obj, rb_context_t, &cont_data_type, cont);
return cont;
}
static rb_fiber_t *
fiber_ptr(VALUE obj)
{
rb_fiber_t *fiber;
TypedData_Get_Struct(obj, rb_fiber_t, &fiber_data_type, fiber);
if (!fiber) rb_raise(rb_eFiberError, "uninitialized fiber");
return fiber;
}
NOINLINE(static VALUE cont_capture(volatile int *volatile stat));
#define THREAD_MUST_BE_RUNNING(th) do { \
if (!(th)->ec->tag) rb_raise(rb_eThreadError, "not running thread"); \
} while (0)
rb_thread_t*
rb_fiber_threadptr(const rb_fiber_t *fiber)
{
return fiber->cont.saved_ec.thread_ptr;
}
static VALUE
cont_thread_value(const rb_context_t *cont)
{
return cont->saved_ec.thread_ptr->self;
}
static void
cont_compact(void *ptr)
{
rb_context_t *cont = ptr;