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thread_pthread.h: rename gvl.acquired' to gvl.owner' and document

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`acquired' was an old boolean variable, but nowadays it is a
rb_thread_t pointer;  "gvl.owner" seems like a more appropriate
name.  And document the contended path including waitq, timer,
and timer_err.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64581 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
This commit is contained in:
normal 2018-08-28 00:24:08 +00:00
parent fcaf874585
commit 4d9c23772f
2 changed files with 21 additions and 11 deletions
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14
thread_pthread.c
View File

@ -186,7 +186,7 @@ designate_timer_thread(rb_vm_t *vm)
} }
/* /*
* We become designated timer thread to kick vm->gvl.acquired * We become designated timer thread to kick vm->gvl.owner
* periodically. Continue on old timeout if it expired. * periodically. Continue on old timeout if it expired.
*/ */
static void static void
@ -220,14 +220,14 @@ do_gvl_timer(rb_vm_t *vm, rb_thread_t *th)
* Timeslice. Warning: the process may fork while this * Timeslice. Warning: the process may fork while this
* thread is contending for GVL: * thread is contending for GVL:
*/ */
if (vm->gvl.acquired) timer_thread_function(); if (vm->gvl.owner) timer_thread_function();
vm->gvl.timer = 0; vm->gvl.timer = 0;
} }
static void static void
gvl_acquire_common(rb_vm_t *vm, rb_thread_t *th) gvl_acquire_common(rb_vm_t *vm, rb_thread_t *th)
{ {
if (vm->gvl.acquired) { if (vm->gvl.owner) {
native_thread_data_t *nd = &th->native_thread_data; native_thread_data_t *nd = &th->native_thread_data;
VM_ASSERT(th->unblock.func == 0 && VM_ASSERT(th->unblock.func == 0 &&
@ -242,7 +242,7 @@ gvl_acquire_common(rb_vm_t *vm, rb_thread_t *th)
else { else {
rb_native_cond_wait(&nd->cond.gvlq, &vm->gvl.lock); rb_native_cond_wait(&nd->cond.gvlq, &vm->gvl.lock);
} }
} while (vm->gvl.acquired); } while (vm->gvl.owner);
list_del_init(&nd->node.gvl); list_del_init(&nd->node.gvl);
@ -254,7 +254,7 @@ gvl_acquire_common(rb_vm_t *vm, rb_thread_t *th)
else { /* reset timer if uncontended */ else { /* reset timer if uncontended */
vm->gvl.timer_err = ETIMEDOUT; vm->gvl.timer_err = ETIMEDOUT;
} }
vm->gvl.acquired = th; vm->gvl.owner = th;
if (!vm->gvl.timer) { if (!vm->gvl.timer) {
if (!designate_timer_thread(vm) && !ubf_threads_empty()) { if (!designate_timer_thread(vm) && !ubf_threads_empty()) {
rb_thread_wakeup_timer_thread(-1); rb_thread_wakeup_timer_thread(-1);
@ -274,7 +274,7 @@ static native_thread_data_t *
gvl_release_common(rb_vm_t *vm) gvl_release_common(rb_vm_t *vm)
{ {
native_thread_data_t *next; native_thread_data_t *next;
vm->gvl.acquired = 0; vm->gvl.owner = 0;
next = list_top(&vm->gvl.waitq, native_thread_data_t, node.ubf); next = list_top(&vm->gvl.waitq, native_thread_data_t, node.ubf);
if (next) rb_native_cond_signal(&next->cond.gvlq); if (next) rb_native_cond_signal(&next->cond.gvlq);
@ -333,7 +333,7 @@ gvl_init(rb_vm_t *vm)
rb_native_cond_initialize(&vm->gvl.switch_cond); rb_native_cond_initialize(&vm->gvl.switch_cond);
rb_native_cond_initialize(&vm->gvl.switch_wait_cond); rb_native_cond_initialize(&vm->gvl.switch_wait_cond);
list_head_init(&vm->gvl.waitq); list_head_init(&vm->gvl.waitq);
vm->gvl.acquired = 0; vm->gvl.owner = 0;
vm->gvl.timer = 0; vm->gvl.timer = 0;
vm->gvl.timer_err = ETIMEDOUT; vm->gvl.timer_err = ETIMEDOUT;
vm->gvl.need_yield = 0; vm->gvl.need_yield = 0;

18
thread_pthread.h
View File

@ -47,11 +47,21 @@ typedef struct native_thread_data_struct {
typedef struct rb_global_vm_lock_struct { typedef struct rb_global_vm_lock_struct {
/* fast path */ /* fast path */
const struct rb_thread_struct *acquired; const struct rb_thread_struct *owner;
rb_nativethread_lock_t lock; rb_nativethread_lock_t lock; /* AKA vm->gvl.lock */
/* slow path */ /*
struct list_head waitq; * slow path, protected by vm->gvl.lock
* - @waitq - FIFO queue of threads waiting for GVL
* - @timer - it handles timeslices for @owner. It is any one thread
* in @waitq, there is no @timer if @waitq is empty, but always
* a @timer if @waitq has entries
* - @timer_err tracks timeslice limit, the timeslice only resets
* when pthread_cond_timedwait returns ETIMEDOUT, so frequent
* switching between contended/uncontended GVL won't reset the
* timer.
*/
struct list_head waitq; /* <=> native_thread_data_t.node.ubf */
const struct rb_thread_struct *timer; const struct rb_thread_struct *timer;
int timer_err; int timer_err;