From 4d9c23772ff75b88aa397d913a0477f233d38541 Mon Sep 17 00:00:00 2001 From: normal Date: Tue, 28 Aug 2018 00:24:08 +0000 Subject: thread_pthread.h: rename `gvl.acquired' to `gvl.owner' and document `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 --- thread_pthread.c | 14 +++++++------- thread_pthread.h | 18 ++++++++++++++---- 2 files changed, 21 insertions(+), 11 deletions(-) diff --git a/thread_pthread.c b/thread_pthread.c index 4f5bc001f4..f5107bd7af 100644 --- a/thread_pthread.c +++ b/thread_pthread.c @@ -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. */ 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 * thread is contending for GVL: */ - if (vm->gvl.acquired) timer_thread_function(); + if (vm->gvl.owner) timer_thread_function(); vm->gvl.timer = 0; } static void 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; VM_ASSERT(th->unblock.func == 0 && @@ -242,7 +242,7 @@ gvl_acquire_common(rb_vm_t *vm, rb_thread_t *th) else { rb_native_cond_wait(&nd->cond.gvlq, &vm->gvl.lock); } - } while (vm->gvl.acquired); + } while (vm->gvl.owner); 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 */ vm->gvl.timer_err = ETIMEDOUT; } - vm->gvl.acquired = th; + vm->gvl.owner = th; if (!vm->gvl.timer) { if (!designate_timer_thread(vm) && !ubf_threads_empty()) { rb_thread_wakeup_timer_thread(-1); @@ -274,7 +274,7 @@ static native_thread_data_t * gvl_release_common(rb_vm_t *vm) { 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); 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_wait_cond); list_head_init(&vm->gvl.waitq); - vm->gvl.acquired = 0; + vm->gvl.owner = 0; vm->gvl.timer = 0; vm->gvl.timer_err = ETIMEDOUT; vm->gvl.need_yield = 0; diff --git a/thread_pthread.h b/thread_pthread.h index c64018bb13..f2b7e598f7 100644 --- a/thread_pthread.h +++ b/thread_pthread.h @@ -47,11 +47,21 @@ typedef struct native_thread_data_struct { typedef struct rb_global_vm_lock_struct { /* fast path */ - const struct rb_thread_struct *acquired; - rb_nativethread_lock_t lock; + const struct rb_thread_struct *owner; + 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; int timer_err; -- cgit v1.2.3