From d0e2fce5366bff40cf2bf48d2f6ff72b4d8de124 Mon Sep 17 00:00:00 2001 From: "Aneesh Kumar K.V" Date: Thu, 9 Jun 2011 23:11:06 +0530 Subject: [PATCH] coroutine: implement coroutines using gthread MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On platforms that don't support makecontext(3) use gthread based coroutine implementation. Darwin has makecontext(3) but getcontext(3) is stubbed out to return ENOTSUP. Andreas Färber debugged this and contributed the ./configure test which solves the issue for Darwin/ppc64 (and ppc) v10.5. [Original patch by Aneesh, made consistent with coroutine-ucontext.c and switched to GStaticPrivate by Stefan. Tested on Linux and OpenBSD.] Signed-off-by: Aneesh Kumar K.V Signed-off-by: Stefan Hajnoczi --- Makefile.objs | 4 ++ configure | 18 ++++++ coroutine-gthread.c | 131 ++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 153 insertions(+) create mode 100644 coroutine-gthread.c diff --git a/Makefile.objs b/Makefile.objs index 28e1762463..5679e1fa06 100644 --- a/Makefile.objs +++ b/Makefile.objs @@ -13,7 +13,11 @@ oslib-obj-$(CONFIG_POSIX) += oslib-posix.o qemu-thread-posix.o ####################################################################### # coroutines coroutine-obj-y = qemu-coroutine.o +ifeq ($(CONFIG_UCONTEXT_COROUTINE),y) coroutine-obj-$(CONFIG_POSIX) += coroutine-ucontext.o +else +coroutine-obj-$(CONFIG_POSIX) += coroutine-gthread.o +endif coroutine-obj-$(CONFIG_WIN32) += coroutine-win32.o ####################################################################### diff --git a/configure b/configure index 77194cf9a7..1eed0cd585 100755 --- a/configure +++ b/configure @@ -2540,6 +2540,20 @@ EOF fi fi +########################################## +# check if we have makecontext + +ucontext_coroutine=no +if test "$darwin" != "yes"; then + cat > $TMPC << EOF +#include +int main(void) { makecontext(0, 0, 0); } +EOF + if compile_prog "" "" ; then + ucontext_coroutine=yes + fi +fi + ########################################## # End of CC checks # After here, no more $cc or $ld runs @@ -3015,6 +3029,10 @@ if test "$rbd" = "yes" ; then echo "CONFIG_RBD=y" >> $config_host_mak fi +if test "$ucontext_coroutine" = "yes" ; then + echo "CONFIG_UCONTEXT_COROUTINE=y" >> $config_host_mak +fi + # USB host support case "$usb" in linux) diff --git a/coroutine-gthread.c b/coroutine-gthread.c new file mode 100644 index 0000000000..f09877e14f --- /dev/null +++ b/coroutine-gthread.c @@ -0,0 +1,131 @@ +/* + * GThread coroutine initialization code + * + * Copyright (C) 2006 Anthony Liguori + * Copyright (C) 2011 Aneesh Kumar K.V + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.0 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, see . + */ + +#include +#include "qemu-common.h" +#include "qemu-coroutine-int.h" + +typedef struct { + Coroutine base; + GThread *thread; + bool runnable; + CoroutineAction action; +} CoroutineGThread; + +static GCond *coroutine_cond; +static GStaticMutex coroutine_lock = G_STATIC_MUTEX_INIT; +static GStaticPrivate coroutine_key = G_STATIC_PRIVATE_INIT; + +static void __attribute__((constructor)) coroutine_init(void) +{ + if (!g_thread_supported()) { + g_thread_init(NULL); + } + + coroutine_cond = g_cond_new(); +} + +static void coroutine_wait_runnable_locked(CoroutineGThread *co) +{ + while (!co->runnable) { + g_cond_wait(coroutine_cond, g_static_mutex_get_mutex(&coroutine_lock)); + } +} + +static void coroutine_wait_runnable(CoroutineGThread *co) +{ + g_static_mutex_lock(&coroutine_lock); + coroutine_wait_runnable_locked(co); + g_static_mutex_unlock(&coroutine_lock); +} + +static gpointer coroutine_thread(gpointer opaque) +{ + CoroutineGThread *co = opaque; + + g_static_private_set(&coroutine_key, co, NULL); + coroutine_wait_runnable(co); + co->base.entry(co->base.entry_arg); + qemu_coroutine_switch(&co->base, co->base.caller, COROUTINE_TERMINATE); + return NULL; +} + +Coroutine *qemu_coroutine_new(void) +{ + CoroutineGThread *co; + + co = qemu_mallocz(sizeof(*co)); + co->thread = g_thread_create_full(coroutine_thread, co, 0, TRUE, TRUE, + G_THREAD_PRIORITY_NORMAL, NULL); + if (!co->thread) { + qemu_free(co); + return NULL; + } + return &co->base; +} + +void qemu_coroutine_delete(Coroutine *co_) +{ + CoroutineGThread *co = DO_UPCAST(CoroutineGThread, base, co_); + + g_thread_join(co->thread); + qemu_free(co); +} + +CoroutineAction qemu_coroutine_switch(Coroutine *from_, + Coroutine *to_, + CoroutineAction action) +{ + CoroutineGThread *from = DO_UPCAST(CoroutineGThread, base, from_); + CoroutineGThread *to = DO_UPCAST(CoroutineGThread, base, to_); + + g_static_mutex_lock(&coroutine_lock); + from->runnable = false; + from->action = action; + to->runnable = true; + to->action = action; + g_cond_broadcast(coroutine_cond); + + if (action != COROUTINE_TERMINATE) { + coroutine_wait_runnable_locked(from); + } + g_static_mutex_unlock(&coroutine_lock); + return from->action; +} + +Coroutine *qemu_coroutine_self(void) +{ + CoroutineGThread *co = g_static_private_get(&coroutine_key); + + if (!co) { + co = qemu_mallocz(sizeof(*co)); + co->runnable = true; + g_static_private_set(&coroutine_key, co, (GDestroyNotify)qemu_free); + } + + return &co->base; +} + +bool qemu_in_coroutine(void) +{ + CoroutineGThread *co = g_static_private_get(&coroutine_key); + + return co && co->base.caller; +}