qemu-kvm/SOURCES/kvm-iothread-replace-init_done_cond-with-a-semaphore.patch

118 lines
4.2 KiB
Diff

From 9db6f24509ee8a28818693d6a15257b873d9422a Mon Sep 17 00:00:00 2001
From: Stefan Hajnoczi <stefanha@redhat.com>
Date: Thu, 15 Aug 2019 13:23:11 +0100
Subject: [PATCH 09/10] iothread: replace init_done_cond with a semaphore
RH-Author: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: <20190815132311.22027-3-stefanha@redhat.com>
Patchwork-id: 89996
O-Subject: [RHEL-8.1.0 qemu-kvm PATCH v2 2/2] iothread: replace init_done_cond with a semaphore
Bugzilla: 1687541
RH-Acked-by: Peter Xu <peterx@redhat.com>
RH-Acked-by: John Snow <jsnow@redhat.com>
RH-Acked-by: Markus Armbruster <armbru@redhat.com>
From: Peter Xu <peterx@redhat.com>
Only sending an init-done message using lock+cond seems an overkill to
me. Replacing it with a simpler semaphore.
Meanwhile, init the semaphore unconditionally, then we can destroy it
unconditionally too in finalize which seems cleaner.
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-id: 20190306115532.23025-2-peterx@redhat.com
Message-Id: <20190306115532.23025-2-peterx@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit 21c4d15b4708b7d30c450041a560df670f36cac8)
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
---
include/sysemu/iothread.h | 3 +--
iothread.c | 17 ++++-------------
2 files changed, 5 insertions(+), 15 deletions(-)
diff --git a/include/sysemu/iothread.h b/include/sysemu/iothread.h
index 8a7ac2c..50411ba 100644
--- a/include/sysemu/iothread.h
+++ b/include/sysemu/iothread.h
@@ -27,8 +27,7 @@ typedef struct {
GMainContext *worker_context;
GMainLoop *main_loop;
GOnce once;
- QemuMutex init_done_lock;
- QemuCond init_done_cond; /* is thread initialization done? */
+ QemuSemaphore init_done_sem; /* is thread init done? */
bool stopping; /* has iothread_stop() been called? */
bool running; /* should iothread_run() continue? */
int thread_id;
diff --git a/iothread.c b/iothread.c
index 2fb1cdf..b92232f 100644
--- a/iothread.c
+++ b/iothread.c
@@ -55,10 +55,8 @@ static void *iothread_run(void *opaque)
rcu_register_thread();
my_iothread = iothread;
- qemu_mutex_lock(&iothread->init_done_lock);
iothread->thread_id = qemu_get_thread_id();
- qemu_cond_signal(&iothread->init_done_cond);
- qemu_mutex_unlock(&iothread->init_done_lock);
+ qemu_sem_post(&iothread->init_done_sem);
while (iothread->running) {
aio_poll(iothread->ctx, true);
@@ -111,6 +109,7 @@ static void iothread_instance_init(Object *obj)
iothread->poll_max_ns = IOTHREAD_POLL_MAX_NS_DEFAULT;
iothread->thread_id = -1;
+ qemu_sem_init(&iothread->init_done_sem, 0);
}
static void iothread_instance_finalize(Object *obj)
@@ -119,10 +118,6 @@ static void iothread_instance_finalize(Object *obj)
iothread_stop(iothread);
- if (iothread->thread_id != -1) {
- qemu_cond_destroy(&iothread->init_done_cond);
- qemu_mutex_destroy(&iothread->init_done_lock);
- }
/*
* Before glib2 2.33.10, there is a glib2 bug that GSource context
* pointer may not be cleared even if the context has already been
@@ -141,6 +136,7 @@ static void iothread_instance_finalize(Object *obj)
g_main_context_unref(iothread->worker_context);
iothread->worker_context = NULL;
}
+ qemu_sem_destroy(&iothread->init_done_sem);
}
static void iothread_complete(UserCreatable *obj, Error **errp)
@@ -169,8 +165,6 @@ static void iothread_complete(UserCreatable *obj, Error **errp)
return;
}
- qemu_mutex_init(&iothread->init_done_lock);
- qemu_cond_init(&iothread->init_done_cond);
iothread->once = (GOnce) G_ONCE_INIT;
/* This assumes we are called from a thread with useful CPU affinity for us
@@ -184,12 +178,9 @@ static void iothread_complete(UserCreatable *obj, Error **errp)
g_free(name);
/* Wait for initialization to complete */
- qemu_mutex_lock(&iothread->init_done_lock);
while (iothread->thread_id == -1) {
- qemu_cond_wait(&iothread->init_done_cond,
- &iothread->init_done_lock);
+ qemu_sem_wait(&iothread->init_done_sem);
}
- qemu_mutex_unlock(&iothread->init_done_lock);
}
typedef struct {
--
1.8.3.1