Messages in this thread Patch in this message | | | Date | Fri, 30 Jan 2009 13:33:54 +0100 | From | Oleg Nesterov <> | Subject | [PATCH 2/4] kthreads: simplify the startup synchronization |
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We use two completions two create the kernel thread, this is a bit ugly. kthread() wakes up create_kthread() via ->started, then create_kthread() wakes up the caller kthread_create() via ->done. But kthread() does not need to wait for kthread(), it can just return. Instead kthread() itself can wake up the caller of kthread_create().
Kill kthread_create_info->started, ->done is enough. This improves the scalability a bit and sijmplifies the code.
The only problem if kernel_thread() fails, in that case create_kthread() must do complete(&create->done).
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
--- 6.29-rc3/kernel/kthread.c~2_COMPLETION 2009-01-30 09:46:29.000000000 +0100 +++ 6.29-rc3/kernel/kthread.c 2009-01-30 10:45:18.000000000 +0100 @@ -29,7 +29,6 @@ struct kthread_create_info /* Information passed to kthread() from kthreadd. */ int (*threadfn)(void *data); void *data; - struct completion started; /* Result passed back to kthread_create() from kthreadd. */ struct task_struct *result; @@ -77,7 +76,7 @@ static int kthread(void *_create) /* OK, tell user we're spawned, wait for stop or wakeup */ __set_current_state(TASK_UNINTERRUPTIBLE); create->result = current; - complete(&create->started); + complete(&create->done); schedule(); if (!kthread_should_stop()) @@ -99,10 +98,8 @@ static void create_kthread(struct kthrea pid = kernel_thread(kthread, create, CLONE_FS | CLONE_FILES | SIGCHLD); if (pid < 0) { create->result = ERR_PTR(pid); - } else { - wait_for_completion(&create->started); + complete(&create->done); } - complete(&create->done); } /** @@ -133,7 +130,6 @@ struct task_struct *kthread_create(int ( create.threadfn = threadfn; create.data = data; - init_completion(&create.started); init_completion(&create.done); spin_lock(&kthread_create_lock);
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