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| author | Oleg Nesterov <oleg@redhat.com> | 2009-06-18 01:27:43 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-06-18 22:03:53 +0200 |
| commit | cdd140bdd6c7bc6395f08877a73c39941501af93 (patch) | |
| tree | 48664b2790fb2b5152bd67bf70fb3405e1ef6e8b | |
| parent | mm: exit.c reorder wait_opts to remove padding on 64 bit builds (diff) | |
| download | linux-cdd140bdd6c7bc6395f08877a73c39941501af93.tar.xz linux-cdd140bdd6c7bc6395f08877a73c39941501af93.zip | |
kthreads: simplify the startup synchronization
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>
Cc: Christoph Hellwig <hch@lst.de>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Vitaliy Gusev <vgusev@openvz.org
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | kernel/kthread.c | 11 |
1 files changed, 4 insertions, 7 deletions
diff --git a/kernel/kthread.c b/kernel/kthread.c index 7fa441333529..bc5d1f0b25a4 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -27,7 +27,6 @@ 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; @@ -75,7 +74,7 @@ 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()) @@ -95,11 +94,10 @@ static void create_kthread(struct kthread_create_info *create) /* We want our own signal handler (we take no signals by default). */ pid = kernel_thread(kthread, create, CLONE_FS | CLONE_FILES | SIGCHLD); - if (pid < 0) + if (pid < 0) { create->result = ERR_PTR(pid); - else - wait_for_completion(&create->started); - complete(&create->done); + complete(&create->done); + } } /** @@ -130,7 +128,6 @@ struct task_struct *kthread_create(int (*threadfn)(void *data), create.threadfn = threadfn; create.data = data; - init_completion(&create.started); init_completion(&create.done); spin_lock(&kthread_create_lock); |