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authorPetr Mladek <pmladek@suse.com>2016-10-11 23:55:30 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2016-10-12 01:06:33 +0300
commitfbae2d44aa1df72d0154be77eb4d71e1e34c0f8f (patch)
tree917022c9eadb5baa36b4e3f86e2095fd1abaf93c /include/linux/kthread.h
parent255451e45345bcd19e79f25e9afc0b9e14ccb104 (diff)
downloadlinux-fbae2d44aa1df72d0154be77eb4d71e1e34c0f8f.tar.xz
kthread: add kthread_create_worker*()
Kthread workers are currently created using the classic kthread API, namely kthread_run(). kthread_worker_fn() is passed as the @threadfn parameter. This patch defines kthread_create_worker() and kthread_create_worker_on_cpu() functions that hide implementation details. They enforce using kthread_worker_fn() for the main thread. But I doubt that there are any plans to create any alternative. In fact, I think that we do not want any alternative main thread because it would be hard to support consistency with the rest of the kthread worker API. The naming and function of kthread_create_worker() is inspired by the workqueues API like the rest of the kthread worker API. The kthread_create_worker_on_cpu() variant is motivated by the original kthread_create_on_cpu(). Note that we need to bind per-CPU kthread workers already when they are created. It makes the life easier. kthread_bind() could not be used later for an already running worker. This patch does _not_ convert existing kthread workers. The kthread worker API need more improvements first, e.g. a function to destroy the worker. IMPORTANT: kthread_create_worker_on_cpu() allows to use any format of the worker name, in compare with kthread_create_on_cpu(). The good thing is that it is more generic. The bad thing is that most users will need to pass the cpu number in two parameters, e.g. kthread_create_worker_on_cpu(cpu, "helper/%d", cpu). To be honest, the main motivation was to avoid the need for an empty va_list. The only legal way was to create a helper function that would be called with an empty list. Other attempts caused compilation warnings or even errors on different architectures. There were also other alternatives, for example, using #define or splitting __kthread_create_worker(). The used solution looked like the least ugly. Link: http://lkml.kernel.org/r/1470754545-17632-6-git-send-email-pmladek@suse.com Signed-off-by: Petr Mladek <pmladek@suse.com> Acked-by: Tejun Heo <tj@kernel.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Borislav Petkov <bp@suse.de> Cc: Michal Hocko <mhocko@suse.cz> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/kthread.h')
-rw-r--r--include/linux/kthread.h7
1 files changed, 7 insertions, 0 deletions
diff --git a/include/linux/kthread.h b/include/linux/kthread.h
index e2b095b8ca47..daeb2befbabf 100644
--- a/include/linux/kthread.h
+++ b/include/linux/kthread.h
@@ -124,6 +124,13 @@ extern void __kthread_init_worker(struct kthread_worker *worker,
int kthread_worker_fn(void *worker_ptr);
+__printf(1, 2)
+struct kthread_worker *
+kthread_create_worker(const char namefmt[], ...);
+
+struct kthread_worker *
+kthread_create_worker_on_cpu(int cpu, const char namefmt[], ...);
+
bool kthread_queue_work(struct kthread_worker *worker,
struct kthread_work *work);
void kthread_flush_work(struct kthread_work *work);