[PATCH] Support for freezeable workqueues

Make it possible to create a workqueue the worker thread of which will be
frozen during suspend, along with other kernel threads.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Cc: Nigel Cunningham <nigel@suspend2.net>
Cc: David Chinner <dgc@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h
index 4a3ea83..f0cb1df 100644 (file)
--- a/include/linux/workqueue.h
+++ b/include/linux/workqueue.h
@@ -147,9 +147,11 @@ struct execute_work {
 
 
 extern struct workqueue_struct *__create_workqueue(const char *name,
-                                                   int singlethread);
-#define create_workqueue(name) __create_workqueue((name), 0)
-#define create_singlethread_workqueue(name) __create_workqueue((name), 1)
+                                                   int singlethread,
+                                                   int freezeable);
+#define create_workqueue(name) __create_workqueue((name), 0, 0)
+#define create_freezeable_workqueue(name) __create_workqueue((name), 0, 1)
+#define create_singlethread_workqueue(name) __create_workqueue((name), 1, 0)
 
 extern void destroy_workqueue(struct workqueue_struct *wq);
 

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 8d1e7cb..2945b09 100644 (file)
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -29,6 +29,7 @@
 #include <linux/kthread.h>
 #include <linux/hardirq.h>
 #include <linux/mempolicy.h>
+#include <linux/freezer.h>
 
 /*
  * The per-CPU workqueue (if single thread, we always use the first
@@ -55,6 +56,8 @@ struct cpu_workqueue_struct {
        struct task_struct *thread;
 
        int run_depth;          /* Detect run_workqueue() recursion depth */
+
+       int freezeable;         /* Freeze the thread during suspend */
 } ____cacheline_aligned;
 
 /*
@@ -265,7 +268,8 @@ static int worker_thread(void *__cwq)
        struct k_sigaction sa;
        sigset_t blocked;
 
-       current->flags |= PF_NOFREEZE;
+       if (!cwq->freezeable)
+               current->flags |= PF_NOFREEZE;
 
        set_user_nice(current, -5);
 
@@ -288,6 +292,9 @@ static int worker_thread(void *__cwq)
 
        set_current_state(TASK_INTERRUPTIBLE);
        while (!kthread_should_stop()) {
+               if (cwq->freezeable)
+                       try_to_freeze();
+
                add_wait_queue(&cwq->more_work, &wait);
                if (list_empty(&cwq->worklist))
                        schedule();
@@ -364,7 +371,7 @@ void fastcall flush_workqueue(struct workqueue_struct *wq)
 EXPORT_SYMBOL_GPL(flush_workqueue);
 
 static struct task_struct *create_workqueue_thread(struct workqueue_struct *wq,
-                                                  int cpu)
+                                                  int cpu, int freezeable)
 {
        struct cpu_workqueue_struct *cwq = per_cpu_ptr(wq->cpu_wq, cpu);
        struct task_struct *p;
@@ -374,6 +381,7 @@ static struct task_struct *create_workqueue_thread(struct workqueue_struct *wq,
        cwq->thread = NULL;
        cwq->insert_sequence = 0;
        cwq->remove_sequence = 0;
+       cwq->freezeable = freezeable;
        INIT_LIST_HEAD(&cwq->worklist);
        init_waitqueue_head(&cwq->more_work);
        init_waitqueue_head(&cwq->work_done);
@@ -389,7 +397,7 @@ static struct task_struct *create_workqueue_thread(struct workqueue_struct *wq,
 }
 
 struct workqueue_struct *__create_workqueue(const char *name,
-                                           int singlethread)
+                                           int singlethread, int freezeable)
 {
        int cpu, destroy = 0;
        struct workqueue_struct *wq;
@@ -409,7 +417,7 @@ struct workqueue_struct *__create_workqueue(const char *name,
        mutex_lock(&workqueue_mutex);
        if (singlethread) {
                INIT_LIST_HEAD(&wq->list);
-               p = create_workqueue_thread(wq, singlethread_cpu);
+               p = create_workqueue_thread(wq, singlethread_cpu, freezeable);
                if (!p)
                        destroy = 1;
                else
@@ -417,7 +425,7 @@ struct workqueue_struct *__create_workqueue(const char *name,
        } else {
                list_add(&wq->list, &workqueues);
                for_each_online_cpu(cpu) {
-                       p = create_workqueue_thread(wq, cpu);
+                       p = create_workqueue_thread(wq, cpu, freezeable);
                        if (p) {
                                kthread_bind(p, cpu);
                                wake_up_process(p);
@@ -667,7 +675,7 @@ static int __devinit workqueue_cpu_callback(struct notifier_block *nfb,
                mutex_lock(&workqueue_mutex);
                /* Create a new workqueue thread for it. */
                list_for_each_entry(wq, &workqueues, list) {
-                       if (!create_workqueue_thread(wq, hotcpu)) {
+                       if (!create_workqueue_thread(wq, hotcpu, 0)) {
                                printk("workqueue for %i failed\n", hotcpu);
                                return NOTIFY_BAD;
                        }