(Fixed to remove the latent mention of syncthreads).
This patch implements freezer support for workqueues. The current
refrigerator implementation makes all workqueues NOFREEZE, regardless of
whether they need to be or not.
While this doesn't appear to have caused any problems with swsusp (ie
Pavel's version) to date, this is no guarantee for the future.
Furthermore, it seems better to me to treat kernel and userspace threads
consistently, and it also enables us to err on the side of caution by
default with new workqueues.
Queues can be made unfreezable via the new kthread_nonfreeze_run,
create_nofreeze_workqueue and create_nofreeze_singlethread_workqueue
calls, which take the same parameters as kthread_run, create_workqueue
and create_singlethread_workqueue respectively. Existing call syntax is
unchanged and the vast majority of current workqueue calls are therefore
unaffected.
As far as Suspend2 goes, I don't rate this as critical. May save your
hard disk partition one day, but that depends upon what workqueues get
implemented in the future, what out of tree ones do and whether I've
missed good rationale for having nofreeze on existing in tree instances.
If you must flame me, call me overly careful :>.
Regards,
Nigel
Signed-off by: Nigel Cunningham <nigel@xxxxxxxxxxxx>
drivers/acpi/osl.c | 2 +-
drivers/block/ll_rw_blk.c | 2 +-
drivers/char/hvc_console.c | 2 +-
drivers/char/hvcs.c | 2 +-
drivers/input/serio/serio.c | 2 +-
drivers/md/dm-crypt.c | 2 +-
drivers/scsi/hosts.c | 2 +-
drivers/usb/net/pegasus.c | 2 +-
include/linux/kthread.h | 20 ++++++++++++++++++--
include/linux/workqueue.h | 9 ++++++---
kernel/kthread.c | 23 ++++++++++++++++++++++-
kernel/sched.c | 4 ++--
kernel/softirq.c | 3 +--
kernel/workqueue.c | 21 ++++++++++++---------
14 files changed, 69 insertions(+), 27 deletions(-)
diff -ruNp 400-workthreads.patch-old/drivers/acpi/osl.c 400-workthreads.patch-new/drivers/acpi/osl.c
--- 400-workthreads.patch-old/drivers/acpi/osl.c 2005-07-18 06:36:41.000000000 +1000
+++ 400-workthreads.patch-new/drivers/acpi/osl.c 2005-07-20 08:52:31.000000000 +1000
@@ -98,7 +98,7 @@ acpi_os_initialize1(void)
return AE_NULL_ENTRY;
}
#endif
- kacpid_wq = create_singlethread_workqueue("kacpid");
+ kacpid_wq = create_nofreeze_singlethread_workqueue("kacpid");
BUG_ON(!kacpid_wq);
return AE_OK;
diff -ruNp 400-workthreads.patch-old/drivers/block/ll_rw_blk.c 400-workthreads.patch-new/drivers/block/ll_rw_blk.c
--- 400-workthreads.patch-old/drivers/block/ll_rw_blk.c 2005-07-18 06:36:42.000000000 +1000
+++ 400-workthreads.patch-new/drivers/block/ll_rw_blk.c 2005-07-21 00:44:30.000000000 +1000
@@ -3215,7 +3215,7 @@ EXPORT_SYMBOL(kblockd_flush);
int __init blk_dev_init(void)
{
- kblockd_workqueue = create_workqueue("kblockd");
+ kblockd_workqueue = create_nofreeze_workqueue("kblockd");
if (!kblockd_workqueue)
panic("Failed to create kblockd\n");
diff -ruNp 400-workthreads.patch-old/drivers/char/hvc_console.c 400-workthreads.patch-new/drivers/char/hvc_console.c
--- 400-workthreads.patch-old/drivers/char/hvc_console.c 2005-07-18 06:36:43.000000000 +1000
+++ 400-workthreads.patch-new/drivers/char/hvc_console.c 2005-07-20 08:52:31.000000000 +1000
@@ -844,7 +844,7 @@ int __init hvc_init(void)
/* Always start the kthread because there can be hotplug vty adapters
* added later. */
- hvc_task = kthread_run(khvcd, NULL, "khvcd");
+ hvc_task = kthread_nofreeze_run(khvcd, NULL, "khvcd");
if (IS_ERR(hvc_task)) {
panic("Couldn't create kthread for console.\n");
put_tty_driver(hvc_driver);
diff -ruNp 400-workthreads.patch-old/drivers/char/hvcs.c 400-workthreads.patch-new/drivers/char/hvcs.c
--- 400-workthreads.patch-old/drivers/char/hvcs.c 2005-07-18 06:36:43.000000000 +1000
+++ 400-workthreads.patch-new/drivers/char/hvcs.c 2005-07-20 08:52:31.000000000 +1000
@@ -1403,7 +1403,7 @@ static int __init hvcs_module_init(void)
return -ENOMEM;
}
- hvcs_task = kthread_run(khvcsd, NULL, "khvcsd");
+ hvcs_task = kthread_nofreeze_run(khvcsd, NULL, "khvcsd");
if (IS_ERR(hvcs_task)) {
printk(KERN_ERR "HVCS: khvcsd creation failed. Driver not loaded.\n");
kfree(hvcs_pi_buff);
diff -ruNp 400-workthreads.patch-old/drivers/input/serio/serio.c 400-workthreads.patch-new/drivers/input/serio/serio.c
--- 400-workthreads.patch-old/drivers/input/serio/serio.c 2005-07-21 15:29:32.000000000 +1000
+++ 400-workthreads.patch-new/drivers/input/serio/serio.c 2005-07-20 08:52:31.000000000 +1000
@@ -889,7 +889,7 @@ irqreturn_t serio_interrupt(struct serio
static int __init serio_init(void)
{
- serio_task = kthread_run(serio_thread, NULL, "kseriod");
+ serio_task = kthread_nofreeze_run(serio_thread, NULL, "kseriod");
if (IS_ERR(serio_task)) {
printk(KERN_ERR "serio: Failed to start kseriod\n");
return PTR_ERR(serio_task);
diff -ruNp 400-workthreads.patch-old/drivers/md/dm-crypt.c 400-workthreads.patch-new/drivers/md/dm-crypt.c
--- 400-workthreads.patch-old/drivers/md/dm-crypt.c 2005-07-18 06:36:47.000000000 +1000
+++ 400-workthreads.patch-new/drivers/md/dm-crypt.c 2005-07-20 08:52:31.000000000 +1000
@@ -926,7 +926,7 @@ static int __init dm_crypt_init(void)
if (!_crypt_io_pool)
return -ENOMEM;
- _kcryptd_workqueue = create_workqueue("kcryptd");
+ _kcryptd_workqueue = create_nofreeze_workqueue("kcryptd");
if (!_kcryptd_workqueue) {
r = -ENOMEM;
DMERR(PFX "couldn't create kcryptd");
diff -ruNp 400-workthreads.patch-old/drivers/scsi/hosts.c 400-workthreads.patch-new/drivers/scsi/hosts.c
--- 400-workthreads.patch-old/drivers/scsi/hosts.c 2005-07-18 06:36:54.000000000 +1000
+++ 400-workthreads.patch-new/drivers/scsi/hosts.c 2005-07-20 08:52:31.000000000 +1000
@@ -132,7 +132,7 @@ int scsi_add_host(struct Scsi_Host *shos
if (shost->transportt->create_work_queue) {
snprintf(shost->work_q_name, KOBJ_NAME_LEN, "scsi_wq_%d",
shost->host_no);
- shost->work_q = create_singlethread_workqueue(
+ shost->work_q = create_nofreeze_singlethread_workqueue(
shost->work_q_name);
if (!shost->work_q)
goto out_free_shost_data;
diff -ruNp 400-workthreads.patch-old/drivers/usb/net/pegasus.c 400-workthreads.patch-new/drivers/usb/net/pegasus.c
--- 400-workthreads.patch-old/drivers/usb/net/pegasus.c 2005-07-18 06:36:58.000000000 +1000
+++ 400-workthreads.patch-new/drivers/usb/net/pegasus.c 2005-07-20 08:52:31.000000000 +1000
@@ -1412,7 +1412,7 @@ static struct usb_driver pegasus_driver
static int __init pegasus_init(void)
{
pr_info("%s: %s, " DRIVER_DESC "\n", driver_name, DRIVER_VERSION);
- pegasus_workqueue = create_singlethread_workqueue("pegasus");
+ pegasus_workqueue = create_nofreeze_singlethread_workqueue("pegasus");
if (!pegasus_workqueue)
return -ENOMEM;
return usb_register(&pegasus_driver);
diff -ruNp 400-workthreads.patch-old/include/linux/kthread.h 400-workthreads.patch-new/include/linux/kthread.h
--- 400-workthreads.patch-old/include/linux/kthread.h 2004-11-03 21:51:12.000000000 +1100
+++ 400-workthreads.patch-new/include/linux/kthread.h 2005-07-20 15:11:37.000000000 +1000
@@ -27,6 +27,14 @@ struct task_struct *kthread_create(int (
void *data,
const char namefmt[], ...);
+struct task_struct *_kthread_create(int (*threadfn)(void *data),
+ void *data,
+ unsigned long freezer_flags,
+ const char namefmt[], ...);
+
+#define kthread_nofreeze_create(threadfn, data, namefmt, args...) \
+ _kthread_create(threadfn, data, PF_NOFREEZE, namefmt, ##args)
+
/**
* kthread_run: create and wake a thread.
* @threadfn: the function to run until signal_pending(current).
@@ -35,15 +43,23 @@ struct task_struct *kthread_create(int (
*
* Description: Convenient wrapper for kthread_create() followed by
* wake_up_process(). Returns the kthread, or ERR_PTR(-ENOMEM). */
-#define kthread_run(threadfn, data, namefmt, ...) \
+#define kthread_run(threadfn, data, namefmt, args...) \
({ \
struct task_struct *__k \
- = kthread_create(threadfn, data, namefmt, ## __VA_ARGS__); \
+ = kthread_create(threadfn, data, namefmt, ##args); \
if (!IS_ERR(__k)) \
wake_up_process(__k); \
__k; \
})
+#define kthread_nofreeze_run(threadfn, data, namefmt, args...) \
+({ \
+ struct task_struct *__k = kthread_nofreeze_create(threadfn, data, \
+ namefmt, ##args); \
+ if (!IS_ERR(__k)) \
+ wake_up_process(__k); \
+ __k; \
+})
/**
* kthread_bind: bind a just-created kthread to a cpu.
* @k: thread created by kthread_create().
diff -ruNp 400-workthreads.patch-old/include/linux/workqueue.h 400-workthreads.patch-new/include/linux/workqueue.h
--- 400-workthreads.patch-old/include/linux/workqueue.h 2005-06-20 11:47:30.000000000 +1000
+++ 400-workthreads.patch-new/include/linux/workqueue.h 2005-07-20 16:21:55.000000000 +1000
@@ -51,9 +51,12 @@ struct work_struct {
} while (0)
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,
+ unsigned long freezer_flag);
+#define create_workqueue(name) __create_workqueue((name), 0, 0)
+#define create_nofreeze_workqueue(name) __create_workqueue((name), 0, PF_NOFREEZE)
+#define create_singlethread_workqueue(name) __create_workqueue((name), 1, 0)
+#define create_nofreeze_singlethread_workqueue(name) __create_workqueue((name), 1, PF_NOFREEZE)
extern void destroy_workqueue(struct workqueue_struct *wq);
diff -ruNp 400-workthreads.patch-old/kernel/kthread.c 400-workthreads.patch-new/kernel/kthread.c
--- 400-workthreads.patch-old/kernel/kthread.c 2005-06-20 11:47:31.000000000 +1000
+++ 400-workthreads.patch-new/kernel/kthread.c 2005-07-20 15:35:10.000000000 +1000
@@ -25,6 +25,7 @@ struct kthread_create_info
/* Information passed to kthread() from keventd. */
int (*threadfn)(void *data);
void *data;
+ unsigned long freezer_flags;
struct completion started;
/* Result passed back to kthread_create() from keventd. */
@@ -86,6 +87,10 @@ static int kthread(void *_create)
/* By default we can run anywhere, unlike keventd. */
set_cpus_allowed(current, CPU_MASK_ALL);
+ /* Set our freezer flags */
+ current->flags &= ~PF_NOFREEZE;
+ current->flags |= (create->freezer_flags & PF_NOFREEZE);
+
/* OK, tell user we're spawned, wait for stop or wakeup */
__set_current_state(TASK_INTERRUPTIBLE);
complete(&create->started);
@@ -119,8 +124,9 @@ static void keventd_create_kthread(void
complete(&create->done);
}
-struct task_struct *kthread_create(int (*threadfn)(void *data),
+struct task_struct *_kthread_create(int (*threadfn)(void *data),
void *data,
+ unsigned long freezer_flags,
const char namefmt[],
...)
{
@@ -129,6 +135,7 @@ struct task_struct *kthread_create(int (
create.threadfn = threadfn;
create.data = data;
+ create.freezer_flags = freezer_flags;
init_completion(&create.started);
init_completion(&create.done);
@@ -151,6 +158,20 @@ struct task_struct *kthread_create(int (
return create.result;
}
+
+struct task_struct *kthread_create(int (*threadfn)(void *data),
+ void *data,
+ const char namefmt[], ...)
+{
+ char result[TASK_COMM_LEN];
+
+ va_list args;
+ va_start(args, namefmt);
+ vsnprintf(result, TASK_COMM_LEN, namefmt, args);
+ va_end(args);
+ return _kthread_create(threadfn, data, 0, result);
+}
+
EXPORT_SYMBOL(kthread_create);
void kthread_bind(struct task_struct *k, unsigned int cpu)
diff -ruNp 400-workthreads.patch-old/kernel/sched.c 400-workthreads.patch-new/kernel/sched.c
--- 400-workthreads.patch-old/kernel/sched.c 2005-07-21 15:29:30.000000000 +1000
+++ 400-workthreads.patch-new/kernel/sched.c 2005-07-21 15:29:50.000000000 +1000
@@ -4580,10 +4580,10 @@ static int migration_call(struct notifie
switch (action) {
case CPU_UP_PREPARE:
- p = kthread_create(migration_thread, hcpu, "migration/%d",cpu);
+ p = kthread_create(migration_thread, hcpu,
+ "migration/%d",cpu);
if (IS_ERR(p))
return NOTIFY_BAD;
- p->flags |= PF_NOFREEZE;
kthread_bind(p, cpu);
/* Must be high prio: stop_machine expects to yield to it. */
rq = task_rq_lock(p, &flags);
diff -ruNp 400-workthreads.patch-old/kernel/softirq.c 400-workthreads.patch-new/kernel/softirq.c
--- 400-workthreads.patch-old/kernel/softirq.c 2005-06-20 11:47:32.000000000 +1000
+++ 400-workthreads.patch-new/kernel/softirq.c 2005-07-20 08:52:31.000000000 +1000
@@ -350,7 +350,6 @@ void __init softirq_init(void)
static int ksoftirqd(void * __bind_cpu)
{
set_user_nice(current, 19);
- current->flags |= PF_NOFREEZE;
set_current_state(TASK_INTERRUPTIBLE);
@@ -456,7 +455,7 @@ static int __devinit cpu_callback(struct
case CPU_UP_PREPARE:
BUG_ON(per_cpu(tasklet_vec, hotcpu).list);
BUG_ON(per_cpu(tasklet_hi_vec, hotcpu).list);
- p = kthread_create(ksoftirqd, hcpu, "ksoftirqd/%d", hotcpu);
+ p = kthread_nofreeze_create(ksoftirqd, hcpu, "ksoftirqd/%d", hotcpu);
if (IS_ERR(p)) {
printk("ksoftirqd for %i failed\n", hotcpu);
return NOTIFY_BAD;
diff -ruNp 400-workthreads.patch-old/kernel/workqueue.c 400-workthreads.patch-new/kernel/workqueue.c
--- 400-workthreads.patch-old/kernel/workqueue.c 2005-06-20 11:47:32.000000000 +1000
+++ 400-workthreads.patch-new/kernel/workqueue.c 2005-07-21 00:39:28.000000000 +1000
@@ -186,8 +186,6 @@ static int worker_thread(void *__cwq)
struct k_sigaction sa;
sigset_t blocked;
- current->flags |= PF_NOFREEZE;
-
set_user_nice(current, -5);
/* Block and flush all signals */
@@ -208,6 +206,7 @@ static int worker_thread(void *__cwq)
schedule();
else
__set_current_state(TASK_RUNNING);
+ try_to_freeze();
remove_wait_queue(&cwq->more_work, &wait);
if (!list_empty(&cwq->worklist))
@@ -277,7 +276,8 @@ void fastcall flush_workqueue(struct wor
}
static struct task_struct *create_workqueue_thread(struct workqueue_struct *wq,
- int cpu)
+ int cpu,
+ unsigned long freezer_flags)
{
struct cpu_workqueue_struct *cwq = wq->cpu_wq + cpu;
struct task_struct *p;
@@ -292,9 +292,11 @@ static struct task_struct *create_workqu
init_waitqueue_head(&cwq->work_done);
if (is_single_threaded(wq))
- p = kthread_create(worker_thread, cwq, "%s", wq->name);
+ p = _kthread_create(worker_thread, cwq, freezer_flags,
+ "%s", wq->name);
else
- p = kthread_create(worker_thread, cwq, "%s/%d", wq->name, cpu);
+ p = _kthread_create(worker_thread, cwq, freezer_flags,
+ "%s/%d", wq->name, cpu);
if (IS_ERR(p))
return NULL;
cwq->thread = p;
@@ -302,7 +304,8 @@ static struct task_struct *create_workqu
}
struct workqueue_struct *__create_workqueue(const char *name,
- int singlethread)
+ int singlethread,
+ unsigned long freezer_flags)
{
int cpu, destroy = 0;
struct workqueue_struct *wq;
@@ -320,7 +323,7 @@ struct workqueue_struct *__create_workqu
lock_cpu_hotplug();
if (singlethread) {
INIT_LIST_HEAD(&wq->list);
- p = create_workqueue_thread(wq, 0);
+ p = create_workqueue_thread(wq, 0, freezer_flags);
if (!p)
destroy = 1;
else
@@ -330,7 +333,7 @@ struct workqueue_struct *__create_workqu
list_add(&wq->list, &workqueues);
spin_unlock(&workqueue_lock);
for_each_online_cpu(cpu) {
- p = create_workqueue_thread(wq, cpu);
+ p = create_workqueue_thread(wq, cpu, freezer_flags);
if (p) {
kthread_bind(p, cpu);
wake_up_process(p);
@@ -540,7 +543,7 @@ static int __devinit workqueue_cpu_callb
void init_workqueues(void)
{
hotcpu_notifier(workqueue_cpu_callback, 0);
- keventd_wq = create_workqueue("events");
+ keventd_wq = create_nofreeze_workqueue("events");
BUG_ON(!keventd_wq);
}
--
Evolution.
Enumerate the requirements.
Consider the interdependencies.
Calculate the probabilities.
