| Message ID | 1549656647-25115-4-git-send-email-bfields@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Eliminate delegation self-conflicts | expand |
I'd like to try to get this in 5.2. Can anyone give me an ACK for the kthread parts? Or tell me who to ask? Let me know if I should resend. Or, of course, tell me if I've missed something and this is all a terrible idea. --b. On Fri, Feb 08, 2019 at 03:10:43PM -0500, J. Bruce Fields wrote: > From: "J. Bruce Fields" <bfields@redhat.com> > > Allow subsystems to run their own kthreadd's. > > I'm experimenting with this to allow nfsd to put its threads into its > own thread group to make it easy for the vfs to tell when nfsd is > breaking one of its own leases. > > Signed-off-by: J. Bruce Fields <bfields@redhat.com> > --- > include/linux/kthread.h | 20 ++++++- > init/main.c | 4 +- > kernel/kthread.c | 113 ++++++++++++++++++++++++++++++---------- > 3 files changed, 107 insertions(+), 30 deletions(-) > > diff --git a/include/linux/kthread.h b/include/linux/kthread.h > index c1961761311d..10b5836dfb2a 100644 > --- a/include/linux/kthread.h > +++ b/include/linux/kthread.h > @@ -6,6 +6,24 @@ > #include <linux/sched.h> > #include <linux/cgroup.h> > > +struct kthread_group { > + char *name; > + spinlock_t create_lock; > + struct list_head create_list; > + struct task_struct *task; > +}; > + > +extern struct kthread_group kthreadd_default; > + > +struct kthread_group *kthread_start_group(char *); > +void kthread_stop_group(struct kthread_group *); > + > +struct task_struct *kthread_group_create_on_node(struct kthread_group *, > + int (*threadfn)(void *data), > + void *data, > + int node, > + const char namefmt[], ...); > + > __printf(4, 5) > struct task_struct *kthread_create_on_node(int (*threadfn)(void *data), > void *data, > @@ -63,7 +81,7 @@ int kthread_park(struct task_struct *k); > void kthread_unpark(struct task_struct *k); > void kthread_parkme(void); > > -int kthreadd(void *unused); > +int kthreadd(void *); > extern struct task_struct *kthreadd_task; > extern int tsk_fork_get_node(struct task_struct *tsk); > > diff --git a/init/main.c b/init/main.c > index e2e80ca3165a..c4ed4d75aca7 100644 > --- a/init/main.c > +++ b/init/main.c > @@ -417,9 +417,9 @@ noinline void __ref rest_init(void) > rcu_read_unlock(); > > numa_default_policy(); > - pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES); > + pid = kernel_thread(kthreadd, &kthreadd_default, CLONE_FS | CLONE_FILES); > rcu_read_lock(); > - kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns); > + kthreadd_default.task = find_task_by_pid_ns(pid, &init_pid_ns); > rcu_read_unlock(); > > /* > diff --git a/kernel/kthread.c b/kernel/kthread.c > index 4428fd586cd8..b515557b98c9 100644 > --- a/kernel/kthread.c > +++ b/kernel/kthread.c > @@ -22,9 +22,44 @@ > #include <linux/uaccess.h> > #include <trace/events/sched.h> > > -static DEFINE_SPINLOCK(kthread_create_lock); > -static LIST_HEAD(kthread_create_list); > -struct task_struct *kthreadd_task; > +struct kthread_group kthreadd_default = { > + .name = "kthreadd", > + .create_lock = __SPIN_LOCK_UNLOCKED(kthreadd_default.create_lock), > + .create_list = LIST_HEAD_INIT(kthreadd_default.create_list), > +}; > + > +void wake_kthreadd(struct kthread_group *kg) > +{ > + wake_up_process(kg->task); > +} > + > +struct kthread_group *kthread_start_group(char *name) > +{ > + struct kthread_group *new; > + struct task_struct *task; > + > + new = kmalloc(sizeof(struct kthread_group), GFP_KERNEL); > + if (!new) > + return ERR_PTR(-ENOMEM); > + spin_lock_init(&new->create_lock); > + INIT_LIST_HEAD(&new->create_list); > + new->name = name; > + task = kthread_run(kthreadd, new, name); > + if (IS_ERR(task)) { > + kfree(new); > + return ERR_CAST(task); > + } > + new->task = task; > + return new; > +} > +EXPORT_SYMBOL_GPL(kthread_start_group); > + > +void kthread_stop_group(struct kthread_group *kg) > +{ > + kthread_stop(kg->task); > + kfree(kg); > +} > +EXPORT_SYMBOL_GPL(kthread_stop_group); > > struct kthread_create_info > { > @@ -279,11 +314,13 @@ static void create_kthread(struct kthread_create_info *create) > } > } > > -static __printf(4, 0) > -struct task_struct *__kthread_create_on_node(int (*threadfn)(void *data), > - void *data, int node, > - const char namefmt[], > - va_list args) > + > +static __printf(5, 0) > +struct task_struct *__kthread_group_create_on_node(struct kthread_group *kg, > + int (*threadfn)(void *data), > + void *data, int node, > + const char namefmt[], > + va_list args) > { > DECLARE_COMPLETION_ONSTACK(done); > struct task_struct *task; > @@ -297,11 +334,11 @@ struct task_struct *__kthread_create_on_node(int (*threadfn)(void *data), > create->node = node; > create->done = &done; > > - spin_lock(&kthread_create_lock); > - list_add_tail(&create->list, &kthread_create_list); > - spin_unlock(&kthread_create_lock); > + spin_lock(&kg->create_lock); > + list_add_tail(&create->list, &kg->create_list); > + spin_unlock(&kg->create_lock); > > - wake_up_process(kthreadd_task); > + wake_kthreadd(kg); > /* > * Wait for completion in killable state, for I might be chosen by > * the OOM killer while kthreadd is trying to allocate memory for > @@ -343,6 +380,25 @@ struct task_struct *__kthread_create_on_node(int (*threadfn)(void *data), > return task; > } > > +__printf(5, 0) > +struct task_struct *kthread_group_create_on_node(struct kthread_group *kg, > + int (*threadfn)(void *data), > + void *data, int node, > + const char namefmt[], > + ...) > +{ > + struct task_struct *task; > + va_list args; > + > + va_start(args, namefmt); > + task = __kthread_group_create_on_node(kg, threadfn, > + data, node, namefmt, args); > + va_end(args); > + > + return task; > +} > +EXPORT_SYMBOL_GPL(kthread_group_create_on_node); > + > /** > * kthread_create_on_node - create a kthread. > * @threadfn: the function to run until signal_pending(current). > @@ -375,7 +431,8 @@ struct task_struct *kthread_create_on_node(int (*threadfn)(void *data), > va_list args; > > va_start(args, namefmt); > - task = __kthread_create_on_node(threadfn, data, node, namefmt, args); > + task = __kthread_group_create_on_node(&kthreadd_default, threadfn, > + data, node, namefmt, args); > va_end(args); > > return task; > @@ -555,30 +612,31 @@ int kthread_stop(struct task_struct *k) > } > EXPORT_SYMBOL(kthread_stop); > > -void kthread_do_work(void) > +void kthread_do_work(struct kthread_group *kg) > { > - spin_lock(&kthread_create_lock); > - while (!list_empty(&kthread_create_list)) { > + spin_lock(&kg->create_lock); > + while (!list_empty(&kg->create_list)) { > struct kthread_create_info *create; > > - create = list_entry(kthread_create_list.next, > + create = list_entry(kg->create_list.next, > struct kthread_create_info, list); > list_del_init(&create->list); > - spin_unlock(&kthread_create_lock); > + spin_unlock(&kg->create_lock); > > create_kthread(create); > > - spin_lock(&kthread_create_lock); > + spin_lock(&kg->create_lock); > } > - spin_unlock(&kthread_create_lock); > + spin_unlock(&kg->create_lock); > } > > -int kthreadd(void *unused) > +int kthreadd(void *data) > { > + struct kthread_group *kg = data; > struct task_struct *tsk = current; > > /* Setup a clean context for our children to inherit. */ > - set_task_comm(tsk, "kthreadd"); > + set_task_comm(tsk, kg->name); > ignore_signals(tsk); > set_cpus_allowed_ptr(tsk, cpu_all_mask); > set_mems_allowed(node_states[N_MEMORY]); > @@ -586,13 +644,13 @@ int kthreadd(void *unused) > current->flags |= PF_NOFREEZE; > cgroup_init_kthreadd(); > > - for (;;) { > + while (current == kthreadd_default.task || !kthread_should_stop()) { > set_current_state(TASK_INTERRUPTIBLE); > - if (list_empty(&kthread_create_list)) > + if (list_empty(&kg->create_list)) > schedule(); > __set_current_state(TASK_RUNNING); > > - kthread_do_work(); > + kthread_do_work(kg); > } > > return 0; > @@ -690,8 +748,9 @@ __kthread_create_worker(int cpu, unsigned int flags, > if (cpu >= 0) > node = cpu_to_node(cpu); > > - task = __kthread_create_on_node(kthread_worker_fn, worker, > - node, namefmt, args); > + task = __kthread_group_create_on_node(&kthreadd_default, > + kthread_worker_fn, > + worker, node, namefmt, args); > if (IS_ERR(task)) > goto fail_task; > > -- > 2.20.1
diff --git a/include/linux/kthread.h b/include/linux/kthread.h index c1961761311d..10b5836dfb2a 100644 --- a/include/linux/kthread.h +++ b/include/linux/kthread.h @@ -6,6 +6,24 @@ #include <linux/sched.h> #include <linux/cgroup.h> +struct kthread_group { + char *name; + spinlock_t create_lock; + struct list_head create_list; + struct task_struct *task; +}; + +extern struct kthread_group kthreadd_default; + +struct kthread_group *kthread_start_group(char *); +void kthread_stop_group(struct kthread_group *); + +struct task_struct *kthread_group_create_on_node(struct kthread_group *, + int (*threadfn)(void *data), + void *data, + int node, + const char namefmt[], ...); + __printf(4, 5) struct task_struct *kthread_create_on_node(int (*threadfn)(void *data), void *data, @@ -63,7 +81,7 @@ int kthread_park(struct task_struct *k); void kthread_unpark(struct task_struct *k); void kthread_parkme(void); -int kthreadd(void *unused); +int kthreadd(void *); extern struct task_struct *kthreadd_task; extern int tsk_fork_get_node(struct task_struct *tsk); diff --git a/init/main.c b/init/main.c index e2e80ca3165a..c4ed4d75aca7 100644 --- a/init/main.c +++ b/init/main.c @@ -417,9 +417,9 @@ noinline void __ref rest_init(void) rcu_read_unlock(); numa_default_policy(); - pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES); + pid = kernel_thread(kthreadd, &kthreadd_default, CLONE_FS | CLONE_FILES); rcu_read_lock(); - kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns); + kthreadd_default.task = find_task_by_pid_ns(pid, &init_pid_ns); rcu_read_unlock(); /* diff --git a/kernel/kthread.c b/kernel/kthread.c index 4428fd586cd8..b515557b98c9 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -22,9 +22,44 @@ #include <linux/uaccess.h> #include <trace/events/sched.h> -static DEFINE_SPINLOCK(kthread_create_lock); -static LIST_HEAD(kthread_create_list); -struct task_struct *kthreadd_task; +struct kthread_group kthreadd_default = { + .name = "kthreadd", + .create_lock = __SPIN_LOCK_UNLOCKED(kthreadd_default.create_lock), + .create_list = LIST_HEAD_INIT(kthreadd_default.create_list), +}; + +void wake_kthreadd(struct kthread_group *kg) +{ + wake_up_process(kg->task); +} + +struct kthread_group *kthread_start_group(char *name) +{ + struct kthread_group *new; + struct task_struct *task; + + new = kmalloc(sizeof(struct kthread_group), GFP_KERNEL); + if (!new) + return ERR_PTR(-ENOMEM); + spin_lock_init(&new->create_lock); + INIT_LIST_HEAD(&new->create_list); + new->name = name; + task = kthread_run(kthreadd, new, name); + if (IS_ERR(task)) { + kfree(new); + return ERR_CAST(task); + } + new->task = task; + return new; +} +EXPORT_SYMBOL_GPL(kthread_start_group); + +void kthread_stop_group(struct kthread_group *kg) +{ + kthread_stop(kg->task); + kfree(kg); +} +EXPORT_SYMBOL_GPL(kthread_stop_group); struct kthread_create_info { @@ -279,11 +314,13 @@ static void create_kthread(struct kthread_create_info *create) } } -static __printf(4, 0) -struct task_struct *__kthread_create_on_node(int (*threadfn)(void *data), - void *data, int node, - const char namefmt[], - va_list args) + +static __printf(5, 0) +struct task_struct *__kthread_group_create_on_node(struct kthread_group *kg, + int (*threadfn)(void *data), + void *data, int node, + const char namefmt[], + va_list args) { DECLARE_COMPLETION_ONSTACK(done); struct task_struct *task; @@ -297,11 +334,11 @@ struct task_struct *__kthread_create_on_node(int (*threadfn)(void *data), create->node = node; create->done = &done; - spin_lock(&kthread_create_lock); - list_add_tail(&create->list, &kthread_create_list); - spin_unlock(&kthread_create_lock); + spin_lock(&kg->create_lock); + list_add_tail(&create->list, &kg->create_list); + spin_unlock(&kg->create_lock); - wake_up_process(kthreadd_task); + wake_kthreadd(kg); /* * Wait for completion in killable state, for I might be chosen by * the OOM killer while kthreadd is trying to allocate memory for @@ -343,6 +380,25 @@ struct task_struct *__kthread_create_on_node(int (*threadfn)(void *data), return task; } +__printf(5, 0) +struct task_struct *kthread_group_create_on_node(struct kthread_group *kg, + int (*threadfn)(void *data), + void *data, int node, + const char namefmt[], + ...) +{ + struct task_struct *task; + va_list args; + + va_start(args, namefmt); + task = __kthread_group_create_on_node(kg, threadfn, + data, node, namefmt, args); + va_end(args); + + return task; +} +EXPORT_SYMBOL_GPL(kthread_group_create_on_node); + /** * kthread_create_on_node - create a kthread. * @threadfn: the function to run until signal_pending(current). @@ -375,7 +431,8 @@ struct task_struct *kthread_create_on_node(int (*threadfn)(void *data), va_list args; va_start(args, namefmt); - task = __kthread_create_on_node(threadfn, data, node, namefmt, args); + task = __kthread_group_create_on_node(&kthreadd_default, threadfn, + data, node, namefmt, args); va_end(args); return task; @@ -555,30 +612,31 @@ int kthread_stop(struct task_struct *k) } EXPORT_SYMBOL(kthread_stop); -void kthread_do_work(void) +void kthread_do_work(struct kthread_group *kg) { - spin_lock(&kthread_create_lock); - while (!list_empty(&kthread_create_list)) { + spin_lock(&kg->create_lock); + while (!list_empty(&kg->create_list)) { struct kthread_create_info *create; - create = list_entry(kthread_create_list.next, + create = list_entry(kg->create_list.next, struct kthread_create_info, list); list_del_init(&create->list); - spin_unlock(&kthread_create_lock); + spin_unlock(&kg->create_lock); create_kthread(create); - spin_lock(&kthread_create_lock); + spin_lock(&kg->create_lock); } - spin_unlock(&kthread_create_lock); + spin_unlock(&kg->create_lock); } -int kthreadd(void *unused) +int kthreadd(void *data) { + struct kthread_group *kg = data; struct task_struct *tsk = current; /* Setup a clean context for our children to inherit. */ - set_task_comm(tsk, "kthreadd"); + set_task_comm(tsk, kg->name); ignore_signals(tsk); set_cpus_allowed_ptr(tsk, cpu_all_mask); set_mems_allowed(node_states[N_MEMORY]); @@ -586,13 +644,13 @@ int kthreadd(void *unused) current->flags |= PF_NOFREEZE; cgroup_init_kthreadd(); - for (;;) { + while (current == kthreadd_default.task || !kthread_should_stop()) { set_current_state(TASK_INTERRUPTIBLE); - if (list_empty(&kthread_create_list)) + if (list_empty(&kg->create_list)) schedule(); __set_current_state(TASK_RUNNING); - kthread_do_work(); + kthread_do_work(kg); } return 0; @@ -690,8 +748,9 @@ __kthread_create_worker(int cpu, unsigned int flags, if (cpu >= 0) node = cpu_to_node(cpu); - task = __kthread_create_on_node(kthread_worker_fn, worker, - node, namefmt, args); + task = __kthread_group_create_on_node(&kthreadd_default, + kthread_worker_fn, + worker, node, namefmt, args); if (IS_ERR(task)) goto fail_task;