From patchwork Fri Feb 8 20:10:43 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bruce Fields X-Patchwork-Id: 10803729 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 89D5A17F0 for ; Fri, 8 Feb 2019 20:11:23 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7DBAF2EA0B for ; Fri, 8 Feb 2019 20:11:23 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 71F4D2EA5B; Fri, 8 Feb 2019 20:11:23 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 6DC3C2EA0B for ; Fri, 8 Feb 2019 20:11:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727505AbfBHULP (ORCPT ); Fri, 8 Feb 2019 15:11:15 -0500 Received: from fieldses.org ([173.255.197.46]:57044 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727324AbfBHUKu (ORCPT ); Fri, 8 Feb 2019 15:10:50 -0500 Received: by fieldses.org (Postfix, from userid 2815) id D87F11EF6; Fri, 8 Feb 2019 15:10:48 -0500 (EST) From: "J. Bruce Fields" To: linux-nfs@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Trond Myklebust , Jeff Layton , David Howells , Tejun Heo , Peter Zijlstra , Shaohua Li , Oleg Nesterov , "J. Bruce Fields" Subject: [PATCH 3/7] kthreads: allow multiple kthreadd's Date: Fri, 8 Feb 2019 15:10:43 -0500 Message-Id: <1549656647-25115-4-git-send-email-bfields@redhat.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1549656647-25115-1-git-send-email-bfields@redhat.com> References: <1549656647-25115-1-git-send-email-bfields@redhat.com> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: "J. Bruce Fields" 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 --- 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 #include +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 #include -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;