From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3A6E0C433EF for ; Sun, 26 Jun 2022 19:16:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232046AbiFZTQW (ORCPT ); Sun, 26 Jun 2022 15:16:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58164 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232020AbiFZTQV (ORCPT ); Sun, 26 Jun 2022 15:16:21 -0400 Received: from out01.mta.xmission.com (out01.mta.xmission.com [166.70.13.231]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B0A54DF35 for ; Sun, 26 Jun 2022 12:16:20 -0700 (PDT) Received: from in02.mta.xmission.com ([166.70.13.52]:43804) by out01.mta.xmission.com with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.93) (envelope-from ) id 1o5Xk3-00Cq77-RR; Sun, 26 Jun 2022 13:16:19 -0600 Received: from ip68-227-174-4.om.om.cox.net ([68.227.174.4]:57744 helo=email.froward.int.ebiederm.org.xmission.com) by in02.mta.xmission.com with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.93) (envelope-from ) id 1o5Xk2-008ahI-S9; Sun, 26 Jun 2022 13:16:19 -0600 From: "Eric W. Biederman" To: Linus Torvalds Cc: Christian Brauner , Tejun Heo , Petr Mladek , Lai Jiangshan , Michal Hocko , Linux Kernel Mailing List , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Andrew Morton , Oleg Nesterov References: <20220622140853.31383-1-pmladek@suse.com> <874k0863x8.fsf@email.froward.int.ebiederm.org> <87pmiw1fy6.fsf@email.froward.int.ebiederm.org> <87ilonuti2.fsf_-_@email.froward.int.ebiederm.org> Date: Sun, 26 Jun 2022 14:16:12 -0500 In-Reply-To: <87ilonuti2.fsf_-_@email.froward.int.ebiederm.org> (Eric W. Biederman's message of "Sun, 26 Jun 2022 14:14:45 -0500") Message-ID: <877d53utfn.fsf_-_@email.froward.int.ebiederm.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-XM-SPF: eid=1o5Xk2-008ahI-S9;;;mid=<877d53utfn.fsf_-_@email.froward.int.ebiederm.org>;;;hst=in02.mta.xmission.com;;;ip=68.227.174.4;;;frm=ebiederm@xmission.com;;;spf=softfail X-XM-AID: U2FsdGVkX190SQdd+8R3p3eCZ3mGtEfgajVYGJGF7/E= X-SA-Exim-Connect-IP: 68.227.174.4 X-SA-Exim-Mail-From: ebiederm@xmission.com Subject: [PATCH 2/3] kthread: Replace kernel_thread with new_kthread X-SA-Exim-Version: 4.2.1 (built Sat, 08 Feb 2020 21:53:50 +0000) X-SA-Exim-Scanned: Yes (on in02.mta.xmission.com) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org It is desriable to be able to perform all of the kthread setup before the kernel thread is awaked for the first time. To make that possible replace kernel_thread with new_kthread that does all of the same work except it does not call wake_up_new_task. Replace the two uses of kernel_threadd with new_kthread and a call to wake_up_new_task. Signed-off-by: "Eric W. Biederman" --- include/linux/sched/task.h | 2 +- init/main.c | 6 ++---- kernel/fork.c | 4 ++-- kernel/kthread.c | 10 ++++++---- 4 files changed, 11 insertions(+), 11 deletions(-) diff --git a/include/linux/sched/task.h b/include/linux/sched/task.h index d95930e220da..c4c7a0118553 100644 --- a/include/linux/sched/task.h +++ b/include/linux/sched/task.h @@ -91,7 +91,7 @@ extern pid_t kernel_clone(struct kernel_clone_args *kargs); struct task_struct *create_io_thread(int (*fn)(void *), void *arg, int node); struct task_struct *fork_idle(int); struct mm_struct *copy_init_mm(void); -extern pid_t kernel_thread(int (*fn)(void *), void *arg); +extern struct task_struct *new_kthread(int (*fn)(void *), void *arg, int node); extern pid_t user_mode_thread(int (*fn)(void *), void *arg, unsigned long flags); extern long kernel_wait4(pid_t, int __user *, int, struct rusage *); int kernel_wait(pid_t pid, int *stat); diff --git a/init/main.c b/init/main.c index 211d38db0d16..b437581f8001 100644 --- a/init/main.c +++ b/init/main.c @@ -701,10 +701,8 @@ noinline void __ref rest_init(void) rcu_read_unlock(); numa_default_policy(); - pid = kernel_thread(kthreadd, NULL); - rcu_read_lock(); - kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns); - rcu_read_unlock(); + kthreadd_task = new_kthread(kthreadd, NULL, NUMA_NO_NODE); + wake_up_new_task(kthreadd_task); /* * Enable might_sleep() and smp_processor_id() checks. diff --git a/kernel/fork.c b/kernel/fork.c index 65909ded0ea7..794d9f9c78bc 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -2694,7 +2694,7 @@ pid_t kernel_clone(struct kernel_clone_args *args) /* * Create a kernel thread. */ -pid_t kernel_thread(int (*fn)(void *), void *arg) +struct task_struct *new_kthread(int (*fn)(void *), void *arg, int node) { unsigned long flags = CLONE_FS | CLONE_FILES | SIGCHLD; struct kernel_clone_args args = { @@ -2706,7 +2706,7 @@ pid_t kernel_thread(int (*fn)(void *), void *arg) .kthread = 1, }; - return kernel_clone(&args); + return copy_process(NULL, 0, node, &args); } /* diff --git a/kernel/kthread.c b/kernel/kthread.c index c0505e6b7142..8529f6b1582b 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -390,14 +390,14 @@ int tsk_fork_get_node(struct task_struct *tsk) static void create_kthread(struct kthread_create_info *create) { - int pid; + struct task_struct *new; #ifdef CONFIG_NUMA current->pref_node_fork = create->node; #endif /* We want our own signal handler (we take no signals by default). */ - pid = kernel_thread(kthread, create); - if (pid < 0) { + new = new_kthread(kthread, create, NUMA_NO_NODE); + if (IS_ERR(new)) { /* If user was SIGKILLed, I release the structure. */ struct completion *done = xchg(&create->done, NULL); @@ -405,8 +405,10 @@ static void create_kthread(struct kthread_create_info *create) kfree(create); return; } - create->result = ERR_PTR(pid); + create->result = ERR_CAST(new); complete(done); + } else { + wake_up_new_task(new); } } -- 2.35.3