From patchwork Mon Dec 2 08:35:13 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zhang Yi X-Patchwork-Id: 11268781 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 4A2EF188B for ; Mon, 2 Dec 2019 08:14:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 32971218AC for ; Mon, 2 Dec 2019 08:14:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727356AbfLBIOZ (ORCPT ); Mon, 2 Dec 2019 03:14:25 -0500 Received: from szxga07-in.huawei.com ([45.249.212.35]:44682 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725977AbfLBIOZ (ORCPT ); Mon, 2 Dec 2019 03:14:25 -0500 Received: from DGGEMS405-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id C0039D5F8B839CDB57B6; Mon, 2 Dec 2019 16:14:17 +0800 (CST) Received: from huawei.com (10.175.124.28) by DGGEMS405-HUB.china.huawei.com (10.3.19.205) with Microsoft SMTP Server id 14.3.439.0; Mon, 2 Dec 2019 16:14:08 +0800 From: "zhangyi (F)" To: CC: , , , , , , , , , , , Subject: [PATCH 4.4 1/7] sched/core: Allow putting thread_info into task_struct Date: Mon, 2 Dec 2019 16:35:13 +0800 Message-ID: <20191202083519.23138-2-yi.zhang@huawei.com> X-Mailer: git-send-email 2.17.2 In-Reply-To: <20191202083519.23138-1-yi.zhang@huawei.com> References: <20191202083519.23138-1-yi.zhang@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.175.124.28] X-CFilter-Loop: Reflected Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org From: Andy Lutomirski commit c65eacbe290b8141554c71b2c94489e73ade8c8d upstream. If an arch opts in by setting CONFIG_THREAD_INFO_IN_TASK_STRUCT, then thread_info is defined as a single 'u32 flags' and is the first entry of task_struct. thread_info::task is removed (it serves no purpose if thread_info is embedded in task_struct), and thread_info::cpu gets its own slot in task_struct. This is heavily based on a patch written by Linus. Originally-from: Linus Torvalds Signed-off-by: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Jann Horn Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/a0898196f0476195ca02713691a5037a14f2aac5.1473801993.git.luto@kernel.org Signed-off-by: Ingo Molnar Signed-off-by: zhangyi (F) --- include/linux/init_task.h | 9 +++++++++ include/linux/sched.h | 36 ++++++++++++++++++++++++++++++++++-- include/linux/thread_info.h | 15 +++++++++++++++ init/Kconfig | 7 +++++++ init/init_task.c | 7 +++++-- kernel/sched/sched.h | 4 ++++ 6 files changed, 74 insertions(+), 4 deletions(-) diff --git a/include/linux/init_task.h b/include/linux/init_task.h index 1c1ff7e4faa4..d25d3f70ee99 100644 --- a/include/linux/init_task.h +++ b/include/linux/init_task.h @@ -15,6 +15,8 @@ #include #include +#include + #ifdef CONFIG_SMP # define INIT_PUSHABLE_TASKS(tsk) \ .pushable_tasks = PLIST_NODE_INIT(tsk.pushable_tasks, MAX_PRIO), @@ -183,12 +185,19 @@ extern struct task_group root_task_group; # define INIT_KASAN(tsk) #endif +#ifdef CONFIG_THREAD_INFO_IN_TASK +# define INIT_TASK_TI(tsk) .thread_info = INIT_THREAD_INFO(tsk), +#else +# define INIT_TASK_TI(tsk) +#endif + /* * INIT_TASK is used to set up the first task table, touch at * your own risk!. Base=0, limit=0x1fffff (=2MB) */ #define INIT_TASK(tsk) \ { \ + INIT_TASK_TI(tsk) \ .state = 0, \ .stack = &init_thread_info, \ .usage = ATOMIC_INIT(2), \ diff --git a/include/linux/sched.h b/include/linux/sched.h index 1218980f53de..d6b2e77aad3f 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1389,6 +1389,13 @@ struct tlbflush_unmap_batch { }; struct task_struct { +#ifdef CONFIG_THREAD_INFO_IN_TASK + /* + * For reasons of header soup (see current_thread_info()), this + * must be the first element of task_struct. + */ + struct thread_info thread_info; +#endif volatile long state; /* -1 unrunnable, 0 runnable, >0 stopped */ void *stack; atomic_t usage; @@ -1398,6 +1405,9 @@ struct task_struct { #ifdef CONFIG_SMP struct llist_node wake_entry; int on_cpu; +#ifdef CONFIG_THREAD_INFO_IN_TASK + unsigned int cpu; /* current CPU */ +#endif unsigned int wakee_flips; unsigned long wakee_flip_decay_ts; struct task_struct *last_wakee; @@ -2440,7 +2450,9 @@ extern void set_curr_task(int cpu, struct task_struct *p); void yield(void); union thread_union { +#ifndef CONFIG_THREAD_INFO_IN_TASK struct thread_info thread_info; +#endif unsigned long stack[THREAD_SIZE/sizeof(long)]; }; @@ -2840,10 +2852,26 @@ static inline void threadgroup_change_end(struct task_struct *tsk) cgroup_threadgroup_change_end(tsk); } -#ifndef __HAVE_THREAD_FUNCTIONS +#ifdef CONFIG_THREAD_INFO_IN_TASK + +static inline struct thread_info *task_thread_info(struct task_struct *task) +{ + return &task->thread_info; +} +static inline void *task_stack_page(const struct task_struct *task) +{ + return task->stack; +} +#define setup_thread_stack(new,old) do { } while(0) +static inline unsigned long *end_of_stack(const struct task_struct *task) +{ + return task->stack; +} + +#elif !defined(__HAVE_THREAD_FUNCTIONS) #define task_thread_info(task) ((struct thread_info *)(task)->stack) -#define task_stack_page(task) ((task)->stack) +#define task_stack_page(task) ((void *)(task)->stack) static inline void setup_thread_stack(struct task_struct *p, struct task_struct *org) { @@ -3135,7 +3163,11 @@ static inline void ptrace_signal_wake_up(struct task_struct *t, bool resume) static inline unsigned int task_cpu(const struct task_struct *p) { +#ifdef CONFIG_THREAD_INFO_IN_TASK + return p->cpu; +#else return task_thread_info(p)->cpu; +#endif } static inline int task_node(const struct task_struct *p) diff --git a/include/linux/thread_info.h b/include/linux/thread_info.h index 646891f3bc1e..2813de75a96e 100644 --- a/include/linux/thread_info.h +++ b/include/linux/thread_info.h @@ -13,6 +13,21 @@ struct timespec; struct compat_timespec; +#ifdef CONFIG_THREAD_INFO_IN_TASK +struct thread_info { + u32 flags; /* low level flags */ +}; + +#define INIT_THREAD_INFO(tsk) \ +{ \ + .flags = 0, \ +} +#endif + +#ifdef CONFIG_THREAD_INFO_IN_TASK +#define current_thread_info() ((struct thread_info *)current) +#endif + /* * System call restart block. */ diff --git a/init/Kconfig b/init/Kconfig index 47b0bdcf33c2..5dec7d424980 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -26,6 +26,13 @@ config IRQ_WORK config BUILDTIME_EXTABLE_SORT bool +config THREAD_INFO_IN_TASK + bool + help + Select this to move thread_info off the stack into task_struct. To + make this work, an arch will need to remove all thread_info fields + except flags and fix any runtime bugs. + menu "General setup" config BROKEN diff --git a/init/init_task.c b/init/init_task.c index ba0a7f362d9e..11f83be1fa79 100644 --- a/init/init_task.c +++ b/init/init_task.c @@ -22,5 +22,8 @@ EXPORT_SYMBOL(init_task); * Initial thread structure. Alignment of this is handled by a special * linker map entry. */ -union thread_union init_thread_union __init_task_data = - { INIT_THREAD_INFO(init_task) }; +union thread_union init_thread_union __init_task_data = { +#ifndef CONFIG_THREAD_INFO_IN_TASK + INIT_THREAD_INFO(init_task) +#endif +}; diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 8b96df04ba78..8afd9d62c56e 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -978,7 +978,11 @@ static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu) * per-task data have been completed by this moment. */ smp_wmb(); +#ifdef CONFIG_THREAD_INFO_IN_TASK + p->cpu = cpu; +#else task_thread_info(p)->cpu = cpu; +#endif p->wake_cpu = cpu; #endif }