![Andy Lutomirski](/assets/img/avatar_default.png)
We currently keep every task's stack around until the task_struct itself is freed. This means that we keep the stack allocation alive for longer than necessary and that, under load, we free stacks in big batches whenever RCU drops the last task reference. Neither of these is good for reuse of cache-hot memory, and freeing in batches prevents us from usefully caching small numbers of vmalloced stacks. On architectures that have thread_info on the stack, we can't easily change this, but on architectures that set THREAD_INFO_IN_TASK, we can free it as soon as the task is dead. Signed-off-by: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jann Horn <jann@thejh.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/08ca06cde00ebed0046c5d26cbbf3fbb7ef5b812.1474003868.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
289 lines
7.5 KiB
C
289 lines
7.5 KiB
C
#ifndef _LINUX__INIT_TASK_H
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#define _LINUX__INIT_TASK_H
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#include <linux/rcupdate.h>
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#include <linux/irqflags.h>
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#include <linux/utsname.h>
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#include <linux/lockdep.h>
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#include <linux/ftrace.h>
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#include <linux/ipc.h>
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#include <linux/pid_namespace.h>
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#include <linux/user_namespace.h>
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#include <linux/securebits.h>
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#include <linux/seqlock.h>
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#include <linux/rbtree.h>
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#include <net/net_namespace.h>
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#include <linux/sched/rt.h>
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#include <asm/thread_info.h>
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#ifdef CONFIG_SMP
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# define INIT_PUSHABLE_TASKS(tsk) \
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.pushable_tasks = PLIST_NODE_INIT(tsk.pushable_tasks, MAX_PRIO),
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#else
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# define INIT_PUSHABLE_TASKS(tsk)
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#endif
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extern struct files_struct init_files;
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extern struct fs_struct init_fs;
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#ifdef CONFIG_CPUSETS
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#define INIT_CPUSET_SEQ(tsk) \
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.mems_allowed_seq = SEQCNT_ZERO(tsk.mems_allowed_seq),
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#else
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#define INIT_CPUSET_SEQ(tsk)
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#endif
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#ifndef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
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#define INIT_PREV_CPUTIME(x) .prev_cputime = { \
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.lock = __RAW_SPIN_LOCK_UNLOCKED(x.prev_cputime.lock), \
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},
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#else
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#define INIT_PREV_CPUTIME(x)
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#endif
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#define INIT_SIGNALS(sig) { \
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.nr_threads = 1, \
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.thread_head = LIST_HEAD_INIT(init_task.thread_node), \
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.wait_chldexit = __WAIT_QUEUE_HEAD_INITIALIZER(sig.wait_chldexit),\
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.shared_pending = { \
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.list = LIST_HEAD_INIT(sig.shared_pending.list), \
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.signal = {{0}}}, \
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.posix_timers = LIST_HEAD_INIT(sig.posix_timers), \
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.cpu_timers = INIT_CPU_TIMERS(sig.cpu_timers), \
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.rlim = INIT_RLIMITS, \
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.cputimer = { \
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.cputime_atomic = INIT_CPUTIME_ATOMIC, \
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.running = false, \
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.checking_timer = false, \
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}, \
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INIT_PREV_CPUTIME(sig) \
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.cred_guard_mutex = \
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__MUTEX_INITIALIZER(sig.cred_guard_mutex), \
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}
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extern struct nsproxy init_nsproxy;
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#define INIT_SIGHAND(sighand) { \
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.count = ATOMIC_INIT(1), \
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.action = { { { .sa_handler = SIG_DFL, } }, }, \
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.siglock = __SPIN_LOCK_UNLOCKED(sighand.siglock), \
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.signalfd_wqh = __WAIT_QUEUE_HEAD_INITIALIZER(sighand.signalfd_wqh), \
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}
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extern struct group_info init_groups;
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#define INIT_STRUCT_PID { \
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.count = ATOMIC_INIT(1), \
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.tasks = { \
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{ .first = NULL }, \
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{ .first = NULL }, \
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{ .first = NULL }, \
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}, \
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.level = 0, \
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.numbers = { { \
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.nr = 0, \
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.ns = &init_pid_ns, \
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.pid_chain = { .next = NULL, .pprev = NULL }, \
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}, } \
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}
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#define INIT_PID_LINK(type) \
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{ \
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.node = { \
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.next = NULL, \
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.pprev = NULL, \
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}, \
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.pid = &init_struct_pid, \
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}
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#ifdef CONFIG_AUDITSYSCALL
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#define INIT_IDS \
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.loginuid = INVALID_UID, \
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.sessionid = (unsigned int)-1,
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#else
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#define INIT_IDS
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#endif
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#ifdef CONFIG_PREEMPT_RCU
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#define INIT_TASK_RCU_TREE_PREEMPT() \
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.rcu_blocked_node = NULL,
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#else
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#define INIT_TASK_RCU_TREE_PREEMPT(tsk)
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#endif
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#ifdef CONFIG_PREEMPT_RCU
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#define INIT_TASK_RCU_PREEMPT(tsk) \
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.rcu_read_lock_nesting = 0, \
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.rcu_read_unlock_special.s = 0, \
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.rcu_node_entry = LIST_HEAD_INIT(tsk.rcu_node_entry), \
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INIT_TASK_RCU_TREE_PREEMPT()
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#else
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#define INIT_TASK_RCU_PREEMPT(tsk)
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#endif
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#ifdef CONFIG_TASKS_RCU
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#define INIT_TASK_RCU_TASKS(tsk) \
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.rcu_tasks_holdout = false, \
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.rcu_tasks_holdout_list = \
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LIST_HEAD_INIT(tsk.rcu_tasks_holdout_list), \
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.rcu_tasks_idle_cpu = -1,
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#else
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#define INIT_TASK_RCU_TASKS(tsk)
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#endif
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extern struct cred init_cred;
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extern struct task_group root_task_group;
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#ifdef CONFIG_CGROUP_SCHED
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# define INIT_CGROUP_SCHED(tsk) \
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.sched_task_group = &root_task_group,
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#else
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# define INIT_CGROUP_SCHED(tsk)
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#endif
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#ifdef CONFIG_PERF_EVENTS
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# define INIT_PERF_EVENTS(tsk) \
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.perf_event_mutex = \
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__MUTEX_INITIALIZER(tsk.perf_event_mutex), \
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.perf_event_list = LIST_HEAD_INIT(tsk.perf_event_list),
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#else
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# define INIT_PERF_EVENTS(tsk)
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#endif
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#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
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# define INIT_VTIME(tsk) \
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.vtime_seqcount = SEQCNT_ZERO(tsk.vtime_seqcount), \
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.vtime_snap = 0, \
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.vtime_snap_whence = VTIME_SYS,
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#else
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# define INIT_VTIME(tsk)
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#endif
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#define INIT_TASK_COMM "swapper"
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#ifdef CONFIG_RT_MUTEXES
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# define INIT_RT_MUTEXES(tsk) \
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.pi_waiters = RB_ROOT, \
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.pi_waiters_leftmost = NULL,
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#else
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# define INIT_RT_MUTEXES(tsk)
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#endif
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#ifdef CONFIG_NUMA_BALANCING
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# define INIT_NUMA_BALANCING(tsk) \
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.numa_preferred_nid = -1, \
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.numa_group = NULL, \
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.numa_faults = NULL,
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#else
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# define INIT_NUMA_BALANCING(tsk)
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#endif
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#ifdef CONFIG_KASAN
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# define INIT_KASAN(tsk) \
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.kasan_depth = 1,
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#else
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# define INIT_KASAN(tsk)
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#endif
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#ifdef CONFIG_THREAD_INFO_IN_TASK
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# define INIT_TASK_TI(tsk) \
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.thread_info = INIT_THREAD_INFO(tsk), \
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.stack_refcount = ATOMIC_INIT(1),
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#else
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# define INIT_TASK_TI(tsk)
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#endif
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/*
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* INIT_TASK is used to set up the first task table, touch at
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* your own risk!. Base=0, limit=0x1fffff (=2MB)
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*/
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#define INIT_TASK(tsk) \
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{ \
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INIT_TASK_TI(tsk) \
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.state = 0, \
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.stack = init_stack, \
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.usage = ATOMIC_INIT(2), \
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.flags = PF_KTHREAD, \
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.prio = MAX_PRIO-20, \
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.static_prio = MAX_PRIO-20, \
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.normal_prio = MAX_PRIO-20, \
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.policy = SCHED_NORMAL, \
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.cpus_allowed = CPU_MASK_ALL, \
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.nr_cpus_allowed= NR_CPUS, \
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.mm = NULL, \
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.active_mm = &init_mm, \
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.restart_block = { \
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.fn = do_no_restart_syscall, \
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}, \
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.se = { \
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.group_node = LIST_HEAD_INIT(tsk.se.group_node), \
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}, \
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.rt = { \
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.run_list = LIST_HEAD_INIT(tsk.rt.run_list), \
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.time_slice = RR_TIMESLICE, \
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}, \
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.tasks = LIST_HEAD_INIT(tsk.tasks), \
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INIT_PUSHABLE_TASKS(tsk) \
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INIT_CGROUP_SCHED(tsk) \
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.ptraced = LIST_HEAD_INIT(tsk.ptraced), \
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.ptrace_entry = LIST_HEAD_INIT(tsk.ptrace_entry), \
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.real_parent = &tsk, \
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.parent = &tsk, \
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.children = LIST_HEAD_INIT(tsk.children), \
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.sibling = LIST_HEAD_INIT(tsk.sibling), \
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.group_leader = &tsk, \
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RCU_POINTER_INITIALIZER(real_cred, &init_cred), \
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RCU_POINTER_INITIALIZER(cred, &init_cred), \
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.comm = INIT_TASK_COMM, \
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.thread = INIT_THREAD, \
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.fs = &init_fs, \
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.files = &init_files, \
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.signal = &init_signals, \
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.sighand = &init_sighand, \
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.nsproxy = &init_nsproxy, \
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.pending = { \
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.list = LIST_HEAD_INIT(tsk.pending.list), \
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.signal = {{0}}}, \
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.blocked = {{0}}, \
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.alloc_lock = __SPIN_LOCK_UNLOCKED(tsk.alloc_lock), \
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.journal_info = NULL, \
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.cpu_timers = INIT_CPU_TIMERS(tsk.cpu_timers), \
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.pi_lock = __RAW_SPIN_LOCK_UNLOCKED(tsk.pi_lock), \
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.timer_slack_ns = 50000, /* 50 usec default slack */ \
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.pids = { \
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[PIDTYPE_PID] = INIT_PID_LINK(PIDTYPE_PID), \
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[PIDTYPE_PGID] = INIT_PID_LINK(PIDTYPE_PGID), \
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[PIDTYPE_SID] = INIT_PID_LINK(PIDTYPE_SID), \
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}, \
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.thread_group = LIST_HEAD_INIT(tsk.thread_group), \
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.thread_node = LIST_HEAD_INIT(init_signals.thread_head), \
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INIT_IDS \
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INIT_PERF_EVENTS(tsk) \
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INIT_TRACE_IRQFLAGS \
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INIT_LOCKDEP \
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INIT_FTRACE_GRAPH \
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INIT_TRACE_RECURSION \
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INIT_TASK_RCU_PREEMPT(tsk) \
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INIT_TASK_RCU_TASKS(tsk) \
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INIT_CPUSET_SEQ(tsk) \
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INIT_RT_MUTEXES(tsk) \
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INIT_PREV_CPUTIME(tsk) \
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INIT_VTIME(tsk) \
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INIT_NUMA_BALANCING(tsk) \
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INIT_KASAN(tsk) \
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}
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#define INIT_CPU_TIMERS(cpu_timers) \
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{ \
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LIST_HEAD_INIT(cpu_timers[0]), \
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LIST_HEAD_INIT(cpu_timers[1]), \
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LIST_HEAD_INIT(cpu_timers[2]), \
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}
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/* Attach to the init_task data structure for proper alignment */
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#define __init_task_data __attribute__((__section__(".data..init_task")))
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#endif
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