add a basic spinlock, which based on a ticket lock
This commit is contained in:
Stefan Lankes
parent
949cbb5119
commit
ab28a5e612
3 changed files with 198 additions and 0 deletions
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@ -125,6 +125,8 @@ static inline size_t lsb(size_t i)
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#define NOP4 asm volatile ("nop;nop;nop;nop")
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/// A eight-instruction-do-nothing
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#define NOP8 asm volatile ("nop;nop;nop;nop;nop;nop;nop;nop")
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/// The PAUSE instruction provides a hint to the processor that the code sequence is a spin-wait loop.
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#define PAUSE asm volatile ("pause")
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#ifdef __cplusplus
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}
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132
include/eduos/spinlock.h
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132
include/eduos/spinlock.h
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@ -0,0 +1,132 @@
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/*
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* Copyright (c) 2011, Stefan Lankes, RWTH Aachen University
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* * Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this
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* software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
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* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/**
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* @author Stefan Lankes
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* @file include/eduos/spinlock.h
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* @brief Spinlock functions
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*/
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#ifndef __SPINLOCK_H__
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#define __SPINLOCK_H__
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#include <eduos/stddef.h>
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#include <eduos/spinlock_types.h>
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#include <eduos/tasks_types.h>
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#include <eduos/errno.h>
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#include <asm/atomic.h>
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#include <asm/processor.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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/** @brief Initialization of a spinlock
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*
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* Initialize each spinlock before use!
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*
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* @param s Pointer to the spinlock structure to initialize.
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* @return
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* - 0 on success
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* - -EINVAL (-22) on failure
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*/
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inline static int spinlock_init(spinlock_t* s) {
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if (BUILTIN_EXPECT(!s, 0))
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return -EINVAL;
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atomic_int32_set(&s->queue, 0);
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atomic_int32_set(&s->dequeue, 1);
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s->owner = MAX_TASKS;
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s->counter = 0;
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return 0;
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}
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/** @brief Destroy spinlock after use
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* @return
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* - 0 on success
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* - -EINVAL (-22) on failure
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*/
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inline static int spinlock_destroy(spinlock_t* s) {
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if (BUILTIN_EXPECT(!s, 0))
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return -EINVAL;
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s->owner = MAX_TASKS;
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s->counter = 0;
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return 0;
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}
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/** @brief Lock spinlock at entry of critical section
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* @return
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* - 0 on success
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* - -EINVAL (-22) on failure
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*/
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inline static int spinlock_lock(spinlock_t* s) {
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int32_t ticket;
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if (BUILTIN_EXPECT(!s, 0))
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return -EINVAL;
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if (s->owner == current_task->id) {
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s->counter++;
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return 0;
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}
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ticket = atomic_int32_add(&s->queue, 1);
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while(atomic_int32_read(&s->dequeue) != ticket) {
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PAUSE;
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}
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s->owner = current_task->id;
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s->counter = 1;
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return 0;
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}
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/** @brief Unlock spinlock on exit of critical section
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* @return
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* - 0 on success
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* - -EINVAL (-22) on failure
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*/
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inline static int spinlock_unlock(spinlock_t* s) {
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if (BUILTIN_EXPECT(!s, 0))
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return -EINVAL;
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s->counter--;
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if (!s->counter) {
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s->owner = MAX_TASKS;
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atomic_int32_inc(&s->dequeue);
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}
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return 0;
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}
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#ifdef __cplusplus
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}
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#endif
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#endif
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64
include/eduos/spinlock_types.h
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64
include/eduos/spinlock_types.h
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@ -0,0 +1,64 @@
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/*
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* Copyright (c) 2011, Stefan Lankes, RWTH Aachen University
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* * Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this
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* software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
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* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/**
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* @author Stefan Lankes
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* @file include/eduos/spinlock_types.h
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* @brief Spinlock type definition
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*/
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#ifndef __SPINLOCK_TYPES_H__
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#define __SPINLOCK_TYPES_H__
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#include <eduos/stddef.h>
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#include <asm/atomic.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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/** @brief Spinlock structure */
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typedef struct spinlock {
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/// Internal queue
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atomic_int32_t queue;
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/// Internal dequeue
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atomic_int32_t dequeue;
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/// Owner of this spinlock structure
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tid_t owner;
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/// Internal counter var
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uint32_t counter;
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} spinlock_t;
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/// Macro for spinlock initialization
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#define SPINLOCK_INIT { ATOMIC_INIT(0), ATOMIC_INIT(1), MAX_TASKS, 0}
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#ifdef __cplusplus
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}
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#endif
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#endif
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