source: trunk/kernel/libk/barrier.h @ 576

Last change on this file since 576 was 563, checked in by alain, 6 years ago

Complete restructuration of kernel spinlocks.

File size: 2.4 KB
Line 
1/*
2 * barrier.h - Busy-waiting, local, kernel barrier definition
3 *
4 * Author  Alain Greiner (2016,2017,2018)
5 *
6 * Copyright (c) UPMC Sorbonne Universites
7 *
8 * This file is part of ALMOS-MKH.
9 *
10 * ALMOS-MKH is free software; you can redistribute it and/or modify it
11 * under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; version 2.0 of the License.
13 *
14 * ALMOS-MKH is distributed in the hope that it will be useful, but
15 * WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
17 * General Public License for more details.
18 *
19 * You should have received a copy of the GNU General Public License
20 * along with ALMOS-MKH; if not, write to the Free Software Foundation,
21 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
22 */
23
24#ifndef _BARRIER_H_
25#define _BARRIER_H_
26
27#include <kernel_config.h>
28#include <hal_kernel_types.h>
29
30/*****************************************************************************************
31 * This structure defines a "rendez-vous" barrier, that can be used
32 * to synchronise several kernel threads running in the same  cluster.
33 * As it is used in the kernel_init phase, it implements a busy-waiting policy.
34 * It does not need to be initialised, but it must be statically allocated
35 * in the KDATA segment to be properly initialised by the compiler/loader.
36 ****************************************************************************************/
37
38typedef struct barrier_s
39{
40    uint32_t            current;            // number of arrived threads
41    volatile uint32_t   sense;              // barrier state (toggle)
42    uint32_t            padding[(CONFIG_CACHE_LINE_SIZE>>2)-2];
43} 
44barrier_t;
45
46/*****************************************************************************************
47 * This blocking function implements a toggle barrier. It returns only when all
48 * expected threads reach the barrier. It can be used several times without
49 * specific initialisation.
50 *****************************************************************************************
51 * @ barrier : pointer on barrier
52 * @ count   : number of expected thread
53 ****************************************************************************************/
54inline void barrier_wait( barrier_t * barrier, 
55                          uint32_t    count );
56
57
58#endif  /* _BARRIER_H_ */
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