source: trunk/kernel/libk/remote_condvar.h @ 436

Last change on this file since 436 was 23, checked in by alain, 4 years ago

Introduce syscalls.

File size: 6.8 KB
Line 
1/*
2 * remote_condvar.h - distributed kernel condvar definition
3 *
4 * Author  Alain Greiner (2016,2017)
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 _REMOTE_CONDVAR_H_
25#define _REMOTE_CONDVAR_H_
26
27#include <kernel_config.h>
28#include <hal_types.h>
29#include <remote_spinlock.h>
30#include <xlist.h>
31
32/*****************************************************************************************
33 *          This file defines a POSIX compliant condvar.
34 *
35 * It is used by multi-threaded applications to synchronise threads running in
36 * different clusters, as all access functions uses hal_remote_lw() / hal_remote_sw()
37 * portable remote access primitives.
38 *
39 * A condvar is declared by a given user process as a "pthread_cond_t" global variable.
40 * This user type is implemented as an unsigned long, but the value is not used by the
41 * kernel. ALMOS-MKH uses only the condvar virtual address as an identifier.
42 * For each user condvar, ALMOS-MKH creates a kernel "remote_condvar_t" structure,
43 * dynamically allocated in the reference cluster by the remote_condvar_create() function,
44 * and destroyed by the remote_condvar_destroy() function, using RPC if the calling
45 * thread is not running in the reference cluster. The synchronisation is done by the
46 * remote_condvar_wait(), remote_condvar_signal(), remote_convar_broadcast() functions.
47 ****************************************************************************************/
48
49/*****************************************************************************************
50 * This structure defines the condvar descriptor.
51 * - It contains an xlist of all condvars dynamically created by a given process,
52 *   rooted in the reference process descriptor.
53 * - It contains also the root of another xlist of all threads waiting on the condvar,
54 *   resumed by a remote_condvar_signal(), or remote_condvar_broadcast().
55 ****************************************************************************************/
56
57typedef struct remote_condvar_s
58{
59    remote_spinlock_t  lock;     /*! lock protecting the waiting threads list           */
60    intptr_t           ident;    /*! virtual address in user space == identifier        */
61    xlist_entry_t      list;     /*! member of list of condvars in same process         */
62    xlist_entry_t      root;     /*! root of list of waiting threads                    */
63}
64remote_condvar_t;
65
66/*****************************************************************************************
67 * This function returns an extended pointer on the remote condvar identified
68 * by its virtual address in a given user process. It makes an associative search,
69 * scanning the list of condvars rooted in the reference process descriptor.
70 *****************************************************************************************
71 * @ ident    : condvar virtual address, used as identifier.
72 * @ returns extended pointer on condvar if success / returns XPTR_NULL if not found.
73 ****************************************************************************************/
74xptr_t remote_condvar_from_ident( intptr_t  ident );
75
76/*****************************************************************************************
77 * This function implement the pthread_condvar_init() syscall.
78 * It allocates memory for the condvar descriptor in the reference cluster for
79 * the calling process, it initializes the condvar state, and register it in the
80 * list of condvars owned by the reference process.
81 *****************************************************************************************
82 * @ ident       : condvar identifier (virtual address in user space).
83 * @ return 0 if success / return ENOMEM if failure.
84 ****************************************************************************************/
85error_t remote_condvar_create( intptr_t ident );
86
87/*****************************************************************************************
88 * This function implement the pthread_condvar_destroy() syscall.
89 * It releases the memory allocated for the condvar descriptor, and remove the condvar
90 * from the list of condvars owned by the reference process.
91 *****************************************************************************************
92 * @ condvar_xp  : extended pointer on condvar descriptor.
93 ****************************************************************************************/
94void remote_condvar_destroy( xptr_t   condvar_xp );
95
96/*****************************************************************************************
97 * This function implement the pthread_condvar_wait() syscall.
98 * It unlock the mutex.
99 * It register the calling thread in the condvar waiting queue, block the calling thread
100 * on the THREAD_BLOCKED_CONDVAR condition and deschedule.
101 * it lock the mutex.
102 *****************************************************************************************
103 * @ condvar_xp   : extended pointer on condvar descriptor.
104 * @ mutex_xp     : extended pointer on associated mutex descriptor.
105 ****************************************************************************************/
106void remote_condvar_wait( xptr_t   condvar_xp, 
107                          xptr_t   mutex_xp );
108
109/*****************************************************************************************
110 * This function implement the pthread_condvar_signal() syscall.
111 * It unblocks the first waiting thread in the condvar waiting queue.
112 *****************************************************************************************
113 * @ condvar_xp  : extended pointer on condvar descriptor.
114 ****************************************************************************************/
115void remote_condvar_signal( xptr_t   condvar_xp );
116
117/*****************************************************************************************
118 * This function implement the pthread_condvar_broadcast() syscall.
119 * It unblocks all waiting threads in the condvar waiting queue.
120 *****************************************************************************************
121 * @ condvar_xp  : extended pointer on condvar descriptor.
122 ****************************************************************************************/
123void remote_condvar_broadcast( xptr_t   condvar_xp );
124
125
126#endif  /* _REMOTE_BARRIER_H_ */
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