1 /* -*- Mode: C; c-basic-offset:4 ; -*- */
2 /*
3 * (C) 2001 by Argonne National Laboratory.
4 * See COPYRIGHT in top-level directory.
5 */
6
7 #include <stdio.h>
8 #include <stdlib.h>
9 #include <assert.h>
10 #include <strings.h>
11
12 #include <mpi.h>
13 #include "muteximpl.h"
14
15
16 /* -- Begin Profiling Symbol Block for routine MPIX_Mutex_unlock */
17 #if defined(HAVE_PRAGMA_WEAK)
18 #pragma weak MPIX_Mutex_unlock = PMPIX_Mutex_unlock
19 #elif defined(HAVE_PRAGMA_HP_SEC_DEF)
20 #pragma _HP_SECONDARY_DEF PMPIX_Mutex_unlock MPIX_Mutex_unlock
21 #elif defined(HAVE_PRAGMA_CRI_DUP)
22 #pragma _CRI duplicate MPIX_Mutex_unlock as PMPIX_Mutex_unlock
23 #endif
24 /* -- End Profiling Symbol Block */
25
26 /* Define MPICH_MPI_FROM_PMPI if weak symbols are not supported to build
27 the MPI routines */
28 #ifndef MPICH_MPI_FROM_PMPI
29 #undef MPIX_Mutex_unlock
30 #define MPIX_Mutex_unlock PMPIX_Mutex_unlock
31 #endif
32
33 #undef FUNCNAME
34 #define FUNCNAME MPIX_Mutex_unlock
35 #undef FCNAME
36 #define FCNAME MPIU_QUOTE(FUNCNAME)
37
38 /** Unlock a mutex.
39 *
40 * @param[in] hdl Mutex group that the mutex belongs to.
41 * @param[in] mutex Desired mutex number [0..count-1]
42 * @param[in] proc Rank of process where the mutex lives
43 * @return MPI status
44 */
MPIX_Mutex_unlock(MPIX_Mutex hdl,int mutex,int proc)45 int MPIX_Mutex_unlock(MPIX_Mutex hdl, int mutex, int proc)
46 {
47 int rank, nproc, i;
48 uint8_t *buf;
49
50 assert(mutex >= 0 && mutex < hdl->max_count);
51
52 MPI_Comm_rank(hdl->comm, &rank);
53 MPI_Comm_size(hdl->comm, &nproc);
54
55 assert(proc >= 0 && proc < nproc);
56
57 buf = malloc(nproc * sizeof(uint8_t));
58 assert(buf != NULL);
59
60 buf[rank] = 0;
61
62 /* Get all data from the lock_buf, except the byte belonging to
63 * me. Set the byte belonging to me to 0. */
64 MPI_Win_lock(MPI_LOCK_EXCLUSIVE, proc, 0, hdl->windows[mutex]);
65
66 MPI_Put(&buf[rank], 1, MPI_BYTE, proc, rank, 1, MPI_BYTE, hdl->windows[mutex]);
67
68 /* Get data to the left of rank */
69 if (rank > 0) {
70 MPI_Get(buf, rank, MPI_BYTE, proc, 0, rank, MPI_BYTE, hdl->windows[mutex]);
71 }
72
73 /* Get data to the right of rank */
74 if (rank < nproc - 1) {
75 MPI_Get(&buf[rank + 1], nproc - 1 - rank, MPI_BYTE, proc, rank + 1, nproc - 1 - rank,
76 MPI_BYTE, hdl->windows[mutex]);
77 }
78
79 MPI_Win_unlock(proc, hdl->windows[mutex]);
80
81 assert(buf[rank] == 0);
82
83 /* Notify the next waiting process, starting to my right for fairness */
84 for (i = 1; i < nproc; i++) {
85 int p = (rank + i) % nproc;
86 if (buf[p] == 1) {
87 debug_print("notifying %d [proc = %d, mutex = %d]\n", p, proc, mutex);
88 MPI_Send(NULL, 0, MPI_BYTE, p, MPI_MUTEX_TAG + mutex, hdl->comm);
89 break;
90 }
91 }
92
93 debug_print("lock released [proc = %d, mutex = %d]\n", proc, mutex);
94 free(buf);
95
96 return MPI_SUCCESS;
97 }
98