/usr/src/blcr-0.8.5/libcr/cr_yield.h is in blcr-dkms 0.8.5-2.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 | /*
* Berkeley Lab Checkpoint/Restart (BLCR) for Linux is Copyright (c)
* 2003, The Regents of the University of California, through Lawrence
* Berkeley National Laboratory (subject to receipt of any required
* approvals from the U.S. Dept. of Energy). All rights reserved.
*
* Portions may be copyrighted by others, as may be noted in specific
* copyright notices within specific files.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* $Id: cr_yield.h,v 1.11 2008/04/23 01:39:19 phargrov Exp $
*
*
* cr_yield.h: macros for yielding
*/
#ifndef _CR_YIELD_H
#define _CR_YIELD_H 1
#include "blcr_config.h"
#include <time.h>
#include <signal.h>
/* how many calls to cri_sched_yield() before sleeping */
#define CRI_MAX_YIELD 50 /* times to yield before sleeping */
/* How many nanoseconds to sleep, must be larger than 2ms
or the kernel might just busy wait without yielding. */
#define CRI_SLEEP_NS 2000001
CR_INLINE void cri_yield(int *count)
{
static const struct timespec ts = {tv_sec: 0, tv_nsec: CRI_SLEEP_NS};
if ((*count)++ < CRI_MAX_YIELD) {
/* Try to yielding to allow the lock to be released.
If we have higher priority than the thread which holds
the lock then this won't actually let that thread run. */
(void)__cri_sched_yield(NULL);
} else {
/* Try sleeping to allow the lock to be released.
By sleeping for > 2ms we ensure that the kernel will
actually sleep, rather than busy wait as it may for
some realtime threads. */
(void)__cri_nanosleep(&ts, NULL, NULL);
*count = 0;
}
}
#if 0
# include <stdio.h>
# define CRI_YIELD_DEBUG(COND) fprintf(stderr, "Yield: " #COND "\n")
#else
# define CRI_YIELD_DEBUG(COND) do {} while (0)
#endif
#define CRI_DO_YIELD_WHILE_COND(COND) \
do { \
int _count = 0; \
do { \
CRI_YIELD_DEBUG(COND); \
cri_yield(&_count); \
} while (COND); \
} while(0)
#define CRI_WHILE_COND_YIELD(COND) \
do { \
int _count = 0; \
while (COND) { \
CRI_YIELD_DEBUG(COND); \
cri_yield(&_count); \
} \
} while(0)
#endif /* _CR_YIELD_H */
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