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/*
* Copyright 2009-2015 Samy Al Bahra.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef CK_BACKOFF_H
#define CK_BACKOFF_H
#include <ck_cc.h>
#include <ck_pr.h>
#ifndef CK_BACKOFF_CEILING
#define CK_BACKOFF_CEILING ((1 << 20) - 1)
#endif
#define CK_BACKOFF_INITIALIZER (1 << 9)
typedef unsigned int ck_backoff_t;
/*
* This is a exponential back-off implementation.
*/
CK_CC_INLINE static void
ck_backoff_eb(unsigned int *c)
{
unsigned int i, ceiling;
ceiling = *c;
for (i = 0; i < ceiling; i++)
ck_pr_barrier();
*c = ceiling <<= ceiling < CK_BACKOFF_CEILING;
return;
}
#endif /* CK_BACKOFF_H */
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