3e111534a1
Session commands are identified by query clasisfier, and added to the session command property list in router client session object. Session commands are then executed in existing backend servers but only one of them will reply to client.
63 lines
1.7 KiB
C
63 lines
1.7 KiB
C
#ifndef _SPINLOCK_H
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#define _SPINLOCK_H
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/*
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* This file is distributed as part of the SkySQL Gateway. It is free
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* software: you can redistribute it and/or modify it under the terms of the
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* GNU General Public License as published by the Free Software Foundation,
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* version 2.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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* FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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* details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program; if not, write to the Free Software Foundation, Inc., 51
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* Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Copyright SkySQL Ab 2013
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*/
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/**
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* @file spinlock.h
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*
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* Spinlock implementation for ther gateway.
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*
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* Spinlocks are cheap locks that can be used to protect short code blocks, they are
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* generally wasteful as any blocked threads will spin, consuming CPU cycles, waiting
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* for the lock to be released. However they are useful in that they do not involve
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* system calls and are light weight when the expected wait time for a lock is low.
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*/
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#include <thread.h>
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#include <stdbool.h>
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typedef struct spinlock {
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int lock;
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#if DEBUG
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int spins;
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int acquired;
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THREAD owner;
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#endif
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} SPINLOCK;
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#ifndef TRUE
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#define TRUE true
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#endif
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#ifndef FALSE
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#define FALSE false
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#endif
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#if DEBUG
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#define SPINLOCK_INIT { 0, 0, 0, NULL }
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#else
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#define SPINLOCK_INIT { 0 }
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#endif
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#define SPINLOCK_IS_LOCKED(l) ((l)->lock != 0 ? true : false)
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extern void spinlock_init(SPINLOCK *lock);
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extern void spinlock_acquire(SPINLOCK *lock);
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extern int spinlock_acquire_nowait(SPINLOCK *lock);
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extern void spinlock_release(SPINLOCK *lock);
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#endif
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