mariadb/storage/tokudb/ft-index/ft/workset.h

/* -*- mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*- */
// vim: ft=cpp:expandtab:ts=8:sw=4:softtabstop=4:
#ifndef _TOKU_WORKSET_H
#define _TOKU_WORKSET_H

#ident "$Id$"
/*
COPYING CONDITIONS NOTICE:

  This program is free software; you can redistribute it and/or modify
  it under the terms of version 2 of the GNU General Public License as
  published by the Free Software Foundation, and provided that the
  following conditions are met:

      * Redistributions of source code must retain this COPYING
        CONDITIONS NOTICE, the COPYRIGHT NOTICE (below), the
        DISCLAIMER (below), the UNIVERSITY PATENT NOTICE (below), the
        PATENT MARKING NOTICE (below), and the PATENT RIGHTS
        GRANT (below).

      * Redistributions in binary form must reproduce this COPYING
        CONDITIONS NOTICE, the COPYRIGHT NOTICE (below), the
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        PATENT MARKING NOTICE (below), and the PATENT RIGHTS
        GRANT (below) in the documentation and/or other materials
        provided with the distribution.

  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  02110-1301, USA.

COPYRIGHT NOTICE:

  TokuDB, Tokutek Fractal Tree Indexing Library.
  Copyright (C) 2007-2013 Tokutek, Inc.

DISCLAIMER:

  This program 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
  General Public License for more details.

UNIVERSITY PATENT NOTICE:

  The technology is licensed by the Massachusetts Institute of
  Technology, Rutgers State University of New Jersey, and the Research
  Foundation of State University of New York at Stony Brook under
  United States of America Serial No. 11/760379 and to the patents
  and/or patent applications resulting from it.

PATENT MARKING NOTICE:

  This software is covered by US Patent No. 8,185,551.

PATENT RIGHTS GRANT:

  "THIS IMPLEMENTATION" means the copyrightable works distributed by
  Tokutek as part of the Fractal Tree project.

  "PATENT CLAIMS" means the claims of patents that are owned or
  licensable by Tokutek, both currently or in the future; and that in
  the absence of this license would be infringed by THIS
  IMPLEMENTATION or by using or running THIS IMPLEMENTATION.

  "PATENT CHALLENGE" shall mean a challenge to the validity,
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  THIS IMPLEMENTATION constitutes direct or contributory patent
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  such litigation is filed.  If you or your agent or exclusive
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*/

#ident "Copyright (c) 2007-2013 Tokutek Inc.  All rights reserved."
#ident "The technology is licensed by the Massachusetts Institute of Technology, Rutgers State University of New Jersey, and the Research Foundation of State University of New York at Stony Brook under United States of America Serial No. 11/760379 and to the patents and/or patent applications resulting from it."

#include <toku_list.h>
#include <toku_pthread.h>

// The work struct is the base class for work to be done by some threads
struct work {
    struct toku_list next;
};

// The workset struct contains the set of work to be done by some threads
struct workset {
    toku_mutex_t lock;
    struct toku_list worklist;           // a list of work
    int refs;                            // number of workers that have a reference on the workset
    toku_cond_t worker_wait;     // a condition variable used to wait for all of the worker to release their reference on the workset
};

static inline void 
workset_init(struct workset *ws) {
    toku_mutex_init(&ws->lock, NULL);
    toku_list_init(&ws->worklist);
    ws->refs = 1;      // the calling thread gets a reference
    toku_cond_init(&ws->worker_wait, NULL);
}

static inline void 
workset_destroy(struct workset *ws) {
    invariant(toku_list_empty(&ws->worklist));
    toku_cond_destroy(&ws->worker_wait);
    toku_mutex_destroy(&ws->lock);
}

static inline void 
workset_lock(struct workset *ws) {
    toku_mutex_lock(&ws->lock);
}
        
static inline void 
workset_unlock(struct workset *ws) {
    toku_mutex_unlock(&ws->lock);
}

// Put work in the workset.  Assume the workset is already locked.
static inline void 
workset_put_locked(struct workset *ws, struct work *w) {
    toku_list_push(&ws->worklist, &w->next);
}

// Put work in the workset 
static inline void 
workset_put(struct workset *ws, struct work *w) {
    workset_lock(ws);
    workset_put_locked(ws, w);
    workset_unlock(ws);
}

// Get work from the workset
static inline struct work *
workset_get(struct workset *ws) {
    workset_lock(ws);
    struct work *w = NULL;
    if (!toku_list_empty(&ws->worklist)) {
        struct toku_list *l = toku_list_pop_head(&ws->worklist);
        w = toku_list_struct(l, struct work, next);
    }
    workset_unlock(ws);
    return w;
}

// Add references to the workset
static inline void 
workset_add_ref(struct workset *ws, int refs) {
    workset_lock(ws);
    ws->refs += refs;
    workset_unlock(ws);
}

// Release a reference on the workset
static inline void 
workset_release_ref(struct workset *ws) {
    workset_lock(ws);
    if (--ws->refs == 0) {
        toku_cond_broadcast(&ws->worker_wait);
    }
    workset_unlock(ws);
}

// Wait until all of the worker threads have released their reference on the workset
static inline void 
workset_join(struct workset *ws) {
    workset_lock(ws);
    while (ws->refs != 0) {
        toku_cond_wait(&ws->worker_wait, &ws->lock);
    }
    workset_unlock(ws);
}

#endif