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MDEV-17441 InnoDB transition to C++11 atomics
os0once.h: remove as not used now
This commit is contained in:
Eugene Kosov
parent
adb640e25a
commit
12ce066edf
5 changed files with 1 additions and 123 deletions
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@ -65,7 +65,6 @@ ib_warn_row_too_big(const dict_table_t* table);
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#include "lock0lock.h"
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#include "mach0data.h"
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#include "mem0mem.h"
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#include "os0once.h"
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#include "page0page.h"
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#include "page0zip.h"
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#include "pars0pars.h"
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@ -44,7 +44,6 @@ Created 1/8/1996 Heikki Tuuri
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#include "fts0fts.h"
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#include "buf0buf.h"
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#include "gis0type.h"
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#include "os0once.h"
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#include "fil0fil.h"
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#include "fil0crypt.h"
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#include <sql_const.h>
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@ -1,120 +0,0 @@
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/*****************************************************************************
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Copyright (c) 2014, Oracle and/or its affiliates. All Rights Reserved.
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This program is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free Software
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Foundation; version 2 of the License.
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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 details.
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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.,
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51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA
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*****************************************************************************/
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/**************************************************//**
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@file include/os0once.h
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A class that aids executing a given function exactly once in a multi-threaded
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environment.
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Created Feb 20, 2014 Vasil Dimov
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*******************************************************/
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#ifndef os0once_h
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#define os0once_h
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#include "univ.i"
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#include "ut0ut.h"
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#include "my_cpu.h"
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/** Execute a given function exactly once in a multi-threaded environment
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or wait for the function to be executed by another thread.
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Example usage:
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First the user must create a control variable of type os_once::state_t and
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assign it os_once::NEVER_DONE.
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Then the user must pass this variable, together with a function to be
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executed to os_once::do_or_wait_for_done().
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Multiple threads can call os_once::do_or_wait_for_done() simultaneously with
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the same (os_once::state_t) control variable. The provided function will be
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called exactly once and when os_once::do_or_wait_for_done() returns then this
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function has completed execution, by this or another thread. In other words
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os_once::do_or_wait_for_done() will either execute the provided function or
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will wait for its execution to complete if it is already called by another
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thread or will do nothing if the function has already completed its execution
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earlier.
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This mimics pthread_once(3), but unfortunatelly pthread_once(3) does not
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support passing arguments to the init_routine() function. We should use
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std::call_once() when we start compiling with C++11 enabled. */
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class os_once {
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public:
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/** Control variables' state type */
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typedef ib_uint32_t state_t;
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/** Not yet executed. */
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static const state_t NEVER_DONE = 0;
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/** Currently being executed by this or another thread. */
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static const state_t IN_PROGRESS = 1;
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/** Finished execution. */
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static const state_t DONE = 2;
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/** Call a given function or wait its execution to complete if it is
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already called by another thread.
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@param[in,out] state control variable
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@param[in] do_func function to call
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@param[in,out] do_func_arg an argument to pass to do_func(). */
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static
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void
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do_or_wait_for_done(
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volatile state_t* state,
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void (*do_func)(void*),
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void* do_func_arg)
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{
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int32 oldval = NEVER_DONE;
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/* Avoid calling my_atomic_cas32() in the most common case. */
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if (*state == DONE) {
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return;
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}
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if (my_atomic_cas32((int32*) state, &oldval, IN_PROGRESS)) {
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/* We are the first. Call the function. */
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do_func(do_func_arg);
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my_atomic_store32((int32*) state, DONE);
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} else {
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/* The state is not NEVER_DONE, so either it is
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IN_PROGRESS (somebody is calling the function right
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now or DONE (it has already been called and completed).
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Wait for it to become DONE. */
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for (;;) {
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const state_t s = *state;
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switch (s) {
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case DONE:
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return;
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case IN_PROGRESS:
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break;
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case NEVER_DONE:
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/* fall through */
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default:
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ut_error;
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}
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MY_RELAX_CPU();
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}
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}
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}
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};
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#endif /* os0once_h */
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@ -30,6 +30,7 @@ Created 12/15/2009 Jimmy Yang
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#define srv0mon_h
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#include "univ.i"
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#include "my_atomic.h"
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#ifndef __STDC_LIMIT_MACROS
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/* Required for FreeBSD so that INT64_MAX is defined. */
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@ -28,7 +28,6 @@ Created 9/5/1995 Heikki Tuuri
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#define sync0types_h
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#include <vector>
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#include <my_atomic.h>
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#include "ut0new.h"
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