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	PFS_atomic class contains wrappers around my_atomic_* operations, which
are macros to GNU atomic operations (__atomic_*). Due to different
implementations of compilers, clang may encounter errors when compiling
on x86_32 architecture.
The following functions are replaced with C++ std::atomic type in
performance schema code base:
  - PFS_atomic::store_*()
      -> my_atomic_store*
        -> __atomic_store_n()
    => std::atomic<T>::store()
  - PFS_atomic::load_*()
      -> my_atomic_load*
        -> __atomic_load_n()
    => std::atomic<T>::load()
  - PFS_atomic::add_*()
      -> my_atomic_add*
        -> __atomic_fetch_add()
    => std::atomic<T>::fetch_add()
  - PFS_atomic::cas_*()
    -> my_atomic_cas*
      -> __atomic_compare_exchange_n()
    => std::atomic<T>::compare_exchange_strong()
and PFS_atomic class could be dropped completely.
Note that in the wrapper memory order passed to original GNU atomic
extensions are hard-coded as `__ATOMIC_SEQ_CST`, which is equivalent to
`std::memory_order_seq_cst` in C++, and is the default parameter for
std::atomic_* functions.
All new code of the whole pull request, including one or several files
that are either new files or modified ones, are contributed under the
BSD-new license. I am contributing on behalf of my employer Amazon Web
Services.
		
	
			
		
			
				
	
	
		
			124 lines
		
	
	
	
		
			2.9 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			124 lines
		
	
	
	
		
			2.9 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
/* Copyright (c) 2010, 2023, Oracle and/or its affiliates.
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  This program is free software; you can redistribute it and/or modify
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  it under the terms of the GNU General Public License, version 2.0,
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  as published by the Free Software Foundation.
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  This program is also distributed with certain software (including
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  but not limited to OpenSSL) that is licensed under separate terms,
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  as designated in a particular file or component or in included license
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  documentation.  The authors of MySQL hereby grant you an additional
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  permission to link the program and your derivative works with the
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  separately licensed software that they have included with MySQL.
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  This program is distributed in the hope that it will be useful,
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  but WITHOUT ANY WARRANTY; without even the implied warranty of
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  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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  GNU General Public License, version 2.0, for more details.
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  You should have received a copy of the GNU General Public License
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  along with this program; if not, write to the Free Software
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  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335  USA */
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#ifndef PFS_USER_H
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#define PFS_USER_H
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/**
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  @file storage/perfschema/pfs_user.h
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  Performance schema user (declarations).
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*/
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#include <atomic>
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#include "pfs_lock.h"
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#include "lf.h"
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#include "pfs_con_slice.h"
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struct PFS_global_param;
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struct PFS_thread;
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/**
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  @addtogroup Performance_schema_buffers
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  @{
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*/
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/** Hash key for a user. */
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struct PFS_user_key
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{
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  /**
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    Hash search key.
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    This has to be a string for LF_HASH,
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    the format is "<username><0x00>"
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  */
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  char m_hash_key[USERNAME_LENGTH + 1];
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  uint m_key_length;
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};
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/** Per user statistics. */
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struct PFS_ALIGNED PFS_user : public PFS_connection_slice
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{
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public:
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  inline void init_refcount(void)
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  {
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    m_refcount.store(1);
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  }
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  inline int get_refcount(void)
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  {
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    return m_refcount.load();
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  }
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  inline void inc_refcount(void)
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  {
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    m_refcount.fetch_add(1);
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  }
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  inline void dec_refcount(void)
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  {
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    m_refcount.fetch_sub(1);
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  }
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  void aggregate(bool alive);
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  void aggregate_waits(void);
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  void aggregate_stages(void);
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  void aggregate_statements(void);
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  void aggregate_transactions(void);
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  void aggregate_memory(bool alive);
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  void aggregate_status(void);
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  void aggregate_stats(void);
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  void release(void);
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  void carry_memory_stat_delta(PFS_memory_stat_delta *delta, uint index);
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  /** Internal lock. */
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  pfs_lock m_lock;
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  PFS_user_key m_key;
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  const char *m_username;
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  uint m_username_length;
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  ulonglong m_disconnected_count;
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private:
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  std::atomic<int> m_refcount;
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};
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int init_user(const PFS_global_param *param);
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void cleanup_user(void);
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int init_user_hash(const PFS_global_param *param);
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void cleanup_user_hash(void);
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PFS_user *
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find_or_create_user(PFS_thread *thread,
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                    const char *username, uint username_length);
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PFS_user *sanitize_user(PFS_user *unsafe);
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void purge_all_user(void);
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/* For show status. */
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extern LF_HASH user_hash;
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/** @} */
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#endif
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