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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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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| #ifndef PFS_USER_H
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| #define PFS_USER_H
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| 
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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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| 
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| #include <atomic>
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| 
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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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| 
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| struct PFS_global_param;
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| struct PFS_thread;
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| 
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| /**
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|   @addtogroup Performance_schema_buffers
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|   @{
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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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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|   void carry_memory_stat_delta(PFS_memory_stat_delta *delta, uint index);
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| 
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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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| 
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|   ulonglong m_disconnected_count;
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| 
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| private:
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|   std::atomic<int> m_refcount;
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| };
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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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| 
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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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| 
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| PFS_user *sanitize_user(PFS_user *unsafe);
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| void purge_all_user(void);
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| 
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| 
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| /* For show status. */
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| 
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| extern LF_HASH user_hash;
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| 
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| /** @} */
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| #endif
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| 
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