摘要：开始用创建，最后用销毁。中间是对进行赋值。和当前线程有关的是。然后把需要的内容取出来并赋值给主要是对三个变量赋值，，。因为是，所以其本身对执行并没有影响，我们可以把子线程的设置为。
预处理
当一个新的连接进来时，MySQL会创建对应的thread(pfs.cc)：
/**
Implementation of the thread instrumentation interface.
@sa PSI_v1::spawn_thread.
*/
int pfs_spawn_thread_v1(PSI_thread_key key,
my_thread_handle *thread, const my_thread_attr_t *attr,
void *(*start_routine)(void*), void *arg)
{
PFS_spawn_thread_arg *psi_arg;
PFS_thread *parent;
/* psi_arg can not be global, and can not be a local variable. */
psi_arg= (PFS_spawn_thread_arg*) my_malloc(PSI_NOT_INSTRUMENTED,
sizeof(PFS_spawn_thread_arg),
MYF(MY_WME));
if (unlikely(psi_arg == NULL))
return EAGAIN;
psi_arg->m_child_key= key;
psi_arg->m_child_identity= (arg ? arg : thread);
psi_arg->m_user_start_routine= start_routine;
psi_arg->m_user_arg= arg;
parent= my_thread_get_THR_PFS();
if (parent != NULL)
{
/*
Make a copy of the parent attributes.
This is required, because instrumentation for this thread (the parent)
may be destroyed before the child thread instrumentation is created.
*/
psi_arg->m_thread_internal_id= parent->m_thread_internal_id;
memcpy(psi_arg->m_username, parent->m_username, sizeof(psi_arg->m_username));
psi_arg->m_username_length= parent->m_username_length;
memcpy(psi_arg->m_hostname, parent->m_hostname, sizeof(psi_arg->m_hostname));
psi_arg->m_hostname_length= parent->m_hostname_length;
}
else
{
psi_arg->m_thread_internal_id= 0;
psi_arg->m_username_length= 0;
psi_arg->m_hostname_length= 0;
}
int result= my_thread_create(thread, attr, pfs_spawn_thread, psi_arg);
if (unlikely(result != 0))
my_free(psi_arg);
return result;
}
注意上面代码中最后的位置： my_thread_create(thread, attr, pfs_spawn_thread, psi_arg);这个函数直接调用pthread_create(&thread->thread, attr, func, arg)创建pthead。
这里最重要的事情是把当前thread的执行环境传到新的thread。所以上面代码前半部分都是在做这个事情。让我们看一下都需要传入哪些上下文。参数psi_arg就是要传入的上下文。开始用my_malloc创建，最后用my_free销毁。中间是对psi_arg进行赋值。
和当前线程有关的是parent= my_thread_get_THR_PFS()。然后把需要的parent内容取出来并赋值给psi_arg：
/* Make a copy of the parent attributes. This is required, because instrumentation for this thread (the parent) may be destroyed before the child thread instrumentation is created. */ psi_arg->m_thread_internal_id= parent->m_thread_internal_id; memcpy(psi_arg->m_username, parent->m_username, sizeof(psi_arg->m_username)); psi_arg->m_username_length= parent->m_username_length; memcpy(psi_arg->m_hostname, parent->m_hostname, sizeof(psi_arg->m_hostname)); psi_arg->m_hostname_length= parent->m_hostname_length;
主要是对三个变量赋值：m_thread_internal_id，m_username，m_hostname。
生成PFS_thread从上面可以看到，生成的thread具体执行的pfs_spawn_thread函数，其内容如下：
extern "C" void* pfs_spawn_thread(void *arg)
{
PFS_spawn_thread_arg *typed_arg= (PFS_spawn_thread_arg*) arg;
void *user_arg;
void *(*user_start_routine)(void*);
PFS_thread *pfs;
/* First, attach instrumentation to this newly created pthread. */
PFS_thread_class *klass= find_thread_class(typed_arg->m_child_key);
if (likely(klass != NULL))
{
pfs= create_thread(klass, typed_arg->m_child_identity, 0);
if (likely(pfs != NULL))
{
pfs->m_thread_os_id= my_thread_os_id();
clear_thread_account(pfs);
pfs->m_parent_thread_internal_id= typed_arg->m_thread_internal_id;
memcpy(pfs->m_username, typed_arg->m_username, sizeof(pfs->m_username));
pfs->m_username_length= typed_arg->m_username_length;
memcpy(pfs->m_hostname, typed_arg->m_hostname, sizeof(pfs->m_hostname));
pfs->m_hostname_length= typed_arg->m_hostname_length;
set_thread_account(pfs);
}
}
else
{
pfs= NULL;
}
std::cout << "my_thread_set_THR_PFS in pfs_spawn_thread, value: " << pfs << std::endl;
my_thread_set_THR_PFS(pfs);
/*
Secondly, free the memory allocated in spawn_thread_v1().
It is preferable to do this before invoking the user
routine, to avoid memory leaks at shutdown, in case
the server exits without waiting for this thread.
*/
user_start_routine= typed_arg->m_user_start_routine;
user_arg= typed_arg->m_user_arg;
my_free(typed_arg);
/* Then, execute the user code for this thread. */
(*user_start_routine)(user_arg);
return NULL;
}
代码改动
由于开发原因，我加入了一个boost线程池，那么从原始线程产生任务塞入boost线程池中的时候，需要做类似的操作，即要传入一个psi_arg参数。因为PSI是performance schema，所以其本身对执行并没有影响，我们可以把子线程的PSI设置为NULL。在psi.h中，我们可以看到：
/** Instrumented thread key. To instrument a thread, a thread key must be obtained using @c register_thread. Using a zero key always disable the instrumentation. */ typedef unsigned int PSI_thread_key;
获取当前的pfs：
/**
Implementation of the thread instrumentation interface.
@sa PSI_v1::get_thread_id.
*/
PSI_thread*
pfs_get_thread_v1(void)
{
PFS_thread *pfs= my_thread_get_THR_PFS();
return reinterpret_cast (pfs);
}
注意，不能直接用my_thread_get_THR_PFS()获取，因为其为static函数，只能用于本文件使用。同理设置pfs：
/**
Implementation of the thread instrumentation interface.
@sa PSI_v1::set_thread.
*/
void pfs_set_thread_v1(PSI_thread* thread)
{
PFS_thread *pfs= reinterpret_cast (thread);
my_thread_set_THR_PFS(pfs);
std::cout << "my_thread_set_THR_PFS in pfs_set_thread_v1, value: "<< pfs << std::endl;
}
附录：
定义的PSI结构（psi.h）:
/**
Performance Schema Interface, version 1.
@since PSI_VERSION_1
*/
struct PSI_v1
{
/** @sa register_mutex_v1_t. */
register_mutex_v1_t register_mutex;
/** @sa register_rwlock_v1_t. */
register_rwlock_v1_t register_rwlock;
/** @sa register_cond_v1_t. */
register_cond_v1_t register_cond;
/** @sa register_thread_v1_t. */
register_thread_v1_t register_thread;
/** @sa register_file_v1_t. */
register_file_v1_t register_file;
/** @sa register_stage_v1_t. */
register_stage_v1_t register_stage;
/** @sa register_statement_v1_t. */
register_statement_v1_t register_statement;
/** @sa register_socket_v1_t. */
register_socket_v1_t register_socket;
/** @sa init_mutex_v1_t. */
init_mutex_v1_t init_mutex;
/** @sa destroy_mutex_v1_t. */
destroy_mutex_v1_t destroy_mutex;
/** @sa init_rwlock_v1_t. */
init_rwlock_v1_t init_rwlock;
/** @sa destroy_rwlock_v1_t. */
destroy_rwlock_v1_t destroy_rwlock;
/** @sa init_cond_v1_t. */
init_cond_v1_t init_cond;
/** @sa destroy_cond_v1_t. */
destroy_cond_v1_t destroy_cond;
/** @sa init_socket_v1_t. */
init_socket_v1_t init_socket;
/** @sa destroy_socket_v1_t. */
destroy_socket_v1_t destroy_socket;
/** @sa get_table_share_v1_t. */
get_table_share_v1_t get_table_share;
/** @sa release_table_share_v1_t. */
release_table_share_v1_t release_table_share;
/** @sa drop_table_share_v1_t. */
drop_table_share_v1_t drop_table_share;
/** @sa open_table_v1_t. */
open_table_v1_t open_table;
/** @sa unbind_table_v1_t. */
unbind_table_v1_t unbind_table;
/** @sa rebind_table_v1_t. */
rebind_table_v1_t rebind_table;
/** @sa close_table_v1_t. */
close_table_v1_t close_table;
/** @sa create_file_v1_t. */
create_file_v1_t create_file;
/** @sa spawn_thread_v1_t. */
spawn_thread_v1_t spawn_thread;
/** @sa new_thread_v1_t. */
new_thread_v1_t new_thread;
/** @sa set_thread_id_v1_t. */
set_thread_id_v1_t set_thread_id;
/** @sa set_thread_THD_v1_t. */
set_thread_THD_v1_t set_thread_THD;
/** @sa set_thread_os_id_v1_t. */
set_thread_os_id_v1_t set_thread_os_id;
/** @sa get_thread_v1_t. */
get_thread_v1_t get_thread;
/** @sa set_thread_user_v1_t. */
set_thread_user_v1_t set_thread_user;
/** @sa set_thread_account_v1_t. */
set_thread_account_v1_t set_thread_account;
/** @sa set_thread_db_v1_t. */
set_thread_db_v1_t set_thread_db;
/** @sa set_thread_command_v1_t. */
set_thread_command_v1_t set_thread_command;
/** @sa set_connection_type_v1_t. */
set_connection_type_v1_t set_connection_type;
/** @sa set_thread_start_time_v1_t. */
set_thread_start_time_v1_t set_thread_start_time;
/** @sa set_thread_state_v1_t. */
set_thread_state_v1_t set_thread_state;
/** @sa set_thread_info_v1_t. */
set_thread_info_v1_t set_thread_info;
/** @sa set_thread_v1_t. */
set_thread_v1_t set_thread;
/** @sa delete_current_thread_v1_t. */
delete_current_thread_v1_t delete_current_thread;
/** @sa delete_thread_v1_t. */
delete_thread_v1_t delete_thread;
/** @sa get_thread_file_name_locker_v1_t. */
get_thread_file_name_locker_v1_t get_thread_file_name_locker;
/** @sa get_thread_file_stream_locker_v1_t. */
get_thread_file_stream_locker_v1_t get_thread_file_stream_locker;
/** @sa get_thread_file_descriptor_locker_v1_t. */
get_thread_file_descriptor_locker_v1_t get_thread_file_descriptor_locker;
/** @sa unlock_mutex_v1_t. */
unlock_mutex_v1_t unlock_mutex;
/** @sa unlock_rwlock_v1_t. */
unlock_rwlock_v1_t unlock_rwlock;
/** @sa signal_cond_v1_t. */
signal_cond_v1_t signal_cond;
/** @sa broadcast_cond_v1_t. */
broadcast_cond_v1_t broadcast_cond;
/** @sa start_idle_wait_v1_t. */
start_idle_wait_v1_t start_idle_wait;
/** @sa end_idle_wait_v1_t. */
end_idle_wait_v1_t end_idle_wait;
/** @sa start_mutex_wait_v1_t. */
start_mutex_wait_v1_t start_mutex_wait;
/** @sa end_mutex_wait_v1_t. */
end_mutex_wait_v1_t end_mutex_wait;
/** @sa start_rwlock_rdwait_v1_t. */
start_rwlock_rdwait_v1_t start_rwlock_rdwait;
/** @sa end_rwlock_rdwait_v1_t. */
end_rwlock_rdwait_v1_t end_rwlock_rdwait;
/** @sa start_rwlock_wrwait_v1_t. */
start_rwlock_wrwait_v1_t start_rwlock_wrwait;
/** @sa end_rwlock_wrwait_v1_t. */
end_rwlock_wrwait_v1_t end_rwlock_wrwait;
/** @sa start_cond_wait_v1_t. */
start_cond_wait_v1_t start_cond_wait;
/** @sa end_cond_wait_v1_t. */
end_cond_wait_v1_t end_cond_wait;
/** @sa start_table_io_wait_v1_t. */
start_table_io_wait_v1_t start_table_io_wait;
/** @sa end_table_io_wait_v1_t. */
end_table_io_wait_v1_t end_table_io_wait;
/** @sa start_table_lock_wait_v1_t. */
start_table_lock_wait_v1_t start_table_lock_wait;
/** @sa end_table_lock_wait_v1_t. */
end_table_lock_wait_v1_t end_table_lock_wait;
/** @sa start_file_open_wait_v1_t. */
start_file_open_wait_v1_t start_file_open_wait;
/** @sa end_file_open_wait_v1_t. */
end_file_open_wait_v1_t end_file_open_wait;
/** @sa end_file_open_wait_and_bind_to_descriptor_v1_t. */
end_file_open_wait_and_bind_to_descriptor_v1_t
end_file_open_wait_and_bind_to_descriptor;
/** @sa end_temp_file_open_wait_and_bind_to_descriptor_v1_t. */
end_temp_file_open_wait_and_bind_to_descriptor_v1_t
end_temp_file_open_wait_and_bind_to_descriptor;
/** @sa start_file_wait_v1_t. */
start_file_wait_v1_t start_file_wait;
/** @sa end_file_wait_v1_t. */
end_file_wait_v1_t end_file_wait;
/** @sa start_file_close_wait_v1_t. */
start_file_close_wait_v1_t start_file_close_wait;
/** @sa end_file_close_wait_v1_t. */
end_file_close_wait_v1_t end_file_close_wait;
/** @sa start_stage_v1_t. */
start_stage_v1_t start_stage;
/** @sa get_current_stage_progress_v1_t. */
get_current_stage_progress_v1_t get_current_stage_progress;
/** @sa end_stage_v1_t. */
end_stage_v1_t end_stage;
/** @sa get_thread_statement_locker_v1_t. */
get_thread_statement_locker_v1_t get_thread_statement_locker;
/** @sa refine_statement_v1_t. */
refine_statement_v1_t refine_statement;
/** @sa start_statement_v1_t. */
start_statement_v1_t start_statement;
/** @sa set_statement_text_v1_t. */
set_statement_text_v1_t set_statement_text;
/** @sa set_statement_lock_time_t. */
set_statement_lock_time_t set_statement_lock_time;
/** @sa set_statement_rows_sent_t. */
set_statement_rows_sent_t set_statement_rows_sent;
/** @sa set_statement_rows_examined_t. */
set_statement_rows_examined_t set_statement_rows_examined;
/** @sa inc_statement_created_tmp_disk_tables. */
inc_statement_created_tmp_disk_tables_t inc_statement_created_tmp_disk_tables;
/** @sa inc_statement_created_tmp_tables. */
inc_statement_created_tmp_tables_t inc_statement_created_tmp_tables;
/** @sa inc_statement_select_full_join. */
inc_statement_select_full_join_t inc_statement_select_full_join;
/** @sa inc_statement_select_full_range_join. */
inc_statement_select_full_range_join_t inc_statement_select_full_range_join;
/** @sa inc_statement_select_range. */
inc_statement_select_range_t inc_statement_select_range;
/** @sa inc_statement_select_range_check. */
inc_statement_select_range_check_t inc_statement_select_range_check;
/** @sa inc_statement_select_scan. */
inc_statement_select_scan_t inc_statement_select_scan;
/** @sa inc_statement_sort_merge_passes. */
inc_statement_sort_merge_passes_t inc_statement_sort_merge_passes;
/** @sa inc_statement_sort_range. */
inc_statement_sort_range_t inc_statement_sort_range;
/** @sa inc_statement_sort_rows. */
inc_statement_sort_rows_t inc_statement_sort_rows;
/** @sa inc_statement_sort_scan. */
inc_statement_sort_scan_t inc_statement_sort_scan;
/** @sa set_statement_no_index_used. */
set_statement_no_index_used_t set_statement_no_index_used;
/** @sa set_statement_no_good_index_used. */
set_statement_no_good_index_used_t set_statement_no_good_index_used;
/** @sa end_statement_v1_t. */
end_statement_v1_t end_statement;
/** @sa get_thread_transaction_locker_v1_t. */
get_thread_transaction_locker_v1_t get_thread_transaction_locker;
/** @sa start_transaction_v1_t. */
start_transaction_v1_t start_transaction;
/** @sa set_transaction_xid_v1_t. */
set_transaction_xid_v1_t set_transaction_xid;
/** @sa set_transaction_xa_state_v1_t. */
set_transaction_xa_state_v1_t set_transaction_xa_state;
/** @sa set_transaction_gtid_v1_t. */
set_transaction_gtid_v1_t set_transaction_gtid;
/** @sa set_transaction_trxid_v1_t. */
set_transaction_trxid_v1_t set_transaction_trxid;
/** @sa inc_transaction_savepoints_v1_t. */
inc_transaction_savepoints_v1_t inc_transaction_savepoints;
/** @sa inc_transaction_rollback_to_savepoint_v1_t. */
inc_transaction_rollback_to_savepoint_v1_t inc_transaction_rollback_to_savepoint;
/** @sa inc_transaction_release_savepoint_v1_t. */
inc_transaction_release_savepoint_v1_t inc_transaction_release_savepoint;
/** @sa end_transaction_v1_t. */
end_transaction_v1_t end_transaction;
/** @sa start_socket_wait_v1_t. */
start_socket_wait_v1_t start_socket_wait;
/** @sa end_socket_wait_v1_t. */
end_socket_wait_v1_t end_socket_wait;
/** @sa set_socket_state_v1_t. */
set_socket_state_v1_t set_socket_state;
/** @sa set_socket_info_v1_t. */
set_socket_info_v1_t set_socket_info;
/** @sa set_socket_thread_owner_v1_t. */
set_socket_thread_owner_v1_t set_socket_thread_owner;
/** @sa create_prepared_stmt_v1_t. */
create_prepared_stmt_v1_t create_prepared_stmt;
/** @sa destroy_prepared_stmt_v1_t. */
destroy_prepared_stmt_v1_t destroy_prepared_stmt;
/** @sa reprepare_prepared_stmt_v1_t. */
reprepare_prepared_stmt_v1_t reprepare_prepared_stmt;
/** @sa execute_prepared_stmt_v1_t. */
execute_prepared_stmt_v1_t execute_prepared_stmt;
/** @sa digest_start_v1_t. */
digest_start_v1_t digest_start;
/** @sa digest_end_v1_t. */
digest_end_v1_t digest_end;
/** @sa set_thread_connect_attrs_v1_t. */
set_thread_connect_attrs_v1_t set_thread_connect_attrs;
/** @sa start_sp_v1_t. */
start_sp_v1_t start_sp;
/** @sa start_sp_v1_t. */
end_sp_v1_t end_sp;
/** @sa drop_sp_v1_t. */
drop_sp_v1_t drop_sp;
/** @sa get_sp_share_v1_t. */
get_sp_share_v1_t get_sp_share;
/** @sa release_sp_share_v1_t. */
release_sp_share_v1_t release_sp_share;
/** @sa register_memory_v1_t. */
register_memory_v1_t register_memory;
/** @sa memory_alloc_v1_t. */
memory_alloc_v1_t memory_alloc;
/** @sa memory_realloc_v1_t. */
memory_realloc_v1_t memory_realloc;
/** @sa memory_claim_v1_t. */
memory_claim_v1_t memory_claim;
/** @sa memory_free_v1_t. */
memory_free_v1_t memory_free;
unlock_table_v1_t unlock_table;
create_metadata_lock_v1_t create_metadata_lock;
set_metadata_lock_status_v1_t set_metadata_lock_status;
destroy_metadata_lock_v1_t destroy_metadata_lock;
start_metadata_wait_v1_t start_metadata_wait;
end_metadata_wait_v1_t end_metadata_wait;
};
该结构在psi.cc被赋值：
/**
Implementation of the instrumentation interface.
@sa PSI_v1.
*/
PSI_v1 PFS_v1=
{
pfs_register_mutex_v1,
pfs_register_rwlock_v1,
pfs_register_cond_v1,
pfs_register_thread_v1,
pfs_register_file_v1,
pfs_register_stage_v1,
pfs_register_statement_v1,
pfs_register_socket_v1,
pfs_init_mutex_v1,
pfs_destroy_mutex_v1,
pfs_init_rwlock_v1,
pfs_destroy_rwlock_v1,
pfs_init_cond_v1,
pfs_destroy_cond_v1,
pfs_init_socket_v1,
pfs_destroy_socket_v1,
pfs_get_table_share_v1,
pfs_release_table_share_v1,
pfs_drop_table_share_v1,
pfs_open_table_v1,
pfs_unbind_table_v1,
pfs_rebind_table_v1,
pfs_close_table_v1,
pfs_create_file_v1,
pfs_spawn_thread_v1,
pfs_new_thread_v1,
pfs_set_thread_id_v1,
pfs_set_thread_THD_v1,
pfs_set_thread_os_id_v1,
pfs_get_thread_v1,
pfs_set_thread_user_v1,
pfs_set_thread_account_v1,
pfs_set_thread_db_v1,
pfs_set_thread_command_v1,
pfs_set_connection_type_v1,
pfs_set_thread_start_time_v1,
pfs_set_thread_state_v1,
pfs_set_thread_info_v1,
pfs_set_thread_v1,
pfs_delete_current_thread_v1,
pfs_delete_thread_v1,
pfs_get_thread_file_name_locker_v1,
pfs_get_thread_file_stream_locker_v1,
pfs_get_thread_file_descriptor_locker_v1,
pfs_unlock_mutex_v1,
pfs_unlock_rwlock_v1,
pfs_signal_cond_v1,
pfs_broadcast_cond_v1,
pfs_start_idle_wait_v1,
pfs_end_idle_wait_v1,
pfs_start_mutex_wait_v1,
pfs_end_mutex_wait_v1,
pfs_start_rwlock_rdwait_v1,
pfs_end_rwlock_rdwait_v1,
pfs_start_rwlock_wrwait_v1,
pfs_end_rwlock_wrwait_v1,
pfs_start_cond_wait_v1,
pfs_end_cond_wait_v1,
pfs_start_table_io_wait_v1,
pfs_end_table_io_wait_v1,
pfs_start_table_lock_wait_v1,
pfs_end_table_lock_wait_v1,
pfs_start_file_open_wait_v1,
pfs_end_file_open_wait_v1,
pfs_end_file_open_wait_and_bind_to_descriptor_v1,
pfs_end_temp_file_open_wait_and_bind_to_descriptor_v1,
pfs_start_file_wait_v1,
pfs_end_file_wait_v1,
pfs_start_file_close_wait_v1,
pfs_end_file_close_wait_v1,
pfs_start_stage_v1,
pfs_get_current_stage_progress_v1,
pfs_end_stage_v1,
pfs_get_thread_statement_locker_v1,
pfs_refine_statement_v1,
pfs_start_statement_v1,
pfs_set_statement_text_v1,
pfs_set_statement_lock_time_v1,
pfs_set_statement_rows_sent_v1,
pfs_set_statement_rows_examined_v1,
pfs_inc_statement_created_tmp_disk_tables_v1,
pfs_inc_statement_created_tmp_tables_v1,
pfs_inc_statement_select_full_join_v1,
pfs_inc_statement_select_full_range_join_v1,
pfs_inc_statement_select_range_v1,
pfs_inc_statement_select_range_check_v1,
pfs_inc_statement_select_scan_v1,
pfs_inc_statement_sort_merge_passes_v1,
pfs_inc_statement_sort_range_v1,
pfs_inc_statement_sort_rows_v1,
pfs_inc_statement_sort_scan_v1,
pfs_set_statement_no_index_used_v1,
pfs_set_statement_no_good_index_used_v1,
pfs_end_statement_v1,
pfs_get_thread_transaction_locker_v1,
pfs_start_transaction_v1,
pfs_set_transaction_xid_v1,
pfs_set_transaction_xa_state_v1,
pfs_set_transaction_gtid_v1,
pfs_set_transaction_trxid_v1,
pfs_inc_transaction_savepoints_v1,
pfs_inc_transaction_rollback_to_savepoint_v1,
pfs_inc_transaction_release_savepoint_v1,
pfs_end_transaction_v1,
pfs_start_socket_wait_v1,
pfs_end_socket_wait_v1,
pfs_set_socket_state_v1,
pfs_set_socket_info_v1,
pfs_set_socket_thread_owner_v1,
pfs_create_prepared_stmt_v1,
pfs_destroy_prepared_stmt_v1,
pfs_reprepare_prepared_stmt_v1,
pfs_execute_prepared_stmt_v1,
pfs_digest_start_v1,
pfs_digest_end_v1,
pfs_set_thread_connect_attrs_v1,
pfs_start_sp_v1,
pfs_end_sp_v1,
pfs_drop_sp_v1,
pfs_get_sp_share_v1,
pfs_release_sp_share_v1,
pfs_register_memory_v1,
pfs_memory_alloc_v1,
pfs_memory_realloc_v1,
pfs_memory_claim_v1,
pfs_memory_free_v1,
pfs_unlock_table_v1,
pfs_create_metadata_lock_v1,
pfs_set_metadata_lock_status_v1,
pfs_destroy_metadata_lock_v1,
pfs_start_metadata_wait_v1,
pfs_end_metadata_wait_v1
};
每一个值都是一个函数。感兴趣的可以去看对应实现。
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