from mysql-5.7.6-m16/storage/innobase/buf/buf0flu.cc

gistfile1.txt

2942 #ifdef UNIV_LINUX
2943         /* linux might be able to set different setting for each thread.
2944         worth to try to set high priority for page cleaner threads */
2945         if (buf_flush_page_cleaner_set_priority(
2946                 buf_flush_page_cleaner_priority)) {
2947
2948                 ib::info() << "page_cleaner coordinator priority: "
2949                         << buf_flush_page_cleaner_priority;
2950         } else {
2951                 ib::info() << "If the mysqld execution user is authorized,"
2952                 " page cleaner thread priority can be changed."
2953                 " See the man page of setpriority().";
2954         }
2955 #endif /* UNIV_LINUX */


2900 /**
2901 Set priority for page_cleaner threads.
2902 @param[in]      priority        priority intended to set
2903 @return true if set as intended */
2904 static
2905 bool
2906 buf_flush_page_cleaner_set_priority(
2907         int     priority)
2908 {
2909         setpriority(PRIO_PROCESS, (pid_t)syscall(SYS_gettid),
2910                     priority);
2911         return(getpriority(PRIO_PROCESS, (pid_t)syscall(SYS_gettid))
2912                == priority);
2913 }