NAME

       PR_SET_IO_FLUSHER - change the IO_FLUSHER state

LIBRARY

       Standard C library (libc, -lc)

SYNOPSIS

       #include <linux/prctl.h>  /* Definition of PR_* constants */
       #include <sys/prctl.h>

       int prctl(PR_SET_IO_FLUSHER, long state, 0L, 0L, 0L);

DESCRIPTION

       If  a  user  process is involved in the block layer or filesystem I/O path, and can allocate memory while
       processing I/O requests it must set state to 1.  This will put the process in the IO_FLUSHER state, which
       allows it special treatment to make progress when allocating memory.  If state is  0,  the  process  will
       clear the IO_FLUSHER state, and the default behavior will be used.

       The calling process must have the CAP_SYS_RESOURCE capability.

       The  IO_FLUSHER  state  is  inherited  by  a  child  process  created via fork(2) and is preserved across
       execve(2).

       Examples of IO_FLUSHER applications are FUSE daemons, SCSI device emulation  daemons,  and  daemons  that
       perform error handling like multipath path recovery applications.

RETURN VALUE

       On success, 0 is returned.  On error, -1 is returned, and errno is set to indicate the error.

ERRORS

       EINVAL state is not a valid value.

STANDARDS

       Linux.

HISTORY

       Linux 5.6.

SEE ALSO

       prctl(2), PR_GET_IO_FLUSHER(2const)

Linux man-pages 6.9.1                              2024-06-01                          PR_SET_IO_FLUSHER(2const)