PR_SET_IO_FLUSHER(2const) — Linux manual page

PR_SET_IO_FLUSHER(2const)                      PR_SET_IO_FLUSHER(2const)

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)

COLOPHON

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

Pages that refer to this page: prctl(2), PR_GET_IO_FLUSHER(2const)

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