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 be-
havior 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 emula-
tion 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)
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