PR_SET_IO_FLUSHER2const
Change the io_flusher state
Usage
#include <linux/prctl.h> /* Definition of PR_* constants */ #include <sys/prctl.h>
int prctl(PR_SET_IO_FLUSHER, long state, 0L, 0L, 0L);
Library
Standard C library (libc, -lc)
Overview
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.
Releases
2 releases since Debian 13 (Trixie); the text changed 1 time.