LDP
/
man-pages
mirror of https://github.com/mkerrisk/man-pages
0
1
Fork 0
Code Releases Activity

prctl.2: Sort prctls into alphabetical order 

The prctl list has historically been sorted by prctl name (ignoring
any SET_ or GET_ prefix) to make individual prctls easier to find.
Some noise seems to have crept in since.

Sort the list back into order.  Similarly, reorder the list of
prctls specified to return non-zero values on success.

Content movement only.  No semantic change.

Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
This commit is contained in:
Dave Martin 2020-05-12 17:36:50 +01:00 committed by Michael Kerrisk
parent 667eb3ac39
commit 194ccff9cc
1 changed files with 70 additions and 70 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

140
man2/prctl.2
View File

@ -490,6 +490,52 @@ Pass \fBPR_FP_EXC_SW_ENABLE\fP to use FPEXC for FP exception enables,
Return floating-point exception mode,
in the location pointed to by
.IR "(int\ *) arg2" .
.\" prctl PR_SET_IO_FLUSHER
.TP
.BR PR_SET_IO_FLUSHER " (since Linux 5.6)"
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
\fIarg2\fP to 1.
This will put the process in the IO_FLUSHER state,
which allows it special treatment to make progress when allocating memory.
If \fIarg2\fP is 0, the process will clear the IO_FLUSHER state, and
the default behavior will be used.
.IP
The calling process must have the
.BR CAP_SYS_RESOURCE
capability.
.IP
.IR arg3 ,
.IR arg4 ,
and
.IR arg5
must be zero.
.IP
The IO_FLUSHER state is inherited by a child process created via
.BR fork (2)
and is preserved across
.BR execve (2).
.IP
Examples of IO_FLUSHER applications are FUSE daemons, SCSI device
emulation daemons, and daemons that perform error handling like multipath
path recovery applications.
.\" prctl PR_GET_IO_FLUSHER
.TP
.B PR_GET_IO_FLUSHER (Since Linux 5.6)
Return (as the function result) the IO_FLUSHER state of the caller.
A value of 1 indicates that the caller is in the IO_FLUSHER state;
0 indicates that the caller is not in the IO_FLUSHER state.
.IP
The calling process must have the
.BR CAP_SYS_RESOURCE
capability.
.IP
.IR arg2 ,
.IR arg3 ,
.IR arg4 ,
and
.IR arg5
must be zero.
.\" prctl PR_SET_KEEPCAPS
.TP
.BR PR_SET_KEEPCAPS " (since Linux 2.2.18)"
@ -1207,23 +1253,6 @@ call failing with the error
.BR ENXIO .
For further details, see the kernel source file
.IR Documentation/admin-guide/kernel-parameters.txt .
.\" prctl PR_SET_THP_DISABLE
.TP
.BR PR_SET_THP_DISABLE " (since Linux 3.15)"
.\" commit a0715cc22601e8830ace98366c0c2bd8da52af52
Set the state of the "THP disable" flag for the calling thread.
If
.I arg2
has a nonzero value, the flag is set, otherwise it is cleared.
Setting this flag provides a method
for disabling transparent huge pages
for jobs where the code cannot be modified, and using a malloc hook with
.BR madvise (2)
is not an option (i.e., statically allocated data).
The setting of the "THP disable" flag is inherited by a child created via
.BR fork (2)
and is preserved across
.BR execve (2).
.\"
.\" prctl PR_TASK_PERF_EVENTS_DISABLE
.TP
@ -1256,6 +1285,23 @@ renamed
.\" commit cdd6c482c9ff9c55475ee7392ec8f672eddb7be6
in Linux 2.6.32.
.\"
.\" prctl PR_SET_THP_DISABLE
.TP
.BR PR_SET_THP_DISABLE " (since Linux 3.15)"
.\" commit a0715cc22601e8830ace98366c0c2bd8da52af52
Set the state of the "THP disable" flag for the calling thread.
If
.I arg2
has a nonzero value, the flag is set, otherwise it is cleared.
Setting this flag provides a method
for disabling transparent huge pages
for jobs where the code cannot be modified, and using a malloc hook with
.BR madvise (2)
is not an option (i.e., statically allocated data).
The setting of the "THP disable" flag is inherited by a child created via
.BR fork (2)
and is preserved across
.BR execve (2).
.\" prctl PR_GET_THP_DISABLE
.TP
.BR PR_GET_THP_DISABLE " (since Linux 3.15)"
@ -1438,67 +1484,21 @@ system call on Tru64).
for information on versions and architectures.)
Return unaligned access control bits, in the location pointed to by
.IR "(unsigned int\ *) arg2" .
.\" prctl PR_SET_IO_FLUSHER
.TP
.BR PR_SET_IO_FLUSHER " (since Linux 5.6)"
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
\fIarg2\fP to 1.
This will put the process in the IO_FLUSHER state,
which allows it special treatment to make progress when allocating memory.
If \fIarg2\fP is 0, the process will clear the IO_FLUSHER state, and
the default behavior will be used.
.IP
The calling process must have the
.BR CAP_SYS_RESOURCE
capability.
.IP
.IR arg3 ,
.IR arg4 ,
and
.IR arg5
must be zero.
.IP
The IO_FLUSHER state is inherited by a child process created via
.BR fork (2)
and is preserved across
.BR execve (2).
.IP
Examples of IO_FLUSHER applications are FUSE daemons, SCSI device
emulation daemons, and daemons that perform error handling like multipath
path recovery applications.
.\" prctl PR_GET_IO_FLUSHER
.TP
.B PR_GET_IO_FLUSHER (Since Linux 5.6)
Return (as the function result) the IO_FLUSHER state of the caller.
A value of 1 indicates that the caller is in the IO_FLUSHER state;
0 indicates that the caller is not in the IO_FLUSHER state.
.IP
The calling process must have the
.BR CAP_SYS_RESOURCE
capability.
.IP
.IR arg2 ,
.IR arg3 ,
.IR arg4 ,
and
.IR arg5
must be zero.
.SH RETURN VALUE
On success,
.BR PR_CAP_AMBIENT + PR_CAP_AMBIENT_IS_SET ,
.BR PR_CAPBSET_READ ,
.BR PR_GET_DUMPABLE ,
.BR PR_GET_FP_MODE ,
.BR PR_GET_IO_FLUSHER ,
.BR PR_GET_KEEPCAPS ,
.BR PR_MCE_KILL_GET ,
.BR PR_GET_NO_NEW_PRIVS ,
.BR PR_GET_THP_DISABLE ,
.BR PR_CAPBSET_READ ,
.BR PR_GET_TIMING ,
.BR PR_GET_TIMERSLACK ,
.BR PR_GET_SECUREBITS ,
.BR PR_GET_SPECULATION_CTRL ,
.BR PR_MCE_KILL_GET ,
.BR PR_CAP_AMBIENT + PR_CAP_AMBIENT_IS_SET ,
.BR PR_GET_IO_FLUSHER ,
.BR PR_GET_THP_DISABLE ,
.BR PR_GET_TIMING ,
.BR PR_GET_TIMERSLACK ,
and (if it returns)
.BR PR_GET_SECCOMP
return the nonnegative values described above.