bdflush — start, flush, or tune buffer-dirty-flush daemon
#include <sys/kdaemon.h>
int
bdflush( |
int func, |
long *address); |
int
bdflush( |
int func, |
long data); |
bdflush() starts, flushes,
or tunes the buffer-dirty-flush daemon. Only a privileged
process (one with the CAP_SYS_ADMIN capability) may call
bdflush().
If func is
negative or 0, and no daemon has been started, then
bdflush() enters the daemon
code and never returns.
If func is 1, some
dirty buffers are written to disk.
If func is 2 or
more and is even (low bit is 0), then address is the address of a
long word, and the tuning parameter numbered (func−2)/2 is returned to
the caller in that address.
If func is 3 or
more and is odd (low bit is 1), then data is a long word, and the
kernel sets tuning parameter numbered (func−3)/2 to that
value.
The set of parameters, their values, and their valid
ranges are defined in the kernel source file fs/buffer.c.
If func is
negative or 0 and the daemon successfully starts,
bdflush() never returns.
Otherwise, the return value is 0 on success and −1 on
failure, with errno set to
indicate the error.
An attempt was made to enter the daemon code after another process has already entered.
address
points outside your accessible address space.
An attempt was made to read or write an invalid parameter number, or to write an invalid value to a parameter.
Caller does not have the CAP_SYS_ADMIN capability.
bdflush() is Linux-specific
and should not be used in programs intended to be
portable.
This page is part of release 3.33 of the Linux man-pages project. A
description of the project, and information about reporting
bugs, can be found at http://man7.org/linux/man-pages/.
|
Copyright (c) 1995 Michael Chastain (mecshell.portal.com), 15 April 1995. This is free documentation; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. The GNU General Public License's references to "object code" and "executables" are to be interpreted as the output of any document formatting or typesetting system, including intermediate and printed output. This manual is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this manual; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA. Modified 1997-01-31 by Eric S. Raymond <esrthyrsus.com> Modified 2004-06-17 by Michael Kerrisk <mtk.manpagesgmail.com> |