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HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | STANDARDS | HISTORY | SEE ALSO | COLOPHON |
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bdflush(2) System Calls Manual bdflush(2)
bdflush - start, flush, or tune buffer-dirty-flush daemon
#include <sys/kdaemon.h>
[[deprecated]] int bdflush(int func, long *address);
[[deprecated]] int bdflush(int func, long data);
Note: Since Linux 2.6, this system call is deprecated and does
nothing. It is likely to disappear altogether in a future kernel
release. Nowadays, the task performed by bdflush() is handled by
the kernel pdflush thread.
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 Linux 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.
EBUSY An attempt was made to enter the daemon code after another
process has already entered.
EFAULT address points outside your accessible address space.
EINVAL An attempt was made to read or write an invalid parameter
number, or to write an invalid value to a parameter.
EPERM Caller does not have the CAP_SYS_ADMIN capability.
Linux.
Since glibc 2.23, glibc no longer supports this obsolete system
call.
sync(1), fsync(2), sync(2)
This page is part of the man-pages (Linux kernel and C library
user-space interface documentation) project. Information about
the project can be found at
⟨https://www.kernel.org/doc/man-pages/⟩. If you have a bug report
for this manual page, see
⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩.
This page was obtained from the tarball man-pages-6.9.1.tar.gz
fetched from
⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on
2024-06-26. If you discover any rendering problems in this HTML
version of the page, or you believe there is a better or more up-
to-date source for the page, or you have corrections or
improvements to the information in this COLOPHON (which is not
part of the original manual page), send a mail to
man-pages@man7.org
Linux man-pages 6.9.1 2024-05-02 bdflush(2)
Pages that refer to this page: fsync(2), syscalls(2), capabilities(7)
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HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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