bdflush(2) System Calls Manual bdflush(2)

bdflush - start, flush, or tune buffer-dirty-flush daemon

#include <sys/kdaemon.h>
int bdflush(int func, long data);

This system call used to turn the calling process into the bdflush daemon, or tune it, or flush the "old buffers". It then progressively lost all of that functionality.

See fs/buffer.c in the kernel version you're interested in to see what it actually does there.

ENOSYS (this system call is unimplemented)

Linux.

This system call was introduced in Linux 1.1.3, became effectively obsolete in Linux 1.3.50, mostly useless in Linux 2.3.23, entirely useless in Linux 2.5.12, officially deprecated in Linux 2.5.52, and removed outright in Linux 5.15.

Sometimes, if func was even, data actually represented a pointer.

The header and prototype were removed in glibc 2.23.

sync(1), fsync(2), sync(2)

2024-08-21 Linux man-pages 6.13