.TH SEGFLUSH 2
.SH NAME
segflush \- flush instruction and data caches
.SH SYNOPSIS
.B #include <u.h>
.br
.B #include <libc.h>
.PP
.B
int	segflush(void *va, ulong len)
.PP
.SH DESCRIPTION
.I Segflush
invalidates any instruction cache and writes back any data
cache associated with pages contained in a segment.
All subsequent new pages in the segment will also be flushed when first referenced.
.PP
.I Va
is an address within the segment to be flushed;
it is rounded down to the nearest page boundary.
.I Len
specifies the length in bytes of
the memory to flush;
.IB va + len
is rounded up to the nearest page boundary.
.I Segflush
works correctly when the memory straddles multiple segments.
.PP
Correct use of
.I segflush
depends on an understanding of the cache architecture of the specific
machine.
.SH SOURCE
.B /sys/src/libc/9syscall
.SH SEE ALSO
.IR segattach (2),
.IR segbrk (2)
.br
.BR /proc/*/segment
.SH DIAGNOSTICS
Sets
.IR errstr .