madvise().
This feature prevents the update daemon from gratuitously flushing
dirty pages associated with a mapped file-backed region of memory. The
system pager will still page the memory as necessary and the VM system
will still be fully coherent with the filesystem. Modifications made
by other means to the same area of memory, for example by write(), are
unaffected. The feature works on a page-granularity basis.
MAP_NOSYNC allows one to use mmap() to share memory between processes
without incuring any significant filesystem overhead, putting it in
the same performance category as SysV Shared memory and anonymous memory.
Reviewed by: julian, alc, dg
track.
The $Id$ line is normally at the bottom of the main comment block in the
man page, separated from the rest of the manpage by an empty comment,
like so;
.\" $Id$
.\"
If the immediately preceding comment is a @(#) format ID marker than the
the $Id$ will line up underneath it with no intervening blank lines.
Otherwise, an additional blank line is inserted.
Approved by: bde
This changes the definitions of a few items so that structures are the
same whether or not the option itself is enabled. This allows
people to enable and disable the option without recompilng the world.
As the author says:
|I ran into a problem pulling out the VM_STACK option. I was aware of this
|when I first did the work, but then forgot about it. The VM_STACK stuff
|has some code changes in the i386 branch. There need to be corresponding
|changes in the alpha branch before it can come out completely.
what is done:
|
|1) Pull the VM_STACK option out of the header files it appears in. This
|really shouldn't affect anything that executes with or without the rest
|of the VM_STACK patches. The vm_map_entry will then always have one
|extra element (avail_ssize). It just won't be used if the VM_STACK
|option is not turned on.
|
|I've also pulled the option out of vm_map.c. This shouldn't harm anything,
|since the routines that are enabled as a result are not called unless
|the VM_STACK option is enabled elsewhere.
|
|2) Add what appears to be appropriate code the the alpha branch, still
|protected behind the VM_STACK switch. I don't have an alpha machine,
|so we would need to get some testers with alpha machines to try it out.
|
|Once there is some testing, we can consider making the change permanent
|for both i386 and alpha.
|
[..]
|
|Once the alpha code is adequately tested, we can pull VM_STACK out
|everywhere.
|
Submitted by: "Richard Seaman, Jr." <dick@tar.com>
mlock, mmap, mprotect, msync, munlock, and munmap are defined by
POSIX as taking void *. The const modifier has been added to
mlock, munlock, and mprotect as the standard dictates.
minherit comes from OpenBSD and has been updated to conform with
their recent change to void *.
madvise and mincore are not defined by POSIX, but their arguments
have been modified to be consistent with the POSIX-defined functions.
mincore takes a const pointer, but madvise does not due to the
MADV_FREE case.
Discussed with: bde
in a bunch of man pages.
Use the correct .Bx (BSD UNIX) or .At (AT&T UNIX) macros
instead of explicitly specifying the version in the text
in a bunch of man pages.
in the main text of various man pages.
Thanks to Warner Losh for adding an option to manck to allow
it to scan the entire man page looking for bogus xrefs, instead
of just checking the SEE ALSO section.
