* Implement MADV_DONTNEED: deactivate pages in the specified range,
semantics similar to Solaris's MADV_DONTNEED.
* Add MADV_FREE: free pages and swap resources associated with the
specified range, causing the range to be reloaded from backing
store (vnodes) or zero-fill (anonymous), semantics like FreeBSD's
MADV_FREE and like Digital UNIX's MADV_DONTNEED (isn't it SO GREAT
that madvise(2) isn't standardized!?)
As part of this, move the non-map-modifying advice handling out of
uvm_map_advise(), and into sys_madvise().
As another part, implement general amap cleaning in uvm_map_clean(), and
change uvm_map_clean() to only push dirty pages to disk if PGO_CLEANIT
is set in its flags (and update sys___msync13() accordingly). XXX Add
a patchable global "amap_clean_works", defaulting to 1, which can disable
the amap cleaning code, just in case problems are unearthed; this gives
a developer/user a quick way to recover and send a bug report (e.g. boot
into DDB and change the value).
XXX Still need to implement a real uao_flush().
XXX Need to update the manual page.
With these changes, rebuilding libc will automatically cause the new
malloc(3) to use MADV_FREE to actually release pages and swap resources
when it decides that can be done.
> XXX (in)sanity check. We don't do proper datasize checking
> XXX for anonymous (or private writable) mmap(). However,
> XXX know that if we're trying to allocate more than the amount
> XXX remaining under our current data size limit, _that_ should
> XXX be disallowed.
This is one link on the chain of lossage known as PR#7897. It's
definitely not the right fix, but it's better than nothing.
- rather than treating MAP_COPY like MAP_PRIVATE by sheer virtue of it not
being MAP_SHARED, actually convert the MAP_COPY flag into MAP_PRIVATE.
- return EINVAL if MAP_SHARED and MAP_PRIVATE are both included in flags.
* Provide POSIX 1003.1b mlockall(2) and munlockall(2) system calls.
MCL_CURRENT is presently implemented. MCL_FUTURE is not fully
implemented. Also, the same one-unlock-for-every-lock caveat
currently applies here as it does to mlock(2). This will be
addressed in a future commit.
* Provide the mincore(2) system call, with the same semantics as
Solaris.
* Clean up the error recovery in uvm_map_pageable().
* Fix a bug where a process would hang if attempting to mlock a
zero-fill region where none of the pages in that region are resident.
[ This fix has been submitted for inclusion in 1.4.1 ]
offset and size of the requested region to be mapped, so that the
udv_attach() can use the device d_mmap() entry to check mappability
of the requested region.
write protection. this stops data corruption where it was possible
to change the in-memory copy of an append-only file (but not the on-disk
copy). this is documented in NetBSD security advisory 1998-003. thanks
to darrenr, lukem, cgd, mycroft and mrg for this.
the SPARC.
Remove the #ifdef COMPAT_13 for automatically adding a sharing type, since the
interface is *supposed* to support this.
Also modify the DIAGNOSTIC messages here a bit.
UVM was written by chuck cranor <chuck@maria.wustl.edu>, with some
minor portions derived from the old Mach code. i provided some help
getting swap and paging working, and other bug fixes/ideas. chuck
silvers <chuq@chuq.com> also provided some other fixes.
this is the UVM kernel code portion.
this will be KNF'd shortly. :-)
thorpej