Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

libkvm code janitoring

- make WARNS=6 clean for archs w/o strict alignment requirments
- add const, ANSIfy, remove unused vars, cast types for comparison
- thanks to differing definitions of VM_MIN_ADDRESS across our archs, we
need to trick the compiler to not complain about signedness. We could
either fix VM_MIN_ADDRESS to always be a simple integer or make the
check conditional on $ARCH.

Closes PRs: kern/42386, kern/83364
Reviewed by: bde

- Move 'struct swdevt' back into swap_pager.h and expose it to userland.
- Restore support for fetching swap information from crash dumps via
kvm_get_swapinfo(3) to fix pstat -T/-s on crash dumps.

Reviewed by: arch@, phk
MFC after: 1 week

Expand the license referenced indirectly inline.

Remove various unused variables, prototypes and local variables.

Disable and lobotomize the kvm image reading swapinfo code, the kernel
layout is about to change.

The sysctl based method still returns correct information.

Retire the SWIF_DUMP_TREE code, this is in the way for a rework of
the swap_pager layout.

Unifdef -UDEBUG_SWAPINFO The kernel data structures are about to change.

Remove all use of the LOG2() macro/inline, undoing some non-optimal cruft
that crept in recently. GCC will optimize the divides and multiplies for us.

Submitted by: David Schultz <dschultz@uclink.Berkeley.EDU>
MFC after: 1 day

Make struct swblock kernel only, to make vm/swap_pager.h userland includable.
Move struct swdevt from sys/conf.h to the more appropriate vm/swap_pager.h.
Adjust #include use in libkvm and pstat(8) to match.

Compensate for "Compensate for header dethreading" by backing it out.

Implement __FBSDID()

Change this to support the new way swap device information is exported
via sysctl, and clean up some style and (size_t != int) issues.

Compensate for header dethreading.

Adapt libkvm_getswapinfo() to make use of recently committed vm and swap
sysctls exporting swap information. When running on a live kernel,
the sysctl's will now be used instead of kvm_read, allowing consumers of
this interface to run without privilege (setgid kmem). Retain the
ability to run on coredumps, or on a kernel using kmem if explicitly
pointed at one.

A side effect of this change is that kvm_getswapinfo() is faster now in
the general case. If the SWIF_DUMP_TREE flag is given (pstat -ss does
this), the radix tree walker, which still uses kvm_read in any case, is
invoked, and therefore does require privilege.

Submitted by: Thomas Moestl <tmoestl@gmx.net>
Reviewed by: freebsd-audit

Add `_PATH_DEVZERO'.
Use _PATH_* where where possible.

remove unneded sys/ucred.h include

Remove unneeded #include

-Wall, which caught a real bug where buflen wasn't being set properly.

Use kldsym(2) to lookup symbol values. This avoids the kvm_mkdb juggling
and is module aware. Yes, this means that kvm_nlist(3) will find symbols
in loaded modules. The emulation of the nlist struct is pretty crude but
seems to work well enough for all the users in the tree that I found.

Report swapdevices as cdevs rather than bdevs.

Remove unused dev2budev() function.

$Id$ -> $FreeBSD$

Tidy up references to <sys/rlist.h> and support for the old swap management
that went away in January.

From rev. 1.12 of usr.sbin/pstat/pstat.c by phk:
Reflect the fact that we do not swap on the first <dmmax> blocks of a
swapdev, to protect disklabels and other such magic stuff.

Handle case where no swap is configured

Removed evil typedef kvm_swap_t and all uses of it (not many).

Hoped for by: wollman

Fix swap radix tree dump formatting ( pstat -ss ), it was printing the
wrong radix for recursive subnodes.

Add SWIF_DEV_PREFIX flag to add "/dev/..." to device name.

Implement kvm_getswapinfo() libkvm function. Will be used by
pstat, top, and systat.