libc: Purge unneeded cdefs.h

These sys/cdefs.h are not needed. Purge them. They are mostly left-over
from the $FreeBSD$ removal. A few in libc are still required for macros
that cdefs.h defines. Kee

libc: Purge unneeded cdefs.h

These sys/cdefs.h are not needed. Purge them. They are mostly left-over
from the $FreeBSD$ removal. A few in libc are still required for macros
that cdefs.h defines. Keep those.

Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D42385

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Remove $FreeBSD$: one-line .c pattern

Remove /^[\s*]*__FBSDID\("\$FreeBSD\$"\);?\s*\n/

MFHead @348740

Sponsored by: The FreeBSD Foundation

Provide separate accounting for user-wired pages.

Historically we have not distinguished between kernel wirings and user
wirings for accounting purposes. User wirings (via mlock(2)) were
subject to

Provide separate accounting for user-wired pages.

Historically we have not distinguished between kernel wirings and user
wirings for accounting purposes. User wirings (via mlock(2)) were
subject to a global limit on the number of wired pages, so if large
swaths of physical memory were wired by the kernel, as happens with
the ZFS ARC among other things, the limit could be exceeded, causing
user wirings to fail.

The change adds a new counter, v_user_wire_count, which counts the
number of virtual pages wired by user processes via mlock(2) and
mlockall(2). Only user-wired pages are subject to the system-wide
limit which helps provide some safety against deadlocks. In
particular, while sources of kernel wirings typically support some
backpressure mechanism, there is no way to reclaim user-wired pages
shorting of killing the wiring process. The limit is exported as
vm.max_user_wired, renamed from vm.max_wired, and changed from u_int
to u_long.

The choice to count virtual user-wired pages rather than physical
pages was done for simplicity. There are mechanisms that can cause
user-wired mappings to be destroyed while maintaining a wiring of
the backing physical page; these make it difficult to accurately
track user wirings at the physical page layer.

The change also closes some holes which allowed user wirings to succeed
even when they would cause the system limit to be exceeded. For
instance, mmap() may now fail with ENOMEM in a process that has called
mlockall(MCL_FUTURE) if the new mapping would cause the user wiring
limit to be exceeded.

Note that bhyve -S is subject to the user wiring limit, which defaults
to 1/3 of physical RAM. Users that wish to exceed the limit must tune
vm.max_user_wired.

Reviewed by: kib, ngie (mlock() test changes)
Tested by: pho (earlier version)
MFC after: 45 days
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D19908

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style(9): sort the #includes

MFC after: 1 week
Sponsored by: Dell EMC Isilon

Merge ^/head r309263 through r309518.

Fix setrlimit_test:setrlimit_memlock when the system has exceeded vm.max_wired.

This uses the same fix as r294894 did for the mlock test. The code from
that commit is moved into a common object fil

Fix setrlimit_test:setrlimit_memlock when the system has exceeded vm.max_wired.

This uses the same fix as r294894 did for the mlock test. The code from
that commit is moved into a common object file which PROGS supports
building first.

Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D8689

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