MFC r332816: call racct_proc_ucred_changed() under the proc lock

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

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

sys/kern: spelling fixes in comments.

No functional change.

Get rid of rctl_lock; use racct_lock where appropriate. The fast paths
already required both of them, so having a separate rctl_lock didn't
buy us anything.

Reviewed by: mjg@
MFC after: 1 month
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D5914

kern_rctl: Fix resource leak in error path

Ordinarily, rctl_write_outbuf frees 'sb'. However, if we are in low memory
conditions we skip past the rctl_write_outbuf. In that case, free 'sb'.

Reported by: Coverity
CID: 1338539
Sponsored by: EMC / Isilon Storage Division

Fix debugging printf.

MFC after: 1 month
Sponsored by: The FreeBSD Foundation

Allocate RACCT/RCTL zones without UMA_ZONE_NOFREE; no idea why it was there
in the first place.

MFC after: 1 month
Sponsored by: The FreeBSD Foundation

Sort variable declarations.

MFC after: 1 month
Sponsored by: The FreeBSD Foundation

Fix overflow checking.

There are some other potential problems related to overflowing racct
counters; I'll revisit those later.

Submitted by: Pieter de Goeje (earlier version)
Reviewed by: emaste@
MFC after: 1 month
Sponsored by: The FreeBSD Foundation

Make it possible to tweak RCTL throttling sysctls at runtime.

MFC after: 1 month
Sponsored by: The FreeBSD Foundation

Add four new RCTL resources - readbps, readiops, writebps and writeiops,
for limiting disk (actually filesystem) IO.

Note that in some cases these limits are not quite precise. It's ok,
as long as it's within some reasonable bounds.

Testing - and review of the code, in particular the VFS and VM parts - is
very welcome.

MFC after: 1 month
Relnotes: yes
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D5080

Use proper locking macros in RACCT in RCTL.

MFC after: 1 month
Sponsored by: The FreeBSD Foundation

Add configurable rate limit for "log" and "devctl" actions.

MFC after: 1 month
Sponsored by: The FreeBSD Foundation

Refactor; no functional changes.

MFC after: 1 month
Sponsored by: The FreeBSD Foundation

Fix overflows, making it impossible to add negative amounts using rctl(8).

MFC after: 1 month
Sponsored by: The FreeBSD Foundation

Fix the way RCTL handles rules' rrl_exceeded on credenials change.
Because of what this variable does, it was probably harmless - but
still incorrect.

MFC after: 1 month
Sponsored by: The FreeBSD Foundation

Tweak comments.

MFC after: 1 month
Sponsored by: The FreeBSD Foundation

Speed up rctl operation with large rulesets, by holding the lock
during iteration instead of relocking it for each traversed rule.

Reviewed by: mjg@
MFC after: 1 month
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D4110

Make naming more consistent; no functional changes.

MFC after: 1 month
Sponsored by: The FreeBSD Foundation

Speed up rctl(8) rule retrieval; the difference shows mostly in "rctl -n",
as otherwise most of the time is spent resolving UIDs to names.

Reviewed by: mjg@
MFC after: 1 month
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D4059

Add kern.racct.enable tunable and RACCT_DISABLED config option.
The point of this is to be able to add RACCT (with RACCT_DISABLED)
to GENERIC, to avoid having to rebuild the kernel to use rctl(8).

Differential Revision: https://reviews.freebsd.org/D2369
Reviewed by: kib@
MFC after: 1 month
Relnotes: yes
Sponsored by: The FreeBSD Foundation

Add CPU percentage limit enforcement to RCTL. The resouce name is "pcpu".
It was implemented by Rudolf Tomori during Google Summer of Code 2012.

Stop treating system processes as special. This fixes panics
like the one triggered by this:

# kldload geom_vinum
# pwait `pgrep -S gv_worker` &
# kldunload geom_vinum

or this:

GEOM_JOURNAL: Shutting down geom gjournal 3464572051.
panic: destroying non-empty racct: 1 allocated for resource 6

which were tracked by jh@ to be caused by checking p->p_flag,
while it wasn't initialised yet. Basically, during fork, the code
checked p_flag, concluded the process isn't marked as P_SYSTEM,
incremented the counter, and later on, when exiting, checked that
the process was marked as P_SYSTEM, and thus didn't decrement it.

Also, I believe there wasn't any good reason for checking P_SYSTEM
in the first place.

Tested by: jh

Enforce upper bound on the input buffer length.

Reported by: Mateusz Guzik

Mark MALLOC_DEFINEs static that have no corresponding MALLOC_DECLAREs.

This means that their use is restricted to a single C file.

Fix another bug introduced in r225641, which caused rctl to access certain
fields in 'struct proc' before they got initialized in do_fork().

MFC after: 3 days

In order to maximize the re-usability of kernel code in user space this
patch modifies makesyscalls.sh to prefix all of the non-compatibility
calls (e.g. not linux_, freebsd32_) with sys_ and updates the kernel
entry points and all places in the code that use them. It also
fixes an additional name space collision between the kernel function
psignal and the libc function of the same name by renaming the kernel
psignal kern_psignal(). By introducing this change now we will ease future
MFCs that change syscalls.

Reviewed by: rwatson
Approved by: re (bz)

Fix whitespace.

Submitted by: amdmi3
Approved by: re (rwatson)

Work around a kernel panic triggered by forkbomb with an rctl rule
such as j:name:maxproc:sigkill=100. Proper fix - deferring psignal
to a taskqueue - is somewhat complicated and thus will happen
after 9.0.

Approved by: re (kib)

Since r224036 the cputime and wallclock are supposed to be in seconds,
not microseconds. Make it so.

Approved by: re (kib)

Rename resource names to match these in login.conf.

Style fix - macros are supposed to be uppercase.

Remove definitions for RACCT_FSIZE and RACCT_SBSIZE - these two are rather
performance-sensitive and not that useful, so I won't be merging them
before 9.0.

Change the way rctl interfaces with jails by introducing prison_racct
structure, which acts as a proxy between them. This makes jail rules
persistent, i.e. they can be added before jail gets created, and they
don't disappear when the jail gets destroyed.

Rename a misnamed structure field (hr_loginclass), and reorder priv(9)
constants to match the order and naming of syscalls. No functional changes.

Add rctl. It's used by racct to take user-configurable actions based
on the set of rules it maintains and the current resource usage. It also
privides userland API to manage that ruleset.

Sponsored by: The FreeBSD Foundation
Reviewed by: kib (earlier version)