sys/queue.h: Add {LIST,TAILQ}_REPLACE().

MFC after: 1 week
Obtained from: NetBSD
Sponsored by: Klara, Inc.
Reviewed by: cperciva, imp
Differential Revision: https://reviews.freebsd.org/D44679

sys/queue.h: Whitespace cleanup.

MFC after: 1 week
Sponsored by: Klara, Inc.
Differential Revision: https://reviews.freebsd.org/D44678

sys: Remove ancient SCCS tags.

Remove ancient SCCS tags from the tree, automated scripting, with two
minor fixup to keep things compiling. All the common forms in the tree
were removed with a perl s

sys: Remove ancient SCCS tags.

Remove ancient SCCS tags from the tree, automated scripting, with two
minor fixup to keep things compiling. All the common forms in the tree
were removed with a perl script.

Sponsored by: Netflix

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queue.h: Define {LIST,TAILQ}_REMOVE_HEAD

The LIST and TAILQ structures have fast _REMOVE macros (since each
element has a pointer to the previous element); we implement the
_REMOVE_HEAD macros for t

queue.h: Define {LIST,TAILQ}_REMOVE_HEAD

The LIST and TAILQ structures have fast _REMOVE macros (since each
element has a pointer to the previous element); we implement the
_REMOVE_HEAD macros for them by simply finding the first element and
then removing it.

Reviewed by: jhb, emaste
Sponsored by: https://www.patreon.com/cperciva
Differential Revision: https://reviews.freebsd.org/D41072

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sys: Remove $FreeBSD$: one-line .h pattern

Remove /^\s*\*+\s*\$FreeBSD\$.*$\n/

sys/queue.h: move trashing from SLIST_REMOVE to REMOVE_AFTER, REMOVE_HEAD

SLIST_REMOVE calls either REMOVE_AFTER or REMOVE_HEAD to do the job.
But those two macros can be used independently as well.

sys/queue.h: move trashing from SLIST_REMOVE to REMOVE_AFTER, REMOVE_HEAD

SLIST_REMOVE calls either REMOVE_AFTER or REMOVE_HEAD to do the job.
But those two macros can be used independently as well.

MFC after: 2 weeks

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qeueue.h: Add {SLIST,STAILQ,LIST,TAILQ}_END()

We provide these for compat with other queue.h headers since some software
assumes it exists (e.g. the libevent contrib code), but we are not
encouragin

qeueue.h: Add {SLIST,STAILQ,LIST,TAILQ}_END()

We provide these for compat with other queue.h headers since some software
assumes it exists (e.g. the libevent contrib code), but we are not
encouraging their use (NULL should be used instead).

This fixes the following warning (which should arguable be an error since
it results in a function call to an undefined function):

.../contrib/libevent/buffer.c:495:16: warning: implicit declaration of function 'LIST_END' is invalid in C99 [-Wimplicit-function-declaration]
cbent != LIST_END(&buffer->callbacks);
^
.../contrib/libevent/buffer.c:495:13: warning: comparison between pointer and integer ('struct evbuffer_cb_entry *' and 'int') [-Wpointer-integer-compare]
cbent != LIST_END(&buffer->callbacks);
~~~~~ ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Reviewed By: jhb
Differential Revision: https://reviews.freebsd.org/D27151

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sys: clean up empty lines in .c and .h files

Trim trailing white space in comment

Approved by: cognet

Add wakeup_any(), cheaper wakeup_one() for taskqueue(9).

wakeup_one() and underlying sleepq_signal() spend additional time trying
to be fair, waking thread with highest priority, sleeping longest ti

Add wakeup_any(), cheaper wakeup_one() for taskqueue(9).

wakeup_one() and underlying sleepq_signal() spend additional time trying
to be fair, waking thread with highest priority, sleeping longest time.
But in case of taskqueue there are many absolutely identical threads, and
any fairness between them is quite pointless. It makes even worse, since
round-robin wakeups not only make previous CPU affinity in scheduler quite
useless, but also hide from user chance to see CPU bottlenecks, when
sequential workload with one request at a time looks evenly distributed
between multiple threads.

This change adds new SLEEPQ_UNFAIR flag to sleepq_signal(), making it wakeup
thread that went to sleep last, but no longer in context switch (to avoid
immediate spinning on the thread lock). On top of that new wakeup_any()
function is added, equivalent to wakeup_one(), but setting the flag.
On top of that taskqueue(9) is switchied to wakeup_any() to wakeup its
threads.

As result, on 72-core Xeon v4 machine sequential ZFS write to 12 ZVOLs
with 16KB block size spend 34% less time in wakeup_any() and descendants
then it was spending in wakeup_one(), and total write throughput increased
by ~10% with the same as before CPU usage.

Reviewed by: markj, mmacy
MFC after: 2 weeks
Sponsored by: iXsystems, Inc.
Differential Revision: https://reviews.freebsd.org/D20669

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Define QMD_SAVELINK() only for QUEUE_MACRO_DEBUG_TRASH case. Otherwise
with QUEUE_MACRO_DEBUG_TRACE compilation fails due to unused variable.

This commit brings in a new refactored TCP stack called Rack.
Rack includes the following features:
- A different SACK processing scheme (the old sack structures are not used).
- RACK (Recent ackno

This commit brings in a new refactored TCP stack called Rack.
Rack includes the following features:
- A different SACK processing scheme (the old sack structures are not used).
- RACK (Recent acknowledgment) where counting dup-acks is no longer done
instead time is used to knwo when to retransmit. (see the I-D)
- TLP (Tail Loss Probe) where we will probe for tail-losses to attempt
to try not to take a retransmit time-out. (see the I-D)
- Burst mitigation using TCPHTPS
- PRR (partial rate reduction) see the RFC.

Once built into your kernel, you can select this stack by either
socket option with the name of the stack is "rack" or by setting
the global sysctl so the default is rack.

Note that any connection that does not support SACK will be kicked
back to the "default" base FreeBSD stack (currently known as "default").

To build this into your kernel you will need to enable in your
kernel:
makeoptions WITH_EXTRA_TCP_STACKS=1
options TCPHPTS

Sponsored by: Netflix Inc.
Differential Revision: https://reviews.freebsd.org/D15525

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sys: further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 3-Clause license.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for

sys: further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 3-Clause license.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

Special thanks to Wind River for providing access to "The Duke of
Highlander" tool: an older (2014) run over FreeBSD tree was useful as a
starting point.

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Renumber copyright clause 4

Renumber cluase 4 to 3, per what everybody else did when BSD granted
them permission to remove clause 3. My insistance on keeping the same
numbering for legal reasons is

Renumber copyright clause 4

Renumber cluase 4 to 3, per what everybody else did when BSD granted
them permission to remove clause 3. My insistance on keeping the same
numbering for legal reasons is too pedantic, so give up on that point.

Submitted by: Jan Schaumann <jschauma@stevens.edu>
Pull Request: https://github.com/freebsd/freebsd/pull/96

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queue.3: Document existing QMD_* macros

Feedback from: bapt, bdrewery, emaste
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D3983

queue(3): Enhance queue debugging macros

Split the QUEUE_MACRO_DEBUG into QUEUE_MACRO_DEBUG_TRACE and
QUEUE_MACRO_DEBUG_TRASH.

Add the debug macrso QMD_IS_TRASHED() and QMD_SLIST_CHECK_PREVPTR().

queue(3): Enhance queue debugging macros

Split the QUEUE_MACRO_DEBUG into QUEUE_MACRO_DEBUG_TRACE and
QUEUE_MACRO_DEBUG_TRASH.

Add the debug macrso QMD_IS_TRASHED() and QMD_SLIST_CHECK_PREVPTR().

Document these in queue.3.

Reviewed by: emaste
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D3984

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Add two new macros, SLIST_CONCAT and LIST_CONCAT. Note in both the
queue.h header file and in the queue.3 manual page that they are O(n)
so should be used only in low-usage paths with short lists (ot

Add two new macros, SLIST_CONCAT and LIST_CONCAT. Note in both the
queue.h header file and in the queue.3 manual page that they are O(n)
so should be used only in low-usage paths with short lists (otherwise
an STAILQ or TAILQ should be used).

Reviewed by: kib

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Make the system queue header file fully usable within C++ programs by
adding macros to define class lists.

This change is backwards compatible for all use within C and C++
programs. Only C++ program

Make the system queue header file fully usable within C++ programs by
adding macros to define class lists.

This change is backwards compatible for all use within C and C++
programs. Only C++ programs will have added support to use the queue
macros within classes. Previously the queue macros could only be used
within structures.

The queue.3 manual page has been updated to describe the new
functionality and some alphabetic sorting has been done while
at it.

Differential Revision: https://reviews.freebsd.org/D2745
PR: 200827 (exp-run)
MFC after: 2 weeks

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Pass macro arguments properly.

MFC after: 1 week

Fix order of arguments in the TRACEBUF_INITIALIZER macro so that we
can define QUEUE_MACRO_DEBUG to debug list problems.

MFC after: 1 week

Add new FOREACH_FROM variants of the queue(3) FOREACH macros which can
optionally start the traversal from a previously found element by passing the
element in as "var". Passing a NULL "var" retains

Add new FOREACH_FROM variants of the queue(3) FOREACH macros which can
optionally start the traversal from a previously found element by passing the
element in as "var". Passing a NULL "var" retains the same semantics as the
regular FOREACH macros.

Kudos to phk for suggesting the "FROM" suffix instead of my original proposal.

Reviewed by: jhb (previous version), rpaulo
MFC after: 1 week

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Fixes to QUEUE_MACRO_DEBUG support:
- Add const quilifiers to fields that store value of __FILE__.
- Use long type for fields that store value of __LINE__.
- Sort and style(9) debugging fields.
-

Fixes to QUEUE_MACRO_DEBUG support:
- Add const quilifiers to fields that store value of __FILE__.
- Use long type for fields that store value of __LINE__.
- Sort and style(9) debugging fields.
- Add initializer for debugging fields into TAILQ_INITIALIZER macro.

PR: 175759
Submitted by: Andrey Simonenko <simon comsys.ntu-kpi.kiev.ua>
Reviewed by: bde

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Rename __member2struct() to __containerof().

Compared to __member2struct(), this macro has the following advantages:

- It ensures that the type of the pointer is compatible with the member
field

Rename __member2struct() to __containerof().

Compared to __member2struct(), this macro has the following advantages:

- It ensures that the type of the pointer is compatible with the member
field of the structure (or a void pointer).
- It works properly in combination with volatile and const, though
unfortunately it drops these qualifiers from the returned value.

mdf@ proposed to add the container_of() macro, just like Linux has.
Eventually I decided against this, as <sys/param.h> is included all over
the place. It seems container_of() on Linux is specific to the kernel,
not userspace. I'd rather not pollute userspace with this.

I also thought about adding __container_of(), but this would have two
advantages. Xorg seems to already have a __container_of(), which is not
compatible with this version. Also, the underscore in the middle
conflicts with our existing macros (__offsetof, __rangeof, etc).

I'm changing member2struct() to use its old code, as the extra
strictness of this new macro conflicts with existing code (read: cxgb).

MFC after: 1 month

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Correctness: use __member2struct() on the correct fields.

The prev-pointers point to the next-pointers of the previous element --
not the ENTRY structure. The next-pointers are stored in the ENTRY
s

Correctness: use __member2struct() on the correct fields.

The prev-pointers point to the next-pointers of the previous element --
not the ENTRY structure. The next-pointers are stored in the ENTRY
structures first, so the code would already work correctly. Still, it is
more accurate to use the next-fields.

To prevent misuse of __member2struct() in the future, I've got a patch
that requires the pointer to be passed to this macro to be compatible
with the member of the structure. I'll commit this patch after I've
tested it properly.

MFC after: 1 month.

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Implement LIST_PREV().

Regular LISTs have been implemented in such a way that the prev-pointer
does not point to the previous element, but to the next-pointer stored
in the previous element. This is

Implement LIST_PREV().

Regular LISTs have been implemented in such a way that the prev-pointer
does not point to the previous element, but to the next-pointer stored
in the previous element. This is done to simplify LIST_REMOVE(). This
macro can be implemented without knowing the address of the list head.

Unfortunately this makes it harder to implement LIST_PREV(), which is
why this macro was never here. Still, it is possible to implement this
macro. If the prev-pointer points to the list head, we return NULL.
Otherwise we simply subtract the offset of the prev-pointer within the
structure.

It's not as efficient as traversing forward of course, but in practice
it shouldn't be that bad. In almost all use cases, people will want to
compare the value returned by LIST_PREV() against NULL, so an optimizing
compiler will not emit code that does more branching than TAILQs.

While there, make the code a bit more readable by introducing
__member2struct(). This makes STAILQ_LAST() far more readable.

MFC after: 1 month

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