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

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

Enable bioq 'car limit' added at r335066 at 128 bios.

Without the 'car limit' enabled (before this), running sequential ZFS scrub
on HDD without command queuing support, I've measured latency on con

Enable bioq 'car limit' added at r335066 at 128 bios.

Without the 'car limit' enabled (before this), running sequential ZFS scrub
on HDD without command queuing support, I've measured latency on concurrent
random reads reaching 4 seconds (surprised that not more). Enabling this
reduced the latency to 65 milliseconds, while scrub still doing ~180MB/s.

For disks with command queuing this does not make much difference (if any),
since most time all the requests are queued down to the disk or HBA, leaving
nothing in the queue to sort. And even if something does not fit, staying on
the queue, it is likely not for long. To not limit sorting in such bursty
scenarios I've added batched counter zeroing when the queue is getting empty.

The internal scheduler of the SAS HDD I was testing seems to be even more
loyal to random I/O, reducing the scrub speed to ~120MB/s. So in case
somebody worried this is limit is too strict -- it actually looks relaxed.

MFC after: 2 weeks
Sponsored by: iXsystems, Inc.

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MFHead@r345275

Fix botched merge with 355066

When merging from Netflix's tree, resetting the carsize was dropped
accidentally. This fix fixes that revision by properly resetting how
many are in the car.

Noticed b

Fix botched merge with 355066

When merging from Netflix's tree, resetting the carsize was dropped
accidentally. This fix fixes that revision by properly resetting how
many are in the car.

Noticed by: mav@

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Merge ^/head r343571 through r343711.

Only sort requests of types that have concept of offset.

Other types, such as BIO_FLUSH or BIO_ZONE, or especially new/unknown ones,
may imply some degree of ordering even if strict ordering is not

Only sort requests of types that have concept of offset.

Other types, such as BIO_FLUSH or BIO_ZONE, or especially new/unknown ones,
may imply some degree of ordering even if strict ordering is not requested
explicitly.

MFC after: 2 weeks
Sponsored by: iXsystems, Inc.

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Implement a 'car limit' for bioq.

Allow one to implement a 'car limit' for
bioq_disksort. debug.bioq_batchsize sets the size of car limit. Every
time we queue that many requests, we start over so th

Implement a 'car limit' for bioq.

Allow one to implement a 'car limit' for
bioq_disksort. debug.bioq_batchsize sets the size of car limit. Every
time we queue that many requests, we start over so that we limit the
latency for requests when the software queue depths are large. A value
of '0', the default, means to revert to the old behavior.

Sponsored by: Netflix

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SPDX: use the Beerware identifier.

Merge svn+ssh://svn.freebsd.org/base/head@214309

Correct bioq_disksort so that bioq_insert_tail() offers barrier semantic.
Add the BIO_ORDERED flag for struct bio and update bio clients to use it.

The barrier semantics of bioq_insert_tail() were b

Correct bioq_disksort so that bioq_insert_tail() offers barrier semantic.
Add the BIO_ORDERED flag for struct bio and update bio clients to use it.

The barrier semantics of bioq_insert_tail() were broken in two ways:

o In bioq_disksort(), an added bio could be inserted at the head of
the queue, even when a barrier was present, if the sort key for
the new entry was less than that of the last queued barrier bio.

o The last_offset used to generate the sort key for newly queued bios
did not stay at the position of the barrier until either the
barrier was de-queued, or a new barrier (which updates last_offset)
was queued. When a barrier is in effect, we know that the disk
will pass through the barrier position just before the
"blocked bios" are released, so using the barrier's offset for
last_offset is the optimal choice.

sys/geom/sched/subr_disk.c:
sys/kern/subr_disk.c:
o Update last_offset in bioq_insert_tail().

o Only update last_offset in bioq_remove() if the removed bio is
at the head of the queue (typically due to a call via
bioq_takefirst()) and no barrier is active.

o In bioq_disksort(), if we have a barrier (insert_point is non-NULL),
set prev to the barrier and cur to it's next element. Now that
last_offset is kept at the barrier position, this change isn't
strictly necessary, but since we have to take a decision branch
anyway, it does avoid one, no-op, loop iteration in the while
loop that immediately follows.

o In bioq_disksort(), bypass the normal sort for bios with the
BIO_ORDERED attribute and instead insert them into the queue
with bioq_insert_tail(). bioq_insert_tail() not only gives
the desired command order during insertion, but also provides
barrier semantics so that commands disksorted in the future
cannot pass the just enqueued transaction.

sys/sys/bio.h:
Add BIO_ORDERED as bit 4 of the bio_flags field in struct bio.

sys/cam/ata/ata_da.c:
sys/cam/scsi/scsi_da.c
Use an ordered command for SCSI/ATA-NCQ commands issued in
response to bios with the BIO_ORDERED flag set.

sys/cam/scsi/scsi_da.c
Use an ordered tag when issuing a synchronize cache command.

Wrap some lines to 80 columns.

sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev_geom.c
sys/geom/geom_io.c
Mark bios with the BIO_FLUSH command as BIO_ORDERED.

Sponsored by: Spectra Logic Corporation
MFC after: 1 month

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Revert r210225 - turns out I was wrong; the "/*-" is not license-only
thing; it's also used to indicate that the comment should not be automatically
rewrapped.

Explained by: cperciva@

The "/*-" comment marker is supposed to denote copyrights. Remove non-copyright
occurences from sys/sys/ and sys/kern/.

Merge from head up to r188941 (last revision before the USB stack switch)

Update the projects tree to a newer FreeBSD current.

Clarify and reimplement the bioq API so that bioq_disksort() has
the correct behaviour (sorting by distance from the current head position
in the scan direction) and bioq_insert_head() and bioq_inser

Clarify and reimplement the bioq API so that bioq_disksort() has
the correct behaviour (sorting by distance from the current head position
in the scan direction) and bioq_insert_head() and bioq_insert_tail()
have a well defined (and useful) behaviour, especially when intermixed
with calls to bioq_disksort().

In particular:
- fix a bug in the existing bioq_disksort() that did not use the
current head position correctly;
- redefine semantics of bioq_insert_head() and bioq_insert_tail().
bioq_insert_tail() can now be used as a barrier
between previous and subsequent calls to bioq_disksort().

The code is heavily documented in the source code so please refer
to that for the details.

Much of this code comes from Fabio Checconi. Also thanks to Kirk
for feedback on the (re)definition of bioq_insert_tail().

NOTE: in the current tree there is only a handful of files which
intermix calls to bioq_disksort() with bioq_insert_head() and
bioq_insert_tail(). The ordering of the queue in these situation
was not specified (nor easy to figure out) before, so I doubt any
of that code could be affected by the specification of the API.

Also note that the current implementation is significantly simpler
than the previous one (also used in ata_sort_queue()).
It would be useful to reimplement ata_sort_queue() using
the same code used in bioq_disksort().

MFC after: 1 week

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Make bioq_disksort have a ANSI-C definition rather than a K&R definition.

Add a new I/O request - BIO_FLUSH, which basically tells providers below to
flush their caches. For now will mostly be used by disks to flush their
write cache.

Sponsored by: home.pl

Unexpand TAILQ_FIRST(foo) == NULL to TAILQ_EMPTY(foo).

When calling bioq_first() to see if a queue is empty in bioq_disksort(),
don't save the return value as we won't use it.

Noticed by: Coverity Prevent analysis tool
MFC after: 3 days

- Fix insertions of bios which represent data earlier than anything else
in the queue. The insertion sort assumed this had already been taken
care of.

Spotted by: Antoine Brodin
Approved by:

- Fix insertions of bios which represent data earlier than anything else
in the queue. The insertion sort assumed this had already been taken
care of.

Spotted by: Antoine Brodin
Approved by: re (scottl)

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- Dramatically simplify bioqdisksort(). We no longer do ordered bios so
most of the code to deal with them has been dead for sometime. Simplify
the code by doing an insert sort hinted by the

- Dramatically simplify bioqdisksort(). We no longer do ordered bios so
most of the code to deal with them has been dead for sometime. Simplify
the code by doing an insert sort hinted by the current head position.

Met with apathy by: arch@

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/* -> /*- for copyright notices, minor format tweaks as necessary

Add bioq_insert_head() function.

OK'd by: phk

Add bioq_takefirst().

If the bioq is empty, NULL is returned. Otherwise the front element
is removed and returned.

This can simplify locking in many drivers from:

lock()
bp = bioq_first(bq);
i

Add bioq_takefirst().

If the bioq is empty, NULL is returned. Otherwise the front element
is removed and returned.

This can simplify locking in many drivers from:

lock()
bp = bioq_first(bq);
if (bp == NULL) {
unlock()
return
}
bioq_remove(bp, bq)
unlock
to:
lock()
bp = bioq_takefirst(bq);
unlock()
if (bp == NULL)
return;

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Report bio_pblkbo instead of bio_blkno.