Perform a single batched update to the object's paging-in-progress count
rather than updating it for each page.

Merge ^/head r288197 through r288456.

Merge from head

As a step towards the elimination of PG_CACHED pages, rework the handling
of POSIX_FADV_DONTNEED so that it causes the backing pages to be moved to
the head of the inactive queue instead of being cac

As a step towards the elimination of PG_CACHED pages, rework the handling
of POSIX_FADV_DONTNEED so that it causes the backing pages to be moved to
the head of the inactive queue instead of being cached.

This affects the implementation of POSIX_FADV_NOREUSE as well, since it
works by applying POSIX_FADV_DONTNEED to file ranges after they have been
read or written. At that point the corresponding buffers may still be
dirty, so the previous implementation would coalesce successive ranges and
apply POSIX_FADV_DONTNEED to the result, ensuring that pages backing the
dirty buffers would eventually be cached. To preserve this behaviour in an
efficient manner, this change adds a new buf flag, B_NOREUSE, which causes
the pages backing a VMIO buf to be placed at the head of the inactive queue
when the buf is released. POSIX_FADV_NOREUSE then works by setting this
flag in bufs that underlie the specified range.

Reviewed by: alc, kib
Sponsored by: EMC / Isilon Storage Division
Differential Revision: https://reviews.freebsd.org/D3726

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Sync up with head (up to r288341).

- Collapse vfs_vmio_truncate & vfs_vmio_release into a single function.
- Allow vfs_vmio_invalidate() to free the pages, leaving us with a
single loop and bufobj lock when B_NOCACHE/B_INVAL is us

- Collapse vfs_vmio_truncate & vfs_vmio_release into a single function.
- Allow vfs_vmio_invalidate() to free the pages, leaving us with a
single loop and bufobj lock when B_NOCACHE/B_INVAL is used.
- Eliminate the special B_ASYNC handling on free that has not been
relevant for some time.
- Remove the extraneous page busy from vfs_vmio_truncate().

Reviewed by: kib
Tested by: pho
Sponsored by: EMC / Isilon storage division

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Merge ^/head r288126 through r288196.

- Fix a nonsense reordering that somehow slipped into my last diff.

Reported by: pho

Some refactoring of the buf/vm interface.
- Eliminate bogus page replacement that is inconsistently applied in the
invalidation loop in brelse. This has been a no-op in modern times as
biodon

Some refactoring of the buf/vm interface.
- Eliminate bogus page replacement that is inconsistently applied in the
invalidation loop in brelse. This has been a no-op in modern times as
biodone() is responsible for cleaning up after bogus pages. This
would've spammed the console with printfs at a minimum.
- Allow the compiler and human readers alike to reason about allocbuf()
by splitting it into constituent parts.
- Separate the VM manipulating and buf manipulating code in brelse() and
bufdone() so that the intentions are clear. This makes it evident that
there are several duplicated buf pages loops that will be consolidated
at a later time.

Reviewed by: kib
Tested by: pho
Sponsored by: EMC / Isilon Storage Division

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Merge ^/head r288100 through r288125.

Change vm_page_unwire() such that it (1) accepts PQ_NONE as the specified
queue and (2) returns a Boolean indicating whether the page's wire count
transitioned to zero.

Exploit this change in vfs_vm

Change vm_page_unwire() such that it (1) accepts PQ_NONE as the specified
queue and (2) returns a Boolean indicating whether the page's wire count
transitioned to zero.

Exploit this change in vfs_vmio_release() to avoid pointlessly enqueueing
a page that is about to be freed.

(An earlier version of this change was developed by attilio@ and kmacy@.
Any errors in this version are my own.)

Reviewed by: kib
Sponsored by: EMC / Isilon Storage Division

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Finish merging from head, messed up in previous attempt

Merge from head

Merge ^/head r287527 through r287679.

bufdonebio is now unused. Retire it too.

dev_strategy and dev_strategy_csw are unused since r281825. Remove
them.

Differential Revision: https://reviews.freebsd.org/D3620

Catch up with head, primarily for the 1.14.4.0 firmware.

Merge ^/head r285924 through r286421.

vfs: fill fallout from r286076

This right operator is >= not =>.

Reported by: cem

vfs: fix off-by-one error in vfs_buf_check_mapped

The check added in r285872 can trigger for valid buffers if the buffer space
used happens to be just after unmapped_buf in KVA space.

Discussed wit

vfs: fix off-by-one error in vfs_buf_check_mapped

The check added in r285872 can trigger for valid buffers if the buffer space
used happens to be just after unmapped_buf in KVA space.

Discussed with: kib
Sponsored by: Citrix Systems R&D

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Move bufshutdown() out of the #ifdef INVARIANTS block.

- Make 'struct buf *buf' private to vfs_bio.c. Having a global variable
'buf' is inconvenient and has lead me to some irritating to discover
bugs over the years. It also makes it more challen

- Make 'struct buf *buf' private to vfs_bio.c. Having a global variable
'buf' is inconvenient and has lead me to some irritating to discover
bugs over the years. It also makes it more challenging to refactor
the buf allocation system.
- Move swbuf and declare it as an extern in vfs_bio.c. This is still
not perfect but better than it was before.
- Eliminate the unused ffs function that relied on knowledge of the buf
array.
- Move the shutdown code that iterates over the buf array into vfs_bio.c.

Reviewed by: kib
Sponsored by: EMC / Isilon Storage Division

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- Eliminate the EMPTYKVA queue. It served as a cache of KVA allocations
attached to bufs to avoid the overhead of the vm. This purposes is now
better served by vmem. Freeing the kva immediat

- Eliminate the EMPTYKVA queue. It served as a cache of KVA allocations
attached to bufs to avoid the overhead of the vm. This purposes is now
better served by vmem. Freeing the kva immediately when a buf is
destroyed leads to lower fragmentation and a much simpler scan algorithm.

Reviewed by: kib
Sponsored by: EMC / Isilon Storage Division

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Merge ^/head r285793 through r285923.

With the removal of b_saveaddr in the r285819, b_data must be reset to
b_kvabase when the buffer is reclaimed. Otherwise, if b_data for the
mapped buffer was adjusted with the page-offset portion of

With the removal of b_saveaddr in the r285819, b_data must be reset to
b_kvabase when the buffer is reclaimed. Otherwise, if b_data for the
mapped buffer was adjusted with the page-offset portion of b_offset,
nothing would re-adjust the b_data, which breaks buffer management
code which expects page-aligned b_data (see e.g. bpman_qenter(), which
skips partial pages).

Fix a minor issue with the GB_KVAALLOC requests, which could result in
returning the mapped buffer if the reused buffer is mapped and have
the right amount of KVA reserved.

Improve assertion in the vfs_buf_check_mapped() to catch unmapped
buffers which have their b_data incorrectly adjusted with offset.

Reported and tested by: pho (previous version)
Reviewed by: jeff (previous version)
Sponsored by: The FreeBSD Foundation

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