vmspace: Convert to refcount(9)

This is mostly mechanical except for vmspace_exit(). There, use the new
refcount_release_if_last() to avoid switching to vmspace0 unless other
processes are sharing

vmspace: Convert to refcount(9)

This is mostly mechanical except for vmspace_exit(). There, use the new
refcount_release_if_last() to avoid switching to vmspace0 unless other
processes are sharing the vmspace. In that case, upon switching to
vmspace0 we can unconditionally release the reference.

Remove the volatile qualifier from vm_refcnt now that accesses are
protected using refcount(9) KPIs.

Reviewed by: alc, kib, mmel
MFC after: 1 month
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D27057

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Merge ^/head r352105 through r352307.

Change synchonization rules for vm_page reference counting.

There are several mechanisms by which a vm_page reference is held,
preventing the page from being freed back to the page allocator. In
pa

Change synchonization rules for vm_page reference counting.

There are several mechanisms by which a vm_page reference is held,
preventing the page from being freed back to the page allocator. In
particular, holding the page's object lock is sufficient to prevent the
page from being freed; holding the busy lock or a wiring is sufficent as
well. These references are protected by the page lock, which must
therefore be acquired for many per-page operations. This results in
false sharing since the page locks are external to the vm_page
structures themselves and each lock protects multiple structures.

Transition to using an atomically updated per-page reference counter.
The object's reference is counted using a flag bit in the counter. A
second flag bit is used to atomically block new references via
pmap_extract_and_hold() while removing managed mappings of a page.
Thus, the reference count of a page is guaranteed not to increase if the
page is unbusied, unmapped, and the object's write lock is held. As
a consequence of this, the page lock no longer protects a page's
identity; operations which move pages between objects are now
synchronized solely by the objects' locks.

The vm_page_wire() and vm_page_unwire() KPIs are changed. The former
requires that either the object lock or the busy lock is held. The
latter no longer has a return value and may free the page if it releases
the last reference to that page. vm_page_unwire_noq() behaves the same
as before; the caller is responsible for checking its return value and
freeing or enqueuing the page as appropriate. vm_page_wire_mapped() is
introduced for use in pmap_extract_and_hold(). It fails if the page is
concurrently being unmapped, typically triggering a fallback to the
fault handler. vm_page_wire() no longer requires the page lock and
vm_page_unwire() now internally acquires the page lock when releasing
the last wiring of a page (since the page lock still protects a page's
queue state). In particular, synchronization details are no longer
leaked into the caller.

The change excises the page lock from several frequently executed code
paths. In particular, vm_object_terminate() no longer bounces between
page locks as it releases an object's pages, and direct I/O and
sendfile(SF_NOCACHE) completions no longer require the page lock. In
these latter cases we now get linear scalability in the common scenario
where different threads are operating on different files.

__FreeBSD_version is bumped. The DRM ports have been updated to
accomodate the KPI changes.

Reviewed by: jeff (earlier version)
Tested by: gallatin (earlier version), pho
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D20486

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Merge ^/head r351317 through r351731.

cxgbe/t4_tom: Initialize all TOE connection parameters in one place.
Remove now-redundant items from toepcb and synq_entry and the code to
support them.

Let the driver calculate tx_align, rx_coalesc

cxgbe/t4_tom: Initialize all TOE connection parameters in one place.
Remove now-redundant items from toepcb and synq_entry and the code to
support them.

Let the driver calculate tx_align, rx_coalesce, and sndbuf by default.

Reviewed by: jhb@
MFC after: 1 week
Sponsored by: Chelsio Communications
Differential Revision: https://reviews.freebsd.org/D21387

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MFHead @r350386

Sponsored by: The FreeBSD Foundation

Merge the vm_page hold and wire mechanisms.

The hold_count and wire_count fields of struct vm_page are separate
reference counters with similar semantics. The remaining essential
differences are th

Merge the vm_page hold and wire mechanisms.

The hold_count and wire_count fields of struct vm_page are separate
reference counters with similar semantics. The remaining essential
differences are that holds are not counted as a reference with respect
to LRU, and holds have an implicit free-on-last unhold semantic whereas
vm_page_unwire() callers must explicitly determine whether to free the
page once the last reference to the page is released.

This change removes the KPIs which directly manipulate hold_count.
Functions such as vm_fault_quick_hold_pages() now return wired pages
instead. Since r328977 the overhead of maintaining LRU for wired pages
is lower, and in many cases vm_fault_quick_hold_pages() callers would
swap holds for wirings on the returned pages anyway, so with this change
we remove a number of page lock acquisitions.

No functional change is intended. __FreeBSD_version is bumped.

Reviewed by: alc, kib
Discussed with: jeff
Discussed with: jhb, np (cxgbe)
Tested by: pho (previous version)
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D19247

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cxgbe/t4_tom: Tweaks to some of the AIO related CTRs.

Reviewed by: jhb@
MFC after: 1 week
Sponsored by: Chelsio Communications

MFHead @349476

Sponsored by: The FreeBSD Foundation

cxgbe/t4_tom: DDP_DEAD is a ddp flag and not a toepcb flag.

The driver was in effect setting TPF_ABORT_SHUTDOWN on the toepcb
instead of what was intended.

MFC after: 1 week
Sponsored by: Chelsio C

cxgbe/t4_tom: DDP_DEAD is a ddp flag and not a toepcb flag.

The driver was in effect setting TPF_ABORT_SHUTDOWN on the toepcb
instead of what was intended.

MFC after: 1 week
Sponsored by: Chelsio Communications

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MFHead @348740

Sponsored by: The FreeBSD Foundation

cxgbe/t4_tom: adjust the hardware receive window to match changes to the
receive sockbuf's high water mark.

Calculate rx credits on the spot instead of tracking sbused/sb_cc and
rx_credits in the to

cxgbe/t4_tom: adjust the hardware receive window to match changes to the
receive sockbuf's high water mark.

Calculate rx credits on the spot instead of tracking sbused/sb_cc and
rx_credits in the toepcb. The previous method worked when the high
water mark changed due to SB_AUTOSIZE but not when it was adjusted
directly (for example, by the soreserve in nfsrvd_addsock).

This fixes a connection hang while running iozone over an NFS mounted
share where nfsd's TCP sockets are being handled by t4_tom.

MFC after: 3 days
Sponsored by: Chelsio Communications

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MFHead@r345880

cxgbe/t4_tom: Catch up with r344433, which removed tcb_autorcvbuf_inc.

The declaration in tcp_var.h is still around so t4_tom continued to
compile but wouldn't load. A separate commit will fix tcp_

cxgbe/t4_tom: Catch up with r344433, which removed tcb_autorcvbuf_inc.

The declaration in tcp_var.h is still around so t4_tom continued to
compile but wouldn't load. A separate commit will fix tcp_var.h

Reported By: Dustin Marquess (dmarquess at gmail)

Sponsored by: Chelsio Communications

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Merge ^/head r338298 through r338391.

cxgbe/tom: Unregister shared CPL handlers on module unload. This fixes
a panic with INVARIANTS that occurs when t4_tom is unloaded and reloaded.

Approved by: re@ (kib@)

cxgbe(4): Use opaque cookies or tid range-checks to determine the
intended recipient of a CPL when it can't be determined solely from the
opcode. Retire the per-queue handlers for such CPLs in favor

cxgbe(4): Use opaque cookies or tid range-checks to determine the
intended recipient of a CPL when it can't be determined solely from the
opcode. Retire the per-queue handlers for such CPLs in favor of the new
scheme.

Sponsored by: Chelsio Communications

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Use the offload transmit queue to set flags on TLS connections.

Requests to modify the state of TLS connections need to be sent on the
same queue as TLS record transmit requests to ensure ordering.

Use the offload transmit queue to set flags on TLS connections.

Requests to modify the state of TLS connections need to be sent on the
same queue as TLS record transmit requests to ensure ordering.

However, in order to use the offload transmit queue in t4_set_tcb_field(),
the function needs to be updated to do proper flow control / credit
management when queueing a request to an offload queue. This required
passing a pointer to the toepcb itself to this function, so while here
remove the 'tid' and 'iqid' parameters and obtain those values from the
toepcb in t4_set_tcb_field() itself.

Submitted by: Harsh Jain @ Chelsio (original version)
Reviewed by: np
Sponsored by: Chelsio Communications
Differential Revision: https://reviews.freebsd.org/D14871

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Simplify error handling in t4_tom.ko module loading.

- Change t4_ddp_mod_load() to return void instead of always returning
success. This avoids having to pretend to have proper support for
unlo

Simplify error handling in t4_tom.ko module loading.

- Change t4_ddp_mod_load() to return void instead of always returning
success. This avoids having to pretend to have proper support for
unloading when only part of t4_tom_mod_load() has run.
- If t4_register_uld() fails, don't invoke t4_tom_mod_unload() directly.
The module handling code in the kernel invokes MOD_UNLOAD on a module
whose MOD_LOAD fails with an error already.

Reviewed by: np (part of a larger patch)
MFC after: 1 month
Sponsored by: Chelsio Communications

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Move DDP PCB state into a helper structure.

This consolidates all of the DDP state in one place. Also, the code has
now been fixed to ensure that DDP state is only accessed for DDP
connections. Th

Move DDP PCB state into a helper structure.

This consolidates all of the DDP state in one place. Also, the code has
now been fixed to ensure that DDP state is only accessed for DDP
connections. This should not be a functional change but makes it cleaner
and easier to add state for other TOE socket modes in the future.

MFC after: 1 month
Sponsored by: Chelsio Communications

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sys/dev: further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error

sys/dev: further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

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.

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Merge ^/head r323559 through r325504.

MFhead@r324837

While here, diff reduce some of the changes in sys/boot by moving
MK_COVERAGE=no to sys/boot/Makefile.inc .

cxgbe: delete now-redundant vnet decls

r324539 gathered some vnet decls into netinet/tcp_var.h, so that they
are now redundant in dev/cxgbe/tom/{t4_cpl_io.c,t4_ddp.c}. This triggers
gcc -Wredundant-

cxgbe: delete now-redundant vnet decls

r324539 gathered some vnet decls into netinet/tcp_var.h, so that they
are now redundant in dev/cxgbe/tom/{t4_cpl_io.c,t4_ddp.c}. This triggers
gcc -Wredundant-decls.

Reviewed by: np
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D12674

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MFhead@r323635