Make swapoff reliable.

The swap_pager_swapoff() function uses trylock for the object lock
before pagein, which means that either i/o to md(4) over swap, or
intensive page faults over swap pager obje

Make swapoff reliable.

The swap_pager_swapoff() function uses trylock for the object lock
before pagein, which means that either i/o to md(4) over swap, or
intensive page faults over swap pager objects might prevent swapoff()
from making any progress. Then the retry < 100 check fails and machine
panics.

If trylock fails, acquire the object lock in the blockable way and
restart the hash bucket walk. Keep retries logic for now.

Reported and tested by: pho
Reviewed by: alc, markj
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Differential revision: https://reviews.freebsd.org/D7688

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Merge ^/head r305029 through r305080.

Restore swap pager readahead after r292373.

The removal of vm_fault_additional_pages() meant that a hard fault on
a swap-backed page would result in only that page being read in. This
change impleme

Restore swap pager readahead after r292373.

The removal of vm_fault_additional_pages() meant that a hard fault on
a swap-backed page would result in only that page being read in. This
change implements readahead and readbehind for the swap pager in
swap_pager_getpages(). swap_pager_haspage() is modified to return the
largest contiguous non-resident range of pages containing the requested
range.

Reviewed by: alc, kib
Tested by: pho
MFC after: 1 month
Differential Revision: https://reviews.freebsd.org/D7677

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Merge ^/head r303250 through r304235.

Explain why swapgeom_close_ev() is delegated.

Sponsored by: The FreeBSD Foundation
MFC after: 1 week

Do not delegate a work to geom event thread which can be done inline.

In particular, swapongeom_ev() needed event thread context when swap
pager configuration was performed under Giant and geom asse

Do not delegate a work to geom event thread which can be done inline.

In particular, swapongeom_ev() needed event thread context when swap
pager configuration was performed under Giant and geom asserted that
Giant is not owned. Now both of the reason went away.

On the other hand, note that swpageom_release() is called from the
bio_done context, and possible close cannot be performed inline.

Also fix some minor issues. The swapgeom() function does not use the
td argument, remove it. Recheck that the vnode passed is still VCHR
and not reclaimed after the lock.

Reviewed by: mav
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks

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Fix style and typo.

Sponsored by: The FreeBSD Foundation
MFC after: 1 week

Fix inconsistent locking of the swap pager named objects list.

Right now, all modifications of the list are locked by sw_alloc_mtx.
But initial lookup of the object by the handle in swap_pager_alloc

Fix inconsistent locking of the swap pager named objects list.

Right now, all modifications of the list are locked by sw_alloc_mtx.
But initial lookup of the object by the handle in swap_pager_alloc()
is not protected by sw_alloc_mtx, which means that
vm_pager_object_lookup() could follow freed pointer.

Create a new named swap object with the OBJT_SWAP type, instead
of OBJT_DEFAULT. With this change, swp_pager_meta_build() never need
to upgrade named OBJT_DEFAULT to OBJT_SWAP (in the other place, we do
not forbid for client code to create named OBJT_DEFAULT objects at
all).

That change allows to remove sw_alloc_mtx and make the list locked by
sw_alloc_sx lock. Update swap_pager_copy() to new locking mode.

Create helper swap_pager_alloc_init() to consolidate named and
anonymous swap objects creation, while a caller ensures that the
neccesary locks are held around the helper.

Reviewed by: alc
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Approved by: re (hrs)

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Explicitely initialize sw_alloc_sx. Currently it is not initialized
but works due to zeroed out bss on startup.

Reviewed by: alc
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Approved by:

Explicitely initialize sw_alloc_sx. Currently it is not initialized
but works due to zeroed out bss on startup.

Reviewed by: alc
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Approved by: re (hrs)

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Remove Giant around allocation of the swap pager with non-NULL handle.
Existing issue of not protecting pager_object_list iteration in
vm_pager_object_lookup() by sw_alloc_mtx is not affected by Gian

Remove Giant around allocation of the swap pager with non-NULL handle.
Existing issue of not protecting pager_object_list iteration in
vm_pager_object_lookup() by sw_alloc_mtx is not affected by Giant
removal.

Reviewed by: alc
Sponsored by: The FreeBSD Foundation

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Mark swap-related proc sysctls as not requiring Giant.

Reviewed by: alc (as part of larger patch)
Sponsored by: The FreeBSD Foundation

Replace hand-made exclusive lock, protecting against parallel
swapon/swapoff invocations, with sx.

Reviewed by: alc (as part of larger patch)
Sponsored by: The FreeBSD Foundation

sys/vm: minor spelling fixes in comments.

No functional change.

MFH r289384-r293170

Sponsored by: The FreeBSD Foundation

MFH @r292599

This includes the pluggable TCP framework and other chnages to the
netstack to track for VNET stability.

Security: The FreeBSD Foundation

A change to KPI of vm_pager_get_pages() and underlying VOP_GETPAGES().

o With new KPI consumers can request contiguous ranges of pages, and
unlike before, all pages will be kept busied on return,

A change to KPI of vm_pager_get_pages() and underlying VOP_GETPAGES().

o With new KPI consumers can request contiguous ranges of pages, and
unlike before, all pages will be kept busied on return, like it was
done before with the 'reqpage' only. Now the reqpage goes away. With
new interface it is easier to implement code protected from race
conditions.

Such arrayed requests for now should be preceeded by a call to
vm_pager_haspage() to make sure that request is possible. This
could be improved later, making vm_pager_haspage() obsolete.

Strenghtening the promises on the business of the array of pages
allows us to remove such hacks as swp_pager_free_nrpage() and
vm_pager_free_nonreq().

o New KPI accepts two integer pointers that may optionally point at
values for read ahead and read behind, that a pager may do, if it
can. These pages are completely owned by pager, and not controlled
by the caller.

This shifts the UFS-specific readahead logic from vm_fault.c, which
should be file system agnostic, into vnode_pager.c. It also removes
one VOP_BMAP() request per hard fault.

Discussed with: kib, alc, jeff, scottl
Sponsored by: Nginx, Inc.
Sponsored by: Netflix

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Merge from head

Sponsored by: Gandi.net

Merge from head

Sync up with head up to r289211.

Merge from head

Merge ^/head r288836 through r288925.

Mark swap_pager_putpages static at its definition. It was already
static at its declaration. Remove needless swapdev_strategy forward
declaration.

MFC After: 3 days

Finish merging from head, messed up in previous attempt

Merge from head

Merge ^/head r287527 through r287679.