Put back in the simplification of the aiodone daemon.

Previous "breakage" of the swap on arm64 has been found to be an issue
on one machine the rockpro/arm64 related to a deadlock built into the
sdmmc(4) stack interacting with swapping code both running under
KERNEL_LOCK().

This issue is easily reproducible on -current and entering swap when
building LLVM on a rockpro crashes the machine by memory corruption.

Tested by mlarkin@ on octeon & i386, by myself on amd64 & arm64 and by
sthen@ on i386 port bulk.

ok beck@ some time ago.

Previous commit message:

Simplify the aiodone daemon which is only used for async writes.

- Remove unused support for asynchronous read, including error conditions

- Grab the proper lock for each page that has been written to swap. This
allows to enable an assertion in uvm_page_unbusy().

- Move the uvm_anon_release() call outside of uvm_page_unbusy() and
assert for the different anon cases.

ok beck@, kettenis@

Revert simplification of the aiodone daemon it breaks swap on arm64.

Found the hard way by mlarkin@ and deraadt@.

Simplify the aiodone daemon which is only used for async writes.

- Remove unused support for asynchronous read, including error conditions

- Grab the proper lock for each page that has been written to swap. This
allows to enable an assertion in uvm_page_unbusy().

- Move the uvm_anon_release() call outside of uvm_page_unbusy() and
assert for the different anon cases.

ok beck@, kettenis@

Constify and use C99 initializer for "struct uvm_pagerops".

While here put some KERNEL_ASSERT_LOCKED() in the functions called from
the page fault handler. The removal of locking of `uobj' will need to be
revisited and these are good indicator that something is missing and that
many comments are lying.

ok kettenis

Chuck Cranor rescinded clauses in his license
on the 2nd of February 2011 in NetBSD.

http://marc.info/?l=netbsd-source-changes&m=129658899212732&w=2
http://marc.info/?l=netbsd-source-changes&m=129659095515558&w=2
http://marc.info/?l=netbsd-source-changes&m=129659157916514&w=2
http://marc.info/?l=netbsd-source-changes&m=129665962324372&w=2
http://marc.info/?l=netbsd-source-changes&m=129666033625342&w=2
http://marc.info/?l=netbsd-source-changes&m=129666052825545&w=2
http://marc.info/?l=netbsd-source-changes&m=129666922906480&w=2
http://marc.info/?l=netbsd-source-changes&m=129667725518082&w=2

forgot to say: aobj grow/shrink tweaks are mostly from Pedro Martelletto,
like the rest of tmpfs

allow aobj to shrink grow, for tmpfs support
A few tweaks asked by kettenis@
(code doesn't affect systems without mounted tmpfs at all)

okay beck@

Don't leak swapslots when doing a uvm_km_pgremove and a page is in swap only.

Before we were only calling uao_dropswap() if there was a page, maning
that if the buffer was swapped out then we would leak the slot.

Quite rare because only pipebuffers should swap from the kernel object,
but i've seen panics that implied this had happened (alpha.p for example).

ok thib@ after a lot of discussion and checking the semantics.

Put the PG_RELEASED changes diff back in.

This has has been tested very very thoroughly on all archs we have
excepting 88k and 68k. Please see cvs log for the individual commit
messages.

ok beck@, thib@

date based reversion of uvm to the 4th May.

We still have no idea why this stops the crashes. but it does.

a machine forced to 64mb of ram cycled 10GB through swap with this diff
and is still running as I type this. Other tests by ariane@ and thib@
also seem to show that it's alright.

ok deraadt@, thib@, ariane@

Backout all the PG_RELEASED changes.

This is for the same reason as the earlier backouts, to avoid the bug
either added or exposed sometime around c2k9. This *should* be the last
one.

prompted by deraadt@

ok ariane@

The first step in cleaning up the use of PG_RELEASED for uvm objects.

Now, the PG_ RELEASED flag currently has two (maybe three) uses. The
valid one is for use with async io where we want to free the page after
we've paged it out. The other ones are "oh i'd like to free this, but
someone else is playing with it". It's simpler to just sleep on the
damned page instead and stop the fiddling.

First step does uao's: in uao_detach, sleep on the object and free it
when we're clean, instead of setting a flag so it's freed after. In
uao_flush, do the same. Change the interation over the object in flush
so that we don't have to add marker pages or other such voodoo to the
list when we sleep (netbsd did that when they had a similar diff), just
use the hash always. We can now change uao_releasepg() to just free the
page, and not bother with the KILLME stuff. When the other objects are
fixed this hook will vanish.

Much discussion with art@ over the idea, and ariane@ over this specific
diff. As mentioned, this one is based loosely on a similar idea in
netbsd.

Been in my tree for a while, survived many make builds, etc, and forcing
paging using ariane's evil program.

ok ariane@, beck@.

First round of __P removal in sys

branches: 1.7.4;
Add support for disabling swap devices (swapctl -d).
Improve error handling on I/O errors to swap.
From NetBSD

Protect protypes, certain macros, and inlines from userland. Checked userland
with a 'make build'. From NetBSD. art@ ok

$OpenBSD$

Fix the NetBSD id strings.

branches: 1.3.4;
sync with NetBSD from 1999.05.24 (there is a reason for this date)
Mostly cleanups, but also a few improvements to pagedaemon for better
handling of low memory and/or low swap conditions.

add OpenBSD tags

Import of uvm from NetBSD. Some local changes, some code disabled

Revert simplification of the aiodone daemon it breaks swap on arm64.

Found the hard way by mlarkin@ and deraadt@.

Simplify the aiodone daemon which is only used for async writes.

- Remove unused support for asynchronous read, including error conditions

- Grab the proper lock for each page that has been written to swap. This
allows to enable an assertion in uvm_page_unbusy().

- Move the uvm_anon_release() call outside of uvm_page_unbusy() and
assert for the different anon cases.

ok beck@, kettenis@

Constify and use C99 initializer for "struct uvm_pagerops".

While here put some KERNEL_ASSERT_LOCKED() in the functions called from
the page fault handler. The removal of locking of `uobj' will need to be
revisited and these are good indicator that something is missing and that
many comments are lying.

ok kettenis

Chuck Cranor rescinded clauses in his license
on the 2nd of February 2011 in NetBSD.

http://marc.info/?l=netbsd-source-changes&m=129658899212732&w=2
http://marc.info/?l=netbsd-source-changes&m=129659095515558&w=2
http://marc.info/?l=netbsd-source-changes&m=129659157916514&w=2
http://marc.info/?l=netbsd-source-changes&m=129665962324372&w=2
http://marc.info/?l=netbsd-source-changes&m=129666033625342&w=2
http://marc.info/?l=netbsd-source-changes&m=129666052825545&w=2
http://marc.info/?l=netbsd-source-changes&m=129666922906480&w=2
http://marc.info/?l=netbsd-source-changes&m=129667725518082&w=2

forgot to say: aobj grow/shrink tweaks are mostly from Pedro Martelletto,
like the rest of tmpfs

allow aobj to shrink grow, for tmpfs support
A few tweaks asked by kettenis@
(code doesn't affect systems without mounted tmpfs at all)

okay beck@

Don't leak swapslots when doing a uvm_km_pgremove and a page is in swap only.

Before we were only calling uao_dropswap() if there was a page, maning
that if the buffer was swapped out then we would leak the slot.

Quite rare because only pipebuffers should swap from the kernel object,
but i've seen panics that implied this had happened (alpha.p for example).

ok thib@ after a lot of discussion and checking the semantics.

Put the PG_RELEASED changes diff back in.

This has has been tested very very thoroughly on all archs we have
excepting 88k and 68k. Please see cvs log for the individual commit
messages.

ok beck@, thib@

date based reversion of uvm to the 4th May.

We still have no idea why this stops the crashes. but it does.

a machine forced to 64mb of ram cycled 10GB through swap with this diff
and is still running as I type this. Other tests by ariane@ and thib@
also seem to show that it's alright.

ok deraadt@, thib@, ariane@

Backout all the PG_RELEASED changes.

This is for the same reason as the earlier backouts, to avoid the bug
either added or exposed sometime around c2k9. This *should* be the last
one.

prompted by deraadt@

ok ariane@

The first step in cleaning up the use of PG_RELEASED for uvm objects.

Now, the PG_ RELEASED flag currently has two (maybe three) uses. The
valid one is for use with async io where we want to free the page after
we've paged it out. The other ones are "oh i'd like to free this, but
someone else is playing with it". It's simpler to just sleep on the
damned page instead and stop the fiddling.

First step does uao's: in uao_detach, sleep on the object and free it
when we're clean, instead of setting a flag so it's freed after. In
uao_flush, do the same. Change the interation over the object in flush
so that we don't have to add marker pages or other such voodoo to the
list when we sleep (netbsd did that when they had a similar diff), just
use the hash always. We can now change uao_releasepg() to just free the
page, and not bother with the KILLME stuff. When the other objects are
fixed this hook will vanish.

Much discussion with art@ over the idea, and ariane@ over this specific
diff. As mentioned, this one is based loosely on a similar idea in
netbsd.

Been in my tree for a while, survived many make builds, etc, and forcing
paging using ariane's evil program.

ok ariane@, beck@.

First round of __P removal in sys

branches: 1.7.4;
Add support for disabling swap devices (swapctl -d).
Improve error handling on I/O errors to swap.
From NetBSD

Protect protypes, certain macros, and inlines from userland. Checked userland
with a 'make build'. From NetBSD. art@ ok

$OpenBSD$

Fix the NetBSD id strings.

branches: 1.3.4;
sync with NetBSD from 1999.05.24 (there is a reason for this date)
Mostly cleanups, but also a few improvements to pagedaemon for better
handling of low memory and/or low swap conditions.

add OpenBSD tags

Import of uvm from NetBSD. Some local changes, some code disabled

Simplify the aiodone daemon which is only used for async writes.

- Remove unused support for asynchronous read, including error conditions

- Grab the proper lock for each page that has been written to swap. This
allows to enable an assertion in uvm_page_unbusy().

- Move the uvm_anon_release() call outside of uvm_page_unbusy() and
assert for the different anon cases.

ok beck@, kettenis@

Constify and use C99 initializer for "struct uvm_pagerops".

While here put some KERNEL_ASSERT_LOCKED() in the functions called from
the page fault handler. The removal of locking of `uobj' will need to be
revisited and these are good indicator that something is missing and that
many comments are lying.

ok kettenis

Chuck Cranor rescinded clauses in his license
on the 2nd of February 2011 in NetBSD.

http://marc.info/?l=netbsd-source-changes&m=129658899212732&w=2
http://marc.info/?l=netbsd-source-changes&m=129659095515558&w=2
http://marc.info/?l=netbsd-source-changes&m=129659157916514&w=2
http://marc.info/?l=netbsd-source-changes&m=129665962324372&w=2
http://marc.info/?l=netbsd-source-changes&m=129666033625342&w=2
http://marc.info/?l=netbsd-source-changes&m=129666052825545&w=2
http://marc.info/?l=netbsd-source-changes&m=129666922906480&w=2
http://marc.info/?l=netbsd-source-changes&m=129667725518082&w=2

forgot to say: aobj grow/shrink tweaks are mostly from Pedro Martelletto,
like the rest of tmpfs

allow aobj to shrink grow, for tmpfs support
A few tweaks asked by kettenis@
(code doesn't affect systems without mounted tmpfs at all)

okay beck@

Don't leak swapslots when doing a uvm_km_pgremove and a page is in swap only.

Before we were only calling uao_dropswap() if there was a page, maning
that if the buffer was swapped out then we would leak the slot.

Quite rare because only pipebuffers should swap from the kernel object,
but i've seen panics that implied this had happened (alpha.p for example).

ok thib@ after a lot of discussion and checking the semantics.

Put the PG_RELEASED changes diff back in.

This has has been tested very very thoroughly on all archs we have
excepting 88k and 68k. Please see cvs log for the individual commit
messages.

ok beck@, thib@

date based reversion of uvm to the 4th May.

We still have no idea why this stops the crashes. but it does.

a machine forced to 64mb of ram cycled 10GB through swap with this diff
and is still running as I type this. Other tests by ariane@ and thib@
also seem to show that it's alright.

ok deraadt@, thib@, ariane@

Backout all the PG_RELEASED changes.

This is for the same reason as the earlier backouts, to avoid the bug
either added or exposed sometime around c2k9. This *should* be the last
one.

prompted by deraadt@

ok ariane@

The first step in cleaning up the use of PG_RELEASED for uvm objects.

Now, the PG_ RELEASED flag currently has two (maybe three) uses. The
valid one is for use with async io where we want to free the page after
we've paged it out. The other ones are "oh i'd like to free this, but
someone else is playing with it". It's simpler to just sleep on the
damned page instead and stop the fiddling.

First step does uao's: in uao_detach, sleep on the object and free it
when we're clean, instead of setting a flag so it's freed after. In
uao_flush, do the same. Change the interation over the object in flush
so that we don't have to add marker pages or other such voodoo to the
list when we sleep (netbsd did that when they had a similar diff), just
use the hash always. We can now change uao_releasepg() to just free the
page, and not bother with the KILLME stuff. When the other objects are
fixed this hook will vanish.

Much discussion with art@ over the idea, and ariane@ over this specific
diff. As mentioned, this one is based loosely on a similar idea in
netbsd.

Been in my tree for a while, survived many make builds, etc, and forcing
paging using ariane's evil program.

ok ariane@, beck@.

First round of __P removal in sys

branches: 1.7.4;
Add support for disabling swap devices (swapctl -d).
Improve error handling on I/O errors to swap.
From NetBSD

Protect protypes, certain macros, and inlines from userland. Checked userland
with a 'make build'. From NetBSD. art@ ok

$OpenBSD$

Fix the NetBSD id strings.

branches: 1.3.4;
sync with NetBSD from 1999.05.24 (there is a reason for this date)
Mostly cleanups, but also a few improvements to pagedaemon for better
handling of low memory and/or low swap conditions.

add OpenBSD tags

Import of uvm from NetBSD. Some local changes, some code disabled

Constify and use C99 initializer for "struct uvm_pagerops".

While here put some KERNEL_ASSERT_LOCKED() in the functions called from
the page fault handler. The removal of locking of `uobj' will need to be
revisited and these are good indicator that something is missing and that
many comments are lying.

ok kettenis

Chuck Cranor rescinded clauses in his license
on the 2nd of February 2011 in NetBSD.

http://marc.info/?l=netbsd-source-changes&m=129658899212732&w=2
http://marc.info/?l=netbsd-source-changes&m=129659095515558&w=2
http://marc.info/?l=netbsd-source-changes&m=129659157916514&w=2
http://marc.info/?l=netbsd-source-changes&m=129665962324372&w=2
http://marc.info/?l=netbsd-source-changes&m=129666033625342&w=2
http://marc.info/?l=netbsd-source-changes&m=129666052825545&w=2
http://marc.info/?l=netbsd-source-changes&m=129666922906480&w=2
http://marc.info/?l=netbsd-source-changes&m=129667725518082&w=2

forgot to say: aobj grow/shrink tweaks are mostly from Pedro Martelletto,
like the rest of tmpfs

allow aobj to shrink grow, for tmpfs support
A few tweaks asked by kettenis@
(code doesn't affect systems without mounted tmpfs at all)

okay beck@

Don't leak swapslots when doing a uvm_km_pgremove and a page is in swap only.

Before we were only calling uao_dropswap() if there was a page, maning
that if the buffer was swapped out then we would leak the slot.

Quite rare because only pipebuffers should swap from the kernel object,
but i've seen panics that implied this had happened (alpha.p for example).

ok thib@ after a lot of discussion and checking the semantics.

Put the PG_RELEASED changes diff back in.

This has has been tested very very thoroughly on all archs we have
excepting 88k and 68k. Please see cvs log for the individual commit
messages.

ok beck@, thib@

date based reversion of uvm to the 4th May.

We still have no idea why this stops the crashes. but it does.

a machine forced to 64mb of ram cycled 10GB through swap with this diff
and is still running as I type this. Other tests by ariane@ and thib@
also seem to show that it's alright.

ok deraadt@, thib@, ariane@

Backout all the PG_RELEASED changes.

This is for the same reason as the earlier backouts, to avoid the bug
either added or exposed sometime around c2k9. This *should* be the last
one.

prompted by deraadt@

ok ariane@

The first step in cleaning up the use of PG_RELEASED for uvm objects.

Now, the PG_ RELEASED flag currently has two (maybe three) uses. The
valid one is for use with async io where we want to free the page after
we've paged it out. The other ones are "oh i'd like to free this, but
someone else is playing with it". It's simpler to just sleep on the
damned page instead and stop the fiddling.

First step does uao's: in uao_detach, sleep on the object and free it
when we're clean, instead of setting a flag so it's freed after. In
uao_flush, do the same. Change the interation over the object in flush
so that we don't have to add marker pages or other such voodoo to the
list when we sleep (netbsd did that when they had a similar diff), just
use the hash always. We can now change uao_releasepg() to just free the
page, and not bother with the KILLME stuff. When the other objects are
fixed this hook will vanish.

Much discussion with art@ over the idea, and ariane@ over this specific
diff. As mentioned, this one is based loosely on a similar idea in
netbsd.

Been in my tree for a while, survived many make builds, etc, and forcing
paging using ariane's evil program.

ok ariane@, beck@.

First round of __P removal in sys

branches: 1.7.4;
Add support for disabling swap devices (swapctl -d).
Improve error handling on I/O errors to swap.
From NetBSD

Protect protypes, certain macros, and inlines from userland. Checked userland
with a 'make build'. From NetBSD. art@ ok

$OpenBSD$

Fix the NetBSD id strings.

branches: 1.3.4;
sync with NetBSD from 1999.05.24 (there is a reason for this date)
Mostly cleanups, but also a few improvements to pagedaemon for better
handling of low memory and/or low swap conditions.

add OpenBSD tags

Import of uvm from NetBSD. Some local changes, some code disabled

Chuck Cranor rescinded clauses in his license
on the 2nd of February 2011 in NetBSD.

http://marc.info/?l=netbsd-source-changes&m=129658899212732&w=2
http://marc.info/?l=netbsd-source-changes&m=129659095515558&w=2
http://marc.info/?l=netbsd-source-changes&m=129659157916514&w=2
http://marc.info/?l=netbsd-source-changes&m=129665962324372&w=2
http://marc.info/?l=netbsd-source-changes&m=129666033625342&w=2
http://marc.info/?l=netbsd-source-changes&m=129666052825545&w=2
http://marc.info/?l=netbsd-source-changes&m=129666922906480&w=2
http://marc.info/?l=netbsd-source-changes&m=129667725518082&w=2

forgot to say: aobj grow/shrink tweaks are mostly from Pedro Martelletto,
like the rest of tmpfs

allow aobj to shrink grow, for tmpfs support
A few tweaks asked by kettenis@
(code doesn't affect systems without mounted tmpfs at all)

okay beck@

Don't leak swapslots when doing a uvm_km_pgremove and a page is in swap only.

Before we were only calling uao_dropswap() if there was a page, maning
that if the buffer was swapped out then we would leak the slot.

Quite rare because only pipebuffers should swap from the kernel object,
but i've seen panics that implied this had happened (alpha.p for example).

ok thib@ after a lot of discussion and checking the semantics.

Put the PG_RELEASED changes diff back in.

This has has been tested very very thoroughly on all archs we have
excepting 88k and 68k. Please see cvs log for the individual commit
messages.

ok beck@, thib@

date based reversion of uvm to the 4th May.

We still have no idea why this stops the crashes. but it does.

a machine forced to 64mb of ram cycled 10GB through swap with this diff
and is still running as I type this. Other tests by ariane@ and thib@
also seem to show that it's alright.

ok deraadt@, thib@, ariane@

Backout all the PG_RELEASED changes.

This is for the same reason as the earlier backouts, to avoid the bug
either added or exposed sometime around c2k9. This *should* be the last
one.

prompted by deraadt@

ok ariane@

The first step in cleaning up the use of PG_RELEASED for uvm objects.

Now, the PG_ RELEASED flag currently has two (maybe three) uses. The
valid one is for use with async io where we want to free the page after
we've paged it out. The other ones are "oh i'd like to free this, but
someone else is playing with it". It's simpler to just sleep on the
damned page instead and stop the fiddling.

First step does uao's: in uao_detach, sleep on the object and free it
when we're clean, instead of setting a flag so it's freed after. In
uao_flush, do the same. Change the interation over the object in flush
so that we don't have to add marker pages or other such voodoo to the
list when we sleep (netbsd did that when they had a similar diff), just
use the hash always. We can now change uao_releasepg() to just free the
page, and not bother with the KILLME stuff. When the other objects are
fixed this hook will vanish.

Much discussion with art@ over the idea, and ariane@ over this specific
diff. As mentioned, this one is based loosely on a similar idea in
netbsd.

Been in my tree for a while, survived many make builds, etc, and forcing
paging using ariane's evil program.

ok ariane@, beck@.

First round of __P removal in sys

branches: 1.7.4;
Add support for disabling swap devices (swapctl -d).
Improve error handling on I/O errors to swap.
From NetBSD

Protect protypes, certain macros, and inlines from userland. Checked userland
with a 'make build'. From NetBSD. art@ ok

$OpenBSD$

Fix the NetBSD id strings.

branches: 1.3.4;
sync with NetBSD from 1999.05.24 (there is a reason for this date)
Mostly cleanups, but also a few improvements to pagedaemon for better
handling of low memory and/or low swap conditions.

add OpenBSD tags

Import of uvm from NetBSD. Some local changes, some code disabled